sysctl: remove struct ctl_path

All usages of this struct have been removed from the kernel tree.

The struct is still referenced by scripts/check-sysctl-docs but that
script is broken anyways as it only supports the register_sysctl_paths()
API and not the currently used register_sysctl() one.

Fixes: 0199849acd07 ("sysctl: remove register_sysctl_paths()")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR

It seems it was never used.

Fixes: 2f2665c13af4 ("sysctl: replace child with an enumeration")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

proc: sysctl: prevent aliased sysctls from getting passed to init

The code that checks for unknown boot options is unaware of the sysctl
alias facility, which maps bootparams to sysctl values. If a user sets
an old value that has a valid alias, a message about an invalid
parameter will be printed during boot, and the parameter will get passed
to init. Fix by checking for the existence of aliased parameters in the
unknown boot parameter code. If an alias exists, don't return an error
or pass the value to init.

Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Cc: stable@vger.kernel.org
Fixes: 0a477e1ae21b ("kernel/sysctl: support handling command line aliases")
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: Add size arg to __register_sysctl_init

This commit adds table_size to __register_sysctl_init in preparation for
the removal of the sentinel elements in the ctl_table arrays (last empty
markers). And though we do *not* remove any sentinels in this commit, we
set things up by calculating the ctl_table array size with ARRAY_SIZE.

We add a table_size argument to __register_sysctl_init and modify the
register_sysctl_init macro to calculate the array size with ARRAY_SIZE.
The original callers do not need to be updated as they will go through
the new macro.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: Add size to register_sysctl

This commit adds table_size to register_sysctl in preparation for the
removal of the sentinel elements in the ctl_table arrays (last empty
markers). And though we do *not* remove any sentinels in this commit, we
set things up by either passing the table_size explicitly or using
ARRAY_SIZE on the ctl_table arrays.

We replace the register_syctl function with a macro that will add the
ARRAY_SIZE to the new register_sysctl_sz function. In this way the
callers that are already using an array of ctl_table structs do not
change. For the callers that pass a ctl_table array pointer, we pass the
table_size to register_sysctl_sz instead of the macro.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: Add a size arg to __register_sysctl_table

We make these changes in order to prepare __register_sysctl_table and
its callers for when we remove the sentinel element (empty element at
the end of ctl_table arrays). We don't actually remove any sentinels in
this commit, but we *do* make sure to use ARRAY_SIZE so the table_size
is available when the removal occurs.

We add a table_size argument to __register_sysctl_table and adjust
callers, all of which pass ctl_table pointers and need an explicit call
to ARRAY_SIZE. We implement a size calculation in register_net_sysctl in
order to forward the size of the array pointer received from the network
register calls.

The new table_size argument does not yet have any effect in the
init_header call which is still dependent on the sentinel's presence.
table_size *does* however drive the `kzalloc` allocation in
__register_sysctl_table with no adverse effects as the allocated memory
is either one element greater than the calculated ctl_table array (for
the calls in ipc_sysctl.c, mq_sysctl.c and ucount.c) or the exact size
of the calculated ctl_table array (for the call from sysctl_net.c and
register_sysctl). This approach will allows us to "just" remove the
sentinel without further changes to __register_sysctl_table as
table_size will represent the exact size for all the callers at that
point.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: Add ctl_table_size to ctl_table_header

The new ctl_table_size element will hold the size of the ctl_table
arrays contained in the ctl_table_header. This value should eventually
be passed by the callers to the sysctl register infrastructure. And
while this commit introduces the variable, it does not set nor use it
because that requires case by case considerations for each caller.

It provides two important things: (1) A place to put the
result of the ctl_table array calculation when it gets introduced for
each caller. And (2) the size that will be used as the additional
stopping criteria in the list_for_each_table_entry macro (to be added
when all the callers are migrated)

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: replace child with an enumeration

This is part of the effort to remove the empty element at the end of
ctl_table structs. "child" was a deprecated elem in this struct and was
being used to differentiate between two types of ctl_tables: "normal"
and "permanently emtpy".

What changed?:
* Replace "child" with an enumeration that will have two values: the
default (0) and the permanently empty (1). The latter is left at zero
so when struct ctl_table is created with kzalloc or in a local
context, it will have the zero value by default. We document the
new enum with kdoc.
* Remove the "empty child" check from sysctl_check_table
* Remove count_subheaders function as there is no longer a need to
calculate how many headers there are for every child
* Remove the recursive call to unregister_sysctl_table as there is no
need to traverse down the child tree any longer
* Add a new SYSCTL_PERM_EMPTY_DIR binary flag
* Remove the last remanence of child from partport/procfs.c

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: Refactor base paths registrations

This is part of the general push to deprecate register_sysctl_paths and
register_sysctl_table. The old way of doing this through
register_sysctl_base and DECLARE_SYSCTL_BASE macro is replaced with a
call to register_sysctl_init. The 5 base paths affected are: "kernel",
"vm", "debug", "dev" and "fs".

We remove the register_sysctl_base function and the DECLARE_SYSCTL_BASE
macro since they are no longer needed.

In order to quickly acertain that the paths did not actually change I
executed `find /proc/sys/ | sha1sum` and made sure that the sha was the
same before and after the commit.

We end up saving 563 bytes with this change:

./scripts/bloat-o-meter vmlinux.0.base vmlinux.1.refactor-base-paths
add/remove: 0/5 grow/shrink: 2/0 up/down: 77/-640 (-563)
Function old new delta
sysctl_init_bases 55 111 +56
init_fs_sysctls 12 33 +21
vm_base_table 128 - -128
kernel_base_table 128 - -128
fs_base_table 128 - -128
dev_base_table 128 - -128
debug_base_table 128 - -128
Total: Before=21258215, After=21257652, chg -0.00%

[mcgrof: modified to use register_sysctl_init() over register_sysctl()
and add bloat-o-meter stats]

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Christian Brauner <brauner@kernel.org>

sysctl: stop exporting register_sysctl_table

We make register_sysctl_table static because the only function calling
it is in fs/proc/proc_sysctl.c (__register_sysctl_base). We remove it
from the sysctl.h header and modify the documentation in both the header
and proc_sysctl.c files to mention "register_sysctl" instead of
"register_sysctl_table".

This plus the commits that remove register_sysctl_table from parport
save 217 bytes:

./scripts/bloat-o-meter .bsysctl/vmlinux.old .bsysctl/vmlinux.new
add/remove: 0/1 grow/shrink: 5/1 up/down: 458/-675 (-217)
Function old new delta
__register_sysctl_base 8 286 +278
parport_proc_register 268 379 +111
parport_device_proc_register 195 247 +52
kzalloc.constprop 598 608 +10
parport_default_proc_register 62 69 +7
register_sysctl_table 291 - -291
parport_sysctl_template 1288 904 -384
Total: Before=8603076, After=8602859, chg -0.00%

Signed-off-by: Joel Granados <j.granados@samsung.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

sysctl: remove register_sysctl_paths()

The deprecation for register_sysctl_paths() is over. We can rejoice as
we nuke register_sysctl_paths(). The routine register_sysctl_table()
was the only user left of register_sysctl_paths(), so we can now just
open code and move the implementation over to what used to be
to __register_sysctl_paths().

The old dynamic struct ctl_table_set *set is now the point to
sysctl_table_root.default_set.

The old dynamic const struct ctl_path *path was being used in the
routine register_sysctl_paths() with a static:

static const struct ctl_path null_path[] = { {} };

Since this is a null path we can now just simplfy the old routine
and remove its use as its always empty.

This saves us a total of 230 bytes.

$ ./scripts/bloat-o-meter vmlinux.old vmlinux
add/remove: 2/7 grow/shrink: 1/1 up/down: 1015/-1245 (-230)
Function old new delta
register_leaf_sysctl_tables.constprop - 524 +524
register_sysctl_table 22 497 +475
__pfx_register_leaf_sysctl_tables.constprop - 16 +16
null_path 8 - -8
__pfx_register_sysctl_paths 16 - -16
__pfx_register_leaf_sysctl_tables 16 - -16
__pfx___register_sysctl_paths 16 - -16
__register_sysctl_base 29 12 -17
register_sysctl_paths 18 - -18
register_leaf_sysctl_tables 534 - -534
__register_sysctl_paths 620 - -620
Total: Before=21259666, After=21259436, chg -0.00%

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

mm: hugetlb_vmemmap: improve hugetlb_vmemmap code readability

There is a discussion about the name of hugetlb_vmemmap_alloc/free in
thread [1]. The suggestion suggested by David is rename "alloc/free" to
"optimize/restore" to make functionalities clearer to users, "optimize"
means the function will optimize vmemmap pages, while "restore" means
restoring its vmemmap pages discared before. This commit does this.

Another discussion is the confusion RESERVE_VMEMMAP_NR isn't used
explicitly for vmemmap_addr but implicitly for vmemmap_end in
hugetlb_vmemmap_alloc/free. David suggested we can compute what
hugetlb_vmemmap_init() does now at runtime. We do not need to worry for
the overhead of computing at runtime since the calculation is simple
enough and those functions are not in a hot path. This commit has the
following improvements:

1) The function suffixed name ("optimize/restore") is more expressive.
2) The logic becomes less weird in hugetlb_vmemmap_optimize/restore().
3) The hugetlb_vmemmap_init() does not need to be exported anymore.
4) A ->optimize_vmemmap_pages field in struct hstate is killed.
5) There is only one place where checks is_power_of_2(sizeof(struct
page)) instead of two places.
6) Add more comments for hugetlb_vmemmap_optimize/restore().
7) For external users, hugetlb_optimize_vmemmap_pages() is used for
detecting if the HugeTLB's vmemmap pages is optimizable originally.
In this commit, it is killed and we introduce a new helper
hugetlb_vmemmap_optimizable() to replace it. The name is more
expressive.

Link: https://lore.kernel.org/all/20220404074652.68024-2-songmuchun@bytedance.com/ [1]
Link: https://lkml.kernel.org/r/20220628092235.91270-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Will Deacon <will@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

sysctl: add proc_dointvec_ms_jiffies_minmax

add proc_dointvec_ms_jiffies_minmax to fit read msecs value to jiffies
with a limited range of values

Signed-off-by: Yuwei Wang <wangyuweihx@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: sysctl: introduce sysctl SYSCTL_THREE

This patch introdues the SYSCTL_THREE.

KUnit:
[00:10:14] ================ sysctl_test (10 subtests) =================
[00:10:14] [PASSED] sysctl_test_api_dointvec_null_tbl_data
[00:10:14] [PASSED] sysctl_test_api_dointvec_table_maxlen_unset
[00:10:14] [PASSED] sysctl_test_api_dointvec_table_len_is_zero
[00:10:14] [PASSED] sysctl_test_api_dointvec_table_read_but_position_set
[00:10:14] [PASSED] sysctl_test_dointvec_read_happy_single_positive
[00:10:14] [PASSED] sysctl_test_dointvec_read_happy_single_negative
[00:10:14] [PASSED] sysctl_test_dointvec_write_happy_single_positive
[00:10:14] [PASSED] sysctl_test_dointvec_write_happy_single_negative
[00:10:14] [PASSED] sysctl_test_api_dointvec_write_single_less_int_min
[00:10:14] [PASSED] sysctl_test_api_dointvec_write_single_greater_int_max
[00:10:14] =================== [PASSED] sysctl_test ===================

./run_kselftest.sh -c sysctl
...
ok 1 selftests: sysctl: sysctl.sh

Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Simon Horman <horms@verge.net.au>
Cc: Julian Anastasov <ja@ssi.bg>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Cc: Akhmat Karakotov <hmukos@yandex-team.ru>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/linux/sysctl.h: fix register_sysctl_mount_point() return type

The CONFIG_SYSCTL=n stub returns the wrong type.

