* 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 1.117 2000/05/18 13:27:36 djm Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.179 2001/03/26 08:07:09 markus Exp $");
+#include <openssl/dh.h>
+#include <openssl/bn.h>
+#include <openssl/hmac.h>
+
+#include "ssh.h"
+#include "ssh1.h"
+#include "ssh2.h"
#include "xmalloc.h"
#include "rsa.h"
-#include "ssh.h"
-#include "pty.h"
+#include "sshpty.h"
#include "packet.h"
-#include "cipher.h"
#include "mpaux.h"
+#include "log.h"
#include "servconf.h"
#include "uidswap.h"
#include "compat.h"
#include "buffer.h"
-
-#include "ssh2.h"
-#include <openssl/dh.h>
-#include <openssl/bn.h>
-#include <openssl/hmac.h>
+#include "cipher.h"
#include "kex.h"
-#include <openssl/dsa.h>
-#include <openssl/rsa.h>
#include "key.h"
-#include "dsa.h"
-
-#include "auth.h"
+#include "dh.h"
#include "myproposal.h"
#include "authfile.h"
+#include "pathnames.h"
+#include "atomicio.h"
+#include "canohost.h"
+#include "auth.h"
+#include "misc.h"
#ifdef LIBWRAP
#include <tcpd.h>
#define O_NOCTTY 0
#endif
+#ifdef HAVE___PROGNAME
+extern char *__progname;
+#else
+char *__progname;
+#endif
+
/* Server configuration options. */
ServerOptions options;
/* Name of the server configuration file. */
-char *config_file_name = SERVER_CONFIG_FILE;
+char *config_file_name = _PATH_SERVER_CONFIG_FILE;
/*
* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
/* Flag indicating that the daemon is being started from inetd. */
int inetd_flag = 0;
+/* Flag indicating that sshd should not detach and become a daemon. */
+int no_daemon_flag = 0;
+
/* debug goes to stderr unless inetd_flag is set */
int log_stderr = 0;
-/* argv[0] without path. */
-char *av0;
-
/* 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 empheral server key. */
- RSA *host_key; /* Private part of host key. */
- Key *dsa_host_key; /* Private DSA host key. */
+ Key *server_key; /* ephemeral server key */
+ Key *ssh1_host_key; /* ssh1 host key */
+ Key **host_keys; /* all private host keys */
+ int have_ssh1_key;
+ int have_ssh2_key;
+ u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
} sensitive_data;
/*
- * Flag indicating whether the current session key has been used. This flag
- * is set whenever the key is used, and cleared when the key is regenerated.
+ * 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_used = 0;
+int key_do_regen = 0;
/* This is set to true when SIGHUP is received. */
int received_sighup = 0;
-/* Public side of the server key. This value is regenerated regularly with
- the private key. */
-RSA *public_key;
-
/* session identifier, used by RSA-auth */
-unsigned char session_id[16];
+u_char session_id[16];
/* same for ssh2 */
-unsigned char *session_id2 = NULL;
+u_char *session_id2 = NULL;
int session_id2_len = 0;
+/* record remote hostname or ip */
+u_int utmp_len = MAXHOSTNAMELEN;
+
/* Prototypes for various functions defined later in this file. */
-void do_ssh1_kex();
-void do_ssh2_kex();
+void do_ssh1_kex(void);
+void do_ssh2_kex(void);
+
+void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *);
+void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *);
/*
* Close all listening sockets
* Restarts the server.
