RETSIGTYPE key_regeneration_alarm(int sig)
{
/* Check if we should generate a new key. */
if (key_used) {
/* This should really be done in the background. */
log_msg("Generating new %d bit RSA key.", options.server_key_bits);
random_acquire_light_environmental_noise(&sensitive_data.random_state);
rsa_generate_key(&sensitive_data.private_key, &public_key, &sensitive_data.random_state, options.server_key_bits);
random_save(&sensitive_data.random_state, geteuid(), options.random_seed_file);
key_used = 0;
log_msg("RSA key generation complete.");
}
/* Reschedule the alarm. */
signal(SIGALRM, key_regeneration_alarm);
alarm(options.key_regeneration_time);
}
nyx_error_t security_create_rsa_key(nyx_device_handle_t d, int keylen,
int *key_index)
{
return rsa_generate_key(keylen, key_index);
}
int main(int ac, char **av)
{
extern char *optarg;
extern int optind;
int opt, sock_in, sock_out, newsock, i, pid = 0, on = 1;
socklen_t aux;
int remote_major, remote_minor;
int perm_denied = 0;
int ret;
fd_set fdset;
#ifdef HAVE_IPV6_SMTH
struct sockaddr_in6 sin;
#else
struct sockaddr_in sin;
#endif
char buf[100]; /* Must not be larger than remote_version. */
char remote_version[100]; /* Must be at least as big as buf. */
char addr[STRLEN];
char *comment;
char *ssh_remote_version_string = NULL;
FILE *f;
#if defined(SO_LINGER) && defined(ENABLE_SO_LINGER)
struct linger linger;
#endif /* SO_LINGER */
int done;
chdir(BBSHOME);
/* Save argv[0]. */
saved_argv = av;
if (strchr(av[0], '/'))
av0 = strrchr(av[0], '/') + 1;
else
av0 = av[0];
/* Prevent core dumps to avoid revealing sensitive information. */
signals_prevent_core();
/* Set SIGPIPE to be ignored. */
signal(SIGPIPE, SIG_IGN);
/* Initialize configuration options to their default values. */
initialize_server_options(&options);
addr[0]=0;
/* Parse command-line arguments. */
while ((opt = getopt(ac, av, "f:a:p:b:k:h:g:diqV:")) != EOF) {
switch (opt) {
case 'f':
config_file_name = optarg;
break;
case 'd':
debug_flag = 1;
break;
case 'i':
inetd_flag = 1;
break;
case 'q':
options.quiet_mode = 1;
break;
case 'b':
options.server_key_bits = atoi(optarg);
break;
case 'a':
if(optarg[0])
snprintf(addr,STRLEN,"%s",optarg);
break;
case 'p':
if(isdigit(optarg[0]))
options.port=atoi(optarg);
break;
case 'g':
options.login_grace_time = atoi(optarg);
break;
case 'k':
options.key_regeneration_time = atoi(optarg);
break;
case 'h':
options.host_key_file = optarg;
break;
case 'V':
ssh_remote_version_string = optarg;
break;
case '?':
default:
#ifdef F_SECURE_COMMERCIAL
#endif /* F_SECURE_COMMERCIAL */
fprintf(stderr, "sshd version %s [%s]\n", SSH_VERSION, HOSTTYPE);
fprintf(stderr, "Usage: %s [options]\n", av0);
fprintf(stderr, "Options:\n");
fprintf(stderr, " -f file Configuration file (default %s/sshd_config)\n", ETCDIR);
fprintf(stderr, " -d Debugging mode\n");
fprintf(stderr, " -i Started from inetd\n");
fprintf(stderr, " -q Quiet (no logging)\n");
fprintf(stderr, " -a addr Bind to the specified address (default: all)\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: 300)\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", HOST_KEY_FILE);
fprintf(stderr, " -V str Remote version string already read from the socket\n");
exit(1);
}
}
/* Read server configuration options from the configuration file. */
read_server_config(&options, config_file_name);
