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" |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame^] | 16 | RCSID("$OpenBSD: sshconnect.c,v 1.90 2001/01/13 18:32:50 markus 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 | #include <openssl/dsa.h> |
| 20 | #include <openssl/rsa.h> |
| 21 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 22 | #include "xmalloc.h" |
| 23 | #include "rsa.h" |
| 24 | #include "ssh.h" |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 25 | #include "buffer.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 26 | #include "packet.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 27 | #include "uidswap.h" |
| 28 | #include "compat.h" |
Damien Miller | 6d7b2cd | 1999-11-12 15:19:27 +1100 | [diff] [blame] | 29 | #include "readconf.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 30 | #include "key.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 31 | #include "sshconnect.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 32 | #include "hostfile.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 33 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 34 | char *client_version_string = NULL; |
| 35 | char *server_version_string = NULL; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 36 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 37 | extern Options options; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 38 | extern char *__progname; |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 39 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 40 | /* |
| 41 | * Connect to the given ssh server using a proxy command. |
| 42 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 43 | int |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 44 | 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] | 45 | const char *proxy_command) |
| 46 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 47 | Buffer command; |
| 48 | const char *cp; |
| 49 | char *command_string; |
| 50 | int pin[2], pout[2]; |
Damien Miller | 166fca8 | 2000-04-20 07:42:21 +1000 | [diff] [blame] | 51 | pid_t pid; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 52 | char strport[NI_MAXSERV]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 53 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 54 | /* Convert the port number into a string. */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 55 | snprintf(strport, sizeof strport, "%hu", port); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 56 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 57 | /* Build the final command string in the buffer by making the |
| 58 | appropriate substitutions to the given proxy command. */ |
| 59 | buffer_init(&command); |
| 60 | for (cp = proxy_command; *cp; cp++) { |
| 61 | if (cp[0] == '%' && cp[1] == '%') { |
| 62 | buffer_append(&command, "%", 1); |
| 63 | cp++; |
| 64 | continue; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 65 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 66 | if (cp[0] == '%' && cp[1] == 'h') { |
| 67 | buffer_append(&command, host, strlen(host)); |
| 68 | cp++; |
| 69 | continue; |
| 70 | } |
| 71 | if (cp[0] == '%' && cp[1] == 'p') { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 72 | buffer_append(&command, strport, strlen(strport)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 73 | cp++; |
| 74 | continue; |
| 75 | } |
| 76 | buffer_append(&command, cp, 1); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 77 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 78 | buffer_append(&command, "\0", 1); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 79 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 80 | /* Get the final command string. */ |
| 81 | command_string = buffer_ptr(&command); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 82 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 83 | /* Create pipes for communicating with the proxy. */ |
| 84 | if (pipe(pin) < 0 || pipe(pout) < 0) |
| 85 | fatal("Could not create pipes to communicate with the proxy: %.100s", |
| 86 | strerror(errno)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 87 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 88 | debug("Executing proxy command: %.500s", command_string); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 89 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 90 | /* Fork and execute the proxy command. */ |
| 91 | if ((pid = fork()) == 0) { |
| 92 | char *argv[10]; |
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 | /* Child. Permanently give up superuser privileges. */ |
| 95 | permanently_set_uid(original_real_uid); |
| 96 | |
| 97 | /* Redirect stdin and stdout. */ |
| 98 | close(pin[1]); |
| 99 | if (pin[0] != 0) { |
| 100 | if (dup2(pin[0], 0) < 0) |
| 101 | perror("dup2 stdin"); |
| 102 | close(pin[0]); |
| 103 | } |
| 104 | close(pout[0]); |
| 105 | if (dup2(pout[1], 1) < 0) |
| 106 | perror("dup2 stdout"); |
| 107 | /* Cannot be 1 because pin allocated two descriptors. */ |
| 108 | close(pout[1]); |
| 109 | |
| 110 | /* Stderr is left as it is so that error messages get |
| 111 | printed on the user's terminal. */ |
