From: Casey Schaufler casey@schaufler-ca.com
[ 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@kernel.dk Acked-by: Jens Axboe axboe@kernel.dk Acked-by: Eric W. Biederman ebiederm@xmission.com Signed-off-by: Casey Schaufler casey@schaufler-ca.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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());