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 |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 5 | * Code to connect to a remote host, and to perform the client side of the |
| 6 | * login (authentication) dialog. |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 7 | * |
| 8 | * As far as I am concerned, the code I have written for this software |
| 9 | * can be used freely for any purpose. Any derived versions of this |
| 10 | * software must be clearly marked as such, and if the derived work is |
| 11 | * incompatible with the protocol description in the RFC file, it must be |
| 12 | * called by a name other than "ssh" or "Secure Shell". |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 13 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 14 | |
| 15 | #include "includes.h" |
Damien Miller | 3c4659c | 2001-01-31 09:52:43 +1100 | [diff] [blame] | 16 | RCSID("$OpenBSD: sshconnect.c,v 1.92 2001/01/30 22:48:52 djm Exp $"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 17 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 18 | #include <openssl/bn.h> |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 19 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 20 | #include "ssh.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 21 | #include "xmalloc.h" |
| 22 | #include "rsa.h" |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 23 | #include "buffer.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 24 | #include "packet.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 25 | #include "uidswap.h" |
| 26 | #include "compat.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 27 | #include "key.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 28 | #include "sshconnect.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 29 | #include "hostfile.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 30 | #include "log.h" |
| 31 | #include "readconf.h" |
| 32 | #include "atomicio.h" |
| 33 | #include "misc.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 34 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 35 | char *client_version_string = NULL; |
| 36 | char *server_version_string = NULL; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 37 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 38 | extern Options options; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 39 | extern char *__progname; |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 40 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 41 | /* AF_UNSPEC or AF_INET or AF_INET6 */ |
| 42 | extern int IPv4or6; |
| 43 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 44 | /* |
| 45 | * Connect to the given ssh server using a proxy command. |
| 46 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 47 | int |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 48 | 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] | 49 | const char *proxy_command) |
| 50 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 51 | Buffer command; |
| 52 | const char *cp; |
| 53 | char *command_string; |
| 54 | int pin[2], pout[2]; |
Damien Miller | 166fca8 | 2000-04-20 07:42:21 +1000 | [diff] [blame] | 55 | pid_t pid; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 56 | char strport[NI_MAXSERV]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 57 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 58 | /* Convert the port number into a string. */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 59 | snprintf(strport, sizeof strport, "%hu", port); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 60 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 61 | /* Build the final command string in the buffer by making the |
| 62 | appropriate substitutions to the given proxy command. */ |
| 63 | buffer_init(&command); |
| 64 | for (cp = proxy_command; *cp; cp++) { |
| 65 | if (cp[0] == '%' && cp[1] == '%') { |
| 66 | buffer_append(&command, "%", 1); |
| 67 | cp++; |
| 68 | continue; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 69 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 70 | if (cp[0] == '%' && cp[1] == 'h') { |
| 71 | buffer_append(&command, host, strlen(host)); |
| 72 | cp++; |
| 73 | continue; |
| 74 | } |
| 75 | if (cp[0] == '%' && cp[1] == 'p') { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 76 | buffer_append(&command, strport, strlen(strport)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 77 | cp++; |
| 78 | continue; |
| 79 | } |
| 80 | buffer_append(&command, cp, 1); |
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 | buffer_append(&command, "\0", 1); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 83 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 84 | /* Get the final command string. */ |
| 85 | command_string = buffer_ptr(&command); |
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 | /* Create pipes for communicating with the proxy. */ |
| 88 | if (pipe(pin) < 0 || pipe(pout) < 0) |
| 89 | fatal("Could not create pipes to communicate with the proxy: %.100s", |
| 90 | strerror(errno)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 91 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 92 | debug("Executing proxy command: %.500s", command_string); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 93 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 94 | /* Fork and execute the proxy command. */ |
