[BACK]Return to sshconnect.c CVS log [TXT][DIR] Up to [local] / src / usr.bin / ssh

Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.202

1.202   ! djm         1: /* $OpenBSD: sshconnect.c,v 1.201 2007/08/23 03:23:26 djm 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;
                    211:        gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
                    212:        if (gaierr) {
                    213:                error("getaddrinfo: %s: %s", options.bind_address,
                    214:                    gai_strerror(gaierr));
                    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)
1.50      markus    346:                fatal("%s: %.100s: %s", __progname, host,
                    347:                    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;
1.100     markus    592:        char hostline[1000], *hostp, *fp;
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;
1.49      markus    600:
                    601:        /*
                    602:         * Force accepting of the host key for loopback/localhost. The
                    603:         * problem is that if the home directory is NFS-mounted to multiple
                    604:         * machines, localhost will refer to a different machine in each of
                    605:         * them, and the user will get bogus HOST_CHANGED warnings.  This
                    606:         * essentially disables host authentication for localhost; however,
                    607:         * this is probably not a real problem.
                    608:         */
1.70      markus    609:        /**  hostaddr == 0! */
1.49      markus    610:        switch (hostaddr->sa_family) {
                    611:        case AF_INET:
1.108     markus    612:                local = (ntohl(((struct sockaddr_in *)hostaddr)->
1.168     djm       613:                    sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
1.49      markus    614:                break;
                    615:        case AF_INET6:
1.108     markus    616:                local = IN6_IS_ADDR_LOOPBACK(
                    617:                    &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
1.49      markus    618:                break;
                    619:        default:
                    620:                local = 0;
                    621:                break;
                    622:        }
1.111     markus    623:        if (options.no_host_authentication_for_localhost == 1 && local &&
                    624:            options.host_key_alias == NULL) {
1.88      markus    625:                debug("Forcing accepting of host key for "
                    626:                    "loopback/localhost.");
1.108     markus    627:                return 0;
1.49      markus    628:        }
1.42      markus    629:
                    630:        /*
1.88      markus    631:         * We don't have the remote ip-address for connections
                    632:         * using a proxy command
1.42      markus    633:         */
1.84      markus    634:        if (options.proxy_command == NULL) {
                    635:                if (getnameinfo(hostaddr, hostaddr->sa_len, ntop, sizeof(ntop),
1.86      markus    636:                    NULL, 0, NI_NUMERICHOST) != 0)
1.84      markus    637:                        fatal("check_host_key: getnameinfo failed");
1.197     dtucker   638:                ip = put_host_port(ntop, port);
1.84      markus    639:        } else {
                    640:                ip = xstrdup("<no hostip for proxy command>");
1.86      markus    641:        }
1.88      markus    642:        /*
                    643:         * Turn off check_host_ip if the connection is to localhost, via proxy
                    644:         * command or if we don't have a hostname to compare with
                    645:         */
1.189     dtucker   646:        if (options.check_host_ip && (local ||
                    647:            strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
1.88      markus    648:                options.check_host_ip = 0;
1.86      markus    649:
                    650:        /*
1.189     dtucker   651:         * Allow the user to record the key under a different name or
                    652:         * differentiate a non-standard port.  This is useful for ssh
                    653:         * tunneling over forwarded connections or if you run multiple
                    654:         * sshd's on different ports on the same machine.
1.86      markus    655:         */
                    656:        if (options.host_key_alias != NULL) {
1.189     dtucker   657:                host = xstrdup(options.host_key_alias);
1.86      markus    658:                debug("using hostkeyalias: %s", host);
1.189     dtucker   659:        } else {
1.197     dtucker   660:                host = put_host_port(hostname, port);
1.84      markus    661:        }
1.38      markus    662:
1.46      markus    663:        /*
                    664:         * Store the host key from the known host file in here so that we can
                    665:         * compare it with the key for the IP address.
                    666:         */
1.58      markus    667:        file_key = key_new(host_key->type);
1.38      markus    668:
1.40      markus    669:        /*
1.170     djm       670:         * Check if the host key is present in the user's list of known
1.40      markus    671:         * hosts or in the systemwide list.
