X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/8d9bb5dd3a72a29c0a553f634587b068b5dad80a..7ca4010c51e5d143ce6a4684a8f4b7c4e74905a3:/sshd.c diff --git a/sshd.c b/sshd.c index bc458488..a206db24 100644 --- a/sshd.c +++ b/sshd.c @@ -1,3 +1,4 @@ +/* $OpenBSD: sshd.c,v 1.330 2006/03/25 13:17:02 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -42,7 +43,18 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.268 2003/06/04 10:23:48 djm Exp $"); + +#include +#ifdef HAVE_SYS_STAT_H +# include +#endif +#include +#include + +#ifdef HAVE_PATHS_H +#include +#endif +#include #include #include @@ -60,12 +72,12 @@ RCSID("$OpenBSD: sshd.c,v 1.268 2003/06/04 10:23:48 djm Exp $"); #include "rsa.h" #include "sshpty.h" #include "packet.h" -#include "mpaux.h" #include "log.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" #include "buffer.h" +#include "bufaux.h" #include "cipher.h" #include "kex.h" #include "key.h" @@ -77,6 +89,7 @@ RCSID("$OpenBSD: sshd.c,v 1.268 2003/06/04 10:23:48 djm Exp $"); #include "canohost.h" #include "auth.h" #include "misc.h" +#include "msg.h" #include "dispatch.h" #include "channels.h" #include "session.h" @@ -96,11 +109,13 @@ int deny_severity = LOG_WARNING; #define O_NOCTTY 0 #endif -#ifdef HAVE___PROGNAME +/* Re-exec fds */ +#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) +#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) +#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) +#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) + extern char *__progname; -#else -char *__progname; -#endif /* Server configuration options. */ ServerOptions options; @@ -108,12 +123,6 @@ ServerOptions options; /* Name of the server configuration file. */ char *config_file_name = _PATH_SERVER_CONFIG_FILE; -/* - * Flag indicating whether IPv4 or IPv6. This can be set on the command line. - * Default value is AF_UNSPEC means both IPv4 and IPv6. - */ -int IPv4or6 = AF_UNSPEC; - /* * Debug mode flag. This can be set on the command line. If debug * mode is enabled, extra debugging output will be sent to the system @@ -138,6 +147,12 @@ int log_stderr = 0; char **saved_argv; int saved_argc; +/* re-exec */ +int rexeced_flag = 0; +int rexec_flag = 1; +int rexec_argc = 0; +char **rexec_argv; + /* * The sockets that the server is listening; this is used in the SIGHUP * signal handler. @@ -188,7 +203,7 @@ u_char session_id[16]; /* same for ssh2 */ u_char *session_id2 = NULL; -int session_id2_len = 0; +u_int session_id2_len = 0; /* record remote hostname or ip */ u_int utmp_len = MAXHOSTNAMELEN; @@ -199,7 +214,13 @@ int startup_pipe; /* in child */ /* variables used for privilege separation */ int use_privsep; -struct monitor *pmonitor; +struct monitor *pmonitor = NULL; + +/* global authentication context */ +Authctxt *the_authctxt = NULL; + +/* message to be displayed after login */ +Buffer loginmsg; /* Prototypes for various functions defined later in this file. */ void destroy_sensitive_data(void); @@ -237,6 +258,8 @@ close_startup_pipes(void) * the effect is to reread the configuration file (and to regenerate * the server key). */ + +/*ARGSUSED*/ static void sighup_handler(int sig) { @@ -266,6 +289,7 @@ sighup_restart(void) /* * Generic signal handler for terminating signals in the master daemon. */ +/*ARGSUSED*/ static void sigterm_handler(int sig) { @@ -276,6 +300,7 @@ sigterm_handler(int sig) * SIGCHLD handler. This is called whenever a child dies. This will then * reap any zombies left by exited children. */ +/*ARGSUSED*/ static void main_sigchld_handler(int sig) { @@ -294,11 +319,15 @@ main_sigchld_handler(int sig) /* * Signal handler for the alarm after the login grace period has expired. */ +/*ARGSUSED*/ static void grace_alarm_handler(int sig) { /* XXX no idea how fix this signal handler */ + if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) + kill(pmonitor->m_pid, SIGALRM); + /* Log error and exit. */ fatal("Timeout before authentication for %s", get_remote_ipaddr()); } @@ -333,6 +362,7 @@ generate_ephemeral_server_key(void) arc4random_stir(); } +/*ARGSUSED*/ static void key_regeneration_alarm(int sig) { @@ -346,7 +376,8 @@ key_regeneration_alarm(int sig) static void sshd_exchange_identification(int sock_in, int sock_out) { - int i, mismatch; + u_int i; + int mismatch; int remote_major, remote_minor; int major, minor; char *s; @@ -367,39 +398,37 @@ sshd_exchange_identification(int sock_in, int sock_out) snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); server_version_string = xstrdup(buf); - if (client_version_string == NULL) { - /* Send our protocol version identification. */ - if (atomicio(write, sock_out, server_version_string, - strlen(server_version_string)) - != strlen(server_version_string)) { - logit("Could not write ident string to %s", get_remote_ipaddr()); - fatal_cleanup(); - } + /* Send our protocol version