X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/3c0ef6268ff5921062694dbd2cbb80f558aa8d40..a7045e2e7435a176522df49a644f13d47b5291af:/openssh/sshd.c diff --git a/openssh/sshd.c b/openssh/sshd.c index 71a5c2c..92aa9bb 100644 --- a/openssh/sshd.c +++ b/openssh/sshd.c @@ -15,8 +15,10 @@ * 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 @@ -40,11 +42,16 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.209 2001/11/10 13:19:45 markus Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.312 2005/07/25 11:59:40 markus Exp $"); #include #include -#include +#include +#include +#ifdef HAVE_SECUREWARE +#include +#include +#endif #include "ssh.h" #include "ssh1.h" @@ -53,12 +60,12 @@ RCSID("$OpenBSD: sshd.c,v 1.209 2001/11/10 13:19:45 markus Exp $"); #include "rsa.h" #include "sshpty.h" #include "packet.h" -#include "mpaux.h" #include "log.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" #include "buffer.h" +#include "bufaux.h" #include "cipher.h" #include "kex.h" #include "key.h" @@ -70,8 +77,14 @@ RCSID("$OpenBSD: sshd.c,v 1.209 2001/11/10 13:19:45 markus Exp $"); #include "canohost.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" +#include "monitor_wrap.h" +#include "monitor_fdpass.h" #ifdef LIBWRAP #include @@ -84,11 +97,13 @@ int deny_severity = LOG_WARNING; #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) + extern char *__progname; -#else -char *__progname; -#endif /* Server configuration options. */ ServerOptions options; @@ -96,16 +111,6 @@ 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 @@ -130,6 +135,12 @@ 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. @@ -169,24 +180,39 @@ struct { * Flag indicating whether the RSA server key needs to be regenerated. * Is set in the SIGALRM handler and cleared when the key is regenerated. */ -int key_do_regen = 0; +static volatile sig_atomic_t key_do_regen = 0; /* This is set to true when a signal is received. */ -int received_sighup = 0; -int received_sigterm = 0; +static volatile sig_atomic_t received_sighup = 0; +static volatile sig_atomic_t received_sigterm = 0; /* session identifier, used by RSA-auth */ 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; +/* options.max_startup sized array of fd ints */ +int *startup_pipes = NULL; +int startup_pipe; /* in child */ + +/* variables used for privilege separation */ +int use_privsep; +struct monitor *pmonitor = NULL; + +/* global authentication context */ +Authctxt *the_authctxt = NULL; + +/* message to be displayed after login */ +Buffer loginmsg; + /* 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); @@ -198,11 +224,23 @@ static void close_listen_socks(void) { int i; + for (i = 0; i < num_listen_socks; i++) close(listen_socks[i]); num_listen_socks = -1; } +static void +close_startup_pipes(void) +{ + int i; + + if (startup_pipes) + for (i = 0; i < options.max_startups; i++) + if (startup_pipes[i] != -1) + close(startup_pipes[i]); +} + /* * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; * the effect is to reread the configuration file (and to regenerate @@ -211,8 +249,11 @@ close_listen_socks(void) static void sighup_handler(int sig) { + int save_errno = errno; + received_sighup = 1; signal(SIGHUP, sighup_handler); + errno = save_errno; } /* @@ -222,10 +263,12 @@ sighup_handler(int sig) static void sighup_restart(void) { - log("Received SIGHUP; restarting."); + logit("Received SIGHUP; restarting."); close_listen_socks(); + close_startup_pipes(); execv(saved_argv[0], saved_argv); - log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); + logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], + strerror(errno)); exit(1); } @@ -246,9 +289,11 @@ 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); @@ -263,11 +308,11 @@ 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()); + fatal("Timeout before authentication for %s", get_remote_ipaddr()); } /* @@ -280,7 +325,7 @@ grace_alarm_handler(int sig) static void generate_ephemeral_server_key(void) { - u_int32_t rand = 0; + u_int32_t rnd = 0; int i; verbose("Generating %s%d bit RSA key.", @@ -293,9 +338,9 @@ generate_ephemeral_server_key(void) for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { if (i % 4 == 0) - rand = arc4random(); - sensitive_data.ssh1_cookie[i] = rand & 0xff; - rand >>= 8; + rnd = arc4random(); + sensitive_data.ssh1_cookie[i] = rnd & 0xff; + rnd >>= 8; } arc4random_stir(); } @@ -304,6 +349,7 @@ static void key_regeneration_alarm(int sig) { int save_errno = errno; + signal(SIGALRM, SIG_DFL); errno = save_errno; key_do_regen = 1; @@ -312,7 +358,8 @@ 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; @@ -333,38 +380,37 @@ sshd_exchange_identification(int sock_in, int sock_out) snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); server_version_string = xstrdup(buf); - if (client_version_string == NULL) { - /* Send our protocol version identification. */ - if (atomicio(write, sock_out, server_version_string, strlen(server_version_string)) - != strlen(server_version_string)) { - log("Could not write ident string to %s", get_remote_ipaddr()); - fatal_cleanup(); - } + /* Send our protocol version identification. */ + if (atomicio(vwrite, sock_out, server_version_string, + strlen(server_version_string)) + != strlen(server_version_string)) { + logit("Could not write ident string to %s", get_remote_ipaddr()); + 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 (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 @@ -373,26 +419,32 @@ 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); + 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; - switch(remote_major) { + switch (remote_major) { case 1: if (remote_minor == 99) { if (options.protocol & SSH_PROTO_2) @@ -428,17 +480,16 @@ 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) @@ -449,7 +500,7 @@ destroy_sensitive_data(void) key_free(sensitive_data.server_key); sensitive_data.server_key = NULL; } - for(i = 0; i < options.num_host_key_files; i++) { + for (i = 0; i < options.num_host_key_files; i++) { if (sensitive_data.host_keys[i]) { key_free(sensitive_data.host_keys[i]); sensitive_data.host_keys[i] = NULL; @@ -459,36 +510,211 @@ 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]; + struct passwd *pw; + int i; + + /* Enable challenge-response authentication for privilege separation */ + privsep_challenge_enable(); + + for (i = 0; i < 256; i++) + rnd[i] = arc4random(); + 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, + strerror(errno)); + if (chdir("/") == -1) + fatal("chdir(\"/\"): %s", strerror(errno)); + + /* Drop our privileges */ + debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, + (u_int)pw->pw_gid); +#if 0 + /* XXX not ready, too heavy after chroot */ + do_setusercontext(pw); +#else + gidset[0] = pw->pw_gid; + if (setgroups(1, gidset) < 0) + fatal("setgroups: %.100s", strerror(errno)); + permanently_set_uid(pw); +#endif +} + +static 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) +{ +#ifdef DISABLE_FD_PASSING + if (1) { +#else + if (authctxt->pw->pw_uid == 0 || options.use_login) { +#endif + /* File descriptor passing is broken or root login */ + monitor_apply_keystate(pmonitor); + use_privsep = 0; + return; + } + + /* Authentication complete */ + alarm(0); + if (startup_pipe != -1) { + close(startup_pipe); + startup_pipe = -1; + } + + /* 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) { + debug2("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(); + + /* Drop privileges */ + do_setusercontext(authctxt->pw); + + /* 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) { - static char buf[1024]; + Buffer b; + const char *p; + char *ret; int i; - buf[0] = '\0'; - for(i = 0; i < options.num_host_key_files; i++) { + + buffer_init(&b); + for (i = 0; i < options.num_host_key_files; i++) { Key *key = sensitive_data.host_keys[i]; if (key == NULL) continue; - switch(key->type) { + switch (key->type) { case KEY_RSA: case KEY_DSA: - strlcat(buf, key_ssh_name(key), sizeof buf); - strlcat(buf, ",", sizeof buf); + if (buffer_len(&b) > 0) + buffer_append(&b, ",", 1); + p = key_ssh_name(key); + buffer_append(&b, p, strlen(p)); break; } } - i = strlen(buf); - if (i > 0 && buf[i-1] == ',') - buf[i-1] = '\0'; - debug("list_hostkey_types: %s", buf); - return buf; + buffer_append(&b, "\0", 1); + ret = xstrdup(buffer_ptr(&b)); + buffer_free(&b); + 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++) { + + for (i = 0; i < options.num_host_key_files; i++) { Key *key = sensitive_data.host_keys[i]; if (key != NULL && key->type == type) return key; @@ -496,6 +722,26 @@ 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 @@ -505,7 +751,7 @@ 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; @@ -516,17 +762,106 @@ 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() % 100; - debug("drop_connection: p %g, r %g", p, r); + debug("drop_connection: p %d, r %d", p, r); return (r < p) ? 