Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.206
1.206 ! grunk 1: /* $OpenBSD: sshconnect.c,v 1.205 2008/06/12 00:03:49 dtucker Exp $ */
1.1 deraadt 2: /*
1.39 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
6: * Code to connect to a remote host, and to perform the client side of the
7: * login (authentication) dialog.
1.78 deraadt 8: *
9: * As far as I am concerned, the code I have written for this software
10: * can be used freely for any purpose. Any derived versions of this
11: * software must be clearly marked as such, and if the derived work is
12: * incompatible with the protocol description in the RFC file, it must be
13: * called by a name other than "ssh" or "Secure Shell".
1.39 deraadt 14: */
1.1 deraadt 15:
1.174 stevesk 16: #include <sys/types.h>
17: #include <sys/wait.h>
1.175 stevesk 18: #include <sys/stat.h>
1.187 stevesk 19: #include <sys/socket.h>
1.195 stevesk 20: #include <sys/time.h>
1.187 stevesk 21:
22: #include <netinet/in.h>
1.172 stevesk 23:
1.176 stevesk 24: #include <ctype.h>
1.190 stevesk 25: #include <errno.h>
1.191 stevesk 26: #include <netdb.h>
1.172 stevesk 27: #include <paths.h>
1.199 deraadt 28: #include <signal.h>
1.188 stevesk 29: #include <pwd.h>
1.198 stevesk 30: #include <stdio.h>
1.196 stevesk 31: #include <stdlib.h>
1.193 stevesk 32: #include <string.h>
1.192 stevesk 33: #include <unistd.h>
1.71 markus 34:
1.199 deraadt 35: #include "xmalloc.h"
1.91 markus 36: #include "ssh.h"
1.1 deraadt 37: #include "rsa.h"
1.59 markus 38: #include "buffer.h"
1.1 deraadt 39: #include "packet.h"
40: #include "uidswap.h"
1.21 markus 41: #include "compat.h"
1.58 markus 42: #include "key.h"
1.71 markus 43: #include "sshconnect.h"
1.58 markus 44: #include "hostfile.h"
1.91 markus 45: #include "log.h"
46: #include "readconf.h"
47: #include "atomicio.h"
48: #include "misc.h"
1.140 jakob 49: #include "dns.h"
1.186 stevesk 50: #include "version.h"
1.140 jakob 51:
1.70 markus 52: char *client_version_string = NULL;
53: char *server_version_string = NULL;
1.59 markus 54:
1.169 stevesk 55: static int matching_host_key_dns = 0;
1.145 jakob 56:
1.124 markus 57: /* import */
1.43 markus 58: extern Options options;
1.50 markus 59: extern char *__progname;
1.124 markus 60: extern uid_t original_real_uid;
61: extern uid_t original_effective_uid;
1.135 djm 62: extern pid_t proxy_command_pid;
1.91 markus 63:
1.132 markus 64: static int show_other_keys(const char *, Key *);
1.150 jakob 65: static void warn_changed_key(Key *);
1.132 markus 66:
1.202 djm 67: static void
68: ms_subtract_diff(struct timeval *start, int *ms)
69: {
70: struct timeval diff, finish;
71:
72: gettimeofday(&finish, NULL);
73: timersub(&finish, start, &diff);
74: *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
75: }
76:
77: static void
78: ms_to_timeval(struct timeval *tv, int ms)
79: {
80: tv->tv_sec = ms / 1000;
81: tv->tv_usec = (ms % 1000) * 1000;
82: }
83:
1.39 deraadt 84: /*
85: * Connect to the given ssh server using a proxy command.
86: */
1.109 itojun 87: static int
1.124 markus 88: ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
1.1 deraadt 89: {
1.164 djm 90: char *command_string, *tmp;
1.38 markus 91: int pin[2], pout[2];
1.69 deraadt 92: pid_t pid;
1.201 djm 93: char *shell, strport[NI_MAXSERV];
94:
95: if ((shell = getenv("SHELL")) == NULL)
96: shell = _PATH_BSHELL;
1.38 markus 97:
98: /* Convert the port number into a string. */
1.49 markus 99: snprintf(strport, sizeof strport, "%hu", port);
1.38 markus 100:
1.135 djm 101: /*
102: * Build the final command string in the buffer by making the
103: * appropriate substitutions to the given proxy command.
104: *
1.154 djm 105: * Use "exec" to avoid "sh -c" processes on some platforms
1.135 djm 106: * (e.g. Solaris)
107: */
1.179 djm 108: xasprintf(&tmp, "exec %s", proxy_command);
1.164 djm 109: command_string = percent_expand(tmp, "h", host,
110: "p", strport, (char *)NULL);
111: xfree(tmp);
1.38 markus 112:
113: /* Create pipes for communicating with the proxy. */
114: if (pipe(pin) < 0 || pipe(pout) < 0)
115: fatal("Could not create pipes to communicate with the proxy: %.100s",
1.118 deraadt 116: strerror(errno));
1.38 markus 117:
118: debug("Executing proxy command: %.500s", command_string);
119:
120: /* Fork and execute the proxy command. */
121: if ((pid = fork()) == 0) {
122: char *argv[10];
123:
124: /* Child. Permanently give up superuser privileges. */
1.184 markus 125: permanently_drop_suid(original_real_uid);
1.38 markus 126:
127: /* Redirect stdin and stdout. */
128: close(pin[1]);
129: if (pin[0] != 0) {
130: if (dup2(pin[0], 0) < 0)
131: perror("dup2 stdin");
132: close(pin[0]);
133: }
134: close(pout[0]);
135: if (dup2(pout[1], 1) < 0)
136: perror("dup2 stdout");
137: /* Cannot be 1 because pin allocated two descriptors. */
138: close(pout[1]);
139:
140: /* Stderr is left as it is so that error messages get
141: printed on the user's terminal. */
1.201 djm 142: argv[0] = shell;
1.38 markus 143: argv[1] = "-c";
144: argv[2] = command_string;
145: argv[3] = NULL;
146:
147: /* Execute the proxy command. Note that we gave up any
148: extra privileges above. */
1.89 markus 149: execv(argv[0], argv);
150: perror(argv[0]);
1.38 markus 151: exit(1);
152: }
153: /* Parent. */
154: if (pid < 0)
155: fatal("fork failed: %.100s", strerror(errno));
1.135 djm 156: else
157: proxy_command_pid = pid; /* save pid to clean up later */
1.38 markus 158:
159: /* Close child side of the descriptors. */
160: close(pin[0]);
161: close(pout[1]);
162:
163: /* Free the command name. */
1.164 djm 164: xfree(command_string);
1.38 markus 165:
166: /* Set the connection file descriptors. */
167: packet_set_connection(pout[0], pin[1]);
1.1 deraadt 168:
1.110 markus 169: /* Indicate OK return */
170: return 0;
1.1 deraadt 171: }
172:
1.39 deraadt 173: /*
174: * Creates a (possibly privileged) socket for use as the ssh connection.
