* called by a name other than "ssh" or "Secure Shell".
*
* SSH2 implementation:
+ * Privilege Separation:
*
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
+ * Copyright (c) 2002 Niels Provos. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
*/
#include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.166 2001/02/11 12:59:25 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.238 2002/03/23 20:57:26 stevesk Exp $");
#include <openssl/dh.h>
#include <openssl/bn.h>
-#include <openssl/hmac.h>
+#include <openssl/md5.h>
+#include <openssl/rand.h>
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "rsa.h"
-#include "pty.h"
+#include "sshpty.h"
#include "packet.h"
#include "mpaux.h"
#include "log.h"
#include "canohost.h"
#include "auth.h"
#include "misc.h"
+#include "dispatch.h"
+#include "channels.h"
+#include "session.h"
+#include "monitor_mm.h"
+#include "monitor.h"
+#include "monitor_wrap.h"
+#include "monitor_fdpass.h"
#ifdef LIBWRAP
#include <tcpd.h>
*/
int debug_flag = 0;
+/* Flag indicating that the daemon should only test the configuration and keys. */
+int test_flag = 0;
+
/* Flag indicating that the daemon is being started from inetd. */
int inetd_flag = 0;
char *client_version_string = NULL;
char *server_version_string = NULL;
+/* for rekeying XXX fixme */
+Kex *xxx_kex;
+
/*
* Any really sensitive data in the application is contained in this
* structure. The idea is that this structure could be locked into memory so
* not very useful. Currently, memory locking is not implemented.
*/
struct {
- Key *server_key; /* empheral server 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 RSA server key needs to be regenerated.
* Is set in the SIGALRM handler and cleared when the key is regenerated.
*/
-int key_do_regen = 0;
+static volatile sig_atomic_t key_do_regen = 0;
-/* This is set to true when SIGHUP is received. */
-int received_sighup = 0;
+/* This is set to true when a signal is received. */
+static volatile sig_atomic_t received_sighup = 0;
+static volatile sig_atomic_t received_sigterm = 0;
/* session identifier, used by RSA-auth */
u_char session_id[16];
/* record remote hostname or ip */
u_int utmp_len = MAXHOSTNAMELEN;
+/* options.max_startup sized array of fd ints */
+int *startup_pipes = NULL;
+int startup_pipe; /* in child */
+
+/* variables used for privilege separation */
+extern struct monitor *monitor;
+extern int use_privsep;
+
/* Prototypes for various functions defined later in this file. */
-void do_ssh1_kex(void);
-void do_ssh2_kex(void);
+void destroy_sensitive_data(void);
+void demote_sensitive_data(void);
-void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *);
-void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *);
+static void do_ssh1_kex(void);
+static void do_ssh2_kex(void);
/*
* Close all listening sockets
*/
-void
+static void
close_listen_socks(void)
{
int i;
num_listen_socks = -1;
}
+static void
+close_startup_pipes(void)
+{
+ int i;
+ if (startup_pipes)
+ for (i = 0; i < options.max_startups; i++)
+ if (startup_pipes[i] != -1)
+ close(startup_pipes[i]);
+}
+
/*
* Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
* the effect is to reread the configuration file (and to regenerate
* the server key).
*/
-void
+static void
sighup_handler(int sig)
{
+ int save_errno = errno;
+
received_sighup = 1;
signal(SIGHUP, sighup_handler);
+ errno = save_errno;
}
/*
* Called from the main program after receiving SIGHUP.
* Restarts the server.
*/
-void
+static void
sighup_restart(void)
{
log("Received SIGHUP; restarting.");
close_listen_socks();
+ close_startup_pipes();
execv(saved_argv[0], saved_argv);
log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno));
exit(1);
/*
* Generic signal handler for terminating signals in the master daemon.
- * These close the listen socket; not closing it seems to cause "Address
- * already in use" problems on some machines, which is inconvenient.
*/
-void
+static void
sigterm_handler(int sig)
{
- log("Received signal %d; terminating.", sig);
- close_listen_socks();
- unlink(options.pid_file);
- exit(255);
+ received_sigterm = sig;
}
/*
* SIGCHLD handler. This is called whenever a child dies. This will then
- * reap any zombies left by exited c.