1 : 0; } -int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */ -int startup_pipe; /* in child */ +static void +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" + ); + exit(1); +} + +static void +send_rexec_state(int fd, Buffer *conf) +{ + Buffer m; + + debug3("%s: entering fd = %d config len %d", __func__, fd, + buffer_len(conf)); + + /* + * 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 " + */ + 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); + + if (ssh_msg_send(fd, 0, &m) == -1) + fatal("%s: ssh_msg_send failed", __func__); + + buffer_free(&m); + + debug3("%s: done", __func__); +} + +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); + } + buffer_free(&m); + + debug3("%s: done", __func__); +} /* * Main program for the daemon. @@ -536,7 +871,8 @@ main(int ac, char **av) { extern char *optarg; extern int optind; - int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1; + int opt, j, i, fdsetsz, on = 1; + int sock_in = -1, sock_out = -1, newsock = -1; pid_t pid; socklen_t fromlen; fd_set *fdset; @@ -544,47 +880,61 @@ main(int ac, char **av) const char *remote_ip; int remote_port; FILE *f; - struct linger linger; struct addrinfo *ai; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + char *line; int listen_sock, maxfd; - int startup_p[2]; + int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; int startups = 0; Key *key; + Authctxt *authctxt; int ret, key_used = 0; + Buffer cfg; - __progname = get_progname(av[0]); +#ifdef HAVE_SECUREWARE + (void)set_auth_parameters(ac, av); +#endif + __progname = ssh_get_progname(av[0]); init_rng(); - /* Save argv. */ + /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ saved_argc = ac; - saved_argv = av; + rexec_argc = ac; + saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); + for (i = 0; i < ac; i++) + saved_argv[i] = xstrdup(av[i]); + saved_argv[i] = NULL; + +#ifndef HAVE_SETPROCTITLE + /* Prepare for later setproctitle emulation */ + compat_init_setproctitle(ac, av); + av = saved_argv; +#endif + + if (geteuid() == 0 && setgroups(0, NULL) == -1) + debug("setgroups(): %.200s", strerror(errno)); /* Initialize configuration options to their default values. */ initialize_server_options(&options); /* Parse command-line arguments. */ - while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDeiqtQ46")) != -1) { + while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { switch (opt) { case '4': - IPv4or6 = AF_INET; + options.address_family = AF_INET; break; case '6': - IPv4or6 = AF_INET6; + options.address_family = AF_INET6; break; case 'f': config_file_name = optarg; break; case 'd': - if (0 == debug_flag) { + if (debug_flag == 0) { debug_flag = 1; options.log_level = SYSLOG_LEVEL_DEBUG1; - } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) { + } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) options.log_level++; - } else { - fprintf(stderr, "Too high debugging level.\n"); - exit(1); - } break; case 'D': no_daemon_flag = 1; @@ -595,6 +945,13 @@ main(int ac, char **av) 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; @@ -635,54 +992,60 @@ main(int ac, char **av) } options.host_key_files[options.num_host_key_files++] = optarg; break; - case 'V': - client_version_string = optarg; - /* only makes sense with inetd_flag, i.e. no listen() */ - inetd_flag = 1; - break; case 't': test_flag = 1; break; case 'u': utmp_len = atoi(optarg); + if (utmp_len > MAXHOSTNAMELEN) { + fprintf(stderr, "Invalid utmp length.