Damien Miller | 7b413d2 | 2000-07-01 13:24:21 +1000 | [diff] [blame] | 112 | argv[0] = _PATH_BSHELL; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 113 | argv[1] = "-c"; |
| 114 | argv[2] = command_string; |
| 115 | argv[3] = NULL; |
| 116 | |
| 117 | /* Execute the proxy command. Note that we gave up any |
| 118 | extra privileges above. */ |
Kevin Steves | fcd5d60 | 2001-01-07 11:45:22 +0000 | [diff] [blame] | 119 | execv(argv[0], argv); |
| 120 | perror(argv[0]); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 121 | exit(1); |
| 122 | } |
| 123 | /* Parent. */ |
| 124 | if (pid < 0) |
| 125 | fatal("fork failed: %.100s", strerror(errno)); |
| 126 | |
| 127 | /* Close child side of the descriptors. */ |
| 128 | close(pin[0]); |
| 129 | close(pout[1]); |
| 130 | |
| 131 | /* Free the command name. */ |
| 132 | buffer_free(&command); |
| 133 | |
| 134 | /* Set the connection file descriptors. */ |
| 135 | packet_set_connection(pout[0], pin[1]); |
| 136 | |
| 137 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 138 | } |
| 139 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 140 | /* |
| 141 | * Creates a (possibly privileged) socket for use as the ssh connection. |
| 142 | */ |
| 143 | int |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 144 | ssh_create_socket(uid_t original_real_uid, int privileged, int family) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 145 | { |
| 146 | int sock; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 147 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 148 | /* |
| 149 | * If we are running as root and want to connect to a privileged |
| 150 | * port, bind our own socket to a privileged port. |
| 151 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 152 | if (privileged) { |
| 153 | int p = IPPORT_RESERVED - 1; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 154 | sock = rresvport_af(&p, family); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 155 | if (sock < 0) |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 156 | error("rresvport: af=%d %.100s", family, strerror(errno)); |
| 157 | else |
| 158 | debug("Allocated local port %d.", p); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 159 | } else { |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 160 | /* |
| 161 | * Just create an ordinary socket on arbitrary port. We use |
| 162 | * the user's uid to create the socket. |
| 163 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 164 | temporarily_use_uid(original_real_uid); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 165 | sock = socket(family, SOCK_STREAM, 0); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 166 | if (sock < 0) |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 167 | error("socket: %.100s", strerror(errno)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 168 | restore_uid(); |
| 169 | } |
| 170 | return sock; |
| 171 | } |
| 172 | |
| 173 | /* |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 174 | * Opens a TCP/IP connection to the remote server on the given host. |
| 175 | * The address of the remote host will be returned in hostaddr. |
| 176 | * 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] | 177 | * a privileged port will be allocated to make the connection. |
| 178 | * This requires super-user privileges if anonymous is false. |
| 179 | * Connection_attempts specifies the maximum number of tries (one per |
| 180 | * second). If proxy_command is non-NULL, it specifies the command (with %h |
| 181 | * and %p substituted for host and port, respectively) to use to contact |
| 182 | * the daemon. |
| 183 | */ |
| 184 | int |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 185 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 186 | u_short port, int connection_attempts, |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 187 | int anonymous, uid_t original_real_uid, |
| 188 | const char *proxy_command) |
| 189 | { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 190 | int gaierr; |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame^] | 191 | int on = 1; |
| 192 | int sock = -1, attempt; |
| 193 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
| 194 | struct addrinfo hints, *ai, *aitop; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 195 | struct linger linger; |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame^] | 196 | struct servent *sp; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 197 | |
Damien Miller | caf6dd6 | 2000-08-29 11:33:50 +1100 | [diff] [blame] | 198 | debug("ssh_connect: getuid %u geteuid %u anon %d", |
| 199 | (u_int) getuid(), (u_int) geteuid(), anonymous); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 200 | |
| 201 | /* Get default port if port has not been set. */ |
| 202 | if (port == 0) { |
| 203 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); |
| 204 | if (sp) |
| 205 | port = ntohs(sp->s_port); |
| 206 | else |
| 207 | port = SSH_DEFAULT_PORT; |
| 208 | } |
| 209 | /* If a proxy command is given, connect using it. */ |
| 210 | if (proxy_command != NULL) |
| 211 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); |
