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authorDamien Miller <djm@mindrot.org>1999-10-27 13:42:43 +1000
committerDamien Miller <djm@mindrot.org>1999-10-27 13:42:43 +1000
commitd4a8b7e34dd619a4debf9a206c81db26d1402ea6 (patch)
treea47d770a2f790f40d18b0982d4e55fa7cfb1fa3b /sshconnect.c
Initial revision
Diffstat (limited to 'sshconnect.c')
-rw-r--r--sshconnect.c1495
1 files changed, 1495 insertions, 0 deletions
diff --git a/sshconnect.c b/sshconnect.c
new file mode 100644
index 00000000..3437b04c
--- /dev/null
+++ b/sshconnect.c
@@ -0,0 +1,1495 @@
+/*
+
+sshconnect.c
+
+Author: Tatu Ylonen <ylo@cs.hut.fi>
+
+Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ All rights reserved
+
+Created: Sat Mar 18 22:15:47 1995 ylo
+
+Code to connect to a remote host, and to perform the client side of the
+login (authentication) dialog.
+
+*/
+
+#include "includes.h"
+RCSID("$Id: sshconnect.c,v 1.1 1999/10/27 03:42:45 damien Exp $");
+
+#include <openssl/bn.h>
+#include "xmalloc.h"
+#include "rsa.h"
+#include "ssh.h"
+#include "packet.h"
+#include "authfd.h"
+#include "cipher.h"
+#include "mpaux.h"
+#include "uidswap.h"
+#include "compat.h"
+
+#include <openssl/md5.h>
+
+/* Session id for the current session. */
+unsigned char session_id[16];
+
+/* Connect to the given ssh server using a proxy command. */
+
+int
+ssh_proxy_connect(const char *host, int port, uid_t original_real_uid,
+ const char *proxy_command)
+{
+ Buffer command;
+ const char *cp;
+ char *command_string;
+ int pin[2], pout[2];
+ int pid;
+ char portstring[100];
+
+ /* Convert the port number into a string. */
+ snprintf(portstring, sizeof portstring, "%d", port);
+
+ /* Build the final command string in the buffer by making the appropriate
+ substitutions to the given proxy command. */
+ buffer_init(&command);
+ for (cp = proxy_command; *cp; cp++)
+ {
+ if (cp[0] == '%' && cp[1] == '%')
+ {
+ buffer_append(&command, "%", 1);
+ cp++;
+ continue;
+ }
+ if (cp[0] == '%' && cp[1] == 'h')
+ {
+ buffer_append(&command, host, strlen(host));
+ cp++;
+ continue;
+ }
+ if (cp[0] == '%' && cp[1] == 'p')
+ {
+ buffer_append(&command, portstring, strlen(portstring));
+ cp++;
+ continue;
+ }
+ buffer_append(&command, cp, 1);
+ }
+ buffer_append(&command, "\0", 1);
+
+ /* Get the final command string. */
+ command_string = buffer_ptr(&command);
+
+ /* Create pipes for communicating with the proxy. */
+ if (pipe(pin) < 0 || pipe(pout) < 0)
+ fatal("Could not create pipes to communicate with the proxy: %.100s",
+ strerror(errno));
+
+ debug("Executing proxy command: %.500s", command_string);
+
+ /* Fork and execute the proxy command. */
+ if ((pid = fork()) == 0)
+ {
+ char *argv[10];
+
+ /* Child. Permanently give up superuser privileges. */
+ permanently_set_uid(original_real_uid);
+
+ /* Redirect stdin and stdout. */
+ close(pin[1]);
+ if (pin[0] != 0)
+ {
+ if (dup2(pin[0], 0) < 0)
+ perror("dup2 stdin");
+ close(pin[0]);
+ }
+ close(pout[0]);
+ if (dup2(pout[1], 1) < 0)
+ perror("dup2 stdout");
+ close(pout[1]); /* Cannot be 1 because pin allocated two descriptors. */
+
+ /* Stderr is left as it is so that error messages get printed on
+ the user's terminal. */
+ argv[0] = "/bin/sh";
+ argv[1] = "-c";
+ argv[2] = command_string;
+ argv[3] = NULL;
+
+ /* Execute the proxy command. Note that we gave up any extra
+ privileges above. */
+ execv("/bin/sh", argv);
+ perror("/bin/sh");
+ exit(1);
+ }
+ /* Parent. */
+ if (pid < 0)
+ fatal("fork failed: %.100s", strerror(errno));
+
+ /* Close child side of the descriptors. */
+ close(pin[0]);
+ close(pout[1]);
+
+ /* Free the command name. */
+ buffer_free(&command);
+
+ /* Set the connection file descriptors. */
+ packet_set_connection(pout[0], pin[1]);
+
+ return 1;
+}
+
+/* Creates a (possibly privileged) socket for use as the ssh connection. */
+
+int ssh_create_socket(uid_t original_real_uid, int privileged)
+{
+ int sock;
+
+ /* If we are running as root and want to connect to a privileged port,
+ bind our own socket to a privileged port. */
+ if (privileged)
+ {
+ int p = IPPORT_RESERVED - 1;
+
+ sock = rresvport(&p);
+ if (sock < 0)
+ fatal("rresvport: %.100s", strerror(errno));
+ debug("Allocated local port %d.", p);
+ }
+ else
+ {
+ /* Just create an ordinary socket on arbitrary port. We use the
+ user's uid to create the socket. */
+ temporarily_use_uid(original_real_uid);
+ sock = socket(AF_INET, SOCK_STREAM, 0);
+ if (sock < 0)
+ fatal("socket: %.100s", strerror(errno));
+ restore_uid();
+ }
+ return sock;
+}
+
+/* Opens a TCP/IP connection to the remote server on the given host. If
+ port is 0, the default port will be used. If anonymous is zero,
+ a privileged port will be allocated to make the connection.