Fixes: ee9efac48a082 ("sysctl: add helper to register a sysctl mount point")
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Tong Zhang <ztong0001@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/sysctl.c: rename sysctl_init() to sysctl_init_bases()

Rename sysctl_init() to sysctl_init_bases() so to reflect exactly what
this is doing.

Link: https://lkml.kernel.org/r/20211129211943.640266-4-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: add and use base directory declarer and registration helper

Patch series "sysctl: add and use base directory declarer and
registration helper".

In this patch series we start addressing base directories, and so we
start with the "fs" sysctls. The end goal is we end up completely
moving all "fs" sysctl knobs out from kernel/sysctl.

This patch (of 6):

Add a set of helpers which can be used to declare and register base
directory sysctls on their own. We do this so we can later move each of
the base sysctl directories like "fs", "kernel", etc, to their own
respective files instead of shoving the declarations and registrations
all on kernel/sysctl.c. The lazy approach has caught up and with this,
we just end up extending the list of base directories / sysctls on one
file and this makes maintenance difficult due to merge conflicts from
many developers.

The declarations are used first by kernel/sysctl.c for registration its
own base which over time we'll try to clean up. It will be used in the
next patch to demonstrate how to cleanly deal with base sysctl
directories.

[mcgrof@kernel.org: null-terminate the ctl_table arrays]
Link: https://lkml.kernel.org/r/YafJY3rXDYnjK/gs@bombadil.infradead.org

Link: https://lkml.kernel.org/r/20211129211943.640266-1-mcgrof@kernel.org
Link: https://lkml.kernel.org/r/20211129211943.640266-2-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs: move pipe sysctls to is own file

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong. The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move the pipe sysctls to its own file.

Link: https://lkml.kernel.org/r/20211129205548.605569-10-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: move maxolduid as a sysctl specific const

The maxolduid value is only shared for sysctl purposes for use on a max
range. Just stuff this into our shared const array.

[akpm@linux-foundation.org: fix sysctl_vals[], per Mickaël]

Link: https://lkml.kernel.org/r/20211129205548.605569-5-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: share unsigned long const values

Provide a way to share unsigned long values. This will allow others to
not have to re-invent these values.

Link: https://lkml.kernel.org/r/20211124231435.1445213-9-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Qing Wang <wangqing@vivo.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: add helper to register a sysctl mount point

The way to create a subdirectory on top of sysctl_mount_point is a bit
obscure, and *why* we do that even so more. Provide a helper which
makes it clear why we do this.

[akpm@linux-foundation.org: export register_sysctl_mount_point() to
modules]

Link: https://lkml.kernel.org/r/20211124231435.1445213-4-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Qing Wang <wangqing@vivo.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

random: move the random sysctl declarations to its own file

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong. The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move the random sysctls to their own file and use
register_sysctl_init().

[mcgrof@kernel.org: commit log update to justify the move]

Link: https://lkml.kernel.org/r/20211124231435.1445213-3-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Qing Wang <wangqing@vivo.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

firmware_loader: move firmware sysctl to its own files

Patch series "sysctl: 3rd set of kernel/sysctl cleanups", v2.

This is the third set of patches to help address cleaning the kitchen
seink in kernel/sysctl.c and to move sysctls away to where they are
actually implemented / used.

This patch (of 8):

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong. The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move the firmware configuration sysctl table to the only place where
it is used, and make it clear that if sysctls are disabled this is not
used.

[akpm@linux-foundation.org: export register_firmware_config_sysctl and unregister_firmware_config_sysctl to modules]
[akpm@linux-foundation.org: use EXPORT_SYMBOL_NS_GPL instead]
[sfr@canb.auug.org.au: fix that so it compiles]
Link: https://lkml.kernel.org/r/20211201160626.401d828d@canb.auug.org.au
[mcgrof@kernel.org: major commit log update to justify the move]

Link: https://lkml.kernel.org/r/20211124231435.1445213-1-mcgrof@kernel.org
Link: https://lkml.kernel.org/r/20211124231435.1445213-2-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Qing Wang <wangqing@vivo.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

eventpoll: simplify sysctl declaration with register_sysctl()

The kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong. The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move the epoll_table sysctl to fs/eventpoll.c and use
register_sysctl().

Link: https://lkml.kernel.org/r/20211123202422.819032-9-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Qing Wang <wangqing@vivo.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: move some boundary constants from sysctl.c to sysctl_vals

sysctl has helpers which let us specify boundary values for a min or max
int value. Since these are used for a boundary check only they don't
change, so move these variables to sysctl_vals to avoid adding duplicate
variables. This will help with our cleanup of kernel/sysctl.c.

[akpm@linux-foundation.org: update it for "mm/pagealloc: sysctl: change watermark_scale_factor max limit to 30%"]
[mcgrof@kernel.org: major rebase]

Link: https://lkml.kernel.org/r/20211123202347.818157-3-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qing Wang <wangqing@vivo.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: add a new register_sysctl_init() interface

Patch series "sysctl: first set of kernel/sysctl cleanups", v2.

Finally had time to respin the series of the work we had started last
year on cleaning up the kernel/sysct.c kitchen sink. People keeps
stuffing their sysctls in that file and this creates a maintenance
burden. So this effort is aimed at placing sysctls where they actually
belong.

I'm going to split patches up into series as there is quite a bit of
work.

This first set adds register_sysctl_init() for uses of registerting a
sysctl on the init path, adds const where missing to a few places,
generalizes common values so to be more easy to share, and starts the
move of a few kernel/sysctl.c out where they belong.

The majority of rework on v2 in this first patch set is 0-day fixes.
Eric Biederman's feedback is later addressed in subsequent patch sets.

I'll only post the first two patch sets for now. We can address the
rest once the first two patch sets get completely reviewed / Acked.

This patch (of 9):

The kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong. The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

Today though folks heavily rely on tables on kernel/sysctl.c so they can
easily just extend this table with their needed sysctls. In order to
help users move their sysctls out we need to provide a helper which can
be used during code initialization.

We special-case the initialization use of register_sysctl() since it
*is* safe to fail, given all that sysctls do is provide a dynamic
interface to query or modify at runtime an existing variable. So the
use case of register_sysctl() on init should *not* stop if the sysctls
don't end up getting registered. It would be counter productive to stop
boot if a simple sysctl registration failed.

Provide a helper for init then, and document the recommended init levels
to use for callers of this routine. We will later use this in
subsequent patches to start slimming down kernel/sysctl.c tables and
moving sysctl registration to the code which actually needs these
sysctls.

[mcgrof@kernel.org: major commit log and documentation rephrasing also moved to fs/proc/proc_sysctl.c ]

Link: https://lkml.kernel.org/r/20211123202347.818157-1-mcgrof@kernel.org
Link: https://lkml.kernel.org/r/20211123202347.818157-2-mcgrof@kernel.org
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Qing Wang <wangqing@vivo.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <jejb@linux.ibm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: introduce new proc handler proc_dobool

This is to let bool variable could be correctly displayed in
big/little endian sysctl procfs. sizeof(bool) is arch dependent,
proc_dobool should work in all arches.

Suggested-by: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Signed-off-by: Jia He <hejianet@gmail.com>
[thuth: rebased the patch to the current kernel version]
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

sysctl: add proc_dou8vec_minmax()

Networking has many sysctls that could fit in one u8.

This patch adds proc_dou8vec_minmax() for this purpose.

Note that the .extra1 and .extra2 fields are pointing
to integers, because it makes conversions easier.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

all arch: remove system call sys_sysctl

Since commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
sys_sysctl is actually unavailable: any input can only return an error.

We have been warning about people using the sysctl system call for years
and believe there are no more users. Even if there are users of this
interface if they have not complained or fixed their code by now they
probably are not going to, so there is no point in warning them any
longer.

So completely remove sys_sysctl on all architectures.

[nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu]
Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org> [arm/arm64]
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bin Meng <bin.meng@windriver.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: chenzefeng <chenzefeng2@huawei.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Diego Elio Pettenò <flameeyes@flameeyes.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kars de Jong <jongk@linux-m68k.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Paul Burton <paulburton@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Sven Schnelle <svens@stackframe.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zhou Yanjie <zhouyanjie@wanyeetech.com>
Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/sysctl: support setting sysctl parameters from kernel command line

Patch series "support setting sysctl parameters from kernel command line", v3.

This series adds support for something that seems like many people
always wanted but nobody added it yet, so here's the ability to set
sysctl parameters via kernel command line options in the form of
sysctl.vm.something=1

The important part is Patch 1. The second, not so important part is an
attempt to clean up legacy one-off parameters that do the same thing as
a sysctl. I don't want to remove them completely for compatibility
reasons, but with generic sysctl support the idea is to remove the
one-off param handlers and treat the parameters as aliases for the
sysctl variants.

I have identified several parameters that mention sysctl counterparts in
Documentation/admin-guide/kernel-parameters.txt but there might be more.
The conversion also has varying level of success:

- numa_zonelist_order is converted in Patch 2 together with adding the
necessary infrastructure. It's easy as it doesn't really do anything
but warn on deprecated value these days.

- hung_task_panic is converted in Patch 3, but there's a downside that
now it only accepts 0 and 1, while previously it was any integer
value

- nmi_watchdog maps to two sysctls nmi_watchdog and hardlockup_panic,
so there's no straighforward conversion possible

- traceoff_on_warning is a flag without value and it would be required
to handle that somehow in the conversion infractructure, which seems
pointless for a single flag

This patch (of 5):

A recently proposed patch to add vm_swappiness command line parameter in
addition to existing sysctl [1] made me wonder why we don't have a
general support for passing sysctl parameters via command line.

Googling found only somebody else wondering the same [2], but I haven't
found any prior discussion with reasons why not to do this.

Settings the vm_swappiness issue aside (the underlying issue might be
solved in a different way), quick search of kernel-parameters.txt shows
there are already some that exist as both sysctl and kernel parameter -
hung_task_panic, nmi_watchdog, numa_zonelist_order, traceoff_on_warning.

A general mechanism would remove the need to add more of those one-offs
and might be handy in situations where configuration by e.g.
/etc/sysctl.d/ is impractical.

Hence, this patch adds a new parse_args() pass that looks for parameters
prefixed by 'sysctl.' and tries to interpret them as writes to the
corresponding sys/ files using an temporary in-kernel procfs mount.
This mechanism was suggested by Eric W. Biederman [3], as it handles
all dynamically registered sysctl tables, even though we don't handle
modular sysctls. Errors due to e.g. invalid parameter name or value
are reported in the kernel log.

The processing is hooked right before the init process is loaded, as
some handlers might be more complicated than simple setters and might
need some subsystems to be initialized. At the moment the init process
can be started and eventually execute a process writing to /proc/sys/
then it should be also fine to do that from the kernel.

Sysctls registered later on module load time are not set by this
mechanism - it's expected that in such scenarios, setting sysctl values
from userspace is practical enough.

