X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/e9702f7d1a391091b2fe6510c1e353bd51313b1e..HEAD:/openssh/sshd.c diff --git a/openssh/sshd.c b/openssh/sshd.c index 68a743b..b19bdac 100644 --- a/openssh/sshd.c +++ b/openssh/sshd.c @@ -1,3 +1,4 @@ +/* $OpenBSD: sshd.c,v 1.367 2009/05/28 16:50:16 andreas Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -15,8 +16,10 @@ * called by a name other than "ssh" or "Secure Shell". * * SSH2 implementation: + * Privilege Separation: * - * Copyright (c) 2000 Markus Friedl. All rights reserved. + * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. + * Copyright (c) 2002 Niels Provos. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -40,59 +43,109 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.228 2002/02/27 21:23:13 stevesk Exp $"); + +#include +#include +#include +#ifdef HAVE_SYS_STAT_H +# include +#endif +#ifdef HAVE_SYS_TIME_H +# include +#endif +#include "openbsd-compat/sys-tree.h" +#include "openbsd-compat/sys-queue.h" +#include + +#include +#include +#include +#ifdef HAVE_PATHS_H +#include +#endif +#include +#include +#include +#include +#include +#include +#include +#include #include #include #include +#include +#include "openbsd-compat/openssl-compat.h" +#ifdef HAVE_SECUREWARE +#include +#include +#endif + +#include "xmalloc.h" #include "ssh.h" #include "ssh1.h" #include "ssh2.h" -#include "xmalloc.h" #include "rsa.h" #include "sshpty.h" #include "packet.h" -#include "mpaux.h" #include "log.h" +#include "buffer.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" -#include "buffer.h" #include "cipher.h" -#include "kex.h" #include "key.h" +#include "kex.h" #include "dh.h" #include "myproposal.h" #include "authfile.h" #include "pathnames.h" #include "atomicio.h" #include "canohost.h" +#include "hostfile.h" #include "auth.h" #include "misc.h" +#include "msg.h" #include "dispatch.h" #include "channels.h" - +#include "session.h" +#include "monitor_mm.h" +#include "monitor.h" #ifdef GSSAPI #include "ssh-gss.h" #endif +#include "monitor_wrap.h" +#include "roaming.h" +#include "version.h" +#include "ssh-globus-usage.h" + +#ifdef USE_SECURITY_SESSION_API +#include +#endif #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 #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) + +int myflag = 0; + + extern char *__progname; -#else -char *__progname; -#endif /* Server configuration options. */ ServerOptions options; @@ -100,16 +153,6 @@ 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. - */ -#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 * mode is enabled, extra debugging output will be sent to the system @@ -134,6 +177,12 @@ 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. @@ -184,7 +233,7 @@ 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; @@ -193,8 +242,25 @@ u_int utmp_len = MAXHOSTNAMELEN; int *startup_pipes = NULL; int startup_pipe; /* in child */ +/* variables used for privilege separation */ +int use_privsep = -1; +struct monitor *pmonitor = NULL; + +/* global authentication context */ +Authctxt *the_authctxt = NULL; + +/* sshd_config buffer */ +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); static void do_ssh1_kex(void); static void do_ssh2_kex(void); @@ -206,6 +272,7 @@ static void close_listen_socks(void) { int i; + for (i = 0; i < num_listen_socks; i++) close(listen_socks[i]); num_listen_socks = -1; @@ -215,6 +282,7 @@ static void close_startup_pipes(void) { int i; + if (startup_pipes) for (i = 0; i < options.max_startups; i++) if (startup_pipes[i] != -1) @@ -226,6 +294,8 @@ close_startup_pipes(void) * the effect is to reread the configuration file (and to regenerate * the server key). */ + +/*ARGSUSED*/ static void sighup_handler(int sig) { @@ -243,17 +313,20 @@ sighup_handler(int sig) static void sighup_restart(void) { - log("Received SIGHUP; restarting."); + logit("Received SIGHUP; restarting."); close_listen_socks(); close_startup_pipes(); + alarm(0); /* alarm timer persists across exec */ 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); } /* * Generic signal handler for terminating signals in the master daemon. */ +/*ARGSUSED*/ static void sigterm_handler(int sig) { @@ -264,13 +337,16 @@ sigterm_handler(int sig) * SIGCHLD handler. This is called whenever a child dies. This will then * reap any zombies left by exited children. */ +/*ARGSUSED*/ static void main_sigchld_handler(int sig) { int save_errno = errno; + pid_t pid; int status; - while (waitpid(-1, &status, WNOHANG) > 0) + while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || + (pid < 0 && errno == EINTR)) ; signal(SIGCHLD, main_sigchld_handler); @@ -280,16 +356,15 @@ main_sigchld_handler(int sig) /* * Signal handler for the alarm after the login grace period has expired. */ +/*ARGSUSED*/ static void grace_alarm_handler(int sig) { - /* XXX no idea how fix this signal handler */ - - /* Close the connection. */ - packet_close(); + 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()); + sigdie("Timeout before authentication for %s", get_remote_ipaddr()); } /* @@ -302,9 +377,6 @@ grace_alarm_handler(int sig) static void generate_ephemeral_server_key(void) { - u_int32_t rand = 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) @@ -313,19 +385,16 @@ 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) - rand = arc4random(); - sensitive_data.ssh1_cookie[i] = rand & 0xff; - rand >>= 8; - } + arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); arc4random_stir(); } +/*ARGSUSED*/ static void key_regeneration_alarm(int sig) { int save_errno = errno; + signal(SIGALRM, SIG_DFL); errno = save_errno; key_do_regen = 1; @@ -334,10 +403,11 @@ key_regeneration_alarm(int sig) static void sshd_exchange_identification(int sock_in, int sock_out) { - int i, mismatch; + u_int i; + 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. */ @@ -348,45 +418,46 @@ 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_RELEASE, newline); 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()); - fatal_cleanup(); - } + /* Send our protocol version identification. */ + 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()); + cleanup_exit(255); + } - /* Read other side's 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; + /* Read other sides version identification. */ + memset(buf, 0, sizeof(buf)); + for (i = 0; i < sizeof(buf) - 1; i++) { + if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) { + logit("Did not receive identification string from %s", + get_remote_ipaddr()); + cleanup_exit(255); + } + 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 @@ -395,22 +466,31 @@ 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(); + cleanup_exit(255); } debug("Client protocol version %d.