*/
void
-sighup_restart()
+sighup_restart(void)
{
log("Received SIGHUP; restarting.");
close_listen_socks();
execv(saved_argv[0], saved_argv);
- log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
+ log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno));
exit(1);
}
* 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)
+generate_ephemeral_server_key(void)
{
- int save_errno = errno;
-
- /* Check if we should generate a new key. */
- if (key_used) {
- /* This should really be done in the background. */
- log("Generating new %d bit RSA key.", options.server_key_bits);
-
- if (sensitive_data.private_key != NULL)
- RSA_free(sensitive_data.private_key);
- sensitive_data.private_key = RSA_new();
+ u_int32_t rand = 0;
+ int i;
- if (public_key != NULL)
- RSA_free(public_key);
- public_key = RSA_new();
+ log("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "",
+ options.server_key_bits);
+ if (sensitive_data.server_key != NULL)
+ key_free(sensitive_data.server_key);
+ sensitive_data.server_key = key_generate(KEY_RSA1, options.server_key_bits);
+ log("RSA key generation complete.");
- rsa_generate_key(sensitive_data.private_key, public_key,
- options.server_key_bits);
- arc4random_stir();
- key_used = 0;
- log("RSA key generation complete.");
+ for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
+ if (i % 4 == 0)
+ rand = arc4random();
+ sensitive_data.ssh1_cookie[i] = rand & 0xff;
+ rand >>= 8;
}
- /* Reschedule the alarm. */
- signal(SIGALRM, key_regeneration_alarm);
- alarm(options.key_regeneration_time);
+ arc4random_stir();
+}
+
+void
+key_regeneration_alarm(int sig)
+{
+ int save_errno = errno;
+ signal(SIGALRM, SIG_DFL);
errno = save_errno;
+ key_do_regen = 1;
}
void
fatal_cleanup();
}
- /* Read other side\'s version identification. */
+ /* Read other side's version identification. */
+ memset(buf, 0, sizeof(buf));
for (i = 0; i < sizeof(buf) - 1; i++) {
- if (read(sock_in, &buf[i], 1) != 1) {
- log("Did not receive ident string from %s.", get_remote_ipaddr());
+ 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] = '\n';
- buf[i + 1] = 0;
+ 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] == '\n' */
- buf[i + 1] = 0;
+ buf[i] = 0;
break;
}
}
compat_datafellows(remote_version);
+ if (datafellows & SSH_BUG_SCANNER) {
+ log("scanned from %s with %s. Don't panic.",
+ get_remote_ipaddr(), client_version_string);
+ fatal_cleanup();
+ }
+
mismatch = 0;
switch(remote_major) {
case 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 */
break;
}
chop(server_version_string);
- chop(client_version_string);
debug("Local version string %.200s", server_version_string);
if (mismatch) {
}
+/* Destroy the host and server keys. They will no longer be needed. */
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);
+ int i;
+
+ if (sensitive_data.server_key) {
+ key_free(sensitive_data.server_key);
+ sensitive_data.server_key = NULL;
+ }
+ 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;
+ }
+ }
+ sensitive_data.ssh1_host_key = NULL;
+ memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
+}
+
+char *
+list_hostkey_types(void)
+{
+ static char buf[1024];
+ int i;
+ buf[0] = '\0';
+ for(i = 0; i < options.num_host_key_files; i++) {
+ Key *key = sensitive_data.host_keys[i];
+ if (key == NULL)
+ continue;
+ switch(key->type) {
+ case KEY_RSA:
+ case KEY_DSA:
+ strlcat(buf, key_ssh_name(key), sizeof buf);
+ strlcat(buf, ",", sizeof buf);
+ break;
+ }
+ }
+ i = strlen(buf);
+ if (i > 0 && buf[i-1] == ',')
+ buf[i-1] = '\0';
+ debug("list_hostkey_types: %s", buf);
+ return buf;
+}
+
+Key *
+get_hostkey_by_type(int type)
+{
+ int i;
+ for(i = 0; i < options.num_host_key_files; i++) {
+ Key *key = sensitive_data.host_keys[i];
+ if (key != NULL && key->type == type)
+ return key;
+ }
+ return NULL;
+}
+
+/*
+ * 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, on = 1;
+ int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
pid_t pid;
socklen_t fromlen;
- int silent = 0;
fd_set *fdset;
struct sockaddr_storage from;
const char *remote_ip;
struct addrinfo *ai;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
int listen_sock, maxfd;
+ int startup_p[2];
+ int startups = 0;
+ Key *key;
+ int ret, key_used = 0;
+
+ __progname = get_progname(av[0]);
+ init_rng();
- /* Save argv[0]. */
+ /* Save argv. */
+ saved_argc = ac;
saved_argv = av;
- if (strchr(av[0], '/'))
- av0 = strrchr(av[0], '/') + 1;
- else
- av0 = av[0];
/* 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:diqQ46")) != EOF) {
+ while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != -1) {
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 'D':
+ no_daemon_flag = 1;
break;
case 'i':
inetd_flag = 1;
break;
case 'Q':
- silent = 1;
+ /* ignored */
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':
options.key_regeneration_time = atoi(optarg);
break;
case 'h':
- options.host_key_file = optarg;
+ if (options.num_host_key_files >= MAX_HOSTKEYS) {
