X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5b84789fdd5dda5bb489a8f0486f983799b16978..HEAD:/sshd.c diff --git a/sshd.c b/sshd.c index ee588ff8..bf2e76cc 100644 --- a/sshd.c +++ b/sshd.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshd.c,v 1.347 2006/08/18 09:15:20 markus Exp $ */ +/* $OpenBSD: sshd.c,v 1.372 2010/01/29 00:20:41 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -54,6 +54,7 @@ # include #endif #include "openbsd-compat/sys-tree.h" +#include "openbsd-compat/sys-queue.h" #include #include @@ -65,6 +66,7 @@ #include #include #include +#include #include #include #include @@ -74,6 +76,8 @@ #include #include #include +#include "openbsd-compat/openssl-compat.h" + #ifdef HAVE_SECUREWARE #include #include @@ -113,14 +117,14 @@ #include "ssh-gss.h" #endif #include "monitor_wrap.h" -#include "monitor_fdpass.h" +#include "roaming.h" #include "version.h" #ifdef LIBWRAP #include #include -int allow_severity = LOG_INFO; -int deny_severity = LOG_WARNING; +int allow_severity; +int deny_severity; #endif /* LIBWRAP */ #ifndef O_NOCTTY @@ -243,6 +247,9 @@ Buffer cfg; /* message to be displayed after login */ Buffer loginmsg; +/* Unprivileged user */ +struct passwd *privsep_pw = NULL; + /* Prototypes for various functions defined later in this file. */ void destroy_sensitive_data(void); void demote_sensitive_data(void); @@ -301,6 +308,8 @@ sighup_restart(void) logit("Received SIGHUP; restarting."); close_listen_socks(); close_startup_pipes(); + alarm(0); /* alarm timer persists across exec */ + signal(SIGHUP, SIG_IGN); /* will be restored after exec */ execv(saved_argv[0], saved_argv); logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); @@ -361,9 +370,6 @@ grace_alarm_handler(int sig) static void generate_ephemeral_server_key(void) { - u_int32_t rnd = 0; - int i; - verbose("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "", options.server_key_bits); if (sensitive_data.server_key != NULL) @@ -372,12 +378,7 @@ generate_ephemeral_server_key(void) options.server_key_bits); verbose("RSA key generation complete."); - for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { - if (i % 4 == 0) - rnd = arc4random(); - sensitive_data.ssh1_cookie[i] = rnd & 0xff; - rnd >>= 8; - } + arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); arc4random_stir(); } @@ -399,7 +400,7 @@ sshd_exchange_identification(int sock_in, int sock_out) int mismatch; int remote_major, remote_minor; int major, minor; - char *s; + char *s, *newline = "\n"; char buf[256]; /* Must not be larger than remote_version. */ char remote_version[256]; /* Must be at least as big as buf. */ @@ -410,15 +411,17 @@ sshd_exchange_identification(int sock_in, int sock_out) } else if (options.protocol & SSH_PROTO_2) { major = PROTOCOL_MAJOR_2; minor = PROTOCOL_MINOR_2; + newline = "\r\n"; } else { major = PROTOCOL_MAJOR_1; minor = PROTOCOL_MINOR_1; } - snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); + snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor, + SSH_VERSION, newline); server_version_string = xstrdup(buf); /* Send our protocol version identification. */ - if (atomicio(vwrite, sock_out, server_version_string, + if (roaming_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()); @@ -428,7 +431,7 @@ sshd_exchange_identification(int sock_in, int sock_out) /* 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) { + if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) { logit("Did not receive identification string from %s", get_remote_ipaddr()); cleanup_exit(255); @@ -578,25 +581,17 @@ privsep_preauth_child(void) { 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++) - rnd[i] = arc4random(); + arc4random_stir(); + arc4random_buf(rnd, sizeof(rnd)); RAND_seed(rnd, sizeof(rnd)); /* Demote the private keys to public keys. */ demote_sensitive_data(); - if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) - fatal("Privilege separation user %s does not exist", - SSH_PRIVSEP_USER); - memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); - endpwent(); - /* Change our root directory */ if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, @@ -605,16 +600,16 @@ privsep_preauth_child(void) fatal("chdir(\"/\"): %s", strerror(errno)); /* Drop our privileges */ - debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, - (u_int)pw->pw_gid); + debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, + (u_int)privsep_pw->pw_gid); #if 0 /* XXX not ready, too heavy after chroot */ - do_setusercontext(pw); + do_setusercontext(privsep_pw); #else - gidset[0] = pw->pw_gid; + gidset[0] = privsep_pw->pw_gid; if (setgroups(1, gidset) < 0) fatal("setgroups: %.100s", strerror(errno)); - permanently_set_uid(pw); + permanently_set_uid(privsep_pw); #endif } @@ -664,6 +659,8 @@ privsep_preauth(Authctxt *authctxt) static void privsep_postauth(Authctxt *authctxt) { + u_int32_t rnd[256]; + #ifdef DISABLE_FD_PASSING if (1) { #else @@ -681,7 +678,7 @@ privsep_postauth(Authctxt *authctxt) if (pmonitor->m_pid == -1) fatal("fork of unprivileged child failed"); else if (pmonitor->m_pid != 0) { - debug2("User child is on pid %ld", (long)pmonitor->m_pid); + verbose("User child is on pid %ld", (long)pmonitor->m_pid); close(pmonitor->m_recvfd); buffer_clear(&loginmsg); monitor_child_postauth(pmonitor); @@ -695,6 +692,10 @@ privsep_postauth(Authctxt *authctxt) /* Demote the private keys to public keys. */ demote_sensitive_data(); + arc4random_stir(); + arc4random_buf(rnd, sizeof(rnd)); + RAND_seed(rnd, sizeof(rnd)); + /* Drop privileges */ do_setusercontext(authctxt->pw); @@ -794,7 +795,7 @@ drop_connection(int startups) p *= startups - options.max_startups_begin; p /= options.max_startups - options.max_startups_begin; p += options.max_startups_rate; - r = arc4random() % 100; + r = arc4random_uniform(100); debug("drop_connection: p %d, r %d", p, r); return (r < p) ? 1 : 0; @@ -806,8 +807,9 @@ usage(void) 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" +"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" +" [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" +" [-o option] [-p port] [-u len]\n" ); exit(1); } @@ -955,8 +957,7 @@ server_listen(void) ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { error("getnameinfo failed: %.100s", - (ret != EAI_SYSTEM) ? gai_strerror(ret) : - strerror(errno)); + ssh_gai_strerror(ret)); continue; } /* Create socket for listening. */ @@ -979,6 +980,10 @@ server_listen(void) &on, sizeof(on)) == -1) error("setsockopt SO_REUSEADDR: %s", strerror(errno)); + /* Only communicate in IPv6 over AF_INET6 sockets. */ + if (ai->ai_family == AF_INET6) + sock_set_v6only(listen_sock); + debug("Bind to port %s on %s.", strport, ntop); /* Bind the socket to the desired port. */ @@ -1086,7 +1091,8 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) *newsock = accept(listen_socks[i], (struct sockaddr *)&from, &fromlen); if (*newsock < 0) { - if (errno != EINTR && errno != EWOULDBLOCK) + if (errno != EINTR && errno != EAGAIN && + errno != EWOULDBLOCK) error("accept: %.100s", strerror(errno)); continue; } @@ -1233,9 +1239,12 @@ main(int ac, char **av) int opt, i, on = 1; int sock_in = -1, sock_out = -1, newsock = -1; const char *remote_ip; + char *test_user = NULL, *test_host = NULL, *test_addr = NULL; int remote_port; - char *line; + char *line, *p, *cp; int config_s[2] = { -1 , -1 }; + u_int64_t ibytes, obytes; + mode_t new_umask; Key *key; Authctxt *authctxt; @@ -1269,7 +1278,7 @@ main(int ac, char **av) initialize_server_options(&options); /* Parse command-line arguments. */ - while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { + while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) { switch (opt) { case '4': options.address_family = AF_INET; @@ -1320,7 +1329,7 @@ main(int ac, char **av) exit(1); } options.ports[options.num_ports++] = a2port(optarg); - if (options.ports[options.num_ports-1] == 0) { + if (options.ports[options.num_ports-1] <= 0) { fprintf(stderr, "Bad port number.