3 files changed, 12 insertions, 5 deletions

diff --git a/auth2-pubkey.c b/auth2-pubkey.c
index eac79cc3d..0713a9de8 100644
--- a/auth2-pubkey.c
+++ b/auth2-pubkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-pubkey.c,v 1.73 2017/12/19 00:24:34 djm Exp $ */
+/* $OpenBSD: auth2-pubkey.c,v 1.74 2017/12/21 00:00:28 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -214,7 +214,7 @@ userauth_pubkey(struct ssh *ssh)
                 authenticated = 0;
                 if (PRIVSEP(user_key_allowed(authctxt->pw, key, 1)) &&
                     PRIVSEP(sshkey_verify(key, sig, slen, sshbuf_ptr(b),
-                    sshbuf_len(b), pkalg, ssh->compat)) == 0) {
+                    sshbuf_len(b), NULL, ssh->compat)) == 0) {
                         authenticated = 1;
                 }
                 sshbuf_free(b);
diff --git a/monitor.c b/monitor.c
index 5b8f0ef65..b0227eee1 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor.c,v 1.176 2017/12/18 02:25:15 djm Exp $ */
+/* $OpenBSD: monitor.c,v 1.177 2017/12/21 00:00:28 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -1353,6 +1353,12 @@ mm_answer_keyverify(int sock, struct sshbuf *m)
           !monitor_allowed_key(blob, bloblen))
                 fatal("%s: bad key, not previously allowed", __func__);
 
+        /* Empty signature algorithm means NULL. */
+        if (*sigalg == '\0') {
+                free(sigalg);
+                sigalg = NULL;
+        }
+
         /* XXX use sshkey_froms here; need to change key_blob, etc. */
         if ((r = sshkey_from_blob(blob, bloblen, &key)) != 0)
                 fatal("%s: bad public key blob: %s", __func__, ssh_err(r));
@@ -1383,6 +1389,7 @@ mm_answer_keyverify(int sock, struct sshbuf *m)
         free(blob);
         free(signature);
         free(data);
+        free(sigalg);
 
         monitor_reset_key_state();
 
diff --git a/monitor_wrap.c b/monitor_wrap.c
index 502d41687..7471e4546 100644
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor_wrap.c,v 1.96 2017/12/18 02:25:15 djm Exp $ */
+/* $OpenBSD: monitor_wrap.c,v 1.97 2017/12/21 00:00:28 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -458,7 +458,7 @@ mm_sshkey_verify(const struct sshkey *key, const u_char *sig, size_t siglen,
         buffer_put_string(&m, blob, len);
         buffer_put_string(&m, sig, siglen);
         buffer_put_string(&m, data, datalen);
-        buffer_put_cstring(&m, sigalg);
+        buffer_put_cstring(&m, sigalg == NULL ? "" : sigalg);
         free(blob);
 
         mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYVERIFY, &m);