* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
- * Created: Fri Mar 17 17:09:28 1995 ylo
- * This program is the ssh daemon. It listens for connections from clients, and
- * performs authentication, executes use commands or shell, and forwards
+ * This program is the ssh daemon. It listens for connections from clients,
+ * and performs authentication, executes use commands or shell, and forwards
* information to/from the application to the user client over an encrypted
- * connection. This can also handle forwarding of X11, TCP/IP, and authentication
- * agent connections.
+ * connection. This can also handle forwarding of X11, TCP/IP, and
+ * authentication agent connections.
*
- * SSH2 implementation,
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose. Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ * SSH2 implementation:
+ *
+ * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.105 2000/04/14 10:30:33 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.132 2000/10/13 18:34:46 markus Exp $");
#include "xmalloc.h"
#include "rsa.h"
#include "ssh.h"
#include "pty.h"
#include "packet.h"
-#include "cipher.h"
#include "mpaux.h"
#include "servconf.h"
#include "uidswap.h"
#include <openssl/rsa.h>
#include "key.h"
#include "dsa.h"
+#include "dh.h"
#include "auth.h"
#include "myproposal.h"
+#include "authfile.h"
#ifdef LIBWRAP
#include <tcpd.h>
/* Saved arguments to main(). */
char **saved_argv;
+int saved_argc;
/*
* The sockets that the server is listening; this is used in the SIGHUP
* not very useful. Currently, memory locking is not implemented.
*/
struct {
- RSA *private_key; /* Private part of server key. */
+ RSA *private_key; /* Private part of empheral server key. */
RSA *host_key; /* Private part of host key. */
+ Key *dsa_host_key; /* Private DSA host key. */
} sensitive_data;
/*
/* session identifier, used by RSA-auth */
unsigned char session_id[16];
+/* same for ssh2 */
+unsigned char *session_id2 = NULL;
+int session_id2_len = 0;
+
+/* record remote hostname or ip */
+unsigned int utmp_len = MAXHOSTNAMELEN;
+
/* Prototypes for various functions defined later in this file. */
void do_ssh1_kex();
void do_ssh2_kex();
+void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *);
+void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *);
+
/*
* Close all listening sockets
*/
{
log("Received signal %d; terminating.", sig);
close_listen_socks();
+ unlink(options.pid_file);
exit(255);
}
* Thus there should be no concurrency control/asynchronous execution
* problems.
*/
+/* XXX do we really want this work to be done in a signal handler ? -m */
void
key_regeneration_alarm(int sig)
{
errno = save_errno;
}
-char *
-chop(char *s)
-{
- char *t = s;
- while (*t) {
- if(*t == '\n' || *t == '\r') {
- *t = '\0';
- return s;
- }
- t++;
- }
- return s;
-
-}
-
void
sshd_exchange_identification(int sock_in, int sock_out)
{
/* Read other side\'s version identification. */
for (i = 0; i < sizeof(buf) - 1; i++) {
- if (read(sock_in, &buf[i], 1) != 1) {
+ if (atomicio(read, sock_in, &buf[i], 1) != 1) {
log("Did not receive ident string from %s.", get_remote_ipaddr());
fatal_cleanup();
}
if (buf[i] == '\r') {
buf[i] = '\n';
buf[i + 1] = 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') {
mismatch = 0;
switch(remote_major) {
case 1:
+ if (remote_minor == 99) {
+ if (options.protocol & SSH_PROTO_2)
+ enable_compat20();
+ else
+ mismatch = 1;
+ break;
+ }
if (!(options.protocol & SSH_PROTO_1)) {
mismatch = 1;
break;
}
if (remote_minor < 3) {
- packet_disconnect("Your ssh version is too old and"
+ packet_disconnect("Your ssh version is too old and "
"is no longer supported. Please install a newer version.");
} else if (remote_minor == 3) {
/* note that this disables agent-forwarding */
enable_compat13();
}
- if (remote_minor == 99) {
- if (options.protocol & SSH_PROTO_2)
- enable_compat20();
- else
- mismatch = 1;
- }
break;
case 2:
if (options.protocol & SSH_PROTO_2) {
server_version_string, client_version_string);
fatal_cleanup();
}
+ if (compat20)
+ packet_set_ssh2_format();
+}
+
+
+void
+destroy_sensitive_data(void)
+{
+ /* Destroy the private and public keys. They will no longer be needed. */
+ if (public_key)
+ RSA_free(public_key);
+ if (sensitive_data.private_key)
+ RSA_free(sensitive_data.private_key);
+ if (sensitive_data.host_key)
+ RSA_free(sensitive_data.host_key);
+ if (sensitive_data.dsa_host_key != NULL)
+ key_free(sensitive_data.dsa_host_key);
}
+/*
+ * returns 1 if connection should be dropped, 0 otherwise.