/* Fill in default values for those options not explicitly set. */
fill_default_server_options(&options);
/* Check certain values for sanity. */
if (options.server_key_bits < 512 || options.server_key_bits > 32768) {
fprintf(stderr, "fatal: Bad server key size.\n");
exit(1);
}
if (options.port < 1 || options.port > 65535) {
fprintf(stderr, "fatal: Bad port number.\n");
exit(1);
}
if (options.umask != -1) {
umask(options.umask);
}
/* Check that there are no remaining arguments. */
if (optind < ac) {
fprintf(stderr, "fatal: Extra argument %.100s.\n", av[optind]);
exit(1);
}
/* Initialize the log (it is reinitialized below in case we forked). */
log_init(av0, debug_flag && !inetd_flag, debug_flag || options.fascist_logging, options.quiet_mode, options.log_facility);
debug("sshd version %.100s [%.100s]", SSH_VERSION, HOSTTYPE);
/* Load the host key. It must have empty passphrase. */
done = load_private_key(geteuid(), options.host_key_file, "", &sensitive_data.host_key, &comment);
if (!done) {
if (debug_flag) {
fprintf(stderr, "Could not load host key: %.200s\n", options.host_key_file);
fprintf(stderr, "fatal: Please check that you have sufficient permissions and the file exists.\n");
} else {
log_init(av0, !inetd_flag, 1, 0, options.log_facility);
error("fatal: Could not load host key: %.200s. Check path and permissions.", options.host_key_file);
}
exit(1);
}
xfree(comment);
/* If not in debugging mode, and not started from inetd, disconnect from
the controlling terminal, and fork. The original process exits. */
if (!debug_flag && !inetd_flag)
#ifdef HAVE_DAEMON
if (daemon(0, 0) < 0)
error("daemon: %.100s", strerror(errno));
chdir(BBSHOME);
#else /* HAVE_DAEMON */
{
#ifdef TIOCNOTTY
int fd;
#endif /* TIOCNOTTY */
/* Fork, and have the parent exit. The child becomes the server. */
if (fork())
exit(0);
/* Redirect stdin, stdout, and stderr to /dev/null. */
freopen("/dev/null", "r", stdin);
freopen("/dev/null", "w", stdout);
freopen("/dev/null", "w", stderr);
/* Disconnect from the controlling tty. */
#ifdef TIOCNOTTY
fd = open("/dev/tty", O_RDWR | O_NOCTTY);
if (fd >= 0) {
(void) ioctl(fd, TIOCNOTTY, NULL);
close(fd);
}
#endif /* TIOCNOTTY */
#ifdef HAVE_SETSID
#ifdef ultrix
setpgrp(0, 0);
#else /* ultrix */
if (setsid() < 0)
error("setsid: %.100s", strerror(errno));
#endif
#endif /* HAVE_SETSID */
}
#endif /* HAVE_DAEMON */
/* Reinitialize the log (because of the fork above). */
log_init(av0, debug_flag && !inetd_flag, debug_flag || options.fascist_logging, options.quiet_mode, options.log_facility);
/* Check that server and host key lengths differ sufficiently. This is
necessary to make double encryption work with rsaref. Oh, I hate
software patents. */
if (options.server_key_bits > sensitive_data.host_key.bits - SSH_KEY_BITS_RESERVED && options.server_key_bits < sensitive_data.host_key.bits + SSH_KEY_BITS_RESERVED) {
options.server_key_bits = sensitive_data.host_key.bits + SSH_KEY_BITS_RESERVED;
debug("Forcing server key to %d bits to make it differ from host key.", options.server_key_bits);
}
/* Initialize memory allocation so that any freed MP_INT data will be
zeroed. */
rsa_set_mp_memory_allocation();
/* Do not display messages to stdout in RSA code. */
rsa_set_verbose(debug_flag);
/* Initialize the random number generator. */
debug("Initializing random number generator; seed file %.200s", options.random_seed_file);