| 95 | if ((pid = fork()) == 0) { |
| 96 | char *argv[10]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 97 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 98 | /* Child. Permanently give up superuser privileges. */ |
| 99 | permanently_set_uid(original_real_uid); |
| 100 | |
| 101 | /* Redirect stdin and stdout. */ |
| 102 | close(pin[1]); |
| 103 | if (pin[0] != 0) { |
| 104 | if (dup2(pin[0], 0) < 0) |
| 105 | perror("dup2 stdin"); |
| 106 | close(pin[0]); |
| 107 | } |
| 108 | close(pout[0]); |
| 109 | if (dup2(pout[1], 1) < 0) |
| 110 | perror("dup2 stdout"); |
| 111 | /* Cannot be 1 because pin allocated two descriptors. */ |
| 112 | close(pout[1]); |
| 113 | |
| 114 | /* Stderr is left as it is so that error messages get |
| 115 | printed on the user's terminal. */ |
Damien Miller | 7b413d2 | 2000-07-01 13:24:21 +1000 | [diff] [blame] | 116 | argv[0] = _PATH_BSHELL; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 117 | argv[1] = "-c"; |
| 118 | argv[2] = command_string; |
| 119 | argv[3] = NULL; |
| 120 | |
| 121 | /* Execute the proxy command. Note that we gave up any |
| 122 | extra privileges above. */ |
Kevin Steves | fcd5d60 | 2001-01-07 11:45:22 +0000 | [diff] [blame] | 123 | execv(argv[0], argv); |
| 124 | perror(argv[0]); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 125 | exit(1); |
| 126 | } |
| 127 | /* Parent. */ |
| 128 | if (pid < 0) |
| 129 | fatal("fork failed: %.100s", strerror(errno)); |
| 130 | |
| 131 | /* Close child side of the descriptors. */ |
| 132 | close(pin[0]); |
| 133 | close(pout[1]); |
| 134 | |
| 135 | /* Free the command name. */ |
| 136 | buffer_free(&command); |
| 137 | |
| 138 | /* Set the connection file descriptors. */ |
| 139 | packet_set_connection(pout[0], pin[1]); |
| 140 | |
| 141 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 142 | } |
| 143 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 144 | /* |
| 145 | * Creates a (possibly privileged) socket for use as the ssh connection. |
| 146 | */ |
| 147 | int |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 148 | ssh_create_socket(uid_t original_real_uid, int privileged, int family) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 149 | { |
| 150 | int sock; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 151 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 152 | /* |
| 153 | * If we are running as root and want to connect to a privileged |
| 154 | * port, bind our own socket to a privileged port. |
| 155 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 156 | if (privileged) { |
| 157 | int p = IPPORT_RESERVED - 1; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 158 | sock = rresvport_af(&p, family); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 159 | if (sock < 0) |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 160 | error("rresvport: af=%d %.100s", family, strerror(errno)); |
| 161 | else |
| 162 | debug("Allocated local port %d.", p); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 163 | } else { |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 164 | /* |
| 165 | * Just create an ordinary socket on arbitrary port. We use |
| 166 | * the user's uid to create the socket. |
| 167 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 168 | temporarily_use_uid(original_real_uid); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 169 | sock = socket(family, SOCK_STREAM, 0); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 170 | if (sock < 0) |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 171 | error("socket: %.100s", strerror(errno)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 172 | restore_uid(); |
| 173 | } |
| 174 | return sock; |
| 175 | } |
| 176 | |
| 177 | /* |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 178 | * Opens a TCP/IP connection to the remote server on the given host. |
| 179 | * The address of the remote host will be returned in hostaddr. |
| 180 | * 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] | 181 | * a privileged port will be allocated to make the connection. |
| 182 | * This requires super-user privileges if anonymous is false. |
| 183 | * Connection_attempts specifies the maximum number of tries (one per |
| 184 | * second). If proxy_command is non-NULL, it specifies the command (with %h |
| 185 | * and %p substituted for host and port, respectively) to use to contact |
| 186 | * the daemon. |
| 187 | */ |
| 188 | int |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 189 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 190 | u_short port, int connection_attempts, |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 191 | int anonymous, uid_t original_real_uid, |
| 192 | const char *proxy_command) |
| 193 | { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 194 | int gaierr; |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 195 | int on = 1; |
| 196 | int sock = -1, attempt; |
| 197 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
| 198 | struct addrinfo hints, *ai, *aitop; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 199 | struct linger linger; |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 200 | struct servent *sp; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 201 | |