| 212 | |
| 213 | /* No proxy command. */ |
| 214 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 215 | memset(&hints, 0, sizeof(hints)); |
| 216 | hints.ai_family = IPv4or6; |
| 217 | hints.ai_socktype = SOCK_STREAM; |
| 218 | snprintf(strport, sizeof strport, "%d", port); |
| 219 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
| 220 | fatal("%s: %.100s: %s", __progname, host, |
| 221 | gai_strerror(gaierr)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 222 | |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 223 | /* |
| 224 | * Try to connect several times. On some machines, the first time |
| 225 | * will sometimes fail. In general socket code appears to behave |
| 226 | * quite magically on many machines. |
| 227 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 228 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
| 229 | if (attempt > 0) |
| 230 | debug("Trying again..."); |
| 231 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 232 | /* Loop through addresses for this host, and try each one in |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 233 | sequence until the connection succeeds. */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 234 | for (ai = aitop; ai; ai = ai->ai_next) { |
| 235 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) |
| 236 | continue; |
| 237 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, |
| 238 | ntop, sizeof(ntop), strport, sizeof(strport), |
| 239 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { |
| 240 | error("ssh_connect: getnameinfo failed"); |
| 241 | continue; |
| 242 | } |
| 243 | debug("Connecting to %.200s [%.100s] port %s.", |
| 244 | host, ntop, strport); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 245 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 246 | /* Create a socket for connecting. */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 247 | sock = ssh_create_socket(original_real_uid, |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 248 | #ifdef HAVE_CYGWIN |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 249 | !anonymous, |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 250 | #else |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 251 | !anonymous && geteuid() == 0, |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 252 | #endif |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 253 | ai->ai_family); |
| 254 | if (sock < 0) |
| 255 | continue; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 256 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 257 | /* Connect to the host. We use the user's uid in the |
| 258 | * hope that it will help with tcp_wrappers showing |
| 259 | * the remote uid as root. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 260 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 261 | temporarily_use_uid(original_real_uid); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 262 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
| 263 | /* Successful connection. */ |
Damien Miller | 95fe91b | 2000-05-13 12:31:22 +1000 | [diff] [blame] | 264 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 265 | restore_uid(); |
| 266 | break; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 267 | } else { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 268 | debug("connect: %.100s", strerror(errno)); |
| 269 | restore_uid(); |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 270 | /* |
| 271 | * Close the failed socket; there appear to |
| 272 | * be some problems when reusing a socket for |
| 273 | * which connect() has already returned an |
| 274 | * error. |
| 275 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 276 | shutdown(sock, SHUT_RDWR); |
| 277 | close(sock); |
| 278 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 279 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 280 | if (ai) |
| 281 | break; /* Successful connection. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 282 | |
| 283 | /* Sleep a moment before retrying. */ |
| 284 | sleep(1); |
| 285 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 286 | |
| 287 | freeaddrinfo(aitop); |
| 288 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 289 | /* Return failure if we didn't get a successful connection. */ |
| 290 | if (attempt >= connection_attempts) |
| 291 | return 0; |
| 292 | |
| 293 | debug("Connection established."); |
| 294 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 295 | /* |
| 296 | * Set socket options. We would like the socket to disappear as soon |
| 297 | * as it has been closed for whatever reason. |
| 298 | */ |
| 299 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 300 | linger.l_onoff = 1; |
| 301 | linger.l_linger = 5; |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame^] | 302 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); |
| 303 | |
| 304 | /* Set keepalives if requested. */ |
| 305 | if (options.keepalives && |
| 306 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, |
| 307 | sizeof(on)) < 0) |
| 308 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 309 | |
| 310 | /* Set the connection. */ |