+ fprintf(stderr, "too many host keys.\n");
+ exit(1);
+ }
+ options.host_key_files[options.num_host_key_files++] = optarg;
break;
case 'V':
client_version_string = optarg;
/* only makes sense with inetd_flag, i.e. no listen() */
inetd_flag = 1;
break;
+ case '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, "Usage: %s [options]\n", __progname);
fprintf(stderr, "Options:\n");
- fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
- fprintf(stderr, " -d Debugging mode\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, " -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: 300)\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",
- HOST_KEY_FILE);
+ _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);
* Force logging to stderr until we have loaded the private host
* key (unless started from inetd)
*/
- log_init(av0,
+ log_init(__progname,
options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
- !silent && !inetd_flag);
+ !inetd_flag);
+
+ seed_rng();
/* Read server configuration options from the configuration file. */
read_server_config(&options, config_file_name);
debug("sshd version %.100s", SSH_VERSION);
- 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)) {
+ /* 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[i] = NULL;
+ sensitive_data.server_key = NULL;
+ sensitive_data.ssh1_host_key = NULL;
+ sensitive_data.have_ssh1_key = 0;
+ sensitive_data.have_ssh2_key = 0;
+
+ for(i = 0; i < options.num_host_key_files; i++) {
+ key = key_load_private(options.host_key_files[i], "", NULL);
+ sensitive_data.host_keys[i] = key;
+ if (key == 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;
+ options.host_key_files[i], strerror(errno));
+ sensitive_data.host_keys[i] = NULL;
+ continue;
}
- 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;
+ switch(key->type){
+ case KEY_RSA1:
+ sensitive_data.ssh1_host_key = key;
+ sensitive_data.have_ssh1_key = 1;
+ break;
+ case KEY_RSA:
+ case KEY_DSA:
+ sensitive_data.have_ssh2_key = 1;
+ break;
}
+ debug("private host key: #%d type %d %s", i, key->type,
+ key_type(key));
+ }
+ if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
+ log("Disabling protocol version 1. Could not load host key");
+ options.protocol &= ~SSH_PROTO_1;
}
- 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");
+ if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
+ log("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.");
exit(1);
}
* 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 &&
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED &&
options.server_key_bits <
- BN_num_bits(sensitive_data.host_key->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.host_key->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);
}
}
+#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);
+ log_init(__progname, 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 (!debug_flag && !inetd_flag) {
+ if (!(debug_flag || inetd_flag || no_daemon_flag)) {
#ifdef TIOCNOTTY
int fd;
#endif /* TIOCNOTTY */
/* Disconnect from the controlling tty. */
#ifdef TIOCNOTTY
- fd = open("/dev/tty", O_RDWR | O_NOCTTY);
+ fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
if (fd >= 0) {
(void) ioctl(fd, TIOCNOTTY, NULL);
close(fd);
#endif /* TIOCNOTTY */
}
/* Reinitialize the log (because of the fork above). */
- log_init(av0, options.log_level, options.log_facility, log_stderr);
-
- /* Do not display messages to stdout in RSA code. */
- rsa_set_verbose(0);
+ log_init(__progname, options.log_level, options.log_facility, log_stderr);
/* Initialize the random number generator. */
arc4random_stir();
/* 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) {
s2 = dup(s1);
sock_in = dup(0);
sock_out = dup(1);
+ startup_pipe = -1;
/*
* We intentionally do not close the descriptors 0, 1, and 2
* as our code for setting the descriptors won\'t work if
* ttyfd happens to be one of those.
*/
debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
-
- if (options.protocol & SSH_PROTO_1) {
- 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.");
- }
+ if (options.protocol & SSH_PROTO_1)
+ generate_ephemeral_server_key();
} else {
for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
debug("Bind to port %s on %s.", strport, ntop);
/* Bind the socket to the desired port. */
- if ((bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) &&
- (!ai->ai_next)) {
- error("Bind to port %s on %s failed: %.200s.",
- strport, ntop, strerror(errno));
+ if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
+ if (!ai->ai_next)
+ error("Bind to port %s on %s failed: %.200s.",
+ strport, ntop, strerror(errno));
close(listen_sock);
continue;
}
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
+ * Record our pid in /var/run/sshd.pid to make it
+ * easier to kill the correct sshd. We don't want to
+ * do this before the bind above because the bind will
* fail if there already is a daemon, and this will
* overwrite any old pid in the file.