Damien Miller | caf6dd6 | 2000-08-29 11:33:50 +1100 | [diff] [blame] | 202 | debug("ssh_connect: getuid %u geteuid %u anon %d", |
| 203 | (u_int) getuid(), (u_int) geteuid(), anonymous); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 204 | |
| 205 | /* Get default port if port has not been set. */ |
| 206 | if (port == 0) { |
| 207 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); |
| 208 | if (sp) |
| 209 | port = ntohs(sp->s_port); |
| 210 | else |
| 211 | port = SSH_DEFAULT_PORT; |
| 212 | } |
| 213 | /* If a proxy command is given, connect using it. */ |
| 214 | if (proxy_command != NULL) |
| 215 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); |
| 216 | |
| 217 | /* No proxy command. */ |
| 218 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 219 | memset(&hints, 0, sizeof(hints)); |
| 220 | hints.ai_family = IPv4or6; |
| 221 | hints.ai_socktype = SOCK_STREAM; |
| 222 | snprintf(strport, sizeof strport, "%d", port); |
| 223 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
| 224 | fatal("%s: %.100s: %s", __progname, host, |
| 225 | gai_strerror(gaierr)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 226 | |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 227 | /* |
| 228 | * Try to connect several times. On some machines, the first time |
| 229 | * will sometimes fail. In general socket code appears to behave |
| 230 | * quite magically on many machines. |
| 231 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 232 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
| 233 | if (attempt > 0) |
| 234 | debug("Trying again..."); |
| 235 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 236 | /* Loop through addresses for this host, and try each one in |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 237 | sequence until the connection succeeds. */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 238 | for (ai = aitop; ai; ai = ai->ai_next) { |
| 239 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) |
| 240 | continue; |
| 241 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, |
| 242 | ntop, sizeof(ntop), strport, sizeof(strport), |
| 243 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { |
| 244 | error("ssh_connect: getnameinfo failed"); |
| 245 | continue; |
| 246 | } |
| 247 | debug("Connecting to %.200s [%.100s] port %s.", |
| 248 | host, ntop, strport); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 249 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 250 | /* Create a socket for connecting. */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 251 | sock = ssh_create_socket(original_real_uid, |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 252 | #ifdef HAVE_CYGWIN |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 253 | !anonymous, |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 254 | #else |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 255 | !anonymous && geteuid() == 0, |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 256 | #endif |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 257 | ai->ai_family); |
| 258 | if (sock < 0) |
| 259 | continue; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 260 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 261 | /* Connect to the host. We use the user's uid in the |
| 262 | * hope that it will help with tcp_wrappers showing |
| 263 | * the remote uid as root. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 264 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 265 | temporarily_use_uid(original_real_uid); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 266 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
| 267 | /* Successful connection. */ |
Damien Miller | 95fe91b | 2000-05-13 12:31:22 +1000 | [diff] [blame] | 268 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 269 | restore_uid(); |
| 270 | break; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 271 | } else { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 272 | debug("connect: %.100s", strerror(errno)); |
| 273 | restore_uid(); |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 274 | /* |
| 275 | * Close the failed socket; there appear to |
| 276 | * be some problems when reusing a socket for |
| 277 | * which connect() has already returned an |
| 278 | * error. |
| 279 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 280 | shutdown(sock, SHUT_RDWR); |
| 281 | close(sock); |
| 282 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 283 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 284 | if (ai) |
| 285 | break; /* Successful connection. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 286 | |
| 287 | /* Sleep a moment before retrying. */ |
| 288 | sleep(1); |
| 289 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 290 | |
| 291 | freeaddrinfo(aitop); |
| 292 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 293 | /* Return failure if we didn't get a successful connection. */ |
| 294 | if (attempt >= connection_attempts) |
| 295 | return 0; |
| 296 | |
| 297 | debug("Connection established."); |
| 298 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 299 | /* |
| 300 | * Set socket options. We would like the socket to disappear as soon |
| 301 | * as it has been closed for whatever reason. |
| 302 | */ |
| 303 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 304 | linger.l_onoff = 1; |
