Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
| 5 | * Created: Sat Mar 18 22:15:47 1995 ylo |
| 6 | * Code to connect to a remote host, and to perform the client side of the |
| 7 | * login (authentication) dialog. |
| 8 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 9 | |
| 10 | #include "includes.h" |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 11 | RCSID("$OpenBSD: sshconnect.c,v 1.72 2000/05/04 09:50:22 markus Exp $"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 12 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 13 | #include <openssl/bn.h> |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 14 | #include <openssl/dsa.h> |
| 15 | #include <openssl/rsa.h> |
| 16 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 17 | #include "xmalloc.h" |
| 18 | #include "rsa.h" |
| 19 | #include "ssh.h" |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 20 | #include "buffer.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 21 | #include "packet.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 22 | #include "uidswap.h" |
| 23 | #include "compat.h" |
Damien Miller | 6d7b2cd | 1999-11-12 15:19:27 +1100 | [diff] [blame] | 24 | #include "readconf.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 25 | #include "key.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 26 | #include "sshconnect.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 27 | #include "hostfile.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 28 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 29 | char *client_version_string = NULL; |
| 30 | char *server_version_string = NULL; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 31 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 32 | extern Options options; |
Damien Miller | 70fb671 | 2000-05-01 20:59:50 +1000 | [diff] [blame] | 33 | #ifdef HAVE___PROGNAME |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 34 | extern char *__progname; |
Damien Miller | 70fb671 | 2000-05-01 20:59:50 +1000 | [diff] [blame] | 35 | #else /* HAVE___PROGNAME */ |
| 36 | static const char *__progname = "ssh"; |
| 37 | #endif /* HAVE___PROGNAME */ |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 38 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 39 | /* |
| 40 | * Connect to the given ssh server using a proxy command. |
| 41 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 42 | int |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 43 | ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid, |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 44 | const char *proxy_command) |
| 45 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 46 | Buffer command; |
| 47 | const char *cp; |
| 48 | char *command_string; |
| 49 | int pin[2], pout[2]; |
Damien Miller | 166fca8 | 2000-04-20 07:42:21 +1000 | [diff] [blame] | 50 | pid_t pid; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 51 | char strport[NI_MAXSERV]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 52 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 53 | /* Convert the port number into a string. */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 54 | snprintf(strport, sizeof strport, "%hu", port); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 55 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 56 | /* Build the final command string in the buffer by making the |
| 57 | appropriate substitutions to the given proxy command. */ |
| 58 | buffer_init(&command); |
| 59 | for (cp = proxy_command; *cp; cp++) { |
| 60 | if (cp[0] == '%' && cp[1] == '%') { |
| 61 | buffer_append(&command, "%", 1); |
| 62 | cp++; |
| 63 | continue; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 64 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 65 | if (cp[0] == '%' && cp[1] == 'h') { |
| 66 | buffer_append(&command, host, strlen(host)); |
| 67 | cp++; |
| 68 | continue; |
| 69 | } |
| 70 | if (cp[0] == '%' && cp[1] == 'p') { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 71 | buffer_append(&command, strport, strlen(strport)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 72 | cp++; |
| 73 | continue; |
| 74 | } |
| 75 | buffer_append(&command, cp, 1); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 76 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 77 | buffer_append(&command, "\0", 1); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 78 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 79 | /* Get the final command string. */ |
| 80 | command_string = buffer_ptr(&command); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 81 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 82 | /* Create pipes for communicating with the proxy. */ |
| 83 | if (pipe(pin) < 0 || pipe(pout) < 0) |
| 84 | fatal("Could not create pipes to communicate with the proxy: %.100s", |
| 85 | strerror(errno)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 86 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 87 | debug("Executing proxy command: %.500s", command_string); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 88 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 89 | /* Fork and execute the proxy command. */ |
| 90 | if ((pid = fork()) == 0) { |
| 91 | char *argv[10]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 92 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 93 | /* Child. Permanently give up superuser privileges. */ |
| 94 | permanently_set_uid(original_real_uid); |
