upstream: require FIDO application strings to start with "ssh:"; ok

markus@

OpenBSD-Commit-ID: 94e9c1c066d42b76f035a3d58250a32b14000afb

2 files changed, 9 insertions, 3 deletions

diff --git a/ssh-keygen.1 b/ssh-keygen.1
index f0e76aab1..51aee21aa 100644
--- a/ssh-keygen.1
+++ b/ssh-keygen.1
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: ssh-keygen.1,v 1.199 2020/02/03 08:15:37 jmc Exp $
+.\"     $OpenBSD: ssh-keygen.1,v 1.200 2020/02/04 09:58:04 djm Exp $
 .\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -35,7 +35,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: February 3 2020 $
+.Dd $Mdocdate: February 4 2020 $
 .Dt SSH-KEYGEN 1
 .Os
 .Sh NAME
@@ -472,6 +472,8 @@ Those supported at present are:
 Override the default FIDO application/origin string of
 .Dq ssh: .
 This may be useful when generating host or domain-specific resident keys.
+The specified application string must begin with
+.Dq ssh: .
 .It Cm challenge Ns = Ns Ar path
 Specifies a path to a challenge string that will be passed to the
 FIDO token during key generation.
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]);