mm, treewide: rename kzfree() to kfree_sensitive()

As said by Linus:

A symmetric naming is only helpful if it implies symmetries in use.
Otherwise it's actively misleading.

In "kzalloc()", the z is meaningful and an important part of what the
caller wants.

In "kzfree()", the z is actively detrimental, because maybe in the
future we really _might_ want to use that "memfill(0xdeadbeef)" or
something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

git grep -w --name-only kzfree |\
xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KEYS: Don't write out to userspace while holding key semaphore

A lockdep circular locking dependency report was seen when running a
keyutils test:

[12537.027242] ======================================================
[12537.059309] WARNING: possible circular locking dependency detected
[12537.088148] 4.18.0-147.7.1.el8_1.x86_64+debug #1 Tainted: G OE --------- - -
[12537.125253] ------------------------------------------------------
[12537.153189] keyctl/25598 is trying to acquire lock:
[12537.175087] 000000007c39f96c (&mm->mmap_sem){++++}, at: __might_fault+0xc4/0x1b0
[12537.208365]
[12537.208365] but task is already holding lock:
[12537.234507] 000000003de5b58d (&type->lock_class){++++}, at: keyctl_read_key+0x15a/0x220
[12537.270476]
[12537.270476] which lock already depends on the new lock.
[12537.270476]
[12537.307209]
[12537.307209] the existing dependency chain (in reverse order) is:
[12537.340754]
[12537.340754] -> #3 (&type->lock_class){++++}:
[12537.367434] down_write+0x4d/0x110
[12537.385202] __key_link_begin+0x87/0x280
[12537.405232] request_key_and_link+0x483/0xf70
[12537.427221] request_key+0x3c/0x80
[12537.444839] dns_query+0x1db/0x5a5 [dns_resolver]
[12537.468445] dns_resolve_server_name_to_ip+0x1e1/0x4d0 [cifs]
[12537.496731] cifs_reconnect+0xe04/0x2500 [cifs]
[12537.519418] cifs_readv_from_socket+0x461/0x690 [cifs]
[12537.546263] cifs_read_from_socket+0xa0/0xe0 [cifs]
[12537.573551] cifs_demultiplex_thread+0x311/0x2db0 [cifs]
[12537.601045] kthread+0x30c/0x3d0
[12537.617906] ret_from_fork+0x3a/0x50
[12537.636225]
[12537.636225] -> #2 (root_key_user.cons_lock){+.+.}:
[12537.664525] __mutex_lock+0x105/0x11f0
[12537.683734] request_key_and_link+0x35a/0xf70
[12537.705640] request_key+0x3c/0x80
[12537.723304] dns_query+0x1db/0x5a5 [dns_resolver]
[12537.746773] dns_resolve_server_name_to_ip+0x1e1/0x4d0 [cifs]
[12537.775607] cifs_reconnect+0xe04/0x2500 [cifs]
[12537.798322] cifs_readv_from_socket+0x461/0x690 [cifs]
[12537.823369] cifs_read_from_socket+0xa0/0xe0 [cifs]
[12537.847262] cifs_demultiplex_thread+0x311/0x2db0 [cifs]
[12537.873477] kthread+0x30c/0x3d0
[12537.890281] ret_from_fork+0x3a/0x50
[12537.908649]
[12537.908649] -> #1 (&tcp_ses->srv_mutex){+.+.}:
[12537.935225] __mutex_lock+0x105/0x11f0
[12537.954450] cifs_call_async+0x102/0x7f0 [cifs]
[12537.977250] smb2_async_readv+0x6c3/0xc90 [cifs]
[12538.000659] cifs_readpages+0x120a/0x1e50 [cifs]
[12538.023920] read_pages+0xf5/0x560