\n"); exit(1); } @@ -1342,11 +1351,31 @@ main(int ac, char **av) fprintf(stderr, "too many host keys.\n"); exit(1); } - options.host_key_files[options.num_host_key_files++] = optarg; + options.host_key_files[options.num_host_key_files++] = + derelativise_path(optarg); break; case 't': test_flag = 1; break; + case 'T': + test_flag = 2; + break; + case 'C': + cp = optarg; + while ((p = strsep(&cp, ",")) && *p != '\0') { + if (strncmp(p, "addr=", 5) == 0) + test_addr = xstrdup(p + 5); + else if (strncmp(p, "host=", 5) == 0) + test_host = xstrdup(p + 5); + else if (strncmp(p, "user=", 5) == 0) + test_user = xstrdup(p + 5); + else { + fprintf(stderr, "Invalid test " + "mode specification %s\n", p); + exit(1); + } + } + break; case 'u': utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); if (utmp_len > MAXHOSTNAMELEN) { @@ -1369,7 +1398,7 @@ main(int ac, char **av) } if (rexeced_flag || inetd_flag) rexec_flag = 0; - if (rexec_flag && (av[0] == NULL || *av[0] != '/')) + if (!test_flag && (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); @@ -1408,6 +1437,21 @@ main(int ac, char **av) sensitive_data.have_ssh1_key = 0; sensitive_data.have_ssh2_key = 0; + /* + * If we're doing an extended config test, make sure we have all of + * the parameters we need. If we're not doing an extended test, + * do not silently ignore connection test params. + */ + if (test_flag >= 2 && + (test_user != NULL || test_host != NULL || test_addr != NULL) + && (test_user == NULL || test_host == NULL || test_addr == NULL)) + fatal("user, host and addr are all required when testing " + "Match configs"); + if (test_flag < 2 && (test_user != NULL || test_host != NULL || + test_addr != NULL)) + fatal("Config test connection parameter (-C) provided without " + "test mode (-T)"); + /* Fetch our configuration */ buffer_init(&cfg); if (rexeced_flag) @@ -1423,6 +1467,10 @@ main(int ac, char **av) /* Fill in default values for those options not explicitly set. */ fill_default_server_options(&options); + /* challenge-response is implemented via keyboard interactive */ + if (options.challenge_response_authentication) + options.kbd_interactive_authentication = 1; + /* set default channel AF */ channel_set_af(options.address_family); @@ -1434,6 +1482,19 @@ main(int ac, char **av) debug("sshd version %.100s", SSH_RELEASE); + /* Store privilege separation user for later use if required. */ + if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { + if (use_privsep || options.kerberos_authentication) + fatal("Privilege separation user %s does not exist", + SSH_PRIVSEP_USER); + } else { + memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd)); + privsep_pw = pwcopy(privsep_pw); + xfree(privsep_pw->pw_passwd); + privsep_pw->pw_passwd = xstrdup("*"); + } + endpwent(); + /* load private host keys */ sensitive_data.host_keys = xcalloc(options.num_host_key_files, sizeof(Key *)); @@ -1503,9 +1564,6 @@ main(int ac, char **av) if (use_privsep) { struct stat st; - 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) || (S_ISDIR(st.st_mode) == 0)) fatal("Missing privilege separation directory: %s", @@ -1522,6 +1580,13 @@ main(int ac, char **av) "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); } + if (test_flag > 1) { + if (test_user != NULL && test_addr != NULL && test_host != NULL) + parse_server_match_config(&options, test_user, + test_host, test_addr); + dump_config(&options); + } + /* Configuration looks good, so exit if in test