*/
- f = fopen(options.pid_file, "w");
+ f = fopen(options.pid_file, "wb");
if (f) {
- fprintf(f, "%u\n", (unsigned int) getpid());
+ fprintf(f, "%u\n", (u_int) getpid());
fclose(f);
}
}
- 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.");
-
- /* Schedule server key regeneration alarm. */
- signal(SIGALRM, key_regeneration_alarm);
- alarm(options.key_regeneration_time);
- }
+ if (options.protocol & SSH_PROTO_1)
+ generate_ephemeral_server_key();
/* Arrange to restart on SIGHUP. The handler needs listen_sock. */
signal(SIGHUP, sighup_handler);
+
signal(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+1, NFDBITS) * sizeof(fd_mask);
+ fdset = (fd_set *)xmalloc(fdsetsz);
memset(fdset, 0, fdsetsz);
+
for (i = 0; i < num_listen_socks; i++)
FD_SET(listen_socks[i], fdset);
- 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_SET(startup_pipes[i], fdset);
+
+ /* Wait in select until there is a connection. */
+ ret = select(maxfd+1, fdset, NULL, NULL, NULL);
+ if (ret < 0 && errno != EINTR)
+ error("select: %.100s", strerror(errno));
+ if (key_used && key_do_regen) {
+ generate_ephemeral_server_key();
+ key_used = 0;
+ key_do_regen = 0;
}
+ if (ret < 0)
+ continue;
+
+ for (i = 0; i < options.max_startups; i++)
+ if (startup_pipes[i] != -1 &&
+ FD_ISSET(startup_pipes[i], fdset)) {
+ /*
+ * the read end of the pipe is ready
+ * if the child has closed the pipe
+ * after successful authentication
+ * or if the child has died
+ */
+ close(startup_pipes[i]);
+ startup_pipes[i] = -1;
+ startups--;
+ }
for (i = 0; i < num_listen_socks; i++) {
if (!FD_ISSET(listen_socks[i], fdset))
continue;
- fromlen = sizeof(from);
- newsock = accept(listen_socks[i], (struct sockaddr *)&from,
- &fromlen);
- if (newsock < 0) {
- if (errno != EINTR && errno != EWOULDBLOCK)
- error("accept: %.100s", strerror(errno));
- continue;
- }
- if (fcntl(newsock, F_SETFL, 0) < 0) {
- error("newsock del O_NONBLOCK: %s", strerror(errno));
- 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(__progname, options.log_level, options.log_facility, log_stderr);
+ break;
+ }
}
- }
-
- /* Parent. Stay in the loop. */
- if (pid < 0)
- error("fork: %.100s", strerror(errno));
- else
- debug("Forked child %d.", pid);
- /* Mark that the key has been used (it was "given" to the child). */
- key_used = 1;
+ /* Parent. Stay in the loop. */
+ if (pid < 0)
+ error("fork: %.100s", strerror(errno));
+ else
+ debug("Forked child %d.", pid);
+
+ close(startup_p[1]);
+
+ /* Mark that the key has been used (it was "given" to the child). */
+ if ((options.protocol & SSH_PROTO_1) &&
+ key_used == 0) {
+ /* Schedule server key regeneration alarm. */
+ signal(SIGALRM, key_regeneration_alarm);
+ alarm(options.key_regeneration_time);
+ key_used = 1;
+ }
- arc4random_stir();
+ arc4random_stir();
- /* Close the new socket (the child is now taking care of it). */
- close(newsock);
- } /* for (i = 0; i < num_listen_socks; i++) */
+ /* 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
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.