| 311 | packet_set_connection(sock, sock); |
| 312 | |
| 313 | return 1; |
| 314 | } |
| 315 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 316 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 317 | * Waits for the server identification string, and sends our own |
| 318 | * identification string. |
| 319 | */ |
| 320 | void |
| 321 | ssh_exchange_identification() |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 322 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 323 | char buf[256], remote_version[256]; /* must be same size! */ |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 324 | int remote_major, remote_minor, i, mismatch; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 325 | int connection_in = packet_get_connection_in(); |
| 326 | int connection_out = packet_get_connection_out(); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 327 | int minor1 = PROTOCOL_MINOR_1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 328 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 329 | /* Read other side\'s version identification. */ |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 330 | for (;;) { |
| 331 | for (i = 0; i < sizeof(buf) - 1; i++) { |
| 332 | int len = atomicio(read, connection_in, &buf[i], 1); |
| 333 | if (len < 0) |
| 334 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); |
| 335 | if (len != 1) |
| 336 | fatal("ssh_exchange_identification: Connection closed by remote host"); |
| 337 | if (buf[i] == '\r') { |
| 338 | buf[i] = '\n'; |
| 339 | buf[i + 1] = 0; |
| 340 | continue; /**XXX wait for \n */ |
| 341 | } |
| 342 | if (buf[i] == '\n') { |
| 343 | buf[i + 1] = 0; |
| 344 | break; |
| 345 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 346 | } |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 347 | buf[sizeof(buf) - 1] = 0; |
| 348 | if (strncmp(buf, "SSH-", 4) == 0) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 349 | break; |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 350 | debug("ssh_exchange_identification: %s", buf); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 351 | } |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 352 | server_version_string = xstrdup(buf); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 353 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 354 | /* |
| 355 | * Check that the versions match. In future this might accept |
| 356 | * several versions and set appropriate flags to handle them. |
| 357 | */ |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 358 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", |
| 359 | &remote_major, &remote_minor, remote_version) != 3) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 360 | fatal("Bad remote protocol version identification: '%.100s'", buf); |
| 361 | debug("Remote protocol version %d.%d, remote software version %.100s", |
| 362 | remote_major, remote_minor, remote_version); |
| 363 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 364 | compat_datafellows(remote_version); |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 365 | mismatch = 0; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 366 | |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 367 | switch(remote_major) { |
| 368 | case 1: |
| 369 | if (remote_minor == 99 && |
| 370 | (options.protocol & SSH_PROTO_2) && |
| 371 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { |
| 372 | enable_compat20(); |
| 373 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 374 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 375 | if (!(options.protocol & SSH_PROTO_1)) { |
| 376 | mismatch = 1; |
| 377 | break; |
| 378 | } |
| 379 | if (remote_minor < 3) { |
| 380 | fatal("Remote machine has too old SSH software version."); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 381 | } else if (remote_minor == 3 || remote_minor == 4) { |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 382 | /* We speak 1.3, too. */ |
| 383 | enable_compat13(); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 384 | minor1 = 3; |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 385 | if (options.forward_agent) { |
| 386 | log("Agent forwarding disabled for protocol 1.3"); |
| 387 | options.forward_agent = 0; |
| 388 | } |
| 389 | } |
| 390 | break; |
| 391 | case 2: |
| 392 | if (options.protocol & SSH_PROTO_2) { |
| 393 | enable_compat20(); |
| 394 | break; |
| 395 | } |
| 396 | /* FALLTHROUGH */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 397 | default: |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 398 | mismatch = 1; |
| 399 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 400 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 401 | if (mismatch) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 402 | fatal("Protocol major versions differ: %d vs. %d", |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 403 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
| 404 | remote_major); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 405 | if (compat20) |
| 406 | packet_set_ssh2_format(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 407 | /* Send our own protocol version identification. */ |
