audit: move calcs after alloc and check when logging set loginuid

Move the calculations of values after the allocation in case the
allocation fails.  This avoids wasting effort in the rare case that it
fails, but more importantly saves us extra logic to release the tty
ref.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 71e14d836e69..33dafa70229d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1985,14 +1985,15 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
         if (!audit_enabled)
                 return;
 
+        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
+        if (!ab)
+                return;
+
         uid = from_kuid(&init_user_ns, task_uid(current));
         oldloginuid = from_kuid(&init_user_ns, koldloginuid);
         loginuid = from_kuid(&init_user_ns, kloginuid),
         tty = audit_get_tty(current);
 
-        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
-        if (!ab)
-                return;
         audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
         audit_log_task_context(ab);
         audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",