+ packet_check_eom(); /* done with parsing incoming message. */
+
+ packet_add_padding(64);
+ packet_send();
+}
+
+static int
+ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
+ u_char *data, u_int datalen)
+{
+ Buffer b;
+ struct stat st;
+ pid_t pid;
+ int to[2], from[2], status, version = 2;
+
+ debug2("ssh_keysign called");
+
+ if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
+ error("ssh_keysign: no installed: %s", strerror(errno));
+ return -1;
+ }
+ if (fflush(stdout) != 0)
+ error("ssh_keysign: fflush: %s", strerror(errno));
+ if (pipe(to) < 0) {
+ error("ssh_keysign: pipe: %s", strerror(errno));
+ return -1;
+ }
+ if (pipe(from) < 0) {
+ error("ssh_keysign: pipe: %s", strerror(errno));
+ return -1;
+ }
+ if ((pid = fork()) < 0) {
+ error("ssh_keysign: fork: %s", strerror(errno));
+ return -1;
+ }
+ if (pid == 0) {
+ seteuid(getuid());
+ setuid(getuid());
+ close(from[0]);
+ if (dup2(from[1], STDOUT_FILENO) < 0)
+ fatal("ssh_keysign: dup2: %s", strerror(errno));
+ close(to[1]);
+ if (dup2(to[0], STDIN_FILENO) < 0)
+ fatal("ssh_keysign: dup2: %s", strerror(errno));
+ close(from[1]);
+ close(to[0]);
+ execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
+ fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
+ strerror(errno));
+ }
+ close(from[1]);
+ close(to[0]);
+
+ buffer_init(&b);
+ buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
+ buffer_put_string(&b, data, datalen);
+ ssh_msg_send(to[1], version, &b);
+
+ if (ssh_msg_recv(from[0], &b) < 0) {
+ error("ssh_keysign: no reply");
+ buffer_clear(&b);
+ return -1;
+ }
+ close(from[0]);
+ close(to[1]);
+
+ while (waitpid(pid, &status, 0) < 0)
+ if (errno != EINTR)
+ break;
+
+ if (buffer_get_char(&b) != version) {
+ error("ssh_keysign: bad version");
+ buffer_clear(&b);
+ return -1;
+ }
+ *sigp = buffer_get_string(&b, lenp);
+ buffer_clear(&b);
+
+ return 0;
+}
+
+int
+userauth_hostbased(Authctxt *authctxt)
+{
+ Key *private = NULL;
+ Sensitive *sensitive = authctxt->sensitive;
+ Buffer b;
+ u_char *signature, *blob;
+ char *chost, *pkalg, *p;
+ const char *service;
+ u_int blen, slen;
+ int ok, i, len, found = 0;
+
+ /* check for a useful key */
+ for (i = 0; i < sensitive->nkeys; i++) {
+ private = sensitive->keys[i];
+ if (private && private->type != KEY_RSA1) {
+ found = 1;
+ /* we take and free the key */
+ sensitive->keys[i] = NULL;
+ break;
+ }
+ }
+ if (!found) {
+ debug("No more client hostkeys for hostbased authentication.");
+ return 0;
+ }
+ if (key_to_blob(private, &blob, &blen) == 0) {
+ key_free(private);
+ return 0;
+ }
+ /* figure out a name for the client host */
+ p = get_local_name(packet_get_connection_in());
+ if (p == NULL) {
+ error("userauth_hostbased: cannot get local ipaddr/name");
+ key_free(private);
+ return 0;
+ }
+ len = strlen(p) + 2;
+ chost = xmalloc(len);
+ strlcpy(chost, p, len);
+ strlcat(chost, ".", len);
+ debug2("userauth_hostbased: chost %s", chost);
+ xfree(p);
+
+ service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
+ authctxt->service;
+ pkalg = xstrdup(key_ssh_name(private));
+ buffer_init(&b);
+ /* construct data */
+ buffer_put_string(&b, session_id2, session_id2_len);
+ buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
+ buffer_put_cstring(&b, authctxt->server_user);
+ buffer_put_cstring(&b, service);
+ buffer_put_cstring(&b, authctxt->method->name);
+ buffer_put_cstring(&b, pkalg);
+ buffer_put_string(&b, blob, blen);
+ buffer_put_cstring(&b, chost);
+ buffer_put_cstring(&b, authctxt->local_user);
+#ifdef DEBUG_PK
+ buffer_dump(&b);
+#endif
+ if (sensitive->external_keysign)
+ ok = ssh_keysign(private, &signature, &slen,
+ buffer_ptr(&b), buffer_len(&b));
+ else
+ ok = key_sign(private, &signature, &slen,
+ buffer_ptr(&b), buffer_len(&b));
+ key_free(private);
+ buffer_free(&b);
+ if (ok != 0) {
+ error("key_sign failed");
+ xfree(chost);
+ xfree(pkalg);
+ return 0;
+ }
+ packet_start(SSH2_MSG_USERAUTH_REQUEST);
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
+ packet_put_cstring(pkalg);
+ packet_put_string(blob, blen);
+ packet_put_cstring(chost);
+ packet_put_cstring(authctxt->local_user);
+ packet_put_string(signature, slen);
+ memset(signature, 's', slen);
+ xfree(signature);
+ xfree(chost);
+ xfree(pkalg);