upstream: a little debug() in the security key interface

OpenBSD-Commit-ID: 4c70300609a5c8b19707207bb7ad4109e963b0e8
diff --git a/ssh-sk.c b/ssh-sk.c
index 591c643..63f1d1d 100644
--- a/ssh-sk.c
+++ b/ssh-sk.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk.c,v 1.12 2019/11/14 21:27:30 djm Exp $ */
+/* $OpenBSD: ssh-sk.c,v 1.13 2019/11/16 22:42:30 djm Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -264,6 +264,10 @@
 	int r = SSH_ERR_INTERNAL_ERROR;
 	int alg;
 
+	debug("%s: provider \"%s\", application \"%s\", flags 0x%02x, "
+	    "challenge len %zu", __func__, provider_path, application,
+	    flags, challenge_buf == NULL ? 0 : sshbuf_len(challenge_buf));
+
 	*keyp = NULL;
 	if (attest)
 		sshbuf_reset(attest);
@@ -461,6 +465,9 @@
 	struct sshbuf *inner_sig = NULL, *sig = NULL;
 	uint8_t message[32];
 
+	debug("%s: provider \"%s\", key \"%s\", flags 0x%02x", __func__,
+	    provider_path, sshkey_type(key), key->sk_flags);
+
 	if (sigp != NULL)
 		*sigp = NULL;
 	if (lenp != NULL)