| 305 | linger.l_linger = 5; |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 306 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); |
| 307 | |
| 308 | /* Set keepalives if requested. */ |
| 309 | if (options.keepalives && |
| 310 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, |
| 311 | sizeof(on)) < 0) |
| 312 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 313 | |
| 314 | /* Set the connection. */ |
| 315 | packet_set_connection(sock, sock); |
| 316 | |
| 317 | return 1; |
| 318 | } |
| 319 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 320 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 321 | * Waits for the server identification string, and sends our own |
| 322 | * identification string. |
| 323 | */ |
| 324 | void |
| 325 | ssh_exchange_identification() |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 326 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 327 | char buf[256], remote_version[256]; /* must be same size! */ |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 328 | int remote_major, remote_minor, i, mismatch; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 329 | int connection_in = packet_get_connection_in(); |
| 330 | int connection_out = packet_get_connection_out(); |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 331 | int minor1 = PROTOCOL_MINOR_1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 332 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 333 | /* Read other side\'s version identification. */ |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 334 | for (;;) { |
| 335 | for (i = 0; i < sizeof(buf) - 1; i++) { |
| 336 | int len = atomicio(read, connection_in, &buf[i], 1); |
| 337 | if (len < 0) |
| 338 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); |
| 339 | if (len != 1) |
| 340 | fatal("ssh_exchange_identification: Connection closed by remote host"); |
| 341 | if (buf[i] == '\r') { |
| 342 | buf[i] = '\n'; |
| 343 | buf[i + 1] = 0; |
| 344 | continue; /**XXX wait for \n */ |
| 345 | } |
| 346 | if (buf[i] == '\n') { |
| 347 | buf[i + 1] = 0; |
| 348 | break; |
| 349 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 350 | } |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 351 | buf[sizeof(buf) - 1] = 0; |
| 352 | if (strncmp(buf, "SSH-", 4) == 0) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 353 | break; |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 354 | debug("ssh_exchange_identification: %s", buf); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 355 | } |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 356 | server_version_string = xstrdup(buf); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 357 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 358 | /* |
| 359 | * Check that the versions match. In future this might accept |
| 360 | * several versions and set appropriate flags to handle them. |
| 361 | */ |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 362 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", |
| 363 | &remote_major, &remote_minor, remote_version) != 3) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 364 | fatal("Bad remote protocol version identification: '%.100s'", buf); |
| 365 | debug("Remote protocol version %d.%d, remote software version %.100s", |
| 366 | remote_major, remote_minor, remote_version); |
| 367 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 368 | compat_datafellows(remote_version); |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 369 | mismatch = 0; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 370 | |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 371 | switch(remote_major) { |
| 372 | case 1: |
| 373 | if (remote_minor == 99 && |
| 374 | (options.protocol & SSH_PROTO_2) && |
| 375 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { |
| 376 | enable_compat20(); |
| 377 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 378 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 379 | if (!(options.protocol & SSH_PROTO_1)) { |
| 380 | mismatch = 1; |
| 381 | break; |
| 382 | } |
| 383 | if (remote_minor < 3) { |
| 384 | fatal("Remote machine has too old SSH software version."); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 385 | } else if (remote_minor == 3 || remote_minor == 4) { |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 386 | /* We speak 1.3, too. */ |
| 387 | enable_compat13(); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 388 | minor1 = 3; |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 389 | if (options.forward_agent) { |
| 390 | log("Agent forwarding disabled for protocol 1.3"); |
| 391 | options.forward_agent = 0; |
| 392 | } |
| 393 | } |
| 394 | break; |
| 395 | case 2: |
| 396 | if (options.protocol & SSH_PROTO_2) { |
| 397 | enable_compat20(); |
| 398 | break; |
| 399 | } |
| 400 | /* FALLTHROUGH */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 401 | default: |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 402 | mismatch = 1; |
| 403 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 404 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 405 | if (mismatch) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 406 | fatal("Protocol major versions differ: %d vs. %d", |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 407 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