\n"); + exit(1); + } + break; + case 'o': + line = xstrdup(optarg); + if (process_server_config_line(&options, line, + "command-line", 0) != 0) + exit(1); + xfree(line); break; case '?': default: - 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"); - exit(1); + usage(); + break; } } + if (rexeced_flag || inetd_flag) + rexec_flag = 0; + if (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(); - channel_set_af(IPv4or6); /* * Force logging to stderr until we have loaded the private host * key (unless started from inetd) */ log_init(__progname, - options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, - options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility, - !inetd_flag); + 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); -#ifdef _CRAY - /* Cray can define user privs drop all prives now! + /* + * 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(); @@ -690,30 +1053,45 @@ main(int ac, char **av) seed_rng(); - /* Read server configuration options from the configuration file. */ - read_server_config(&options, config_file_name); + sensitive_data.server_key = NULL; + sensitive_data.ssh1_host_key = NULL; + sensitive_data.have_ssh1_key = 0; + sensitive_data.have_ssh2_key = 0; + + /* 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); + + if (!rexec_flag) + buffer_free(&cfg); /* Fill in default values for those options not explicitly set. */ fill_default_server_options(&options); + /* 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); /* load private host keys */ - sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*)); - for(i = 0; i < options.num_host_key_files; i++) + sensitive_data.host_keys = xmalloc(options.num_host_key_files * + sizeof(Key *)); + for (i = 0; i < options.num_host_key_files; i++) sensitive_data.host_keys[i] = NULL; - sensitive_data.server_key = NULL; - 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++) { + for (i = 0; i < options.num_host_key_files; i++) { key = key_load_private(options.host_key_files[i], "", NULL); sensitive_data.host_keys[i] = key; if (key == NULL) { @@ -722,7 +1100,7 @@ main(int ac, char **av) sensitive_data.host_keys[i] = NULL; continue; } - switch(key->type){ + switch (key->type) { case KEY_RSA1: sensitive_data.ssh1_host_key = key; sensitive_data.have_ssh1_key = 1; @@ -736,15 +1114,15 @@ main(int ac, char **av) key_type(key)); } if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { - log("Disabling protocol version 1. Could not load host key"); + logit("Disabling protocol version 1. Could not load host key"); options.protocol &= ~SSH_PROTO_1; } if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { - log("Disabling protocol version 2. Could not load host key"); + logit("Disabling protocol version 2. Could not load host key"); options.protocol &= ~SSH_PROTO_2; } if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { - log("sshd: no hostkeys available -- exiting."); + logit("sshd: no hostkeys available -- exiting."); exit(1); } @@ -761,26 +1139,67 @@ main(int ac, char **av) * hate software patents. I dont know if this can go? Niels */ if (options.server_key_bits > - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED && - options.server_key_bits < - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - + SSH_KEY_BITS_RESERVED && options.server_key_bits < + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + + SSH_KEY_BITS_RESERVED) { options.server_key_bits = - BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED; + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + + SSH_KEY_BITS_RESERVED; debug("Forcing server key to %d bits to make it differ from host key.", options.server_key_bits); } } + if (use_privsep) { + struct passwd *pw; + struct stat st; + + if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) + fatal("Privilege separation user %s does not exist", + SSH_PRIVSEP_USER); + if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || + (S_ISDIR(st.st_mode) == 0)) + fatal("Missing privilege separation directory: %s", + _PATH_PRIVSEP_CHROOT_DIR); + +#ifdef HAVE_CYGWIN + if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && + (st.st_uid != getuid () || + (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) +#else + if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) +#endif + fatal("%s must be owned by root and not group or " + "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); + } + /* Configuration looks good, so exit if in test mode. */ if (test_flag) exit(0); -#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 = xmalloc(sizeof(char *) * (rexec_argc + 2)); + 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; + } /* 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); @@ -814,25 +1233,40 @@ main(int ac, char **av) /* Chdir to the root directory so that the current disk can be unmounted if desired. */ chdir("/"); - + /* ignore SIGPIPE */ signal(SIGPIPE, SIG_IGN); /* Start listening for a socket, unless started from inetd. */ 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); + 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 + * 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); - if (options.protocol & SSH_PROTO_1) + if ((options.protocol & SSH_PROTO_1) && + sensitive_data.server_key == NULL) generate_ephemeral_server_key(); } else { for (ai = options.listen_addrs; ai; ai = ai->ai_next) { @@ -841,36 +1275,33 @@ main(int ac, char **av) if (num_listen_socks >= MAX_LISTEN_SOCKS) fatal("Too many listen sockets. " "Enlarge MAX_LISTEN_SOCKS"); - if (getnameinfo(ai->ai_addr, ai->ai_addrlen, + if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), - NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("getnameinfo failed"); + NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { + error("getnameinfo failed: %.100s", + (ret != EAI_SYSTEM) ? gai_strerror(ret) : + strerror(errno)); continue; } /* Create socket for listening. */ - listen_sock = socket(ai->ai_family, SOCK_STREAM, 0); + listen_sock = socket(ai->ai_family, ai->ai_socktype, + ai->ai_protocol); if (listen_sock < 0) { /* kernel may not support ipv6 */ verbose("socket: %.100s", strerror(errno)); continue; } - if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) { - error("listen_sock O_NONBLOCK: %s", strerror(errno)); + if (set_nonblock(listen_sock) == -1) { 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. + * Set socket options. + * Allow local port reuse in TIME_WAIT. */ - setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, - (void *) &on, sizeof(on)); - linger.l_onoff = 1; - linger.l_linger = 5; - setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, - (void *) &linger, sizeof(linger)); + if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, + &on, sizeof(on)) == -1) + error("setsockopt SO_REUSEADDR: %s", strerror(errno)); debug("Bind to port %s on %s.", strport, ntop); @@ -886,8 +1317,8 @@ main(int ac, char **av) num_listen_socks++; /* Start listening on the port. */ - log("Server listening on %s port %s.", ntop, strport); - if (listen(listen_sock, 5) < 0) + logit("Server listening on %s port %s.", ntop, strport); + if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) fatal("listen: %.100s", strerror(errno)); } @@ -921,8 +1352,11 @@ main(int ac, char **av) * overwrite any old pid in the file. */ f = fopen(options.pid_file, "wb"); - if (f) { - fprintf(f, "%u\n", (u_int) getpid()); + 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); } } @@ -962,8 +1396,8 @@ main(int ac, char **av) if (ret < 0 && errno != EINTR) error("select: %.100s", strerror(errno)); if (received_sigterm) { - log("Received signal %d; terminating.", - received_sigterm); + logit("Received signal %d; terminating.", + (int) received_sigterm); close_listen_socks(); unlink(options.pid_file); exit(255); @@ -1000,8 +1434,8 @@ main(int ac, char **av) error("accept: %.100s", strerror(errno)); continue; } - if (fcntl(newsock, F_SETFL, 0) < 0) { - error("newsock del O_NONBLOCK: %s", strerror(errno)); + if (unset_nonblock(newsock) == -1) { + close(newsock); continue; } if (drop_connection(startups) == 1) { @@ -1014,6 +1448,16 @@ main(int ac, char **av) 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]; @@ -1037,8 +1481,15 @@ main(int ac, char **av) 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; } else { /* @@ -1055,13 +1506,13 @@ main(int ac, char **av) * the connection. */ startup_pipe = startup_p[1]; - for (j = 0; j < options.max_startups; j++) - if (startup_pipes[j] != -1) - close(startup_pipes[j]); + 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; } } @@ -1070,10 +1521,16 @@ main(int ac, char **av) if (pid < 0) error("fork: %.100s", strerror(errno)); else - debug("Forked