175: */
1.109 itojun 176: static int
1.139 markus 177: ssh_create_socket(int privileged, struct addrinfo *ai)
1.1 deraadt 178: {
1.105 markus 179: int sock, gaierr;
180: struct addrinfo hints, *res;
1.1 deraadt 181:
1.40 markus 182: /*
183: * If we are running as root and want to connect to a privileged
184: * port, bind our own socket to a privileged port.
185: */
1.38 markus 186: if (privileged) {
187: int p = IPPORT_RESERVED - 1;
1.124 markus 188: PRIV_START;
1.139 markus 189: sock = rresvport_af(&p, ai->ai_family);
1.124 markus 190: PRIV_END;
1.38 markus 191: if (sock < 0)
1.139 markus 192: error("rresvport: af=%d %.100s", ai->ai_family,
193: strerror(errno));
1.55 markus 194: else
195: debug("Allocated local port %d.", p);
1.105 markus 196: return sock;
197: }
1.139 markus 198: sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1.105 markus 199: if (sock < 0)
200: error("socket: %.100s", strerror(errno));
201:
202: /* Bind the socket to an alternative local IP address */
203: if (options.bind_address == NULL)
204: return sock;
205:
206: memset(&hints, 0, sizeof(hints));
1.139 markus 207: hints.ai_family = ai->ai_family;
208: hints.ai_socktype = ai->ai_socktype;
209: hints.ai_protocol = ai->ai_protocol;
1.105 markus 210: hints.ai_flags = AI_PASSIVE;
1.205 dtucker 211: gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
1.105 markus 212: if (gaierr) {
213: error("getaddrinfo: %s: %s", options.bind_address,
1.203 dtucker 214: ssh_gai_strerror(gaierr));
1.105 markus 215: close(sock);
216: return -1;
217: }
218: if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
219: error("bind: %s: %s", options.bind_address, strerror(errno));
220: close(sock);
221: freeaddrinfo(res);
222: return -1;
1.38 markus 223: }
1.105 markus 224: freeaddrinfo(res);
1.38 markus 225: return sock;
1.1 deraadt 226: }
227:
1.141 djm 228: static int
229: timeout_connect(int sockfd, const struct sockaddr *serv_addr,
1.202 djm 230: socklen_t addrlen, int *timeoutp)
1.141 djm 231: {
232: fd_set *fdset;
1.202 djm 233: struct timeval tv, t_start;
1.141 djm 234: socklen_t optlen;
1.179 djm 235: int optval, rc, result = -1;
1.141 djm 236:
1.202 djm 237: gettimeofday(&t_start, NULL);
238:
239: if (*timeoutp <= 0) {
240: result = connect(sockfd, serv_addr, addrlen);
241: goto done;
242: }
1.141 djm 243:
1.156 djm 244: set_nonblock(sockfd);
1.141 djm 245: rc = connect(sockfd, serv_addr, addrlen);
1.156 djm 246: if (rc == 0) {
247: unset_nonblock(sockfd);
1.202 djm 248: result = 0;
249: goto done;
250: }
251: if (errno != EINPROGRESS) {
252: result = -1;
253: goto done;
1.156 djm 254: }
1.141 djm 255:
1.179 djm 256: fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
257: sizeof(fd_mask));
1.141 djm 258: FD_SET(sockfd, fdset);
1.202 djm 259: ms_to_timeval(&tv, *timeoutp);
1.141 djm 260:
1.162 deraadt 261: for (;;) {
1.141 djm 262: rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
263: if (rc != -1 || errno != EINTR)
264: break;
265: }
266:
1.162 deraadt 267: switch (rc) {
1.141 djm 268: case 0:
269: /* Timed out */
270: errno = ETIMEDOUT;
1.142 djm 271: break;
1.141 djm 272: case -1:
273: /* Select error */
1.154 djm 274: debug("select: %s", strerror(errno));
1.142 djm 275: break;
1.141 djm 276: case 1:
277: /* Completed or failed */
278: optval = 0;
279: optlen = sizeof(optval);
1.154 djm 280: if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
1.148 markus 281: &optlen) == -1) {
1.154 djm 282: debug("getsockopt: %s", strerror(errno));
1.142 djm 283: break;
1.148 markus 284: }
1.141 djm 285: if (optval != 0) {
286: errno = optval;
1.142 djm 287: break;
1.141 djm 288: }
1.142 djm 289: result = 0;
1.156 djm 290: unset_nonblock(sockfd);
1.141 djm 291: break;
292: default:
293: /* Should not occur */
294: fatal("Bogus return (%d) from select()", rc);
295: }
296:
1.142 djm 297: xfree(fdset);
1.202 djm 298:
299: done:
300: if (result == 0 && *timeoutp > 0) {
301: ms_subtract_diff(&t_start, timeoutp);
302: if (*timeoutp <= 0) {
303: errno = ETIMEDOUT;
304: result = -1;
305: }
306: }
307:
1.142 djm 308: return (result);
1.141 djm 309: }
310:
1.39 deraadt 311: /*
1.49 markus 312: * Opens a TCP/IP connection to the remote server on the given host.