mode. */ if (test_flag) exit(0); @@ -1546,6 +1611,10 @@ main(int ac, char **av) rexec_argv[rexec_argc + 1] = NULL; } + /* Ensure that umask disallows at least group and world write */ + new_umask = umask(0077) | 0022; + (void) umask(new_umask); + /* Initialize the log (it is reinitialized below in case we forked). */ if (debug_flag && (!inetd_flag || rexeced_flag)) log_stderr = 1; @@ -1588,11 +1657,8 @@ main(int ac, char **av) /* Get a connection, either from inetd or a listening TCP socket */ if (inetd_flag) { server_accept_inetd(&sock_in, &sock_out); - - if ((options.protocol & SSH_PROTO_1) && - sensitive_data.server_key == NULL) - generate_ephemeral_server_key(); } else { + platform_pre_listen(); server_listen(); if (options.protocol & SSH_PROTO_1) @@ -1682,6 +1748,10 @@ main(int ac, char **av) sock_in, sock_out, newsock, startup_pipe, config_s[0]); } + /* Executed child processes don't need these. */ + fcntl(sock_out, F_SETFD, FD_CLOEXEC); + fcntl(sock_in, F_SETFD, FD_CLOEXEC); + /* * 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 @@ -1728,6 +1798,8 @@ main(int ac, char **av) audit_connection_from(remote_ip, remote_port); #endif #ifdef LIBWRAP + allow_severity = options.log_facility|LOG_INFO; + deny_severity = options.log_facility|LOG_WARNING; /* Check whether logins are denied from this host. */ if (packet_connection_is_on_socket()) { struct request_info req; @@ -1761,6 +1833,10 @@ main(int ac, char **av) sshd_exchange_identification(sock_in, sock_out); + /* In inetd mode, generate ephemeral key only for proto 1 connections */ + if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) + generate_ephemeral_server_key(); + packet_set_nonblocking(); /* allocate authentication context */ @@ -1813,6 +1889,20 @@ main(int ac, char **av) audit_event(SSH_AUTH_SUCCESS); #endif +#ifdef GSSAPI + if (options.gss_authentication) { + temporarily_use_uid(authctxt->pw); + ssh_gssapi_storecreds(); + restore_uid(); + } +#endif +#ifdef USE_PAM + if (options.use_pam) { + do_pam_setcred(1); + do_pam_session(); + } +#endif + /* * In privilege separation, we fork another child and prepare * file descriptor passing. @@ -1824,11 +1914,18 @@ main(int ac, char **av) destroy_sensitive_data(); } + packet_set_timeout(options.client_alive_interval, + options.client_alive_count_max); + /* Start session. */ do_authenticated(authctxt); /* The connection has been terminated. */ - verbose("Closing connection to %.100s", remote_ip); + packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); + packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); + verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes); + + verbose("Closing connection to %.500s port %d", remote_ip, remote_port); #ifdef USE_PAM if (options.use_pam) @@ -1908,7 +2005,6 @@ 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 rnd = 0; /* * Generate check bytes that the client must send back in the user @@ -1919,12 +2015,7 @@ do_ssh1_kex(void) * cookie. This only affects rhosts authentication, and this is one * of the reasons why it is inherently insecure. */ - for (i = 0; i < 8; i++) { - if (i % 4 == 0) - rnd = arc4random(); - cookie[i] = rnd & 0xff; - rnd >>= 8; - } + arc4random_buf(cookie, sizeof(cookie)); /* * Send our public key. We include in the packet 64 bits of random @@ -2006,10 +2097,10 @@ do_ssh1_kex(void) * key is in the highest bits. */ if (!rsafail) { - BN_mask_bits(session_key_int, sizeof(session_key) * 8); + (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); len = BN_num_bytes(session_key_int); if (len < 0 || (u_int)len > sizeof(session_key)) { - error("do_connection: bad session key len from %s: " + error("do_ssh1_kex: bad session key len from %s: " "session_key_int %d > sizeof(session_key) %lu", get_remote_ipaddr(), len, (u_long)sizeof(session_key)); rsafail++;