+ This requires super-user privileges if anonymous is false.
+ Connection_attempts specifies the maximum number of tries (one per
+ second). If proxy_command is non-NULL, it specifies the command (with %h
+ and %p substituted for host and port, respectively) to use to contact
+ the daemon. */
+
+int ssh_connect(const char *host, struct sockaddr_in *hostaddr,
+ int port, int connection_attempts,
+ int anonymous, uid_t original_real_uid,
+ const char *proxy_command)
+{
+ int sock = -1, attempt, i;
+ int on = 1;
+ struct servent *sp;
+ struct hostent *hp;
+ struct linger linger;
+
+ debug("ssh_connect: getuid %d geteuid %d anon %d",
+ (int)getuid(), (int)geteuid(), anonymous);
+
+ /* Get default port if port has not been set. */
+ if (port == 0)
+ {
+ sp = getservbyname(SSH_SERVICE_NAME, "tcp");
+ if (sp)
+ port = ntohs(sp->s_port);
+ else
+ port = SSH_DEFAULT_PORT;
+ }
+
+ /* If a proxy command is given, connect using it. */
+ if (proxy_command != NULL)
+ return ssh_proxy_connect(host, port, original_real_uid, proxy_command);
+
+ /* No proxy command. */
+
+ /* No host lookup made yet. */
+ hp = NULL;
+
+ /* Try to connect several times. On some machines, the first time will
+ sometimes fail. In general socket code appears to behave quite
+ magically on many machines. */
+ for (attempt = 0; attempt < connection_attempts; attempt++)
+ {
+ if (attempt > 0)
+ debug("Trying again...");
+
+ /* Try to parse the host name as a numeric inet address. */
+ memset(hostaddr, 0, sizeof(hostaddr));
+ hostaddr->sin_family = AF_INET;
+ hostaddr->sin_port = htons(port);
+ hostaddr->sin_addr.s_addr = inet_addr(host);
+ if ((hostaddr->sin_addr.s_addr & 0xffffffff) != 0xffffffff)
+ {
+ /* Valid numeric IP address */
+ debug("Connecting to %.100s port %d.",
+ inet_ntoa(hostaddr->sin_addr), port);
+
+ /* Create a socket. */
+ sock = ssh_create_socket(original_real_uid,
+ !anonymous && geteuid() == 0 &&
+ port < IPPORT_RESERVED);
+
+ /* Connect to the host. We use the user's uid in the hope that
+ it will help with the problems of tcp_wrappers showing the
+ remote uid as root. */
+ temporarily_use_uid(original_real_uid);
+ if (connect(sock, (struct sockaddr *)hostaddr, sizeof(*hostaddr))
+ >= 0)
+ {
+ /* Successful connect. */
+ restore_uid();
+ break;
+ }
+ debug("connect: %.100s", strerror(errno));
+ restore_uid();
+
+ /* Destroy the failed socket. */
+ shutdown(sock, SHUT_RDWR);
+ close(sock);
+ }
+ else
+ {
+ /* Not a valid numeric inet address. */
+ /* Map host name to an address. */
+ if (!hp)
+ hp = gethostbyname(host);
+ if (!hp)
+ fatal("Bad host name: %.100s", host);
+ if (!hp->h_addr_list[0])
+ fatal("Host does not have an IP address: %.100s", host);
+
+ /* Loop through addresses for this host, and try each one in
+ sequence until the connection succeeds. */
+ for (i = 0; hp->h_addr_list[i]; i++)
+ {
+ /* Set the address to connect to. */
+ hostaddr->sin_family = hp->h_addrtype;
+ memcpy(&hostaddr->sin_addr, hp->h_addr_list[i],
+ sizeof(hostaddr->sin_addr));
+
+ debug("Connecting to %.200s [%.100s] port %d.",
+ host, inet_ntoa(hostaddr->sin_addr), port);
+
+ /* Create a socket for connecting. */
+ sock = ssh_create_socket(original_real_uid,
+ !anonymous && geteuid() == 0 &&
+ port < IPPORT_RESERVED);
+
+ /* Connect to the host. We use the user's uid in the hope that
+ it will help with tcp_wrappers showing the remote uid as
+ root. */
+ temporarily_use_uid(original_real_uid);
+ if (connect(sock, (struct sockaddr *)hostaddr,
+ sizeof(*hostaddr)) >= 0)
+ {
+ /* Successful connection. */
+ restore_uid();
+ break;
+ }
+ debug("connect: %.100s", strerror(errno));
+ restore_uid();
+
+ /* Close the failed socket; there appear to be some problems
+ when reusing a socket for which connect() has already
+ returned an error. */
+ shutdown(sock, SHUT_RDWR);
+ close(sock);
+ }
+ if (hp->h_addr_list[i])
+ break; /* Successful connection. */
+ }
+
+ /* Sleep a moment before retrying. */
+ sleep(1);
+ }
+ /* Return failure if we didn't get a successful connection. */