+ * dropping starts at connection #max_startups_begin with a probability
+ * of (max_startups_rate/100). the probability increases linearly until
+ * all connections are dropped for startups > max_startups
+ */
+int
+drop_connection(int startups)
+{
+ double p, r;
+
+ if (startups < options.max_startups_begin)
+ return 0;
+ if (startups >= options.max_startups)
+ return 1;
+ if (options.max_startups_rate == 100)
+ return 1;
+
+ 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_rate;
+ p /= 100.0;
+ r = arc4random() / (double) UINT_MAX;
+
+ debug("drop_connection: p %g, r %g", p, r);
+ return (r < p) ? 1 : 0;
+}
+
+int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */
+int startup_pipe; /* in child */
+
/*
* Main program for the daemon.
*/
{
extern char *optarg;
extern int optind;
- int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
+ int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
+ pid_t pid;
socklen_t fromlen;
- int silentrsa = 0;
+ int silent = 0;
fd_set *fdset;
struct sockaddr_storage from;
const char *remote_ip;
int remote_port;
- char *comment;
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;
+
+ init_rng();
/* Save argv[0]. */
+ saved_argc = ac;
saved_argv = av;
if (strchr(av[0], '/'))
av0 = strrchr(av[0], '/') + 1;
initialize_server_options(&options);
/* Parse command-line arguments. */
- while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
+ while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:diqQ46")) != EOF) {
switch (opt) {
case '4':
IPv4or6 = AF_INET;
config_file_name = optarg;
break;
case 'd':
- debug_flag = 1;
- options.log_level = SYSLOG_LEVEL_DEBUG;
+ 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 'i':
inetd_flag = 1;
break;
case 'Q':
- silentrsa = 1;
+ silent = 1;
break;
case 'q':
options.log_level = SYSLOG_LEVEL_QUIET;
break;
case 'p':
options.ports_from_cmdline = 1;
- if (options.num_ports >= MAX_PORTS)
- fatal("too many ports.\n");
+ if (options.num_ports >= MAX_PORTS) {
+ fprintf(stderr, "too many ports.\n");
+ exit(1);
+ }
options.ports[options.num_ports++] = atoi(optarg);
break;
case 'g':
/* only makes sense with inetd_flag, i.e. no listen() */
inetd_flag = 1;
break;
+ case 'u':
+ utmp_len = atoi(optarg);
+ break;
case '?':
default:
fprintf(stderr, "sshd version %s\n", SSH_VERSION);
fprintf(stderr, "Usage: %s [options]\n", av0);
fprintf(stderr, "Options:\n");
fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
- fprintf(stderr, " -d Debugging mode\n");
+ fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
fprintf(stderr, " -i Started from inetd\n");
fprintf(stderr, " -q Quiet (no logging)\n");
fprintf(stderr, " -p port Listen on the specified port (default: 22)\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, " -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);
log_init(av0,
options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
- !inetd_flag);
+ !silent && !inetd_flag);
- /* check if RSA support exists */
- if (rsa_alive() == 0) {
- if (silentrsa == 0)
- printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
- log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
- 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, "Bad server key size.\n");
- exit(1);
- }
/* Check that there are no remaining arguments. */
if (optind < ac) {
fprintf(stderr, "Extra argument %s.\n", av[optind]);
debug("sshd version %.100s", SSH_VERSION);
- sensitive_data.host_key = RSA_new();
- errno = 0;
- /* Load the host key. It must have empty passphrase. */
- if (!load_private_key(options.host_key_file, "",
- sensitive_data.host_key, &comment)) {
- error("Could not load host key: %.200s: %.100s",
- options.host_key_file, strerror(errno));
+ sensitive_data.dsa_host_key = NULL;
+ sensitive_data.host_key = NULL;
+
+ /* check if RSA support exists */
+ if ((options.protocol & SSH_PROTO_1) &&
+ rsa_alive() == 0) {
+ log("no RSA support in libssl and libcrypto. See ssl(8)");
+ log("Disabling protocol version 1");
+ options.protocol &= ~SSH_PROTO_1;
+ }
+ /* Load the RSA/DSA host key. It must have empty passphrase. */