| 408 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 409 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 410 | compat20 ? PROTOCOL_MINOR_2 : minor1, |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 411 | SSH_VERSION); |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 412 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 413 | fatal("write: %.100s", strerror(errno)); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 414 | client_version_string = xstrdup(buf); |
| 415 | chop(client_version_string); |
| 416 | chop(server_version_string); |
| 417 | debug("Local version string %.100s", client_version_string); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 418 | } |
| 419 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 420 | int |
| 421 | read_yes_or_no(const char *prompt, int defval) |
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 | char buf[1024]; |
| 424 | FILE *f; |
| 425 | int retval = -1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 426 | |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 427 | if (isatty(STDIN_FILENO)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 428 | f = stdin; |
| 429 | else |
| 430 | f = fopen("/dev/tty", "rw"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 431 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 432 | if (f == NULL) |
| 433 | return 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 434 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 435 | fflush(stdout); |
| 436 | |
| 437 | while (1) { |
| 438 | fprintf(stderr, "%s", prompt); |
| 439 | if (fgets(buf, sizeof(buf), f) == NULL) { |
| 440 | /* Print a newline (the prompt probably didn\'t have one). */ |
| 441 | fprintf(stderr, "\n"); |
| 442 | strlcpy(buf, "no", sizeof buf); |
| 443 | } |
| 444 | /* Remove newline from response. */ |
| 445 | if (strchr(buf, '\n')) |
| 446 | *strchr(buf, '\n') = 0; |
| 447 | |
| 448 | if (buf[0] == 0) |
| 449 | retval = defval; |
| 450 | if (strcmp(buf, "yes") == 0) |
| 451 | retval = 1; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame] | 452 | else if (strcmp(buf, "no") == 0) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 453 | retval = 0; |
Damien Miller | 62cee00 | 2000-09-23 17:15:56 +1100 | [diff] [blame] | 454 | else |
| 455 | fprintf(stderr, "Please type 'yes' or 'no'.\n"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 456 | |
| 457 | if (retval != -1) { |
| 458 | if (f != stdin) |
| 459 | fclose(f); |
| 460 | return retval; |
| 461 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 462 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 463 | } |
| 464 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 465 | /* |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 466 | * check whether the supplied host key is valid, return only if ok. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 467 | */ |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 468 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 469 | void |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 470 | check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key, |
| 471 | const char *user_hostfile, const char *system_hostfile) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 472 | { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 473 | Key *file_key; |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 474 | char *type = key_type(host_key); |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 475 | char *ip = NULL; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 476 | char hostline[1000], *hostp; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 477 | HostStatus host_status; |
| 478 | HostStatus ip_status; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 479 | int local = 0, host_ip_differ = 0; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 480 | int salen; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 481 | char ntop[NI_MAXHOST]; |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 482 | int host_line, ip_line; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 483 | const char *host_file = NULL, *ip_file = NULL; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 484 | |
| 485 | /* |
| 486 | * Force accepting of the host key for loopback/localhost. The |
| 487 | * problem is that if the home directory is NFS-mounted to multiple |
| 488 | * machines, localhost will refer to a different machine in each of |
| 489 | * them, and the user will get bogus HOST_CHANGED warnings. This |
| 490 | * essentially disables host authentication for localhost; however, |
| 491 | * this is probably not a real problem. |
| 492 | */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 493 | /** hostaddr == 0! */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 494 | switch (hostaddr->sa_family) { |
| 495 | case AF_INET: |
| 496 | 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] | 497 | salen = sizeof(struct sockaddr_in); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 498 | break; |
| 499 | case AF_INET6: |