[12538.041583] __do_page_cache_readahead+0x41d/0x4b0
[12538.067047] ondemand_readahead+0x44c/0xc10
[12538.092069] filemap_fault+0xec1/0x1830
[12538.111637] __do_fault+0x82/0x260
[12538.129216] do_fault+0x419/0xfb0
[12538.146390] __handle_mm_fault+0x862/0xdf0
[12538.167408] handle_mm_fault+0x154/0x550
[12538.187401] __do_page_fault+0x42f/0xa60
[12538.207395] do_page_fault+0x38/0x5e0
[12538.225777] page_fault+0x1e/0x30
[12538.243010]
[12538.243010] -> #0 (&mm->mmap_sem){++++}:
[12538.267875] lock_acquire+0x14c/0x420
[12538.286848] __might_fault+0x119/0x1b0
[12538.306006] keyring_read_iterator+0x7e/0x170
[12538.327936] assoc_array_subtree_iterate+0x97/0x280
[12538.352154] keyring_read+0xe9/0x110
[12538.370558] keyctl_read_key+0x1b9/0x220
[12538.391470] do_syscall_64+0xa5/0x4b0
[12538.410511] entry_SYSCALL_64_after_hwframe+0x6a/0xdf
[12538.435535]
[12538.435535] other info that might help us debug this:
[12538.435535]
[12538.472829] Chain exists of:
[12538.472829] &mm->mmap_sem --> root_key_user.cons_lock --> &type->lock_class
[12538.472829]
[12538.524820] Possible unsafe locking scenario:
[12538.524820]
[12538.551431] CPU0 CPU1
[12538.572654] ---- ----
[12538.595865] lock(&type->lock_class);
[12538.613737] lock(root_key_user.cons_lock);
[12538.644234] lock(&type->lock_class);
[12538.672410] lock(&mm->mmap_sem);
[12538.687758]
[12538.687758] *** DEADLOCK ***
[12538.687758]
[12538.714455] 1 lock held by keyctl/25598:
[12538.732097] #0: 000000003de5b58d (&type->lock_class){++++}, at: keyctl_read_key+0x15a/0x220
[12538.770573]
[12538.770573] stack backtrace:
[12538.790136] CPU: 2 PID: 25598 Comm: keyctl Kdump: loaded Tainted: G
[12538.844855] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 12/27/2015
[12538.881963] Call Trace:
[12538.892897] dump_stack+0x9a/0xf0
[12538.907908] print_circular_bug.isra.25.cold.50+0x1bc/0x279
[12538.932891] ? save_trace+0xd6/0x250
[12538.948979] check_prev_add.constprop.32+0xc36/0x14f0
[12538.971643] ? keyring_compare_object+0x104/0x190
[12538.992738] ? check_usage+0x550/0x550
[12539.009845] ? sched_clock+0x5/0x10
[12539.025484] ? sched_clock_cpu+0x18/0x1e0
[12539.043555] __lock_acquire+0x1f12/0x38d0
[12539.061551] ? trace_hardirqs_on+0x10/0x10
[12539.080554] lock_acquire+0x14c/0x420
[12539.100330] ? __might_fault+0xc4/0x1b0
[12539.119079] __might_fault+0x119/0x1b0
[12539.135869] ? __might_fault+0xc4/0x1b0
[12539.153234] keyring_read_iterator+0x7e/0x170
[12539.172787] ? keyring_read+0x110/0x110
[12539.190059] assoc_array_subtree_iterate+0x97/0x280
[12539.211526] keyring_read+0xe9/0x110
[12539.227561] ? keyring_gc_check_iterator+0xc0/0xc0
[12539.249076] keyctl_read_key+0x1b9/0x220
[12539.266660] do_syscall_64+0xa5/0x4b0
[12539.283091] entry_SYSCALL_64_after_hwframe+0x6a/0xdf

One way to prevent this deadlock scenario from happening is to not
allow writing to userspace while holding the key semaphore. Instead,
an internal buffer is allocated for getting the keys out from the
read method first before copying them out to userspace without holding
the lock.