identification. */ + if (atomicio(vwrite, sock_out, server_version_string, + strlen(server_version_string)) + != strlen(server_version_string)) { + logit("Could not write ident string to %s", get_remote_ipaddr()); + cleanup_exit(255); + } - /* Read other sides version identification. */ - memset(buf, 0, sizeof(buf)); - for (i = 0; i < sizeof(buf) - 1; i++) { - if (atomicio(read, sock_in, &buf[i], 1) != 1) { - logit("Did not receive identification string from %s", - get_remote_ipaddr()); - fatal_cleanup(); - } - if (buf[i] == '\r') { - buf[i] = 0; - /* Kludge for F-Secure Macintosh < 1.0.2 */ - if (i == 12 && - strncmp(buf, "SSH-1.5-W1.0", 12) == 0) - break; - continue; - } - if (buf[i] == '\n') { - buf[i] = 0; + /* Read other sides version identification. */ + memset(buf, 0, sizeof(buf)); + for (i = 0; i < sizeof(buf) - 1; i++) { + if (atomicio(read, sock_in, &buf[i], 1) != 1) { + logit("Did not receive identification string from %s", + get_remote_ipaddr()); + cleanup_exit(255); + } + if (buf[i] == '\r') { + buf[i] = 0; + /* Kludge for F-Secure Macintosh < 1.0.2 */ + if (i == 12 && + strncmp(buf, "SSH-1.5-W1.0", 12) == 0) break; - } + continue; + } + if (buf[i] == '\n') { + buf[i] = 0; + break; } - buf[sizeof(buf) - 1] = 0; - client_version_string = xstrdup(buf); } + buf[sizeof(buf) - 1] = 0; + client_version_string = xstrdup(buf); /* * Check that the versions match. In future this might accept @@ -408,12 +437,12 @@ sshd_exchange_identification(int sock_in, int sock_out) if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, remote_version) != 3) { s = "Protocol mismatch.\n"; - (void) atomicio(write, sock_out, s, strlen(s)); + (void) atomicio(vwrite, sock_out, s, strlen(s)); close(sock_in); close(sock_out); logit("Bad protocol version identification '%.100s' from %s", client_version_string, get_remote_ipaddr()); - fatal_cleanup(); + cleanup_exit(255); } debug("Client protocol version %d.%d; client software version %.100s", remote_major, remote_minor, remote_version); @@ -423,13 +452,13 @@ sshd_exchange_identification(int sock_in, int sock_out) if (datafellows & SSH_BUG_PROBE) { logit("probed from %s with %s. Don't panic.", get_remote_ipaddr(), client_version_string); - fatal_cleanup(); + cleanup_exit(255); } if (datafellows & SSH_BUG_SCANNER) { logit("scanned from %s with %s. Don't panic.", get_remote_ipaddr(), client_version_string); - fatal_cleanup(); + cleanup_exit(255); } mismatch = 0; @@ -469,13 +498,13 @@ sshd_exchange_identification(int sock_in, int sock_out) if (mismatch) { s = "Protocol major versions differ.\n"; - (void) atomicio(write, sock_out, s, strlen(s)); + (void) atomicio(vwrite, sock_out, s, strlen(s)); close(sock_in); close(sock_out); logit("Protocol major versions differ for %s: %.200s vs. %.200s", get_remote_ipaddr(), server_version_string, client_version_string); - fatal_cleanup(); + cleanup_exit(255); } } @@ -560,7 +589,7 @@ privsep_preauth_child(void) debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, (u_int)pw->pw_gid); #if 0 - /* XXX not ready, to heavy after chroot */ + /* XXX not ready, too heavy after chroot */ do_setusercontext(pw); #else gidset[0] = pw->pw_gid; @@ -570,10 +599,9 @@ privsep_preauth_child(void) #endif } -static Authctxt * -privsep_preauth(void) +static int +privsep_preauth(Authctxt *authctxt) { - Authctxt *authctxt = NULL; int status; pid_t pid; @@ -586,12 +614,11 @@ privsep_preauth(void) if (pid == -1) { fatal("fork of unprivileged child failed"); } else if (pid != 0) { - fatal_remove_cleanup((void (*) (void *)) packet_close, NULL); - debug2("Network child is on pid %ld", (long)pid); close(pmonitor->m_recvfd); - authctxt = monitor_child_preauth(pmonitor); + pmonitor->m_pid = pid; + monitor_child_preauth(authctxt, pmonitor); close(pmonitor->m_sendfd); /* Sync memory */ @@ -601,11 +628,7 @@ privsep_preauth(void) while (waitpid(pid, &status, 0) < 0) if (errno != EINTR) break; - - /* Reinstall, since the child has finished */ - fatal_add_cleanup((void (*) (void *)) packet_close, NULL); - - return (authctxt); + return (1); } else { /* child */ @@ -616,33 +639,20 @@ privsep_preauth(void) privsep_preauth_child(); setproctitle("%s", "[net]"); } - return (NULL); + return (0); } static void privsep_postauth(Authctxt *authctxt) { - extern Authctxt *x_authctxt; - - /* XXX - Remote port forwarding */ - x_authctxt = authctxt; - #ifdef DISABLE_FD_PASSING if (1) { #else if (authctxt->pw->pw_uid == 0 || options.use_login) { #endif /* File descriptor passing is broken or root login */ - monitor_apply_keystate(pmonitor); use_privsep = 0; - return; - } - - /* Authentication complete */ - alarm(0); - if (startup_pipe != -1) { - close(startup_pipe); - startup_pipe = -1; + goto skip; } /* New socket pair */ @@ -652,10 +662,9 @@ privsep_postauth(Authctxt *authctxt) if (pmonitor->m_pid == -1) fatal("fork of unprivileged child failed"); else if (pmonitor->m_pid != 0) { - fatal_remove_cleanup((void (*) (void *)) packet_close, NULL); - debug2("User child is on pid %ld", (long)pmonitor->m_pid); close(pmonitor->m_recvfd); + buffer_clear(&loginmsg); monitor_child_postauth(pmonitor); /* NEVERREACHED */ @@ -670,15 +679,23 @@ privsep_postauth(Authctxt *authctxt) /* Drop privileges */ do_setusercontext(authctxt->pw); + skip: /* It is safe now to apply the key state */ monitor_apply_keystate(pmonitor); + + /* + * Tell the packet layer that authentication was successful, since + * this information is not part of the key state. + */ + packet_set_authenticated(); } static char * list_hostkey_types(void) { Buffer b; - char *p; + const char *p; + char *ret; int i; buffer_init(&b); @@ -697,10 +714,10 @@ list_hostkey_types(void) } } buffer_append(&b, "\0", 1); - p = xstrdup(buffer_ptr(&b)); + ret = xstrdup(buffer_ptr(&b)); buffer_free(&b); - debug("list_hostkey_types: %s", p); - return p; + debug("list_hostkey_types: %s", ret); + return ret; } Key * @@ -745,7 +762,7 @@ get_hostkey_index(Key *key) static int drop_connection(int startups) { - double p, r; + int p, r; if (startups < options.max_startups_begin) return 0; @@ -756,40 +773,117 @@ drop_connection(int startups) p = 100 - options.max_startups_rate; p *= startups - options.max_startups_begin; - p /= (double) (options.max_startups - options.max_startups_begin); + p /= options.max_startups - options.max_startups_begin; p += options.max_startups_rate; - p /= 100.0; - r = arc4random() / (double) UINT_MAX; + r = arc4random() % 100; - debug("drop_connection: p %g, r %g", p, r); + debug("drop_connection: p %d, r %d", p, r); return (r < p) ? 1 : 0; } static void usage(void) { - fprintf(stderr, "sshd version %s\n", SSH_VERSION); - fprintf(stderr, "Usage: %s [options]\n", __progname); - fprintf(stderr, "Options:\n"); - fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE); - fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n"); - fprintf(stderr, " -i Started from inetd\n"); - fprintf(stderr, " -D Do not fork into daemon mode\n"); - fprintf(stderr, " -t Only test configuration file and keys\n"); - fprintf(stderr, " -q Quiet (no logging)\n"); - fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); - fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n"); - fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n"); - fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); - fprintf(stderr, " -h file File from which to read host key (default: %s)\n", - _PATH_HOST_KEY_FILE); - fprintf(stderr, " -u len Maximum hostname length for utmp recording\n"); - fprintf(stderr, " -4 Use IPv4 only\n"); - fprintf(stderr, " -6 Use IPv6 only\n"); - fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n"); + fprintf(stderr, "%s, %s\n", + SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); + fprintf(stderr, +"usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" +" [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" + ); exit(1); } +static void +send_rexec_state(int fd, Buffer *conf) +{ + Buffer m; + + debug3("%s: entering fd = %d config len %d", __func__, fd, + buffer_len(conf)); + + /* + * Protocol from reexec master to child: + * string configuration + * u_int ephemeral_key_follows + * bignum e (only if ephemeral_key_follows == 1) + * bignum n " + * bignum d " + * bignum iqmp " + * bignum p " + * bignum q " + * string rngseed (only if OpenSSL is not self-seeded) + */ + buffer_init(&m); + buffer_put_cstring(&m, buffer_ptr(conf)); + + if (sensitive_data.server_key != NULL && + sensitive_data.server_key->type == KEY_RSA1) { + buffer_put_int(&m, 1); + buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); + buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); + buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); + buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); + buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); + buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); + } else + buffer_put_int(&m, 0); + +#ifndef OPENSSL_PRNG_ONLY + rexec_send_rng_seed(&m); +#endif + + if (ssh_msg_send(fd, 0, &m) == -1) + fatal("%s: ssh_msg_send failed", __func__); + + buffer_free(&m); + + debug3("%s: done", __func__); +} + +static void +recv_rexec_state(int fd, Buffer *conf) +{ + Buffer m; + char *cp; + u_int len; + + debug3("%s: entering fd = %d", __func__, fd); + + buffer_init(&m); + + if (ssh_msg_recv(fd, &m) == -1) + fatal("%s: ssh_msg_recv failed", __func__); + if (buffer_get_char(&m) != 0) + fatal("%s: rexec version mismatch", __func__); + + cp = buffer_get_string(&m, &len); + if (conf != NULL) + buffer_append(conf, cp, len + 1); + xfree(cp); + + if (buffer_get_int(&m)) { + if (sensitive_data.server_key != NULL) + key_free(sensitive_data.server_key); + sensitive_data.server_key = key_new_private(KEY_RSA1); + buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); + buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); + buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); + buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); + buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); + buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); + rsa_generate_additional_parameters( + sensitive_data.server_key->rsa); + } + +#ifndef OPENSSL_PRNG_ONLY + rexec_recv_rng_seed(&m); +#endif + + buffer_free(&m); + + debug3("%s: done", __func__); +} + /* * Main program for the daemon. */ @@ -798,7 +892,8 @@ main(int ac, char **av) { extern char *optarg; extern int optind; - int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1; + int opt, j, i, on = 1; + int sock_in = -1, sock_out = -1, newsock = -1; pid_t pid; socklen_t fromlen; fd_set *fdset; @@ -808,21 +903,24 @@ main(int ac, char **av) FILE *f; struct addrinfo *ai; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + char *line; int listen_sock, maxfd; - int startup_p[2]; + int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; int startups = 0; - Authctxt *authctxt; Key *key; + Authctxt *authctxt; int ret, key_used = 0; + Buffer cfg; #ifdef HAVE_SECUREWARE (void)set_auth_parameters(ac, av); #endif - __progname = get_progname(av[0]); + __progname = ssh_get_progname(av[0]); init_rng(); /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ saved_argc = ac; + rexec_argc = ac; saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); for (i = 0; i < ac; i++) saved_argv[i] = xstrdup(av[i]); @@ -834,31 +932,33 @@ main(int ac, char **av) av = saved_argv; #endif + if (geteuid() == 0 && setgroups(0, NULL) == -1) + debug("setgroups(): %.200s", strerror(errno)); + + /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ + sanitise_stdfd(); + /* Initialize configuration options to their default values. */ initialize_server_options(&options); /* Parse command-line arguments. */ - while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) { + while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { switch (opt) { case '4': - IPv4or6 = AF_INET; + options.address_family = AF_INET; break; case '6': - IPv4or6 = AF_INET6; + options.address_family = AF_INET6; break; case 'f': config_file_name = optarg; break; case 'd': - if (0 == debug_flag) { + if (debug_flag == 0) { debug_flag = 1; options.log_level = SYSLOG_LEVEL_DEBUG1; - } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) { + } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) options.log_level++; - } else { - fprintf(stderr, "Too high debugging level.\n"); - exit(1); - } break; case 'D': no_daemon_flag = 1; @@ -869,6 +969,13 @@ main(int ac, char **av) case 'i': inetd_flag = 1; break; + case 'r': + rexec_flag = 0; + break; + case 'R': + rexeced_flag = 1; + inetd_flag = 1; + break; case 'Q': /* ignored */ break; @@ -876,7 +983,8 @@ main(int ac, char **av) options.log_level = SYSLOG_LEVEL_QUIET; break; case 'b': - options.server_key_bits = atoi(optarg); + options.server_key_bits = (int)strtonum(optarg, 256, + 32768, NULL); break; case 'p': options.ports_from_cmdline = 1; @@ -909,25 +1017,22 @@ main(int ac, char **av) } options.host_key_files[options.num_host_key_files++] = optarg; break; - case 'V': - client_version_string = optarg; - /* only makes sense with inetd_flag, i.e. no listen() */ - inetd_flag = 1; - break; case 't': test_flag = 1; break; case 'u': - utmp_len = atoi(optarg); + utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); if (utmp_len > MAXHOSTNAMELEN) { fprintf(stderr, "Invalid utmp length.\n"); exit(1); } break; case 'o': - if (process_server_config_line(&options, optarg, + line = xstrdup(optarg); + if (process_server_config_line(&options, line, "command-line", 0) != 0) exit(1); + xfree(line); break; case '?': default: @@ -935,8 +1040,16 @@ main(int ac, char **av) break; } } + if (rexeced_flag || inetd_flag) + rexec_flag = 0; + if (rexec_flag && (av[0] == NULL || *av[0] != '/')) + fatal("sshd re-exec requires execution with an absolute path"); + if (rexeced_flag) + closefrom(REEXEC_MIN_FREE_FD); + else + closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); + SSLeay_add_all_algorithms(); - channel_set_af(IPv4or6); /* * Force logging to stderr until we have loaded the private host @@ -949,38 +1062,59 @@ main(int ac, char **av) SYSLOG_FACILITY_AUTH : options.log_facility, log_stderr || !inetd_flag); + /* + * Unset KRB5CCNAME, otherwise the user's session may inherit it from + * root's environment + */ + if (getenv("KRB5CCNAME") != NULL) + unsetenv("KRB5CCNAME"); + #ifdef _UNICOS - /* Cray can define user privs drop all prives now! + /* Cray can define user privs drop all privs now! * Not needed on PRIV_SU systems! */ drop_cray_privs(); #endif - seed_rng(); + sensitive_data.server_key = NULL; + sensitive_data.ssh1_host_key = NULL; + sensitive_data.have_ssh1_key = 