random_initialize(&sensitive_data.random_state, geteuid(), options.random_seed_file);
/* Chdir to the root directory so that the current disk can be unmounted
if desired. */
idle_timeout = options.idle_timeout;
/* Start listening for a socket, unless started from inetd. */
if (inetd_flag) {
int s1, s2;
s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
s2 = dup(s1);
sock_in = dup(0);
sock_out = dup(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);
/* Generate an rsa key. */
log_msg("Generating %d bit RSA key.", options.server_key_bits);
rsa_generate_key(&sensitive_data.private_key, &public_key, &sensitive_data.random_state, options.server_key_bits);
random_save(&sensitive_data.random_state, geteuid(), options.random_seed_file);
log_msg("RSA key generation complete.");
} else {
/* Create socket for listening. */
#ifdef HAVE_IPV6_SMTH
listen_sock = socket(AF_INET6, SOCK_STREAM, 0);
#else
listen_sock = socket(AF_INET, SOCK_STREAM, 0);
#endif
if (listen_sock < 0)
fatal("socket: %.100s", strerror(errno));
/* 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, (void *) &on, sizeof(on));
#if defined(SO_LINGER) && defined(ENABLE_SO_LINGER)
linger.l_onoff = 1;
linger.l_linger = 15;
setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
#endif /* SO_LINGER */
/* Initialize the socket address. */
memset(&sin, 0, sizeof(sin));
#ifdef HAVE_IPV6_SMTH
sin.sin6_family = AF_INET6;
if ( inet_pton(AF_INET6, addr, &(sin.sin6_addr)) <= 0 )
sin.sin6_addr = in6addr_any;
sin.sin6_port = htons(options.port);
#else
sin.sin_family = AF_INET;
if ( inet_pton(AF_INET, addr, &(sin.sin_addr)) <= 0 )
sin.sin_addr.s_addr = htonl(INADDR_ANY);
sin.sin_port = htons(options.port);
#endif
/* Bind the socket to the desired port. */
if (bind(listen_sock, (struct sockaddr *) &sin, sizeof(sin)) < 0) {
error("bind: %.100s", strerror(errno));
shutdown(listen_sock, 2);
close(listen_sock);
fatal("Bind to port %d failed: %.200s.", options.port, strerror(errno));
}
/* COMMAN : setuid to bbs */
if(setgid(BBSGID)==-1)
exit(8);
if(setuid(BBSUID)==-1)
exit(8);
#if 0 /* etnlegend, 2006.10.31 ... */
if (!debug_flag) {
/* Record our pid in /etc/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, "w");
if (f) {
fprintf(f, "%u\n", (unsigned int) getpid());
fclose(f);
}
}
#endif
/* Start listening on the port. */
log_msg("Server listening on port %d.", options.port);
if (listen(listen_sock, 5) < 0)
fatal("listen: %.100s", strerror(errno));
/* Generate an rsa key. */
log_msg("Generating %d bit RSA key.", options.server_key_bits);
rsa_generate_key(&sensitive_data.private_key, &public_key, &sensitive_data.random_state, options.server_key_bits);
random_save(&sensitive_data.random_state, geteuid(), options.random_seed_file);
log_msg("RSA key generation complete.");
/* Schedule server key regeneration alarm. */
signal(SIGALRM, key_regeneration_alarm);
alarm(options.key_regeneration_time);
/* Arrange to restart on SIGHUP. The handler needs listen_sock. */
signal(SIGHUP, sighup_handler);
signal(SIGTERM, sigterm_handler);
signal(SIGQUIT, sigterm_handler);
/* AIX sends SIGDANGER when memory runs low. The default action is
to terminate the process. This sometimes makes it difficult to
log in and fix the problem. */
#ifdef SIGDANGER
signal(SIGDANGER, sigdanger_handler);
#endif /* SIGDANGER */
/* Arrange SIGCHLD to be caught. */
signal(SIGCHLD, main_sigchld_handler);