+ if (options.protocol & SSH_PROTO_1) {
+ Key k;
+ sensitive_data.host_key = RSA_new();
+ k.type = KEY_RSA;
+ k.rsa = sensitive_data.host_key;
+ errno = 0;
+ if (!load_private_key(options.host_key_file, "", &k, NULL)) {
+ error("Could not load host key: %.200s: %.100s",
+ options.host_key_file, strerror(errno));
+ log("Disabling protocol version 1");
+ options.protocol &= ~SSH_PROTO_1;
+ }
+ k.rsa = NULL;
+ }
+ if (options.protocol & SSH_PROTO_2) {
+ sensitive_data.dsa_host_key = key_new(KEY_DSA);
+ if (!load_private_key(options.host_dsa_key_file, "", sensitive_data.dsa_host_key, NULL)) {
+
+ error("Could not load DSA host key: %.200s", options.host_dsa_key_file);
+ log("Disabling protocol version 2");
+ options.protocol &= ~SSH_PROTO_2;
+ }
+ }
+ if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) {
+ if (silent == 0)
+ fprintf(stderr, "sshd: no hostkeys available -- exiting.\n");
+ log("sshd: no hostkeys available -- exiting.\n");
exit(1);
}
- xfree(comment);
- /* Initialize the log (it is reinitialized below in case we
- forked). */
+ /* Check certain values for sanity. */
+ if (options.protocol & SSH_PROTO_1) {
+ if (options.server_key_bits < 512 ||
+ options.server_key_bits > 32768) {
+ fprintf(stderr, "Bad server key size.\n");
+ exit(1);
+ }
+ /*
+ * Check that server and host key lengths differ sufficiently. This
+ * is necessary to make double encryption work with rsaref. Oh, I
+ * hate software patents. I dont know if this can go? Niels
+ */
+ if (options.server_key_bits >
+ BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
+ options.server_key_bits <
+ BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
+ options.server_key_bits =
+ BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
+ debug("Forcing server key to %d bits to make it differ from host key.",
+ options.server_key_bits);
+ }
+ }
+
+#ifdef HAVE_SCO_PROTECTED_PW
+ (void) set_auth_parameters(ac, av);
+#endif
+
+ /* Initialize the log (it is reinitialized below in case we forked). */
if (debug_flag && !inetd_flag)
log_stderr = 1;
log_init(av0, options.log_level, options.log_facility, log_stderr);
- /* If not in debugging mode, and not started from inetd,
- disconnect from the controlling terminal, and fork. The
- original process exits. */
+ /*
+ * 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 TIOCNOTTY
int fd;
/* Reinitialize the log (because of the fork above). */
log_init(av0, options.log_level, options.log_facility, log_stderr);
- /* Check that server and host key lengths differ sufficiently.
- This is necessary to make double encryption work with rsaref.
- Oh, I hate software patents. I dont know if this can go? Niels */
- if (options.server_key_bits >
- BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
- options.server_key_bits <
- BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
- options.server_key_bits =
- BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
- debug("Forcing server key to %d bits to make it differ from host key.",
- options.server_key_bits);
- }
/* Do not display messages to stdout in RSA code. */
rsa_set_verbose(0);
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. */
+ 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);
- public_key = RSA_new();
- sensitive_data.private_key = RSA_new();
-
- /* XXX check options.protocol */
- log("Generating %d bit RSA key.", options.server_key_bits);
- rsa_generate_key(sensitive_data.private_key, public_key,
- options.server_key_bits);
- arc4random_stir();
- log("RSA key generation complete.");
+ if (options.protocol & SSH_PROTO_1) {
+ public_key = RSA_new();
+ sensitive_data.private_key = RSA_new();
+ log("Generating %d bit RSA key.", options.server_key_bits);
+ rsa_generate_key(sensitive_data.private_key, public_key,
+ options.server_key_bits);
+ arc4random_stir();
+ log("RSA key generation complete.");
+ }
} else {
for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
* fail if there already is a daemon, and this will
* overwrite any old pid in the file.