%d; client software version %.100s", remote_major, remote_minor, remote_version); + logit("SSH: Server;Ltype: Version;Remote: %s-%d;Protocol: %d.%d;Client: %.100s", + get_remote_ipaddr(), get_remote_port(), + remote_major, remote_minor, remote_version); compat_datafellows(remote_version); + if (datafellows & SSH_BUG_PROBE) { + logit("probed from %s with %s. Don't panic.", + get_remote_ipaddr(), client_version_string); + cleanup_exit(255); + } + 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(); + cleanup_exit(255); } mismatch = 0; @@ -450,17 +530,16 @@ 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(); + cleanup_exit(255); } } - /* Destroy the host and server keys. They will no longer be needed. */ void destroy_sensitive_data(void) @@ -481,11 +560,172 @@ destroy_sensitive_data(void) memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); } +/* Demote private to public keys for network child */ +void +demote_sensitive_data(void) +{ + Key *tmp; + int i; + + if (sensitive_data.server_key) { + tmp = key_demote(sensitive_data.server_key); + key_free(sensitive_data.server_key); + sensitive_data.server_key = tmp; + } + + for (i = 0; i < options.num_host_key_files; i++) { + if (sensitive_data.host_keys[i]) { + tmp = key_demote(sensitive_data.host_keys[i]); + key_free(sensitive_data.host_keys[i]); + sensitive_data.host_keys[i] = tmp; + if (tmp->type == KEY_RSA1) + sensitive_data.ssh1_host_key = tmp; + } + } + + /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ +} + +static void +privsep_preauth_child(void) +{ + u_int32_t rnd[256]; + gid_t gidset[1]; + + /* Enable challenge-response authentication for privilege separation */ + privsep_challenge_enable(); + + arc4random_stir(); + arc4random_buf(rnd, sizeof(rnd)); + RAND_seed(rnd, sizeof(rnd)); + + /* Demote the private keys to public keys. */ + demote_sensitive_data(); + + /* Change our root directory */ + if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) + fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, + strerror(errno)); + if (chdir("/") == -1) + fatal("chdir(\"/\"): %s", strerror(errno)); + + /* Drop our privileges */ + 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(privsep_pw); +#else + gidset[0] = privsep_pw->pw_gid; + if (setgroups(1, gidset) < 0) + fatal("setgroups: %.100s", strerror(errno)); + permanently_set_uid(privsep_pw); +#endif +} + +static int +privsep_preauth(Authctxt *authctxt) +{ + int status; + pid_t pid; + + /* Set up unprivileged child process to deal with network data */ + pmonitor = monitor_init(); + /* Store a pointer to the kex for later rekeying */ + 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 %ld", (long)pid); + + close(pmonitor->m_recvfd); + pmonitor->m_pid = pid; + monitor_child_preauth(authctxt, pmonitor); + close(pmonitor->m_sendfd); + + /* Sync memory */ + monitor_sync(pmonitor); + + /* Wait for the child's exit status */ + while (waitpid(pid, &status, 0) < 0) + if (errno != EINTR) + break; + return (1); + } else { + /* child */ + + close(pmonitor->m_sendfd); + + /* Demote the child */ + if (getuid() == 0 || geteuid() == 0) + privsep_preauth_child(); + setproctitle("%s", "[net]"); + } + return (0); +} + +static void +privsep_postauth(Authctxt *authctxt) +{ + u_int32_t rnd[256]; + +#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 */ + use_privsep = 0; + goto skip; + } + + /* New socket pair */ + monitor_reinit(pmonitor); + + pmonitor->m_pid = fork(); + if (pmonitor->m_pid == -1) + fatal("fork of unprivileged child failed"); + else if (pmonitor->m_pid != 0) { + verbose("User child is on pid %ld", (long)pmonitor->m_pid); + close(pmonitor->m_recvfd); + buffer_clear(&loginmsg); + monitor_child_postauth(pmonitor); + + /* NEVERREACHED */ + exit(0); + } + + close(pmonitor->m_sendfd); + + /* 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); + + skip: + /* It is safe now to apply the key state */ + monitor_apply_keystate(pmonitor); + + /* + * Tell the packet layer that authentication was successful, since + * this information is not part of the key state. + */ + packet_set_authenticated(); +} + static char * list_hostkey_types(void) { Buffer b; - char *p; + const char *p; + char *ret; int i; buffer_init(&b); @@ -504,16 +744,17 @@ 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; } -static Key * +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) @@ -522,6 +763,26 @@ get_hostkey_by_type(int type) return NULL; } +Key * +get_hostkey_by_index(int ind) +{ + if (ind < 0 || ind >= options.num_host_key_files) + return (NULL); + return (sensitive_data.host_keys[ind]); +} + +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); + } + return (-1); +} + /* * returns 1 if connection should be dropped, 0 otherwise. * dropping starts at connection #max_startups_begin with a probability @@ -531,7 +792,7 @@ get_hostkey_by_type(int type) static int drop_connection(int startups) { - double p, r; + int p, r; if (startups < options.max_startups_begin) return 0; @@ -542,214 +803,732 @@ 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_uniform(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\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_RELEASE, SSLeay_version(SSLEAY_VERSION)); + fprintf(stderr, +"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); } -/* - * Main program for the daemon. - */ -int -main(int ac, char **av) +static void +send_rexec_state(int fd, Buffer *conf) { - extern char *optarg; - extern int optind; - int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1; - pid_t pid; - socklen_t fromlen; - fd_set *fdset; - struct sockaddr_storage from; - 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; - int startup_p[2]; - int startups = 0; - Key *key; - int ret, key_used = 0; + Buffer m; - __progname = get_progname(av[0]); - init_rng(); + debug3("%s: entering fd = %d config len %d", __func__, fd, + buffer_len(conf)); - /* Save