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tomoyo: ignore data race while checking quota 

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@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
This commit is contained in:
Tetsuo Handa 2021-02-01 11:52:11 +09:00
parent 1048ba83fb
commit 5797e861e4
3 changed files with 24 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
security/tomoyo/file.c
View File

@ -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;
}

8
security/tomoyo/network.c
View File

@ -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;
}

24
security/tomoyo/util.c
View File

@ -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;