313: * The address of the remote host will be returned in hostaddr.
1.124 markus 314: * If port is 0, the default port will be used. If needpriv is true,
1.39 deraadt 315: * a privileged port will be allocated to make the connection.
1.124 markus 316: * This requires super-user privileges if needpriv is true.
1.39 deraadt 317: * Connection_attempts specifies the maximum number of tries (one per
318: * second). If proxy_command is non-NULL, it specifies the command (with %h
319: * and %p substituted for host and port, respectively) to use to contact
320: * the daemon.
321: */
1.38 markus 322: int
1.49 markus 323: ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
1.202 djm 324: u_short port, int family, int connection_attempts, int *timeout_ms,
325: int want_keepalive, int needpriv, const char *proxy_command)
1.1 deraadt 326: {
1.90 markus 327: int gaierr;
328: int on = 1;
1.49 markus 329: int sock = -1, attempt;
1.90 markus 330: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.49 markus 331: struct addrinfo hints, *ai, *aitop;
1.38 markus 332:
1.136 markus 333: debug2("ssh_connect: needpriv %d", needpriv);
1.38 markus 334:
335: /* If a proxy command is given, connect using it. */
336: if (proxy_command != NULL)
1.124 markus 337: return ssh_proxy_connect(host, port, proxy_command);
1.38 markus 338:
339: /* No proxy command. */
340:
1.49 markus 341: memset(&hints, 0, sizeof(hints));
1.115 markus 342: hints.ai_family = family;
1.49 markus 343: hints.ai_socktype = SOCK_STREAM;
1.126 deraadt 344: snprintf(strport, sizeof strport, "%u", port);
1.49 markus 345: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
1.203 dtucker 346: fatal("%s: Could not resolve hostname %.100s: %s", __progname,
347: host, ssh_gai_strerror(gaierr));
1.38 markus 348:
1.181 markus 349: for (attempt = 0; attempt < connection_attempts; attempt++) {
1.200 markus 350: if (attempt > 0) {
351: /* Sleep a moment before retrying. */
352: sleep(1);
1.38 markus 353: debug("Trying again...");
1.200 markus 354: }
1.181 markus 355: /*
356: * Loop through addresses for this host, and try each one in
357: * sequence until the connection succeeds.
358: */
1.49 markus 359: for (ai = aitop; ai; ai = ai->ai_next) {
360: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
361: continue;
362: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
363: ntop, sizeof(ntop), strport, sizeof(strport),
364: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
365: error("ssh_connect: getnameinfo failed");
366: continue;
367: }
368: debug("Connecting to %.200s [%.100s] port %s.",
369: host, ntop, strport);
370:
371: /* Create a socket for connecting. */
1.139 markus 372: sock = ssh_create_socket(needpriv, ai);
1.49 markus 373: if (sock < 0)
1.110 markus 374: /* Any error is already output */
1.49 markus 375: continue;
376:
1.141 djm 377: if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
1.202 djm 378: timeout_ms) >= 0) {
1.49 markus 379: /* Successful connection. */
1.102 markus 380: memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
1.38 markus 381: break;
1.49 markus 382: } else {
1.131 itojun 383: debug("connect to address %s port %s: %s",
384: ntop, strport, strerror(errno));
1.38 markus 385: close(sock);
1.181 markus 386: sock = -1;
1.38 markus 387: }
388: }
1.181 markus 389: if (sock != -1)
1.49 markus 390: break; /* Successful connection. */
1.38 markus 391: }
1.49 markus 392:
393: freeaddrinfo(aitop);
394:
1.38 markus 395: /* Return failure if we didn't get a successful connection. */
1.181 markus 396: if (sock == -1) {
1.159 markus 397: error("ssh: connect to host %s port %s: %s",
1.130 itojun 398: host, strport, strerror(errno));
1.159 markus 399: return (-1);
1.130 itojun 400: }
1.38 markus 401:
402: debug("Connection established.");
1.90 markus 403:
1.155 markus 404: /* Set SO_KEEPALIVE if requested. */
1.202 djm 405: if (want_keepalive &&
1.90 markus 406: setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
407: sizeof(on)) < 0)
408: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.38 markus 409:
410: /* Set the connection. */
411: packet_set_connection(sock, sock);
1.1 deraadt 412:
1.110 markus 413: return 0;
1.59 markus 414: }
415:
1.43 markus 416: /*
1.39 deraadt 417: * Waits for the server identification string, and sends our own
418: * identification string.