| 408 | remote_major); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 409 | if (compat20) |
| 410 | packet_set_ssh2_format(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 411 | /* Send our own protocol version identification. */ |
| 412 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 413 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 414 | compat20 ? PROTOCOL_MINOR_2 : minor1, |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 415 | SSH_VERSION); |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 416 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 417 | fatal("write: %.100s", strerror(errno)); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 418 | client_version_string = xstrdup(buf); |
| 419 | chop(client_version_string); |
| 420 | chop(server_version_string); |
| 421 | debug("Local version string %.100s", client_version_string); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 422 | } |
| 423 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 424 | int |
| 425 | read_yes_or_no(const char *prompt, int defval) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 426 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 427 | char buf[1024]; |
| 428 | FILE *f; |
| 429 | int retval = -1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 430 | |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 431 | if (isatty(STDIN_FILENO)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 432 | f = stdin; |
| 433 | else |
| 434 | f = fopen("/dev/tty", "rw"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 435 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 436 | if (f == NULL) |
| 437 | return 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 438 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 439 | fflush(stdout); |
| 440 | |
| 441 | while (1) { |
| 442 | fprintf(stderr, "%s", prompt); |
| 443 | if (fgets(buf, sizeof(buf), f) == NULL) { |
| 444 | /* Print a newline (the prompt probably didn\'t have one). */ |
| 445 | fprintf(stderr, "\n"); |
| 446 | strlcpy(buf, "no", sizeof buf); |
| 447 | } |
| 448 | /* Remove newline from response. */ |
| 449 | if (strchr(buf, '\n')) |
| 450 | *strchr(buf, '\n') = 0; |
| 451 | |
| 452 | if (buf[0] == 0) |
| 453 | retval = defval; |
| 454 | if (strcmp(buf, "yes") == 0) |
| 455 | retval = 1; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame] | 456 | else if (strcmp(buf, "no") == 0) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 457 | retval = 0; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame] | 458 | else |
| 459 | fprintf(stderr, "Please type 'yes' or 'no'.\n"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 460 | |
| 461 | if (retval != -1) { |
| 462 | if (f != stdin) |
| 463 | fclose(f); |
| 464 | return retval; |
| 465 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 466 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 467 | } |
| 468 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 469 | /* |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 470 | * check whether the supplied host key is valid, return only if ok. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 471 | */ |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 472 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 473 | void |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 474 | check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key, |
| 475 | const char *user_hostfile, const char *system_hostfile) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 476 | { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 477 | Key *file_key; |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 478 | char *type = key_type(host_key); |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 479 | char *ip = NULL; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 480 | char hostline[1000], *hostp; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 481 | HostStatus host_status; |
| 482 | HostStatus ip_status; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 483 | int local = 0, host_ip_differ = 0; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 484 | int salen; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 485 | char ntop[NI_MAXHOST]; |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 486 | int host_line, ip_line; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 487 | const char *host_file = NULL, *ip_file = NULL; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 488 | |
| 489 | /* |
| 490 | * Force accepting of the host key for loopback/localhost. The |
| 491 | * problem is that if the home directory is NFS-mounted to multiple |
| 492 | * machines, localhost will refer to a different machine in each of |
| 493 | * them, and the user will get bogus HOST_CHANGED warnings. This |
| 494 | * essentially disables host authentication for localhost; however, |
| 495 | * this is probably not a real problem. |
| 496 | */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 497 | /** hostaddr == 0! */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 498 | switch (hostaddr->sa_family) { |
| 499 | case AF_INET: |
| 500 | 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] | 501 | salen = sizeof(struct sockaddr_in); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 502 | break; |