| 95 | |
| 96 | /* Redirect stdin and stdout. */ |
| 97 | close(pin[1]); |
| 98 | if (pin[0] != 0) { |
| 99 | if (dup2(pin[0], 0) < 0) |
| 100 | perror("dup2 stdin"); |
| 101 | close(pin[0]); |
| 102 | } |
| 103 | close(pout[0]); |
| 104 | if (dup2(pout[1], 1) < 0) |
| 105 | perror("dup2 stdout"); |
| 106 | /* Cannot be 1 because pin allocated two descriptors. */ |
| 107 | close(pout[1]); |
| 108 | |
| 109 | /* Stderr is left as it is so that error messages get |
| 110 | printed on the user's terminal. */ |
| 111 | argv[0] = "/bin/sh"; |
| 112 | argv[1] = "-c"; |
| 113 | argv[2] = command_string; |
| 114 | argv[3] = NULL; |
| 115 | |
| 116 | /* Execute the proxy command. Note that we gave up any |
| 117 | extra privileges above. */ |
| 118 | execv("/bin/sh", argv); |
| 119 | perror("/bin/sh"); |
| 120 | exit(1); |
| 121 | } |
| 122 | /* Parent. */ |
| 123 | if (pid < 0) |
| 124 | fatal("fork failed: %.100s", strerror(errno)); |
| 125 | |
| 126 | /* Close child side of the descriptors. */ |
| 127 | close(pin[0]); |
| 128 | close(pout[1]); |
| 129 | |
| 130 | /* Free the command name. */ |
| 131 | buffer_free(&command); |
| 132 | |
| 133 | /* Set the connection file descriptors. */ |
| 134 | packet_set_connection(pout[0], pin[1]); |
| 135 | |
| 136 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 137 | } |
| 138 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 139 | /* |
| 140 | * Creates a (possibly privileged) socket for use as the ssh connection. |
| 141 | */ |
| 142 | int |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 143 | ssh_create_socket(uid_t original_real_uid, int privileged, int family) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 144 | { |
| 145 | int sock; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 146 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 147 | /* |
| 148 | * If we are running as root and want to connect to a privileged |
| 149 | * port, bind our own socket to a privileged port. |
| 150 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 151 | if (privileged) { |
| 152 | int p = IPPORT_RESERVED - 1; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 153 | sock = rresvport_af(&p, family); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 154 | if (sock < 0) |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 155 | error("rresvport: af=%d %.100s", family, strerror(errno)); |
| 156 | else |
| 157 | debug("Allocated local port %d.", p); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 158 | } else { |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 159 | /* |
| 160 | * Just create an ordinary socket on arbitrary port. We use |
| 161 | * the user's uid to create the socket. |
| 162 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 163 | temporarily_use_uid(original_real_uid); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 164 | sock = socket(family, SOCK_STREAM, 0); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 165 | if (sock < 0) |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 166 | error("socket: %.100s", strerror(errno)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 167 | restore_uid(); |
| 168 | } |
| 169 | return sock; |
| 170 | } |
| 171 | |
| 172 | /* |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 173 | * Opens a TCP/IP connection to the remote server on the given host. |
| 174 | * The address of the remote host will be returned in hostaddr. |
| 175 | * If port is 0, the default port will be used. If anonymous is zero, |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 176 | * a privileged port will be allocated to make the connection. |
| 177 | * This requires super-user privileges if anonymous is false. |
| 178 | * Connection_attempts specifies the maximum number of tries (one per |
| 179 | * second). If proxy_command is non-NULL, it specifies the command (with %h |
| 180 | * and %p substituted for host and port, respectively) to use to contact |
| 181 | * the daemon. |
| 182 | */ |
| 183 | int |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 184 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 185 | u_short port, int connection_attempts, |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 186 | int anonymous, uid_t original_real_uid, |
| 187 | const char *proxy_command) |
| 188 | { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 189 | int sock = -1, attempt; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 190 | struct servent *sp; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 191 | struct addrinfo hints, *ai, *aitop; |
| 192 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
| 193 | int gaierr; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 194 | struct linger linger; |
| 195 | |
| 196 | debug("ssh_connect: getuid %d geteuid %d anon %d", |
| 197 | (int) getuid(), (int) geteuid(), anonymous); |
| 198 | |
| 199 | /* Get default port if port has not been set. */ |
| 200 | if (port == 0) { |
| 201 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); |
| 202 | if (sp) |
| 203 | port = ntohs(sp->s_port); |
| 204 | else |
| 205 | port = SSH_DEFAULT_PORT; |
| 206 | } |
| 207 | /* If a proxy command is given, connect using it. */ |
| 208 | if (proxy_command != NULL) |
| 209 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); |
| 210 | |
| 211 | /* No proxy command. */ |
| 212 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 213 | memset(&hints, 0, sizeof(hints)); |