                    672:         */
1.85      markus    673:        host_file = user_hostfile;
1.108     markus    674:        host_status = check_host_in_hostfile(host_file, host, host_key,
1.118     deraadt   675:            file_key, &host_line);
1.85      markus    676:        if (host_status == HOST_NEW) {
                    677:                host_file = system_hostfile;
1.108     markus    678:                host_status = check_host_in_hostfile(host_file, host, host_key,
                    679:                    file_key, &host_line);
1.85      markus    680:        }
1.40      markus    681:        /*
                    682:         * Also perform check for the ip address, skip the check if we are
                    683:         * localhost or the hostname was an ip address to begin with
                    684:         */
1.88      markus    685:        if (options.check_host_ip) {
1.58      markus    686:                Key *ip_key = key_new(host_key->type);
1.38      markus    687:
1.85      markus    688:                ip_file = user_hostfile;
1.108     markus    689:                ip_status = check_host_in_hostfile(ip_file, ip, host_key,
                    690:                    ip_key, &ip_line);
1.85      markus    691:                if (ip_status == HOST_NEW) {
                    692:                        ip_file = system_hostfile;
1.108     markus    693:                        ip_status = check_host_in_hostfile(ip_file, ip,
                    694:                            host_key, ip_key, &ip_line);
1.85      markus    695:                }
1.38      markus    696:                if (host_status == HOST_CHANGED &&
1.58      markus    697:                    (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
1.38      markus    698:                        host_ip_differ = 1;
                    699:
1.58      markus    700:                key_free(ip_key);
1.38      markus    701:        } else
                    702:                ip_status = host_status;
                    703:
1.58      markus    704:        key_free(file_key);
1.38      markus    705:
                    706:        switch (host_status) {
                    707:        case HOST_OK:
                    708:                /* The host is known and the key matches. */
1.72      markus    709:                debug("Host '%.200s' is known and matches the %s host key.",
                    710:                    host, type);
1.85      markus    711:                debug("Found key in %s:%d", host_file, host_line);
1.88      markus    712:                if (options.check_host_ip && ip_status == HOST_NEW) {
1.108     markus    713:                        if (readonly)
1.138     itojun    714:                                logit("%s host key for IP address "
1.108     markus    715:                                    "'%.128s' not in list of known hosts.",
                    716:                                    type, ip);
                    717:                        else if (!add_host_to_hostfile(user_hostfile, ip,
1.160     djm       718:                            host_key, options.hash_known_hosts))
1.138     itojun    719:                                logit("Failed to add the %s host key for IP "
1.108     markus    720:                                    "address '%.128s' to the list of known "
                    721:                                    "hosts (%.30s).", type, ip, user_hostfile);
1.88      markus    722:                        else
1.138     itojun    723:                                logit("Warning: Permanently added the %s host "
1.108     markus    724:                                    "key for IP address '%.128s' to the list "
                    725:                                    "of known hosts.", type, ip);
1.38      markus    726:                }
                    727:                break;
                    728:        case HOST_NEW:
1.197     dtucker   729:                if (options.host_key_alias == NULL && port != 0 &&
                    730:                    port != SSH_DEFAULT_PORT) {
                    731:                        debug("checking without port identifier");
                    732:                        if (check_host_key(hostname, hostaddr, 0, host_key, 2,
                    733:                            user_hostfile, system_hostfile) == 0) {
                    734:                                debug("found matching key w/out port");
                    735:                                break;
                    736:                        }
                    737:                }
1.108     markus    738:                if (readonly)
                    739:                        goto fail;
1.38      markus    740:                /* The host is new. */
                    741:                if (options.strict_host_key_checking == 1) {
1.108     markus    742:                        /*
                    743:                         * User has requested strict host key checking.  We
                    744:                         * will not add the host key automatically.  The only
                    745:                         * alternative left is to abort.
                    746:                         */
                    747:                        error("No %s host key is known for %.200s and you "
                    748:                            "have requested strict checking.", type, host);
                    749:                        goto fail;
1.38      markus    750:                } else if (options.strict_host_key_checking == 2) {
1.145     jakob     751:                        char msg1[1024], msg2[1024];
                    752:
                    753:                        if (show_other_keys(host, host_key))
                    754:                                snprintf(msg1, sizeof(msg1),
1.168     djm       755:                                    "\nbut keys of different type are already"
                    756:                                    " known for this host.");
1.145     jakob     757:                        else
                    758:                                snprintf(msg1, sizeof(msg1), ".");
1.38      markus    759:                        /* The default */
1.100     markus    760:                        fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1.145     jakob     761:                        msg2[0] = '\0';
                    762:                        if (options.verify_host_key_dns) {
1.153     jakob     763:                                if (matching_host_key_dns)
1.145     jakob     764:                                        snprintf(msg2, sizeof(msg2),
                    765:                                            "Matching host key fingerprint"
                    766:                                            " found in DNS.\n");
                    767:                                else
                    768:                                        snprintf(msg2, sizeof(msg2),
                    769:                                            "No matching host key fingerprint"
                    770:                                            " found in DNS.\n");
                    771:                        }
1.119     markus    772:                        snprintf(msg, sizeof(msg),
1.108     markus    773:                            "The authenticity of host '%.200s (%s)' can't be "
1.132     markus    774:                            "established%s\n"
1.145     jakob     775:                            "%s key fingerprint is %s.\n%s"
1.108     markus    776:                            "Are you sure you want to continue connecting "
1.132     markus    777:                            "(yes/no)? ",
1.145     jakob     778:                            host, ip, msg1, type, fp, msg2);
1.100     markus    779:                        xfree(fp);
1.119     markus    780:                        if (!confirm(msg))
1.108     markus    781:                                goto fail;
1.38      markus    782:                }
1.161     djm       783:                /*
                    784:                 * If not in strict mode, add the key automatically to the
                    785:                 * local known_hosts file.