[1] https://lore.kernel.org/r/BL0PR02MB560167492CA4094C91589930E9FC0@BL0PR02MB5601.namprd02.prod.outlook.com/
[2] https://unix.stackexchange.com/questions/558802/how-to-set-sysctl-using-kernel-command-line-parameter
[3] https://lore.kernel.org/r/87bloj2skm.fsf@x220.int.ebiederm.org/

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: "Guilherme G . Piccoli" <gpiccoli@canonical.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Link: http://lkml.kernel.org/r/20200427180433.7029-1-vbabka@suse.cz
Link: http://lkml.kernel.org/r/20200427180433.7029-2-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: pass kernel pointers to ->proc_handler

Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sysctl: remove all extern declaration from sysctl.c

Extern declarations in .c files are a bad style and can lead to
mismatches. Use existing definitions in headers where they exist,
and otherwise move the external declarations to suitable header
files.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/sysctl.h: inline braces for ctl_table and ctl_table_header

Fix coding style of "struct ctl_table" and "struct ctl_table_header" to
have inline braces.

Besides the wide use of this proposed cose style, this change helps to
find at a glance the struct definition when navigating the code.

Link: http://lkml.kernel.org/r/20190903154906.188651-1-balsini@android.com
Signed-off-by: Alessio Balsini <balsini@android.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/sysctl: add shared variables for range check

In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range. This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

$ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

# scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
Data old new delta
sysctl_vals - 12 +12
__kstrtab_sysctl_vals - 12 +12
max 14 10 -4
int_max 16 - -16
one 68 - -68
zero 128 28 -100
Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: define proc_do_static_key()

Convert proc_dointvec_minmax_bpf_stats() into a more generic
helper, since we are going to use jump labels more often.

Note that sysctl_bpf_stats_enabled is removed, since
it is no longer needed/used.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

pipe, sysctl: remove pipe_proc_fn()

pipe_proc_fn() is no longer needed, as it only calls through to
proc_dopipe_max_size(). Just put proc_dopipe_max_size() in the ctl_table
entry directly, and remove the unneeded EXPORT_SYMBOL() and the ENOSYS
stub for it.

(The reason the ENOSYS stub isn't needed is that the pipe-max-size
ctl_table entry is located directly in 'kern_table' rather than being
registered separately. Therefore, the entry is already only defined when
the kernel is built with sysctl support.)

Link: http://lkml.kernel.org/r/20180111052902.14409-3-ebiggers3@gmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

pipe: add proc_dopipe_max_size() to safely assign pipe_max_size

pipe_max_size is assigned directly via procfs sysctl:

static struct ctl_table fs_table[] = {
...
{
.procname = "pipe-max-size",
.data = &pipe_max_size,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &pipe_proc_fn,
.extra1 = &pipe_min_size,
},
...

int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
size_t *lenp, loff_t *ppos)
{
...
ret = proc_dointvec_minmax(table, write, buf, lenp, ppos)
...

and then later rounded in-place a few statements later:

...
pipe_max_size = round_pipe_size(pipe_max_size);
...

This leaves a window of time between initial assignment and rounding
that may be visible to other threads. (For example, one thread sets a
non-rounded value to pipe_max_size while another reads its value.)

Similar reads of pipe_max_size are potentially racy:

pipe.c :: alloc_pipe_info()
pipe.c :: pipe_set_size()

Add a new proc_dopipe_max_size() that consolidates reading the new value
from the user buffer, verifying bounds, and calling round_pipe_size()
with a single assignment to pipe_max_size.

Link: http://lkml.kernel.org/r/1507658689-11669-4-git-send-email-joe.lawrence@redhat.com
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: add register_sysctl() dummy helper

register_sysctl() has been around for five years with commit
fea478d4101a ("sysctl: Add register_sysctl for normal sysctl users") but
now that arm64 started using it, I ran into a compile error:

arch/arm64/kernel/armv8_deprecated.c: In function 'register_insn_emulation_sysctl':
arch/arm64/kernel/armv8_deprecated.c:257:2: error: implicit declaration of function 'register_sysctl'

This adds a inline function like we already have for
register_sysctl_paths() and register_sysctl_table().

Link: http://lkml.kernel.org/r/20171106133700.558647-1-arnd@arndb.de
Fixes: 38b9aeb32fa7 ("arm64: Port deprecated instruction emulation to new sysctl interface")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Alex Benne <alex.bennee@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sysctl: add unsigned int range support

To keep parity with regular int interfaces provide the an unsigned int
proc_douintvec_minmax() which allows you to specify a range of allowed
valid numbers.

Adding proc_douintvec_minmax_sysadmin() is easy but we can wait for an
actual user for that.

Link: http://lkml.kernel.org/r/20170519033554.18592-6-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: Fix proc_sys_prune_dcache to hold a sb reference

Andrei Vagin writes:
FYI: This bug has been reproduced on 4.11.7
> BUG: Dentry ffff895a3dd01240{i=4e7c09a,n=lo} still in use (1) [unmount of proc proc]
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 13588 at fs/dcache.c:1445 umount_check+0x6e/0x80
> CPU: 1 PID: 13588 Comm: kworker/1:1 Not tainted 4.11.7-200.fc25.x86_64 #1
> Hardware name: CompuLab sbc-flt1/fitlet, BIOS SBCFLT_0.08.04 06/27/2015
> Workqueue: events proc_cleanup_work
> Call Trace:
> dump_stack+0x63/0x86
> __warn+0xcb/0xf0
> warn_slowpath_null+0x1d/0x20
> umount_check+0x6e/0x80
> d_walk+0xc6/0x270
> ? dentry_free+0x80/0x80
> do_one_tree+0x26/0x40
> shrink_dcache_for_umount+0x2d/0x90
> generic_shutdown_super+0x1f/0xf0
> kill_anon_super+0x12/0x20
> proc_kill_sb+0x40/0x50
> deactivate_locked_super+0x43/0x70
> deactivate_super+0x5a/0x60
> cleanup_mnt+0x3f/0x90
> mntput_no_expire+0x13b/0x190
> kern_unmount+0x3e/0x50
> pid_ns_release_proc+0x15/0x20
> proc_cleanup_work+0x15/0x20
> process_one_work+0x197/0x450
> worker_thread+0x4e/0x4a0
> kthread+0x109/0x140
> ? process_one_work+0x450/0x450
> ? kthread_park+0x90/0x90
> ret_from_fork+0x2c/0x40
> ---[ end trace e1c109611e5d0b41 ]---
> VFS: Busy inodes after unmount of proc. Self-destruct in 5 seconds. Have a nice day...
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: _raw_spin_lock+0xc/0x30
> PGD 0

Fix this by taking a reference to the super block in proc_sys_prune_dcache.

The superblock reference is the core of the fix however the sysctl_inodes
list is converted to a hlist so that hlist_del_init_rcu may be used. This
allows proc_sys_prune_dache to remove inodes the sysctl_inodes list, while
not causing problems for proc_sys_evict_inode when if it later choses to
remove the inode from the sysctl_inodes list. Removing inodes from the
sysctl_inodes list allows proc_sys_prune_dcache to have a progress
guarantee, while still being able to drop all locks. The fact that
head->unregistering is set in start_unregistering ensures that no more
inodes will be added to the the sysctl_inodes list.

Previously the code did a dance where it delayed calling iput until the
next entry in the list was being considered to ensure the inode remained on
the sysctl_inodes list until the next entry was walked to. The structure
of the loop in this patch does not need that so is much easier to
understand and maintain.

Cc: stable@vger.kernel.org
Reported-by: Andrei Vagin <avagin@gmail.com>
Tested-by: Andrei Vagin <avagin@openvz.org>
Fixes: ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.")
Fixes: d6cffbbe9a7e ("proc/sysctl: prune stale dentries during unregistering")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

randstruct: Mark various structs for randomization

This marks many critical kernel structures for randomization. These are
structures that have been targeted in the past in security exploits, or
contain functions pointers, pointers to function pointer tables, lists,
workqueues, ref-counters, credentials, permissions, or are otherwise
sensitive. This initial list was extracted from Brad Spengler/PaX Team's
code in the last public patch of grsecurity/PaX based on my understanding
of the code. Changes or omissions from the original code are mine and
don't reflect the original grsecurity/PaX code.

Left out of this list is task_struct, which requires special handling
and will be covered in a subsequent patch.

Signed-off-by: Kees Cook <keescook@chromium.org>

sysctl: Remove dead register_sysctl_root

The function no longer does anything. The is only a single caller of
register_sysctl_root when semantically there should be two. Remove
this function so that if someone decides this functionality is needed
again it will be obvious all of the callers of setup_sysctl_set need
to be audited and modified appropriately.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

proc/sysctl: prune stale dentries during unregistering

Currently unregistering sysctl table does not prune its dentries.
Stale dentries could slowdown sysctl operations significantly.

For example, command:

# for i in {1..100000} ; do unshare -n -- sysctl -a &> /dev/null ; done
creates a millions of stale denties around sysctls of loopback interface:

# sysctl fs.dentry-state
fs.dentry-state = 25812579 24724135 45 0 0 0

All of them have matching names thus lookup have to scan though whole
hash chain and call d_compare (proc_sys_compare) which checks them
under system-wide spinlock (sysctl_lock).

# time sysctl -a > /dev/null
real 1m12.806s
user 0m0.016s
sys 1m12.400s

Currently only memory reclaimer could remove this garbage.
But without significant memory pressure this never happens.

This patch collects sysctl inodes into list on sysctl table header and
prunes all their dentries once that table unregisters.

Konstantin Khlebnikov <khlebnikov@yandex-team.ru> writes:
> On 10.02.2017 10:47, Al Viro wrote:
>> how about >> the matching stats *after* that patch?
>
> dcache size doesn't grow endlessly, so stats are fine
>
> # sysctl fs.dentry-state
> fs.dentry-state = 92712 58376 45 0 0 0
>
> # time sysctl -a &>/dev/null
>
> real 0m0.013s
> user 0m0.004s
> sys 0m0.008s

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: handle error writing UINT_MAX to u32 fields

We have scripts which write to certain fields on 3.18 kernels but this
seems to be failing on 4.4 kernels. An entry which we write to here is
xfrm_aevent_rseqth which is u32.

echo 4294967295 > /proc/sys/net/core/xfrm_aevent_rseqth

Commit 230633d109e3 ("kernel/sysctl.c: detect overflows when converting
to int") prevented writing to sysctl entries when integer overflow
occurs. However, this does not apply to unsigned integers.

Heinrich suggested that we introduce a new option to handle 64 bit
limits and set min as 0 and max as UINT_MAX. This might not work as it
leads to issues similar to __do_proc_doulongvec_minmax. Alternatively,
we would need to change the datatype of the entry to 64 bit.

static int __do_proc_doulongvec_minmax(void *data, struct ctl_table
{
i = (unsigned long *) data; //This cast is causing to read beyond the size of data (u32)
vleft = table->maxlen / sizeof(unsigned long); //vleft is 0 because maxlen is sizeof(u32) which is lesser than sizeof(unsigned long) on x86_64.

Introduce a new proc handler proc_douintvec. Individual proc entries
will need to be updated to use the new handler.

[akpm@linux-foundation.org: coding-style fixes]
Fixes: 230633d109e3 ("kernel/sysctl.c:detect overflows when converting to int")
Link: http://lkml.kernel.org/r/1471479806-5252-1-git-send-email-subashab@codeaurora.org
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net: make net namespace sysctls belong to container's owner

If net namespace is attached to a user namespace let's make container's
root owner of sysctls affecting said network namespace instead of global
root.

This also allows us to clean up net_ctl_permissions() because we do not
need to fudge permissions anymore for the container's owner since it now
owns the objects in question.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: Stop implicitly passing current into sysctl_table_root.lookup

Passing nsproxy into sysctl_table_root.lookup was a premature
optimization in attempt to avoid depending on current. The
directory /proc/self/sys has not appeared and if and when
it does this code will need to be reviewed closely and reworked
anyway. So remove the premature optimization.

Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

uapi: move forward declarations of internal structures

Don't user forward declarations of internal kernel structures in headers
exported to userspace.

Move "struct completion;".
Move "struct task_struct;".

Link: http://lkml.kernel.org/r/20160713215808.GA22486@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: Allow creating permanently empty directories that serve as mountpoints.

Add a magic sysctl table sysctl_mount_point that when used to
create a directory forces that directory to be permanently empty.

Update the code to use make_empty_dir_inode when accessing permanently
empty directories.

Update the code to not allow adding to permanently empty directories.

Update /proc/sys/fs/binfmt_misc to be a permanently empty directory.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

kernel/sysctl.c: threads-max observe limits

Users can change the maximum number of threads by writing to
/proc/sys/kernel/threads-max.

With the patch the value entered is checked against the same limits that
apply when fork_init is called.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: remove typedef ctl_table

Remove the final user, and the typedef itself.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: Pass useful parameters to sysctl permissions

- Current is implicitly avaiable so passing current->nsproxy isn't useful.
- The ctl_table_header is needed to find how the sysctl table is connected
to the rest of sysctl.
- ctl_table_root is avaiable in the ctl_table_header so no need to it.

With these changes it becomes possible to write a version of
net_sysctl_permission that takes into account the network namespace of
the sysctl table, an important feature in extending the user namespace.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>

ipv4: Don't add deprecated new binary sysctl value.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Add sysctl knob to control early socket demux

This change is meant to add a control for disabling early socket demux.
The main motivation behind this patch is to provide an option to disable
the feature as it adds an additional cost to routing that reduces overall
throughput by up to 5%. For example one of my systems went from 12.1Mpps
to 11.6 after the early socket demux was added. It looks like the reason
for the regression is that we are now having to perform two lookups, first
the one for an established socket, and then the one for the routing table.

By adding this patch and toggling the value for ip_early_demux to 0 I am
able to get back to the 12.1Mpps I was previously seeing.

[ Move local variables in ip_rcv_finish() down into the basic
block in which they are actually used. -DaveM ]

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: Add register_sysctl for normal sysctl users

The plan is to convert all callers of register_sysctl_table
and register_sysctl_paths to register_sysctl. The interface
to register_sysctl is enough nicer this should make the callers
a bit more readable. Additionally after the conversion the
230 lines of backwards compatibility can be removed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Index sysctl directories with rbtrees.

One of the most important jobs of sysctl is to export network stack
tunables. Several of those tunables are per network device. In
several instances people are running with 1000+ network devices in
there network stacks, which makes the simple per directory linked list
in sysctl a scaling bottleneck. Replace O(N^2) sysctl insertion and
lookup times with O(NlogN) by using an rbtree to index the sysctl
directories.

Benchmark before:
make-dummies 0 999 -> 0.32s
rmmod dummy -> 0.12s
make-dummies 0 9999 -> 1m17s
rmmod dummy -> 17s

Benchmark after:
make-dummies 0 999 -> 0.074s
rmmod dummy -> 0.070s
make-dummies 0 9999 -> 3.4s
rmmod dummy -> 0.44s

Benchmark after (without dev_snmp6):
make-dummies 0 9999 -> 0.75s
rmmod dummy -> 0.44s
make-dummies 0 99999 -> 11s
rmmod dummy -> 4.3s

At 10,000 dummy devices the bottleneck becomes the time to add and
remove the files under /proc/sys/net/dev_snmp6. I have commented
out the code that adds and removes files under /proc/sys/net/dev_snmp6
and taken measurments of creating and destroying 100,000 dummies to
verify the sysctl continues to scale.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Make the header lists per directory.

Slightly enhance efficiency and clarity of the code by making the
header list per directory instead of per set.

Benchmark before:
make-dummies 0 999 -> 0.63s
rmmod dummy -> 0.12s
make-dummies 0 9999 -> 2m35s
rmmod dummy -> 18s

Benchmark after:
make-dummies 0 999 -> 0.32s
rmmod dummy -> 0.12s
make-dummies 0 9999 -> 1m17s
rmmod dummy -> 17s

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy

An nsproxy argument here has always been awkard and now the nsproxy argument
is completely unnecessary so remove it, replacing it with the set we want
the registered tables to show up in.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Replace root_list with links between sysctl_table_sets.

Piecing together directories by looking first in one directory
tree, than in another directory tree and finally in a third
directory tree makes it hard to verify that some directory
entries are not multiply defined and makes it hard to create
efficient implementations the sysctl filesystem.

Replace the sysctl wide list of roots with autogenerated
links from the core sysctl directory tree to the other
sysctl directory trees.

This simplifies sysctl directory reading and lookups as now
only entries in a single sysctl directory tree need to be
considered.

Benchmark before:
make-dummies 0 999 -> 0.44s
rmmod dummy -> 0.065s
make-dummies 0 9999 -> 1m36s
rmmod dummy -> 0.4s

Benchmark after:
make-dummies 0 999 -> 0.63s
rmmod dummy -> 0.12s
make-dummies 0 9999 -> 2m35s
rmmod dummy -> 18s

The slowdown is caused by the lookups used in insert_headers
and put_links to see if we need to add links or remove links.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Stop requiring explicit management of sysctl directories

Simplify the code and the sysctl semantics by autogenerating
sysctl directories when a sysctl table is registered that needs
the directories and autodeleting the directories when there are
no more sysctl tables registered that need them.

Autogenerating directories keeps sysctl tables from depending
on each other, removing all of the arcane register/unregister
ordering constraints and makes it impossible to get the order
wrong when reigsering and unregistering sysctl tables.

Autogenerating directories yields one unique entity that dentries
can point to, retaining the current effective use of the dcache.

Add struct ctl_dir as the type of these new autogenerated
directories.

The attached_by and attached_to fields in ctl_table_header are
removed as they are no longer needed.

The child field in ctl_table is no longer needed by the core of
the sysctl code. ctl_table.child can be removed once all of the
existing users have been updated.

Benchmark before:
make-dummies 0 999 -> 0.7s
rmmod dummy -> 0.07s
make-dummies 0 9999 -> 1m10s
rmmod dummy -> 0.4s

Benchmark after:
make-dummies 0 999 -> 0.44s
rmmod dummy -> 0.065s
make-dummies 0 9999 -> 1m36s
rmmod dummy -> 0.4s

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Add a root pointer to ctl_table_set

Add a ctl_table_root pointer to ctl_table set so it is easy to
go from a ctl_table_set to a ctl_table_root.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Initial support for auto-unregistering sysctl tables.

Add nreg to ctl_table_header. When nreg drops to 0 the ctl_table_header
will be unregistered.

Factor out drop_sysctl_table from unregister_sysctl_table, and add
the logic for decrementing nreg.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Remove the now unused ctl_table parent field.

While useful at one time for selinux and the sysctl sanity
checks those users no longer use the parent field and we can
safely remove it.

Inspired-by: Lucian Adrian Grijincu <lucian.grijincu@gmil.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: register only tables of sysctl files

Split the registration of a complex ctl_table array which may have
arbitrary numbers of directories (->child != NULL) and tables of files
into a series of simpler registrations that only register tables of files.

Graphically:

register('dir', { + file-a
+ file-b
+ subdir1
+ file-c
+ subdir2
+ file-d
+ file-e })

is transformed into:
wrapper->subheaders[0] = register('dir', {file1-a, file1-b})
wrapper->subheaders[1] = register('dir/subdir1', {file-c})
wrapper->subheaders[2] = register('dir/subdir2', {file-d, file-e})
return wrapper

This guarantees that __register_sysctl_table will only see a simple
ctl_table array with all entries having (->child == NULL).

Care was taken to pass the original simple ctl_table arrays to
__register_sysctl_table whenever possible.

This change is derived from a similar patch written
by Lucrian Grijincu.

Inspired-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Add support for register sysctl tables with a normal cstring path.

Make __register_sysctl_table the core sysctl registration operation and
make it take a char * string as path.

Now that binary paths have been banished into the real of backwards
compatibility in kernel/binary_sysctl.c where they can be safely
ignored there is no longer a need to use struct ctl_path to represent
path names when registering ctl_tables.

Start the transition to using normal char * strings to represent
pathnames when registering sysctl tables. Normal strings are easier
to deal with both in the internal sysctl implementation and for
programmers registering sysctl tables.

__register_sysctl_paths is turned into a backwards compatibility wrapper
that converts a ctl_path array into a normal char * string.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Remove the unnecessary sysctl_set parent concept.

In sysctl_net register the two networking roots in the proper order.

In register_sysctl walk the sysctl sets in the reverse order of the
sysctl roots.

Remove parent from ctl_table_set and setup_sysctl_set as it is no
longer needed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Implement retire_sysctl_set

This adds a small helper retire_sysctl_set to remove the intimate knowledge about
the how a sysctl_set is implemented from net/sysct_net.c

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Move the implementation into fs/proc/proc_sysctl.c

Move the core sysctl code from kernel/sysctl.c and kernel/sysctl_check.c
into fs/proc/proc_sysctl.c.

Currently sysctl maintenance is hampered by the sysctl implementation
being split across 3 files with artificial layering between them.
Consolidate the entire sysctl implementation into 1 file so that
it is easier to see what is going on and hopefully allowing for
simpler maintenance.

For functions that are now only used in fs/proc/proc_sysctl.c remove
their declarations from sysctl.h and make them static in fs/proc/proc_sysctl.c

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Register the base sysctl table like any other sysctl table.

Simplify the code by treating the base sysctl table like any other
sysctl table and register it with register_sysctl_table.

To ensure this table is registered early enough to avoid problems
call sysctl_init from proc_sys_init.

Rename sysctl_net.c:sysctl_init() to net_sysctl_init() to avoid
name conflicts now that kernel/sysctl.c:sysctl_init() is no longer
static.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Consolidate !CONFIG_SYSCTL handling

- In sysctl.h move functions only available if CONFIG_SYSCL
is defined inside of #ifdef CONFIG_SYSCTL

- Move the stub function definitions for !CONFIG_SYSCTL
into sysctl.h and make them static inlines.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: use umode_t for table permissions

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sysctl: add support for poll()

Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries. This adds a infrastructure to
allow files in sysctl fs to be pollable and implements it for hostname and
domainname.

[akpm@linux-foundation.org: s/declare/define/ for definitions]
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Greg KH <gregkh@suse.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipv4: NET_IPV4_ROUTE_GC_INTERVAL removal

removing obsoleted sysctl,
ip_rt_gc_interval variable no longer used since 2.6.38

Signed-off-by: Vasily Averin <vvs@sw.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: the include of rcupdate.h is only needed in the kernel

Fixes this built error:

include/linux/sysctl.h:28: included file 'linux/rcupdate.h' is not exported

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sysctl: the include of rcupdate.h is only needed in the kernel

Fixes this build-check error:

include/linux/sysctl.h:28: included file 'linux/rcupdate.h' is not exported

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

unfuck proc_sysctl ->d_compare()

a) struct inode is not going to be freed under ->d_compare();
however, the thing PROC_I(inode)->sysctl points to just might.
Fortunately, it's enough to make freeing that sucker delayed,
provided that we don't step on its ->unregistering, clear
the pointer to it in PROC_I(inode) before dropping the reference
and check if it's NULL in ->d_compare().

b) I'm not sure that we *can* walk into NULL inode here (we recheck
dentry->seq between verifying that it's still hashed / fetching
dentry->d_inode and passing it to ->d_compare() and there's no
negative hashed dentries in /proc/sys/*), but if we can walk into
that, we really should not have ->d_compare() return 0 on it!
Said that, I really suspect that this check can be simply killed.
Nick?