| 214 | hints.ai_family = IPv4or6; |
| 215 | hints.ai_socktype = SOCK_STREAM; |
| 216 | snprintf(strport, sizeof strport, "%d", port); |
| 217 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
| 218 | fatal("%s: %.100s: %s", __progname, host, |
| 219 | gai_strerror(gaierr)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 220 | |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 221 | /* |
| 222 | * Try to connect several times. On some machines, the first time |
| 223 | * will sometimes fail. In general socket code appears to behave |
| 224 | * quite magically on many machines. |
| 225 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 226 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
| 227 | if (attempt > 0) |
| 228 | debug("Trying again..."); |
| 229 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 230 | /* Loop through addresses for this host, and try each one in |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 231 | sequence until the connection succeeds. */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 232 | for (ai = aitop; ai; ai = ai->ai_next) { |
| 233 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) |
| 234 | continue; |
| 235 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, |
| 236 | ntop, sizeof(ntop), strport, sizeof(strport), |
| 237 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { |
| 238 | error("ssh_connect: getnameinfo failed"); |
| 239 | continue; |
| 240 | } |
| 241 | debug("Connecting to %.200s [%.100s] port %s.", |
| 242 | host, ntop, strport); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 243 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 244 | /* Create a socket for connecting. */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 245 | sock = ssh_create_socket(original_real_uid, |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 246 | !anonymous && geteuid() == 0 && port < IPPORT_RESERVED, |
| 247 | ai->ai_family); |
| 248 | if (sock < 0) |
| 249 | continue; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 250 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 251 | /* Connect to the host. We use the user's uid in the |
| 252 | * hope that it will help with tcp_wrappers showing |
| 253 | * the remote uid as root. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 254 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 255 | temporarily_use_uid(original_real_uid); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 256 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
| 257 | /* Successful connection. */ |
Damien Miller | 95fe91b | 2000-05-13 12:31:22 +1000 | [diff] [blame^] | 258 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 259 | restore_uid(); |
| 260 | break; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 261 | } else { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 262 | debug("connect: %.100s", strerror(errno)); |
| 263 | restore_uid(); |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 264 | /* |
| 265 | * Close the failed socket; there appear to |
| 266 | * be some problems when reusing a socket for |
| 267 | * which connect() has already returned an |
| 268 | * error. |
| 269 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 270 | shutdown(sock, SHUT_RDWR); |
| 271 | close(sock); |
| 272 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 273 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 274 | if (ai) |
| 275 | break; /* Successful connection. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 276 | |
| 277 | /* Sleep a moment before retrying. */ |
| 278 | sleep(1); |
| 279 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 280 | |
| 281 | freeaddrinfo(aitop); |
| 282 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 283 | /* Return failure if we didn't get a successful connection. */ |
| 284 | if (attempt >= connection_attempts) |
| 285 | return 0; |
| 286 | |
| 287 | debug("Connection established."); |
| 288 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 289 | /* |
| 290 | * Set socket options. We would like the socket to disappear as soon |
| 291 | * as it has been closed for whatever reason. |
| 292 | */ |
| 293 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 294 | linger.l_onoff = 1; |
| 295 | linger.l_linger = 5; |
| 296 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); |
| 297 | |
| 298 | /* Set the connection. */ |
| 299 | packet_set_connection(sock, sock); |
| 300 | |
| 301 | return 1; |
| 302 | } |
| 303 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 304 | char * |
| 305 | chop(char *s) |
| 306 | { |
| 307 | char *t = s; |
| 308 | while (*t) { |
| 309 | if(*t == '\n' || *t == '\r') { |
| 310 | *t = '\0'; |
| 311 | return s; |
| 312 | } |
| 313 | t++; |
| 314 | } |
| 315 | return s; |
| 316 | |
| 317 | } |
| 318 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 319 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 320 | * Waits for the server identification string, and sends our own |
| 321 | * identification string. |
| 322 | */ |
| 323 | void |
| 324 | ssh_exchange_identification() |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 325 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 326 | char buf[256], remote_version[256]; /* must be same size! */ |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 327 | int remote_major, remote_minor, i, mismatch; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 328 | int connection_in = packet_get_connection_in(); |