| 503 | case AF_INET6: |
| 504 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 505 | salen = sizeof(struct sockaddr_in6); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 506 | break; |
| 507 | default: |
| 508 | local = 0; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 509 | salen = sizeof(struct sockaddr_storage); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 510 | break; |
| 511 | } |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 512 | if (local && options.host_key_alias == NULL) { |
| 513 | debug("Forcing accepting of host key for " |
| 514 | "loopback/localhost."); |
| 515 | return; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 516 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 517 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 518 | /* |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 519 | * We don't have the remote ip-address for connections |
| 520 | * using a proxy command |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 521 | */ |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 522 | if (options.proxy_command == NULL) { |
| 523 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), |
| 524 | NULL, 0, NI_NUMERICHOST) != 0) |
| 525 | fatal("check_host_key: getnameinfo failed"); |
| 526 | ip = xstrdup(ntop); |
| 527 | } else { |
| 528 | ip = xstrdup("<no hostip for proxy command>"); |
| 529 | } |
| 530 | /* |
| 531 | * Turn off check_host_ip if the connection is to localhost, via proxy |
| 532 | * command or if we don't have a hostname to compare with |
| 533 | */ |
| 534 | if (options.check_host_ip && |
| 535 | (local || strcmp(host, ip) == 0 || options.proxy_command != NULL)) |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 536 | options.check_host_ip = 0; |
| 537 | |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 538 | /* |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 539 | * Allow the user to record the key under a different name. This is |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 540 | * useful for ssh tunneling over forwarded connections or if you run |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 541 | * multiple sshd's on different ports on the same machine. |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 542 | */ |
| 543 | if (options.host_key_alias != NULL) { |
| 544 | host = options.host_key_alias; |
| 545 | debug("using hostkeyalias: %s", host); |
| 546 | } |
| 547 | |
| 548 | /* |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 549 | * Store the host key from the known host file in here so that we can |
| 550 | * compare it with the key for the IP address. |
| 551 | */ |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 552 | file_key = key_new(host_key->type); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 553 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 554 | /* |
| 555 | * Check if the host key is present in the user\'s list of known |
| 556 | * hosts or in the systemwide list. |
| 557 | */ |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 558 | host_file = user_hostfile; |
| 559 | host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line); |
| 560 | if (host_status == HOST_NEW) { |
| 561 | host_file = system_hostfile; |
| 562 | host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line); |
| 563 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 564 | /* |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 565 | * Also perform check for the ip address, skip the check if we are |
| 566 | * localhost or the hostname was an ip address to begin with |
| 567 | */ |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 568 | if (options.check_host_ip) { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 569 | Key *ip_key = key_new(host_key->type); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 570 | |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 571 | ip_file = user_hostfile; |
| 572 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line); |
| 573 | if (ip_status == HOST_NEW) { |
| 574 | ip_file = system_hostfile; |
| 575 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line); |
| 576 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 577 | if (host_status == HOST_CHANGED && |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 578 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 579 | host_ip_differ = 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 580 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 581 | key_free(ip_key); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 582 | } else |
| 583 | ip_status = host_status; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 584 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 585 | key_free(file_key); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 586 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 587 | switch (host_status) { |
| 588 | case HOST_OK: |
| 589 | /* The host is known and the key matches. */ |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 590 | debug("Host '%.200s' is known and matches the %s host key.", |
| 591 | host, type); |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 592 | debug("Found key in %s:%d", host_file, host_line); |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 593 | if (options.check_host_ip && ip_status == HOST_NEW) { |
