5.10-stable review patch. If anyone has any objections, please let me know.
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From: Ryan Lee ryan.lee@canonical.com
[ 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 --- security/apparmor/include/match.h | 3 ++- security/apparmor/match.c | 1 + 2 files changed, 3 insertions(+), 1 deletion(-)
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)