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>
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>
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>
- increase left match history buffer size to provide inproved conflict
resolution in overlapping execution rules.
- switch buffer allocation to use a memory pool and GFP_KERNEL
where possible.
- add compression of policy blobs to reduce memory usage.
+ Cleanups
- fix spelling mistake "immutible" -> "immutable"
+ Bug fixes
- fix unsigned len comparison in update_for_len macro
- fix sparse warning for type-casting of current->real_cred
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Merge tag 'apparmor-pr-2019-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor
Pull apparmor updates from John Johansen:
"Features:
- increase left match history buffer size to provide improved
conflict resolution in overlapping execution rules.
- switch buffer allocation to use a memory pool and GFP_KERNEL where
possible.
- add compression of policy blobs to reduce memory usage.
Cleanups:
- fix spelling mistake "immutible" -> "immutable"
Bug fixes:
- fix unsigned len comparison in update_for_len macro
- fix sparse warning for type-casting of current->real_cred"
* tag 'apparmor-pr-2019-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
apparmor: make it so work buffers can be allocated from atomic context
apparmor: reduce rcu_read_lock scope for aa_file_perm mediation
apparmor: fix wrong buffer allocation in aa_new_mount
apparmor: fix unsigned len comparison with less than zero
apparmor: increase left match history buffer size
apparmor: Switch to GFP_KERNEL where possible
apparmor: Use a memory pool instead per-CPU caches
apparmor: Force type-casting of current->real_cred
apparmor: fix spelling mistake "immutible" -> "immutable"
apparmor: fix blob compression when ns is forced on a policy load
apparmor: fix missing ZLIB defines
apparmor: fix blob compression build failure on ppc
apparmor: Initial implementation of raw policy blob compression
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>
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>
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>
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>
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>
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>
The dfa is currently setup to be shared (has the basis of refcounting)
but currently can't be because the count can't be increased.
Signed-off-by: John Johansen <john.johansen@canonical.com>
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>
Remove kobject.h from files which don't need it, notably,
sched.h and fs.h.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