| 329 | int connection_out = packet_get_connection_out(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 330 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 331 | /* Read other side\'s version identification. */ |
| 332 | for (i = 0; i < sizeof(buf) - 1; i++) { |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 333 | int len = read(connection_in, &buf[i], 1); |
| 334 | if (len < 0) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 335 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 336 | if (len != 1) |
| 337 | fatal("ssh_exchange_identification: Connection closed by remote host"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 338 | if (buf[i] == '\r') { |
| 339 | buf[i] = '\n'; |
| 340 | buf[i + 1] = 0; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 341 | continue; /**XXX wait for \n */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 342 | } |
| 343 | if (buf[i] == '\n') { |
| 344 | buf[i + 1] = 0; |
| 345 | break; |
| 346 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 347 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 348 | buf[sizeof(buf) - 1] = 0; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 349 | server_version_string = xstrdup(buf); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 350 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 351 | /* |
| 352 | * Check that the versions match. In future this might accept |
| 353 | * several versions and set appropriate flags to handle them. |
| 354 | */ |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 355 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", |
| 356 | &remote_major, &remote_minor, remote_version) != 3) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 357 | fatal("Bad remote protocol version identification: '%.100s'", buf); |
| 358 | debug("Remote protocol version %d.%d, remote software version %.100s", |
| 359 | remote_major, remote_minor, remote_version); |
| 360 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 361 | compat_datafellows(remote_version); |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 362 | mismatch = 0; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 363 | |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 364 | switch(remote_major) { |
| 365 | case 1: |
| 366 | if (remote_minor == 99 && |
| 367 | (options.protocol & SSH_PROTO_2) && |
| 368 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { |
| 369 | enable_compat20(); |
| 370 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 371 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 372 | if (!(options.protocol & SSH_PROTO_1)) { |
| 373 | mismatch = 1; |
| 374 | break; |
| 375 | } |
| 376 | if (remote_minor < 3) { |
| 377 | fatal("Remote machine has too old SSH software version."); |
| 378 | } else if (remote_minor == 3) { |
| 379 | /* We speak 1.3, too. */ |
| 380 | enable_compat13(); |
| 381 | if (options.forward_agent) { |
| 382 | log("Agent forwarding disabled for protocol 1.3"); |
| 383 | options.forward_agent = 0; |
| 384 | } |
| 385 | } |
| 386 | break; |
| 387 | case 2: |
| 388 | if (options.protocol & SSH_PROTO_2) { |
| 389 | enable_compat20(); |
| 390 | break; |
| 391 | } |
| 392 | /* FALLTHROUGH */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 393 | default: |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 394 | mismatch = 1; |
| 395 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 396 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 397 | if (mismatch) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 398 | fatal("Protocol major versions differ: %d vs. %d", |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 399 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
| 400 | remote_major); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 401 | if (compat20) |
| 402 | packet_set_ssh2_format(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 403 | /* Send our own protocol version identification. */ |
| 404 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 405 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
| 406 | compat20 ? PROTOCOL_MINOR_2 : PROTOCOL_MINOR_1, |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 407 | SSH_VERSION); |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 408 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 409 | fatal("write: %.100s", strerror(errno)); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 410 | client_version_string = xstrdup(buf); |
| 411 | chop(client_version_string); |
| 412 | chop(server_version_string); |
| 413 | debug("Local version string %.100s", client_version_string); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 414 | } |
| 415 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 416 | int |
| 417 | read_yes_or_no(const char *prompt, int defval) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 418 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 419 | char buf[1024]; |
| 420 | FILE *f; |
| 421 | int retval = -1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 422 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 423 | if (isatty(0)) |
| 424 | f = stdin; |
| 425 | else |
| 426 | f = fopen("/dev/tty", "rw"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 427 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 428 | if (f == NULL) |
| 429 | return 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 430 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 431 | fflush(stdout); |
