- return 1;
-}
-
-/*
- * Checks if the user has an authentication agent, and if so, tries to
- * authenticate using the agent.
- */
-int
-try_agent_authentication()
-{
- int status, type;
- char *comment;
- AuthenticationConnection *auth;
- unsigned char response[16];
- unsigned int i;
- BIGNUM *e, *n, *challenge;
-
- /* Get connection to the agent. */
- auth = ssh_get_authentication_connection();
- if (!auth)
- return 0;
-
- e = BN_new();
- n = BN_new();
- challenge = BN_new();
-
- /* Loop through identities served by the agent. */
- for (status = ssh_get_first_identity(auth, e, n, &comment);
- status;
- status = ssh_get_next_identity(auth, e, n, &comment)) {
- int plen, clen;
-
- /* Try this identity. */
- debug("Trying RSA authentication via agent with '%.100s'", comment);
- xfree(comment);
-
- /* Tell the server that we are willing to authenticate using this key. */
- packet_start(SSH_CMSG_AUTH_RSA);
- packet_put_bignum(n);
- packet_send();
- packet_write_wait();
-
- /* Wait for server's response. */
- type = packet_read(&plen);
-
- /* The server sends failure if it doesn\'t like our key or
- does not support RSA authentication. */
- if (type == SSH_SMSG_FAILURE) {
- debug("Server refused our key.");
- continue;
- }
- /* Otherwise it should have sent a challenge. */
- if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
- packet_disconnect("Protocol error during RSA authentication: %d",
- type);
-
- packet_get_bignum(challenge, &clen);
-
- packet_integrity_check(plen, clen, type);
-
- debug("Received RSA challenge from server.");
-
- /* Ask the agent to decrypt the challenge. */
- if (!ssh_decrypt_challenge(auth, e, n, challenge,
- session_id, 1, response)) {
- /* The agent failed to authenticate this identifier although it
- advertised it supports this. Just return a wrong value. */
- log("Authentication agent failed to decrypt challenge.");
- memset(response, 0, sizeof(response));
- }
- debug("Sending response to RSA challenge.");
-
- /* Send the decrypted challenge back to the server. */
- packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
- for (i = 0; i < 16; i++)
- packet_put_char(response[i]);
- packet_send();
- packet_write_wait();
-
- /* Wait for response from the server. */
- type = packet_read(&plen);
-
- /* The server returns success if it accepted the authentication. */
- if (type == SSH_SMSG_SUCCESS) {
- debug("RSA authentication accepted by server.");
- BN_clear_free(e);
- BN_clear_free(n);
- BN_clear_free(challenge);
- return 1;
- }
- /* Otherwise it should return failure. */
- if (type != SSH_SMSG_FAILURE)
- packet_disconnect("Protocol error waiting RSA auth response: %d",
- type);
- }
-
- BN_clear_free(e);
- BN_clear_free(n);
- BN_clear_free(challenge);
-
- debug("RSA authentication using agent refused.");
- return 0;
-}
-
-/*
- * Computes the proper response to a RSA challenge, and sends the response to
- * the server.
- */
-void
-respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv)
-{
- unsigned char buf[32], response[16];
- MD5_CTX md;
- int i, len;
-
- /* Decrypt the challenge using the private key. */
- rsa_private_decrypt(challenge, challenge, prv);
-
- /* Compute the response. */
- /* The response is MD5 of decrypted challenge plus session id. */
- len = BN_num_bytes(challenge);
- if (len <= 0 || len > sizeof(buf))
- packet_disconnect("respond_to_rsa_challenge: bad challenge length %d",
- len);
-
- memset(buf, 0, sizeof(buf));
- BN_bn2bin(challenge, buf + sizeof(buf) - len);
- MD5_Init(&md);
- MD5_Update(&md, buf, 32);
- MD5_Update(&md, session_id, 16);
- MD5_Final(response, &md);
-
- debug("Sending response to host key RSA challenge.");
-
- /* Send the response back to the server. */
- packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
- for (i = 0; i < 16; i++)
- packet_put_char(response[i]);
- packet_send();
- packet_write_wait();
-
- memset(buf, 0, sizeof(buf));
- memset(response, 0, sizeof(response));
- memset(&md, 0, sizeof(md));
-}
-
-/*
- * Checks if the user has authentication file, and if so, tries to authenticate
- * the user using it.