                    786:                 */
1.88      markus    787:                if (options.check_host_ip && ip_status == HOST_NEW) {
1.161     djm       788:                        snprintf(hostline, sizeof(hostline), "%s,%s",
                    789:                            host, ip);
1.38      markus    790:                        hostp = hostline;
1.161     djm       791:                        if (options.hash_known_hosts) {
                    792:                                /* Add hash of host and IP separately */
                    793:                                r = add_host_to_hostfile(user_hostfile, host,
                    794:                                    host_key, options.hash_known_hosts) &&
                    795:                                    add_host_to_hostfile(user_hostfile, ip,
                    796:                                    host_key, options.hash_known_hosts);
                    797:                        } else {
                    798:                                /* Add unhashed "host,ip" */
                    799:                                r = add_host_to_hostfile(user_hostfile,
                    800:                                    hostline, host_key,
                    801:                                    options.hash_known_hosts);
                    802:                        }
                    803:                } else {
                    804:                        r = add_host_to_hostfile(user_hostfile, host, host_key,
                    805:                            options.hash_known_hosts);
1.38      markus    806:                        hostp = host;
1.161     djm       807:                }
1.38      markus    808:
1.161     djm       809:                if (!r)
1.138     itojun    810:                        logit("Failed to add the host to the list of known "
1.108     markus    811:                            "hosts (%.500s).", user_hostfile);
1.38      markus    812:                else
1.138     itojun    813:                        logit("Warning: Permanently added '%.200s' (%s) to the "
1.108     markus    814:                            "list of known hosts.", hostp, type);
1.38      markus    815:                break;
                    816:        case HOST_CHANGED:
1.197     dtucker   817:                if (readonly == ROQUIET)
                    818:                        goto fail;
1.38      markus    819:                if (options.check_host_ip && host_ip_differ) {
1.158     avsm      820:                        char *key_msg;
1.38      markus    821:                        if (ip_status == HOST_NEW)
1.158     avsm      822:                                key_msg = "is unknown";
1.38      markus    823:                        else if (ip_status == HOST_OK)
1.158     avsm      824:                                key_msg = "is unchanged";
1.38      markus    825:                        else
1.158     avsm      826:                                key_msg = "has a different value";
1.38      markus    827:                        error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
                    828:                        error("@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @");
                    829:                        error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1.72      markus    830:                        error("The %s host key for %s has changed,", type, host);
1.38      markus    831:                        error("and the key for the according IP address %s", ip);
1.158     avsm      832:                        error("%s. This could either mean that", key_msg);
1.38      markus    833:                        error("DNS SPOOFING is happening or the IP address for the host");
1.85      markus    834:                        error("and its host key have changed at the same time.");
1.88      markus    835:                        if (ip_status != HOST_NEW)
1.85      markus    836:                                error("Offending key for IP in %s:%d", ip_file, ip_line);
1.38      markus    837:                }
                    838:                /* The host key has changed. */
1.150     jakob     839:                warn_changed_key(host_key);
1.38      markus    840:                error("Add correct host key in %.100s to get rid of this message.",
1.87      markus    841:                    user_hostfile);
1.85      markus    842:                error("Offending key in %s:%d", host_file, host_line);
1.38      markus    843:
1.40      markus    844:                /*
                    845:                 * If strict host key checking is in use, the user will have
                    846:                 * to edit the key manually and we can only abort.