*/
- f = fopen(SSH_DAEMON_PID_FILE, "w");
+ f = fopen(options.pid_file, "wb");
if (f) {
fprintf(f, "%u\n", (unsigned int) getpid());
fclose(f);
}
}
+ if (options.protocol & SSH_PROTO_1) {
+ public_key = RSA_new();
+ sensitive_data.private_key = RSA_new();
- public_key = RSA_new();
- sensitive_data.private_key = RSA_new();
-
- log("Generating %d bit RSA key.", options.server_key_bits);
- rsa_generate_key(sensitive_data.private_key, public_key,
- options.server_key_bits);
- arc4random_stir();
- log("RSA key generation complete.");
+ log("Generating %d bit RSA key.", options.server_key_bits);
+ rsa_generate_key(sensitive_data.private_key, public_key,
+ options.server_key_bits);
+ arc4random_stir();
+ log("RSA key generation complete.");
- /* Schedule server key regeneration alarm. */
- signal(SIGALRM, key_regeneration_alarm);
- alarm(options.key_regeneration_time);
+ /* 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);
signal(SIGCHLD, main_sigchld_handler);
/* 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];
- fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
- fdset = (fd_set *)xmalloc(fdsetsz);
+ /* 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
for (;;) {
if (received_sighup)
sighup_restart();
- /* Wait in select until there is a connection. */
+ if (fdset != NULL)
+ xfree(fdset);
+ fdsetsz = howmany(maxfd, 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. */
if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
if (errno != EINTR)
error("select: %.100s", strerror(errno));
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 successfull 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));
- 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_socks();
- sock_in = newsock;
- sock_out = newsock;
- pid = getpid();
- break;
- } else {
+ 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));
+ 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;
+ }
+
/*
- * Normal production daemon. Fork, and have
- * the child process the connection. The
- * parent continues listening.
+ * Got connection. Fork a child to handle it, unless
+ * we are in debugging mode.
*/
- if ((pid = fork()) == 0) {
+ if (debug_flag) {
/*
- * 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.
+ * 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;
- log_init(av0, options.log_level, options.log_facility, log_stderr);
+ 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];
+ for (j = 0; j < options.max_startups; j++)
+ if (startup_pipes[j] != -1)
+ close(startup_pipes[j]);
+ close_listen_socks();
+ sock_in = newsock;
+ sock_out = newsock;
+ log_init(av0, 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);
+ /* 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;
+ close(startup_p[1]);
- arc4random_stir();
+ /* Mark that the key has been used (it was "given" to the child). */
+ key_used = 1;
- /* Close the new socket (the child is now taking care of it). */
- close(newsock);
- } /* for (i = 0; i < num_listen_socks; i++) */
+ arc4random_stir();
+
+ /* 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;
signal(SIGTERM, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGCHLD, SIG_DFL);
+ signal(SIGINT, SIG_DFL);
/*