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sysctl: add proc_do_large_bitmap

The new function can be used to read/write large bitmaps via /proc. A
comma separated range format is used for compact output and input
(e.g. 1,3-4,10-10).

Writing into the file will first reset the bitmap then update it
based on the given input.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net neigh: Decouple per interface neighbour table controls from binary sysctls

Stop computing the number of neighbour table settings we have by
counting the number of binary sysctls. This behaviour was silly
and meant that we could not add another neighbour table setting
without also adding another binary sysctl.

Don't pass the binary sysctl path for neighour table entries
into neigh_sysctl_register. These parameters are no longer
used and so are just dead code.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net ipv4: Decouple ipv4 interface parameters from binary sysctl numbers

Stop using the binary sysctl enumeartion in sysctl.h as an index into
a per interface array. This leads to unnecessary binary sysctl number
allocation, and a fragility in data structure and implementation
because of unnecessary coupling.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: RFC3069, private VLAN proxy arp support

This is to be used together with switch technologies, like RFC3069,
that where the individual ports are not allowed to communicate with
each other, but they are allowed to talk to the upstream router. As
described in RFC 3069, it is possible to allow these hosts to
communicate through the upstream router by proxy_arp'ing.

This patch basically allow proxy arp replies back to the same
interface (from which the ARP request/solicitation was received).

Tunable per device via proc "proxy_arp_pvlan":
/proc/sys/net/ipv4/conf/*/proxy_arp_pvlan

This switch technology is known by different vendor names:
- In RFC 3069 it is called VLAN Aggregation.
- Cisco and Allied Telesyn call it Private VLAN.
- Hewlett-Packard call it Source-Port filtering or port-isolation.
- Ericsson call it MAC-Forced Forwarding (RFC Draft).

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: restore ip source validation

when using policy routing and the skb mark:
there are cases where a back path validation requires us
to use a different routing table for src ip validation than
the one used for mapping ingress dst ip.
One such a case is transparent proxying where we pretend to be
the destination system and therefore the local table
is used for incoming packets but possibly a main table would
be used on outbound.
Make the default behavior to allow the above and if users
need to turn on the symmetry via sysctl src_valid_mark

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: add missing comments

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

ipv4 05/05: add sysctl to accept packets with local source addresses

commit 8ec1e0ebe26087bfc5c0394ada5feb5758014fc8
Author: Patrick McHardy <kaber@trash.net>
Date: Thu Dec 3 12:16:35 2009 +0100

ipv4: add sysctl to accept packets with local source addresses

Change fib_validate_source() to accept packets with a local source address when
the "accept_local" sysctl is set for the incoming inet device. Combined with the
previous patches, this allows to communicate between multiple local interfaces
over the wire.

Signed-off-by: Patrick McHardy <kaber@trash.net>

Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: Remove CTL_NONE and CTL_UNNUMBERED

Now that the sysctl structures no longer have a ctl_name field
there is no reason to retain the definitions for CTL_NONE and
CTL_UNNUMBERED, or to explain their historic usage.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: kill dead ctl_handler definitions.

When removing the sysctl strategy routines I overlooked their definitions
in sysctl.h. So remove those unnecessary definitions now.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Remove the last of the generic binary sysctl support

Now that all of the users stopped using ctl_name and strategy it
is safe to remove the fields from struct ctl_table, and it is safe
to remove the stub strategy routines as well.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Don't look at ctl_name and strategy in the generic code

The ctl_name and strategy fields are unused, now that sys_sysctl
is a compatibility wrapper around /proc/sys. No longer looking
at them in the generic code is effectively what we are doing
now and provides the guarantee that during further cleanups
we can just remove references to those fields and everything
will work ok.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: Make do_sysctl static

Now that all of the architectures use compat_sys_sysctl do_sysctl
can become static.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

sysctl: remove "struct file *" argument of ->proc_handler

It's unused.

It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.

It _was_ used in two places at arch/frv for some reason.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net: add ARP notify option for devices

This adds another inet device option to enable gratuitous ARP
when device is brought up or address change. This is handy for
clusters or virtualization.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: simplify ->strategy

name and nlen parameters passed to ->strategy hook are unused, remove
them. In general ->strategy hook should know what it's doing, and don't
do something tricky for which, say, pointer to original userspace array
may be needed (name).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net> [ networking bits ]
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sanitize proc_sysctl

* keep references to ctl_table_head and ctl_table in /proc/sys inodes
* grab the former during operations, use the latter for access to
entry if that succeeds
* have ->d_compare() check if table should be seen for one who does lookup;
that allows us to avoid flipping inodes - if we have the same name resolve
to different things, we'll just keep several dentries and ->d_compare()
will reject the wrong ones.
* have ->lookup() and ->readdir() scan the table of our inode first, then
walk all ctl_table_header and scan ->attached_by for those that are
attached to our directory.
* implement ->getattr().
* get rid of insane amounts of tree-walking
* get rid of the need to know dentry in ->permission() and of the contortions
induced by that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[PATCH] sysctl: keep track of tree relationships

In a sense, that's the heart of the series. It's based on the following
property of the trees we are actually asked to add: they can be split into
stem that is already covered by registered trees and crown that is entirely
new. IOW, if a/b and a/c/d are introduced by our tree, then a/c is also
introduced by it.

That allows to associate tree and table entry with each node in the union;
while directory nodes might be covered by many trees, only one will cover
the node by its crown. And that will allow much saner logics for /proc/sys
in the next patches. This patch introduces the data structures needed to
keep track of that.

When adding a sysctl table, we find a "parent" one. Which is to say,
find the deepest node on its stem that already is present in one of the
tables from our table set or its ancestor sets. That table will be our
parent and that node in it - attachment point. Add our table to list
anchored in parent, have it refer the parent and contents of attachment
point. Also remember where its crown lives.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[PATCH] allow delayed freeing of ctl_table_header

Refcount the sucker; instead of freeing it by the end of unregistration
just drop the refcount and free only when it hits zero. Make sure that
we _always_ make ->unregistering non-NULL in start_unregistering().

That allows anybody to get a reference to such puppy, preventing its
freeing and reuse. It does *not* block unregistration. Anybody who
holds such a reference can
* try to grab a "use" reference (ctl_head_grab()); that will
succeeds if and only if it hadn't entered unregistration yet. If it
succeeds, we can use it in all normal ways until we release the "use"
reference (with ctl_head_finish()). Note that this relies on having
->unregistering become non-NULL in all cases when one starts to unregister
the sucker.
* keep pointers to ctl_table entries; they *can* be freed if
the entire thing is unregistered. However, if ctl_head_grab() succeeds,
we know that unregistration had not happened (and will not happen until
ctl_head_finish()) and such pointers can be used safely.

IOW, now we can have inodes under /proc/sys keep references to ctl_table
entries, protecting them with references to ctl_table_header and
grabbing the latter for the duration of operations that require access
to ctl_table. That won't cause deadlocks, since unregistration will not
be stopped by mere keeping a reference to ctl_table_header.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[PATCH] beginning of sysctl cleanup - ctl_table_set

New object: set of sysctls [currently - root and per-net-ns].
Contains: pointer to parent set, list of tables and "should I see this set?"
method (->is_seen(set)).
Current lists of tables are subsumed by that; net-ns contains such a beast.
->lookup() for ctl_table_root returns pointer to ctl_table_set instead of
that to ->list of that ctl_table_set.

[folded compile fixes by rdd for configs without sysctl]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sysctl: add the ->permissions callback on the ctl_table_root

When reading from/writing to some table, a root, which this table came from,
may affect this table's permissions, depending on who is working with the
table.

The core hunk is at the bottom of this patch. All the rest is just pushing
the ctl_table_root argument up to the sysctl_perm() function.

This will be mostly (only?) used in the net sysctls.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Denis V. Lunev <den@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: clean from unneeded extern and forward declarations

The do_sysctl_strategy isn't used outside kernel/sysctl.c, so this can be
static and without a prototype in header.

Besides, move this one and parse_table() above their callers and drop the
forward declarations of the latter call.

One more "besides" - fix two checkpatch warnings: space before a ( and an
extra space at the end of a line.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Denis V. Lunev <den@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/sysctl.h: remove empty #else

Remove an empty #else.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

capabilities: introduce per-process capability bounding set

The capability bounding set is a set beyond which capabilities cannot grow.
Currently cap_bset is per-system. It can be manipulated through sysctl,
but only init can add capabilities. Root can remove capabilities. By
default it includes all caps except CAP_SETPCAP.

This patch makes the bounding set per-process when file capabilities are
enabled. It is inherited at fork from parent. Noone can add elements,
CAP_SETPCAP is required to remove them.

One example use of this is to start a safer container. For instance, until
device namespaces or per-container device whitelists are introduced, it is
best to take CAP_MKNOD away from a container.

The bounding set will not affect pP and pE immediately. It will only
affect pP' and pE' after subsequent exec()s. It also does not affect pI,
and exec() does not constrain pI'. So to really start a shell with no way
of regain CAP_MKNOD, you would do

prctl(PR_CAPBSET_DROP, CAP_MKNOD);
cap_t cap = cap_get_proc();
cap_value_t caparray[1];
caparray[0] = CAP_MKNOD;
cap_set_flag(cap, CAP_INHERITABLE, 1, caparray, CAP_DROP);
cap_set_proc(cap);
cap_free(cap);

The following test program will get and set the bounding
set (but not pI). For instance

./bset get
(lists capabilities in bset)
./bset drop cap_net_raw
(starts shell with new bset)
(use capset, setuid binary, or binary with
file capabilities to try to increase caps)

************************************************************
cap_bound.c
************************************************************
#include <sys/prctl.h>
#include <linux/capability.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifndef PR_CAPBSET_READ
#define PR_CAPBSET_READ 23
#endif

#ifndef PR_CAPBSET_DROP
#define PR_CAPBSET_DROP 24
#endif

int usage(char *me)
{
printf("Usage: %s get\n", me);
printf(" %s drop <capability>\n", me);
return 1;
}

#define numcaps 32
char *captable[numcaps] = {
"cap_chown",
"cap_dac_override",
"cap_dac_read_search",
"cap_fowner",
"cap_fsetid",
"cap_kill",
"cap_setgid",
"cap_setuid",
"cap_setpcap",
"cap_linux_immutable",
"cap_net_bind_service",
"cap_net_broadcast",
"cap_net_admin",
"cap_net_raw",
"cap_ipc_lock",
"cap_ipc_owner",
"cap_sys_module",
"cap_sys_rawio",
"cap_sys_chroot",
"cap_sys_ptrace",
"cap_sys_pacct",
"cap_sys_admin",
"cap_sys_boot",
"cap_sys_nice",
"cap_sys_resource",
"cap_sys_time",
"cap_sys_tty_config",
"cap_mknod",
"cap_lease",
"cap_audit_write",
"cap_audit_control",
"cap_setfcap"
};

int getbcap(void)
{
int comma=0;
unsigned long i;
int ret;

printf("i know of %d capabilities\n", numcaps);
printf("capability bounding set:");
for (i=0; i<numcaps; i++) {
ret = prctl(PR_CAPBSET_READ, i);
if (ret < 0)
perror("prctl");
else if (ret==1)
printf("%s%s", (comma++) ? ", " : " ", captable[i]);
}
printf("\n");
return 0;
}

int capdrop(char *str)
{
unsigned long i;

int found=0;
for (i=0; i<numcaps; i++) {
if (strcmp(captable[i], str) == 0) {
found=1;
break;
}
}
if (!found)
return 1;
if (prctl(PR_CAPBSET_DROP, i)) {
perror("prctl");
return 1;
}
return 0;
}

int main(int argc, char *argv[])
{
if (argc<2)
return usage(argv[0]);
if (strcmp(argv[1], "get")==0)
return getbcap();
if (strcmp(argv[1], "drop")!=0 || argc<3)
return usage(argv[0]);
if (capdrop(argv[2])) {
printf("unknown capability\n");
return 1;
}
return execl("/bin/bash", "/bin/bash", NULL);
}
************************************************************

[serue@us.ibm.com: fix typo]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>a
Signed-off-by: "Serge E. Hallyn" <serue@us.ibm.com>
Tested-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[IPV4] route cache: Introduce rt_genid for smooth cache invalidation

Current ip route cache implementation is not suited to large caches.