419: */
1.109 itojun 420: static void
1.202 djm 421: ssh_exchange_identification(int timeout_ms)
1.1 deraadt 422: {
1.38 markus 423: char buf[256], remote_version[256]; /* must be same size! */
1.165 djm 424: int remote_major, remote_minor, mismatch;
1.38 markus 425: int connection_in = packet_get_connection_in();
426: int connection_out = packet_get_connection_out();
1.93 stevesk 427: int minor1 = PROTOCOL_MINOR_1;
1.185 djm 428: u_int i, n;
1.202 djm 429: size_t len;
430: int fdsetsz, remaining, rc;
431: struct timeval t_start, t_remaining;
432: fd_set *fdset;
433:
434: fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
435: fdset = xcalloc(1, fdsetsz);
1.38 markus 436:
1.163 avsm 437: /* Read other side's version identification. */
1.202 djm 438: remaining = timeout_ms;
1.185 djm 439: for (n = 0;;) {
1.75 markus 440: for (i = 0; i < sizeof(buf) - 1; i++) {
1.202 djm 441: if (timeout_ms > 0) {
442: gettimeofday(&t_start, NULL);
443: ms_to_timeval(&t_remaining, remaining);
444: FD_SET(connection_in, fdset);
445: rc = select(connection_in + 1, fdset, NULL,
446: fdset, &t_remaining);
447: ms_subtract_diff(&t_start, &remaining);
448: if (rc == 0 || remaining <= 0)
449: fatal("Connection timed out during "
450: "banner exchange");
451: if (rc == -1) {
452: if (errno == EINTR)
453: continue;
454: fatal("ssh_exchange_identification: "
455: "select: %s", strerror(errno));
456: }
457: }
458:
459: len = atomicio(read, connection_in, &buf[i], 1);
1.163 avsm 460:
1.167 djm 461: if (len != 1 && errno == EPIPE)
1.202 djm 462: fatal("ssh_exchange_identification: "
463: "Connection closed by remote host");
1.163 avsm 464: else if (len != 1)
1.202 djm 465: fatal("ssh_exchange_identification: "
466: "read: %.100s", strerror(errno));
1.75 markus 467: if (buf[i] == '\r') {
468: buf[i] = '\n';
469: buf[i + 1] = 0;
470: continue; /**XXX wait for \n */
471: }
472: if (buf[i] == '\n') {
473: buf[i + 1] = 0;
474: break;
475: }
1.185 djm 476: if (++n > 65536)
1.202 djm 477: fatal("ssh_exchange_identification: "
478: "No banner received");
1.38 markus 479: }
1.75 markus 480: buf[sizeof(buf) - 1] = 0;
1.76 markus 481: if (strncmp(buf, "SSH-", 4) == 0)
1.38 markus 482: break;
1.75 markus 483: debug("ssh_exchange_identification: %s", buf);
1.38 markus 484: }
1.59 markus 485: server_version_string = xstrdup(buf);
1.202 djm 486: xfree(fdset);
1.38 markus 487:
1.40 markus 488: /*
489: * Check that the versions match. In future this might accept
490: * several versions and set appropriate flags to handle them.
491: */
1.59 markus 492: if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
493: &remote_major, &remote_minor, remote_version) != 3)
1.38 markus 494: fatal("Bad remote protocol version identification: '%.100s'", buf);
495: debug("Remote protocol version %d.%d, remote software version %.100s",
1.118 deraadt 496: remote_major, remote_minor, remote_version);
1.38 markus 497:
1.59 markus 498: compat_datafellows(remote_version);
1.64 markus 499: mismatch = 0;
1.59 markus 500:
1.116 deraadt 501: switch (remote_major) {
1.64 markus 502: case 1:
503: if (remote_minor == 99 &&
504: (options.protocol & SSH_PROTO_2) &&
505: !(options.protocol & SSH_PROTO_1_PREFERRED)) {
506: enable_compat20();
507: break;
508: }
509: if (!(options.protocol & SSH_PROTO_1)) {
510: mismatch = 1;
511: break;
512: }
513: if (remote_minor < 3) {
514: fatal("Remote machine has too old SSH software version.");
1.81 markus 515: } else if (remote_minor == 3 || remote_minor == 4) {
1.64 markus 516: /* We speak 1.3, too. */
517: enable_compat13();
1.81 markus 518: minor1 = 3;
1.64 markus 519: if (options.forward_agent) {
1.138 itojun 520: logit("Agent forwarding disabled for protocol 1.3");
1.64 markus 521: options.forward_agent = 0;
522: }
523: }
524: break;
525: case 2:
526: if (options.protocol & SSH_PROTO_2) {
527: enable_compat20();
528: break;
1.38 markus 529: }
1.64 markus 530: /* FALLTHROUGH */
1.68 markus 531: default:
1.64 markus 532: mismatch = 1;
533: break;
1.38 markus 534: }
1.64 markus 535: if (mismatch)
1.38 markus 536: fatal("Protocol major versions differ: %d vs. %d",
1.64 markus 537: (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
538: remote_major);
1.38 markus 539: /* Send our own protocol version identification. */
540: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
1.64 markus 541: compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
1.81 markus 542: compat20 ? PROTOCOL_MINOR_2 : minor1,
1.59 markus 543: SSH_VERSION);
1.146 deraadt 544: if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
1.38 markus 545: fatal("write: %.100s", strerror(errno));
1.59 markus 546: client_version_string = xstrdup(buf);
547: chop(client_version_string);
548: chop(server_version_string);
549: debug("Local version string %.100s", client_version_string);
1.1 deraadt 550: }
551:
1.96 markus 552: /* defaults to 'no' */
1.109 itojun 553: static int
1.112 markus 554: confirm(const char *prompt)
1.1 deraadt 555: {
1.119 markus 556: const char *msg, *again = "Please type 'yes' or 'no': ";
557: char *p;
558: int ret = -1;
1.96 markus 559:
560: if (options.batch_mode)
561: return 0;
1.119 markus 562: for (msg = prompt;;msg = again) {
563: p = read_passphrase(msg, RP_ECHO);
564: if (p == NULL ||
565: (p[0] == '\0') || (p[0] == '\n') ||
566: strncasecmp(p, "no", 2) == 0)
567: ret = 0;
1.127 markus 568: if (p && strncasecmp(p, "yes", 3) == 0)
1.119 markus 569: ret = 1;
570: if (p)
571: xfree(p);
572: if (ret != -1)
573: return ret;
1.1 deraadt 574: }
575: }
576:
1.39 deraadt 577: /*
1.108 markus 578: * check whether the supplied host key is valid, return -1 if the key
579: * is not valid. the user_hostfile will not be updated if 'readonly' is true.
1.39 deraadt 580: */
1.197 dtucker 581: #define RDRW 0
582: #define RDONLY 1
583: #define ROQUIET 2
1.109 itojun 584: static int
1.197 dtucker 585: check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
586: Key *host_key, int readonly, const char *user_hostfile,
587: const char *system_hostfile)
1.1 deraadt 588: {
1.58 markus 589: Key *file_key;
1.152 jakob 590: const char *type = key_type(host_key);
1.189 dtucker 591: char *ip = NULL, *host = NULL;
1.204 grunk 592: char hostline[1000], *hostp, *fp, *ra;
1.38 markus 593: HostStatus host_status;
594: HostStatus ip_status;
1.161 djm 595: int r, local = 0, host_ip_differ = 0;
1.49 markus 596: char ntop[NI_MAXHOST];
1.119 markus 597: char msg[1024];
1.145 jakob 598: int len, host_line, ip_line;
1.85 markus 599: const char *host_file = NULL, *ip_file = NULL;
1.206 ! grunk 600: int display_randomart;
1.49 markus 601:
602: /*
603: * Force accepting of the host key for loopback/localhost. The
604: * problem is that if the home directory is NFS-mounted to multiple
605: * machines, localhost will refer to a different machine in each of
606: * them, and the user will get bogus HOST_CHANGED warnings. This
607: * essentially disables host authentication for localhost; however,
608: * this is probably not a real problem.