- */
-int
-try_rsa_authentication(struct passwd * pw, const char *authfile)
-{
- extern Options options;
- BIGNUM *challenge;
- RSA *private_key;
- RSA *public_key;
- char *passphrase, *comment;
- int type, i;
- int plen, clen;
-
- /* Try to load identification for the authentication key. */
- public_key = RSA_new();
- if (!load_public_key(authfile, public_key, &comment)) {
- RSA_free(public_key);
- return 0; /* Could not load it. Fail. */
- }
- debug("Trying RSA authentication with key '%.100s'", comment);
-
- /* Tell the server that we are willing to authenticate using this key. */
- packet_start(SSH_CMSG_AUTH_RSA);
- packet_put_bignum(public_key->n);
- packet_send();
- packet_write_wait();
-
- /* We no longer need the public key. */
- RSA_free(public_key);
-
- /* Wait for server's response. */
- type = packet_read(&plen);
-
- /* The server responds with failure if it doesn\'t like our key or
- doesn\'t support RSA authentication. */
- if (type == SSH_SMSG_FAILURE) {
- debug("Server refused our key.");
- xfree(comment);
- return 0; /* Server refuses to authenticate with
- this key. */
- }
- /* Otherwise, the server should respond with a challenge. */
- if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
- packet_disconnect("Protocol error during RSA authentication: %d", type);
-
- /* Get the challenge from the packet. */
- challenge = BN_new();
- packet_get_bignum(challenge, &clen);
-
- packet_integrity_check(plen, clen, type);
-
- debug("Received RSA challenge from server.");
-
- private_key = RSA_new();
- /* Load the private key. Try first with empty passphrase; if it
- fails, ask for a passphrase. */
- if (!load_private_key(authfile, "", private_key, NULL)) {
- char buf[300];
- snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ",
- comment);
- if (!options.batch_mode)
- passphrase = read_passphrase(buf, 0);
- else {
- debug("Will not query passphrase for %.100s in batch mode.",
- comment);
- passphrase = xstrdup("");
- }
-
- /* Load the authentication file using the pasphrase. */
- if (!load_private_key(authfile, passphrase, private_key, NULL)) {
- memset(passphrase, 0, strlen(passphrase));
- xfree(passphrase);
- error("Bad passphrase.");
-
- /* Send a dummy response packet to avoid protocol error. */
- packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
- for (i = 0; i < 16; i++)
- packet_put_char(0);
- packet_send();
- packet_write_wait();
-
- /* Expect the server to reject it... */
- packet_read_expect(&plen, SSH_SMSG_FAILURE);
- xfree(comment);
- return 0;
- }
- /* Destroy the passphrase. */
- memset(passphrase, 0, strlen(passphrase));
- xfree(passphrase);
- }
- /* We no longer need the comment. */
- xfree(comment);
-
- /* Compute and send a response to the challenge. */
- respond_to_rsa_challenge(challenge, private_key);
-
- /* Destroy the private key. */
- RSA_free(private_key);
-
- /* We no longer need the challenge. */
- BN_clear_free(challenge);
-
- /* Wait for response from the server. */
- type = packet_read(&plen);
- if (type == SSH_SMSG_SUCCESS) {
- debug("RSA authentication accepted by server.");
- return 1;
- }
- if (type != SSH_SMSG_FAILURE)
- packet_disconnect("Protocol error waiting RSA auth response: %d", type);
- debug("RSA authentication refused.");
- return 0;
-}
-
-/*
- * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv
- * authentication and RSA host authentication.
