net: Check the correct namespace when spoofing pid over SCM_RIGHTS

commit d661684cf6820331feae71146c35da83d794467e upstream.

This is a security bug.

The follow-up will fix nsproxy to discourage this type of issue from
happening again.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/scm.c b/net/core/scm.c
index 03795d0..b4da80b 100644 (file)
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -54,7 +54,7 @@ static __inline__ int scm_check_creds(struct ucred *creds)
                return -EINVAL;
 
        if ((creds->pid == task_tgid_vnr(current) ||
-            ns_capable(current->nsproxy->pid_ns->user_ns, CAP_SYS_ADMIN)) &&
+            ns_capable(task_active_pid_ns(current)->user_ns, CAP_SYS_ADMIN)) &&
            ((uid_eq(uid, cred->uid)   || uid_eq(uid, cred->euid) ||
              uid_eq(uid, cred->suid)) || nsown_capable(CAP_SETUID)) &&
            ((gid_eq(gid, cred->gid)   || gid_eq(gid, cred->egid) ||