                    847:                 */
1.108     markus    848:                if (options.strict_host_key_checking) {
                    849:                        error("%s host key for %.200s has changed and you have "
                    850:                            "requested strict checking.", type, host);
                    851:                        goto fail;
                    852:                }
1.38      markus    853:
1.40      markus    854:                /*
                    855:                 * If strict host key checking has not been requested, allow
1.144     djm       856:                 * the connection but without MITM-able authentication or
1.194     stevesk   857:                 * forwarding.
1.40      markus    858:                 */
1.38      markus    859:                if (options.password_authentication) {
1.108     markus    860:                        error("Password authentication is disabled to avoid "
                    861:                            "man-in-the-middle attacks.");
1.38      markus    862:                        options.password_authentication = 0;
1.144     djm       863:                }
                    864:                if (options.kbd_interactive_authentication) {
                    865:                        error("Keyboard-interactive authentication is disabled"
                    866:                            " to avoid man-in-the-middle attacks.");
                    867:                        options.kbd_interactive_authentication = 0;
                    868:                        options.challenge_response_authentication = 0;
                    869:                }
                    870:                if (options.challenge_response_authentication) {
                    871:                        error("Challenge/response authentication is disabled"
                    872:                            " to avoid man-in-the-middle attacks.");
                    873:                        options.challenge_response_authentication = 0;
1.38      markus    874:                }
                    875:                if (options.forward_agent) {
1.108     markus    876:                        error("Agent forwarding is disabled to avoid "
                    877:                            "man-in-the-middle attacks.");
1.38      markus    878:                        options.forward_agent = 0;
1.83      markus    879:                }
                    880:                if (options.forward_x11) {
1.108     markus    881:                        error("X11 forwarding is disabled to avoid "
                    882:                            "man-in-the-middle attacks.");
1.83      markus    883:                        options.forward_x11 = 0;
                    884:                }
1.108     markus    885:                if (options.num_local_forwards > 0 ||
                    886:                    options.num_remote_forwards > 0) {
                    887:                        error("Port forwarding is disabled to avoid "
                    888:                            "man-in-the-middle attacks.");
                    889:                        options.num_local_forwards =
1.118     deraadt   890:                            options.num_remote_forwards = 0;
1.194     stevesk   891:                }
                    892:                if (options.tun_open != SSH_TUNMODE_NO) {
                    893:                        error("Tunnel forwarding is disabled to avoid "
                    894:                            "man-in-the-middle attacks.");
                    895:                        options.tun_open = SSH_TUNMODE_NO;
1.38      markus    896:                }
1.40      markus    897:                /*
                    898:                 * XXX Should permit the user to change to use the new id.
                    899:                 * This could be done by converting the host key to an
                    900:                 * identifying sentence, tell that the host identifies itself
                    901:                 * by that sentence, and ask the user if he/she whishes to
                    902:                 * accept the authentication.
                    903:                 */
1.38      markus    904:                break;
1.132     markus    905:        case HOST_FOUND:
                    906:                fatal("internal error");
                    907:                break;
1.88      markus    908:        }
                    909:
                    910:        if (options.check_host_ip && host_status != HOST_CHANGED &&
                    911:            ip_status == HOST_CHANGED) {
1.119     markus    912:                snprintf(msg, sizeof(msg),
                    913:                    "Warning: the %s host key for '%.200s' "
                    914:                    "differs from the key for the IP address '%.128s'"
                    915:                    "\nOffending key for IP in %s:%d",
                    916:                    type, host, ip, ip_file, ip_line);
                    917:                if (host_status == HOST_OK) {
                    918:                        len = strlen(msg);
                    919:                        snprintf(msg + len, sizeof(msg) - len,
                    920:                            "\nMatching host key in %s:%d",
1.125     deraadt   921:                            host_file, host_line);
1.119     markus    922:                }
1.88      markus    923:                if (options.strict_host_key_checking == 1) {
1.143     djm       924:                        logit("%s", msg);
1.108     markus    925:                        error("Exiting, you have requested strict checking.");
                    926:                        goto fail;
1.88      markus    927:                } else if (options.strict_host_key_checking == 2) {
1.119     markus    928:                        strlcat(msg, "\nAre you sure you want "
                    929:                            "to continue connecting (yes/no)? ", sizeof(msg));
                    930:                        if (!confirm(msg))
1.108     markus    931:                                goto fail;
1.119     markus    932:                } else {