| 594 | if (!add_host_to_hostfile(user_hostfile, ip, host_key)) |
| 595 | log("Failed to add the %s host key for IP address '%.30s' to the list of known hosts (%.30s).", |
| 596 | type, ip, user_hostfile); |
| 597 | else |
| 598 | log("Warning: Permanently added the %s host key for IP address '%.30s' to the list of known hosts.", |
| 599 | type, ip); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 600 | } |
| 601 | break; |
| 602 | case HOST_NEW: |
| 603 | /* The host is new. */ |
| 604 | if (options.strict_host_key_checking == 1) { |
| 605 | /* User has requested strict host key checking. We will not add the host key |
| 606 | automatically. The only alternative left is to abort. */ |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 607 | 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] | 608 | } else if (options.strict_host_key_checking == 2) { |
| 609 | /* The default */ |
| 610 | char prompt[1024]; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 611 | snprintf(prompt, sizeof(prompt), |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 612 | "The authenticity of host '%.200s (%s)' can't be established.\n" |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 613 | "%s key fingerprint is %s.\n" |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 614 | "Are you sure you want to continue connecting (yes/no)? ", |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 615 | host, ip, type, key_fingerprint(host_key)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 616 | if (!read_yes_or_no(prompt, -1)) |
| 617 | fatal("Aborted by user!\n"); |
| 618 | } |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 619 | if (options.check_host_ip && ip_status == HOST_NEW) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 620 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); |
| 621 | hostp = hostline; |
| 622 | } else |
| 623 | hostp = host; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 624 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 625 | /* 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] | 626 | if (!add_host_to_hostfile(user_hostfile, hostp, host_key)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 627 | 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] | 628 | user_hostfile); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 629 | else |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 630 | log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.", |
| 631 | hostp, type); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 632 | break; |
| 633 | case HOST_CHANGED: |
| 634 | if (options.check_host_ip && host_ip_differ) { |
| 635 | char *msg; |
| 636 | if (ip_status == HOST_NEW) |
| 637 | msg = "is unknown"; |
| 638 | else if (ip_status == HOST_OK) |
| 639 | msg = "is unchanged"; |
| 640 | else |
| 641 | msg = "has a different value"; |
| 642 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| 643 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); |
| 644 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 645 | error("The %s host key for %s has changed,", type, host); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 646 | error("and the key for the according IP address %s", ip); |
| 647 | error("%s. This could either mean that", msg); |
| 648 | error("DNS SPOOFING is happening or the IP address for the host"); |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 649 | error("and its host key have changed at the same time."); |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 650 | if (ip_status != HOST_NEW) |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 651 | error("Offending key for IP in %s:%d", ip_file, ip_line); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 652 | } |
| 653 | /* The host key has changed. */ |
| 654 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
Damien Miller | f039bad | 1999-12-21 20:57:20 +1100 | [diff] [blame] | 655 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 656 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| 657 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); |
| 658 | 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] | 659 | error("It is also possible that the %s host key has just been changed.", type); |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 660 | error("The fingerprint for the %s key sent by the remote host is\n%s.", |
| 661 | type, key_fingerprint(host_key)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 662 | error("Please contact your system administrator."); |
| 663 | error("Add correct host key in %.100s to get rid of this message.", |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 664 | user_hostfile); |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 665 | error("Offending key in %s:%d", host_file, host_line); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 666 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 667 | /* |
| 668 | * If strict host key checking is in use, the user will have |
| 669 | * to edit the key manually and we can only abort. |
| 670 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 671 | if (options.strict_host_key_checking) |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 672 | 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] | 673 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 674 | /* |