* Set socket options for the connection. We want the socket to
packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
/* Declare which ciphers we support. */
- packet_put_int(cipher_mask1());
+ packet_put_int(cipher_mask_ssh1(0));
/* Declare supported authentication types. */
auth_mask = 0;
/* Get cipher type and check whether we accept this. */
cipher_type = packet_get_char();
- if (!(cipher_mask() & (1 << cipher_type)))
+ if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
packet_disconnect("Warning: client selects unsupported cipher.");
/* Get check bytes from the packet. These must match those we
sensitive_data.private_key->n);
/* Destroy the private and public keys. They will no longer be needed. */
- RSA_free(public_key);
- RSA_free(sensitive_data.private_key);
- RSA_free(sensitive_data.host_key);
+ destroy_sensitive_data();
/*
* Extract session key from the decrypted integer. The key is in the
if (len < 0 || len > sizeof(session_key))
fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
get_remote_ipaddr(),
- len, sizeof(session_key));
+ len, (int) sizeof(session_key));
memset(session_key, 0, sizeof(session_key));
BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
{
Buffer *server_kexinit;
Buffer *client_kexinit;
- int payload_len, dlen;
- int slen;
- unsigned int klen, kout;
- char *ptr;
- unsigned char *signature = NULL;
- unsigned char *server_host_key_blob = NULL;
- unsigned int sbloblen;
- DH *dh;
- BIGNUM *dh_client_pub = 0;
- BIGNUM *shared_secret = 0;
+ int payload_len;
int i;
- unsigned char *kbuf;
- unsigned char *hash;
Kex *kex;
- Key *server_host_key;
char *cprop[PROPOSAL_MAX];
- char *sprop[PROPOSAL_MAX];
/* KEXINIT */
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
}
+ server_kexinit = kex_init(myproposal);
+ client_kexinit = xmalloc(sizeof(*client_kexinit));
+ buffer_init(client_kexinit);
- debug("Sending KEX init.");
-
+ /* algorithm negotiation */
+ kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
+ kex = kex_choose_conf(cprop, myproposal, 1);
for (i = 0; i < PROPOSAL_MAX; i++)
- sprop[i] = xstrdup(myproposal[i]);
- server_kexinit = kex_init(sprop);
- packet_start(SSH2_MSG_KEXINIT);
- packet_put_raw(buffer_ptr(server_kexinit), buffer_len(server_kexinit));
+ xfree(cprop[i]);
+
+ switch (kex->kex_type) {
+ case DH_GRP1_SHA1:
+ ssh_dh1_server(kex, client_kexinit, server_kexinit);
+ break;
+ case DH_GEX_SHA1:
+ ssh_dhgex_server(kex, client_kexinit, server_kexinit);
+ break;
+ default:
+ fatal("Unsupported key exchange %d", kex->kex_type);
+ }
+
+ debug("send SSH2_MSG_NEWKEYS.");
+ packet_start(SSH2_MSG_NEWKEYS);
packet_send();
packet_write_wait();
+ debug("done: send SSH2_MSG_NEWKEYS.");
- debug("done");
+ debug("Wait SSH2_MSG_NEWKEYS.");
+ packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
+ debug("GOT SSH2_MSG_NEWKEYS.");
- packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
+#ifdef DEBUG_KEXDH
+ /* send 1st encrypted/maced/compressed message */
+ packet_start(SSH2_MSG_IGNORE);
+ packet_put_cstring("markus");
+ packet_send();
+ packet_write_wait();
+#endif
- /*
- * save raw KEXINIT payload in buffer. this is used during
- * computation of the session_id and the session keys.