0; + sensitive_data.have_ssh2_key = 0; + + /* Fetch our configuration */ + buffer_init(&cfg); + if (rexeced_flag) + recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); + else + load_server_config(config_file_name, &cfg); - /* Read server configuration options from the configuration file. */ - read_server_config(&options, config_file_name); + parse_server_config(&options, + rexeced_flag ? "rexec" : config_file_name, &cfg); + + if (!rexec_flag) + buffer_free(&cfg); + + seed_rng(); /* Fill in default values for those options not explicitly set. */ fill_default_server_options(&options); + /* set default channel AF */ + channel_set_af(options.address_family); + /* Check that there are no remaining arguments. */ if (optind < ac) { fprintf(stderr, "Extra argument %s.\n", av[optind]); exit(1); } - debug("sshd version %.100s", SSH_VERSION); + debug("sshd version %.100s", SSH_RELEASE); /* load private host keys */ - sensitive_data.host_keys = xmalloc(options.num_host_key_files * + sensitive_data.host_keys = xcalloc(options.num_host_key_files, sizeof(Key *)); for (i = 0; i < options.num_host_key_files; i++) sensitive_data.host_keys[i] = NULL; - sensitive_data.server_key = NULL; - sensitive_data.ssh1_host_key = NULL; - sensitive_data.have_ssh1_key = 0; - sensitive_data.have_ssh2_key = 0; for (i = 0; i < options.num_host_key_files; i++) { key = key_load_private(options.host_key_files[i], "", NULL); @@ -1043,10 +1177,9 @@ main(int ac, char **av) } if (use_privsep) { - struct passwd *pw; struct stat st; - if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) + if (getpwnam(SSH_PRIVSEP_USER) == NULL) fatal("Privilege separation user %s does not exist", SSH_PRIVSEP_USER); if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || @@ -1072,15 +1205,25 @@ main(int ac, char **av) /* * Clear out any supplemental groups we may have inherited. This * prevents inadvertent creation of files with bad modes (in the - * portable version at least, it's certainly possible for PAM - * to create a file, and we can't control the code in every + * portable version at least, it's certainly possible for PAM + * to create a file, and we can't control the code in every * module which might be used). */ if (setgroups(0, NULL) < 0) debug("setgroups() failed: %.200s", strerror(errno)); + if (rexec_flag) { + rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); + for (i = 0; i < rexec_argc; i++) { + debug("rexec_argv[%d]='%s'", i, saved_argv[i]); + rexec_argv[i] = saved_argv[i]; + } + rexec_argv[rexec_argc] = "-R"; + rexec_argv[rexec_argc + 1] = NULL; + } + /* Initialize the log (it is reinitialized below in case we forked). */ - if (debug_flag && !inetd_flag) + if (debug_flag && (!inetd_flag || rexeced_flag)) log_stderr = 1; log_init(__progname, options.log_level, options.log_facility, log_stderr); @@ -1120,19 +1263,34 @@ main(int ac, char **av) /* Start listening for a socket, unless started from inetd. */ if (inetd_flag) { - int s1; - s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */ - dup(s1); - sock_in = dup(0); - sock_out = dup(1); + int fd; + startup_pipe = -1; + if (rexeced_flag) { + close(REEXEC_CONFIG_PASS_FD); + sock_in = sock_out = dup(STDIN_FILENO); + if (!debug_flag) { + startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); + close(REEXEC_STARTUP_PIPE_FD); + } + } else { + sock_in = dup(STDIN_FILENO); + sock_out = dup(STDOUT_FILENO); + } /* * We intentionally do not close the descriptors 0, 1, and 2 - * as our code for setting the descriptors won\'t work if + * as our code for setting the descriptors won't work if * ttyfd happens to be one of those. */ + if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { + dup2(fd, STDIN_FILENO); + dup2(fd, STDOUT_FILENO); + if (fd > STDOUT_FILENO) + close(fd); + } debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); - if (options.protocol & SSH_PROTO_1) + if ((options.protocol & SSH_PROTO_1) && + sensitive_data.server_key == NULL) generate_ephemeral_server_key(); } else { for (ai = options.listen_addrs; ai; ai = ai->ai_next) { @@ -1141,10 +1299,12 @@ main(int ac, char **av) if (num_listen_socks >= MAX_LISTEN_SOCKS) fatal("Too many listen sockets. " "Enlarge MAX_LISTEN_SOCKS"); - if (getnameinfo(ai->ai_addr, ai->ai_addrlen, + if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), - NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("getnameinfo failed"); + NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { + error("getnameinfo failed: %.100s", + (ret != EAI_SYSTEM) ? gai_strerror(ret) : + strerror(errno)); continue; } /* Create socket for listening. */ @@ -1155,8 +1315,7 @@ main(int ac, char **av) verbose("socket: %.100s", strerror(errno)); continue; } - if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) { - error("listen_sock O_NONBLOCK: %s", strerror(errno)); + if (set_nonblock(listen_sock) == -1) { close(listen_sock); continue; } @@ -1182,10 +1341,10 @@ main(int ac, char **av) num_listen_socks++; /* Start listening on the port. */ + if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) + fatal("listen on [%s]:%s: %.100s", + ntop, strport, strerror(errno)); logit("Server listening on %s port %s.", ntop, strport); - if (listen(listen_sock, 5) < 0) - fatal("listen: %.100s", strerror(errno)); - } freeaddrinfo(options.listen_addrs); @@ -1217,7 +1376,10 @@ main(int ac, char **av) * overwrite any old pid in the file. */ f = fopen(options.pid_file, "wb"); - if (f) { + if (f == NULL) { + error("Couldn't create pid file \"%s\": %s", + options.pid_file, strerror(errno)); + } else { fprintf(f, "%ld\n", (long) getpid()); fclose(f); } @@ -1230,7 +1392,7 @@ main(int ac, char **av) if (listen_socks[i] > maxfd) maxfd = listen_socks[i]; /* pipes connected to unauthenticated childs */ - startup_pipes = xmalloc(options.max_startups * sizeof(int)); + startup_pipes = xcalloc(options.max_startups, sizeof(int)); for (i = 0; i < options.max_startups; i++) startup_pipes[i] = -1; @@ -1243,9 +1405,8 @@ main(int ac, char **av) sighup_restart(); if (fdset != NULL) xfree(fdset); - fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); - fdset = (fd_set *)xmalloc(fdsetsz); - memset(fdset, 0, fdsetsz); + fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), + sizeof(fd_mask)); for (i = 0; i < num_listen_socks; i++) FD_SET(listen_socks[i], fdset); @@ -1289,15 +1450,14 @@ main(int ac, char **av) if (!FD_ISSET(listen_socks[i], fdset)) continue; fromlen = sizeof(from); - newsock = accept(listen_socks[i], (struct sockaddr *)&from, - &fromlen); + newsock = accept(listen_socks[i], + (struct sockaddr *)&from, &fromlen); if (newsock < 0) { if (errno != EINTR && errno != EWOULDBLOCK) error("accept: %.100s", strerror(errno)); continue; } - if (fcntl(newsock, F_SETFL, 0) < 0) { - error("newsock del O_NONBLOCK: %s", strerror(errno)); + if (unset_nonblock(newsock) == -1) { close(newsock); continue; } @@ -1311,6 +1471,16 @@ main(int ac, char **av) continue; } + if (rexec_flag && socketpair(AF_UNIX, + SOCK_STREAM, 0, config_s) == -1) { + error("reexec socketpair: %s", + strerror(errno)); + close(newsock); + close(startup_p[0]); + close(startup_p[1]); + continue; + } + for (j = 0; j < options.max_startups; j++) if (startup_pipes[j] == -1) { startup_pipes[j] = startup_p[0]; @@ -1334,8 +1504,15 @@ main(int ac, char **av) close_listen_socks(); sock_in = newsock; sock_out = newsock; + close(startup_p[0]); + close(startup_p[1]); startup_pipe = -1; pid = getpid(); + if (rexec_flag) { + send_rexec_state(config_s[0], + &cfg); + close(config_s[0]); + } break; } else { /* @@ -1345,10 +1522,11 @@ main(int ac, char **av) */ if ((pid = fork()) == 0) { /* - * Child. Close the listening and max_startup - * sockets. Start using the accepted socket. - * Reinitialize logging (since our pid has - * changed). We break out of the loop to handle + * Child. Close the listening and + * max_startup sockets. Start using + * the accepted socket. Reinitialize + * logging (since our pid has changed). + * We break out of the loop to handle * the connection. */ startup_pipe = startup_p[1]; @@ -1356,7 +1534,12 @@ main(int ac, char **av) close_listen_socks(); sock_in = newsock; sock_out = newsock; - log_init(__progname, options.log_level, options.log_facility, log_stderr); + log_init(__progname, + options.log_level, + options.log_facility, + log_stderr); + if (rexec_flag) + close(config_s[0]); break; } } @@ -1369,18 +1552,25 @@ main(int ac, char **av) close(startup_p[1]); - /* Mark that the key has been used (it was "given" to the child). */ + if (rexec_flag) { + send_rexec_state(config_s[0], &cfg); + close(config_s[0]); + close(config_s[1]); + } + + /* + * Mark that the key has been used (it + * was "given" to the child). + */ if ((options.protocol & SSH_PROTO_1) && key_used == 0) { /* Schedule server key regeneration alarm. */ - mysignal(SIGALRM, key_regeneration_alarm); + signal(SIGALRM, key_regeneration_alarm); alarm(options.key_regeneration_time); key_used = 1; } arc4random_stir(); - - /* Close the new socket (the child is now taking care of it). */ close(newsock); } /* child process check (or debug mode) */ @@ -1390,6 +1580,7 @@ main(int ac, char **av) } /* This is the child processing a new connection. */ + setproctitle("%s", "[accepted]"); /* * Create a new session and process group since the 4.4BSD @@ -1406,6 +1597,46 @@ main(int ac, char **av) error("setsid: %.100s", strerror(errno)); #endif + if (rexec_flag) { + int fd; + + debug("rexec start in %d out %d newsock %d pipe %d sock %d", + sock_in, sock_out, newsock, startup_pipe, config_s[0]); + dup2(newsock, STDIN_FILENO); + dup2(STDIN_FILENO, STDOUT_FILENO); + if (startup_pipe == -1) + close(REEXEC_STARTUP_PIPE_FD); + else + dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); + + dup2(config_s[1], REEXEC_CONFIG_PASS_FD); + close(config_s[1]); + if (startup_pipe != -1) + close(startup_pipe); + + execv(rexec_argv[0], rexec_argv); + + /* Reexec has failed, fall back and continue */ + error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); + recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); + log_init(__progname, options.log_level, + options.log_facility, log_stderr); + + /* Clean up fds */ + startup_pipe = REEXEC_STARTUP_PIPE_FD; + close(config_s[1]); + close(REEXEC_CONFIG_PASS_FD); + newsock = sock_out = sock_in = dup(STDIN_FILENO); + if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { + dup2(fd, STDIN_FILENO); + dup2(fd, STDOUT_FILENO); + if (fd > STDERR_FILENO) + close(fd); + } + debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", + sock_in, sock_out, newsock, startup_pipe, config_s[0]); + } + /* * Disable the key regeneration alarm. We will not regenerate the * key since we are no longer in a position to give it to anyone. We @@ -1419,24 +1650,35 @@ main(int ac, char **av) signal(SIGCHLD, SIG_DFL); signal(SIGINT, SIG_DFL); - /* Set keepalives if requested. */ - if (options.keepalives && - setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, - sizeof(on)) < 0) - error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); - /* * Register our connection. This turns encryption off because we do * not have a key. */ packet_set_connection(sock_in, sock_out); + packet_set_server(); + + /* Set SO_KEEPALIVE if requested. */ + if (options.tcp_keep_alive && packet_connection_is_on_socket() && + setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) + error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); + + if ((remote_port = get_remote_port()) < 0) { + debug("get_remote_port failed"); + cleanup_exit(255); + } - remote_port = get_remote_port(); - remote_ip = get_remote_ipaddr(); + /* + * We use get_canonical_hostname with usedns = 0 instead of + * get_remote_ipaddr here so IP options will be checked. + */ + remote_ip = get_canonical_hostname(0); +#ifdef SSH_AUDIT_EVENTS + audit_connection_from(remote_ip, remote_port); +#endif #ifdef LIBWRAP /* Check whether logins are denied from this host. */ - { + if (packet_connection_is_on_socket()) { struct request_info req; request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); @@ -1455,61 +1697,44 @@ main(int ac, char **av) verbose("Connection from %.500s port %d", remote_ip, remote_port); /* - * We don\'t want to listen forever unless the other side + * We don't want to listen forever unless the other side * successfully authenticates itself. So we set up an alarm which is * cleared after successful authentication. A limit of zero - * indicates no limit. Note that we don\'t set the alarm in debugging + * indicates no limit. Note that we don't set the alarm in debugging * mode; it is just annoying to have the server exit just when you * are about to discover the bug. */ - mysignal(SIGALRM, grace_alarm_handler); + signal(SIGALRM, grace_alarm_handler); if (!debug_flag) alarm(options.login_grace_time); sshd_exchange_identification(sock_in, sock_out); - /* - * Check that the connection comes from a privileged port. - * Rhosts-Authentication only makes sense from privileged - * programs. Of course, if the intruder has root access on his local - * machine, he can connect from any port. So do not use these - * authentication methods from machines that you do not trust. - */ - if (options.rhosts_authentication && - (remote_port >= IPPORT_RESERVED || - remote_port < IPPORT_RESERVED / 2)) { - debug("Rhosts Authentication disabled, " - "originating port %d not trusted.", remote_port); - options.rhosts_authentication = 0; - } -#if defined(KRB4) && !defined(KRB5) - if (!packet_connection_is_ipv4() && - options.kerberos_authentication) { - debug("Kerberos Authentication disabled, only available for IPv4."); - options.kerberos_authentication = 0; - } -#endif /* KRB4 && !KRB5 */ -#ifdef AFS - /* If machine has AFS, set process authentication group. */ - if (k_hasafs()) { - k_setpag(); - k_unlog(); - } -#endif /* AFS */ packet_set_nonblocking(); + /* allocate authentication context */ + authctxt = xcalloc(1, sizeof(*authctxt)); + + authctxt->loginmsg = &loginmsg; + + /* XXX global for cleanup, access from other modules */ + the_authctxt = authctxt; + + /* prepare buffer to collect messages to display to user after login */ + buffer_init(&loginmsg); + if (use_privsep) - if ((authctxt = privsep_preauth()) != NULL) + if (privsep_preauth(authctxt) == 1) goto authenticated; /* perform the key exchange */ /* authenticate user and start session */ if (compat20) { do_ssh2_kex(); - authctxt = do_authentication2(); + do_authentication2(authctxt); } else { do_ssh1_kex(); - authctxt = do_authentication(); + do_authentication(authctxt); } /* * If we use privilege separation, the unprivileged child