From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> [ Upstream commit 5797e861e402fff2bedce4ec8b7c89f4248b6073 ] syzbot is reporting that tomoyo's quota check is racy [1]. But this check is tolerant of some degree of inaccuracy. Thus, teach KCSAN to ignore this data race. [1] https://syzkaller.appspot.com/bug?id=999533deec7ba6337f8aa25d8bd1a4d5f7e50476 Reported-by: syzbot <syzbot+0789a72b46fd91431bd8@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- security/tomoyo/file.c | 16 ++++++++-------- security/tomoyo/network.c | 8 ++++---- security/tomoyo/util.c | 24 ++++++++++++------------ 3 files changed, 24 insertions(+), 24 deletions(-) diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c index 051f7297877cb..1e6077568fdec 100644 --- a/security/tomoyo/file.c +++ b/security/tomoyo/file.c @@ -362,14 +362,14 @@ static bool tomoyo_merge_path_acl(struct tomoyo_acl_info *a, { u16 * const a_perm = &container_of(a, struct tomoyo_path_acl, head) ->perm; - u16 perm = *a_perm; + u16 perm = READ_ONCE(*a_perm); const u16 b_perm = container_of(b, struct tomoyo_path_acl, head)->perm; if (is_delete) perm &= ~b_perm; else perm |= b_perm; - *a_perm = perm; + WRITE_ONCE(*a_perm, perm); return !perm; } @@ -437,7 +437,7 @@ static bool tomoyo_merge_mkdev_acl(struct tomoyo_acl_info *a, { u8 *const a_perm = &container_of(a, struct tomoyo_mkdev_acl, head)->perm; - u8 perm = *a_perm; + u8 perm = READ_ONCE(*a_perm); const u8 b_perm = container_of(b, struct tomoyo_mkdev_acl, head) ->perm; @@ -445,7 +445,7 @@ static bool tomoyo_merge_mkdev_acl(struct tomoyo_acl_info *a, perm &= ~b_perm; else perm |= b_perm; - *a_perm = perm; + WRITE_ONCE(*a_perm, perm); return !perm; } @@ -517,14 +517,14 @@ static bool tomoyo_merge_path2_acl(struct tomoyo_acl_info *a, { u8 * const a_perm = &container_of(a, struct tomoyo_path2_acl, head) ->perm; - u8 perm = *a_perm; + u8 perm = READ_ONCE(*a_perm); const u8 b_perm = container_of(b, struct tomoyo_path2_acl, head)->perm; if (is_delete) perm &= ~b_perm; else perm |= b_perm; - *a_perm = perm; + WRITE_ONCE(*a_perm, perm); return !perm; } @@ -655,7 +655,7 @@ static bool tomoyo_merge_path_number_acl(struct tomoyo_acl_info *a, { u8 * const a_perm = &container_of(a, struct tomoyo_path_number_acl, head)->perm; - u8 perm = *a_perm; + u8 perm = READ_ONCE(*a_perm); const u8 b_perm = container_of(b, struct tomoyo_path_number_acl, head) ->perm; @@ -663,7 +663,7 @@ static bool tomoyo_merge_path_number_acl(struct tomoyo_acl_info *a, perm &= ~b_perm; else perm |= b_perm; - *a_perm = perm; + WRITE_ONCE(*a_perm, perm); return !perm; } diff --git a/security/tomoyo/network.c b/security/tomoyo/network.c index f9ff121d7e1eb..a89ed55d85d41 100644 --- a/security/tomoyo/network.c +++ b/security/tomoyo/network.c @@ -233,14 +233,14 @@ static bool tomoyo_merge_inet_acl(struct tomoyo_acl_info *a, { u8 * const a_perm = &container_of(a, struct tomoyo_inet_acl, head)->perm; - u8 perm = *a_perm; + u8 perm = READ_ONCE(*a_perm); const u8 b_perm = container_of(b, struct tomoyo_inet_acl, head)->perm; if (is_delete) perm &= ~b_perm; else perm |= b_perm; - *a_perm = perm; + WRITE_ONCE(*a_perm, perm); return !perm; } @@ -259,14 +259,14 @@ static bool tomoyo_merge_unix_acl(struct tomoyo_acl_info *a, { u8 * const a_perm = &container_of(a, struct tomoyo_unix_acl, head)->perm; - u8 perm = *a_perm; + u8 perm = READ_ONCE(*a_perm); const u8 b_perm = container_of(b, struct tomoyo_unix_acl, head)->perm; if (is_delete) perm &= ~b_perm; else perm |= b_perm; - *a_perm = perm; + WRITE_ONCE(*a_perm, perm); return !perm; } diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c index 176b803ebcfc9..e89cac913583c 100644 --- a/security/tomoyo/util.c +++ b/security/tomoyo/util.c @@ -1058,30 +1058,30 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r) if (ptr->is_deleted) continue; + /* + * Reading perm bitmap might race with tomoyo_merge_*() because + * caller does not hold tomoyo_policy_lock mutex. But exceeding + * max_learning_entry parameter by a few entries does not harm. + */ switch (ptr->type) { case TOMOYO_TYPE_PATH_ACL: - perm = container_of(ptr, struct tomoyo_path_acl, head) - ->perm; + data_race(perm = container_of(ptr, struct tomoyo_path_acl, head)->perm); break; case TOMOYO_TYPE_PATH2_ACL: - perm = container_of(ptr, struct tomoyo_path2_acl, head) - ->perm; + data_race(perm = container_of(ptr, struct tomoyo_path2_acl, head)->perm); break; case TOMOYO_TYPE_PATH_NUMBER_ACL: - perm = container_of(ptr, struct tomoyo_path_number_acl, - head)->perm; + data_race(perm = container_of(ptr, struct tomoyo_path_number_acl, head) + ->perm); break; case TOMOYO_TYPE_MKDEV_ACL: - perm = container_of(ptr, struct tomoyo_mkdev_acl, - head)->perm; + data_race(perm = container_of(ptr, struct tomoyo_mkdev_acl, head)->perm); break; case TOMOYO_TYPE_INET_ACL: - perm = container_of(ptr, struct tomoyo_inet_acl, - head)->perm; + data_race(perm = container_of(ptr, struct tomoyo_inet_acl, head)->perm); break; case TOMOYO_TYPE_UNIX_ACL: - perm = container_of(ptr, struct tomoyo_unix_acl, - head)->perm; + data_race(perm = container_of(ptr, struct tomoyo_unix_acl, head)->perm); break; case TOMOYO_TYPE_MANUAL_TASK_ACL: perm = 0; -- 2.27.0