| 500 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 501 | salen = sizeof(struct sockaddr_in6); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 502 | break; |
| 503 | default: |
| 504 | local = 0; |
Damien Miller | eaf9994 | 2000-01-19 13:45:07 +1100 | [diff] [blame] | 505 | salen = sizeof(struct sockaddr_storage); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 506 | break; |
| 507 | } |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 508 | if (local && options.host_key_alias == NULL) { |
| 509 | debug("Forcing accepting of host key for " |
| 510 | "loopback/localhost."); |
| 511 | return; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 512 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 513 | |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 514 | /* |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 515 | * We don't have the remote ip-address for connections |
| 516 | * using a proxy command |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 517 | */ |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 518 | if (options.proxy_command == NULL) { |
| 519 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), |
| 520 | NULL, 0, NI_NUMERICHOST) != 0) |
| 521 | fatal("check_host_key: getnameinfo failed"); |
| 522 | ip = xstrdup(ntop); |
| 523 | } else { |
| 524 | ip = xstrdup("<no hostip for proxy command>"); |
| 525 | } |
| 526 | /* |
| 527 | * Turn off check_host_ip if the connection is to localhost, via proxy |
| 528 | * command or if we don't have a hostname to compare with |
| 529 | */ |
| 530 | if (options.check_host_ip && |
| 531 | (local || strcmp(host, ip) == 0 || options.proxy_command != NULL)) |
Damien Miller | aae6c61 | 1999-12-06 11:47:28 +1100 | [diff] [blame] | 532 | options.check_host_ip = 0; |
| 533 | |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 534 | /* |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 535 | * 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] | 536 | * useful for ssh tunneling over forwarded connections or if you run |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 537 | * multiple sshd's on different ports on the same machine. |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 538 | */ |
| 539 | if (options.host_key_alias != NULL) { |
| 540 | host = options.host_key_alias; |
| 541 | debug("using hostkeyalias: %s", host); |
| 542 | } |
| 543 | |
| 544 | /* |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 545 | * Store the host key from the known host file in here so that we can |
| 546 | * compare it with the key for the IP address. |
| 547 | */ |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 548 | file_key = key_new(host_key->type); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 549 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 550 | /* |
| 551 | * Check if the host key is present in the user\'s list of known |
| 552 | * hosts or in the systemwide list. |
| 553 | */ |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 554 | host_file = user_hostfile; |
| 555 | host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line); |
| 556 | if (host_status == HOST_NEW) { |
| 557 | host_file = system_hostfile; |
| 558 | host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line); |
| 559 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 560 | /* |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 561 | * Also perform check for the ip address, skip the check if we are |
| 562 | * localhost or the hostname was an ip address to begin with |
| 563 | */ |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 564 | if (options.check_host_ip) { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 565 | Key *ip_key = key_new(host_key->type); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 566 | |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 567 | ip_file = user_hostfile; |
| 568 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line); |
| 569 | if (ip_status == HOST_NEW) { |
| 570 | ip_file = system_hostfile; |
| 571 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line); |
| 572 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 573 | if (host_status == HOST_CHANGED && |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 574 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 575 | host_ip_differ = 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 576 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 577 | key_free(ip_key); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 578 | } else |
| 579 | ip_status = host_status; |
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(file_key); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 582 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 583 | switch (host_status) { |
| 584 | case HOST_OK: |
| 585 | /* The host is known and the key matches. */ |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 586 | debug("Host '%.200s' is known and matches the %s host key.", |
| 587 | host, type); |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 588 | debug("Found key in %s:%d", host_file, host_line); |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 589 | if (options.check_host_ip && ip_status == HOST_NEW) { |