That requires taking out the __user modifier from all the relevant
read methods as well as additional changes to not use any userspace
write helpers. That is,

1) The put_user() call is replaced by a direct copy.
2) The copy_to_user() call is replaced by memcpy().
3) All the fault handling code is removed.

Compiling on a x86-64 system, the size of the rxrpc_read() function is
reduced from 3795 bytes to 2384 bytes with this patch.

Fixes: ^1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

security: audit and remove any unnecessary uses of module.h

Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.

The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.

Since module.h might have been the implicit source for init.h
(for __init) and for export.h (for EXPORT_SYMBOL) we consider each
instance for the presence of either and replace as needed.

Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: linux-security-module@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: keyrings@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: James Morris <james.morris@microsoft.com>

KEYS: Fix race between updating and finding a negative key

Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection
error into one field such that:

(1) The instantiation state can be modified/read atomically.

(2) The error can be accessed atomically with the state.

(3) The error isn't stored unioned with the payload pointers.

This deals with the problem that the state is spread over three different
objects (two bits and a separate variable) and reading or updating them
atomically isn't practical, given that not only can uninstantiated keys
change into instantiated or rejected keys, but rejected keys can also turn
into instantiated keys - and someone accessing the key might not be using
any locking.

The main side effect of this problem is that what was held in the payload
may change, depending on the state. For instance, you might observe the
key to be in the rejected state. You then read the cached error, but if
the key semaphore wasn't locked, the key might've become instantiated
between the two reads - and you might now have something in hand that isn't
actually an error code.

The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error
code if the key is negatively instantiated. The key_is_instantiated()
function is replaced with key_is_positive() to avoid confusion as negative
keys are also 'instantiated'.

Additionally, barriering is included:

(1) Order payload-set before state-set during instantiation.

(2) Order state-read before payload-read when using the key.

Further separate barriering is necessary if RCU is being used to access the
payload content after reading the payload pointers.

Fixes: 146aa8b1453b ("KEYS: Merge the type-specific data with the payload data")
Cc: stable@vger.kernel.org # v4.4+
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>

KEYS: user_defined: sanitize key payloads

Zero the payloads of user and logon keys before freeing them. This
prevents sensitive key material from being kept around in the slab
caches after a key is released.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()

rcu_dereference_key() and user_key_payload() are currently being used in
two different, incompatible ways:

(1) As a wrapper to rcu_dereference() - when only the RCU read lock used
to protect the key.

(2) As a wrapper to rcu_dereference_protected() - when the key semaphor is
used to protect the key and the may be being modified.

Fix this by splitting both of the key wrappers to produce:

(1) RCU accessors for keys when caller has the key semaphore locked:

dereference_key_locked()
user_key_payload_locked()

(2) RCU accessors for keys when caller holds the RCU read lock:

dereference_key_rcu()
user_key_payload_rcu()

This should fix following warning in the NFS idmapper

===============================
[ INFO: suspicious RCU usage. ]
4.10.0 #1 Tainted: G W
-------------------------------
./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 0
1 lock held by mount.nfs/5987:
#0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4]
stack backtrace:
CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1
Call Trace:
dump_stack+0xe8/0x154 (unreliable)
lockdep_rcu_suspicious+0x140/0x190
nfs_idmap_get_key+0x380/0x420 [nfsv4]
nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4]
decode_getfattr_attrs+0xfac/0x16b0 [nfsv4]
decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4]
nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4]
rpcauth_unwrap_resp+0xe8/0x140 [sunrpc]
call_decode+0x29c/0x910 [sunrpc]
__rpc_execute+0x140/0x8f0 [sunrpc]
rpc_run_task+0x170/0x200 [sunrpc]
nfs4_call_sync_sequence+0x68/0xa0 [nfsv4]
_nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4]
nfs4_lookup_root+0xe0/0x350 [nfsv4]
nfs4_lookup_root_sec+0x70/0xa0 [nfsv4]
nfs4_find_root_sec+0xc4/0x100 [nfsv4]
nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4]
nfs4_get_rootfh+0x6c/0x190 [nfsv4]
nfs4_server_common_setup+0xc4/0x260 [nfsv4]
nfs4_create_server+0x278/0x3c0 [nfsv4]
nfs4_remote_mount+0x50/0xb0 [nfsv4]
mount_fs+0x74/0x210
vfs_kern_mount+0x78/0x220
nfs_do_root_mount+0xb0/0x140 [nfsv4]
nfs4_try_mount+0x60/0x100 [nfsv4]
nfs_fs_mount+0x5ec/0xda0 [nfs]
mount_fs+0x74/0x210
vfs_kern_mount+0x78/0x220
do_mount+0x254/0xf70
SyS_mount+0x94/0x100
system_call+0x38/0xe0

Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KEYS: user_update should use copy of payload made during preparsing

The payload preparsing routine for user keys makes a copy of the payload
provided by the caller and stashes it in the key_preparsed_payload struct for
->instantiate() or ->update() to use. However, ->update() takes another copy
of this to attach to the keyring. ->update() should be using this directly
and clearing the pointer in the preparse data.

Signed-off-by: David Howells <dhowells@redhat.com>

KEYS: Fix handling of stored error in a negatively instantiated user key

If a user key gets negatively instantiated, an error code is cached in the
payload area. A negatively instantiated key may be then be positively
instantiated by updating it with valid data. However, the ->update key
type method must be aware that the error code may be there.

The following may be used to trigger the bug in the user key type:

keyctl request2 user user "" @u
keyctl add user user "a" @u

which manifests itself as:

BUG: unable to handle kernel paging request at 00000000ffffff8a
IP: [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046
PGD 7cc30067 PUD 0
Oops: 0002 [#1] SMP
Modules linked in:
CPU: 3 PID: 2644 Comm: a.out Not tainted 4.3.0+ #49
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88003ddea700 ti: ffff88003dd88000 task.ti: ffff88003dd88000
RIP: 0010:[<ffffffff810a376f>] [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280
[<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046
RSP: 0018:ffff88003dd8bdb0 EFLAGS: 00010246
RAX: 00000000ffffff82 RBX: 0000000000000000 RCX: 0000000000000001
RDX: ffffffff81e3fe40 RSI: 0000000000000000 RDI: 00000000ffffff82
RBP: ffff88003dd8bde0 R08: ffff88007d2d2da0 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88003e8073c0 R12: 00000000ffffff82
R13: ffff88003dd8be68 R14: ffff88007d027600 R15: ffff88003ddea700
FS: 0000000000b92880(0063) GS:ffff88007fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000ffffff8a CR3: 000000007cc5f000 CR4: 00000000000006e0
Stack:
ffff88003dd8bdf0 ffffffff81160a8a 0000000000000000 00000000ffffff82
ffff88003dd8be68 ffff88007d027600 ffff88003dd8bdf0 ffffffff810a39e5
ffff88003dd8be20 ffffffff812a31ab ffff88007d027600 ffff88007d027620
Call Trace:
[<ffffffff810a39e5>] kfree_call_rcu+0x15/0x20 kernel/rcu/tree.c:3136
[<ffffffff812a31ab>] user_update+0x8b/0xb0 security/keys/user_defined.c:129
[< inline >] __key_update security/keys/key.c:730
[<ffffffff8129e5c1>] key_create_or_update+0x291/0x440 security/keys/key.c:908
[< inline >] SYSC_add_key security/keys/keyctl.c:125
[<ffffffff8129fc21>] SyS_add_key+0x101/0x1e0 security/keys/keyctl.c:60
[<ffffffff8185f617>] entry_SYSCALL_64_fastpath+0x12/0x6a arch/x86/entry/entry_64.S:185

Note the error code (-ENOKEY) in EDX.

A similar bug can be tripped by:

keyctl request2 trusted user "" @u
keyctl add trusted user "a" @u

This should also affect encrypted keys - but that has to be correctly
parameterised or it will fail with EINVAL before getting to the bit that
will crashes.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>

KEYS: Merge the type-specific data with the payload data

Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.

Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net

KEYS: Remove key_type::match in favour of overriding default by match_preparse

A previous patch added a ->match_preparse() method to the key type. This is
allowed to override the function called by the iteration algorithm.
Therefore, we can just set a default that simply checks for an exact match of
the key description with the original criterion data and allow match_preparse
to override it as needed.

The key_type::match op is then redundant and can be removed, as can the
user_match() function.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

KEYS: Remove key_type::def_lookup_type

Remove key_type::def_lookup_type as it's no longer used. The information now
defaults to KEYRING_SEARCH_LOOKUP_DIRECT but may be overridden by
type->match_preparse().

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

KEYS: Preparse match data

Preparse the match data. This provides several advantages:

(1) The preparser can reject invalid criteria up front.

(2) The preparser can convert the criteria to binary data if necessary (the
asymmetric key type really wants to do binary comparison of the key IDs).

(3) The preparser can set the type of search to be performed. This means
that it's not then a one-off setting in the key type.

(4) The preparser can set an appropriate comparator function.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

KEYS: user: Use key preparsing

Make use of key preparsing in user-defined and logon keys so that quota size
determination can take place prior to keyring locking when a key is being
added.

Also the idmapper key types need to change to match as they use the
user-defined key type routines.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>

KEYS: Introduce a search context structure

Search functions pass around a bunch of arguments, each of which gets copied
with each call. Introduce a search context structure to hold these.

Whilst we're at it, create a search flag that indicates whether the search
should be directly to the description or whether it should iterate through all
keys looking for a non-description match.

This will be useful when keyrings use a generic data struct with generic
routines to manage their content as the search terms can just be passed
through to the iterator callback function.

Also, for future use, the data to be supplied to the match function is
separated from the description pointer in the search context. This makes it
clear which is being supplied.

Signed-off-by: David Howells <dhowells@redhat.com>

KEYS: Add payload preparsing opportunity prior to key instantiate or update

Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called. This is done with the
provision of two new key type operations:

int (*preparse)(struct key_preparsed_payload *prep);
void (*free_preparse)(struct key_preparsed_payload *prep);

If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases). The second operation is called to clean up if the first
was called.

preparse() is given the opportunity to fill in the following structure:

struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};

Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.

The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.

The preparser may also propose a description for the key by attaching it as a
string to the description field. This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function. This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.

This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.

The instantiate() and update() operations are then modified to look like this:

int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
int (*update)(struct key *key, struct key_preparsed_payload *prep);

and the new payload data is passed in *prep, whether or not it was preparsed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

KEYS: Add payload preparsing opportunity prior to key instantiate or update

Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called. This is done with the
provision of two new key type operations:

int (*preparse)(struct key_preparsed_payload *prep);
void (*free_preparse)(struct key_preparsed_payload *prep);

If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases). The second operation is called to clean up if the first
was called.

preparse() is given the opportunity to fill in the following structure:

struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
const void *data;
size_t datalen;
size_t quotalen;
};

Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.

The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.

The preparser may also propose a description for the key by attaching it as a
string to the description field. This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function. This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.

This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.

The instantiate() and update() operations are then modified to look like this:

int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
int (*update)(struct key *key, struct key_preparsed_payload *prep);

and the new payload data is passed in *prep, whether or not it was preparsed.

Signed-off-by: David Howells <dhowells@redhat.com>

keys: fix user_defined key sparse messages

Replace the rcu_assign_pointer() calls with rcu_assign_keypointer().

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

keys: add a "logon" key type

For CIFS, we want to be able to store NTLM credentials (aka username
and password) in the keyring. We do not, however want to allow users
to fetch those keys back out of the keyring since that would be a
security risk.

Unfortunately, due to the nuances of key permission bits, it's not
possible to do this. We need to grant search permissions so the kernel
can find these keys, but that also implies permissions to read the
payload.

