+
+ /*
+ * Misc one-time setup for authentication.
+ */
+ s->publickey_blob = NULL;
+ if (!s->we_are_in) {
+
+ /*
+ * Load the public half of any configured public key file
+ * for later use.
+ */
+ if (!filename_is_null(ssh->cfg.keyfile)) {
+ int keytype;
+ logeventf(ssh, "Reading private key file \"%.150s\"",
+ filename_to_str(&ssh->cfg.keyfile));
+ keytype = key_type(&ssh->cfg.keyfile);
+ if (keytype == SSH_KEYTYPE_SSH2) {
+ const char *error;
+ s->publickey_blob =
+ ssh2_userkey_loadpub(&ssh->cfg.keyfile,
+ &s->publickey_algorithm,
+ &s->publickey_bloblen,
+ &s->publickey_comment, &error);
+ if (s->publickey_blob) {
+ s->publickey_encrypted =
+ ssh2_userkey_encrypted(&ssh->cfg.keyfile, NULL);
+ } else {
+ char *msgbuf;
+ logeventf(ssh, "Unable to load private key (%s)",
+ error);
+ msgbuf = dupprintf("Unable to load private key file "
+ "\"%.150s\" (%s)\r\n",
+ filename_to_str(&ssh->cfg.keyfile),
+ error);
+ c_write_str(ssh, msgbuf);
+ sfree(msgbuf);
+ }
+ } else {
+ char *msgbuf;
+ logeventf(ssh, "Unable to use this key file (%s)",
+ key_type_to_str(keytype));
+ msgbuf = dupprintf("Unable to use key file \"%.150s\""
+ " (%s)\r\n",
+ filename_to_str(&ssh->cfg.keyfile),
+ key_type_to_str(keytype));
+ c_write_str(ssh, msgbuf);
+ sfree(msgbuf);
+ s->publickey_blob = NULL;
+ }
+ }
+
+ /*
+ * Find out about any keys Pageant has (but if there's a
+ * public key configured, filter out all others).
+ */
+ s->nkeys = 0;
+ s->agent_response = NULL;
+ s->pkblob_in_agent = NULL;
+ if (ssh->cfg.tryagent && agent_exists()) {
+
+ void *r;
+
+ logevent("Pageant is running. Requesting keys.");
+
+ /* Request the keys held by the agent. */
+ PUT_32BIT(s->agent_request, 1);
+ s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
+ if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
+ ssh_agent_callback, ssh)) {
+ do {
+ crReturnV;
+ if (pktin) {
+ bombout(("Unexpected data from server while"
+ " waiting for agent response"));
+ crStopV;
+ }
+ } while (pktin || inlen > 0);
+ r = ssh->agent_response;
+ s->agent_responselen = ssh->agent_response_len;
+ }
+ s->agent_response = (unsigned char *) r;
+ if (s->agent_response && s->agent_responselen >= 5 &&
+ s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
+ int keyi;
+ unsigned char *p;
+ p = s->agent_response + 5;
+ s->nkeys = GET_32BIT(p);
+ p += 4;
+ logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
+ if (s->publickey_blob) {
+ /* See if configured key is in agent. */
+ for (keyi = 0; keyi < s->nkeys; keyi++) {
+ s->pklen = GET_32BIT(p);
+ if (s->pklen == s->publickey_bloblen &&
+ !memcmp(p+4, s->publickey_blob,
+ s->publickey_bloblen)) {
+ logeventf(ssh, "Pageant key #%d matches "
+ "configured key file", keyi);
+ s->keyi = keyi;
+ s->pkblob_in_agent = p;
+ break;
+ }
+ p += 4 + s->pklen;
+ p += GET_32BIT(p) + 4; /* comment */
+ }
+ if (!s->pkblob_in_agent) {
+ logevent("Configured key file not in Pageant");
+ s->nkeys = 0;
+ }
+ }
+ }
+ }
+
+ }
+
+ /*
+ * We repeat this whole loop, including the username prompt,
+ * until we manage a successful authentication. If the user
+ * types the wrong _password_, they can be sent back to the
+ * beginning to try another username, if this is configured on.
+ * (If they specify a username in the config, they are never
+ * asked, even if they do give a wrong password.)
+ *
+ * I think this best serves the needs of
+ *
+ * - the people who have no configuration, no keys, and just
+ * want to try repeated (username,password) pairs until they
+ * type both correctly
+ *
+ * - people who have keys and configuration but occasionally
+ * need to fall back to passwords
+ *
+ * - people with a key held in Pageant, who might not have
+ * logged in to a particular machine before; so they want to
+ * type a username, and then _either_ their key will be
+ * accepted, _or_ they will type a password. If they mistype
+ * the username they will want to be able to get back and
+ * retype it!
+ */
+ s->username[0] = '\0';
+ s->got_username = FALSE;
+ while (!s->we_are_in) {
+ /*