| 590 | if (!add_host_to_hostfile(user_hostfile, ip, host_key)) |
| 591 | log("Failed to add the %s host key for IP address '%.30s' to the list of known hosts (%.30s).", |
| 592 | type, ip, user_hostfile); |
| 593 | else |
| 594 | log("Warning: Permanently added the %s host key for IP address '%.30s' to the list of known hosts.", |
| 595 | type, ip); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 596 | } |
| 597 | break; |
| 598 | case HOST_NEW: |
| 599 | /* The host is new. */ |
| 600 | if (options.strict_host_key_checking == 1) { |
| 601 | /* User has requested strict host key checking. We will not add the host key |
| 602 | automatically. The only alternative left is to abort. */ |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 603 | 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] | 604 | } else if (options.strict_host_key_checking == 2) { |
| 605 | /* The default */ |
| 606 | char prompt[1024]; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 607 | snprintf(prompt, sizeof(prompt), |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 608 | "The authenticity of host '%.200s (%s)' can't be established.\n" |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 609 | "%s key fingerprint is %s.\n" |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 610 | "Are you sure you want to continue connecting (yes/no)? ", |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 611 | host, ip, type, key_fingerprint(host_key)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 612 | if (!read_yes_or_no(prompt, -1)) |
| 613 | fatal("Aborted by user!\n"); |
| 614 | } |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 615 | if (options.check_host_ip && ip_status == HOST_NEW) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 616 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); |
| 617 | hostp = hostline; |
| 618 | } else |
| 619 | hostp = host; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 620 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 621 | /* 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] | 622 | if (!add_host_to_hostfile(user_hostfile, hostp, host_key)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 623 | 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] | 624 | user_hostfile); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 625 | else |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 626 | log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.", |
| 627 | hostp, type); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 628 | break; |
| 629 | case HOST_CHANGED: |
| 630 | if (options.check_host_ip && host_ip_differ) { |
| 631 | char *msg; |
| 632 | if (ip_status == HOST_NEW) |
| 633 | msg = "is unknown"; |
| 634 | else if (ip_status == HOST_OK) |
| 635 | msg = "is unchanged"; |
| 636 | else |
| 637 | msg = "has a different value"; |
| 638 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| 639 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); |
| 640 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 641 | error("The %s host key for %s has changed,", type, host); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 642 | error("and the key for the according IP address %s", ip); |
| 643 | error("%s. This could either mean that", msg); |
| 644 | error("DNS SPOOFING is happening or the IP address for the host"); |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 645 | error("and its host key have changed at the same time."); |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 646 | if (ip_status != HOST_NEW) |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 647 | error("Offending key for IP in %s:%d", ip_file, ip_line); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 648 | } |
| 649 | /* The host key has changed. */ |
| 650 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
Damien Miller | f039bad | 1999-12-21 20:57:20 +1100 | [diff] [blame] | 651 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 652 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| 653 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); |
| 654 | 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] | 655 | 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] | 656 | error("The fingerprint for the %s key sent by the remote host is\n%s.", |
| 657 | type, key_fingerprint(host_key)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 658 | error("Please contact your system administrator."); |
| 659 | 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] | 660 | user_hostfile); |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 661 | error("Offending key in %s:%d", host_file, host_line); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 662 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 663 | /* |
| 664 | * If strict host key checking is in use, the user will have |
| 665 | * to edit the key manually and we can only abort. |
| 666 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 667 | if (options.strict_host_key_checking) |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 668 | 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] | 669 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 670 | /* |
