upstream: security keys typically need to be tapped/touched in

order to perform a signature operation. Notify the user when this is expected
via the TTY (if available) or $SSH_ASKPASS if we can.

ok markus@

OpenBSD-Commit-ID: 0ef90a99a85d4a2a07217a58efb4df8444818609

1 files changed, 11 insertions, 3 deletions

diff --git a/ssh-keygen.c b/ssh-keygen.c
index 7b8dce7d8..46d642e17 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.362 2019/11/12 19:33:08 markus Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.363 2019/11/12 22:36:44 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -2506,8 +2506,7 @@ sign_one(struct sshkey *signkey, const char *filename, int fd,
 {
         struct sshbuf *sigbuf = NULL, *abuf = NULL;
         int r = SSH_ERR_INTERNAL_ERROR, wfd = -1, oerrno;
-        char *wfile = NULL;
-        char *asig = NULL;
+        char *wfile = NULL, *asig = NULL, *fp = NULL;
 
         if (!quiet) {
                 if (fd == STDIN_FILENO)
@@ -2515,6 +2514,15 @@ sign_one(struct sshkey *signkey, const char *filename, int fd,
                 else
                         fprintf(stderr, "Signing file %s\n", filename);
         }
+        if (signer == NULL && sshkey_is_sk(signkey) &&
+            (signkey->sk_flags & SSH_SK_USER_PRESENCE_REQD)) {
+                if ((fp = sshkey_fingerprint(signkey, fingerprint_hash,
+                    SSH_FP_DEFAULT)) == NULL)
+                        fatal("%s: sshkey_fingerprint failed", __func__);
+                fprintf(stderr, "Confirm user presence for key %s %s\n",
+                    sshkey_type(signkey), fp);
+                free(fp);
+        }
         if ((r = sshsig_sign_fd(signkey, NULL, sk_provider, fd, sig_namespace,
             &sigbuf, signer, signer_ctx)) != 0) {
                 error("Signing %s failed: %s", filename, ssh_err(r));