if(!debug_flag){
if(!addr[0])
sprintf(buf,"var/sshbbsd.%d.pid",options.port);
else
sprintf(buf,"var/sshbbsd.%d_%s.pid",options.port,addr);
if((f=fopen(buf,"w"))){
fprintf(f,"%d\n",(int)getpid());
fclose(f);
}
}
/* Stay listening for connections until the system crashes or the
daemon is killed with a signal. */
for (;;) {
if (received_sighup)
sighup_restart();
/* Wait in select until there is a connection. */
FD_ZERO(&fdset);
FD_SET(listen_sock, &fdset);
ret = select(listen_sock + 1, &fdset, NULL, NULL, NULL);
if (ret < 0 || !FD_ISSET(listen_sock, &fdset)) {
if (errno == EINTR)
continue;
error("select: %.100s", strerror(errno));
continue;
}
aux = sizeof(sin);
newsock = accept(listen_sock, (struct sockaddr *) &sin, &aux);
if (newsock < 0) {
if (errno == EINTR)
continue;
error("accept: %.100s", strerror(errno));
continue;
}
/* 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_sock);
sock_in = newsock;
sock_out = newsock;
pid = getpid();
#ifdef LIBWRAP
{
struct request_info req;
signal(SIGCHLD, SIG_DFL);
request_init(&req, RQ_DAEMON, av0, RQ_FILE, newsock, NULL);
fromhost(&req);
if (!hosts_access(&req))
refuse(&req);
syslog(allow_severity, "connect from %s", eval_client(&req));
}
#endif /* LIBWRAP */
break;
} else {
#ifdef CHECK_IP_LINK
#ifdef HAVE_IPV6_SMTH
if (check_IP_lists(sin.sin6_addr)==0)
#else
if (check_IP_lists(sin.sin_addr.s_addr)==0)
#endif
#endif
/* Normal production daemon. Fork, and have the child process
the connection. The parent continues listening. */
if ((pid = fork()) == 0) {
/* Child. Close the listening socket, and start using
the accepted socket. Reinitialize logging (since our
pid has changed). We break out of the loop to handle
the connection. */
close(listen_sock);
sock_in = newsock;
sock_out = newsock;
#ifdef LIBWRAP
{
struct request_info req;
signal(SIGCHLD, SIG_DFL);
request_init(&req, RQ_DAEMON, av0, RQ_FILE, newsock, NULL);
fromhost(&req);
if (!hosts_access(&req))
refuse(&req);
syslog(allow_severity, "connect from %s", eval_client(&req));
}
#endif /* LIBWRAP */
log_init(av0, debug_flag && !inetd_flag, options.fascist_logging || debug_flag, options.quiet_mode, options.log_facility);
break;
}
}
/* Parent. Stay in the loop. */
if (pid < 0)
error("fork: %.100s", strerror(errno));
else
debug("Forked child %d.", pid);
/* Mark that the key has been used (it was "given" to the child). */
key_used = 1;
random_acquire_light_environmental_noise(&sensitive_data.random_state);
/* Close the new socket (the child is now taking care of it). */
close(newsock);
}
}
/* 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 will
not restart on SIGHUP since it no longer makes sense. */
alarm(0);
signal(SIGALRM, SIG_DFL);
signal(SIGHUP, SIG_DFL);
signal(SIGTERM, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGCHLD, 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)); */
#if defined(SO_LINGER) && defined(ENABLE_SO_LINGER)
linger.l_onoff = 1;
linger.l_linger = 15;
setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
#endif /* SO_LINGER */
/* Register our connection. This turns encryption off because we do not
have a key. */
packet_set_connection(sock_in, sock_out, &sensitive_data.random_state);
/* Log the connection. */
log_msg("Connection from %.100s port %d", get_remote_ipaddr(), get_remote_port());
/* Check whether logins are denied from this host. */
{