| 432 | |
| 433 | while (1) { |
| 434 | fprintf(stderr, "%s", prompt); |
| 435 | if (fgets(buf, sizeof(buf), f) == NULL) { |
| 436 | /* Print a newline (the prompt probably didn\'t have one). */ |
| 437 | fprintf(stderr, "\n"); |
| 438 | strlcpy(buf, "no", sizeof buf); |
| 439 | } |
| 440 | /* Remove newline from response. */ |
| 441 | if (strchr(buf, '\n')) |
| 442 | *strchr(buf, '\n') = 0; |
| 443 | |
| 444 | if (buf[0] == 0) |
| 445 | retval = defval; |
| 446 | if (strcmp(buf, "yes") == 0) |
| 447 | retval = 1; |
| 448 | if (strcmp(buf, "no") == 0) |
| 449 | retval = 0; |
| 450 | |
| 451 | if (retval != -1) { |
| 452 | if (f != stdin) |
| 453 | fclose(f); |
| 454 | return retval; |
| 455 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 456 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 457 | } |
| 458 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 459 | /* |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 460 | * check whether the supplied host key is valid, return only if ok. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 461 | */ |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 462 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 463 | void |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 464 | check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key, |
| 465 | const char *user_hostfile, const char *system_hostfile) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 466 | { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 467 | Key *file_key; |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 468 | char *type = key_type(host_key); |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 469 | char *ip = NULL; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 470 | char hostline[1000], *hostp; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 471 | HostStatus host_status; |
| 472 | HostStatus ip_status; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 473 | int local = 0, host_ip_differ = 0; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 474 | int salen; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 475 | char ntop[NI_MAXHOST]; |
| 476 | |
| 477 | /* |
| 478 | * Force accepting of the host key for loopback/localhost. The |
| 479 | * problem is that if the home directory is NFS-mounted to multiple |
| 480 | * machines, localhost will refer to a different machine in each of |
| 481 | * them, and the user will get bogus HOST_CHANGED warnings. This |
| 482 | * essentially disables host authentication for localhost; however, |
| 483 | * this is probably not a real problem. |
| 484 | */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 485 | /** hostaddr == 0! */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 486 | switch (hostaddr->sa_family) { |
| 487 | case AF_INET: |
| 488 | local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 489 | salen = sizeof(struct sockaddr_in); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 490 | break; |
| 491 | case AF_INET6: |
| 492 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 493 | salen = sizeof(struct sockaddr_in6); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 494 | break; |
| 495 | default: |
| 496 | local = 0; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 497 | salen = sizeof(struct sockaddr_storage); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 498 | break; |
| 499 | } |
| 500 | if (local) { |
| 501 | debug("Forcing accepting of host key for loopback/localhost."); |
| 502 | return; |
| 503 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 504 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 505 | /* |
| 506 | * Turn off check_host_ip for proxy connects, since |
| 507 | * we don't have the remote ip-address |
| 508 | */ |
| 509 | if (options.proxy_command != NULL && options.check_host_ip) |
| 510 | options.check_host_ip = 0; |
| 511 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 512 | if (options.check_host_ip) { |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 513 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 514 | NULL, 0, NI_NUMERICHOST) != 0) |
| 515 | fatal("check_host_key: getnameinfo failed"); |
| 516 | ip = xstrdup(ntop); |
| 517 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 518 | |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 519 | /* |
| 520 | * Store the host key from the known host file in here so that we can |
| 521 | * compare it with the key for the IP address. |
| 522 | */ |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 523 | file_key = key_new(host_key->type); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 524 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 525 | /* |
| 526 | * Check if the host key is present in the user\'s list of known |
| 527 | * hosts or in the systemwide list. |
| 528 | */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 529 | host_status = check_host_in_hostfile(user_hostfile, host, host_key, file_key); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 530 | if (host_status == HOST_NEW) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 531 | host_status = check_host_in_hostfile(system_hostfile, host, host_key, file_key); |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 532 | /* |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 533 | * Also perform check for the ip address, skip the check if we are |