+ * reap any zombies left by exited children.
*/
-void
+static void
main_sigchld_handler(int sig)
{
int save_errno = errno;
/*
* Signal handler for the alarm after the login grace period has expired.
*/
-void
+static void
grace_alarm_handler(int sig)
{
+ /* XXX no idea how fix this signal handler */
+
/* Close the connection. */
packet_close();
* Thus there should be no concurrency control/asynchronous execution
* problems.
*/
-void
-generate_empheral_server_key(void)
+static void
+generate_ephemeral_server_key(void)
{
- log("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "",
- options.server_key_bits);
+ u_int32_t rand = 0;
+ int i;
+
+ verbose("Generating %s%d bit RSA key.",
+ sensitive_data.server_key ? "new " : "", options.server_key_bits);
if (sensitive_data.server_key != NULL)
key_free(sensitive_data.server_key);
- sensitive_data.server_key = key_generate(KEY_RSA1, options.server_key_bits);
+ sensitive_data.server_key = key_generate(KEY_RSA1,
+ options.server_key_bits);
+ verbose("RSA key generation complete.");
+
+ for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
+ if (i % 4 == 0)
+ rand = arc4random();
+ sensitive_data.ssh1_cookie[i] = rand & 0xff;
+ rand >>= 8;
+ }
arc4random_stir();
- log("RSA key generation complete.");
}
-void
+static void
key_regeneration_alarm(int sig)
{
int save_errno = errno;
key_do_regen = 1;
}
-void
+static void
sshd_exchange_identification(int sock_in, int sock_out)
{
int i, mismatch;
/* Send our protocol version identification. */
if (atomicio(write, sock_out, server_version_string, strlen(server_version_string))
!= strlen(server_version_string)) {
- log("Could not write ident string to %s.", get_remote_ipaddr());
+ log("Could not write ident string to %s", get_remote_ipaddr());
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 (atomicio(read, sock_in, &buf[i], 1) != 1) {
- log("Did not receive ident string from %s.", get_remote_ipaddr());
+ 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)
continue;
}
if (buf[i] == '\n') {
- /* buf[i] == '\n' */
- buf[i + 1] = 0;
+ buf[i] = 0;
break;
}
}
fatal_cleanup();
}
debug("Client protocol version %d.%d; client software version %.100s",
- remote_major, remote_minor, remote_version);
+ remote_major, remote_minor, remote_version);
compat_datafellows(remote_version);
+ if (datafellows & SSH_BUG_SCANNER) {
+ log("scanned from %s with %s. Don't panic.",
+ get_remote_ipaddr(), client_version_string);
+ fatal_cleanup();
+ }
+
mismatch = 0;
- switch(remote_major) {
+ switch (remote_major) {
case 1:
if (remote_minor == 99) {
if (options.protocol & SSH_PROTO_2)
break;
}
chop(server_version_string);
- chop(client_version_string);
debug("Local version string %.200s", server_version_string);
if (mismatch) {
server_version_string, client_version_string);
fatal_cleanup();
}
- if (compat20)
- packet_set_ssh2_format();
}
key_free(sensitive_data.server_key);
sensitive_data.server_key = NULL;
}
- for(i = 0; i < options.num_host_key_files; i++) {
+ for (i = 0; i < options.num_host_key_files; i++) {
if (sensitive_data.host_keys[i]) {
key_free(sensitive_data.host_keys[i]);
sensitive_data.host_keys[i] = NULL;
}
}
sensitive_data.ssh1_host_key = NULL;
+ memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
}
-Key *
-load_private_key_autodetect(const char *filename)
+
+/* Demote private to public keys for network child */
+void
+demote_sensitive_data(void)
{
- struct stat st;
- int type;
- Key *public, *private;
+ Key *tmp;
+ int i;