transfers @@ -1521,6 +1746,21 @@ main(int ac, char **av) } authenticated: + /* + * Cancel the alarm we set to limit the time taken for + * authentication. + */ + alarm(0); + signal(SIGALRM, SIG_DFL); + if (startup_pipe != -1) { + close(startup_pipe); + startup_pipe = -1; + } + +#ifdef SSH_AUDIT_EVENTS + audit_event(SSH_AUTH_SUCCESS); +#endif + /* * In privilege separation, we fork another child and prepare * file descriptor passing. @@ -1532,7 +1772,7 @@ main(int ac, char **av) destroy_sensitive_data(); } - /* Perform session preparation. */ + /* Start session. */ do_authenticated(authctxt); /* The connection has been terminated. */ @@ -1543,6 +1783,10 @@ main(int ac, char **av) finish_pam(); #endif /* USE_PAM */ +#ifdef SSH_AUDIT_EVENTS + PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); +#endif + packet_close(); if (use_privsep) @@ -1560,11 +1804,14 @@ ssh1_session_key(BIGNUM *session_key_int) { int rsafail = 0; - if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { + if (BN_cmp(sensitive_data.server_key->rsa->n, + sensitive_data.ssh1_host_key->rsa->n) > 0) { /* Server key has bigger modulus. */ if (BN_num_bits(sensitive_data.server_key->rsa->n) < - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { - fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + + SSH_KEY_BITS_RESERVED) { + fatal("do_connection: %s: " + "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", get_remote_ipaddr(), BN_num_bits(sensitive_data.server_key->rsa->n), BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), @@ -1579,8 +1826,10 @@ ssh1_session_key(BIGNUM *session_key_int) } else { /* Host key has bigger modulus (or they are equal). */ if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < - BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { - fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", + BN_num_bits(sensitive_data.server_key->rsa->n) + + SSH_KEY_BITS_RESERVED) { + fatal("do_connection: %s: " + "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", get_remote_ipaddr(), BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), BN_num_bits(sensitive_data.server_key->rsa->n), @@ -1652,24 +1901,10 @@ do_ssh1_kex(void) /* Declare supported authentication types. */ auth_mask = 0; - if (options.rhosts_authentication) - auth_mask |= 1 << SSH_AUTH_RHOSTS; if (options.rhosts_rsa_authentication) auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; if (options.rsa_authentication) auth_mask |= 1 << SSH_AUTH_RSA; -#if defined(KRB4) || defined(KRB5) - if (options.kerberos_authentication) - auth_mask |= 1 << SSH_AUTH_KERBEROS; -#endif -#if defined(AFS) || defined(KRB5) - if (options.kerberos_tgt_passing) - auth_mask |= 1 << SSH_PASS_KERBEROS_TGT; -#endif -#ifdef AFS - if (options.afs_token_passing) - auth_mask |= 1 << SSH_PASS_AFS_TOKEN; -#endif if (options.challenge_response_authentication == 1) auth_mask |= 1 << SSH_AUTH_TIS; if (options.password_authentication) @@ -1721,7 +1956,7 @@ do_ssh1_kex(void) if (!rsafail) { BN_mask_bits(session_key_int, sizeof(session_key) * 8); len = BN_num_bytes(session_key_int); - if (len < 0 || len > sizeof(session_key)) { + if (len < 0 || (u_int)len > sizeof(session_key)) { error("do_connection: bad session key len from %s: " "session_key_int %d > sizeof(session_key) %lu", get_remote_ipaddr(), len, (u_long)sizeof(session_key)); @@ -1731,9 +1966,10 @@ do_ssh1_kex(void) BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); - compute_session_id(session_id, cookie, + derive_ssh1_session_id( sensitive_data.ssh1_host_key->rsa->n, - sensitive_data.server_key->rsa->n); + sensitive_data.server_key->rsa->n, + cookie, session_id); /* * Xor the first 16 bytes of the session key with the * session id. @@ -1807,16 +2043,22 @@ do_ssh2_kex(void) myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; } - if (!options.compression) { + if (options.compression == COMP_NONE) { myproposal[PROPOSAL_COMP_ALGS_CTOS] = myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; + } else if (options.compression == COMP_DELAYED) { + myproposal[PROPOSAL_COMP_ALGS_CTOS] = + myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; } + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); /* start key exchange */ kex = kex_setup(myproposal); kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; + kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; + kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; kex->server = 1; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; @@ -1839,3 +2081,17 @@ do_ssh2_kex(void) #endif debug("KEX done"); } + +/* server specific fatal cleanup */ +void +cleanup_exit(int i) +{ + if (the_authctxt) + do_cleanup(the_authctxt); +#ifdef SSH_AUDIT_EVENTS + /* done after do_cleanup so it can cancel the PAM auth 'thread' */ + if (!use_privsep || mm_is_monitor()) + audit_event(SSH_CONNECTION_ABANDON); +#endif + _exit(i); +}