- */
- client_kexinit = xmalloc(sizeof(*client_kexinit));
- buffer_init(client_kexinit);
- ptr = packet_get_raw(&payload_len);
- buffer_append(client_kexinit, ptr, payload_len);
+ debug("done: KEX2.");
+}
- /* skip cookie */
- for (i = 0; i < 16; i++)
- (void) packet_get_char();
- /* save kex init proposal strings */
- for (i = 0; i < PROPOSAL_MAX; i++) {
- cprop[i] = packet_get_string(NULL);
- debug("got kexinit string: %s", cprop[i]);
- }
+/*
+ * SSH2 key exchange
+ */
- i = (int) packet_get_char();
- debug("first kex follow == %d", i);
- i = packet_get_int();
- debug("reserved == %d", i);
+/* diffie-hellman-group1-sha1 */
- debug("done read kexinit");
- kex = kex_choose_conf(cprop, sprop, 1);
+void
+ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
+{
+#ifdef DEBUG_KEXDH
+ int i;
+#endif
+ int payload_len, dlen;
+ int slen;
+ unsigned char *signature = NULL;
+ unsigned char *server_host_key_blob = NULL;
+ unsigned int sbloblen;
+ unsigned int klen, kout;
+ unsigned char *kbuf;
+ unsigned char *hash;
+ BIGNUM *shared_secret = 0;
+ DH *dh;
+ BIGNUM *dh_client_pub = 0;
/* KEXDH */
-
debug("Wait SSH2_MSG_KEXDH_INIT.");
packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
#ifdef DEBUG_KEXDH
fprintf(stderr, "\ndh_client_pub= ");
- bignum_print(dh_client_pub);
+ BN_print_fp(stderr, dh_client_pub);
fprintf(stderr, "\n");
debug("bits %d", BN_num_bits(dh_client_pub));
#endif
#ifdef DEBUG_KEXDH
fprintf(stderr, "\np= ");
- bignum_print(dh->p);
+ BN_print_fp(stderr, dh->p);
fprintf(stderr, "\ng= ");
- bignum_print(dh->g);
+ bn_print(dh->g);
fprintf(stderr, "\npub= ");
- bignum_print(dh->pub_key);
+ BN_print_fp(stderr, dh->pub_key);
fprintf(stderr, "\n");
+ DHparams_print_fp(stderr, dh);
#endif
if (!dh_pub_is_valid(dh, dh_client_pub))
packet_disconnect("bad client public DH value");
memset(kbuf, 0, klen);
xfree(kbuf);
- server_host_key = dsa_get_serverkey(options.dsa_key_file);
- dsa_make_serverkey_blob(server_host_key, &server_host_key_blob, &sbloblen);
+ /* XXX precompute? */
+ dsa_make_key_blob(sensitive_data.dsa_host_key,
+ &server_host_key_blob, &sbloblen);
/* calc H */ /* XXX depends on 'kex' */
hash = kex_hash(
fprintf(stderr, "%02x", (hash[i])&0xff);
fprintf(stderr, "\n");
#endif
+ /* save session id := H */
+ /* XXX hashlen depends on KEX */
+ session_id2_len = 20;
+ session_id2 = xmalloc(session_id2_len);
+ memcpy(session_id2, hash, session_id2_len);
+
/* sign H */
- dsa_sign(server_host_key, &signature, &slen, hash, 20);
- /* hashlen depends on KEX */
- key_free(server_host_key);
+ /* XXX hashlen depends on KEX */
+ dsa_sign(sensitive_data.dsa_host_key, &signature, &slen, hash, 20);
+
+ destroy_sensitive_data();
/* send server hostkey, DH pubkey 'f' and singed H */
packet_start(SSH2_MSG_KEXDH_REPLY);
packet_put_string((char *)server_host_key_blob, sbloblen);
- packet_put_bignum2(dh->pub_key); // f
+ packet_put_bignum2(dh->pub_key); /* f */
packet_put_string((char *)signature, slen);
packet_send();
+ xfree(signature);
+ xfree(server_host_key_blob);
packet_write_wait();
kex_derive_keys(kex, hash, shared_secret);
/* have keys, free DH */
DH_free(dh);
+}
- debug("send SSH2_MSG_NEWKEYS.");
- packet_start(SSH2_MSG_NEWKEYS);
+/* diffie-hellman-group-exchange-sha1 */
+
+void
+ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
+{
+#ifdef DEBUG_KEXDH
+ int i;
+#endif
+ int payload_len, dlen;
+ int slen, nbits;
+ unsigned char *signature = NULL;
+ unsigned char *server_host_key_blob = NULL;
+ unsigned int sbloblen;
+ unsigned int klen, kout;
+ unsigned char *kbuf;
+ unsigned char *hash;
