X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/4ac8556b9887a68b3752fd1e2de164e3dc1c76c5..0daa6547440ce987e35650166f45fb0b22635c40:/sshd.c diff --git a/sshd.c b/sshd.c index 0bd64477..bc458488 100644 --- a/sshd.c +++ b/sshd.c @@ -42,7 +42,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.241 2002/05/13 15:53:19 millert Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.268 2003/06/04 10:23:48 djm Exp $"); #include #include @@ -112,11 +112,7 @@ 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. */ -#ifdef IPV4_DEFAULT -int IPv4or6 = AF_INET; -#else int IPv4or6 = AF_UNSPEC; -#endif /* * Debug mode flag. This can be set on the command line. If debug @@ -202,8 +198,8 @@ int *startup_pipes = NULL; int startup_pipe; /* in child */ /* variables used for privilege separation */ -extern struct monitor *monitor; -extern int use_privsep; +int use_privsep; +struct monitor *pmonitor; /* Prototypes for various functions defined later in this file. */ void destroy_sensitive_data(void); @@ -219,6 +215,7 @@ static void close_listen_socks(void) { int i; + for (i = 0; i < num_listen_socks; i++) close(listen_socks[i]); num_listen_socks = -1; @@ -228,6 +225,7 @@ static void close_startup_pipes(void) { int i; + if (startup_pipes) for (i = 0; i < options.max_startups; i++) if (startup_pipes[i] != -1) @@ -256,11 +254,12 @@ sighup_handler(int sig) static void sighup_restart(void) { - log("Received SIGHUP; restarting."); + logit("Received SIGHUP; restarting."); close_listen_socks(); close_startup_pipes(); execv(saved_argv[0], saved_argv); - log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); + logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], + strerror(errno)); exit(1); } @@ -280,8 +279,8 @@ sigterm_handler(int sig) static void main_sigchld_handler(int sig) { - pid_t pid; int save_errno = errno; + pid_t pid; int status; while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || @@ -300,11 +299,8 @@ grace_alarm_handler(int sig) { /* XXX no idea how fix this signal handler */ - /* Close the connection. */ - packet_close(); - /* Log error and exit. */ - fatal("Timeout before authentication for %s.", get_remote_ipaddr()); + fatal("Timeout before authentication for %s", get_remote_ipaddr()); } /* @@ -317,7 +313,7 @@ grace_alarm_handler(int sig) static void generate_ephemeral_server_key(void) { - u_int32_t rand = 0; + u_int32_t rnd = 0; int i; verbose("Generating %s%d bit RSA key.", @@ -330,9 +326,9 @@ generate_ephemeral_server_key(void) for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { if (i % 4 == 0) - rand = arc4random(); - sensitive_data.ssh1_cookie[i] = rand & 0xff; - rand >>= 8; + rnd = arc4random(); + sensitive_data.ssh1_cookie[i] = rnd & 0xff; + rnd >>= 8; } arc4random_stir(); } @@ -341,6 +337,7 @@ static void key_regeneration_alarm(int sig) { int save_errno = errno; + signal(SIGALRM, SIG_DFL); errno = save_errno; key_do_regen = 1; @@ -372,17 +369,18 @@ sshd_exchange_identification(int sock_in, int sock_out) if (client_version_string == NULL) { /* Send our protocol version identification. */ - if (atomicio(write, sock_out, server_version_string, strlen(server_version_string)) + if (atomicio(write, sock_out, server_version_string, + strlen(server_version_string)) != strlen(server_version_string)) { - log("Could not write ident string to %s", get_remote_ipaddr()); + logit("Could not write ident string to %s", get_remote_ipaddr()); fatal_cleanup(); } - /* Read other side's version identification. */ + /* 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) { - log("Did not receive identification string from %s", + logit("Did not receive identification string from %s", get_remote_ipaddr()); fatal_cleanup(); } @@ -413,7 +411,7 @@ sshd_exchange_identification(int sock_in, int sock_out) (void) atomicio(write, sock_out, s, strlen(s)); close(sock_in); close(sock_out); - log("Bad protocol version identification '%.100s' from %s", + logit("Bad protocol version identification '%.100s' from %s", client_version_string, get_remote_ipaddr()); fatal_cleanup(); } @@ -422,8 +420,14 @@ sshd_exchange_identification(int sock_in, int sock_out) compat_datafellows(remote_version); + if (datafellows & SSH_BUG_PROBE) { + logit("probed from %s with %s. Don't panic.", + get_remote_ipaddr(), client_version_string); + fatal_cleanup(); + } + if (datafellows & SSH_BUG_SCANNER) { - log("scanned from %s with %s. Don't panic.", + logit("scanned from %s with %s. Don't panic.", get_remote_ipaddr(), client_version_string); fatal_cleanup(); } @@ -468,14 +472,13 @@ sshd_exchange_identification(int sock_in, int sock_out) (void) atomicio(write, sock_out, s, strlen(s)); close(sock_in); close(sock_out); - log("Protocol major versions differ for %s: %.200s vs. %.200s", + logit("Protocol major versions differ for %s: %.200s vs. %.200s", get_remote_ipaddr(), server_version_string, client_version_string); fatal_cleanup(); } } - /* Destroy the host and server keys. They will no longer be needed. */ void destroy_sensitive_data(void) @@ -525,16 +528,17 @@ demote_sensitive_data(void) static void privsep_preauth_child(void) { - u_int32_t rand[256]; - int i; + u_int32_t rnd[256]; + gid_t gidset[1]; struct passwd *pw; + int i; /* Enable challenge-response authentication for privilege separation */ privsep_challenge_enable(); for (i = 0; i < 256; i++) - rand[i] = arc4random(); - RAND_seed(rand, sizeof(rand)); + rnd[i] = arc4random(); + RAND_seed(rnd, sizeof(rnd)); /* Demote the private keys to public keys. */ demote_sensitive_data(); @@ -545,7 +549,7 @@ privsep_preauth_child(void) memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); endpwent(); - /* Change our root directory*/ + /* Change our root directory */ if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, strerror(errno)); @@ -555,10 +559,18 @@ privsep_preauth_child(void) /* Drop our privileges */ 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 */ do_setusercontext(pw); +#else + gidset[0] = pw->pw_gid; + if (setgroups(1, gidset) < 0) + fatal("setgroups: %.100s", strerror(errno)); + permanently_set_uid(pw); +#endif } -static Authctxt* +static Authctxt * privsep_preauth(void) { Authctxt *authctxt = NULL; @@ -566,32 +578,38 @@ privsep_preauth(void) pid_t pid; /* Set up unprivileged child process to deal with network data */ - monitor = monitor_init(); + pmonitor = monitor_init(); /* Store a pointer to the kex for later rekeying */ - monitor->m_pkex = &xxx_kex; + pmonitor->m_pkex = &xxx_kex; pid = fork(); if (pid == -1) { fatal("fork of unprivileged child failed"); } else if (pid != 0) { - debug2("Network child is on pid %d", pid); + fatal_remove_cleanup((void (*) (void *)) packet_close, NULL); + + debug2("Network child is on pid %ld", (long)pid); - close(monitor->m_recvfd); - authctxt = monitor_child_preauth(monitor); - close(monitor->m_sendfd); + close(pmonitor->m_recvfd); + authctxt = monitor_child_preauth(pmonitor); + close(pmonitor->m_sendfd); /* Sync memory */ - monitor_sync(monitor); + monitor_sync(pmonitor); /* Wait for the child's exit status */ 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); } else { /* child */ - close(monitor->m_sendfd); + close(pmonitor->m_sendfd); /* Demote the child */ if (getuid() == 0 || geteuid() == 0) @@ -609,9 +627,13 @@ privsep_postauth(Authctxt *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(monitor); + monitor_apply_keystate(pmonitor); use_privsep = 0; return; } @@ -624,21 +646,23 @@ privsep_postauth(Authctxt *authctxt) } /* New socket pair */ - monitor_reinit(monitor); + monitor_reinit(pmonitor); - monitor->m_pid = fork(); - if (monitor->m_pid == -1) + pmonitor->m_pid = fork(); + if (pmonitor->m_pid == -1) fatal("fork of unprivileged child failed"); - else if (monitor->m_pid != 0) { - debug2("User child is on pid %d", monitor->m_pid); - close(monitor->m_recvfd); - monitor_child_postauth(monitor); + 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); + monitor_child_postauth(pmonitor); /* NEVERREACHED */ exit(0); } - close(monitor->m_sendfd); + close(pmonitor->m_sendfd); /* Demote the private keys to public keys. */ demote_sensitive_data(); @@ -647,7 +671,7 @@ privsep_postauth(Authctxt *authctxt) do_setusercontext(authctxt->pw); /* It is safe now to apply the key state */ - monitor_apply_keystate(monitor); + monitor_apply_keystate(pmonitor); } static char * @@ -683,6 +707,7 @@ Key * get_hostkey_by_type(int type) { int i; + for (i = 0; i < options.num_host_key_files; i++) { Key *key = sensitive_data.host_keys[i]; if (key != NULL && key->type == type) @@ -703,6 +728,7 @@ int get_hostkey_index(Key *key) { int i; + for (i = 0; i < options.num_host_key_files; i++) { if (key == sensitive_data.host_keys[i]) return (i); @@ -780,7 +806,6 @@ main(int ac, char **av) const char *remote_ip; int remote_port; FILE *f; - struct linger linger; struct addrinfo *ai; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; int listen_sock, maxfd; @@ -796,9 +821,18 @@ main(int ac, char **av) __progname = get_progname(av[0]); init_rng(); - /* Save argv. */ + /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ saved_argc = ac; - saved_argv = av; + saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); + for (i = 0; i < ac; i++) + saved_argv[i] = xstrdup(av[i]); + saved_argv[i] = NULL; + +#ifndef HAVE_SETPROCTITLE + /* Prepare for later setproctitle emulation */ + compat_init_setproctitle(ac, av); + av = saved_argv; +#endif /* Initialize configuration options to their default values. */ initialize_server_options(&options); @@ -885,6 +919,10 @@ main(int ac, char **av) break; case 'u': utmp_len = atoi(optarg); + if (utmp_len > MAXHOSTNAMELEN) { + fprintf(stderr, "Invalid utmp length.