+ if (attempt >= connection_attempts)
+ return 0;
+
+ debug("Connection established.");
+
+ /* Set socket options. We would like the socket to disappear as soon as
+ it has been closed for whatever reason. */
+ /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
+ setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *)&on, sizeof(on));
+ linger.l_onoff = 1;
+ linger.l_linger = 5;
+ setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
+
+ /* Set the connection. */
+ packet_set_connection(sock, sock);
+
+ 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, bits;
+ 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, &bits, e, n, &comment);
+ status;
+ status = ssh_get_next_identity(auth, &bits, 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, bits, 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);
+ assert(len <= sizeof(buf) && 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,
+ int may_ask_passphrase)
+{
+ 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];
+ /* Request passphrase from the user. We read from /dev/tty to make
+ this work even if stdin has been redirected. If running in
+ batch mode, we just use the empty passphrase, which will fail and
+ return. */
+ snprintf(buf, sizeof buf,
+ "Enter passphrase for RSA key '%.100s': ", comment);
+ if (may_ask_passphrase)
+ 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; /* Server refuses to authenticate us with this method. */
+ }
+
+ /* 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));
+
+ /* 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);
+ }
+ return 0;
+}
+#endif /* KRB4 */
+
+#ifdef AFS
+int send_kerberos_tgt()
+{
+ CREDENTIALS *creds;
+ char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];
+ int r, type, plen;
+ unsigned char buffer[8192];
+ struct stat st;
+
+ /* Don't do anything if we don't have any tickets. */
+ if (stat(tkt_string(), &st) < 0) return 0;
+
+ creds = xmalloc(sizeof(*creds));
+
+ if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) {
+ debug("Kerberos V4 tf_fullname failed: %s",krb_err_txt[r]);
+ return 0;
+ }
+ if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) {
+ debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]);
+ return 0;
+ }
+ if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {
+ debug("Kerberos V4 ticket expired: %s", TKT_FILE);
+ return 0;
+ }
+
+ creds_to_radix(creds, buffer);
+ xfree(creds);
+
+ packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
+ packet_put_string((char *)buffer, strlen(buffer));
+ packet_send();
+ packet_write_wait();
+
+ type = packet_read(&plen);
+
+ if (type == SSH_SMSG_FAILURE)
+ debug("Kerberos TGT for realm %s rejected.", prealm);
+ else if (type != SSH_SMSG_SUCCESS)
+ packet_disconnect("Protocol error on Kerberos TGT response: %d", type);
+
+ return 1;
+}
+
+void send_afs_tokens(void)
+{
+ CREDENTIALS creds;
+ struct ViceIoctl parms;
+ struct ClearToken ct;
+ int i, type, len, plen;
+ char buf[2048], *p, *server_cell;
+ unsigned char buffer[8192];
+
+ /* Move over ktc_GetToken, here's something leaner. */
+ for (i = 0; i < 100; i++) { /* just in case */
+ parms.in = (char *)&i;
+ parms.in_size = sizeof(i);
+ parms.out = buf;
+ parms.out_size = sizeof(buf);
+ if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) break;
+ p = buf;
+
+ /* Get secret token. */
+ memcpy(&creds.ticket_st.length, p, sizeof(unsigned int));
+ if (creds.ticket_st.length > MAX_KTXT_LEN) break;
+ p += sizeof(unsigned int);
+ memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);
+ p += creds.ticket_st.length;
+
+ /* Get clear token. */
+ memcpy(&len, p, sizeof(len));
+ if (len != sizeof(struct ClearToken)) break;
+ p += sizeof(len);
+ memcpy(&ct, p, len);
+ p += len;
+ p += sizeof(len); /* primary flag */
+ server_cell = p;
+
+ /* Flesh out our credentials. */
+ strlcpy(creds.service, "afs", sizeof creds.service);
+ creds.instance[0] = '\0';
+ strlcpy(creds.realm, server_cell, REALM_SZ);
+ memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);
+ creds.issue_date = ct.BeginTimestamp;
+ creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp);
+ creds.kvno = ct.AuthHandle;
+ snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId);
+ creds.pinst[0] = '\0';
+
+ /* Encode token, ship it off. */
+ if (!creds_to_radix(&creds, buffer)) break;
+ packet_start(SSH_CMSG_HAVE_AFS_TOKEN);
+ packet_put_string((char *)buffer, strlen(buffer));
+ packet_send();
+ packet_write_wait();
+
+ /* Roger, Roger. Clearance, Clarence. What's your vector, Victor? */
+ type = packet_read(&plen);
+
+ if (type == SSH_SMSG_FAILURE)
+ debug("AFS token for cell %s rejected.", server_cell);
+ else if (type != SSH_SMSG_SUCCESS)
+ packet_disconnect("Protocol error on AFS token response: %d", type);
+ }
+}
+#endif /* AFS */
+
+/* Waits for the server identification string, and sends our own identification
+ string. */
+
+void ssh_exchange_identification()
+{
+ char buf[256], remote_version[256]; /* must be same size! */
+ int remote_major, remote_minor, i;
+ int connection_in = packet_get_connection_in();
+ int connection_out = packet_get_connection_out();
+ extern Options options;
+
+ /* Read other side\'s version identification. */
+ for (i = 0; i < sizeof(buf) - 1; i++)
+ {
+ if (read(connection_in, &buf[i], 1) != 1)
+ fatal("read: %.100s", strerror(errno));
+ if (buf[i] == '\r')
+ {
+ buf[i] = '\n';
+ buf[i + 1] = 0;
+ break;
+ }
+ if (buf[i] == '\n')
+ {
+ buf[i + 1] = 0;
+ break;
+ }
+ }
+ buf[sizeof(buf) - 1] = 0;
+
+ /* Check that the versions match. In future this might accept several
+ versions and set appropriate flags to handle them. */
+ if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
+ remote_version) != 3)
+ fatal("Bad remote protocol version identification: '%.100s'", buf);
+ debug("Remote protocol version %d.%d, remote software version %.100s",
+ remote_major, remote_minor, remote_version);
+
+ /* Check if the remote protocol version is too old. */
+ if (remote_major == 1 && remote_minor < 3)
+ fatal("Remote machine has too old SSH software version.");
+
+ /* We speak 1.3, too. */
+ if (remote_major == 1 && remote_minor == 3) {
+ enable_compat13();
+ if (options.forward_agent && strcmp(remote_version, SSH_VERSION) != 0) {
+ log("Agent forwarding disabled, remote version '%s' is not compatible.",
+ remote_version);
+ options.forward_agent = 0;
+ }
+ }
+#if 0
+ /* Removed for now, to permit compatibility with latter versions. The server
+ will reject our version and disconnect if it doesn't support it. */
+ if (remote_major != PROTOCOL_MAJOR)
+ fatal("Protocol major versions differ: %d vs. %d",
+ PROTOCOL_MAJOR, remote_major);
+#endif
+
+ /* Send our own protocol version identification. */
+ snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
+ PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
+ if (write(connection_out, buf, strlen(buf)) != strlen(buf))
+ fatal("write: %.100s", strerror(errno));
+}
+
+int ssh_cipher_default = SSH_CIPHER_3DES;
+
+int read_yes_or_no(const char *prompt, int defval)
+{
+ char buf[1024];
+ FILE *f;
+ int retval = -1;
+
+ if (isatty(0))
+ f = stdin;
+ else
+ f = fopen("/dev/tty", "rw");
+
+ if (f == NULL)
+ return 0;
+
+ fflush(stdout);
+
+ while (1)
+ {
+ fprintf(stderr, "%s", prompt);
+ if (fgets(buf, sizeof(buf), f) == NULL)
+ {
+ /* Print a newline (the prompt probably didn\'t have one). */
+ fprintf(stderr, "\n");
+ strlcpy(buf, "no", sizeof buf);
+ }
+ /* Remove newline from response. */
+ if (strchr(buf, '\n'))
+ *strchr(buf, '\n') = 0;
+
+ if (buf[0] == 0)
+ retval = defval;
+ if (strcmp(buf, "yes") == 0)
+ retval = 1;
+ if (strcmp(buf, "no") == 0)
+ retval = 0;
+
+ if (retval != -1)
+ {
+ if (f != stdin)
+ fclose(f);
+ return retval;
+ }
+ }
+}
+
+/* Starts a dialog with the server, and authenticates the current user on the
+ server. This does not need any extra privileges. The basic connection
+ to the server must already have been established before this is called.