{
struct request_info req;
- request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
+ request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL);
fromhost(&req);
if (!hosts_access(&req)) {
sshd_exchange_identification(sock_in, sock_out);
/*
- * Check that the connection comes from a privileged port. Rhosts-
- * and Rhosts-RSA-Authentication only make sense from priviledged
+ * 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 not trusted.");
options.rhosts_authentication = 0;
- options.rhosts_rsa_authentication = 0;
}
#ifdef KRB4
if (!packet_connection_is_ipv4() &&
options.kerberos_authentication = 0;
}
#endif /* KRB4 */
+#ifdef AFS
+ /* If machine has AFS, set process authentication group. */
+ if (k_hasafs()) {
+ k_setpag();
+ k_unlog();
+ }
+#endif /* AFS */
packet_set_nonblocking();
* SSH1 key exchange
*/
void
-do_ssh1_kex()
+do_ssh1_kex(void)
{
int i, len;
int plen, slen;
+ int rsafail = 0;
BIGNUM *session_key_int;
- unsigned char session_key[SSH_SESSION_KEY_LENGTH];
- unsigned char cookie[8];
- unsigned int cipher_type, auth_mask, protocol_flags;
+ 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;
/*
packet_put_char(cookie[i]);
/* Store our public server RSA key. */
- packet_put_int(BN_num_bits(public_key->n));
- packet_put_bignum(public_key->e);
- packet_put_bignum(public_key->n);
+ packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
+ packet_put_bignum(sensitive_data.server_key->rsa->e);
+ packet_put_bignum(sensitive_data.server_key->rsa->n);
/* Store our public host RSA key. */
- packet_put_int(BN_num_bits(sensitive_data.host_key->n));
- packet_put_bignum(sensitive_data.host_key->e);
- packet_put_bignum(sensitive_data.host_key->n);
+ packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
+ packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
+ packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
/* Put protocol flags. */
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;
if (options.afs_token_passing)
auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
#endif
-#ifdef SKEY
- if (options.skey_authentication == 1)
+ if (options.challenge_reponse_authentication == 1)
auth_mask |= 1 << SSH_AUTH_TIS;
-#endif
if (options.password_authentication)
auth_mask |= 1 << SSH_AUTH_PASSWORD;
packet_put_int(auth_mask);
packet_send();
packet_write_wait();
- debug("Sent %d bit public key and %d bit host key.",
- BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
+ debug("Sent %d bit server key and %d bit host key.",
+ BN_num_bits(sensitive_data.server_key->rsa->n),
+ 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);
/* 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
* Decrypt it using our private server key and private host key (key
* with larger modulus first).
*/
- if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
- /* Private key has bigger modulus. */
- if (BN_num_bits(sensitive_data.private_key->n) <
- BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
- fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
- get_remote_ipaddr(),
- BN_num_bits(sensitive_data.private_key->n),
- BN_num_bits(sensitive_data.host_key->n),
- SSH_KEY_BITS_RESERVED);
+ 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);
}
- rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.private_key);
- rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.host_key);
+ 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.host_key->n) <
- BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
- fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
- get_remote_ipaddr(),
- BN_num_bits(sensitive_data.host_key->n),
- BN_num_bits(sensitive_data.private_key->n),
- SSH_KEY_BITS_RESERVED);
+ 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);
}
- rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.host_key);
- rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.private_key);
+ 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++;
}
-
- compute_session_id(session_id, cookie,
- sensitive_data.host_key->n,
- sensitive_data.private_key->n);
-
- /* Destroy the private and public keys. They will no longer be needed. */
- destroy_sensitive_data();
-
/*
* Extract session key from the decrypted integer. The key is in the
* least significant 256 bits of the integer; the first byte of the
* key is in the highest bits.
*/
- BN_mask_bits(session_key_int, sizeof(session_key) * 8);
- len = BN_num_bytes(session_key_int);
- 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));
- memset(session_key, 0, sizeof(session_key));
- BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
+ 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)) {
+ 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));
+ rsafail++;
+ } else {
+ memset(session_key, 0, sizeof(session_key));
+ BN_bn2bin(session_key_int,
+ session_key + sizeof(session_key) - len);
+
+ compute_session_id(session_id, cookie,
+ sensitive_data.ssh1_host_key->rsa->n,
+ sensitive_data.server_key->rsa->n);
+ /*
+ * Xor the first 16 bytes of the session key with the
+ * session id.