+ BIGNUM *shared_secret = 0;
+ DH *dh;
+ BIGNUM *dh_client_pub = 0;
+
+/* KEXDHGEX */
+ debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST.");
+ packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_REQUEST);
+ nbits = packet_get_int();
+ dh = choose_dh(nbits);
+
+ debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP.");
+ packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
+ packet_put_bignum2(dh->p);
+ packet_put_bignum2(dh->g);
packet_send();
packet_write_wait();
- debug("done: send SSH2_MSG_NEWKEYS.");
- debug("Wait SSH2_MSG_NEWKEYS.");
- packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
- debug("GOT SSH2_MSG_NEWKEYS.");
+ debug("Wait SSH2_MSG_KEX_DH_GEX_INIT.");
+ packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT);
+
+ /* key, cert */
+ dh_client_pub = BN_new();
+ if (dh_client_pub == NULL)
+ fatal("dh_client_pub == NULL");
+ packet_get_bignum2(dh_client_pub, &dlen);
#ifdef DEBUG_KEXDH
- /* send 1st encrypted/maced/compressed message */
- packet_start(SSH2_MSG_IGNORE);
- packet_put_cstring("markus");
+ fprintf(stderr, "\ndh_client_pub= ");
+ BN_print_fp(stderr, dh_client_pub);
+ fprintf(stderr, "\n");
+ debug("bits %d", BN_num_bits(dh_client_pub));
+#endif
+
+#ifdef DEBUG_KEXDH
+ fprintf(stderr, "\np= ");
+ BN_print_fp(stderr, dh->p);
+ fprintf(stderr, "\ng= ");
+ bn_print(dh->g);
+ fprintf(stderr, "\npub= ");
+ BN_print_fp(stderr, dh->pub_key);
+ fprintf(stderr, "\n");
+ DHparams_print_fp(stderr, dh);
+#endif
+ if (!dh_pub_is_valid(dh, dh_client_pub))
+ packet_disconnect("bad client public DH value");
+
+ klen = DH_size(dh);
+ kbuf = xmalloc(klen);
+ kout = DH_compute_key(kbuf, dh_client_pub, dh);
+
+#ifdef DEBUG_KEXDH
+ debug("shared secret: len %d/%d", klen, kout);
+ fprintf(stderr, "shared secret == ");
+ for (i = 0; i< kout; i++)
+ fprintf(stderr, "%02x", (kbuf[i])&0xff);
+ fprintf(stderr, "\n");
+#endif
+ shared_secret = BN_new();
+
+ BN_bin2bn(kbuf, kout, shared_secret);
+ memset(kbuf, 0, klen);
+ xfree(kbuf);
+
+ /* XXX precompute? */
+ dsa_make_key_blob(sensitive_data.dsa_host_key,
+ &server_host_key_blob, &sbloblen);
+
+ /* calc H */ /* XXX depends on 'kex' */
+ hash = kex_hash_gex(
+ client_version_string,
+ server_version_string,
+ buffer_ptr(client_kexinit), buffer_len(client_kexinit),
+ buffer_ptr(server_kexinit), buffer_len(server_kexinit),
+ (char *)server_host_key_blob, sbloblen,
+ nbits, dh->p, dh->g,
+ dh_client_pub,
+ dh->pub_key,
+ shared_secret
+ );
+ buffer_free(client_kexinit);
+ buffer_free(server_kexinit);
+ xfree(client_kexinit);
+ xfree(server_kexinit);
+#ifdef DEBUG_KEXDH
+ fprintf(stderr, "hash == ");
+ for (i = 0; i< 20; i++)
+ fprintf(stderr, "%02x", (hash[i])&0xff);
+ fprintf(stderr, "\n");
+#endif
+ /* save session id := H */
+ /* XXX hashlen depends on KEX */
+ session_id2_len = 20;
+ session_id2 = xmalloc(session_id2_len);
+ memcpy(session_id2, hash, session_id2_len);
+
+ /* sign H */
+ /* XXX hashlen depends on KEX */
+ dsa_sign(sensitive_data.dsa_host_key, &signature, &slen, hash, 20);
+
+ destroy_sensitive_data();
+
+ /* send server hostkey, DH pubkey 'f' and singed H */
+ packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
+ packet_put_string((char *)server_host_key_blob, sbloblen);
+ packet_put_bignum2(dh->pub_key); /* f */
+ packet_put_string((char *)signature, slen);
packet_send();
+ xfree(signature);
+ xfree(server_host_key_blob);
packet_write_wait();
-#endif
- debug("done: KEX2.");
+
+ kex_derive_keys(kex, hash, shared_secret);
+ packet_set_kex(kex);
+
+ /* have keys, free DH */
+ DH_free(dh);
}
+