kernel/linux.git/security/apparmor/include/match.h, branch v6.18.21

apparmor: fix differential encoding verification

2026-03-13T16:23:29+00:00

commit 39440b137546a3aa383cfdabc605fb73811b6093 upstream. Differential encoding allows loops to be created if it is abused. To prevent this the unpack should verify that a diff-encode chain terminates. Unfortunately the differential encode verification had two bugs. 1. it conflated states that had gone through check and already been marked, with states that were currently being checked and marked. This means that loops in the current chain being verified are treated as a chain that has already been verified. 2. the order bailout on already checked states compared current chain check iterators j,k instead of using the outer loop iterator i. Meaning a step backwards in states in the current chain verification was being mistaken for moving to an already verified state. Move to a double mark scheme where already verified states get a different mark, than the current chain being kept. This enables us to also drop the backwards verification check that was the cause of the second error as any already verified state is already marked. Fixes: 031dcc8f4e84 ("apparmor: dfa add support for state differential encoding") Reported-by: Qualys Security Advisory Tested-by: Salvatore Bonaccorso Reviewed-by: Georgia Garcia Reviewed-by: Cengiz Can Signed-off-by: John Johansen Signed-off-by: Greg Kroah-Hartman

apparmor: Fix & Optimize table creation from possibly unaligned memory

2026-02-26T22:59:41+00:00

[ Upstream commit 6fc367bfd4c8886e6b1742aabbd1c0bdc310db3a ] Source blob may come from userspace and might be unaligned. Try to optize the copying process by avoiding unaligned memory accesses. - Added Fixes tag - Added "Fix &" to description as this doesn't just optimize but fixes a potential unaligned memory access Fixes: e6e8bf418850d ("apparmor: fix restricted endian type warnings for dfa unpack") Signed-off-by: Helge Deller [jj: remove duplicate word "convert" in comment trigger checkpatch warning] Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: fix loop detection used in conflicting attachment resolution

2025-05-26T03:14:53+00:00

Conflicting attachment resolution is based on the number of states traversed to reach an accepting state in the attachment DFA, accounting for DFA loops traversed during the matching process. However, the loop counting logic had multiple bugs: - The inc_wb_pos macro increments both position and length, but length is supposed to saturate upon hitting buffer capacity, instead of wrapping around. - If no revisited state is found when traversing the history, is_loop would still return true, as if there was a loop found the length of the history buffer, instead of returning false and signalling that no loop was found. As a result, the adjustment step of aa_dfa_leftmatch would sometimes produce negative counts with loop- free DFAs that traversed enough states. - The iteration in the is_loop for loop is supposed to stop before i = wb->len, so the conditional should be < instead of <=. This patch fixes the above bugs as well as the following nits: - The count and size fields in struct match_workbuf were not used, so they can be removed. - The history buffer in match_workbuf semantically stores aa_state_t and not unsigned ints, even if aa_state_t is currently unsigned int. - The local variables in is_loop are counters, and thus should be unsigned ints instead of aa_state_t's. Fixes: 21f606610502 ("apparmor: improve overlapping domain attachment resolution") Signed-off-by: Ryan Lee Co-developed-by: John Johansen Signed-off-by: John Johansen

apparmor: ensure WB_HISTORY_SIZE value is a power of 2

2025-05-18T01:20:10+00:00

WB_HISTORY_SIZE was defined to be a value not a power of 2, despite a comment in the declaration of struct match_workbuf stating it is and a modular arithmetic usage in the inc_wb_pos macro assuming that it is. Bump WB_HISTORY_SIZE's value up to 32 and add a BUILD_BUG_ON_NOT_POWER_OF_2 line to ensure that any future changes to the value of WB_HISTORY_SIZE respect this requirement. Fixes: 136db994852a ("apparmor: increase left match history buffer size") Signed-off-by: Ryan Lee Signed-off-by: John Johansen

apparmor: fix some kernel-doc issues in header files

2025-05-17T08:52:25+00:00

Fix kernel-doc warnings in apparmor header files as reported by scripts/kernel-doc: cred.h:128: warning: expecting prototype for end_label_crit_section(). Prototype was for end_current_label_crit_section() instead file.h:108: warning: expecting prototype for aa_map_file_perms(). Prototype was for aa_map_file_to_perms() instead lib.h:159: warning: Function parameter or struct member 'hname' not described in 'basename' lib.h:159: warning: Excess function parameter 'name' description in 'basename' match.h:21: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst * The format used for transition tables is based on the GNU flex table perms.h:109: warning: Function parameter or struct member 'accum' not described in 'aa_perms_accum_raw' perms.h:109: warning: Function parameter or struct member 'addend' not described in 'aa_perms_accum_raw' perms.h:136: warning: Function parameter or struct member 'accum' not described in 'aa_perms_accum' perms.h:136: warning: Function parameter or struct member 'addend' not described in 'aa_perms_accum' Signed-off-by: Randy Dunlap Reviewed-by: Ryan Lee Cc: John Johansen Cc: John Johansen Cc: apparmor@lists.ubuntu.com Cc: linux-security-module@vger.kernel.org Cc: Paul Moore Cc: James Morris Cc: "Serge E. Hallyn" Signed-off-by: John Johansen

apparmor: add support for 2^24 states to the dfa state machine.

2024-11-27T03:21:05+00:00

Currently the dfa state machine is limited by its default, next, and check tables using u16. Allow loading of u32 tables, and if u16 tables are loaded map them to u32. The number of states allowed does not increase to 2^32 because the base table uses the top 8 bits of its u32 for flags. Moving the flags into a separate table allowing a full 2^32 bit range wil be done in a separate patch. Link: https://gitlab.com/apparmor/apparmor/-/issues/419 Signed-off-by: John Johansen

apparmor: refcount the pdb

2023-10-18T22:30:47+00:00

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 Signed-off-by: John Johansen

apparmor: preparse for state being more than just an integer

2022-10-03T21:49:03+00:00

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

apparmor: add outofband transition and use it in xattr match

2020-01-21T14:00:20+00:00

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

apparmor: add a valid state flags check

2020-01-18T23:37:24+00:00

Add a check to ensure only known state flags are set on each state in the dfa. Signed-off-by: John Johansen