- if (stat(filename, &st) < 0) {
- perror(filename);
- return NULL;
+ if (sensitive_data.server_key) {
+ tmp = key_demote(sensitive_data.server_key);
+ key_free(sensitive_data.server_key);
+ sensitive_data.server_key = tmp;
}
- /*
- * try to load the public key. right now this only works for RSA1,
- * since SSH2 keys are fully encrypted
- */
- type = KEY_RSA1;
- public = key_new(type);
- if (!load_public_key(filename, public, NULL)) {
- /* ok, so we will assume this is 'some' key */
- type = KEY_UNSPEC;
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ if (sensitive_data.host_keys[i]) {
+ tmp = key_demote(sensitive_data.host_keys[i]);
+ key_free(sensitive_data.host_keys[i]);
+ sensitive_data.host_keys[i] = tmp;
+ if (tmp->type == KEY_RSA1)
+ sensitive_data.ssh1_host_key = tmp;
+ }
}
- key_free(public);
-
- /* Ok, try key with empty passphrase */
- private = key_new(type);
- if (load_private_key(filename, "", private, NULL)) {
- debug("load_private_key_autodetect: type %d %s",
- private->type, key_type(private));
- return private;
+
+ /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
+}
+
+static void
+privsep_preauth_child(void)
+{
+ u_int32_t rand[256];
+ int i;
+ struct passwd *pw;
+
+ /* Enable challenge-response authentication for privilege separation */
+ privsep_challenge_enable();
+
+ for (i = 0; i < 256; i++)
+ rand[i] = arc4random();
+ RAND_seed(rand, sizeof(rand));
+
+ /* Demote the private keys to public keys. */
+ demote_sensitive_data();
+
+ if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
+ fatal("%s: no user", SSH_PRIVSEP_USER);
+ memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
+ endpwent();
+
+ /* Change our root directory*/
+ if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
+ fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
+ strerror(errno));
+ if (chdir("/") == -1)
+ fatal("chdir(\"/\"): %s", strerror(errno));
+
+ /* Drop our privileges */
+ debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
+ (u_int)pw->pw_gid);
+ do_setusercontext(pw);
+}
+
+static Authctxt*
+privsep_preauth(void)
+{
+ Authctxt *authctxt = NULL;
+ int status;
+ pid_t pid;
+
+ /* Set up unprivileged child process to deal with network data */
+ monitor = monitor_init();
+ /* Store a pointer to the kex for later rekeying */
+ monitor->m_pkex = &xxx_kex;
+
+ pid = fork();
+ if (pid == -1) {
+ fatal("fork of unprivileged child failed");
+ } else if (pid != 0) {
+ debug2("Network child is on pid %d", pid);
+
+ close(monitor->m_recvfd);
+ authctxt = monitor_child_preauth(monitor);
+ close(monitor->m_sendfd);
+
+ /* Sync memory */
+ monitor_sync(monitor);
+
+ /* Wait for the child's exit status */
+ waitpid(pid, &status, 0);
+
+ return (authctxt);
+ } else {
+ /* child */
+
+ close(monitor->m_sendfd);
+
+ /* Demote the child */
+ if (getuid() == 0 || geteuid() == 0)
+ privsep_preauth_child();
+ setproctitle("%s", "[net]");
}
- key_free(private);
- return NULL;
+ return (NULL);
}
-char *
+static void
+privsep_postauth(Authctxt *authctxt)
+{
+ extern Authctxt *x_authctxt;
+
+ /* XXX - Remote port forwarding */
+ x_authctxt = authctxt;
+
+ if (authctxt->pw->pw_uid == 0 || options.use_login) {
+ /* File descriptor passing is broken or root login */
+ monitor_apply_keystate(monitor);
+ use_privsep = 0;
+ return;
+ }
+
+ /* Authentication complete */
+ alarm(0);
+ if (startup_pipe != -1) {
+ close(startup_pipe);
+ startup_pipe = -1;
+ }
+
+ /* New socket pair */
+ monitor_reinit(monitor);
+
