Use consistent format in debug log for keys readied, offered and

received during public key authentication.

This makes it a little easier to see what is going on, as each message
now contains the key filename, its type and fingerprint, and whether
the key is hosted in an agent or a token.

diff --git a/usr.bin/ssh/sshconnect2.c b/usr.bin/ssh/sshconnect2.c
index 957a04b..206b711 100644 (file)
--- a/usr.bin/ssh/sshconnect2.c
+++ b/usr.bin/ssh/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.284 2018/08/13 02:41:05 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.285 2018/09/14 04:17:12 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -573,6 +573,27 @@ input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh)
        return 0;
 }
 
+/*
+ * Format an identity for logging including filename, key type, fingerprint
+ * and location (agent, etc.). Caller must free.
+ */
+static char *
+format_identity(Identity *id)
+{
+       char *fp, *ret = NULL;
+
+       if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash,
+           SSH_FP_DEFAULT)) == NULL)
+               fatal("%s: sshkey_fingerprint failed", __func__);
+       xasprintf(&ret, "%s %s %s%s%s%s",
+           id->filename, sshkey_type(id->key), fp,
+           id->userprovided ? ", explicit" : "",
+           (id->key->flags & SSHKEY_FLAG_EXT) ? ", token" : "",
+           id->agent_fd != -1 ? ", agent" : "");
+       free(fp);
+       return ret;
+}
+
 /* ARGSUSED */
 int
 input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
@@ -580,9 +601,9 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
        Authctxt *authctxt = ssh->authctxt;
        struct sshkey *key = NULL;
        Identity *id = NULL;
-       int pktype, sent = 0;
+       int pktype, found = 0, sent = 0;
        size_t blen;
-       char *pkalg = NULL, *fp;
+       char *pkalg = NULL, *fp = NULL, *ident = NULL;
        u_char *pkblob = NULL;
        int r;
 
@@ -594,10 +615,8 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
            (r = sshpkt_get_end(ssh)) != 0)
                goto done;
 
-       debug("Server accepts key: pkalg %s blen %zu", pkalg, blen);
-
        if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) {
-               debug("unknown pkalg %s", pkalg);
+               debug("%s: server sent unknown pkalg %s", __func__, pkalg);
                goto done;
        }
        if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) {
@@ -610,11 +629,6 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
                    key->type, pktype);
                goto done;
        }
-       if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
-           SSH_FP_DEFAULT)) == NULL)
-               goto done;
-       debug2("input_userauth_pk_ok: fp %s", fp);
-       free(fp);
 
        /*
         * search keys in the reverse order, because last candidate has been
@@ -623,13 +637,25 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
         */
        TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
                if (sshkey_equal(key, id->key)) {
-                       sent = sign_and_send_pubkey(ssh, authctxt, id);
+                       found = 1;
                        break;
                }
        }
+       if (!found || id == NULL) {
+               fp = sshkey_fingerprint(key, options.fingerprint_hash,
+                   SSH_FP_DEFAULT);
+               error("%s: server replied with unknown key: %s %s", __func__,
+                   sshkey_type(key), fp == NULL ? "<ERROR>" : fp);
+               goto done;
+       }
+       ident = format_identity(id);
+       debug("Server accepts key: %s", ident);
+       sent = sign_and_send_pubkey(ssh, authctxt, id);
        r = 0;
  done:
        sshkey_free(key);
+       free(ident);
+       free(fp);
        free(pkalg);
        free(pkblob);
 
@@ -1450,6 +1476,7 @@ pubkey_prepare(Authctxt *authctxt)
        int agent_fd = -1, i, r, found;
        size_t j;
        struct ssh_identitylist *idlist;
+       char *ident;
 
        TAILQ_INIT(&agent);     /* keys from the agent */
        TAILQ_INIT(&files);     /* keys from the config file */
@@ -1566,10 +1593,11 @@ pubkey_prepare(Authctxt *authctxt)
                        memset(id, 0, sizeof(*id));
                        continue;
                }
-               debug2("key: %s (%p)%s%s", id->filename, id->key,
-                   id->userprovided ? ", explicit" : "",
-                   id->agent_fd != -1 ? ", agent" : "");
+               ident = format_identity(id);
+               debug("Will attempt key: %s", ident);
+               free(ident);
        }
+       debug2("%s: done", __func__);
 }
 
 static void
@@ -1617,7 +1645,7 @@ userauth_pubkey(Authctxt *authctxt)
        struct ssh *ssh = active_state; /* XXX */
        Identity *id;
        int sent = 0;
-       char *fp;
+       char *ident;
 
        while ((id = TAILQ_FIRST(&authctxt->keys))) {
                if (id->tried++)
@@ -1632,16 +1660,9 @@ userauth_pubkey(Authctxt *authctxt)
                 */
                if (id->key != NULL) {
                        if (try_identity(id)) {
-                               if ((fp = sshkey_fingerprint(id->key,
-                                   options.fingerprint_hash,
-                                   SSH_FP_DEFAULT)) == NULL) {
-                                       error("%s: sshkey_fingerprint failed",
-                                           __func__);
-                                       return 0;
-                               }
-                               debug("Offering public key: %s %s %s",
-                                   sshkey_type(id->key), fp, id->filename);
-                               free(fp);
+                               ident = format_identity(id);
+                               debug("Offering public key: %s", ident);
+                               free(ident);
                                sent = send_pubkey_test(ssh, authctxt, id);
                        }
                } else {