diff options
| author | Ryan Lee <ryan.lee@canonical.com> | 2025-05-01 12:54:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-15 16:39:15 +0200 |
| commit | d79ddfb8258aad0b5b719b6dcbf4407a905188fe (patch) | |
| tree | 2012771e21d5879dcc8b6f46afbead6b62e70e73 | |
| parent | cb6657bde2a5a34bc05461e680a1ee19e82b0353 (diff) | |
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>
| -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 536ce3abd598..b45fc39fa837 100644 --- a/security/apparmor/include/match.h +++ b/security/apparmor/include/match.h @@ -137,7 +137,8 @@ aa_state_t aa_dfa_matchn_until(struct aa_dfa *dfa, aa_state_t 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 f2d9c57f8794..1ceabde550f2 100644 --- a/security/apparmor/match.c +++ b/security/apparmor/match.c @@ -681,6 +681,7 @@ aa_state_t aa_dfa_matchn_until(struct aa_dfa *dfa, aa_state_t 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) |