/*
-
-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.
-
-*/
+ * 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("$Id$");
+#ifdef HAVE_OPENSSL
#include <openssl/bn.h>
+#include <openssl/md5.h>
+#endif
+#ifdef HAVE_SSL
+#include <ssl/bn.h>
+#include <ssl/md5.h>
+#endif
+
#include "xmalloc.h"
#include "rsa.h"
#include "ssh.h"
#include "mpaux.h"
#include "uidswap.h"
#include "compat.h"
-
-#include <openssl/md5.h>
+#include "readconf.h"
+#include "fingerprint.h"
/* Session id for the current session. */
unsigned char session_id[16];
-/* Connect to the given ssh server using a proxy command. */
+extern Options options;
+extern char *__progname;
+/*
+ * Connect to the given ssh server using a proxy command.
+ */
int
-ssh_proxy_connect(const char *host, int port, uid_t original_real_uid,
+ssh_proxy_connect(const char *host, u_short 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 command;
+ const char *cp;
+ char *command_string;
+ int pin[2], pout[2];
+ int pid;
+ char strport[NI_MAXSERV];
+
+ /* Convert the port number into a string. */
+ snprintf(strport, sizeof strport, "%hu", 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, strport, strlen(strport));
+ cp++;
+ continue;
+ }
+ buffer_append(&command, cp, 1);
}
- 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]);
+ 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");
+ /* Cannot be 1 because pin allocated two descriptors. */
+ close(pout[1]);
+
+ /* 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);
}
- 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;
-}
+ /* 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);
-/* Creates a (possibly privileged) socket for use as the ssh connection. */
+ /* Set the connection file descriptors. */
+ packet_set_connection(pout[0], pin[1]);
-int ssh_create_socket(uid_t original_real_uid, int privileged)
+ 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 family)
{
- 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;
+ 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_af(&p, family);
+ if (sock < 0)
+ fatal("rresvport: af=%d %.100s", family, 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(family, SOCK_STREAM, 0);
+ if (sock < 0)
+ error("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)
+/*
+ * Opens a TCP/IP connection to the remote server on the given host.
+ * The address of the remote host will be returned in hostaddr.
+ * 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_storage * hostaddr,
+ u_short 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);
+ int sock = -1, attempt;
+ struct servent *sp;
+ struct addrinfo hints, *ai, *aitop;
+ char ntop[NI_MAXHOST], strport[NI_MAXSERV];
+ int gaierr;
+ 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;
}
- 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;
+ /* 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. */
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = IPv4or6;
+ hints.ai_socktype = SOCK_STREAM;
+ snprintf(strport, sizeof strport, "%d", port);
+ if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
+ fatal("%s: %.100s: %s", __progname, host,
+ gai_strerror(gaierr));
+
+ /*
+ * 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...");
+
+ /* Loop through addresses for this host, and try each one in
+ sequence until the connection succeeds. */
+ for (ai = aitop; ai; ai = ai->ai_next) {
+ if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
+ continue;
+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
+ ntop, sizeof(ntop), strport, sizeof(strport),
+ NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
+ error("ssh_connect: getnameinfo failed");
+ continue;
+ }
+ debug("Connecting to %.200s [%.100s] port %s.",
+ host, ntop, strport);
+
+ /* Create a socket for connecting. */
+ sock = ssh_create_socket(original_real_uid,
+ !anonymous && geteuid() == 0 && port < IPPORT_RESERVED,
+ ai->ai_family);
+ if (sock < 0)
+ continue;
+
+ /* 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, ai->ai_addr, ai->ai_addrlen) >= 0) {
+ /* Successful connection. */
+ memcpy(hostaddr, ai->ai_addr, sizeof(*(ai->ai_addr)));
+ restore_uid();
+ break;
+ } else {
+ 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);
+ }
}
- 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. */
+ if (ai)
+ break; /* Successful connection. */
+
+ /* Sleep a moment before retrying. */
+ sleep(1);
}
- /* Sleep a moment before retrying. */
- sleep(1);
- }
- /* Return failure if we didn't get a successful connection. */
- if (attempt >= connection_attempts)
- return 0;
+ freeaddrinfo(aitop);
- debug("Connection established.");
+ /* Return failure if we didn't get a successful connection. */
+ if (attempt >= connection_attempts)
+ return 0;
- /* 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));
+ debug("Connection established.");
- /* Set the connection. */
- packet_set_connection(sock, sock);
+ /*
+ * 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)); */
+ linger.l_onoff = 1;
+ linger.l_linger = 5;
+ setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
- return 1;
-}
+ /* Set the connection. */
+ packet_set_connection(sock, sock);
-/* Checks if the user has an authentication agent, and if so, tries to
- authenticate using the agent. */
+ 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;
- }
+ 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);
- /* Otherwise it should return failure. */
- if (type != SSH_SMSG_FAILURE)
- packet_disconnect("Protocol error waiting RSA auth response: %d",
- type);
- }
+ packet_get_bignum(challenge, &clen);
- BN_clear_free(e);
- BN_clear_free(n);
- BN_clear_free(challenge);
+ packet_integrity_check(plen, clen, type);
- debug("RSA authentication using agent refused.");
- return 0;
-}
+ 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);
-/* Computes the proper response to a RSA challenge, and sends the response to
- the server. */
+ 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)
+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));
-}
+ 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();
-/* Checks if the user has authentication file, and if so, tries to authenticate
- the user using it. */
+ 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)
+try_rsa_authentication(const char *authfile)
{
- 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("");
+ 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);
+ /* Could not load it. Fail. */
+ return 0;
}
-
- /* 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;
+ 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;
+ }
+ /* 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);
- /* 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;
-}
+ /* Compute and send a response to the challenge. */
+ respond_to_rsa_challenge(challenge, private_key);
-/* Tries to authenticate the user using combined rhosts or /etc/hosts.equiv
- authentication and RSA host authentication. */
+ /* 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)
+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;
+ 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()
+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;
+ 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);
+ }
+ return 0;
}
+
#endif /* KRB4 */
#ifdef AFS
-int send_kerberos_tgt()
+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;
+ 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)
+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);
- }
+ 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. */
+/*
+ * Tries to authenticate with any string-based challenge/response system.