argv. */ - saved_argc = ac; - saved_argv = av; + /* + * 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 " + * string rngseed (only if OpenSSL is not self-seeded) + */ + 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); + +#ifndef OPENSSL_PRNG_ONLY + rexec_send_rng_seed(&m); +#endif - /* Initialize configuration options to their default values. */ - initialize_server_options(&options); + if (ssh_msg_send(fd, 0, &m) == -1) + fatal("%s: ssh_msg_send failed", __func__); - /* Parse command-line arguments. */ - while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) { - switch (opt) { - case '4': - IPv4or6 = AF_INET; - break; - case '6': - IPv4or6 = AF_INET6; - break; - case 'f': - config_file_name = optarg; - break; - case 'd': - if (0 == debug_flag) { - debug_flag = 1; - options.log_level = SYSLOG_LEVEL_DEBUG1; - } 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; - break; - case 'e': - log_stderr = 1; - break; - case 'i': - inetd_flag = 1; - break; - case 'Q': - /* ignored */ - break; - case 'q': - options.log_level = SYSLOG_LEVEL_QUIET; - break; - case 'b': - options.server_key_bits = atoi(optarg); - break; - case 'p': - options.ports_from_cmdline = 1; - if (options.num_ports >= MAX_PORTS) { - fprintf(stderr, "too many ports.\n"); - exit(1); - } - options.ports[options.num_ports++] = a2port(optarg); - if (options.ports[options.num_ports-1] == 0) { - fprintf(stderr, "Bad port number.\n"); - exit(1); - } - break; - case 'g': - if ((options.login_grace_time = convtime(optarg)) == -1) { - fprintf(stderr, "Invalid login grace time.\n"); - exit(1); - } - break; - case 'k': - if ((options.key_regeneration_time = convtime(optarg)) == -1) { - fprintf(stderr, "Invalid key regeneration interval.\n"); - exit(1); - } - break; - case 'h': - if (options.num_host_key_files >= MAX_HOSTKEYS) { - fprintf(stderr, "too many host keys.\n"); - exit(1); - } - 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); - break; - case 'o': - if (process_server_config_line(&options, optarg, - "command-line", 0) != 0) - exit(1); - break; - case '?': - default: - usage(); - break; - } - } - SSLeay_add_all_algorithms(); - channel_set_af(IPv4or6); + buffer_free(&m); - /* - * Force logging to stderr until we have loaded the private host - * key (unless started from inetd) - */ - log_init(__progname, - options.log_level == SYSLOG_LEVEL_NOT_SET ? - SYSLOG_LEVEL_INFO : options.log_level, - options.log_facility == SYSLOG_FACILITY_NOT_SET ? - SYSLOG_FACILITY_AUTH : options.log_facility, - !inetd_flag); + debug3("%s: done", __func__); +} -#ifdef _CRAY - /* Cray can define user privs drop all prives now! - * Not needed on PRIV_SU systems! - */ - drop_cray_privs(); +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); + } + +#ifndef OPENSSL_PRNG_ONLY + rexec_recv_rng_seed(&m); #endif - seed_rng(); + buffer_free(&m); - /* Read server configuration options from the configuration file. */ - read_server_config(&options, config_file_name); + debug3("%s: done", __func__); +} + +/* Accept a connection from inetd */ +static void +server_accept_inetd(int *sock_in, int *sock_out) +{ + 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 + * 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); +} + +/* + * Listen for TCP connections + */ +static void +server_listen(void) +{ + int ret, listen_sock, on = 1; + struct addrinfo *ai; + char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + int socksize; + int socksizelen = sizeof(int); + + for (ai = options.listen_addrs; ai; ai = ai->ai_next) { + if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) + continue; + if (num_listen_socks >= MAX_LISTEN_SOCKS) + fatal("Too many listen sockets. " + "Enlarge MAX_LISTEN_SOCKS"); + if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, + ntop, sizeof(ntop), strport, sizeof(strport), + NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { + error("getnameinfo failed: %.100s", + ssh_gai_strerror(ret)); + continue; + } + /* Create socket for listening. */ + 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)); + continue; + } + if (set_nonblock(listen_sock) == -1) { + close(listen_sock); + continue; + } + /* + * Set socket options. + * Allow local port reuse in TIME_WAIT. + */ + if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, + &on, sizeof(on)) == -1) + error("setsockopt SO_REUSEADDR: %s", strerror(errno)); + +#ifdef IPV6_V6ONLY + /* Only communicate in IPv6 over AF_INET6 sockets. */ + if (ai->ai_family == AF_INET6) { + if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY, + &on, sizeof(on)) == -1) + error("setsockopt IPV6_V6ONLY: %s", + strerror(errno)); + } +#endif + + debug("Bind to port %s on %s.", strport, ntop); + + getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, + &socksize, &socksizelen); + debug("Server TCP RWIN socket size: %d", socksize); + debug("HPN Buffer Size: %d", options.hpn_buffer_size); + + /* Bind the socket to the desired port. */ + if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { + error("Bind to port %s on %s failed: %.200s.", + strport, ntop, strerror(errno)); + close(listen_sock); + continue; + } + listen_socks[num_listen_socks] = listen_sock; + num_listen_socks++; + + /* Start listening on the port. */ + if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) + fatal("listen on [%s]:%s: %.100s", + ntop, strport, strerror(errno)); + logit("Server listening on %s port %s.", ntop, strport); + } + freeaddrinfo(options.listen_addrs); + + if (!num_listen_socks) + fatal("Cannot bind any address."); +} + +/* + * The main TCP accept loop. Note that, for the non-debug case, returns + * from this function are in a forked subprocess. + */ +static void +server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) +{ + fd_set *fdset; + int i, j, ret, maxfd; + int key_used = 0, startups = 0; + int startup_p[2] = { -1 , -1 }; + struct sockaddr_storage from; + socklen_t fromlen; + pid_t pid; + + /* setup fd set for accept */ + fdset = NULL; + maxfd = 0; + for (i = 0; i < num_listen_socks; i++) + if (listen_socks[i] > maxfd) + maxfd = listen_socks[i]; + /* pipes connected to unauthenticated childs */ + startup_pipes = xcalloc(options.max_startups, sizeof(int)); + for (i = 0; i < options.max_startups; i++) + startup_pipes[i] = -1; + + /* + * Stay