apparmor: refcount the pdb

With the move to permission tables the dfa is no longer a stand
alone entity when used, needing a minimum of a permission table.
However it still could be shared among different pdbs each using
a different permission table.

Instead of duping the permission table when sharing a pdb, add a
refcount to the pdb so it can be easily shared.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: Fix kernel-doc warnings in apparmor/match.c

Fix kernel-doc warnings:

security/apparmor/match.c:148: warning: Function parameter or member
'tables' not described in 'verify_table_headers'
security/apparmor/match.c:289: warning: Excess function parameter
'kr' description in 'aa_dfa_free_kref'
security/apparmor/match.c:289: warning: Function parameter or member
'kref' not described in 'aa_dfa_free_kref'

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: Add __init annotation to aa_{setup/teardown}_dfa_engine()

The aa_setup_dfa_engine() and aa_teardown_dfa_engine() is only called in
apparmor_init(), so let us add __init annotation to them.

Fixes: 11c236b89d7c ("apparmor: add a default null dfa")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: preparse for state being more than just an integer

Convert from an unsigned int to a state_t for state position. This is
a step in prepping for the state position carrying some additional
flags, and a limited form of backtracking to support variables.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: ensure that dfa state tables have entries

Currently it is possible to specify a state machine table with 0 length,
this is not valid as optional tables are specified by not defining
the table as present. Further this allows by-passing the base tables
range check against the next/check tables.

Fixes: d901d6a298dc ("apparmor: dfa split verification of table headers")
Reported-by: Mike Salvatore <mike.salvatore@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: add outofband transition and use it in xattr match

There are cases where the a special out of band transition that can
not be triggered by input is useful in separating match conditions
in the dfa encoding.

The null_transition is currently used as an out of band transition
for match conditions that can not contain a \0 in their input
but apparmor needs an out of band transition for cases where
the match condition is allowed to contain any input character.

Achieve this by allowing for an explicit transition out of input
range that can only be triggered by code.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: add consistency check between state and dfa diff encode flags

Check that a states diff encode flag is only set if diff encode is
enabled in the dfa header.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: add a valid state flags check

Add a check to ensure only known state flags are set on each
state in the dfa.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: increase left match history buffer size

There have been cases reported where a history buffer size of 8 was
not enough to resolve conflict overlaps. Increase the buffer to and
get rid of the size element which is currently just storing the
constant WB_HISTORY_SIZE.

Signed-off-by: John Johansen <john.johansen@canonical.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

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 version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

apparmor: fix typo "traverse"

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Acked-by: Christian Boltz <apparmor@cboltz.de>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: Fix an error code in verify_table_headers()

We accidentally return a positive EPROTO instead of a negative -EPROTO.
Since 71 is not an error pointer, that means it eventually results in an
Oops in the caller.

Fixes: d901d6a298dc ("apparmor: dfa split verification of table headers")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: improve overlapping domain attachment resolution

Overlapping domain attachments using the current longest left exact
match fail in some simple cases, and with the fix to ensure consistent
behavior by failing unresolvable attachments it becomes important to
do a better job.

eg. under the current match the following are unresolvable where
the alternation is clearly a better match under the most specific
left match rule.
/**
/{bin/,}usr/

Use a counting match that detects when a loop in the state machine is
enter, and return the match count to provide a better specific left
match resolution.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: dfa split verification of table headers

separate the different types of verification so they are logically
separate and can be reused separate of each other.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: dfa add support for state differential encoding

State differential encoding can provide better compression for
apparmor policy, without having significant impact on match time.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: dfa move character match into a macro

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: use the dfa to do label parse string splitting

The current split scheme is actually wrong in that it splits
///&

where that is invalid and should fail. Use the dfa to do a proper
bounded split without having to worry about getting the string
processing right in code.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>

apparmor: add first substr match to dfa

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>

doc: ReSTify apparmor.txt

Adjusts for ReST markup and moves under LSM admin guide.

Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

mm: introduce kv[mz]alloc helpers

Patch series "kvmalloc", v5.

There are many open coded kmalloc with vmalloc fallback instances in the
tree. Most of them are not careful enough or simply do not care about
the underlying semantic of the kmalloc/page allocator which means that
a) some vmalloc fallbacks are basically unreachable because the kmalloc
part will keep retrying until it succeeds b) the page allocator can
invoke a really disruptive steps like the OOM killer to move forward
which doesn't sound appropriate when we consider that the vmalloc
fallback is available.