+ */
+ for (i = 0; i < 16; i++)
+ session_key[i] ^= session_id[i];
+ }
+ }
+ if (rsafail) {
+ int bytes = BN_num_bytes(session_key_int);
+ char *buf = xmalloc(bytes);
+ MD5_CTX md;
+
+ log("do_connection: generating a fake encryption key");
+ BN_bn2bin(session_key_int, buf);
+ MD5_Init(&md);
+ MD5_Update(&md, buf, bytes);
+ MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
+ MD5_Final(session_key, &md);
+ MD5_Init(&md);
+ MD5_Update(&md, session_key, 16);
+ MD5_Update(&md, buf, bytes);
+ MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
+ MD5_Final(session_key + 16, &md);
+ memset(buf, 0, bytes);
+ xfree(buf);
+ 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_sensitive_data();
/* Destroy the decrypted integer. It is no longer needed. */
BN_clear_free(session_key_int);
- /* Xor the first 16 bytes of the session key with the session id. */
- for (i = 0; i < 16; i++)
- session_key[i] ^= session_id[i];
-
/* Set the session key. From this on all communications will be encrypted. */
packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
* SSH2 key exchange: diffie-hellman-group1-sha1
*/
void
-do_ssh2_kex()
+do_ssh2_kex(void)
{
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;
char *cprop[PROPOSAL_MAX];
- char *sprop[PROPOSAL_MAX];
/* KEXINIT */
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
}
+ if (options.macs != NULL) {
+ myproposal[PROPOSAL_MAC_ALGS_CTOS] =
+ myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
+ }
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
- debug("Sending KEX init.");
+ myproposal[PROPOSAL_ENC_ALGS_STOC] =
+ compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
+ server_kexinit = kex_init(myproposal);
+ client_kexinit = xmalloc(sizeof(*client_kexinit));
+ buffer_init(client_kexinit);
+
+ /* 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("Wait SSH2_MSG_NEWKEYS.");
+ packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
+ debug("GOT SSH2_MSG_NEWKEYS.");
+
+#ifdef DEBUG_KEXDH
+ /* send 1st encrypted/maced/compressed message */
+ packet_start(SSH2_MSG_IGNORE);
+ packet_put_cstring("markus");
packet_send();
packet_write_wait();
+#endif
- debug("done");
+ debug("done: KEX2.");
+}
- packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
+/*
+ * SSH2 key exchange
+ */
- /*
- * 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);
-
- /* 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]);
- }
+/* diffie-hellman-group1-sha1 */
- i = (int) packet_get_char();
- debug("first kex follow == %d", i);
- i = packet_get_int();
- debug("reserved == %d", i);
+void
+ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
+{
+#ifdef DEBUG_KEXDH
+ int i;
+#endif
+ int payload_len, dlen;
+ int slen;
+ u_char *signature = NULL;
+ u_char *server_host_key_blob = NULL;
+ u_int sbloblen;
+ u_int klen, kout;
+ u_char *kbuf;
+ u_char *hash;
+ BIGNUM *shared_secret = 0;
+ DH *dh;
+ BIGNUM *dh_client_pub = 0;
+ Key *hostkey;
- debug("done read kexinit");
- kex = kex_choose_conf(cprop, sprop, 1);
+ hostkey = get_hostkey_by_type(kex->hostkey_type);
+ if (hostkey == NULL)
+ fatal("Unsupported hostkey type %d", kex->hostkey_type);
/* KEXDH */
+ /* generate DH key */
+ dh = dh_new_group1(); /* XXX depends on 'kex' */
+ dh_gen_key(dh, kex->we_need * 8);
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
- /* generate DH key */
- dh = dh_new_group1(); /* XXX depends on 'kex' */
-
#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");
xfree(kbuf);
/* XXX precompute? */
- dsa_make_key_blob(sensitive_data.dsa_host_key, &server_host_key_blob, &sbloblen);
+ key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
/* calc H */ /* XXX depends on 'kex' */
hash = kex_hash(
buffer_free(server_kexinit);
xfree(client_kexinit);
xfree(server_kexinit);
+ BN_free(dh_client_pub);
#ifdef DEBUG_KEXDH
fprintf(stderr, "hash == ");
for (i = 0; i< 20; i++)
/* sign H */
/* XXX hashlen depends on KEX */
- dsa_sign(sensitive_data.dsa_host_key, &signature, &slen, hash, 20);
+ key_sign(hostkey, &signature, &slen, hash, 20);
destroy_sensitive_data();
packet_write_wait();
kex_derive_keys(kex, hash, shared_secret);
+ BN_clear_free(shared_secret);
packet_set_kex(kex);
/* 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;
+ u_char *signature = NULL;
+ u_char *server_host_key_blob = NULL;
+ u_int sbloblen;
+ u_int klen, kout;
+ u_char *kbuf;
+ u_char *hash;
+ BIGNUM *shared_secret = 0;
+ DH *dh;
+ BIGNUM *dh_client_pub = 0;
+ Key *hostkey;
+
+ hostkey = get_hostkey_by_type(kex->hostkey_type);
+ if (hostkey == NULL)
+ fatal("Unsupported hostkey type %d", kex->hostkey_type);
+
+/* 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.");
+ /* Compute our exchange value in parallel with the client */
+
+ dh_gen_key(dh, kex->we_need * 8);
+
+ 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? */
+ key_to_blob(hostkey, &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);
+ BN_free(dh_client_pub);
+#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 */
+ key_sign(hostkey, &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);
+ BN_clear_free(shared_secret);
+ packet_set_kex(kex);
+
+ /* have keys, free DH */
+ DH_free(dh);
}
andersk / openssh.git / blobdiff