listening for connections until the system crashes or + * the daemon is killed with a signal. + */ + for (;;) { + if (received_sighup) + sighup_restart(); + if (fdset != NULL) + xfree(fdset); + fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), + sizeof(fd_mask)); + + for (i = 0; i < num_listen_socks; i++) + FD_SET(listen_socks[i], fdset); + for (i = 0; i < options.max_startups; i++) + if (startup_pipes[i] != -1) + FD_SET(startup_pipes[i], fdset); + + /* Wait in select until there is a connection. */ + ret = select(maxfd+1, fdset, NULL, NULL, NULL); + if (ret < 0 && errno != EINTR) + error("select: %.100s", strerror(errno)); + if (received_sigterm) { + logit("Received signal %d; terminating.", + (int) received_sigterm); + close_listen_socks(); + unlink(options.pid_file); + exit(255); + } + if (key_used && key_do_regen) { + generate_ephemeral_server_key(); + key_used = 0; + key_do_regen = 0; + } + if (ret < 0) + continue; + + for (i = 0; i < options.max_startups; i++) + if (startup_pipes[i] != -1 && + FD_ISSET(startup_pipes[i], fdset)) { + /* + * the read end of the pipe is ready + * if the child has closed the pipe + * after successful authentication + * or if the child has died + */ + close(startup_pipes[i]); + startup_pipes[i] = -1; + startups--; + } + for (i = 0; i < num_listen_socks; i++) { + if (!FD_ISSET(listen_socks[i], fdset)) + continue; + fromlen = sizeof(from); + *newsock = accept(listen_socks[i], + (struct sockaddr *)&from, &fromlen); + if (*newsock < 0) { + if (errno != EINTR && errno != EAGAIN && + errno != EWOULDBLOCK) + error("accept: %.100s", strerror(errno)); + continue; + } + if (unset_nonblock(*newsock) == -1) { + close(*newsock); + continue; + } + if (drop_connection(startups) == 1) { + debug("drop connection #%d", startups); + close(*newsock); + continue; + } + if (pipe(startup_p) == -1) { + close(*newsock); + 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]; + if (maxfd < startup_p[0]) + maxfd = startup_p[0]; + startups++; + break; + } + + /* + * Got connection. Fork a child to handle it, unless + * we are in debugging mode. + */ + if (debug_flag) { + /* + * In debugging mode. Close the listening + * socket, and start processing the + * connection without forking. + */ + debug("Server will not fork when running in debugging mode."); + 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; + } + + /* + * Normal production daemon. Fork, and have + * the child process the connection. The + * parent continues listening. + */ + platform_pre_fork(); + if ((pid = fork()) == 0) { + /* + * Child. Close the listening and + * max_startup sockets. Start using + * the accepted socket. Reinitialize + * logging (since our pid has changed). + * We break out of the loop to handle + * the connection. + */ + platform_post_fork_child(); + startup_pipe = startup_p[1]; + close_startup_pipes(); + close_listen_socks(); + *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; + } + + /* Parent. Stay in the loop. */ + platform_post_fork_parent(pid); + if (pid < 0) + error("fork: %.100s", strerror(errno)); + else + debug("Forked child %ld.", (long)pid); + + 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) { + /* Schedule server key regeneration alarm. */ + signal(SIGALRM, key_regeneration_alarm); + alarm(options.key_regeneration_time); + key_used = 1; + } + + close(*newsock); + + /* + * Ensure that our random state differs + * from that of the child + */ + arc4random_stir(); + } + + /* child process check (or debug mode) */ + if (num_listen_socks < 0) + break; + } +} + + +/* + * Main program for the daemon. + */ +int +main(int ac, char **av) +{ + extern char *optarg; + extern int optind; + 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, *p, *cp; + int config_s[2] = { -1 , -1 }; + u_int64_t ibytes, obytes; + mode_t new_umask; + Key *key; + Authctxt *authctxt; + +#ifdef HAVE_SECUREWARE + (void)set_auth_parameters(ac, av); +#endif + __progname = ssh_get_progname(av[0]); + init_rng(); + + /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ + saved_argc = ac; + rexec_argc = ac; + saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); + 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 + + if (geteuid() == 0 && setgroups(0, NULL) == -1) + debug("setgroups(): %.200s", strerror(errno)); + + /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ + sanitise_stdfd(); + + /* 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:C:dDeiqrtQRT46")) != -1) { + switch (opt) { + case '4': + options.address_family = AF_INET; + break; + case '6': + options.address_family = AF_INET6; + break; + case 'f': + config_file_name = optarg; + break; + case 'd': + if (debug_flag == 0) { + debug_flag = 1; + options.log_level = SYSLOG_LEVEL_DEBUG1; + } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) + options.log_level++; + break; + case 'D': + no_daemon_flag = 1; + break; + case 'e': + log_stderr = 1; + break; + 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; + case 'q': + options.log_level = SYSLOG_LEVEL_QUIET; + break; + case 'b': + options.server_key_bits = (int)strtonum(optarg, 256, + 32768, NULL); + break; + case 'p': + options.ports_from_cmdline = 1; + if (options.num_ports >= MAX_PORTS) { + fprintf(stderr, "too many ports.\n"); + exit(1); + } + options.ports[options.num_ports++] = a2port(optarg); + if (options.ports[options.num_ports-1] <= 0) { + fprintf(stderr, "Bad port number.\n"); + exit(1); + } + break; + case 'g': + if ((options.login_grace_time = convtime(optarg)) == -1) { + fprintf(stderr, "Invalid login grace time.\n"); + exit(1); + } + break; + case 'k': + if ((options.key_regeneration_time = convtime(optarg)) == -1) { + fprintf(stderr, "Invalid key regeneration interval.\n"); + exit(1); + } + break; + case 'h': + if (options.num_host_key_files >= MAX_HOSTKEYS) { + fprintf(stderr, "too many host keys.\n"); + exit(1); + } + options.host_key_files[options.num_host_key_files++] = 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) { + fprintf(stderr, "Invalid utmp length.