+ * Note that the client code is not tied to s/key or TIS.
+ */
+int
+try_skey_authentication()
+{
+ int type, i, payload_len;
+ char *challenge, *response;
+
+ debug("Doing skey authentication.");
+
+ /* request a challenge */
+ packet_start(SSH_CMSG_AUTH_TIS);
+ packet_send();
+ packet_write_wait();
+
+ type = packet_read(&payload_len);
+ if (type != SSH_SMSG_FAILURE &&
+ type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
+ packet_disconnect("Protocol error: got %d in response "
+ "to skey-auth", type);
+ }
+ if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
+ debug("No challenge for skey authentication.");
+ return 0;
+ }
+ challenge = packet_get_string(&payload_len);
+ if (options.cipher == SSH_CIPHER_NONE)
+ log("WARNING: Encryption is disabled! "
+ "Reponse will be transmitted in clear text.");
+ fprintf(stderr, "%s\n", challenge);
+ fflush(stderr);
+ for (i = 0; i < options.number_of_password_prompts; i++) {
+ if (i != 0)
+ error("Permission denied, please try again.");
+ response = read_passphrase("Response: ", 0);
+ packet_start(SSH_CMSG_AUTH_TIS_RESPONSE);
+ packet_put_string(response, strlen(response));
+ memset(response, 0, strlen(response));
+ xfree(response);
+ packet_send();
+ packet_write_wait();
+ type = packet_read(&payload_len);
+ if (type == SSH_SMSG_SUCCESS)
+ return 1;
+ if (type != SSH_SMSG_FAILURE)
+ packet_disconnect("Protocol error: got %d in response "
+ "to skey-auth-reponse", type);
+ }
+ /* failure */
+ return 0;
+}
+
+/*
+ * Tries to authenticate with plain passwd authentication.
+ */
+int
+try_password_authentication(char *prompt)
+{
+ int type, i, payload_len;
+ char *password;
+
+ 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 1;
+ if (type != SSH_SMSG_FAILURE)
+ packet_disconnect("Protocol error: got %d in response to passwd auth", type);
+ }
+ /* failure */
+ return 0;
+}
-void ssh_exchange_identification()
+/*
+ * 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;
+ 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();
+
+ /* Read other side\'s version identification. */
+ for (i = 0; i < sizeof(buf) - 1; i++) {
+ if (read(connection_in, &buf[i], 1) != 1)
+ fatal("ssh_exchange_identification: 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;
+ }
}
- 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, "OpenSSH-1.1") != 0) {
+ log("Agent forwarding disabled, remote version '%s' is not compatible.",
+ remote_version);
+ options.forward_agent = 0;
+ }
}
- }
- 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);
+ /*
+ * 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));
+ /* Send our own protocol version identification. */
+ snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
+ PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
+ if (atomicio(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)
+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;
+ }
+ }
+}
+
+/*
+ * check whether the supplied host key is valid, return only if ok.
+ */
+
+void
+check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
{
- 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);
+ RSA *file_key;
+ char *ip = NULL;
+ char hostline[1000], *hostp;
+ HostStatus host_status;
+ HostStatus ip_status;
+ int local = 0, host_ip_differ = 0;
+ int salen;
+ char ntop[NI_MAXHOST];
+
+ /*
+ * Force accepting of the host key for loopback/localhost. 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.