609: */
1.70 markus 610: /** hostaddr == 0! */
1.49 markus 611: switch (hostaddr->sa_family) {
612: case AF_INET:
1.108 markus 613: local = (ntohl(((struct sockaddr_in *)hostaddr)->
1.168 djm 614: sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
1.49 markus 615: break;
616: case AF_INET6:
1.108 markus 617: local = IN6_IS_ADDR_LOOPBACK(
618: &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
1.49 markus 619: break;
620: default:
621: local = 0;
622: break;
623: }
1.111 markus 624: if (options.no_host_authentication_for_localhost == 1 && local &&
625: options.host_key_alias == NULL) {
1.88 markus 626: debug("Forcing accepting of host key for "
627: "loopback/localhost.");
1.108 markus 628: return 0;
1.49 markus 629: }
1.42 markus 630:
631: /*
1.88 markus 632: * We don't have the remote ip-address for connections
633: * using a proxy command
1.42 markus 634: */
1.84 markus 635: if (options.proxy_command == NULL) {
636: if (getnameinfo(hostaddr, hostaddr->sa_len, ntop, sizeof(ntop),
1.86 markus 637: NULL, 0, NI_NUMERICHOST) != 0)
1.84 markus 638: fatal("check_host_key: getnameinfo failed");
1.197 dtucker 639: ip = put_host_port(ntop, port);
1.84 markus 640: } else {
641: ip = xstrdup("<no hostip for proxy command>");
1.86 markus 642: }
1.206 ! grunk 643:
! 644: /*
! 645: * check_host_ip may be set to zero in the next step, so if it
! 646: * conveys a request to display the random art, save it away.
! 647: */
! 648: display_randomart = (options.check_host_ip == SSHCTL_CHECKHOSTIP_FPR);
! 649:
1.88 markus 650: /*
651: * Turn off check_host_ip if the connection is to localhost, via proxy
652: * command or if we don't have a hostname to compare with
653: */
1.189 dtucker 654: if (options.check_host_ip && (local ||
655: strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88 markus 656: options.check_host_ip = 0;
1.86 markus 657:
658: /*
1.189 dtucker 659: * Allow the user to record the key under a different name or
660: * differentiate a non-standard port. This is useful for ssh
661: * tunneling over forwarded connections or if you run multiple
662: * sshd's on different ports on the same machine.
1.86 markus 663: */
664: if (options.host_key_alias != NULL) {
1.189 dtucker 665: host = xstrdup(options.host_key_alias);
1.86 markus 666: debug("using hostkeyalias: %s", host);
1.189 dtucker 667: } else {
1.197 dtucker 668: host = put_host_port(hostname, port);
1.84 markus 669: }
1.38 markus 670:
1.46 markus 671: /*
672: * Store the host key from the known host file in here so that we can
673: * compare it with the key for the IP address.
674: */
1.58 markus 675: file_key = key_new(host_key->type);
1.38 markus 676:
1.40 markus 677: /*
1.170 djm 678: * Check if the host key is present in the user's list of known
1.40 markus 679: * hosts or in the systemwide list.
680: */
1.85 markus 681: host_file = user_hostfile;
1.108 markus 682: host_status = check_host_in_hostfile(host_file, host, host_key,
1.118 deraadt 683: file_key, &host_line);
1.85 markus 684: if (host_status == HOST_NEW) {
685: host_file = system_hostfile;
1.108 markus 686: host_status = check_host_in_hostfile(host_file, host, host_key,
687: file_key, &host_line);
1.85 markus 688: }
1.40 markus 689: /*
690: * Also perform check for the ip address, skip the check if we are
691: * localhost or the hostname was an ip address to begin with
692: */
1.88 markus 693: if (options.check_host_ip) {
1.58 markus 694: Key *ip_key = key_new(host_key->type);
1.38 markus 695:
1.85 markus 696: ip_file = user_hostfile;
1.108 markus 697: ip_status = check_host_in_hostfile(ip_file, ip, host_key,
698: ip_key, &ip_line);
1.85 markus 699: if (ip_status == HOST_NEW) {
700: ip_file = system_hostfile;
1.108 markus 701: ip_status = check_host_in_hostfile(ip_file, ip,
702: host_key, ip_key, &ip_line);
1.85 markus 703: }
1.38 markus 704: if (host_status == HOST_CHANGED &&
1.58 markus 705: (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
1.38 markus 706: host_ip_differ = 1;
707:
1.58 markus 708: key_free(ip_key);
1.38 markus 709: } else
710: ip_status = host_status;
711:
1.58 markus 712: key_free(file_key);
1.38 markus 713:
714: switch (host_status) {
715: case HOST_OK:
716: /* The host is known and the key matches. */
1.72 markus 717: debug("Host '%.200s' is known and matches the %s host key.",
718: host, type);
1.85 markus 719: debug("Found key in %s:%d", host_file, host_line);
1.88 markus 720: if (options.check_host_ip && ip_status == HOST_NEW) {
1.108 markus 721: if (readonly)
1.138 itojun 722: logit("%s host key for IP address "
1.108 markus 723: "'%.128s' not in list of known hosts.",
724: type, ip);
725: else if (!add_host_to_hostfile(user_hostfile, ip,
1.160 djm 726: host_key, options.hash_known_hosts))
1.138 itojun 727: logit("Failed to add the %s host key for IP "
1.108 markus 728: "address '%.128s' to the list of known "
729: "hosts (%.30s).", type, ip, user_hostfile);
1.88 markus 730: else
1.138 itojun 731: logit("Warning: Permanently added the %s host "
1.108 markus 732: "key for IP address '%.128s' to the list "
733: "of known hosts.", type, ip);
1.206 ! grunk 734: } else if (display_randomart) {
1.204 grunk 735: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
736: ra = key_fingerprint(host_key, SSH_FP_MD5,
737: SSH_FP_RANDOMART);
738: logit("Host key fingerprint is %s\n%s\n", fp, ra);
739: xfree(ra);
740: xfree(fp);
1.38 markus 741: }
742: break;
743: case HOST_NEW:
1.197 dtucker 744: if (options.host_key_alias == NULL && port != 0 &&
745: port != SSH_DEFAULT_PORT) {
746: debug("checking without port identifier");
747: if (check_host_key(hostname, hostaddr, 0, host_key, 2,
748: user_hostfile, system_hostfile) == 0) {
749: debug("found matching key w/out port");
750: break;
751: }
752: }
1.108 markus 753: if (readonly)
754: goto fail;
1.38 markus 755: /* The host is new. */
756: if (options.strict_host_key_checking == 1) {
1.108 markus 757: /*
758: * User has requested strict host key checking. We
759: * will not add the host key automatically. The only
760: * alternative left is to abort.
