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| author | Ryan Lee <ryan.lee@canonical.com> | 2025-05-01 12:54:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-28 16:22:35 +0200 |
| commit | eda378a0abdf8d7e25a6a542f6f00dd281501613 (patch) | |
| tree | 813e0491752fed3448d511d8e35403f0c958740b /security | |
| parent | 77d2993d8b3d8562e1505b5066dedc8cb00fa1ae (diff) | |
| download | linux-eda378a0abdf8d7e25a6a542f6f00dd281501613.tar.gz linux-eda378a0abdf8d7e25a6a542f6f00dd281501613.tar.bz2 linux-eda378a0abdf8d7e25a6a542f6f00dd281501613.zip | |
apparmor: ensure WB_HISTORY_SIZE value is a power of 2
[ Upstream commit 6c055e62560b958354625604293652753d82bcae ]
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 <ryan.lee@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/apparmor/include/match.h | 3 | ||||
| -rw-r--r-- | security/apparmor/match.c | 1 |
2 files changed, 3 insertions, 1 deletions
diff --git a/security/apparmor/include/match.h b/security/apparmor/include/match.h index 884489590588..29306ec87fd1 100644 --- a/security/apparmor/include/match.h +++ b/security/apparmor/include/match.h @@ -141,7 +141,8 @@ unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start, void aa_dfa_free_kref(struct kref *kref); -#define WB_HISTORY_SIZE 24 +/* This needs to be a power of 2 */ +#define WB_HISTORY_SIZE 32 struct match_workbuf { unsigned int count; unsigned int pos; diff --git a/security/apparmor/match.c b/security/apparmor/match.c index 3e9e1eaf990e..0e683ee323e3 100644 --- a/security/apparmor/match.c +++ b/security/apparmor/match.c @@ -672,6 +672,7 @@ unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start, #define inc_wb_pos(wb) \ do { \ + BUILD_BUG_ON_NOT_POWER_OF_2(WB_HISTORY_SIZE); \ wb->pos = (wb->pos + 1) & (WB_HISTORY_SIZE - 1); \ wb->len = (wb->len + 1) & (WB_HISTORY_SIZE - 1); \ } while (0) |