\n"); + exit(1); + } + break; + case 'o': + line = xstrdup(optarg); + if (process_server_config_line(&options, line, + "command-line", 0, NULL, NULL, NULL, NULL) != 0) + exit(1); + xfree(line); + break; + case '?': + default: + usage(); + break; + } + } + if (rexeced_flag || inetd_flag) + rexec_flag = 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); + else + closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); + + SSLeay_add_all_algorithms(); + + /* + * Force logging to stderr until we have loaded the private host + * key (unless started from inetd) + */ + log_init(__progname, + options.log_level == SYSLOG_LEVEL_NOT_SET ? + SYSLOG_LEVEL_INFO : options.log_level, + options.log_facility == SYSLOG_FACILITY_NOT_SET ? + SYSLOG_FACILITY_AUTH : options.log_facility, + log_stderr || !inetd_flag); + + /* + * Unset KRB5CCNAME, otherwise the user's session may inherit it from + * root's environment + */ + if (getenv("KRB5CCNAME") != NULL) + unsetenv("KRB5CCNAME"); + +#ifdef _UNICOS + /* Cray can define user privs drop all privs now! + * Not needed on PRIV_SU systems! + */ + drop_cray_privs(); +#endif + + sensitive_data.server_key = NULL; + sensitive_data.ssh1_host_key = NULL; + 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) + 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, NULL, NULL, NULL); + + seed_rng(); /* Fill in default values for those options not explicitly set. */ fill_default_server_options(&options); +#ifdef HAVE_GLOBUS_USAGE + if (ssh_usage_stats_init(options.disable_usage_stats, + options.usage_stats_targets) != GLOBUS_SUCCESS) { + fatal("Error initializing Globus Usage Metrics"); + } +#endif /* HAVE_GLOBUS_USAGE */ + + /* 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); + /* 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); + + /* 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 = xmalloc(options.num_host_key_files*sizeof(Key*)); + sensitive_data.host_keys = xcalloc(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); @@ -774,18 +1553,18 @@ 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; } #ifndef GSSAPI /* The GSSAPI key exchange can run without a host key */ 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; } #endif if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { - log("sshd: no hostkeys available -- exiting."); + logit("sshd: no hostkeys available -- exiting."); exit(1); } @@ -802,26 +1581,74 @@ 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 stat st; + + 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); + } + + 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); -#ifdef HAVE_SCO_PROTECTED_PW - (void) set_auth_parameters(ac, av); -#endif + /* + * 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 + * module which might be used). + */ + if (setgroups(0, NULL) < 0) + debug("setgroups() failed: %.200s", strerror(errno)); + + if (rexec_flag) { + rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); + 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; + } + + /* 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) + if (debug_flag && (!inetd_flag || rexeced_flag)) log_stderr = 1; log_init(__progname, options.log_level, options.log_facility, log_stderr); @@ -859,283 +1686,99 @@ main(int ac, char **av) /* ignore SIGPIPE */ signal(SIGPIPE, SIG_IGN); - /* Start listening for a socket, unless started from inetd. */ + /* Get a connection, either from inetd or a listening TCP socket */ 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); - startup_pipe = -1; - /* - * We intentionally do not close the descriptors 0, 1, and 2 - * as our code for setting the descriptors won\'t work if - * ttyfd happens to be one of those. - */ - debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); - if (options.protocol & SSH_PROTO_1) - generate_ephemeral_server_key(); + server_accept_inetd(&sock_in, &sock_out); } else { - for (ai = options.listen_addrs; ai; ai = ai->ai_next) { - if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) - continue; - if (num_listen_socks >= MAX_LISTEN_SOCKS) - fatal("Too many listen sockets. " - "Enlarge MAX_LISTEN_SOCKS"); - if (getnameinfo(ai->ai_addr, ai->ai_addrlen, - ntop, sizeof(ntop), strport, sizeof(strport), - NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("getnameinfo failed"); - continue; - } - /* Create socket for listening. */ - listen_sock = socket(ai->ai_family, SOCK_STREAM, 0); - if (listen_sock < 0) { - /* kernel may not support ipv6 */ - verbose("socket: %.100s", strerror(errno)); - continue; - } - if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) { - error("listen_sock O_NONBLOCK: %s", strerror(errno)); - close(listen_sock); - 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. - */ - 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)); - - debug("Bind to port %s on %s.", strport, ntop); - - /* Bind the socket to the desired port. */ - if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { - if (!ai->ai_next) - error("Bind to port %s on %s failed: %.200s.", - strport, ntop, strerror(errno)); - close(listen_sock); - continue; - } - listen_socks[num_listen_socks] = listen_sock; - num_listen_socks++; - - /* Start listening on the port. */ - log("Server listening on %s port %s.", ntop, strport); - if (listen(listen_sock, 5) < 0) - fatal("listen: %.100s", strerror(errno)); - - } - freeaddrinfo(options.listen_addrs); - - if (!num_listen_socks) - fatal("Cannot bind any address."); + server_listen(); if (options.protocol & SSH_PROTO_1) generate_ephemeral_server_key(); - /* - * Arrange to restart on SIGHUP. The handler needs - * listen_sock. - */ signal(SIGHUP, sighup_handler); - + signal(SIGCHLD, main_sigchld_handler); signal(SIGTERM, sigterm_handler); signal(SIGQUIT, sigterm_handler); - /* Arrange SIGCHLD to be caught. */ - signal(SIGCHLD, main_sigchld_handler); - - /* Write out the pid file after the sigterm handler is setup */ + /* + * Write out the pid file after the sigterm handler + * is setup and the listen sockets are bound + */ if (!debug_flag) { - /* - * Record our pid in /var/run/sshd.pid to make it - * easier to kill the correct sshd. We don't want to - * do this before the bind above because the bind will - * fail if there already is a daemon, and this will - * overwrite any old pid in the file. - */ - f = fopen(options.pid_file, "wb"); - if (f) { - fprintf(f, "%u\n", (u_int) getpid()); + FILE *f = fopen(options.pid_file, "w"); + + 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); } } - /* setup fd set for listen */ - fdset = NULL; - maxfd = 0; - for (i = 0; i < num_listen_socks; i++) - if (listen_socks[i] > maxfd) - maxfd = listen_socks[i]; - /* pipes connected to unauthenticated childs */ - startup_pipes = xmalloc(options.max_startups * sizeof(int)); - for (i = 0; i < options.max_startups; i++) - startup_pipes[i] = -1; - - /* - * Stay listening for connections until the system crashes or - * the daemon is killed with a signal. - */ - for (;;) { - if (received_sighup) - sighup_restart(); - if (fdset != NULL) - xfree(fdset); - fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); - fdset = (fd_set *)xmalloc(fdsetsz); - memset(fdset, 0, fdsetsz); - - for (i = 0; i < num_listen_socks; i++) - FD_SET(listen_socks[i], fdset); - for (i = 0; i < options.max_startups; i++) - if (startup_pipes[i] != -1) - FD_SET(startup_pipes[i], fdset); - - /* Wait in select until there is a connection. */ - ret = select(maxfd+1, fdset, NULL, NULL, NULL); - if (ret < 0 && errno != EINTR) - error("select: %.100s", strerror(errno)); - if (received_sigterm) { - log("Received signal %d; terminating.", - (int) received_sigterm); - close_listen_socks(); - unlink(options.pid_file); - exit(255); - } - if (key_used && key_do_regen) { - generate_ephemeral_server_key(); - key_used = 0; - key_do_regen = 0; - } - if (ret < 0) - continue; - - for (i = 0; i < options.max_startups; i++) - if (startup_pipes[i] != -1 && - FD_ISSET(startup_pipes[i], fdset)) { - /* - * the read end of the pipe is ready - * if the child has closed the pipe - * after successful authentication - * or if the child has died - */ - close(startup_pipes[i]); - startup_pipes[i] = -1; - startups--; - } - for (i = 0; i < num_listen_socks; i++) { - if (!FD_ISSET(listen_socks[i], fdset)) - continue; - fromlen = sizeof(from); - newsock = accept(listen_socks[i], (struct sockaddr *)&from, - &fromlen); - if (newsock < 0) { - if (errno != EINTR && errno != EWOULDBLOCK) - error("accept: %.100s", strerror(errno)); - continue; - } - if (fcntl(newsock, F_SETFL, 0) < 0) { - error("newsock del O_NONBLOCK: %s", strerror(errno)); - close(newsock); - continue; - } - if (drop_connection(startups) == 1) { - debug("drop connection #%d", startups); - close(newsock); - continue; - } - if (pipe(startup_p) == -1) { - close(newsock); - continue; - } - - for (j = 0; j < options.max_startups; j++) - if (startup_pipes[j] == -1) { - startup_pipes[j] = startup_p[0]; - if (maxfd < startup_p[0]) - maxfd = startup_p[0]; - startups++; - break; - } - - /* - * Got connection. Fork a child to handle it, unless - * we are in debugging mode. - */ - if (debug_flag) { - /* - * In debugging mode. Close the listening - * socket, and start processing the - * connection without forking. - */ - debug("Server will not fork when running in debugging mode."); - close_listen_socks(); - sock_in = newsock; - sock_out = newsock; - startup_pipe = -1; - pid = getpid(); - break; - } else { - /* - * Normal production daemon. Fork, and have - * the child process the connection. The - * parent continues listening. - */ - if ((pid = fork()) == 0) { - /* - * Child. Close the listening and max_startup - * sockets. Start using the accepted socket. - * Reinitialize logging (since our pid has - * changed). We break out of the loop to handle - * the connection. - */ - startup_pipe = startup_p[1]; - close_startup_pipes(); - close_listen_socks(); - sock_in = newsock; - sock_out = newsock; - log_init(__progname, options.log_level, options.log_facility, log_stderr); - break; - } - } - - /* Parent. Stay in the loop. */ - if (pid < 0) - error("fork: %.100s", strerror(errno)); - else - debug("Forked child %d.", pid); + /* Accept a connection and return in a forked child */ + server_accept_loop(&sock_in, &sock_out, + &newsock, config_s); + } - close(startup_p[1]); + /* This is the child processing a new connection. */ + setproctitle("%s", "[accepted]"); - /* Mark that the key has been used (it was "given" to the child). */ - if ((options.protocol & SSH_PROTO_1) && - key_used == 0) { - /* Schedule server key regeneration alarm. */ - signal(SIGALRM, key_regeneration_alarm); - alarm(options.key_regeneration_time); - key_used = 1; - } + /* + * Create a new session and process group since the 4.4BSD + * setlogin() affects the entire process group. We don't + * want the child to be able to affect the parent. + */ +#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 - arc4random_stir(); + if (rexec_flag) { + int fd; - /* Close the new socket (the child is now taking care of it). */ - close(newsock); - } - /* child process check (or debug mode) */ - if (num_listen_socks < 0) - break; + 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]); } - /* This is the child processing a new connection. */ - /* * 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 @@ -1149,34 +1792,46 @@ 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, - sizeof(on)) < 0) - error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); - /* * Register our connection. This turns encryption off because we do * not have a key. */ packet_set_connection(sock_in, sock_out); + packet_set_server(); + + /* Set SO_KEEPALIVE if requested. */ + if (options.tcp_keep_alive && packet_connection_is_on_socket() && + setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) + error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); + + if ((remote_port = get_remote_port()) < 0) { + debug("get_remote_port failed"); + cleanup_exit(255); + } + + /* set the HPN options for the child */ + channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size); - remote_port = get_remote_port(); + /* + * We use get_canonical_hostname with usedns = 0 instead of + * get_remote_ipaddr here so IP options will be checked. + */ + (void) get_canonical_hostname(0); + /* + * The rest of the code depends on the fact that + * get_remote_ipaddr() caches the remote ip, even if + * the socket goes away. + */ remote_ip = get_remote_ipaddr(); +#ifdef SSH_AUDIT_EVENTS + 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; request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); @@ -1194,11 +1849,65 @@ main(int ac, char **av) /* Log the connection. */ verbose("Connection from %.500s port %d", remote_ip, remote_port); +#ifdef USE_SECURITY_SESSION_API + /* + * Create a new security session for use by the new