lockdown: Print current->comm in restriction messages

Print the content of current->comm in messages generated by lockdown to
indicate a restriction that was hit.  This makes it a bit easier to find
out what caused the message.

The message now patterned something like:

        Lockdown: <comm>: <what> is restricted; see man kernel_lockdown.7

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 84df03b..0068cec 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -81,10 +81,14 @@ early_param("lockdown", lockdown_param);
  */
 static int lockdown_is_locked_down(enum lockdown_reason what)
 {
+	if (WARN(what >= LOCKDOWN_CONFIDENTIALITY_MAX,
+		 "Invalid lockdown reason"))
+		return -EPERM;
+
 	if (kernel_locked_down >= what) {
 		if (lockdown_reasons[what])
-			pr_notice("Lockdown: %s is restricted; see man kernel_lockdown.7\n",
-				  lockdown_reasons[what]);
+			pr_notice("Lockdown: %s: %s is restricted; see man kernel_lockdown.7\n",
+				  current->comm, lockdown_reasons[what]);
 		return -EPERM;
 	}