+ monitor->m_pid = fork();
+ if (monitor->m_pid == -1)
+ fatal("fork of unprivileged child failed");
+ else if (monitor->m_pid != 0) {
+ debug2("User child is on pid %d", monitor->m_pid);
+ close(monitor->m_recvfd);
+ monitor_child_postauth(monitor);
+
+ /* NEVERREACHED */
+ exit(0);
+ }
+
+ close(monitor->m_sendfd);
+
+ /* Demote the private keys to public keys. */
+ demote_sensitive_data();
+
+ /* Drop privileges */
+ do_setusercontext(authctxt->pw);
+
+ /* It is safe now to apply the key state */
+ monitor_apply_keystate(monitor);
+}
+
+static char *
list_hostkey_types(void)
{
- static char buf[1024];
+ Buffer b;
+ char *p;
int i;
- buf[0] = '\0';
- for(i = 0; i < options.num_host_key_files; i++) {
+
+ buffer_init(&b);
+ for (i = 0; i < options.num_host_key_files; i++) {
Key *key = sensitive_data.host_keys[i];
if (key == NULL)
continue;
- switch(key->type) {
+ switch (key->type) {
case KEY_RSA:
case KEY_DSA:
- strlcat(buf, key_ssh_name(key), sizeof buf);
- strlcat(buf, ",", sizeof buf);
+ if (buffer_len(&b) > 0)
+ buffer_append(&b, ",", 1);
+ p = key_ssh_name(key);
+ buffer_append(&b, p, strlen(p));
break;
}
}
- i = strlen(buf);
- if (i > 0 && buf[i-1] == ',')
- buf[i-1] = '\0';
- debug("list_hostkey_types: %s", buf);
- return buf;
+ buffer_append(&b, "\0", 1);
+ p = xstrdup(buffer_ptr(&b));
+ buffer_free(&b);
+ debug("list_hostkey_types: %s", p);
+ return p;
}
Key *
get_hostkey_by_type(int type)
{
int i;
- for(i = 0; i < options.num_host_key_files; i++) {
+ for (i = 0; i < options.num_host_key_files; i++) {
Key *key = sensitive_data.host_keys[i];
if (key != NULL && key->type == type)
return key;
return NULL;
}
+Key *
+get_hostkey_by_index(int ind)
+{
+ if (ind < 0 || ind >= options.num_host_key_files)
+ return (NULL);
+ return (sensitive_data.host_keys[ind]);
+}
+
+int
+get_hostkey_index(Key *key)
+{
+ int i;
+ for (i = 0; i < options.num_host_key_files; i++) {
+ if (key == sensitive_data.host_keys[i])
+ return (i);
+ }
+ return (-1);
+}
+
/*
* returns 1 if connection should be dropped, 0 otherwise.
* dropping starts at connection #max_startups_begin with a probability
* of (max_startups_rate/100). the probability increases linearly until
* all connections are dropped for startups > max_startups
*/
-int
+static int
drop_connection(int startups)
{
double p, r;
return (r < p) ? 1 : 0;
}
-int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */
-int startup_pipe; /* in child */
+static void
+usage(void)
+{
+ fprintf(stderr, "sshd version %s\n", SSH_VERSION);
+ fprintf(stderr, "Usage: %s [options]\n", __progname);
+ fprintf(stderr, "Options:\n");
+ fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
+ fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
+ fprintf(stderr, " -i Started from inetd\n");
+ fprintf(stderr, " -D Do not fork into daemon mode\n");
+ fprintf(stderr, " -t Only test configuration file and keys\n");
+ fprintf(stderr, " -q Quiet (no logging)\n");
+ fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
+ fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
+ fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
+ fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
+ fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
+ _PATH_HOST_KEY_FILE);
+ fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
+ fprintf(stderr, " -4 Use IPv4 only\n");
+ fprintf(stderr, " -6 Use IPv6 only\n");
+ fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
+ exit(1);
+}
/*
* Main program for the daemon.
