upstream: expose PKCS#11 key labels/X.509 subjects as comments

Extract the key label or X.509 subject string when PKCS#11 keys
are retrieved from the token and plumb this through to places where
it may be used as a comment.

based on https://github.com/openssh/openssh-portable/pull/138
by Danielle Church

feedback and ok markus@

OpenBSD-Commit-ID: cae1fda10d9e10971dea29520916e27cfec7ca35

1 files changed, 13 insertions, 6 deletions

diff --git a/ssh-agent.c b/ssh-agent.c
index dd5d21d5a..6092f19dc 100644
--- a/ssh-agent.c
+++ b/ssh-agent.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-agent.c,v 1.252 2020/01/23 07:10:22 dtucker Exp $ */
+/* $OpenBSD: ssh-agent.c,v 1.253 2020/01/25 00:03:36 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -633,6 +633,7 @@ static void
 process_add_smartcard_key(SocketEntry *e)
 {
         char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
+        char **comments = NULL;
         int r, i, count = 0, success = 0, confirm = 0;
         u_int seconds;
         time_t death = 0;
@@ -682,28 +683,34 @@ process_add_smartcard_key(SocketEntry *e)
         if (lifetime && !death)
                 death = monotime() + lifetime;
 
-        count = pkcs11_add_provider(canonical_provider, pin, &keys);
+        count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
         for (i = 0; i < count; i++) {
                 k = keys[i];
                 if (lookup_identity(k) == NULL) {
                         id = xcalloc(1, sizeof(Identity));
                         id->key = k;
+                        keys[i] = NULL; /* transferred */
                         id->provider = xstrdup(canonical_provider);
-                        id->comment = xstrdup(canonical_provider); /* XXX */
+                        if (*comments[i] != '\0') {
+                                id->comment = comments[i];
+                                comments[i] = NULL; /* transferred */
+                        } else {
+                                id->comment = xstrdup(canonical_provider);
+                        }
                         id->death = death;
                         id->confirm = confirm;
                         TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
                         idtab->nentries++;
                         success = 1;
-                } else {
-                        sshkey_free(k);
                 }
-                keys[i] = NULL;
+                sshkey_free(keys[i]);
+                free(comments[i]);
         }
 send:
         free(pin);
         free(provider);
         free(keys);
+        free(comments);
         send_status(e, success);
 }