X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/e053cd2c3f0b0c9acd5497158bbce91d20eab307..e5ba4718e935294079c084d4f8373f002cc25400:/sshd.c diff --git a/sshd.c b/sshd.c index a8cb966b..332a189e 100644 --- a/sshd.c +++ b/sshd.c @@ -42,7 +42,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.273 2003/07/16 10:34:53 markus Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.291 2004/05/09 01:19:28 djm Exp $"); #include #include @@ -60,7 +60,6 @@ RCSID("$OpenBSD: sshd.c,v 1.273 2003/07/16 10:34:53 markus Exp $"); #include "rsa.h" #include "sshpty.h" #include "packet.h" -#include "mpaux.h" #include "log.h" #include "servconf.h" #include "uidswap.h" @@ -199,11 +198,14 @@ int startup_pipe; /* in child */ /* variables used for privilege separation */ int use_privsep; -struct monitor *pmonitor; +struct monitor *pmonitor = NULL; /* message to be displayed after login */ Buffer loginmsg; +/* global authentication context */ +Authctxt *the_authctxt = NULL; + /* Prototypes for various functions defined later in this file. */ void destroy_sensitive_data(void); void demote_sensitive_data(void); @@ -302,6 +304,9 @@ 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()); } @@ -375,7 +380,7 @@ sshd_exchange_identification(int sock_in, int sock_out) strlen(server_version_string)) != strlen(server_version_string)) { logit("Could not write ident string to %s", get_remote_ipaddr()); - fatal_cleanup(); + cleanup_exit(255); } /* Read other sides version identification. */ @@ -384,7 +389,7 @@ sshd_exchange_identification(int sock_in, int sock_out) if (atomicio(read, sock_in, &buf[i], 1) != 1) { logit("Did not receive identification string from %s", get_remote_ipaddr()); - fatal_cleanup(); + cleanup_exit(255); } if (buf[i] == '\r') { buf[i] = 0; @@ -414,7 +419,7 @@ sshd_exchange_identification(int sock_in, int sock_out) 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); @@ -424,13 +429,13 @@ 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; @@ -476,7 +481,7 @@ sshd_exchange_identification(int sock_in, int 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); } } @@ -561,7 +566,7 @@ 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; @@ -571,10 +576,9 @@ privsep_preauth_child(void) #endif } -static Authctxt * -privsep_preauth(void) +static int +privsep_preauth(Authctxt *authctxt) { - Authctxt *authctxt = NULL; int status; pid_t pid; @@ -587,12 +591,11 @@ 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 */ @@ -602,11 +605,7 @@ 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 */ @@ -617,17 +616,12 @@ 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 @@ -653,8 +647,6 @@ 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); @@ -679,7 +671,8 @@ static char * list_hostkey_types(void) { Buffer b; - char *p; + const char *p; + char *ret; int i; buffer_init(&b); @@ -698,10 +691,10 @@ 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 * @@ -769,25 +762,12 @@ drop_connection(int startups) 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_VERSION, 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); } @@ -809,17 +789,18 @@ 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 startups = 0; - Authctxt *authctxt; Key *key; + Authctxt *authctxt; int ret, key_used = 0; #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 */ @@ -835,6 +816,9 @@ 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); @@ -917,9 +901,11 @@ main(int ac, char **av) } 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: @@ -941,8 +927,15 @@ 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(); @@ -1064,8 +1057,8 @@ 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) @@ -1175,7 +1168,7 @@ main(int ac, char **av) /* Start listening on the port. */ logit("Server listening on %s port %s.", ntop, strport); - if (listen(listen_sock, 5) < 0) + if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) fatal("listen: %.100s", strerror(errno)); } @@ -1368,7 +1361,7 @@ main(int ac, char **av) 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; } @@ -1385,6 +1378,7 @@ 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 @@ -1414,8 +1408,8 @@ main(int ac, char **av) signal(SIGCHLD, SIG_DFL); signal(SIGINT, SIG_DFL); - /* Set keepalives if requested. */ - if (options.keepalives && + /* Set SO_KEEPALIVE if requested. */ + if (options.tcp_keep_alive && setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); @@ -1457,57 +1451,36 @@ main(int ac, char **av) * 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(); - /* prepare buffers to collect authentication messages */ + /* prepare buffers to collect authentication messages */ buffer_init(&loginmsg); + /* allocate authentication context */ + authctxt = xmalloc(sizeof(*authctxt)); + memset(authctxt, 0, sizeof(*authctxt)); + + /* XXX global for cleanup, access from other modules */ + the_authctxt = authctxt; + 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 @@ -1530,7 +1503,7 @@ main(int ac, char **av) destroy_sensitive_data(); } - /* Perform session preparation. */ + /* Start session. */ do_authenticated(authctxt); /* The connection has been terminated. */ @@ -1650,24 +1623,10 @@ 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) @@ -1729,9 +1688,10 @@ do_ssh1_kex(void) BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); - compute_session_id(session_id, cookie, - sensitive_data.ssh1_host_key->rsa->n, - sensitive_data.server_key->rsa->n); + derive_ssh1_session_id( + sensitive_data.ssh1_host_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. @@ -1837,3 +1797,12 @@ do_ssh2_kex(void) #endif debug("KEX done"); } + +/* server specific fatal cleanup */ +void +cleanup_exit(int i) +{ + if (the_authctxt) + do_cleanup(the_authctxt); + _exit(i); +}