child %d.", pid); + debug("Forked child %ld.", (long)pid); close(startup_p[1]); + 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) { @@ -1095,6 +1552,62 @@ 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 + * 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 + + if (rexec_flag) { + int fd; + + 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]); + } /* * Disable the key regeneration alarm. We will not regenerate the @@ -1109,34 +1622,30 @@ 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, (void *) &linger, sizeof(linger)); - - /* Set keepalives if requested. */ - if (options.keepalives && - setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&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)); - remote_port = get_remote_port(); + if ((remote_port = get_remote_port()) < 0) { + debug("get_remote_port failed"); + cleanup_exit(255); + } remote_ip = get_remote_ipaddr(); +#ifdef SSH_AUDIT_EVENTS + audit_connection_from(remote_ip, remote_port); +#endif #ifdef LIBWRAP /* 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); @@ -1167,56 +1676,126 @@ 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 (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(); + /* allocate authentication context */ + authctxt = xmalloc(sizeof(*authctxt)); + memset(authctxt, 0, 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: +#ifdef SSH_AUDIT_EVENTS + audit_event(SSH_AUTH_SUCCESS); +#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(); + } + + /* Start session. */ + do_authenticated(authctxt); + /* The connection has been terminated. */ verbose("Closing connection to %.100s", remote_ip); #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 */ @@ -1224,13 +1803,12 @@ static void do_ssh1_kex(void) { int i, len; - int plen, slen; int rsafail = 0; BIGNUM *session_key_int; u_char session_key[SSH_SESSION_KEY_LENGTH]; u_char cookie[8]; u_int cipher_type, auth_mask, protocol_flags; - u_int32_t rand = 0; + u_int32_t rnd = 0; /* * Generate check bytes that the client must send back in the user @@ -1243,9 +1821,9 @@ do_ssh1_kex(void) */ for (i = 0; i < 8; i++) { if (i % 4 == 0) - rand = arc4random(); - cookie[i] = rand & 0xff; - rand >>= 8; + rnd = arc4random(); + cookie[i] = rnd & 0xff; + rnd >>= 8; } /* @@ -1275,24 +1853,10 @@ 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) @@ -1308,7 +1872,7 @@ do_ssh1_kex(void) BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); /* Read clients reply (cipher type and session key). */ - packet_read_expect(&plen, SSH_CMSG_SESSION_KEY); + packet_read_expect(SSH_CMSG_SESSION_KEY); /* Get cipher type and check whether we accept this. */ cipher_type = packet_get_char(); @@ -1325,51 +1889,17 @@ do_ssh1_kex(void) debug("Encryption type: %.200s", cipher_name(cipher_type)); /* Get the encrypted integer. */ - session_key_int = BN_new(); - packet_get_bignum(session_key_int, &slen); + if ((session_key_int = BN_new()) == NULL) + fatal("do_ssh1_kex: BN_new failed"); + packet_get_bignum(session_key_int); protocol_flags = packet_get_int(); 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 @@ -1378,7 +1908,7 @@ do_ssh1_kex(void) if (!rsafail) { BN_mask_bits(session_key_int, sizeof(session_key) * 8); len = BN_num_bytes(session_key_int); - if (len < 0 || len > sizeof(session_key)) { + if (len < 0 || (u_int)len > sizeof(session_key)) { error("do_connection: bad session key len from %s: " "session_key_int %d > sizeof(session_key) %lu", get_remote_ipaddr(), len, (u_long)sizeof(session_key)); @@ -1388,9 +1918,10 @@ 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. @@ -1401,10 +1932,10 @@ do_ssh1_kex(void) } if (rsafail) { int bytes = BN_num_bytes(session_key_int); - char *buf = xmalloc(bytes); + 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); @@ -1420,9 +1951,12 @@ 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); @@ -1434,7 +1968,7 @@ 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(); @@ -1461,14 +1995,26 @@ 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(); /* 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->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; @@ -1486,3 +2032,17 @@ 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); +}