+ User is the remote user; if it is NULL, the current local user name will
+ be used. Anonymous indicates that no rhosts authentication will be used.
+ If login fails, this function prints an error and never returns.
+ This function does not require super-user privileges. */
+
+void ssh_login(int host_key_valid,
+ RSA *own_host_key,
+ const char *orighost,
+ struct sockaddr_in *hostaddr,
+ Options *options, uid_t original_real_uid)
+{
+ int i, type;
+ char *password;
+ struct passwd *pw;
+ BIGNUM *key;
+ RSA *host_key, *file_key;
+ RSA *public_key;
+ unsigned char session_key[SSH_SESSION_KEY_LENGTH];
+ const char *server_user, *local_user;
+ char *cp, *host, *ip = NULL;
+ unsigned char check_bytes[8];
+ unsigned int supported_ciphers, supported_authentications, protocol_flags;
+ HostStatus host_status;
+ HostStatus ip_status;
+ int host_ip_differ = 0;
+ int local = (ntohl(hostaddr->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+ int payload_len, clen, sum_len = 0;
+ u_int32_t rand = 0;
+
+ if (options->check_host_ip)
+ ip = xstrdup(inet_ntoa(hostaddr->sin_addr));
+
+ /* Convert the user-supplied hostname into all lowercase. */
+ host = xstrdup(orighost);
+ for (cp = host; *cp; cp++)
+ if (isupper(*cp))
+ *cp = tolower(*cp);
+
+ /* Exchange protocol version identification strings with the server. */
+ ssh_exchange_identification();
+
+ /* Put the connection into non-blocking mode. */
+ packet_set_nonblocking();
+
+ /* Get local user name. Use it as server user if no user name
+ was given. */
+ pw = getpwuid(original_real_uid);
+ if (!pw)
+ fatal("User id %d not found from user database.", original_real_uid);
+ local_user = xstrdup(pw->pw_name);
+ server_user = options->user ? options->user : local_user;
+
+ debug("Waiting for server public key.");
+
+ /* Wait for a public key packet from the server. */
+ packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY);
+
+ /* Get check bytes from the packet. */
+ for (i = 0; i < 8; i++)
+ check_bytes[i] = packet_get_char();
+
+ /* Get the public key. */
+ public_key = RSA_new();
+ packet_get_int(); /* bits */
+ public_key->e = BN_new();
+ packet_get_bignum(public_key->e, &clen);
+ sum_len += clen;
+ public_key->n = BN_new();
+ packet_get_bignum(public_key->n, &clen);
+ sum_len += clen;
+
+ /* Get the host key. */
+ host_key = RSA_new();
+ packet_get_int(); /* bits */
+ host_key->e = BN_new();
+ packet_get_bignum(host_key->e, &clen);
+ sum_len += clen;
+ host_key->n = BN_new();
+ packet_get_bignum(host_key->n, &clen);
+ sum_len += clen;
+
+ /* Store the host key from the known host file in here
+ * so that we can compare it with the key for the IP
+ * address. */
+ file_key = RSA_new();
+ file_key->n = BN_new();
+ file_key->e = BN_new();
+
+ /* Get protocol flags. */
+ protocol_flags = packet_get_int();
+ packet_set_protocol_flags(protocol_flags);
+
+ /* Get supported cipher types. */
+ supported_ciphers = packet_get_int();
+
+ /* Get supported authentication types. */
+ supported_authentications = packet_get_int();
+
+ debug("Received server public key (%d bits) and host key (%d bits).",
+ BN_num_bits(public_key->n), BN_num_bits(host_key->n));
+
+ packet_integrity_check(payload_len,
+ 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4,
+ SSH_SMSG_PUBLIC_KEY);
+
+ /* Compute the session id. */
+ compute_session_id(session_id, check_bytes,
+ BN_num_bits(host_key->n), host_key->n,
+ BN_num_bits(public_key->n), public_key->n);
+
+ /* Check if the host key is present in the user\'s list of known hosts
+ or in the systemwide list. */
+ host_status = check_host_in_hostfile(options->user_hostfile,
+ host, BN_num_bits(host_key->n),
+ host_key->e, host_key->n,
+ file_key->e, file_key->n);
+ if (host_status == HOST_NEW)
+ host_status = check_host_in_hostfile(options->system_hostfile, host,
+ BN_num_bits(host_key->n),
+ host_key->e, host_key->n,
+ file_key->e, file_key->n);
+ /* Force accepting of the host key for localhost and 127.0.0.1.