const char *hostname = get_canonical_hostname();
const char *ipaddr = get_remote_ipaddr();
int i;
if (options.num_deny_hosts > 0) {
for (i = 0; i < options.num_deny_hosts; i++)
if (match_host(hostname, ipaddr, options.deny_hosts[i]))
perm_denied = 1;
}
if ((!perm_denied) && options.num_allow_hosts > 0) {
for (i = 0; i < options.num_allow_hosts; i++)
if (match_host(hostname, ipaddr, options.allow_hosts[i]))
break;
if (i >= options.num_allow_hosts)
perm_denied = 1;
}
if (perm_denied && options.silent_deny) {
close(sock_in);
close(sock_out);
exit(0);
}
}
/* 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 mode; it is just annoying
to have the server exit just when you are about to discover the bug. */
signal(SIGALRM, grace_alarm_handler);
if (!debug_flag)
alarm(options.login_grace_time);
if (ssh_remote_version_string == NULL) {
/* Send our protocol version identification. */
snprintf(buf, sizeof(buf), "SSH-%d.%d-%.50s", PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
strcat(buf, "\n");
if (write(sock_out, buf, strlen(buf)) != strlen(buf))
fatal_severity(SYSLOG_SEVERITY_INFO, "Could not write ident string.");
}
if (ssh_remote_version_string == NULL) {
/* Read other side\'s version identification. */
for (i = 0; i < sizeof(buf) - 1; i++) {
if (read(sock_in, &buf[i], 1) != 1)
fatal_severity(SYSLOG_SEVERITY_INFO, "Did not receive ident string.");
if (buf[i] == '\r') {
buf[i] = '\n';
buf[i + 1] = 0;
break;
}
if (buf[i] == '\n') {
/* buf[i] == '\n' */
buf[i + 1] = 0;
break;
}
}
buf[sizeof(buf) - 1] = 0;
} else {
strncpy(buf, ssh_remote_version_string, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = 0;
}
/* Check that the versions match. In future this might accept several
versions and set appropriate flags to handle them. */
if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, remote_version) != 3) {
const char *s = "Protocol mismatch.\n";
(void) write(sock_out, s, strlen(s));
close(sock_in);
close(sock_out);
fatal_severity(SYSLOG_SEVERITY_INFO, "Bad protocol version identification: %.100s", buf);
}
debug("Client protocol version %d.%d; client software version %.100s", remote_major, remote_minor, remote_version);
switch (check_emulation(remote_major, remote_minor, NULL, NULL)) {
case EMULATE_MAJOR_VERSION_MISMATCH:
{
const char *s = "Protocol major versions differ.\n";
(void) write(sock_out, s, strlen(s));
close(sock_in);
close(sock_out);
fatal_severity(SYSLOG_SEVERITY_INFO, "Protocol major versions differ: %d vs. %d", PROTOCOL_MAJOR, remote_major);
}
break;
case EMULATE_VERSION_TOO_OLD:
packet_disconnect("Your ssh version is too old and is no " "longer supported. Please install a newer version.");
break;
case EMULATE_VERSION_NEWER:
packet_disconnect("This server does not support your " "new ssh version.");
break;
case EMULATE_VERSION_OK:
break;
default:
fatal("Unexpected return value from check_emulation.");
}
if (perm_denied) {
const char *hostname = get_canonical_hostname();
log_msg("Connection from %.200s not allowed.\n", hostname);
packet_disconnect("Sorry, you are not allowed to connect.");
/*NOTREACHED*/}
packet_set_nonblocking();
/* Handle the connection. We pass as argument whether the connection
came from a privileged port. */
do_connection(get_remote_port() < 1024);
/* The connection has been terminated. */
log_msg("Closing connection to %.100s", get_remote_ipaddr());
packet_close();
exit(0);
}