Resolve this by adding a new key_type. This key type is essentially
the same as key_type_user, but does not define a .read op. This
prevents the payload from ever being visible from userspace. This
key type also vets the description to ensure that it's "qualified"
by checking to ensure that it has a ':' in it that is preceded by
other characters.

Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

KEYS: Fix a NULL pointer deref in the user-defined key type

Fix a NULL pointer deref in the user-defined key type whereby updating a
negative key into a fully instantiated key will cause an oops to occur
when the code attempts to free the non-existent old payload.

This results in an oops that looks something like the following:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffff81085fa1>] __call_rcu+0x11/0x13e
PGD 3391d067 PUD 3894a067 PMD 0
Oops: 0002 [#1] SMP
CPU 1
Pid: 4354, comm: keyctl Not tainted 3.1.0-fsdevel+ #1140 /DG965RY
RIP: 0010:[<ffffffff81085fa1>] [<ffffffff81085fa1>] __call_rcu+0x11/0x13e
RSP: 0018:ffff88003d591df8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000006e
RDX: ffffffff8161d0c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88003d591e18 R08: 0000000000000000 R09: ffffffff8152fa6c
R10: 0000000000000000 R11: 0000000000000300 R12: ffff88003b8f9538
R13: ffffffff8161d0c0 R14: ffff88003b8f9d50 R15: ffff88003c69f908
FS: 00007f97eb18c720(0000) GS:ffff88003bd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000003d47a000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process keyctl (pid: 4354, threadinfo ffff88003d590000, task ffff88003c78a040)
Stack:
ffff88003e0ffde0 ffff88003b8f9538 0000000000000001 ffff88003b8f9d50
ffff88003d591e28 ffffffff810860f0 ffff88003d591e68 ffffffff8117bfea
ffff88003d591e68 ffffffff00000000 ffff88003e0ffde1 ffff88003e0ffde0
Call Trace:
[<ffffffff810860f0>] call_rcu_sched+0x10/0x12
[<ffffffff8117bfea>] user_update+0x8d/0xa2
[<ffffffff8117723a>] key_create_or_update+0x236/0x270
[<ffffffff811789b1>] sys_add_key+0x123/0x17e
[<ffffffff813b84bb>] system_call_fastpath+0x16/0x1b

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Neil Horman <nhorman@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

security,rcu: convert call_rcu(user_update_rcu_disposal) to kfree_rcu()

The rcu callback user_update_rcu_disposal() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(user_update_rcu_disposal).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

KEYS: Improve /proc/keys

Improve /proc/keys by:

(1) Don't attempt to summarise the payload of a negated key. It won't have
one. To this end, a helper function - key_is_instantiated() has been
added that allows the caller to find out whether the key is positively
instantiated (as opposed to being uninstantiated or negatively
instantiated).

(2) Do show keys that are negative, expired or revoked rather than hiding
them. This requires an override flag (no_state_check) to be passed to
search_my_process_keyrings() and keyring_search_aux() to suppress this
check.

Without this, keys that are possessed by the caller, but only grant
permissions to the caller if possessed are skipped as the possession check
fails.

Keys that are visible due to user, group or other checks are visible with
or without this patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

KEYS: Add an RCU payload dereference macro

Add an RCU payload dereference macro as this seems to be a common piece of code
amongst key types that use RCU referenced payloads.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

KEYS: Do some style cleanup in the key management code.

Do a bit of a style clean up in the key management code. No functional
changes.