+ */
+ switch (hostaddr->sa_family) {
+ case AF_INET:
+ local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+ salen = sizeof(struct sockaddr_in);
+ break;
+ case AF_INET6:
+ local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
+ salen = sizeof(struct sockaddr_in6);
+ break;
+ default:
+ local = 0;
+ salen = sizeof(struct sockaddr_storage);
+ break;
}
- /* 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;
+ if (local) {
+ debug("Forcing accepting of host key for loopback/localhost.");
+ return;
}
- }
+
+ /*
+ * Turn off check_host_ip for proxy connects, since
+ * we don't have the remote ip-address
+ */
+ if (options.proxy_command != NULL && options.check_host_ip)
+ options.check_host_ip = 0;
+
+ if (options.check_host_ip) {
+ if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
+ NULL, 0, NI_NUMERICHOST) != 0)
+ fatal("check_host_key: getnameinfo failed");
+ ip = xstrdup(ntop);
+ }
+
+ /*
+ * 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();
+
+ /*
+ * 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,
+ 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,
+ host_key->e, host_key->n,
+ file_key->e, file_key->n);
+ /*
+ * 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,
+ 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,
+ 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,
+ host_key->e, host_key->n))
+ log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).",
+ ip, options.user_hostfile);
+ else
+ log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.",
+ ip);
+ } else if (ip_status != HOST_OK)
+ log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'",
+ host, ip);
+ }
+ break;
+ case HOST_NEW:
+ /* 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];
+ char *fp = fingerprint(host_key->e, host_key->n);
+ snprintf(prompt, sizeof(prompt),
+ "The authenticity of host '%.200s' can't be established.\n"
+ "Key fingerprint is %d %s.\n"
+ "Are you sure you want to continue connecting (yes/no)? ",
+ host, BN_num_bits(host_key->n), fp);
+ 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);
+ hostp = hostline;
+ } 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,
+ 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 && host_ip_differ) {
+ char *msg;
+ if (ip_status == HOST_NEW)
+ msg = "is unknown";
+ else if (ip_status == HOST_OK)
+ msg = "is unchanged";
+ else
+ msg = "has a different value";
+ error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
+ error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
+ error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
+ error("The host key for %s has changed,", host);
+ error("and the key for the according IP address %s", ip);
+ error("%s. This could either mean that", msg);
+ error("DNS 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: REMOTE 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);
}
-/* 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)
+/*
+ * 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 *hostaddr,
+ 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);
+ int i, type;
+ struct passwd *pw;
+ BIGNUM *key;
+ RSA *host_key;
+ RSA *public_key;
+ int bits, rbits;
+ unsigned char session_key[SSH_SESSION_KEY_LENGTH];
+ const char *server_user, *local_user;
+ char *host, *cp;
+ unsigned char check_bytes[8];
+ unsigned int supported_ciphers, supported_authentications;
+ unsigned int server_flags, client_flags;
+ int payload_len, clen, sum_len = 0;
+ u_int32_t rand = 0;
+
+ /* 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();
+ bits = 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;
+
+ rbits = BN_num_bits(public_key->n);
+ if (bits != rbits) {
+ log("Warning: Server lies about size of server public key: "
+ "actual size is %d bits vs. announced %d.", rbits, bits);
+ log("Warning: This may be due to an old implementation of ssh.");
+ }
+ /* Get the host key. */
+ host_key = RSA_new();
+ bits = 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;
+
+ rbits = BN_num_bits(host_key->n);
+ if (bits != rbits) {
+ log("Warning: Server lies about size of server host key: "
+ "actual size is %d bits vs. announced %d.", rbits, bits);
+ log("Warning: This may be due to an old implementation of ssh.");
+ }
+
+ /* Get protocol flags. */
+ server_flags = packet_get_int();
+ packet_set_protocol_flags(server_flags);
+
+ supported_ciphers = packet_get_int();
+ 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);
+
+ check_host_key(host, hostaddr, host_key);
+
+ client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;
+
+ compute_session_id(session_id, check_bytes, host_key->n, public_key->n);
+
+ /* 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. */
+ if (BN_num_bits(host_key->n) <
+ BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) {
+ fatal("respond_to_rsa_challenge: host_key %d < public_key %d + "
+ "SSH_KEY_BITS_RESERVED %d",
+ 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). */
+ if (BN_num_bits(public_key->n) <
+ BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) {
+ fatal("respond_to_rsa_challenge: public_key %d < host_key %d + "
+ "SSH_KEY_BITS_RESERVED %d",
+ 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 %s 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(client_flags);
+
+ /* 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);
+
+ /* 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);
+
+ /* check whether the connection was accepted without authentication. */
if (type == SSH_SMSG_SUCCESS)
- return; /* Successful connection. */
+ return;
if (type != SSH_SMSG_FAILURE)
- packet_disconnect("Protocol error: got %d in response to passwd auth", type);
- }
- }
+ packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER",
+ type);
- /* All authentication methods have failed. Exit with an error message. */
- fatal("Permission denied.");
- /*NOTREACHED*/
+#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;
+ 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;
+ 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;
+ }
+ /* 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;
+
+ /* Try RSA authentication for each identity. */
+ for (i = 0; i < options.num_identity_files; i++)
+ if (try_rsa_authentication(options.identity_files[i]))
+ return;
+ }
+ /* Try skey authentication if the server supports it. */
+ if ((supported_authentications & (1 << SSH_AUTH_TIS)) &&
+ options.skey_authentication && !options.batch_mode) {
+ if (try_skey_authentication())
+ return;
+ }
+ /* 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@%.40s's password: ",
+ server_user, host);
+ if (try_password_authentication(prompt))
+ return;
+ }
+ /* All authentication methods have failed. Exit with an error message. */
+ fatal("Permission denied.");
+ /* NOTREACHED */
}
andersk / openssh.git / blobdiff