We can consume a lot of CPU when cache must be invalidated, since we
currently need to evict all cache entries, and this eviction is
sometimes asynchronous. min_delay & max_delay can somewhat control this
asynchronism behavior, but whole thing is a kludge, regularly triggering
infamous soft lockup messages. When entries are still in use, this also
consumes a lot of ram, filling dst_garbage.list.

A better scheme is to use a generation identifier on each entry,
so that cache invalidation can be performed by changing the table
identifier, without having to scan all entries.
No more delayed flushing, no more stalling when secret_interval expires.

Invalidated entries will then be freed at GC time (controled by
ip_rt_gc_timeout or stress), or when an invalidated entry is found
in a chain when an insert is done.
Thus we keep a normal equilibrium.

This patch :
- renames rt_hash_rnd to rt_genid (and makes it an atomic_t)
- Adds a new rt_genid field to 'struct rtable' (filling a hole on 64bit)
- Checks entry->rt_genid at appropriate places :

sysctl: Infrastructure for per namespace sysctls

This patch implements the basic infrastructure for per namespace sysctls.

A list of lists of sysctl headers is added, allowing each namespace to have
it's own list of sysctl headers.

Each list of sysctl headers has a lookup function to find the first
sysctl header in the list, allowing the lists to have a per namespace
instance.

register_sysct_root is added to tell sysctl.c about additional
lists of sysctl_headers. As all of the users are expected to be in
kernel no unregister function is provided.

sysctl_head_next is updated to walk through the list of lists.

__register_sysctl_paths is added to add a new sysctl table on
a non-default sysctl list.

The only intrusive part of this patch is propagating the information
to decided which list of sysctls to use for sysctl_check_table.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Daniel Lezcano <dlezcano@fr.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: Remember the ctl_table we passed to register_sysctl_paths

By doing this we allow users of register_sysctl_paths that build
and dynamically allocate their ctl_table to be simpler. This allows
them to just remember the ctl_table_header returned from
register_sysctl_paths from which they can now find the
ctl_table array they need to free.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Daniel Lezcano <dlezcano@fr.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

sysctl: Add register_sysctl_paths function

There are a number of modules that register a sysctl table
somewhere deeply nested in the sysctl hierarchy, such as
fs/nfs, fs/xfs, dev/cdrom, etc.

They all specify several dummy ctl_tables for the path name.
This patch implements register_sysctl_path that takes
an additional path name, and makes up dummy sysctl nodes
for each component.

This patch was originally written by Olaf Kirch and
brought to my attention and reworked some by Olaf Hering.
I have changed a few additional things so the bugs are mine.

After converting all of the easy callers Olaf Hering observed
allyesconfig ARCH=i386, the patch reduces the final binary size by 9369 bytes.

.text +897
.data -7008

text data bss dec hex filename
26959310 4045899 4718592 35723801 2211a19 ../vmlinux-vanilla
26960207 4038891 4718592 35717690 221023a ../O-allyesconfig/vmlinux

So this change is both a space savings and a code simplification.

CC: Olaf Kirch <okir@suse.de>
CC: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Daniel Lezcano <dlezcano@fr.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

[S390] appldata: remove unused binary sysctls.

Remove binary sysctls that never worked due to missing strategy functions.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] cmm: remove unused binary sysctls.

Remove binary sysctls that never worked due to missing strategy functions.

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

sysctl: Error on bad sysctl tables

After going through the kernels sysctl tables several times it has become
clear that code review and testing is just not effective in prevent
problematic sysctl tables from being used in the stable kernel. I certainly
can't seem to fix the problems as fast as they are introduced.

Therefore this patch adds sysctl_check_table which is called when a sysctl
table is registered and checks to see if we have a problematic sysctl table.

The biggest part of the code is the table of valid binary sysctl entries, but
since we have frozen our set of binary sysctls this table should not need to
change, and it makes it much easier to detect when someone unintentionally
adds a new binary sysctl value.

As best as I can determine all of the several hundred errors spewed on boot up
now are legitimate.

[bunk@kernel.org: kernel/sysctl_check.c must #include <linux/string.h>]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: properly register the irda binary sysctl numbers

Grumble. These numbers should have been in sysctl.h from the beginning if we
ever expected anyone to use them. Oh well put them there now so we can find
them and make maintenance easier.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl: Factor out sysctl_data.

There as been no easy way to wrap the default sysctl strategy routine except
for returning 0. Which is not always what we want. The few instances I have
seen that want different behaviour have written their own version of
sysctl_data. While not too hard it is unnecessary code and has the potential
for extra bugs.

So to make these situations easier and make that part of sysctl more symetric
I have factord sysctl_data out of do_sysctl_strategy and exported as a
function everyone can use.

Further having sysctl_data be an explicit function makes checking for badly
formed sysctl tables much easier.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysctl core: Stop using the unnecessary ctl_table typedef

In sysctl.h the typedef struct ctl_table ctl_table violates coding style isn't
needed and is a bit of a nuisance because it makes it harder to recognize
ctl_table is a type name.

So this patch removes it from the generic sysctl code. Hopefully I will have
enough energy to send the rest of my patches will follow and to remove it from
the rest of the kernel.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add CTL_PROC back

commit eab03ac7bd3e0da99eb9dc068772a85a5e3f3577 aka
"[PATCH] Get rid of /proc/sys/proc" was good commit except strace(1) compile
breakage it introduced:

system.c:1581: error: 'CTL_PROC' undeclared here (not in a function)

So, add dummy enum back.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[NETFILTER]: bridge-nf: filter bridged IPv4/IPv6 encapsulated in pppoe traffic

The attached patch by Michael Milner adds support for using iptables and
ip6tables on bridged traffic encapsulated in ppoe frames, similar to
what's already supported for vlan.

Signed-off-by: Michael Milner <milner@blissisland.ca>
Signed-off-by: Bart De Schuymer <bdschuym@pandora.be>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Replace CONFIG_NET_DEBUG with sysctl.

Covert network warning messages from a compile time to runtime choice.
Removes kernel config option and replaces it with new /proc/sys/net/core/warnings.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: Add two new spurious RTO responses to FRTO

New sysctl tcp_frto_response is added to select amongst these
responses:
- Rate halving based; reuses CA_CWR state (default)
- Very conservative; used to be the only one available (=1)
- Undo cwr; undoes ssthresh and cwnd reductions (=2)

The response with rate halving requires a new parameter to
tcp_enter_cwr because FRTO has already reduced ssthresh and
doing a second reduction there has to be prevented. In addition,
to keep things nice on 80 cols screen, a local variable was
added.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: Add RFC3742 Limited Slow-Start, controlled by variable sysctl_tcp_max_ssthresh.

Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: Disallow RH0 by default.

A security issue is emerging. Disallow Routing Header Type 0 by default
as we have been doing for IPv4.
Note: We allow RH2 by default because it is harmless.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] sysctl: remove the proc_dir_entry member for the sysctl tables

It isn't needed anymore, all of the users are gone, and all of the ctl_table
initializers have been converted to use explicit names of the fields they are
initializing.

[akpm@osdl.org: NTFS fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: add a parent entry to ctl_table and set the parent entry

Add a parent entry into the ctl_table so you can walk the list of parents and
find the entire path to a ctl_table entry.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: reimplement the sysctl proc support

With this change the sysctl inodes can be cached and nothing needs to be done
when removing a sysctl table.

For a cost of 2K code we will save about 4K of static tables (when we remove
de from ctl_table) and 70K in proc_dir_entries that we will not allocate, or
about half that on a 32bit arch.

The speed feels about the same, even though we can now cache the sysctl
dentries :(

We get the core advantage that we don't need to have a 1 to 1 mapping between
ctl table entries and proc files. Making it possible to have /proc/sys vary
depending on the namespace you are in. The currently merged namespaces don't
have an issue here but the network namespace under /proc/sys/net needs to have
different directories depending on which network adapters are visible. By
simply being a cache different directories being visible depending on who you
are is trivial to implement.

[akpm@osdl.org: fix uninitialised var]
[akpm@osdl.org: fix ARM build]
[bunk@stusta.de: make things static]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: allow sysctl_perm to be called from outside of sysctl.c

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: factor out sysctl_head_next from do_sysctl

The current logic to walk through the list of sysctl table headers is slightly
painful and implement in a way it cannot be used by code outside sysctl.c

I am in the process of implementing a version of the sysctl proc support that
instead of using the proc generic non-caching monster, just uses the existing
sysctl data structure as backing store for building the dcache entries and for
doing directory reads. To use the existing data structures however I need a
way to get at them.

[akpm@osdl.org: warning fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: remove insert_at_head from register_sysctl

The semantic effect of insert_at_head is that it would allow new registered
sysctl entries to override existing sysctl entries of the same name. Which is
pain for caching and the proc interface never implemented.

I have done an audit and discovered that none of the current users of
register_sysctl care as (excpet for directories) they do not register
duplicate sysctl entries.

So this patch simply removes the support for overriding existing entries in
the sys_sysctl interface since no one uses it or cares and it makes future
enhancments harder.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: remove support for CTL_ANY

There are currently no users in the kernel for CTL_ANY and it only has effect
on the binary interface which is practically unused.

So this complicates sysctl lookups for no good reason so just remove it.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: register the ocfs2 sysctl numbers

ocfs2 was did not have the binary number it uses under CTL_FS registered in
sysctl.h. Register it to avoid future conflicts, and change the name of the
definition to be in line with the rest of the sysctl numbers.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: register the sysctl number used by the arlan driver

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: s390: move sysctl definitions to sysctl.h

We need to have the the definition of all top level sysctl directories
registers in sysctl.h so we don't conflict by accident and cause abi problems.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: move CTL_FRV into sysctl.h where it belongs

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: move CTL_PM into sysctl.h where it belongs

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] sysctl: move CTL_SUNRPC to sysctl.h where it belongs

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[X.25]: Adds /proc/sys/net/x25/x25_forward to control forwarding.

echo "1" > /proc/sys/net/x25/x25_forward
To turn on x25_forwarding, defaults to off
Requires the previous patch.

Signed-off-by: Andrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove duplicate "have to" in comment

Introduced in commit 7cc13edc139108bb527b692f0548dce6bc648572.

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

[PATCH] sysctl: remove unused "context" param

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[DCCP]: Remove allocation of sysctl numbers

This is in response to a request sent earlier by Eric W. Biederman
and replaces all sysctl numbers for net.dccp.default with CTL_UNNUMBERED.

It has been tested to compile and to work.

Commiter note: I've removed the use of CTL_UNNUMBERED, not setting .ctl_name
sets it to 0, that is the what CTL_UNNUMBERED is, reason is
to avoid unneeded source code cluttering.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[DCCP]: Adds the tx buffer sysctls

This one got lost on the way from Ian to Gerrit to me, fix it.

Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[DCCP]: Add sysctls to control retransmission behaviour

This adds 3 sysctls which govern the retransmission behaviour of DCCP control
packets (3way handshake, feature negotiation).

It removes 4 FIXMEs from the code.

The close resemblance of sysctl variables to their TCP analogues is emphasised
not only by their name, but also by giving them the same initial values.
This is useful since there is not much practical experience with DCCP yet.

Furthermore, with regard to the previous patch, it is now possible to limit
the number of keepalive-Responses by setting net.dccp.default.request_retries
(also a bit like in TCP).

Lastly, added documentation of all existing DCCP sysctls.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[TCP]: Restrict congestion control choices.

Allow normal users to only choose among a restricted set of congestion
control choices. The default is reno and what ever has been configured
as default. But the policy can be changed by administrator at any time.

For example, to allow any choice:
cp /proc/sys/net/ipv4/tcp_available_congestion_control \
/proc/sys/net/ipv4/tcp_allowed_congestion_control

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: Add tcp_available_congestion_control sysctl.

Create /proc/sys/net/ipv4/tcp_available_congestion_control
that reflects currently available TCP choices.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] sysctl: implement CTL_UNNUMBERED

This patch takes the CTL_UNNUMBERD concept from NFS and makes it available to
all new sysctl users.

At the same time the sysctl binary interface maintenance documentation is
updated to mention and to describe what is needed to successfully maintain the
sysctl binary interface.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] sysctl: allow a zero ctl_name in the middle of a sysctl table

Since it is becoming clear that there are just enough users of the binary
sysctl interface that completely removing the binary interface from the kernel
will not be an option for foreseeable future, we need to find a way to address
the sysctl maintenance issues.

The basic problem is that sysctl requires one central authority to allocate
sysctl numbers, or else conflicts and ABI breakage occur. The proc interface
to sysctl does not have that problem, as names are not densely allocated.

By not terminating a sysctl table until I have neither a ctl_name nor a
procname, it becomes simple to add sysctl entries that don't show up in the
binary sysctl interface. Which allows people to avoid allocating a binary
sysctl value when not needed.

I have audited the kernel code and in my reading I have not found a single
sysctl table that wasn't terminated by a completely zero filled entry. So
this change in behavior should not affect anything.

I think this mechanism eases the pain enough that combined with a little
disciple we can solve the reoccurring sysctl ABI breakage.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] zone_reclaim: dynamic slab reclaim

Currently one can enable slab reclaim by setting an explicit option in
/proc/sys/vm/zone_reclaim_mode. Slab reclaim is then used as a final
option if the freeing of unmapped file backed pages is not enough to free
enough pages to allow a local allocation.

However, that means that the slab can grow excessively and that most memory
of a node may be used by slabs. We have had a case where a machine with
46GB of memory was using 40-42GB for slab. Zone reclaim was effective in
dealing with pagecache pages. However, slab reclaim was only done during
global reclaim (which is a bit rare on NUMA systems).

This patch implements slab reclaim during zone reclaim. Zone reclaim
occurs if there is a danger of an off node allocation. At that point we

1. Shrink the per node page cache if the number of pagecache
pages is more than min_unmapped_ratio percent of pages in a zone.

2. Shrink the slab cache if the number of the nodes reclaimable slab pages
(patch depends on earlier one that implements that counter)
are more than min_slab_ratio (a new /proc/sys/vm tunable).

The shrinking of the slab cache is a bit problematic since it is not node
specific. So we simply calculate what point in the slab we want to reach
(current per node slab use minus the number of pages that neeed to be
allocated) and then repeately run the global reclaim until that is
unsuccessful or we have reached the limit. I hope we will have zone based
slab reclaim at some point which will make that easier.

The default for the min_slab_ratio is 5%

Also remove the slab option from /proc/sys/vm/zone_reclaim_mode.

[akpm@osdl.org: cleanups]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] x86: Allow users to force a panic on NMI

To quote Alan Cox:

The default Linux behaviour on an NMI of either memory or unknown is to
continue operation. For many environments such as scientific computing
it is preferable that the box is taken out and the error dealt with than
an uncorrected parity/ECC error get propogated.

A small number of systems do generate NMI's for bizarre random reasons
such as power management so the default is unchanged. In other respects
the new proc/sys entry works like the existing panic controls already in
that directory.

This is separate to the edac support - EDAC allows supported chipsets to
handle ECC errors well, this change allows unsupported cases to at least
panic rather than cause problems further down the line.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>

[PATCH] x86: Add abilty to enable/disable nmi watchdog with sysctl

Adds a new /proc/sys/kernel/nmi call that will enable/disable the nmi
watchdog.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>

[IPV6] NDISC: Add proxy_ndp sysctl.

We do not always need proxy NDP functionality even we
enable forwarding.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NetLabel]: CIPSOv4 engine

Add support for the Commercial IP Security Option (CIPSO) to the IPv4
network stack. CIPSO has become a de-facto standard for
trusted/labeled networking amongst existing Trusted Operating Systems
such as Trusted Solaris, HP-UX CMW, etc. This implementation is
designed to be used with the NetLabel subsystem to provide explicit
packet labeling to LSM developers.

The CIPSO/IPv4 packet labeling works by the LSM calling a NetLabel API
function which attaches a CIPSO label (IPv4 option) to a given socket;
this in turn attaches the CIPSO label to every packet leaving the
socket without any extra processing on the outbound side. On the
inbound side the individual packet's sk_buff is examined through a
call to a NetLabel API function to determine if a CIPSO/IPv4 label is
present and if so the security attributes of the CIPSO label are
returned to the caller of the NetLabel API function.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] ZVC/zone_reclaim: Leave 1% of unmapped pagecache pages for file I/O

It turns out that it is advantageous to leave a small portion of unmapped file
backed pages if all of a zone's pages (or almost all pages) are allocated and
so the page allocator has to go off-node.

This allows recently used file I/O buffers to stay on the node and
reduces the times that zone reclaim is invoked if file I/O occurs
when we run out of memory in a zone.

The problem is that zone reclaim runs too frequently when the page cache is
used for file I/O (read write and therefore unmapped pages!) alone and we have
almost all pages of the zone allocated. Zone reclaim may remove 32 unmapped
pages. File I/O will use these pages for the next read/write requests and the
unmapped pages increase. After the zone has filled up again zone reclaim will
remove it again after only 32 pages. This cycle is too inefficient and there
are potentially too many zone reclaim cycles.

With the 1% boundary we may still remove all unmapped pages for file I/O in
zone reclaim pass. However. it will take a large number of read and writes
to get back to 1% again where we trigger zone reclaim again.

The zone reclaim 2.6.16/17 does not show this behavior because we have a 30
second timeout.

[akpm@osdl.org: rename the /proc file and the variable]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] pi-futex: rt mutex core

Core functions for the rt-mutex subsystem.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] vdso: randomize the i386 vDSO by moving it into a vma

Move the i386 VDSO down into a vma and thus randomize it.

Besides the security implications, this feature also helps debuggers, which
can COW a vma-backed VDSO just like a normal DSO and can thus do
single-stepping and other debugging features.

It's good for hypervisors (Xen, VMWare) too, which typically live in the same
high-mapped address space as the VDSO, hence whenever the VDSO is used, they
get lots of guest pagefaults and have to fix such guest accesses up - which
slows things down instead of speeding things up (the primary purpose of the
VDSO).

There's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support
for older glibcs that still rely on a prelinked high-mapped VDSO. Newer
distributions (using glibc 2.3.3 or later) can turn this option off. Turning
it off is also recommended for security reasons: attackers cannot use the
predictable high-mapped VDSO page as syscall trampoline anymore.

There is a new vdso=[0|1] boot option as well, and a runtime
/proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO to be turned
on/off.

(This version of the VDSO-randomization patch also has working ELF
coredumping, the previous patch crashed in the coredumping code.)

This code is a combined work of the exec-shield VDSO randomization
code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell
started this patch and i completed it.

[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] x86_64: Add compat_printk and sysctl to turn off compat layer warnings

Sometimes e.g. with crashme the compat layer warnings can be noisy.
Add a way to turn them off by gating all output through compat_printk
that checks a global sysctl. The default is not changed.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Get rid of /proc/sys/proc

The table is empty, why does it still exist?

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] support for panic at OOM

This patch adds panic_on_oom sysctl under sys.vm.

When sysctl vm.panic_on_oom = 1, the kernel panics intead of killing rogue
processes. And if vm.panic_on_oom is 0 the kernel will do oom_kill() in
the same way as it does today. Of course, the default value is 0 and only
root can modifies it.

In general, oom_killer works well and kill rogue processes. So the whole
system can survive. But there are environments where panic is preferable
rather than kill some processes.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[TCP]: Add tcp_slow_start_after_idle sysctl.

A lot of people have asked for a way to disable tcp_cwnd_restart(),
and it seems reasonable to add a sysctl to do that.

Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: conntrack: add sysctl to disable checksumming

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[I/OAT]: Add a sysctl for tuning the I/OAT offloaded I/O threshold

Any socket recv of less than this ammount will not be offloaded

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: sysctl to allow TCP window > 32767 sans wscale

Back in the dark ages, we had to be conservative and only allow 15-bit
window fields if the window scale option was not negotiated. Some
ancient stacks used a signed 16-bit quantity for the window field of
the TCP header and would get confused.

Those days are long gone, so we can use the full 16-bits by default
now.

There is a sysctl added so that we can still interact with such old
stacks

Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV4] ARP: Alloc acceptance of unsolicited ARP via netdevice sysctl.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[DCCP] feat: Introduce sysctls for the default features

[root@qemu ~]# for a in /proc/sys/net/dccp/default/* ; do echo $a ; cat $a ; done
/proc/sys/net/dccp/default/ack_ratio
2
/proc/sys/net/dccp/default/rx_ccid
3
/proc/sys/net/dccp/default/send_ackvec
1
/proc/sys/net/dccp/default/send_ndp
1
/proc/sys/net/dccp/default/seq_window
100
/proc/sys/net/dccp/default/tx_ccid
3
[root@qemu ~]#

So if wanting to test ccid3 as the tx CCID one can just do:

[root@qemu ~]# echo 3 > /proc/sys/net/dccp/default/tx_ccid
[root@qemu ~]# echo 2 > /proc/sys/net/dccp/default/rx_ccid
[root@qemu ~]# cat /proc/sys/net/dccp/default/[tr]x_ccid
2
3
[root@qemu ~]#

Of course we also need the setsockopt for each app to tell its preferences, but
for testing or defining something other than CCID2 as the default for apps that
don't explicitely set their preference the sysctl interface is handy.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPSEC]: Sync series - core changes

This patch provides the core functionality needed for sync events
for ipsec. Derived work of Krisztian KOVACS <hidden@balabit.hu>

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: MTU probing

Implementation of packetization layer path mtu discovery for TCP, based on
the internet-draft currently found at
<http://www.ietf.org/internet-drafts/draft-ietf-pmtud-method-05.txt>.

Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: ROUTE: Add accept_ra_rt_info_max_plen sysctl.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: ROUTE: Add router_probe_interval sysctl.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: ROUTE: Add accept_ra_rtr_pref sysctl.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: ADDRCONF: Add accept_ra_pinfo sysctl.

This controls whether we accept Prefix Information in RAs.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: ROUTE: Add accept_ra_defrtr sysctl.

