1 files changed, 5 insertions, 1 deletions

diff --git a/ssh-keygen.c b/ssh-keygen.c
index 4ee43ab98..2a64622c1 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.395 2020/01/28 08:01:34 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.396 2020/02/04 09:58:04 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -3572,6 +3572,10 @@ main(int argc, char **argv)
                         } else if (strncasecmp(opts[i],
                             "application=", 12) == 0) {
                                 sk_application = xstrdup(opts[i] + 12);
+                                if (strncmp(sk_application, "ssh:", 4) != 0) {
+                                        fatal("FIDO application string must "
+                                            "begin with \"ssh:\"");
+                                }
                         } else {
                                 fatal("Option \"%s\" is unsupported for "
                                     "FIDO authenticator enrollment", opts[i]);