761: */
762: error("No %s host key is known for %.200s and you "
763: "have requested strict checking.", type, host);
764: goto fail;
1.38 markus 765: } else if (options.strict_host_key_checking == 2) {
1.145 jakob 766: char msg1[1024], msg2[1024];
767:
768: if (show_other_keys(host, host_key))
769: snprintf(msg1, sizeof(msg1),
1.168 djm 770: "\nbut keys of different type are already"
771: " known for this host.");
1.145 jakob 772: else
773: snprintf(msg1, sizeof(msg1), ".");
1.38 markus 774: /* The default */
1.100 markus 775: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 776: ra = key_fingerprint(host_key, SSH_FP_MD5,
777: SSH_FP_RANDOMART);
1.145 jakob 778: msg2[0] = '\0';
779: if (options.verify_host_key_dns) {
1.153 jakob 780: if (matching_host_key_dns)
1.145 jakob 781: snprintf(msg2, sizeof(msg2),
782: "Matching host key fingerprint"
783: " found in DNS.\n");
784: else
785: snprintf(msg2, sizeof(msg2),
786: "No matching host key fingerprint"
787: " found in DNS.\n");
788: }
1.119 markus 789: snprintf(msg, sizeof(msg),
1.108 markus 790: "The authenticity of host '%.200s (%s)' can't be "
1.132 markus 791: "established%s\n"
1.204 grunk 792: "%s key fingerprint is %s.\n%s\n%s"
1.108 markus 793: "Are you sure you want to continue connecting "
1.132 markus 794: "(yes/no)? ",
1.204 grunk 795: host, ip, msg1, type, fp, ra, msg2);
796: xfree(ra);
1.100 markus 797: xfree(fp);
1.119 markus 798: if (!confirm(msg))
1.108 markus 799: goto fail;
1.38 markus 800: }
1.161 djm 801: /*
802: * If not in strict mode, add the key automatically to the
803: * local known_hosts file.
804: */
1.88 markus 805: if (options.check_host_ip && ip_status == HOST_NEW) {
1.161 djm 806: snprintf(hostline, sizeof(hostline), "%s,%s",
807: host, ip);
1.38 markus 808: hostp = hostline;
1.161 djm 809: if (options.hash_known_hosts) {
810: /* Add hash of host and IP separately */
811: r = add_host_to_hostfile(user_hostfile, host,
812: host_key, options.hash_known_hosts) &&
813: add_host_to_hostfile(user_hostfile, ip,
814: host_key, options.hash_known_hosts);
815: } else {
816: /* Add unhashed "host,ip" */
817: r = add_host_to_hostfile(user_hostfile,
818: hostline, host_key,
819: options.hash_known_hosts);
820: }
821: } else {
822: r = add_host_to_hostfile(user_hostfile, host, host_key,
823: options.hash_known_hosts);
1.38 markus 824: hostp = host;
1.161 djm 825: }
1.38 markus 826:
1.161 djm 827: if (!r)
1.138 itojun 828: logit("Failed to add the host to the list of known "
1.108 markus 829: "hosts (%.500s).", user_hostfile);
1.38 markus 830: else
1.138 itojun 831: logit("Warning: Permanently added '%.200s' (%s) to the "
1.108 markus 832: "list of known hosts.", hostp, type);
1.38 markus 833: break;
834: case HOST_CHANGED:
1.197 dtucker 835: if (readonly == ROQUIET)
836: goto fail;
1.38 markus 837: if (options.check_host_ip && host_ip_differ) {
1.158 avsm 838: char *key_msg;
1.38 markus 839: if (ip_status == HOST_NEW)
1.158 avsm 840: key_msg = "is unknown";
1.38 markus 841: else if (ip_status == HOST_OK)
1.158 avsm 842: key_msg = "is unchanged";
1.38 markus 843: else
1.158 avsm 844: key_msg = "has a different value";
1.38 markus 845: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
846: error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
847: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72 markus 848: error("The %s host key for %s has changed,", type, host);
1.38 markus 849: error("and the key for the according IP address %s", ip);
1.158 avsm 850: error("%s. This could either mean that", key_msg);
1.38 markus 851: error("DNS SPOOFING is happening or the IP address for the host");
1.85 markus 852: error("and its host key have changed at the same time.");
1.88 markus 853: if (ip_status != HOST_NEW)
1.85 markus 854: error("Offending key for IP in %s:%d", ip_file, ip_line);
1.38 markus 855: }
856: /* The host key has changed. */
1.150 jakob 857: warn_changed_key(host_key);
1.38 markus 858: error("Add correct host key in %.100s to get rid of this message.",
1.87 markus 859: user_hostfile);
1.85 markus 860: error("Offending key in %s:%d", host_file, host_line);
1.38 markus 861:
1.40 markus 862: /*
863: * If strict host key checking is in use, the user will have
864: * to edit the key manually and we can only abort.
