+ /*
+ * OK, we're now sitting on a USERAUTH_FAILURE message, so
+ * we can look at the string in it and know what we can
+ * helpfully try next.
+ */
+ {
+ char *methods;
+ int methlen;
+ ssh2_pkt_getstring(&methods, &methlen);
+ if (!ssh2_pkt_getbool()) {
+ /*
+ * FIXME: these messages are often inappropriate.
+ */
+ c_write("Access denied\r\n", 15);
+ logevent("Access denied");
+ } else {
+ c_write("Authentication partially successful\r\n", 37);
+ logevent("Authentication partially successful");
+ }
+
+ can_pubkey = in_commasep_string("publickey", methods, methlen);
+ can_passwd = in_commasep_string("password", methods, methlen);
+ }
+
+ method = 0;
+
+ if (!method && can_pubkey && *cfg.keyfile && !tried_pubkey_config) {
+ unsigned char *pub_blob;
+ char *algorithm, *comment;
+ int pub_blob_len;
+
+ tried_pubkey_config = TRUE;
+
+ /*
+ * Try the public key supplied in the configuration.
+ *
+ * First, offer the public blob to see if the server is
+ * willing to accept it.
+ */
+ pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
+ &pub_blob_len);
+ if (pub_blob) {
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("publickey");/* method */
+ ssh2_pkt_addbool(FALSE); /* no signature included */
+ ssh2_pkt_addstring(algorithm);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
+ ssh2_pkt_send();
+ logevent("Offered public key"); /* FIXME */
+
+ crWaitUntilV(ispkt);
+ if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
+ gotit = TRUE;
+ continue; /* key refused; give up on it */
+ }
+
+ logevent("Offer of public key accepted");
+ /*
+ * Actually attempt a serious authentication using
+ * the key.
+ */
+ if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
+ sprintf(pwprompt, "Passphrase for key \"%.100s\": ", comment);
+ need_pw = TRUE;
+ } else {
+ need_pw = FALSE;
+ }
+ method = AUTH_PUBLICKEY_FILE;
+ }
+ }
+
+ if (!method && can_passwd) {
+ method = AUTH_PASSWORD;
+ sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost);
+ need_pw = TRUE;
+ }
+
+ if (need_pw) {
+ if (ssh_get_password) {
+ if (!ssh_get_password(pwprompt, password, sizeof(password))) {
+ /*
+ * get_password failed to get a password (for
+ * example because one was supplied on the command
+ * line which has already failed to work).
+ * Terminate.
+ */
+ logevent("No more passwords to try");
+ ssh_state = SSH_STATE_CLOSED;
+ crReturnV;
+ }
+ } else {
+ static int pos = 0;
+ static char c;
+
+ c_write(pwprompt, strlen(pwprompt));
+ ssh_send_ok = 1;
+
+ pos = 0;
+ while (pos >= 0) {
+ crWaitUntilV(!ispkt);
+ while (inlen--) switch (c = *in++) {
+ case 10: case 13:
+ password[pos] = 0;
+ pos = -1;
+ break;
+ case 8: case 127:
+ if (pos > 0)
+ pos--;
+ break;
+ case 21: case 27:
+ pos = 0;
+ break;
+ case 3: case 4:
+ random_save_seed();
+ exit(0);
+ break;
+ default:
+ if (((c >= ' ' && c <= '~') ||
+ ((unsigned char)c >= 160)) && pos < 40)
+ password[pos++] = c;
+ break;
+ }
+ }
+ c_write("\r\n", 2);
+ }
+ }
+
+ if (method == AUTH_PUBLICKEY_FILE) {
+ /*
+ * We have our passphrase. Now try the actual authentication.
+ */
+ struct ssh2_userkey *key;
+
+ key = ssh2_load_userkey(cfg.keyfile, password);
+ if (key == SSH2_WRONG_PASSPHRASE) {
+ c_write("Wrong passphrase\r\n", 18);
+ tried_pubkey_config = FALSE;
+ /* Send a spurious AUTH_NONE to return to the top. */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("none"); /* method */
+ ssh2_pkt_send();
+ } else if (key == NULL) {
+ c_write("Unable to load private key\r\n",28);
+ tried_pubkey_config = TRUE;
+ /* Send a spurious AUTH_NONE to return to the top. */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("none"); /* method */
+ ssh2_pkt_send();
+ } else {
+ unsigned char *blob, *sigdata;
+ int blob_len, sigdata_len;
+
+ /*
+ * We have loaded the private key and the server
+ * has announced that it's willing to accept it.
+ * Hallelujah. Generate a signature and send it.
+ */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("publickey"); /* method */
+ ssh2_pkt_addbool(TRUE);
+ ssh2_pkt_addstring(key->alg->name);
+ blob = key->alg->public_blob(key->data, &blob_len);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(blob, blob_len);
+ sfree(blob);
+
+ /*
+ * The data to be signed is:
+ *
+ * string session-id
+ *
+ * followed by everything so far placed in the
+ * outgoing packet.
+ */
+ sigdata_len = pktout.length - 5 + 4 + 20;
+ sigdata = smalloc(sigdata_len);
+ PUT_32BIT(sigdata, 20);
+ memcpy(sigdata+4, ssh2_session_id, 20);
+ memcpy(sigdata+24, pktout.data+5, pktout.length-5);
+ blob = key->alg->sign(key->data, sigdata, sigdata_len, &blob_len);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(blob, blob_len);
+ sfree(blob);
+ sfree(sigdata);
+
+ ssh2_pkt_send();
+ }
+ } else if (method == AUTH_PASSWORD) {
+ /*
+ * We send the password packet lumped tightly together with
+ * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
+ * string long enough to make the total length of the two
+ * packets constant. This should ensure that a passive
+ * listener doing traffic analyis can't work out the length
+ * of the password.
+ *
+ * For this to work, we need an assumption about the
+ * maximum length of the password packet. I think 256 is
+ * pretty conservative. Anyone using a password longer than
+ * that probably doesn't have much to worry about from
+ * people who find out how long their password is!
+ */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("password");
+ ssh2_pkt_addbool(FALSE);
+ ssh2_pkt_addstring(password);
+ ssh2_pkt_defer();
+ /*
+ * We'll include a string that's an exact multiple of the
+ * cipher block size. If the cipher is NULL for some
+ * reason, we don't do this trick at all because we gain
+ * nothing by it.
+ */
+ if (cscipher) {
+ int i, j;
+ ssh2_pkt_init(SSH2_MSG_IGNORE);
+ ssh2_pkt_addstring_start();
+ for (i = deferred_len; i <= 256; i += cscipher->blksize) {
+ for (j = 0; j < cscipher->blksize; j++) {
+ char c = (char)random_byte();
+ ssh2_pkt_addstring_data(&c, 1);
+ }
+ }
+ ssh2_pkt_defer();
+ }
+ ssh2_pkt_defersend();
+ } else {
+ c_write("No supported authentication methods left to try!\r\n", 50);
+ logevent("No supported authentications offered. Disconnecting");
+ ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+ ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
+ ssh2_pkt_addstring("No supported authentication methods available");
+ ssh2_pkt_addstring("en"); /* language tag */
+ ssh2_pkt_send();
+ ssh_state = SSH_STATE_CLOSED;
+ crReturnV;
+ }