user login if + * the current session is the root session or we are not launched + * by inetd (eg: debugging mode or server mode). We do not + * necessarily need to create a session if we are launched from + * inetd because Panther xinetd will create a session for us. + * + * The only case where this logic will fail is if there is an + * inetd running in a non-root session which is not creating + * new sessions for us. Then all the users will end up in the + * same session (bad). + * + * When the client exits, the session will be destroyed for us + * automatically. + * + * We must create the session before any credentials are stored + * (including AFS pags, which happens a few lines below). + */ + { + OSStatus err = 0; + SecuritySessionId sid = 0; + SessionAttributeBits sattrs = 0; + + err = SessionGetInfo(callerSecuritySession, &sid, &sattrs); + if (err) + error("SessionGetInfo() failed with error %.8X", + (unsigned) err); + else + debug("Current Session ID is %.8X / Session Attributes are %.8X", + (unsigned) sid, (unsigned) sattrs); + + if (inetd_flag && !(sattrs & sessionIsRoot)) + debug("Running in inetd mode in a non-root session... " + "assuming inetd created the session for us."); + else { + debug("Creating new security session..."); + err = SessionCreate(0, sessionHasTTY | sessionIsRemote); + if (err) + error("SessionCreate() failed with error %.8X", + (unsigned) err); + + err = SessionGetInfo(callerSecuritySession, &sid, + &sattrs); + if (err) + error("SessionGetInfo() failed with error %.8X", + (unsigned) err); + else + debug("New Session ID is %.8X / Session Attributes are %.8X", + (unsigned) sid, (unsigned) sattrs); + } + } +#endif + /* - * We don\'t want to listen forever unless the other side + * We don't want to listen forever unless the other side * successfully authenticates itself. So we set up an alarm which is * cleared after successful authentication. A limit of zero - * indicates no limit. Note that we don\'t set the alarm in debugging + * indicates no limit. Note that we don't set the alarm in debugging * mode; it is just annoying to have the server exit just when you * are about to discover the bug. */ @@ -1207,57 +1916,174 @@ 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 priviledged - * 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 defined(AFS_KRB5) /* If machine has AFS, set process authentication group. */ if (k_hasafs()) { k_setpag(); k_unlog(); } -#endif /* AFS */ +#endif /* AFS || AFS_KRB5 */ + + /* 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 */ + authctxt = xcalloc(1, sizeof(*authctxt)); + + authctxt->loginmsg = &loginmsg; + + /* XXX global for cleanup, access from other modules */ + the_authctxt = authctxt; + + /* prepare buffer to collect messages to display to user after login */ + buffer_init(&loginmsg); + + if (use_privsep) + if (privsep_preauth(authctxt) == 1) + goto authenticated; + /* perform the key exchange */ /* authenticate user and start session */ if (compat20) { do_ssh2_kex(); - do_authentication2(); + do_authentication2(authctxt); } else { do_ssh1_kex(); - do_authentication(); + do_authentication(authctxt); + } + /* + * If we use privilege separation, the unprivileged child transfers + * the current keystate and exits + */ + if (use_privsep) { + mm_send_keystate(pmonitor); + exit(0); + } + + authenticated: + /* + * Cancel the alarm we set to limit the time taken for + * authentication. + */ + alarm(0); + signal(SIGALRM, SIG_DFL); + authctxt->authenticated = 1; + if (startup_pipe != -1) { + close(startup_pipe); + startup_pipe = -1; + } + +#ifdef SSH_AUDIT_EVENTS + audit_event(SSH_AUTH_SUCCESS); +#endif + +#ifdef GSSAPI + if (options.gss_authentication && options.gss_deleg_creds) { + 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. + */ + if (use_privsep) { + privsep_postauth(authctxt); + /* the monitor process [priv] will not return */ + if (!compat20) + 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 - finish_pam(); + if (options.use_pam) + finish_pam(); #endif /* USE_PAM */ +#ifdef SSH_AUDIT_EVENTS + PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); +#endif + packet_close(); + + if (use_privsep) + mm_terminate(); + exit(0); } +/* + * Decrypt session_key_int using our private server key and private host key + * (key with larger modulus first). + */ +int +ssh1_session_key(BIGNUM *session_key_int) +{ + int rsafail = 0; + + if (BN_cmp(sensitive_data.server_key->rsa->n, + sensitive_data.ssh1_host_key->rsa->n) > 0) { + /* Server key has bigger modulus. */ + if (BN_num_bits(sensitive_data.server_key->rsa->n) < + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + + SSH_KEY_BITS_RESERVED) { + fatal("do_connection: %s: " + "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", + get_remote_ipaddr(), + BN_num_bits(sensitive_data.server_key->rsa->n), + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), + SSH_KEY_BITS_RESERVED); + } + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.server_key->rsa) <= 0) + rsafail++; + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.ssh1_host_key->rsa) <= 0) + rsafail++; + } else { + /* Host key has bigger modulus (or they are equal). */ + if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < + BN_num_bits(sensitive_data.server_key->rsa->n) + + SSH_KEY_BITS_RESERVED) { + fatal("do_connection: %s: " + "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", + get_remote_ipaddr(), + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), + BN_num_bits(sensitive_data.server_key->rsa->n), + SSH_KEY_BITS_RESERVED); + } + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.ssh1_host_key->rsa) < 0) + rsafail++; + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.server_key->rsa) < 0) + rsafail++; + } + return (rsafail); +} /* * SSH1 key exchange */ @@ -1270,7 +2096,6 @@ 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 rand = 0; /* * Generate check bytes that the client must send back in the user @@ -1281,12 +2106,7 @@ 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) - rand = arc4random(); - cookie[i] = rand & 0xff; - rand >>= 8; - } + arc4random_buf(cookie, sizeof(cookie)); /* * Send our public key. We include in the packet 64 bits of random @@ -1315,24 +2135,10 @@ 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) @@ -1373,55 +2179,19 @@ do_ssh1_kex(void) packet_set_protocol_flags(protocol_flags); packet_check_eom(); - packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY); + /* Decrypt session_key_int using host/server keys */ + rsafail = PRIVSEP(ssh1_session_key(session_key_int)); - /* - * Decrypt it using our private server key and private host key (key - * with larger modulus first). - */ - if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { - /* Server key has bigger modulus. */ - if (BN_num_bits(sensitive_data.server_key->rsa->n) < - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { - fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", - get_remote_ipaddr(), - BN_num_bits(sensitive_data.server_key->rsa->n), - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), - SSH_KEY_BITS_RESERVED); - } - if (rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.server_key->rsa) <= 0) - rsafail++; - if (rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.ssh1_host_key->rsa) <= 0) - rsafail++; - } else { - /* Host key has bigger modulus (or they are equal). */ - if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < - BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { - fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", - get_remote_ipaddr(), - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), - BN_num_bits(sensitive_data.server_key->rsa->n), - SSH_KEY_BITS_RESERVED); - } - if (rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.ssh1_host_key->rsa) < 0) - rsafail++; - if (rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.server_key->rsa) < 0) - rsafail++; - } /* * Extract session key from the decrypted integer. The key is in the * least significant 256 bits of the integer; the first byte of the * 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 || len > sizeof(session_key)) { - error("do_connection: bad session key len from %s: " + if (len < 0 || (u_int)len > sizeof(session_key)) { + 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++; @@ -1430,9 +2200,10 @@ 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. @@ -1446,7 +2217,7 @@ 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); @@ -1462,9 +2233,12 @@ do_ssh1_kex(void) for (i = 0; i < 16; i++) session_id[i] = session_key[i] ^ session_key[i + 16]; } - /* Destroy the private and public keys. They will no longer be needed. */ + /* Destroy the private and public keys. No longer. */ destroy_sensitive_data(); + if (use_privsep) + mm_ssh1_session_id(session_id); + /* Destroy the decrypted integer. It is no longer needed. */ BN_clear_free(session_key_int); @@ -1476,7 +2250,7 @@ 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(); @@ -1490,9 +2264,15 @@ do_ssh2_kex(void) { Kex *kex; + myflag++; + debug ("MYFLAG IS %d", myflag); if (options.ciphers != NULL) { myproposal[PROPOSAL_ENC_ALGS_CTOS] = myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; + } else if (options.none_enabled == 1) { + debug ("WARNING: None cipher enabled"); + myproposal[PROPOSAL_ENC_ALGS_CTOS] = + myproposal[PROPOSAL_ENC_ALGS_STOC] = KEX_ENCRYPT_INCLUDE_NONE; } myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); @@ -1503,53 +2283,76 @@ do_ssh2_kex(void) myproposal[PROPOSAL_MAC_ALGS_CTOS] = myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; } + if (options.compression == COMP_NONE) { + myproposal[PROPOSAL_COMP_ALGS_CTOS] = + myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; + } else if (options.compression == COMP_DELAYED) { + myproposal[PROPOSAL_COMP_ALGS_CTOS] = + myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; + } + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); #ifdef GSSAPI - { + { char *orig; char *gss = NULL; char *newstr = NULL; - orig = myproposal[PROPOSAL_KEX_ALGS]; - - /* If we don't have a host key, then all of the algorithms - * currently in myproposal are useless */ - if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])==0) - orig= NULL; - - if (options.gss_keyex) - gss = ssh_gssapi_mechanisms(1,NULL); - else - gss = NULL; - - if (gss && orig) { - int len = strlen(orig) + strlen(gss) +2; - newstr=xmalloc(len); - snprintf(newstr,len,"%s,%s",gss,orig); - } else if (gss) { - newstr=gss; - } else if (orig) { - newstr=orig; - } - /* If we've got GSSAPI mechanisms, then we've also got the 'null' - host key algorithm, but we're not allowed to advertise it, unless - its the only host key algorithm we're supporting */ - if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) { - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]="null"; - } + orig = myproposal[PROPOSAL_KEX_ALGS]; + + /* + * If we don't have a host key, then there's no point advertising + * the other key exchange algorithms + */ + + if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0) + orig = NULL; + + if (options.gss_keyex) + gss = ssh_gssapi_server_mechanisms(); + else + gss = NULL; + + if (gss && orig) + xasprintf(&newstr, "%s,%s", gss, orig); + else if (gss) + newstr = gss; + else if (orig) + newstr = orig; + + /* + * If we've got GSSAPI mechanisms, then we've got the 'null' host + * key alg, but we can't tell people about it unless its the only + * host key algorithm we support + */ + if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null"; + if (newstr) - myproposal[PROPOSAL_KEX_ALGS]=newstr; + myproposal[PROPOSAL_KEX_ALGS] = newstr; else fatal("No supported key exchange algorithms"); - } + } #endif /* 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->kex[KEX_DH_GEX_SHA256] = kexgex_server; +#ifdef GSSAPI + if (options.gss_keyex) { + kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; + kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server; + kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; + } +#endif kex->server = 1; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->load_host_key=&get_hostkey_by_type; + kex->host_key_index=&get_hostkey_index; xxx_kex = kex; @@ -1567,3 +2370,17 @@ do_ssh2_kex(void) #endif debug("KEX done"); } + +/* server specific fatal cleanup */ +void +cleanup_exit(int i) +{ + if (the_authctxt) + do_cleanup(the_authctxt); +#ifdef SSH_AUDIT_EVENTS + /* done after do_cleanup so it can cancel the PAM auth 'thread' */ + if (!use_privsep || mm_is_monitor()) + audit_event(SSH_CONNECTION_ABANDON); +#endif + _exit(i); +}