865: */
1.108 markus 866: if (options.strict_host_key_checking) {
867: error("%s host key for %.200s has changed and you have "
868: "requested strict checking.", type, host);
869: goto fail;
870: }
1.38 markus 871:
1.40 markus 872: /*
873: * If strict host key checking has not been requested, allow
1.144 djm 874: * the connection but without MITM-able authentication or
1.194 stevesk 875: * forwarding.
1.40 markus 876: */
1.38 markus 877: if (options.password_authentication) {
1.108 markus 878: error("Password authentication is disabled to avoid "
879: "man-in-the-middle attacks.");
1.38 markus 880: options.password_authentication = 0;
1.144 djm 881: }
882: if (options.kbd_interactive_authentication) {
883: error("Keyboard-interactive authentication is disabled"
884: " to avoid man-in-the-middle attacks.");
885: options.kbd_interactive_authentication = 0;
886: options.challenge_response_authentication = 0;
887: }
888: if (options.challenge_response_authentication) {
889: error("Challenge/response authentication is disabled"
890: " to avoid man-in-the-middle attacks.");
891: options.challenge_response_authentication = 0;
1.38 markus 892: }
893: if (options.forward_agent) {
1.108 markus 894: error("Agent forwarding is disabled to avoid "
895: "man-in-the-middle attacks.");
1.38 markus 896: options.forward_agent = 0;
1.83 markus 897: }
898: if (options.forward_x11) {
1.108 markus 899: error("X11 forwarding is disabled to avoid "
900: "man-in-the-middle attacks.");
1.83 markus 901: options.forward_x11 = 0;
902: }
1.108 markus 903: if (options.num_local_forwards > 0 ||
904: options.num_remote_forwards > 0) {
905: error("Port forwarding is disabled to avoid "
906: "man-in-the-middle attacks.");
907: options.num_local_forwards =
1.118 deraadt 908: options.num_remote_forwards = 0;
1.194 stevesk 909: }
910: if (options.tun_open != SSH_TUNMODE_NO) {
911: error("Tunnel forwarding is disabled to avoid "
912: "man-in-the-middle attacks.");
913: options.tun_open = SSH_TUNMODE_NO;
1.38 markus 914: }
1.40 markus 915: /*
916: * XXX Should permit the user to change to use the new id.
917: * This could be done by converting the host key to an
918: * identifying sentence, tell that the host identifies itself
919: * by that sentence, and ask the user if he/she whishes to
920: * accept the authentication.
921: */
1.38 markus 922: break;
1.132 markus 923: case HOST_FOUND:
924: fatal("internal error");
925: break;
1.88 markus 926: }
927:
928: if (options.check_host_ip && host_status != HOST_CHANGED &&
929: ip_status == HOST_CHANGED) {
1.119 markus 930: snprintf(msg, sizeof(msg),
931: "Warning: the %s host key for '%.200s' "
932: "differs from the key for the IP address '%.128s'"
933: "\nOffending key for IP in %s:%d",
934: type, host, ip, ip_file, ip_line);
935: if (host_status == HOST_OK) {
936: len = strlen(msg);
937: snprintf(msg + len, sizeof(msg) - len,
938: "\nMatching host key in %s:%d",
1.125 deraadt 939: host_file, host_line);
1.119 markus 940: }
1.88 markus 941: if (options.strict_host_key_checking == 1) {
1.143 djm 942: logit("%s", msg);
1.108 markus 943: error("Exiting, you have requested strict checking.");
944: goto fail;
1.88 markus 945: } else if (options.strict_host_key_checking == 2) {
1.119 markus 946: strlcat(msg, "\nAre you sure you want "
947: "to continue connecting (yes/no)? ", sizeof(msg));
948: if (!confirm(msg))
1.108 markus 949: goto fail;
1.119 markus 950: } else {
1.143 djm 951: logit("%s", msg);
1.88 markus 952: }
1.38 markus 953: }
1.82 provos 954:
955: xfree(ip);
1.189 dtucker 956: xfree(host);
1.108 markus 957: return 0;
958:
959: fail:
960: xfree(ip);
1.189 dtucker 961: xfree(host);
1.108 markus 962: return -1;
963: }
964:
1.140 jakob 965: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108 markus 966: int
967: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
968: {
969: struct stat st;
1.153 jakob 970: int flags = 0;
1.140 jakob 971:
1.153 jakob 972: if (options.verify_host_key_dns &&
973: verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
974:
975: if (flags & DNS_VERIFY_FOUND) {
976:
977: if (options.verify_host_key_dns == 1 &&
978: flags & DNS_VERIFY_MATCH &&
979: flags & DNS_VERIFY_SECURE)
980: return 0;
981:
982: if (flags & DNS_VERIFY_MATCH) {
983: matching_host_key_dns = 1;
984: } else {
985: warn_changed_key(host_key);
986: error("Update the SSHFP RR in DNS with the new "
987: "host key to get rid of this message.");
988: }
1.140 jakob 989: }
990: }
1.108 markus 991:
992: /* return ok if the key can be found in an old keyfile */
993: if (stat(options.system_hostfile2, &st) == 0 ||
994: stat(options.user_hostfile2, &st) == 0) {
1.197 dtucker 995: if (check_host_key(host, hostaddr, options.port, host_key,
996: RDONLY, options.user_hostfile2,
997: options.system_hostfile2) == 0)
1.108 markus 998: return 0;
999: }
1.197 dtucker 1000: return check_host_key(host, hostaddr, options.port, host_key,
1001: RDRW, options.user_hostfile, options.system_hostfile);
1.51 markus 1002: }
1.70 markus 1003:
1.51 markus 1004: /*
1005: * Starts a dialog with the server, and authenticates the current user on the
1006: * server. This does not need any extra privileges. The basic connection
1007: * to the server must already have been established before this is called.