| 534 | * localhost or the hostname was an ip address to begin with |
| 535 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 536 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 537 | Key *ip_key = key_new(host_key->type); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 538 | ip_status = check_host_in_hostfile(user_hostfile, ip, host_key, ip_key); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 539 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 540 | if (ip_status == HOST_NEW) |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 541 | ip_status = check_host_in_hostfile(system_hostfile, ip, host_key, ip_key); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 542 | if (host_status == HOST_CHANGED && |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 543 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 544 | host_ip_differ = 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 545 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 546 | key_free(ip_key); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 547 | } else |
| 548 | ip_status = host_status; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 549 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 550 | key_free(file_key); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 551 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 552 | switch (host_status) { |
| 553 | case HOST_OK: |
| 554 | /* The host is known and the key matches. */ |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 555 | debug("Host '%.200s' is known and matches the %s host key.", |
| 556 | host, type); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 557 | if (options.check_host_ip) { |
| 558 | if (ip_status == HOST_NEW) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 559 | if (!add_host_to_hostfile(user_hostfile, ip, host_key)) |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 560 | log("Failed to add the %s host key for IP address '%.30s' to the list of known hosts (%.30s).", |
| 561 | type, ip, user_hostfile); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 562 | else |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 563 | log("Warning: Permanently added the %s host key for IP address '%.30s' to the list of known hosts.", |
| 564 | type, ip); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 565 | } else if (ip_status != HOST_OK) |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 566 | log("Warning: the %s host key for '%.200s' differs from the key for the IP address '%.30s'", |
| 567 | type, host, ip); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 568 | } |
| 569 | break; |
| 570 | case HOST_NEW: |
| 571 | /* The host is new. */ |
| 572 | if (options.strict_host_key_checking == 1) { |
| 573 | /* User has requested strict host key checking. We will not add the host key |
| 574 | automatically. The only alternative left is to abort. */ |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 575 | fatal("No %s host key is known for %.200s and you have requested strict checking.", type, host); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 576 | } else if (options.strict_host_key_checking == 2) { |
| 577 | /* The default */ |
| 578 | char prompt[1024]; |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 579 | char *fp = key_fingerprint(host_key); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 580 | snprintf(prompt, sizeof(prompt), |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 581 | "The authenticity of host '%.200s' can't be established.\n" |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 582 | "%s key fingerprint is %s.\n" |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 583 | "Are you sure you want to continue connecting (yes/no)? ", |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 584 | host, type, fp); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 585 | if (!read_yes_or_no(prompt, -1)) |
| 586 | fatal("Aborted by user!\n"); |
| 587 | } |
| 588 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { |
| 589 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); |
| 590 | hostp = hostline; |
| 591 | } else |
| 592 | hostp = host; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 593 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 594 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 595 | if (!add_host_to_hostfile(user_hostfile, hostp, host_key)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 596 | log("Failed to add the host to the list of known hosts (%.500s).", |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 597 | user_hostfile); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 598 | else |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 599 | log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.", |
| 600 | hostp, type); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 601 | break; |
| 602 | case HOST_CHANGED: |
| 603 | if (options.check_host_ip && host_ip_differ) { |
| 604 | char *msg; |
| 605 | if (ip_status == HOST_NEW) |
| 606 | msg = "is unknown"; |
| 607 | else if (ip_status == HOST_OK) |
| 608 | msg = "is unchanged"; |
| 609 | else |
| 610 | msg = "has a different value"; |
| 611 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| 612 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); |
| 613 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 614 | error("The %s host key for %s has changed,", type, host); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 615 | error("and the key for the according IP address %s", ip); |