+ The problem is that if the home directory is NFS-mounted to multiple
+ machines, localhost will refer to a different machine in each of them,
+ and the user will get bogus HOST_CHANGED warnings. This essentially
+ disables host authentication for localhost; however, this is probably
+ not a real problem. */
+ if (local) {
+ debug("Forcing accepting of host key for localhost.");
+ host_status = HOST_OK;
+ }
+
+ /* Also perform check for the ip address, skip the check if we are
+ localhost or the hostname was an ip address to begin with */
+ if (options->check_host_ip && !local && strcmp(host, ip)) {
+ RSA *ip_key = RSA_new();
+ ip_key->n = BN_new();
+ ip_key->e = BN_new();
+ ip_status = check_host_in_hostfile(options->user_hostfile, ip,
+ BN_num_bits(host_key->n),
+ host_key->e, host_key->n,
+ ip_key->e, ip_key->n);
+
+ if (ip_status == HOST_NEW)
+ ip_status = check_host_in_hostfile(options->system_hostfile, ip,
+ BN_num_bits(host_key->n),
+ host_key->e, host_key->n,
+ ip_key->e, ip_key->n);
+ if (host_status == HOST_CHANGED &&
+ (ip_status != HOST_CHANGED ||
+ (BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n))))
+ host_ip_differ = 1;
+
+ RSA_free(ip_key);
+ } else
+ ip_status = host_status;
+
+ RSA_free(file_key);
+
+ switch (host_status) {
+ case HOST_OK:
+ /* The host is known and the key matches. */
+ debug("Host '%.200s' is known and matches the host key.", host);
+ if (options->check_host_ip) {
+ if (ip_status == HOST_NEW) {
+ if (!add_host_to_hostfile(options->user_hostfile, ip,
+ BN_num_bits(host_key->n),
+ host_key->e, host_key->n))
+ log("Failed to add the host ip to the list of known hosts (%.30s).",
+ options->user_hostfile);
+ else
+ log("Warning: Permanently added host ip '%.30s' to the list of known hosts.", ip);
+ } else if (ip_status != HOST_OK)
+ log("Warning: the host key differ from the key of the ip address '%.30s' differs", ip);
+ }
+
+ break;
+ case HOST_NEW:
+ {
+ char hostline[1000], *hostp = hostline;
+ /* The host is new. */
+ if (options->strict_host_key_checking == 1) {
+ /* User has requested strict host key checking. We will not
+ add the host key automatically. The only alternative left
+ is to abort. */
+ fatal("No host key is known for %.200s and you have requested strict checking.", host);
+ } else if (options->strict_host_key_checking == 2) { /* The default */
+ char prompt[1024];
+ snprintf(prompt, sizeof(prompt),
+ "The authenticity of host '%.200s' can't be established.\n"
+ "Are you sure you want to continue connecting (yes/no)? ",
+ host);
+ if (!read_yes_or_no(prompt, -1))
+ fatal("Aborted by user!\n");
+ }
+
+ if (options->check_host_ip && ip_status == HOST_NEW && strcmp(host, ip))
+ snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
+ else
+ hostp = host;
+
+ /* If not in strict mode, add the key automatically to the local
+ known_hosts file. */
+ if (!add_host_to_hostfile(options->user_hostfile, hostp,
+ BN_num_bits(host_key->n),
+ host_key->e, host_key->n))
+ log("Failed to add the host to the list of known hosts (%.500s).",
+ options->user_hostfile);
+ else
+ log("Warning: Permanently added '%.200s' to the list of known hosts.",
+ hostp);
+ break;
+ }
+ case HOST_CHANGED:
+ if (options->check_host_ip) {
+ if (host_ip_differ) {
+ error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
+ error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
+ error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
+ error("The host key for %s has changed,", host);
+ error("but the key for the according IP address %s has", ip);
+ error("a different status. This could either mean that DNS");
+ error("SPOOFING is happening or the IP address for the host");
+ error("and its host key have changed at the same time");
+ }
+ }
+
+ /* The host key has changed. */
+ error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
+ error("@ WARNING: HOST IDENTIFICATION HAS CHANGED! @");
+ error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
+ error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
+ error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
+ error("It is also possible that the host key has just been changed.");
+ error("Please contact your system administrator.");
+ error("Add correct host key in %.100s to get rid of this message.",
+ options->user_hostfile);
+
+ /* If strict host key checking is in use, the user will have to edit