| 671 | * If strict host key checking has not been requested, allow |
| 672 | * the connection but without password authentication or |
| 673 | * agent forwarding. |
| 674 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 675 | if (options.password_authentication) { |
| 676 | error("Password authentication is disabled to avoid trojan horses."); |
| 677 | options.password_authentication = 0; |
| 678 | } |
| 679 | if (options.forward_agent) { |
| 680 | error("Agent forwarding is disabled to avoid trojan horses."); |
| 681 | options.forward_agent = 0; |
| 682 | } |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 683 | if (options.forward_x11) { |
| 684 | error("X11 forwarding is disabled to avoid trojan horses."); |
| 685 | options.forward_x11 = 0; |
| 686 | } |
| 687 | if (options.num_local_forwards > 0 || options.num_remote_forwards > 0) { |
| 688 | error("Port forwarding is disabled to avoid trojan horses."); |
| 689 | options.num_local_forwards = options.num_remote_forwards = 0; |
| 690 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 691 | /* |
| 692 | * XXX Should permit the user to change to use the new id. |
| 693 | * This could be done by converting the host key to an |
| 694 | * identifying sentence, tell that the host identifies itself |
| 695 | * by that sentence, and ask the user if he/she whishes to |
| 696 | * accept the authentication. |
| 697 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 698 | break; |
| 699 | } |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 700 | |
Ben Lindstrom | 5c1fbab | 2001-01-03 03:51:15 +0000 | [diff] [blame] | 701 | if (options.check_host_ip && host_status != HOST_CHANGED && |
| 702 | ip_status == HOST_CHANGED) { |
| 703 | log("Warning: the %s host key for '%.200s' " |
| 704 | "differs from the key for the IP address '%.30s'", |
| 705 | type, host, ip); |
| 706 | if (host_status == HOST_OK) |
| 707 | log("Matching host key in %s:%d", host_file, host_line); |
| 708 | log("Offending key for IP in %s:%d", ip_file, ip_line); |
| 709 | if (options.strict_host_key_checking == 1) { |
| 710 | fatal("Exiting, you have requested strict checking."); |
| 711 | } else if (options.strict_host_key_checking == 2) { |
| 712 | if (!read_yes_or_no("Continue?", -1)) |
| 713 | fatal("Aborted by user!\n"); |
| 714 | } |
| 715 | } |
| 716 | |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 717 | xfree(ip); |
Damien Miller | a34a28b | 1999-12-14 10:47:15 +1100 | [diff] [blame] | 718 | } |
Damien Miller | 037a0dc | 1999-12-07 15:38:31 +1100 | [diff] [blame] | 719 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 720 | /* |
| 721 | * Starts a dialog with the server, and authenticates the current user on the |
| 722 | * server. This does not need any extra privileges. The basic connection |
| 723 | * to the server must already have been established before this is called. |
| 724 | * If login fails, this function prints an error and never returns. |
| 725 | * This function does not require super-user privileges. |
| 726 | */ |
| 727 | void |
| 728 | ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost, |
| 729 | struct sockaddr *hostaddr, uid_t original_real_uid) |
| 730 | { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 731 | struct passwd *pw; |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 732 | char *host, *cp; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 733 | char *server_user, *local_user; |
| 734 | |
| 735 | /* Get local user name. Use it as server user if no user name was given. */ |
| 736 | pw = getpwuid(original_real_uid); |
| 737 | if (!pw) |
Damien Miller | caf6dd6 | 2000-08-29 11:33:50 +1100 | [diff] [blame] | 738 | fatal("User id %u not found from user database.", original_real_uid); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 739 | local_user = xstrdup(pw->pw_name); |
| 740 | server_user = options.user ? options.user : local_user; |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 741 | |
| 742 | /* Convert the user-supplied hostname into all lowercase. */ |
| 743 | host = xstrdup(orighost); |
| 744 | for (cp = host; *cp; cp++) |
| 745 | if (isupper(*cp)) |
| 746 | *cp = tolower(*cp); |
| 747 | |
| 748 | /* Exchange protocol version identification strings with the server. */ |
| 749 | ssh_exchange_identification(); |
| 750 | |
| 751 | /* Put the connection into non-blocking mode. */ |
| 752 | packet_set_nonblocking(); |
| 753 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 754 | /* key exchange */ |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 755 | /* authenticate user */ |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 756 | if (compat20) { |
| 757 | ssh_kex2(host, hostaddr); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 758 | ssh_userauth2(server_user, host); |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 759 | } else { |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame] | 760 | ssh_kex(host, hostaddr); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 761 | 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] | 762 | } |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 763 | } |