X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/6ff58a4b6c79ef855081d51fb28d4827a29524bb..31b41ceb9541ae922669644dbec216630874a208:/sshd.c diff --git a/sshd.c b/sshd.c index 6169a733..89f36a47 100644 --- a/sshd.c +++ b/sshd.c @@ -42,7 +42,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.287 2004/02/25 00:22:45 djm Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.305 2004/12/23 23:11:00 djm Exp $"); #include #include @@ -60,12 +60,12 @@ RCSID("$OpenBSD: sshd.c,v 1.287 2004/02/25 00:22:45 djm Exp $"); #include "rsa.h" #include "sshpty.h" #include "packet.h" -#include "mpaux.h" #include "log.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" #include "buffer.h" +#include "bufaux.h" #include "cipher.h" #include "kex.h" #include "key.h" @@ -77,6 +77,7 @@ RCSID("$OpenBSD: sshd.c,v 1.287 2004/02/25 00:22:45 djm Exp $"); #include "canohost.h" #include "auth.h" #include "misc.h" +#include "msg.h" #include "dispatch.h" #include "channels.h" #include "session.h" @@ -96,12 +97,13 @@ 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 -extern char **environ; /* Server configuration options. */ ServerOptions options; @@ -109,12 +111,6 @@ 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 @@ -139,6 +135,12 @@ 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. @@ -202,12 +204,12 @@ int startup_pipe; /* in child */ int use_privsep; struct monitor *pmonitor = NULL; -/* message to be displayed after login */ -Buffer loginmsg; - /* 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); void demote_sensitive_data(void); @@ -651,6 +653,7 @@ privsep_postauth(Authctxt *authctxt) else if (pmonitor->m_pid != 0) { debug2("User child is on pid %ld", (long)pmonitor->m_pid); close(pmonitor->m_recvfd); + buffer_clear(&loginmsg); monitor_child_postauth(pmonitor); /* NEVERREACHED */ @@ -741,7 +744,7 @@ 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; @@ -752,41 +755,107 @@ 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, %s\n", - SSH_VERSION, SSLeay_version(SSLEAY_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 " + */ + 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); + + 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); + } + buffer_free(&m); + + debug3("%s: done", __func__); +} + /* * Main program for the daemon. */ @@ -795,7 +864,8 @@ 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, fdsetsz, on = 1; + int sock_in = -1, sock_out = -1, newsock = -1; pid_t pid; socklen_t fromlen; fd_set *fdset; @@ -807,11 +877,12 @@ main(int ac, char **av) 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; Key *key; Authctxt *authctxt; int ret, key_used = 0; + Buffer cfg; #ifdef HAVE_SECUREWARE (void)set_auth_parameters(ac, av); @@ -821,6 +892,7 @@ main(int ac, char **av) /* 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]); @@ -832,17 +904,20 @@ main(int ac, char **av) av = saved_argv; #endif + if (geteuid() == 0 && setgroups(0, NULL) == -1) + debug("setgroups(): %.200s", strerror(errno)); + /* 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: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; @@ -863,6 +938,13 @@ 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; @@ -926,8 +1008,16 @@ 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 @@ -940,8 +1030,15 @@ main(int ac, char **av) SYSLOG_FACILITY_AUTH : options.log_facility, log_stderr || !inetd_flag); +#ifdef _AIX + /* + * Unset KRB5CCNAME, otherwise the user's session may inherit it from + * root's environment + */ + unsetenv("KRB5CCNAME"); +#endif /* _AIX */ #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(); @@ -949,29 +1046,43 @@ main(int ac, char **av) seed_rng(); - /* Read server configuration options from the configuration file. */ - read_server_config(&options, config_file_name); + 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); + + parse_server_config(&options, + rexeced_flag ? "rexec" : config_file_name, &cfg); + + if (!rexec_flag) + buffer_free(&cfg); /* 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 * 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); @@ -1070,6 +1181,16 @@ main(int ac, char **av) if (setgroups(0, NULL) < 0) debug("setgroups() failed: %.200s", strerror(errno)); + if (rexec_flag) { + rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2)); + 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) log_stderr = 1; @@ -1106,29 +1227,39 @@ main(int ac, char **av) unmounted if desired. */ chdir("/"); -#ifndef HAVE_CYGWIN - /* Clear environment */ - environ[0] = NULL; -#endif - /* ignore SIGPIPE */ signal(SIGPIPE, SIG_IGN); /* 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) { @@ -1151,8 +1282,7 @@ 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; } @@ -1295,8 +1425,7 @@ main(int ac, char **av) 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; } @@ -1310,6 +1439,16 @@ 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]; @@ -1333,8 +1472,15 @@ 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 { /* @@ -1356,6 +1502,8 @@ main(int ac, char **av) sock_in = newsock; sock_out = newsock; log_init(__progname, options.log_level, options.log_facility, log_stderr); + if (rexec_flag) + close(config_s[0]); break; } } @@ -1368,6 +1516,12 @@ main(int ac, char **av) close(startup_p[1]); + 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) { @@ -1389,6 +1543,7 @@ 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 @@ -1405,6 +1560,46 @@ 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 @@ -1435,7 +1630,7 @@ main(int ac, char **av) #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); @@ -1483,6 +1678,9 @@ main(int ac, char **av) if (privsep_preauth(authctxt) == 1) goto authenticated; + /* prepare buffer to collect messages to display to user after login */ + buffer_init(&loginmsg); + /* perform the key exchange */ /* authenticate user and start session */ if (compat20) { @@ -1698,9 +1896,10 @@ 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. @@ -1783,6 +1982,7 @@ do_ssh2_kex(void) /* 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->server = 1; kex->client_version_string=client_version_string;