| 675 | * If strict host key checking has not been requested, allow |
| 676 | * the connection but without password authentication or |
| 677 | * agent forwarding. |
| 678 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 679 | if (options.password_authentication) { |
| 680 | error("Password authentication is disabled to avoid trojan horses."); |
| 681 | options.password_authentication = 0; |
| 682 | } |
| 683 | if (options.forward_agent) { |
| 684 | error("Agent forwarding is disabled to avoid trojan horses."); |
| 685 | options.forward_agent = 0; |
| 686 | } |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 687 | if (options.forward_x11) { |
| 688 | error("X11 forwarding is disabled to avoid trojan horses."); |
| 689 | options.forward_x11 = 0; |
| 690 | } |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 691 | if (options.num_local_forwards > 0 || options.num_remote_forwards > 0) { |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 692 | error("Port forwarding is disabled to avoid trojan horses."); |
| 693 | options.num_local_forwards = options.num_remote_forwards = 0; |
| 694 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 695 | /* |
| 696 | * XXX Should permit the user to change to use the new id. |
| 697 | * This could be done by converting the host key to an |
| 698 | * identifying sentence, tell that the host identifies itself |
| 699 | * by that sentence, and ask the user if he/she whishes to |
| 700 | * accept the authentication. |
| 701 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 702 | break; |
| 703 | } |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 704 | |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 705 | if (options.check_host_ip && host_status != HOST_CHANGED && |
| 706 | ip_status == HOST_CHANGED) { |
| 707 | log("Warning: the %s host key for '%.200s' " |
| 708 | "differs from the key for the IP address '%.30s'", |
| 709 | type, host, ip); |
| 710 | if (host_status == HOST_OK) |
| 711 | log("Matching host key in %s:%d", host_file, host_line); |
| 712 | log("Offending key for IP in %s:%d", ip_file, ip_line); |
| 713 | if (options.strict_host_key_checking == 1) { |
| 714 | fatal("Exiting, you have requested strict checking."); |
| 715 | } else if (options.strict_host_key_checking == 2) { |
Damien Miller | 3c4659c | 2001-01-31 09:52:43 +1100 | [diff] [blame] | 716 | if (!read_yes_or_no("Are you sure you want " \ |
| 717 | "to continue connecting (yes/no)? ", -1)) |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 718 | fatal("Aborted by user!\n"); |
| 719 | } |
| 720 | } |
| 721 | |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 722 | xfree(ip); |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 723 | } |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 724 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 725 | /* |
| 726 | * Starts a dialog with the server, and authenticates the current user on the |
| 727 | * server. This does not need any extra privileges. The basic connection |
| 728 | * to the server must already have been established before this is called. |
| 729 | * If login fails, this function prints an error and never returns. |
| 730 | * This function does not require super-user privileges. |
| 731 | */ |
| 732 | void |
| 733 | ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost, |
| 734 | struct sockaddr *hostaddr, uid_t original_real_uid) |
| 735 | { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 736 | struct passwd *pw; |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 737 | char *host, *cp; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 738 | char *server_user, *local_user; |
| 739 | |
| 740 | /* Get local user name. Use it as server user if no user name was given. */ |
| 741 | pw = getpwuid(original_real_uid); |
| 742 | if (!pw) |
Damien Miller | caf6dd6 | 2000-08-29 11:33:50 +1100 | [diff] [blame] | 743 | fatal("User id %u not found from user database.", original_real_uid); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 744 | local_user = xstrdup(pw->pw_name); |
| 745 | server_user = options.user ? options.user : local_user; |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 746 | |
| 747 | /* Convert the user-supplied hostname into all lowercase. */ |
| 748 | host = xstrdup(orighost); |
| 749 | for (cp = host; *cp; cp++) |
| 750 | if (isupper(*cp)) |
| 751 | *cp = tolower(*cp); |
| 752 | |
| 753 | /* Exchange protocol version identification strings with the server. */ |
| 754 | ssh_exchange_identification(); |
| 755 | |
| 756 | /* Put the connection into non-blocking mode. */ |
| 757 | packet_set_nonblocking(); |
| 758 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 759 | /* key exchange */ |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 760 | /* authenticate user */ |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 761 | if (compat20) { |
| 762 | ssh_kex2(host, hostaddr); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 763 | ssh_userauth2(server_user, host); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 764 | } else { |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 765 | ssh_kex(host, hostaddr); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 766 | 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] | 767 | } |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 768 | } |