- */
-int
-try_rhosts_rsa_authentication(const char *local_user, RSA * host_key)
-{
- int type;
- BIGNUM *challenge;
- int plen, clen;
-
- debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication.");
-
- /* Tell the server that we are willing to authenticate using this key. */
- packet_start(SSH_CMSG_AUTH_RHOSTS_RSA);
- packet_put_string(local_user, strlen(local_user));
- packet_put_int(BN_num_bits(host_key->n));
- packet_put_bignum(host_key->e);
- packet_put_bignum(host_key->n);
- packet_send();
- packet_write_wait();
-
- /* Wait for server's response. */
- type = packet_read(&plen);
-
- /* The server responds with failure if it doesn't admit our
- .rhosts authentication or doesn't know our host key. */
- if (type == SSH_SMSG_FAILURE) {
- debug("Server refused our rhosts authentication or host key.");
- return 0;
- }
- /* Otherwise, the server should respond with a challenge. */
- if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
- packet_disconnect("Protocol error during RSA authentication: %d", type);
-
- /* Get the challenge from the packet. */
- challenge = BN_new();
- packet_get_bignum(challenge, &clen);
-
- packet_integrity_check(plen, clen, type);
-
- debug("Received RSA challenge for host key from server.");
-
- /* Compute a response to the challenge. */
- respond_to_rsa_challenge(challenge, host_key);
-
- /* We no longer need the challenge. */
- BN_clear_free(challenge);
-
- /* Wait for response from the server. */
- type = packet_read(&plen);
- if (type == SSH_SMSG_SUCCESS) {
- debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server.");
- return 1;
- }
- if (type != SSH_SMSG_FAILURE)
- packet_disconnect("Protocol error waiting RSA auth response: %d", type);
- debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused.");
- return 0;
-}
-
-#ifdef KRB4
-int
-try_kerberos_authentication()
-{
- KTEXT_ST auth; /* Kerberos data */
- char *reply;
- char inst[INST_SZ];
- char *realm;
- CREDENTIALS cred;
- int r, type, plen;
- Key_schedule schedule;
- u_long checksum, cksum;
- MSG_DAT msg_data;
- struct sockaddr_in local, foreign;
- struct stat st;
-
- /* Don't do anything if we don't have any tickets. */
- if (stat(tkt_string(), &st) < 0)
- return 0;
-
- strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ);
-
- realm = (char *) krb_realmofhost(get_canonical_hostname());
- if (!realm) {
- debug("Kerberos V4: no realm for %s", get_canonical_hostname());
- return 0;
- }
- /* This can really be anything. */
- checksum = (u_long) getpid();
-
- r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum);
- if (r != KSUCCESS) {
- debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]);
- return 0;
- }
- /* Get session key to decrypt the server's reply with. */
- r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred);
- if (r != KSUCCESS) {
- debug("get_cred failed: %s", krb_err_txt[r]);
- return 0;
- }
- des_key_sched((des_cblock *) cred.session, schedule);
-
- /* Send authentication info to server. */
- packet_start(SSH_CMSG_AUTH_KERBEROS);
- packet_put_string((char *) auth.dat, auth.length);
- packet_send();
- packet_write_wait();
-
- /* Zero the buffer. */
- (void) memset(auth.dat, 0, MAX_KTXT_LEN);
-
- r = sizeof(local);
- memset(&local, 0, sizeof(local));
- if (getsockname(packet_get_connection_in(),
- (struct sockaddr *) & local, &r) < 0)
- debug("getsockname failed: %s", strerror(errno));
-
- r = sizeof(foreign);
- memset(&foreign, 0, sizeof(foreign));
- if (getpeername(packet_get_connection_in(),
- (struct sockaddr *) & foreign, &r) < 0) {
- debug("getpeername failed: %s", strerror(errno));
- fatal_cleanup();
- }
- /* Get server reply. */
- type = packet_read(&plen);
- switch (type) {
- case SSH_SMSG_FAILURE:
- /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
- debug("Kerberos V4 authentication failed.");
- return 0;
- break;
-
- case SSH_SMSG_AUTH_KERBEROS_RESPONSE:
- /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
- debug("Kerberos V4 authentication accepted.");
-
- /* Get server's response. */
- reply = packet_get_string((unsigned int *) &auth.length);
- memcpy(auth.dat, reply, auth.length);
- xfree(reply);
-
- packet_integrity_check(plen, 4 + auth.length, type);
-
- /* If his response isn't properly encrypted with the
- session key, and the decrypted checksum fails to match,
- he's bogus. Bail out. */
- r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,
- &foreign, &local, &msg_data);
- if (r != KSUCCESS) {
- debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]);
- packet_disconnect("Kerberos V4 challenge failed!");
- }
- /* Fetch the (incremented) checksum that we supplied in the request. */
- (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum));
- cksum = ntohl(cksum);
-
- /* If it matches, we're golden. */
- if (cksum == checksum + 1) {
- debug("Kerberos V4 challenge successful.");
- return 1;
- } else
- packet_disconnect("Kerberos V4 challenge failed!");
- break;
-
- default:
- packet_disconnect("Protocol error on Kerberos V4 response: %d", type);
- }