From: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
[ Upstream commit 942cb357ae7d9249088e3687ee6a00ed2745a0c7 ]
Smack assumes that kernel threads are privileged for smackfs
operations. This was necessary because the credential of the
kernel thread was not related to a user operation. With io_uring
the credential does reflect a user's rights and can be used.
Suggested-by: Jens Axboe <axboe@xxxxxxxxx>
Acked-by: Jens Axboe <axboe@xxxxxxxxx>
Acked-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
security/smack/smack_access.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index efe2406a39609..7eabb448acab4 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -688,9 +688,10 @@ bool smack_privileged_cred(int cap, const struct cred *cred)
bool smack_privileged(int cap)
{
/*
- * All kernel tasks are privileged
+ * Kernel threads may not have credentials we can use.
+ * The io_uring kernel threads do have reliable credentials.
*/
- if (unlikely(current->flags & PF_KTHREAD))
+ if ((current->flags & (PF_KTHREAD | PF_IO_WORKER)) == PF_KTHREAD)
return true;
return smack_privileged_cred(cap, current_cred());
--
2.27.0