1008: * If login fails, this function prints an error and never returns.
1009: * This function does not require super-user privileges.
1010: */
1011: void
1.120 markus 1012: ssh_login(Sensitive *sensitive, const char *orighost,
1.202 djm 1013: struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms)
1.51 markus 1014: {
1015: char *host, *cp;
1.70 markus 1016: char *server_user, *local_user;
1017:
1018: local_user = xstrdup(pw->pw_name);
1019: server_user = options.user ? options.user : local_user;
1.51 markus 1020:
1021: /* Convert the user-supplied hostname into all lowercase. */
1022: host = xstrdup(orighost);
1023: for (cp = host; *cp; cp++)
1024: if (isupper(*cp))
1.178 deraadt 1025: *cp = (char)tolower(*cp);
1.51 markus 1026:
1027: /* Exchange protocol version identification strings with the server. */
1.202 djm 1028: ssh_exchange_identification(timeout_ms);
1.51 markus 1029:
1030: /* Put the connection into non-blocking mode. */
1031: packet_set_nonblocking();
1032:
1033: /* key exchange */
1034: /* authenticate user */
1.59 markus 1035: if (compat20) {
1036: ssh_kex2(host, hostaddr);
1.120 markus 1037: ssh_userauth2(local_user, server_user, host, sensitive);
1.59 markus 1038: } else {
1039: ssh_kex(host, hostaddr);
1.120 markus 1040: ssh_userauth1(local_user, server_user, host, sensitive);
1.59 markus 1041: }
1.182 markus 1042: xfree(local_user);
1.97 markus 1043: }
1044:
1045: void
1046: ssh_put_password(char *password)
1047: {
1048: int size;
1049: char *padded;
1050:
1.99 deraadt 1051: if (datafellows & SSH_BUG_PASSWORDPAD) {
1.107 markus 1052: packet_put_cstring(password);
1.99 deraadt 1053: return;
1054: }
1.97 markus 1055: size = roundup(strlen(password) + 1, 32);
1.179 djm 1056: padded = xcalloc(1, size);
1.97 markus 1057: strlcpy(padded, password, size);
1058: packet_put_string(padded, size);
1059: memset(padded, 0, size);
1060: xfree(padded);
1.132 markus 1061: }
1062:
1063: static int
1064: show_key_from_file(const char *file, const char *host, int keytype)
1065: {
1066: Key *found;
1.204 grunk 1067: char *fp, *ra;
1.132 markus 1068: int line, ret;
1069:
1070: found = key_new(keytype);
1071: if ((ret = lookup_key_in_hostfile_by_type(file, host,
1072: keytype, found, &line))) {
1073: fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1.204 grunk 1074: ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART);
1.138 itojun 1075: logit("WARNING: %s key found for host %s\n"
1.133 markus 1076: "in %s:%d\n"
1.204 grunk 1077: "%s key fingerprint %s.\n%s\n",
1.132 markus 1078: key_type(found), host, file, line,
1.204 grunk 1079: key_type(found), fp, ra);
1080: xfree(ra);
1.132 markus 1081: xfree(fp);
1082: }
1083: key_free(found);
1084: return (ret);
1085: }
1086:
1087: /* print all known host keys for a given host, but skip keys of given type */
1088: static int
1089: show_other_keys(const char *host, Key *key)
1090: {
1091: int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1092: int i, found = 0;
1093:
1094: for (i = 0; type[i] != -1; i++) {
1095: if (type[i] == key->type)
1096: continue;
1097: if (type[i] != KEY_RSA1 &&
1098: show_key_from_file(options.user_hostfile2, host, type[i])) {
1099: found = 1;
1100: continue;
1101: }
1102: if (type[i] != KEY_RSA1 &&
1103: show_key_from_file(options.system_hostfile2, host, type[i])) {
1104: found = 1;
1105: continue;
1106: }
1107: if (show_key_from_file(options.user_hostfile, host, type[i])) {
1108: found = 1;
1109: continue;
1110: }
1111: if (show_key_from_file(options.system_hostfile, host, type[i])) {
1112: found = 1;
1113: continue;
1114: }
1115: debug2("no key of type %d for host %s", type[i], host);
1116: }
1117: return (found);
1.150 jakob 1118: }
1119:
1120: static void
1121: warn_changed_key(Key *host_key)
1122: {
1123: char *fp;
1.151 jakob 1124: const char *type = key_type(host_key);
1.150 jakob 1125:
1126: fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1127:
1128: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1129: error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1130: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1131: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1132: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1133: error("It is also possible that the %s host key has just been changed.", type);
1134: error("The fingerprint for the %s key sent by the remote host is\n%s.",
1135: type, fp);
1136: error("Please contact your system administrator.");
1137:
1138: xfree(fp);
1.171 reyk 1139: }
1140:
1141: /*
1142: * Execute a local command
1143: */
1144: int
1145: ssh_local_cmd(const char *args)
1146: {
1147: char *shell;
1148: pid_t pid;
1149: int status;
1150:
1151: if (!options.permit_local_command ||
1152: args == NULL || !*args)
1153: return (1);
1154:
1155: if ((shell = getenv("SHELL")) == NULL)
1156: shell = _PATH_BSHELL;
1157:
1158: pid = fork();
1159: if (pid == 0) {
1160: debug3("Executing %s -c \"%s\"", shell, args);
1161: execl(shell, shell, "-c", args, (char *)NULL);
1162: error("Couldn't execute %s -c \"%s\": %s",
1163: shell, args, strerror(errno));
1164: _exit(1);
1165: } else if (pid == -1)
1166: fatal("fork failed: %.100s", strerror(errno));
1167: while (waitpid(pid, &status, 0) == -1)
1168: if (errno != EINTR)
1169: fatal("Couldn't wait for child: %s", strerror(errno));
1170:
1171: if (!WIFEXITED(status))
1172: return (1);
1173:
1174: return (WEXITSTATUS(status));
1.1 deraadt 1175: }
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