| 616 | error("%s. This could either mean that", msg); |
| 617 | error("DNS SPOOFING is happening or the IP address for the host"); |
| 618 | error("and its host key have changed at the same time"); |
| 619 | } |
| 620 | /* The host key has changed. */ |
| 621 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
Damien Miller | f039bad | 1999-12-21 20:57:20 +1100 | [diff] [blame] | 622 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 623 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| 624 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); |
| 625 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 626 | error("It is also possible that the %s host key has just been changed.", type); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 627 | error("Please contact your system administrator."); |
| 628 | error("Add correct host key in %.100s to get rid of this message.", |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 629 | user_hostfile); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 630 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 631 | /* |
| 632 | * If strict host key checking is in use, the user will have |
| 633 | * to edit the key manually and we can only abort. |
| 634 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 635 | if (options.strict_host_key_checking) |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 636 | fatal("%s host key for %.200s has changed and you have requested strict checking.", type, host); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 637 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 638 | /* |
| 639 | * If strict host key checking has not been requested, allow |
| 640 | * the connection but without password authentication or |
| 641 | * agent forwarding. |
| 642 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 643 | if (options.password_authentication) { |
| 644 | error("Password authentication is disabled to avoid trojan horses."); |
| 645 | options.password_authentication = 0; |
| 646 | } |
| 647 | if (options.forward_agent) { |
| 648 | error("Agent forwarding is disabled to avoid trojan horses."); |
| 649 | options.forward_agent = 0; |
| 650 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 651 | /* |
| 652 | * XXX Should permit the user to change to use the new id. |
| 653 | * This could be done by converting the host key to an |
| 654 | * identifying sentence, tell that the host identifies itself |
| 655 | * by that sentence, and ask the user if he/she whishes to |
| 656 | * accept the authentication. |
| 657 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 658 | break; |
| 659 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 660 | if (options.check_host_ip) |
| 661 | xfree(ip); |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 662 | } |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 663 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 664 | /* |
| 665 | * Starts a dialog with the server, and authenticates the current user on the |
| 666 | * server. This does not need any extra privileges. The basic connection |
| 667 | * to the server must already have been established before this is called. |
| 668 | * If login fails, this function prints an error and never returns. |
| 669 | * This function does not require super-user privileges. |
| 670 | */ |
| 671 | void |
| 672 | ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost, |
| 673 | struct sockaddr *hostaddr, uid_t original_real_uid) |
| 674 | { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 675 | struct passwd *pw; |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 676 | char *host, *cp; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 677 | char *server_user, *local_user; |
| 678 | |
| 679 | /* Get local user name. Use it as server user if no user name was given. */ |
| 680 | pw = getpwuid(original_real_uid); |
| 681 | if (!pw) |
| 682 | fatal("User id %d not found from user database.", original_real_uid); |
| 683 | local_user = xstrdup(pw->pw_name); |
| 684 | server_user = options.user ? options.user : local_user; |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 685 | |
| 686 | /* Convert the user-supplied hostname into all lowercase. */ |
| 687 | host = xstrdup(orighost); |
| 688 | for (cp = host; *cp; cp++) |
| 689 | if (isupper(*cp)) |
| 690 | *cp = tolower(*cp); |
| 691 | |
| 692 | /* Exchange protocol version identification strings with the server. */ |
| 693 | ssh_exchange_identification(); |
| 694 | |
| 695 | /* Put the connection into non-blocking mode. */ |
| 696 | packet_set_nonblocking(); |
| 697 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 698 | /* key exchange */ |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 699 | /* authenticate user */ |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 700 | if (compat20) { |
| 701 | ssh_kex2(host, hostaddr); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 702 | ssh_userauth2(server_user, host); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 703 | } else { |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 704 | ssh_kex(host, hostaddr); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 705 | ssh_userauth(local_user, server_user, host, host_key_valid, own_host_key); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 706 | } |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 707 | } |