fs: handle failed audit_log_start properly
audit_log_start() may return NULL, this is unchecked by the caller in
audit_log_link_denied() and could cause a NULL ptr deref.
Introduced by commit a51d9eaa ("fs: add link restriction audit reporting").
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/audit.c b/kernel/audit.c
index 4d0ceed..40414e9 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1440,6 +1440,8 @@
ab = audit_log_start(current->audit_context, GFP_KERNEL,
AUDIT_ANOM_LINK);
+ if (!ab)
+ return;
audit_log_format(ab, "op=%s action=denied", operation);
audit_log_format(ab, " pid=%d comm=", current->pid);
audit_log_untrustedstring(ab, current->comm);