As it can be seen implementing kvmalloc requires quite an intimate
knowledge if the page allocator and the memory reclaim internals which
strongly suggests that a helper should be implemented in the memory
subsystem proper.

Most callers, I could find, have been converted to use the helper
instead. This is patch 6. There are some more relying on __GFP_REPEAT
in the networking stack which I have converted as well and Eric Dumazet
was not opposed [2] to convert them as well.

[1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org
[2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com

This patch (of 9):

Using kmalloc with the vmalloc fallback for larger allocations is a
common pattern in the kernel code. Yet we do not have any common helper
for that and so users have invented their own helpers. Some of them are
really creative when doing so. Let's just add kv[mz]alloc and make sure
it is implemented properly. This implementation makes sure to not make
a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also
to not warn about allocation failures. This also rules out the OOM
killer as the vmalloc is a more approapriate fallback than a disruptive
user visible action.

This patch also changes some existing users and removes helpers which
are specific for them. In some cases this is not possible (e.g.
ext4_kvmalloc, libcfs_kvzalloc) because those seems to be broken and
require GFP_NO{FS,IO} context which is not vmalloc compatible in general
(note that the page table allocation is GFP_KERNEL). Those need to be
fixed separately.

While we are at it, document that __vmalloc{_node} about unsupported gfp
mask because there seems to be a lot of confusion out there.
kvmalloc_node will warn about GFP_KERNEL incompatible (which are not
superset) flags to catch new abusers. Existing ones would have to die
slowly.

[sfr@canb.auug.org.au: f2fs fixup]
Link: http://lkml.kernel.org/r/20170320163735.332e64b7@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170306103032.2540-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andreas Dilger <adilger@dilger.ca> [ext4 part]
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

apparmor: fix restricted endian type warnings for dfa unpack

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: add a default null dfa

Instead of testing whether a given dfa exists in every code path, have
a default null dfa that is used when loaded policy doesn't provide a
dfa.

This will let us get rid of special casing and avoid dereference bugs
when special casing is missed.

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: move lib definitions into separate lib include

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: do not expose kernel stack

Do not copy uninitalized fields th.td_hilen, th.td_data.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: don't check for vmalloc_addr if kvzalloc() failed

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: add missing id bounds check on dfa verification

Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: reserve and mask off the top 8 bits of the base field

The top 8 bits of the base field have never been used, in fact can't
be used, by the current 'dfa16' format. However they will be used in the
future as flags, so mask them off when using base as an index value.

Note: the use of the top 8 bits, without masking is trapped by the verify
checks that base entries are within the size bounds.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>

apparmor: misc cleanup of match

tidying up comments, includes and defines

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>

apparmor: add kvzalloc to handle zeroing for kvmalloc

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Steve Beattie <sbeattie@ubuntu.com>

AppArmor: Update dfa matching routines.

Update aa_dfa_match so that it doesn't result in an input string being
walked twice (once to get its length and another time to match)

Add a single step functions
aa_dfa_next

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>

Create Documentation/security/,
move LSM-, credentials-, and keys-related files from Documentation/
to Documentation/security/,
add Documentation/security/00-INDEX, and
update all occurrences of Documentation/<moved_file>
to Documentation/security/<moved_file>.

Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

AppArmor: dfa match engine

A basic dfa matching engine based off the dfa engine in the Dragon
Book. It uses simple row comb compression with a check field.

This allows AppArmor to do pattern matching in linear time, and also
avoids stack issues that an nfa based engine may have. The dfa
engine uses a byte based comparison, with all values being valid.
Any potential character encoding are handled user side when the dfa
tables are created. By convention AppArmor uses \0 to separate two
dependent path matches since \0 is not a valid path character
(this is done in the link permission check).

The dfa tables are generated in user space and are verified at load
time to be internally consistent.

There are several future improvements planned for the dfa engine:
* The dfa engine may be converted to a hybrid nfa-dfa engine, with
a fixed size limited stack. This would allow for size time
tradeoffs, by inserting limited nfa states to help control
state explosion that can occur with dfas.
* The dfa engine may pickup the ability to do limited dynamic
variable matching, instead of fixing all variables at policy
load time.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>