+ the key manually and we can only abort. */
+ if (options->strict_host_key_checking)
+ fatal("Host key for %.200s has changed and you have requested strict checking.", host);
+
+ /* If strict host key checking has not been requested, allow the
+ connection but without password authentication or
+ agent forwarding. */
+ if (options->password_authentication) {
+ error("Password authentication is disabled to avoid trojan horses.");
+ options->password_authentication = 0;
+ }
+ if (options->forward_agent) {
+ error("Agent forwarding is disabled to avoid trojan horses.");
+ options->forward_agent = 0;
+ }
+ /* XXX Should permit the user to change to use the new id. This could
+ be done by converting the host key to an identifying sentence, tell
+ that the host identifies itself by that sentence, and ask the user
+ if he/she whishes to accept the authentication. */
+ break;
+ }
+
+ if (options->check_host_ip)
+ xfree(ip);
+
+ /* Generate a session key. */
+ arc4random_stir();
+
+ /* Generate an encryption key for the session. The key is a 256 bit
+ random number, interpreted as a 32-byte key, with the least significant
+ 8 bits being the first byte of the key. */
+ for (i = 0; i < 32; i++) {
+ if (i % 4 == 0)
+ rand = arc4random();
+ session_key[i] = rand & 0xff;
+ rand >>= 8;
+ }
+
+ /* According to the protocol spec, the first byte of the session key is
+ the highest byte of the integer. The session key is xored with the
+ first 16 bytes of the session id. */
+ key = BN_new();
+ BN_set_word(key, 0);
+ for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++)
+ {
+ BN_lshift(key, key, 8);
+ if (i < 16)
+ BN_add_word(key, session_key[i] ^ session_id[i]);
+ else
+ BN_add_word(key, session_key[i]);
+ }
+
+ /* Encrypt the integer using the public key and host key of the server
+ (key with smaller modulus first). */
+ if (BN_cmp(public_key->n, host_key->n) < 0)
+ {
+ /* Public key has smaller modulus. */
+ assert(BN_num_bits(host_key->n) >=
+ BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED);
+
+ rsa_public_encrypt(key, key, public_key);
+ rsa_public_encrypt(key, key, host_key);
+ }
+ else
+ {
+ /* Host key has smaller modulus (or they are equal). */
+ assert(BN_num_bits(public_key->n) >=
+ BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED);
+
+ rsa_public_encrypt(key, key, host_key);
+ rsa_public_encrypt(key, key, public_key);
+ }
+
+ if (options->cipher == SSH_CIPHER_NOT_SET) {
+ if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default))
+ options->cipher = ssh_cipher_default;
+ else {
+ debug("Cipher %d not supported, using %.100s instead.",
+ cipher_name(ssh_cipher_default),
+ cipher_name(SSH_FALLBACK_CIPHER));
+ options->cipher = SSH_FALLBACK_CIPHER;
+ }
+ }
+
+ /* Check that the selected cipher is supported. */
+ if (!(supported_ciphers & (1 << options->cipher)))
+ fatal("Selected cipher type %.100s not supported by server.",
+ cipher_name(options->cipher));
+
+ debug("Encryption type: %.100s", cipher_name(options->cipher));
+
+ /* Send the encrypted session key to the server. */
+ packet_start(SSH_CMSG_SESSION_KEY);
+ packet_put_char(options->cipher);
+
+ /* Send the check bytes back to the server. */
+ for (i = 0; i < 8; i++)
+ packet_put_char(check_bytes[i]);
+
+ /* Send the encrypted encryption key. */
+ packet_put_bignum(key);
+
+ /* Send protocol flags. */
+ packet_put_int(SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
+
+ /* Send the packet now. */
+ packet_send();
+ packet_write_wait();
+
+ /* Destroy the session key integer and the public keys since we no longer
+ need them. */
+ BN_clear_free(key);
+ RSA_free(public_key);
+ RSA_free(host_key);
+
+ debug("Sent encrypted session key.");
+
+ /* Set the encryption key. */
+ packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH,
+ options->cipher, 1);
+
+ /* We will no longer need the session key here. Destroy any extra copies. */
+ memset(session_key, 0, sizeof(session_key));
+
+ /* Expect a success message from the server. Note that this message will
+ be received in encrypted form. */
+ packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
+
+ debug("Received encrypted confirmation.");
+
+ /* Send the name of the user to log in as on the server. */
+ packet_start(SSH_CMSG_USER);
+ packet_put_string(server_user, strlen(server_user));
