X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/d170feb1a17c020ae5b0a753096ef91dcabbb90a..8f73f7bbad3099712a0fdbc599a1b68058b12a3d:/sshd.c diff --git a/sshd.c b/sshd.c index 18df8ab8..47df9caf 100644 --- a/sshd.c +++ b/sshd.c @@ -42,7 +42,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.250 2002/06/23 10:29:52 deraadt Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.276 2003/08/28 12:54:34 markus 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 @@ -192,7 +188,7 @@ 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; @@ -202,8 +198,11 @@ int *startup_pipes = NULL; int startup_pipe; /* in child */ /* variables used for privilege separation */ -extern struct monitor *pmonitor; -extern int use_privsep; +int use_privsep; +struct monitor *pmonitor; + +/* message to be displayed after login */ +Buffer loginmsg; /* Prototypes for various functions defined later in this file. */ void destroy_sensitive_data(void); @@ -258,11 +257,11 @@ 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], + logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); exit(1); } @@ -303,11 +302,8 @@ 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()); } /* @@ -320,7 +316,7 @@ 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.", @@ -333,9 +329,9 @@ 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(); } @@ -374,39 +370,37 @@ 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)) { - log("Could not write ident string to %s", get_remote_ipaddr()); + /* 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()); + fatal_cleanup(); + } + + /* 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(); } - - /* 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", - 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; + 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 @@ -415,10 +409,10 @@ 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); - log("Bad protocol version identification '%.100s' from %s", + logit("Bad protocol version identification '%.100s' from %s", client_version_string, get_remote_ipaddr()); fatal_cleanup(); } @@ -427,8 +421,14 @@ 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(); } @@ -470,10 +470,10 @@ 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); - 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(); @@ -529,7 +529,8 @@ demote_sensitive_data(void) static void privsep_preauth_child(void) { - u_int32_t rand[256]; + u_int32_t rnd[256]; + gid_t gidset[1]; struct passwd *pw; int i; @@ -537,8 +538,8 @@ privsep_preauth_child(void) 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(); @@ -549,7 +550,7 @@ 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)); @@ -559,10 +560,18 @@ 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; @@ -578,6 +587,8 @@ 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); @@ -591,6 +602,10 @@ 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); } else { /* child */ @@ -613,7 +628,7 @@ privsep_postauth(Authctxt *authctxt) /* XXX - Remote port forwarding */ x_authctxt = authctxt; -#ifdef BROKEN_FD_PASSING +#ifdef DISABLE_FD_PASSING if (1) { #else if (authctxt->pw->pw_uid == 0 || options.use_login) { @@ -638,6 +653,8 @@ 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); monitor_child_postauth(pmonitor); @@ -790,7 +807,6 @@ 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; @@ -803,18 +819,27 @@ main(int ac, char **av) #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. */ + /* 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); /* 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:dDeiqtQ46")) != -1) { switch (opt) { case '4': IPv4or6 = AF_INET; @@ -826,15 +851,11 @@ main(int ac, char **av) 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; @@ -885,16 +906,15 @@ 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); + if (utmp_len > MAXHOSTNAMELEN) { + fprintf(stderr, "Invalid utmp length.\n"); + exit(1); + } break; case 'o': if (process_server_config_line(&options, optarg, @@ -919,9 +939,9 @@ 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! */ @@ -945,7 +965,8 @@ 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; @@ -976,15 +997,15 @@ 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); } @@ -1024,9 +1045,16 @@ main(int ac, char **av) (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) - fatal("Bad owner or mode for %s", - _PATH_PRIVSEP_CHROOT_DIR); +#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. */ @@ -1112,7 +1140,8 @@ 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)); @@ -1124,17 +1153,12 @@ 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); @@ -1150,7 +1174,7 @@ 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)); @@ -1185,7 +1209,10 @@ 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); } @@ -1226,7 +1253,7 @@ 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); @@ -1364,8 +1391,12 @@ 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 0 - /* XXX: this breaks Solaris */ +#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 @@ -1383,16 +1414,6 @@ 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, @@ -1441,37 +1462,12 @@ main(int ac, char **av) 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(); + /* prepare buffers to collect authentication messages */ + buffer_init(&loginmsg); + if (use_privsep) if ((authctxt = privsep_preauth()) != NULL) goto authenticated; @@ -1513,7 +1509,8 @@ 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(); @@ -1580,7 +1577,7 @@ 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 @@ -1593,9 +1590,9 @@ 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; } /* @@ -1625,24 +1622,10 @@ 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) @@ -1720,7 +1703,7 @@ 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); @@ -1788,6 +1771,8 @@ do_ssh2_kex(void) /* 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;