This controls whether we accept default router information
in RAs.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IA64] sysctl option to silence unaligned trap warnings

Allow sysadmin to disable all warnings about userland apps
making unaligned accesses by using:
# echo 1 > /proc/sys/kernel/ignore-unaligned-usertrap
Rather than having to use prctl on a process by process basis.

Default behaivour leaves the warnings enabled.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

[PATCH] suspend-to-ram: allow video options to be set at runtime

Currently, acpi video options can only be set on kernel command line. That's
little inflexible; I'd like userland s2ram application that just works, and
modifying kernel command line according to whitelist is not fun. It is better
to just allow s2ram application to set video options just before suspend
(according to the whitelist).

This implements sysctl to allow setting suspend video options without reboot.

(akpm: Documentation updates for this new sysctl are pending..)

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: "Brown, Len" <len.brown@intel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] zone_reclaim: configurable off node allocation period.

Currently the zone_reclaim code has a fixed window of 30 seconds of off node
allocations should a local zone have no unused pagecache pages left. Reclaim
will be attempted again after this timeout period to avoid repeated useless
scans for memory. This is also useful to established sufficiently large off
node allocation chunks to relieve the local node.

It may be beneficial to adjust that time period for some special situations.
For example if memory use was exceeding node capacity one may want to give up
for longer periods of time. If memory spikes intermittendly then one may want
to shorten the time period to reduce the number of off node allocations.

This patch allows just that....

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Zone reclaim: proc override

proc support for zone reclaim

This patch creates a proc entry /proc/sys/vm/zone_reclaim_mode that may be
used to override the automatic determination of the zone reclaim made on
bootup.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Make high and batch sizes of per_cpu_pagelists configurable

As recently there has been lot of traffic on the right values for batch and
high water marks for per_cpu_pagelists. This patch makes these two
variables configurable through /proc interface.

A new tunable /proc/sys/vm/percpu_pagelist_fraction is added. This entry
controls the fraction of pages at most in each zone that are allocated for
each per cpu page list. The min value for this is 8. It means that we
don't allow more than 1/8th of pages in each zone to be allocated in any
single per_cpu_pagelist.

The batch value of each per cpu pagelist is also updated as a result. It
is set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8)

Signed-off-by: Rohit Seth <rohit.seth@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] drop-pagecache

Add /proc/sys/vm/drop_caches. When written to, this will cause the kernel to
discard as much pagecache and/or reclaimable slab objects as it can. THis
operation requires root permissions.

It won't drop dirty data, so the user should run `sync' first.

Caveats:

a) Holds inode_lock for exorbitant amounts of time.

b) Needs to be taught about NUMA nodes: propagate these all the way through
so the discarding can be controlled on a per-node basis.

This is a debugging feature: useful for getting consistent results between
filesystem benchmarks. We could possibly put it under a config option, but
it's less than 300 bytes.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] driver core: replace "hotplug" by "uevent"

Leave the overloaded "hotplug" word to susbsystems which are handling
real devices. The driver core does not "plug" anything, it just exports
the state to userspace and generates events.

Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[IPV4]: Safer reassembly

Another spin of Herbert Xu's "safer ip reassembly" patch
for 2.6.16.

(The original patch is here:
http://marc.theaimsgroup.com/?l=linux-netdev&m=112281936522415&w=2
and my only contribution is to have tested it.)

This patch (optionally) does additional checks before accepting IP
fragments, which can greatly reduce the possibility of reassembling
fragments which originated from different IP datagrams.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arthur Kepner <akepner@sgi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[DECNET]: add memory buffer settings

The patch (originally from Steve) simply adds memory buffer settings to
DECnet similar to those in TCP.

Signed-off-by: Patrick Caulfield <patrick@tykepenguin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] Make sysctl.h (again) usable from userspace

Make sysctl.h (again) useable from userspace

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[SCTP]: Include ulpevents in socket receive buffer accounting.

Also introduces a sysctl option to configure the receive buffer
accounting policy to be either at socket or association level.
Default is all the associations on the same socket share the
receive buffer.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: Appropriate Byte Count support

This is an updated version of the RFC3465 ABC patch originally
for Linux 2.6.11-rc4 by Yee-Ting Li. ABC is a way of counting
bytes ack'd rather than packets when updating congestion control.

The orignal ABC described in the RFC applied to a Reno style
algorithm. For advanced congestion control there is little
change after leaving slow start.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Add nf_conntrack subsystem.

The existing connection tracking subsystem in netfilter can only
handle ipv4. There were basically two choices present to add
connection tracking support for ipv6. We could either duplicate all
of the ipv4 connection tracking code into an ipv6 counterpart, or (the
choice taken by these patches) we could design a generic layer that
could handle both ipv4 and ipv6 and thus requiring only one sub-protocol
(TCP, UDP, etc.) connection tracking helper module to be written.

In fact nf_conntrack is capable of working with any layer 3
protocol.

The existing ipv4 specific conntrack code could also not deal
with the pecularities of doing connection tracking on ipv6,
which is also cured here. For example, these issues include:

1) ICMPv6 handling, which is used for neighbour discovery in
ipv6 thus some messages such as these should not participate
in connection tracking since effectively they are like ARP
messages

2) fragmentation must be handled differently in ipv6, because
the simplistic "defrag, connection track and NAT, refrag"
(which the existing ipv4 connection tracking does) approach simply
isn't feasible in ipv6

3) ipv6 extension header parsing must occur at the correct spots
before and after connection tracking decisions, and there were
no provisions for this in the existing connection tracking
design

4) ipv6 has no need for stateful NAT

The ipv4 specific conntrack layer is kept around, until all of
the ipv4 specific conntrack helpers are ported over to nf_conntrack
and it is feature complete. Once that occurs, the old conntrack
stuff will get placed into the feature-removal-schedule and we will
fully kill it off 6 months later.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[PATCH] Fix sysctl unregistration oops (CVE-2005-2709)

You could open the /proc/sys/net/ipv4/conf/<if>/<whatever> file, then
wait for interface to go away, try to grab as much memory as possible in
hope to hit the (kfreed) ctl_table. Then fill it with pointers to your
function. Then do read from file you've opened and if you are lucky,
you'll get it called as ->proc_handler() in kernel mode.

So this is at least an Oops and possibly more. It does depend on an
interface going away though, so less of a security risk than it would
otherwise be.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[LLC]: Add sysctl support for the LLC timeouts

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

[NETROM]: Implement G8PZT Circuit reset for NET/ROM

NET/ROM is lacking a connection reset like TCP's RST flag which at times
may result in a connecting having to slowly timing out instead of just being
reset. An earlier attempt to reset the connection by sending a
NR_CONNACK | NR_CHOKE_FLAG transport was inacceptable as it did result in
crashes of BPQ systems. An alternative approach of introducing a new
transport type 7 (NR_RESET) has be implemented several years ago in
Paula Jayne Dowie G8PZT's Xrouter.

Implement NR_RESET for Linux's NET/ROM but like any messing with the state
engine consider this experimental for now and thus control it by a sysctl
(net.netrom.reset) which for the time being defaults to off.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] ipmi poweroff: fix chassis control

The IPMI power control function proc_write_chassctrl was badly written, it
directly used userspace pointers, it assumed that strings were NULL
terminated, and it used the evil sscanf function. This converts over to
using the sysctl interface for this data and changes the semantics to be a
little more logical.

Signed-off-by: Corey Minyard <minyard@acm.org>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: spin lock retry

Split spin lock and r/w lock implementation into a single try which is done
inline and an out of line function that repeatedly tries to get the lock
before doing the cpu_relax(). Add a system control to set the number of
retries before a cpu is yielded.

The reason for the spin lock retry is that the diagnose 0x44 that is used to
give up the virtual cpu is quite expensive. For spin locks that are held only
for a short period of time the costs of the diagnoses outweights the savings
for spin locks that are held for a longer timer. The default retry count is
1000.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] inotify: move sysctl

This moves the inotify sysctl knobs to "/proc/sys/fs/inotify" from
"/proc/sys/fs". Also some related cleanup.

Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] inotify

inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:

* dnotify requires the opening of one fd per each directory
that you intend to watch. This quickly results in too many
open files and pins removable media, preventing unmount.
* dnotify is directory-based. You only learn about changes to
directories. Sure, a change to a file in a directory affects
the directory, but you are then forced to keep a cache of
stat structures.
* dnotify's interface to user-space is awful. Signals?

inotify provides a more usable, simple, powerful solution to file change
notification:

* inotify's interface is a system call that returns a fd, not SIGIO.
You get a single fd, which is select()-able.
* inotify has an event that says "the filesystem that the item
you were watching is on was unmounted."
* inotify can watch directories or files.

Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.

See Documentation/filesystems/inotify.txt.

Signed-off-by: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[SCTP] Make init & delayed sack timeouts configurable by user.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Separate two usages of netdev_max_backlog.

Separate out the two uses of netdev_max_backlog. One controls the
upper bound on packets processed per softirq, the new name for this is
netdev_budget; the other controls the limit on packets queued via
netif_rx.

Increase the max_backlog default to account for faster processors.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: Add pluggable congestion control algorithm infrastructure.

Allow TCP to have multiple pluggable congestion control algorithms.
Algorithms are defined by a set of operations and can be built in
or modules. The legacy "new RENO" algorithm is used as a starting
point and fallback.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] setuid core dump

Add a new `suid_dumpable' sysctl:

This value can be used to query and set the core dump mode for setuid
or otherwise protected/tainted binaries. The modes are

0 - (default) - traditional behaviour. Any process which has changed
privilege levels or is execute only will not be dumped

1 - (debug) - all processes dump core when possible. The core dump is
owned by the current user and no security is applied. This is intended
for system debugging situations only. Ptrace is unchecked.

2 - (suidsafe) - any binary which normally would not be dumped is dumped
readable by root only. This allows the end user to remove such a dump but
not access it directly. For security reasons core dumps in this mode will
not overwrite one another or other files. This mode is appropriate when
adminstrators are attempting to debug problems in a normal environment.

(akpm:

> > +EXPORT_SYMBOL(suid_dumpable);
>
> EXPORT_SYMBOL_GPL?

No problem to me.

> > if (current->euid == current->uid && current->egid == current->gid)
> > current->mm->dumpable = 1;
>
> Should this be SUID_DUMP_USER?

Actually the feedback I had from last time was that the SUID_ defines
should go because its clearer to follow the numbers. They can go
everywhere (and there are lots of places where dumpable is tested/used
as a bool in untouched code)

> Maybe this should be renamed to `dump_policy' or something. Doing that
> would help us catch any code which isn't using the #defines, too.

Fair comment. The patch was designed to be easy to maintain for Red Hat
rather than for merging. Changing that field would create a gigantic
diff because it is used all over the place.

)

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[IPV4]: Sysctl configurable icmp error source address.

This patch alows you to change the source address of icmp error
messages. It applies cleanly to 2.6.11.11 and retains the default
behaviour.

In the old (default) behaviour icmp error messages are sent with the ip
of the exiting interface.

The new behaviour (when the sysctl variable is toggled on), it will send
the message with the ip of the interface that received the packet that
caused the icmp error. This is the behaviour network administrators will
expect from a router. It makes debugging complicated network layouts
much easier. Also, all 'vendor routers' I know of have the later
behaviour.

Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV4]: Primary and secondary addresses

Add an option to make secondary IP addresses get promoted
when primary IP addresses are removed from the device.
It defaults to off to preserve existing behavior.

Signed-off-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[SCTP] Fix SCTP sendbuffer accouting.

- Include chunk and skb sizes in sendbuffer accounting.
- 2 policies are supported. 0: per socket accouting, 1: per association
accounting

DaveM: I've made the default per-socket.

Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!