+ packet_send();
+ packet_write_wait();
+
+ /* The server should respond with success if no authentication is needed
+ (the user has no password). Otherwise the server responds with
+ failure. */
+ type = packet_read(&payload_len);
+ if (type == SSH_SMSG_SUCCESS)
+ return; /* Connection was accepted without authentication. */
+ if (type != SSH_SMSG_FAILURE)
+ packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER",
+ type);
+
+#ifdef AFS
+ /* Try Kerberos tgt passing if the server supports it. */
+ if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
+ options->kerberos_tgt_passing)
+ {
+ if (options->cipher == SSH_CIPHER_NONE)
+ log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
+ (void)send_kerberos_tgt();
+ }
+
+ /* Try AFS token passing if the server supports it. */
+ if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&
+ options->afs_token_passing && k_hasafs()) {
+ if (options->cipher == SSH_CIPHER_NONE)
+ log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");
+ send_afs_tokens();
+ }
+#endif /* AFS */
+
+#ifdef KRB4
+ if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
+ options->kerberos_authentication)
+ {
+ debug("Trying Kerberos authentication.");
+ if (try_kerberos_authentication()) {
+ /* The server should respond with success or failure. */
+ type = packet_read(&payload_len);
+ if (type == SSH_SMSG_SUCCESS)
+ return; /* Successful connection. */
+ if (type != SSH_SMSG_FAILURE)
+ packet_disconnect("Protocol error: got %d in response to Kerberos auth", type);
+ }
+ }
+#endif /* KRB4 */
+
+ /* Use rhosts authentication if running in privileged socket and we do not
+ wish to remain anonymous. */
+ if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) &&
+ options->rhosts_authentication)
+ {
+ debug("Trying rhosts authentication.");
+ packet_start(SSH_CMSG_AUTH_RHOSTS);
+ packet_put_string(local_user, strlen(local_user));
+ packet_send();
+ packet_write_wait();
+
+ /* The server should respond with success or failure. */
+ type = packet_read(&payload_len);
+ if (type == SSH_SMSG_SUCCESS)
+ return; /* Successful connection. */
+ if (type != SSH_SMSG_FAILURE)
+ packet_disconnect("Protocol error: got %d in response to rhosts auth",
+ type);
+ }
+
+ /* Try .rhosts or /etc/hosts.equiv authentication with RSA host
+ authentication. */
+ if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&
+ options->rhosts_rsa_authentication && host_key_valid)
+ {
+ if (try_rhosts_rsa_authentication(local_user, own_host_key))
+ return; /* Successful authentication. */
+ }
+
+ /* Try RSA authentication if the server supports it. */
+ if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&
+ options->rsa_authentication)
+ {
+ /* Try RSA authentication using the authentication agent. The agent
+ is tried first because no passphrase is needed for it, whereas
+ identity files may require passphrases. */
+ if (try_agent_authentication())
+ return; /* Successful connection. */
+
+ /* Try RSA authentication for each identity. */
+ for (i = 0; i < options->num_identity_files; i++)
+ if (try_rsa_authentication(pw, options->identity_files[i],
+ !options->batch_mode))
+ return; /* Successful connection. */
+ }
+
+ /* Try password authentication if the server supports it. */
+ if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&
+ options->password_authentication && !options->batch_mode)
+ {
+ char prompt[80];
+ snprintf(prompt, sizeof(prompt), "%.30s@%.30s's password: ",
+ server_user, host);
+ debug("Doing password authentication.");
+ if (options->cipher == SSH_CIPHER_NONE)
+ log("WARNING: Encryption is disabled! Password will be transmitted in clear text.");
+ for (i = 0; i < options->number_of_password_prompts; i++) {
+ if (i != 0)
+ error("Permission denied, please try again.");
+ password = read_passphrase(prompt, 0);
+ packet_start(SSH_CMSG_AUTH_PASSWORD);
+ packet_put_string(password, strlen(password));
+ memset(password, 0, strlen(password));
+ xfree(password);
+ packet_send();
+ packet_write_wait();
+
+ type = packet_read(&payload_len);
+ if (type == SSH_SMSG_SUCCESS)
+ return; /* Successful connection. */
+ if (type != SSH_SMSG_FAILURE)
+ packet_disconnect("Protocol error: got %d in response to passwd auth", type);
+ }
+ }
+
+ /* All authentication methods have failed. Exit with an error message. */
+ fatal("Permission denied.");
+ /*NOTREACHED*/
+}