1.143     djm       933:                        logit("%s", msg);
1.88      markus    934:                }
1.38      markus    935:        }
1.82      provos    936:
                    937:        xfree(ip);
1.189     dtucker   938:        xfree(host);
1.108     markus    939:        return 0;
                    940:
                    941: fail:
                    942:        xfree(ip);
1.189     dtucker   943:        xfree(host);
1.108     markus    944:        return -1;
                    945: }
                    946:
1.140     jakob     947: /* returns 0 if key verifies or -1 if key does NOT verify */
1.108     markus    948: int
                    949: verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
                    950: {
                    951:        struct stat st;
1.153     jakob     952:        int flags = 0;
1.140     jakob     953:
1.153     jakob     954:        if (options.verify_host_key_dns &&
                    955:            verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
                    956:
                    957:                if (flags & DNS_VERIFY_FOUND) {
                    958:
                    959:                        if (options.verify_host_key_dns == 1 &&
                    960:                            flags & DNS_VERIFY_MATCH &&
                    961:                            flags & DNS_VERIFY_SECURE)
                    962:                                return 0;
                    963:
                    964:                        if (flags & DNS_VERIFY_MATCH) {
                    965:                                matching_host_key_dns = 1;
                    966:                        } else {
                    967:                                warn_changed_key(host_key);
                    968:                                error("Update the SSHFP RR in DNS with the new "
                    969:                                    "host key to get rid of this message.");
                    970:                        }
1.140     jakob     971:                }
                    972:        }
1.108     markus    973:
                    974:        /* return ok if the key can be found in an old keyfile */
                    975:        if (stat(options.system_hostfile2, &st) == 0 ||
                    976:            stat(options.user_hostfile2, &st) == 0) {
1.197     dtucker   977:                if (check_host_key(host, hostaddr, options.port, host_key,
                    978:                    RDONLY, options.user_hostfile2,
                    979:                    options.system_hostfile2) == 0)
1.108     markus    980:                        return 0;
                    981:        }
1.197     dtucker   982:        return check_host_key(host, hostaddr, options.port, host_key,
                    983:            RDRW, options.user_hostfile, options.system_hostfile);
1.51      markus    984: }
1.70      markus    985:
1.51      markus    986: /*
                    987:  * Starts a dialog with the server, and authenticates the current user on the
                    988:  * server.  This does not need any extra privileges.  The basic connection
                    989:  * to the server must already have been established before this is called.
                    990:  * If login fails, this function prints an error and never returns.
                    991:  * This function does not require super-user privileges.
                    992:  */
                    993: void
1.120     markus    994: ssh_login(Sensitive *sensitive, const char *orighost,
1.202   ! djm       995:     struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms)
1.51      markus    996: {
                    997:        char *host, *cp;
1.70      markus    998:        char *server_user, *local_user;
                    999:
                   1000:        local_user = xstrdup(pw->pw_name);
                   1001:        server_user = options.user ? options.user : local_user;
1.51      markus   1002:
                   1003:        /* Convert the user-supplied hostname into all lowercase. */
                   1004:        host = xstrdup(orighost);
                   1005:        for (cp = host; *cp; cp++)
                   1006:                if (isupper(*cp))
1.178     deraadt  1007:                        *cp = (char)tolower(*cp);
1.51      markus   1008:
                   1009:        /* Exchange protocol version identification strings with the server. */
1.202   ! djm      1010:        ssh_exchange_identification(timeout_ms);
1.51      markus   1011:
                   1012:        /* Put the connection into non-blocking mode. */
                   1013:        packet_set_nonblocking();
                   1014:
                   1015:        /* key exchange */
                   1016:        /* authenticate user */
1.59      markus   1017:        if (compat20) {
                   1018:                ssh_kex2(host, hostaddr);
1.120     markus   1019:                ssh_userauth2(local_user, server_user, host, sensitive);
1.59      markus   1020:        } else {
                   1021:                ssh_kex(host, hostaddr);
1.120     markus   1022:                ssh_userauth1(local_user, server_user, host, sensitive);
1.59      markus   1023:        }
1.182     markus   1024:        xfree(local_user);
1.97      markus   1025: }
                   1026:
                   1027: void
                   1028: ssh_put_password(char *password)
                   1029: {
                   1030:        int size;
                   1031:        char *padded;
                   1032:
1.99      deraadt  1033:        if (datafellows & SSH_BUG_PASSWORDPAD) {
1.107     markus   1034:                packet_put_cstring(password);
1.99      deraadt  1035:                return;
                   1036:        }
1.97      markus   1037:        size = roundup(strlen(password) + 1, 32);
1.179     djm      1038:        padded = xcalloc(1, size);
1.97      markus   1039:        strlcpy(padded, password, size);
                   1040:        packet_put_string(padded, size);
                   1041:        memset(padded, 0, size);
                   1042:        xfree(padded);
1.132     markus   1043: }
                   1044:
                   1045: static int
                   1046: show_key_from_file(const char *file, const char *host, int keytype)
                   1047: {
                   1048:        Key *found;
                   1049:        char *fp;
                   1050:        int line, ret;
                   1051:
                   1052:        found = key_new(keytype);
                   1053:        if ((ret = lookup_key_in_hostfile_by_type(file, host,
                   1054:            keytype, found, &line))) {
                   1055:                fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1.138     itojun   1056:                logit("WARNING: %s key found for host %s\n"
1.133     markus   1057:                    "in %s:%d\n"
1.132     markus   1058:                    "%s key fingerprint %s.",
                   1059:                    key_type(found), host, file, line,
                   1060:                    key_type(found), fp);
                   1061:                xfree(fp);
                   1062:        }
                   1063:        key_free(found);
                   1064:        return (ret);
                   1065: }
                   1066:
                   1067: /* print all known host keys for a given host, but skip keys of given type */
                   1068: static int
                   1069: show_other_keys(const char *host, Key *key)
                   1070: {
                   1071:        int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
                   1072:        int i, found = 0;
                   1073:
                   1074:        for (i = 0; type[i] != -1; i++) {
                   1075:                if (type[i] == key->type)
                   1076:                        continue;
                   1077:                if (type[i] != KEY_RSA1 &&
                   1078:                    show_key_from_file(options.user_hostfile2, host, type[i])) {
                   1079:                        found = 1;
                   1080:                        continue;
                   1081:                }
                   1082:                if (type[i] != KEY_RSA1 &&
                   1083:                    show_key_from_file(options.system_hostfile2, host, type[i])) {
                   1084:                        found = 1;
                   1085:                        continue;
                   1086:                }
                   1087:                if (show_key_from_file(options.user_hostfile, host, type[i])) {
                   1088:                        found = 1;
                   1089:                        continue;
                   1090:                }
                   1091:                if (show_key_from_file(options.system_hostfile, host, type[i])) {
                   1092:                        found = 1;
                   1093:                        continue;
                   1094:                }
                   1095:                debug2("no key of type %d for host %s", type[i], host);
                   1096:        }
                   1097:        return (found);
1.150     jakob    1098: }
                   1099:
                   1100: static void
                   1101: warn_changed_key(Key *host_key)
                   1102: {
                   1103:        char *fp;
1.151     jakob    1104:        const char *type = key_type(host_key);
1.150     jakob    1105:
                   1106:        fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
                   1107:
                   1108:        error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
                   1109:        error("@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @");
                   1110:        error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
                   1111:        error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
                   1112:        error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
                   1113:        error("It is also possible that the %s host key has just been changed.", type);
                   1114:        error("The fingerprint for the %s key sent by the remote host is\n%s.",
                   1115:            type, fp);
                   1116:        error("Please contact your system administrator.");
                   1117:
                   1118:        xfree(fp);
1.171     reyk     1119: }
                   1120:
                   1121: /*
                   1122:  * Execute a local command
                   1123:  */
                   1124: int
                   1125: ssh_local_cmd(const char *args)
                   1126: {
                   1127:        char *shell;
                   1128:        pid_t pid;
                   1129:        int status;
                   1130:
                   1131:        if (!options.permit_local_command ||
                   1132:            args == NULL || !*args)
                   1133:                return (1);
                   1134:
                   1135:        if ((shell = getenv("SHELL")) == NULL)
                   1136:                shell = _PATH_BSHELL;
                   1137:
                   1138:        pid = fork();
                   1139:        if (pid == 0) {
                   1140:                debug3("Executing %s -c \"%s\"", shell, args);
                   1141:                execl(shell, shell, "-c", args, (char *)NULL);
                   1142:                error("Couldn't execute %s -c \"%s\": %s",
                   1143:                    shell, args, strerror(errno));
                   1144:                _exit(1);
                   1145:        } else if (pid == -1)
                   1146:                fatal("fork failed: %.100s", strerror(errno));
                   1147:        while (waitpid(pid, &status, 0) == -1)
                   1148:                if (errno != EINTR)
                   1149:                        fatal("Couldn't wait for child: %s", strerror(errno));
                   1150:
                   1151:        if (!WIFEXITED(status))
                   1152:                return (1);
                   1153:
                   1154:        return (WEXITSTATUS(status));
1.1       deraadt  1155: }