\n"); + exit(1); + } break; case 'o': if (process_server_config_line(&options, optarg, @@ -909,9 +947,9 @@ main(int ac, char **av) SYSLOG_LEVEL_INFO : options.log_level, options.log_facility == SYSLOG_FACILITY_NOT_SET ? SYSLOG_FACILITY_AUTH : options.log_facility, - !inetd_flag); + log_stderr || !inetd_flag); -#ifdef _CRAY +#ifdef _UNICOS /* Cray can define user privs drop all prives now! * Not needed on PRIV_SU systems! */ @@ -935,7 +973,8 @@ main(int ac, char **av) debug("sshd version %.100s", SSH_VERSION); /* load private host keys */ - sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*)); + 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; @@ -966,15 +1005,15 @@ main(int ac, char **av) key_type(key)); } if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { - log("Disabling protocol version 1. Could not load host key"); + logit("Disabling protocol version 1. Could not load host key"); options.protocol &= ~SSH_PROTO_1; } if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { - log("Disabling protocol version 2. Could not load host key"); + logit("Disabling protocol version 2. Could not load host key"); options.protocol &= ~SSH_PROTO_2; } if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { - log("sshd: no hostkeys available -- exiting."); + logit("sshd: no hostkeys available -- exiting."); exit(1); } @@ -991,16 +1030,41 @@ main(int ac, char **av) * hate software patents. I dont know if this can go? Niels */ if (options.server_key_bits > - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED && - options.server_key_bits < - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - + SSH_KEY_BITS_RESERVED && options.server_key_bits < + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + + SSH_KEY_BITS_RESERVED) { options.server_key_bits = - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED; + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + + SSH_KEY_BITS_RESERVED; debug("Forcing server key to %d bits to make it differ from host key.", options.server_key_bits); } } + if (use_privsep) { + struct passwd *pw; + struct stat st; + + if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) + fatal("Privilege separation user %s does not exist", + SSH_PRIVSEP_USER); + if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || + (S_ISDIR(st.st_mode) == 0)) + fatal("Missing privilege separation directory: %s", + _PATH_PRIVSEP_CHROOT_DIR); + +#ifdef HAVE_CYGWIN + if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && + (st.st_uid != getuid () || + (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) +#else + if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) +#endif + fatal("%s must be owned by root and not group or " + "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); + } + /* Configuration looks good, so exit if in test mode. */ if (test_flag) exit(0); @@ -1084,7 +1148,8 @@ main(int ac, char **av) continue; } /* Create socket for listening. */ - listen_sock = socket(ai->ai_family, SOCK_STREAM, 0); + listen_sock = socket(ai->ai_family, ai->ai_socktype, + ai->ai_protocol); if (listen_sock < 0) { /* kernel may not support ipv6 */ verbose("socket: %.100s", strerror(errno)); @@ -1096,17 +1161,12 @@ main(int ac, char **av) continue; } /* - * Set socket options. We try to make the port - * reusable and have it close as fast as possible - * without waiting in unnecessary wait states on - * close. + * Set socket options. + * Allow local port reuse in TIME_WAIT. */ - setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, - &on, sizeof(on)); - linger.l_onoff = 1; - linger.l_linger = 5; - setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, - &linger, sizeof(linger)); + if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, + &on, sizeof(on)) == -1) + error("setsockopt SO_REUSEADDR: %s", strerror(errno)); debug("Bind to port %s on %s.", strport, ntop); @@ -1122,7 +1182,7 @@ main(int ac, char **av) num_listen_socks++; /* Start listening on the port. */ - log("Server listening on %s port %s.", ntop, strport); + logit("Server listening on %s port %s.", ntop, strport); if (listen(listen_sock, 5) < 0) fatal("listen: %.100s", strerror(errno)); @@ -1158,7 +1218,7 @@ main(int ac, char **av) */ f = fopen(options.pid_file, "wb"); if (f) { - fprintf(f, "%u\n", (u_int) getpid()); + fprintf(f, "%ld\n", (long) getpid()); fclose(f); } } @@ -1198,7 +1258,7 @@ main(int ac, char **av) if (ret < 0 && errno != EINTR) error("select: %.100s", strerror(errno)); if (received_sigterm) { - log("Received signal %d; terminating.", + logit("Received signal %d; terminating.", (int) received_sigterm); close_listen_socks(); unlink(options.pid_file); @@ -1305,7 +1365,7 @@ main(int ac, char **av) if (pid < 0) error("fork: %.100s", strerror(errno)); else - debug("Forked child %d.", pid); + debug("Forked child %ld.", (long)pid); close(startup_p[1]); @@ -1313,7 +1373,7 @@ main(int ac, char **av) if ((options.protocol & SSH_PROTO_1) && key_used == 0) { /* Schedule server key regeneration alarm. */ - signal(SIGALRM, key_regeneration_alarm); + mysignal(SIGALRM, key_regeneration_alarm); alarm(options.key_regeneration_time); key_used = 1; } @@ -1336,8 +1396,15 @@ main(int ac, char **av) * setlogin() affects the entire process group. We don't * want the child to be able to affect the parent. */ - if (setsid() < 0) +#if !defined(SSHD_ACQUIRES_CTTY) + /* + * If setsid is called, on some platforms sshd will later acquire a + * controlling terminal which will result in "could not set + * controlling tty" errors. + */ + if (!debug_flag && !inetd_flag && setsid() < 0) error("setsid: %.100s", strerror(errno)); +#endif /* * Disable the key regeneration alarm. We will not regenerate the @@ -1352,16 +1419,6 @@ main(int ac, char **av) signal(SIGCHLD, SIG_DFL); signal(SIGINT, SIG_DFL); - /* - * Set socket options for the connection. We want the socket to - * close as fast as possible without waiting for anything. If the - * connection is not a socket, these will do nothing. - */ - /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ - linger.l_onoff = 1; - linger.l_linger = 5; - setsockopt(sock_in, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger)); - /* Set keepalives if requested. */ if (options.keepalives && setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, @@ -1405,14 +1462,14 @@ main(int ac, char **av) * mode; it is just annoying to have the server exit just when you * are about to discover the bug. */ - signal(SIGALRM, grace_alarm_handler); + mysignal(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 priviledged + * 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. @@ -1459,7 +1516,7 @@ main(int ac, char **av) * the current keystate and exits */ if (use_privsep) { - mm_send_keystate(monitor); + mm_send_keystate(pmonitor); exit(0); } @@ -1482,7 +1539,8 @@ main(int ac, char **av) verbose("Closing connection to %.100s", remote_ip); #ifdef USE_PAM - finish_pam(); + if (options.use_pam) + finish_pam(); #endif /* USE_PAM */ packet_close(); @@ -1549,7 +1607,7 @@ do_ssh1_kex(void) u_char session_key[SSH_SESSION_KEY_LENGTH]; u_char cookie[8]; u_int cipher_type, auth_mask, protocol_flags; - u_int32_t rand = 0; + u_int32_t rnd = 0; /* * Generate check bytes that the client must send back in the user @@ -1562,9 +1620,9 @@ do_ssh1_kex(void) */ for (i = 0; i < 8; i++) { if (i % 4 == 0) - rand = arc4random(); - cookie[i] = rand & 0xff; - rand >>= 8; + rnd = arc4random(); + cookie[i] = rnd & 0xff; + rnd >>= 8; } /* @@ -1689,7 +1747,7 @@ do_ssh1_kex(void) u_char *buf = xmalloc(bytes); MD5_CTX md; - log("do_connection: generating a fake encryption key"); + logit("do_connection: generating a fake encryption key"); BN_bn2bin(session_key_int, buf); MD5_Init(&md); MD5_Update(&md, buf, bytes); @@ -1722,7 +1780,7 @@ do_ssh1_kex(void) debug("Received session key; encryption turned on."); - /* Send an acknowledgement packet. Note that this packet is sent encrypted. */ + /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ packet_start(SSH_SMSG_SUCCESS); packet_send(); packet_write_wait(); @@ -1749,10 +1807,16 @@ do_ssh2_kex(void) myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; } + if (!options.compression) { + myproposal[PROPOSAL_COMP_ALGS_CTOS] = + myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; + } 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_GEX_SHA1] = kexgex_server; kex->server = 1; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string;