Done using:

perl -p -i -e 's!^/[*]*/\n!!' security/keys/*.c
perl -p -i -e 's!} /[*] end [a-z0-9_]*[(][)] [*]/\n!}\n!' security/keys/*.c
sed -i -s -e ": next" -e N -e 's/^\n[}]$/}/' -e t -e P -e 's/^.*\n//' -e "b next" security/keys/*.c

To remove /*****/ lines, remove comments on the closing brace of a
function to name the function and remove blank lines before the closing
brace of a function.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KEYS: Fix an RCU warning in the reading of user keys

Fix an RCU warning in the reading of user keys:

===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/user_defined.c:202 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by keyctl/3637:
#0: (&key->sem){+++++.}, at: [<ffffffff811a80ae>] keyctl_read_key+0x9c/0xcf

stack backtrace:
Pid: 3637, comm: keyctl Not tainted 2.6.34-rc5-cachefs #18
Call Trace:
[<ffffffff81051f6c>] lockdep_rcu_dereference+0xaa/0xb2
[<ffffffff811aa55f>] user_read+0x47/0x91
[<ffffffff811a80be>] keyctl_read_key+0xac/0xcf
[<ffffffff811a8a06>] sys_keyctl+0x75/0xb7
[<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

KEYS: Fix an RCU warning in the reading of user keys

Fix an RCU warning in the reading of user keys:

===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/user_defined.c:202 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by keyctl/3637:
#0: (&key->sem){+++++.}, at: [<ffffffff811a80ae>] keyctl_read_key+0x9c/0xcf

stack backtrace:
Pid: 3637, comm: keyctl Not tainted 2.6.34-rc5-cachefs #18
Call Trace:
[<ffffffff81051f6c>] lockdep_rcu_dereference+0xaa/0xb2
[<ffffffff811aa55f>] user_read+0x47/0x91
[<ffffffff811a80be>] keyctl_read_key+0xac/0xcf
[<ffffffff811a8a06>] sys_keyctl+0x75/0xb7
[<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

[PATCH] remove many unneeded #includes of sched.h

After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there. Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm. I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] keys: discard the contents of a key on revocation

Cause the keys linked to a keyring to be unlinked from it when revoked and it
causes the data attached to a user-defined key to be discarded when revoked.

This frees up most of the quota a key occupied at that point, rather than
waiting for the key to actually be destroyed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Keys: Remove key duplication

Remove the key duplication stuff since there's nothing that uses it, no way
to get at it and it's awkward to deal with for LSM purposes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Keys: Export user-defined keyring operations

Export user-defined key operations so that those who wish to define their
own key type based on the user-defined key operations may do so (as has
been requested).

The header file created has been placed into include/keys/user-type.h, thus
creating a directory where other key types may also be placed. Any
objections to doing this?

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-Off-By: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] eCryptfs: export user key type

Export this symbol to GPL modules for eCryptfs: an out-of-tree GPL'ed
filesystem.

Signed off by: Michael Halcrow <mhalcrow@us.ibm.com>

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

[PATCH] keys: Discard key spinlock and use RCU for key payload

The attached patch changes the key implementation in a number of ways:

(1) It removes the spinlock from the key structure.

(2) The key flags are now accessed using atomic bitops instead of
write-locking the key spinlock and using C bitwise operators.

The three instantiation flags are dealt with with the construction
semaphore held during the request_key/instantiate/negate sequence, thus
rendering the spinlock superfluous.

The key flags are also now bit numbers not bit masks.

(3) The key payload is now accessed using RCU. This permits the recursive
keyring search algorithm to be simplified greatly since no locks need be
taken other than the usual RCU preemption disablement. Searching now does
not require any locks or semaphores to be held; merely that the starting
keyring be pinned.

(4) The keyring payload now includes an RCU head so that it can be disposed
of by call_rcu(). This requires that the payload be copied on unlink to
prevent introducing races in copy-down vs search-up.

(5) The user key payload is now a structure with the data following it. It
includes an RCU head like the keyring payload and for the same reason. It
also contains a data length because the data length in the key may be
changed on another CPU whilst an RCU protected read is in progress on the
payload. This would then see the supposed RCU payload and the on-key data
length getting out of sync.

I'm tempted to drop the key's datalen entirely, except that it's used in
conjunction with quota management and so is a little tricky to get rid
of.

(6) Update the keys documentation.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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!