int listen_sock, maxfd;
int startup_p[2];
int startups = 0;
+ Authctxt *authctxt;
+ Key *key;
int ret, key_used = 0;
__progname = get_progname(av[0]);
initialize_server_options(&options);
/* Parse command-line arguments. */
- while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != -1) {
+ while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) {
switch (opt) {
case '4':
IPv4or6 = AF_INET;
case 'D':
no_daemon_flag = 1;
break;
+ case 'e':
+ log_stderr = 1;
+ break;
case 'i':
inetd_flag = 1;
break;
fprintf(stderr, "too many ports.\n");
exit(1);
}
- options.ports[options.num_ports++] = atoi(optarg);
+ options.ports[options.num_ports++] = a2port(optarg);
+ if (options.ports[options.num_ports-1] == 0) {
+ fprintf(stderr, "Bad port number.\n");
+ exit(1);
+ }
break;
case 'g':
- options.login_grace_time = atoi(optarg);
+ if ((options.login_grace_time = convtime(optarg)) == -1) {
+ fprintf(stderr, "Invalid login grace time.\n");
+ exit(1);
+ }
break;
case 'k':
- options.key_regeneration_time = atoi(optarg);
+ if ((options.key_regeneration_time = convtime(optarg)) == -1) {
+ fprintf(stderr, "Invalid key regeneration interval.\n");
+ exit(1);
+ }
break;
case 'h':
if (options.num_host_key_files >= MAX_HOSTKEYS) {
/* only makes sense with inetd_flag, i.e. no listen() */
inetd_flag = 1;
break;
+ case 't':
+ test_flag = 1;
+ break;
case 'u':
utmp_len = atoi(optarg);
break;
+ case 'o':
+ if (process_server_config_line(&options, optarg,
+ "command-line", 0) != 0)
+ exit(1);
+ break;
case '?':
default:
- fprintf(stderr, "sshd version %s\n", SSH_VERSION);
- fprintf(stderr, "Usage: %s [options]\n", __progname);
- fprintf(stderr, "Options:\n");
- fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
- fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
- fprintf(stderr, " -i Started from inetd\n");
- fprintf(stderr, " -D Do not fork into daemon mode\n");
- fprintf(stderr, " -q Quiet (no logging)\n");
- fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
- fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
- fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
- fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
- fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
- _PATH_HOST_KEY_FILE);
- fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
- fprintf(stderr, " -4 Use IPv4 only\n");
- fprintf(stderr, " -6 Use IPv6 only\n");
- exit(1);
+ usage();
+ break;
}
}
+ SSLeay_add_all_algorithms();
+ channel_set_af(IPv4or6);
/*
* Force logging to stderr until we have loaded the private host
* key (unless started from inetd)
*/
log_init(__progname,
- options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
- options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
+ options.log_level == SYSLOG_LEVEL_NOT_SET ?
+ SYSLOG_LEVEL_INFO : options.log_level,
+ options.log_facility == SYSLOG_FACILITY_NOT_SET ?
+ SYSLOG_FACILITY_AUTH : options.log_facility,
!inetd_flag);
+#ifdef _CRAY
+ /* Cray can define user privs drop all prives now!
+ * Not needed on PRIV_SU systems!
+ */
+ drop_cray_privs();
+#endif
+
+ seed_rng();
+
/* Read server configuration options from the configuration file. */
read_server_config(&options, config_file_name);
/* 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++)
+ 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_key_autodetect(options.host_key_files[i]);
+ for (i = 0; i < options.num_host_key_files; i++) {
+ key = key_load_private(options.host_key_files[i], "", NULL);
+ sensitive_data.host_keys[i] = key;
if (key == NULL) {
- error("Could not load host key: %.200s: %.100s",
- options.host_key_files[i], strerror(errno));
+ error("Could not load host key: %s",
+ options.host_key_files[i]);
+ sensitive_data.host_keys[i] = NULL;
continue;
}
- switch(key->type){
+ switch (key->type) {
case KEY_RSA1:
sensitive_data.ssh1_host_key = key;
sensitive_data.have_ssh1_key = 1;
sensitive_data.have_ssh2_key = 1;
break;
}
- sensitive_data.host_keys[i] = key;
+ 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_2;
}
if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
- log("sshd: no hostkeys available -- exiting.\n");
+ log("sshd: no hostkeys available -- exiting.");
exit(1);
}
}
}
+ /* Configuration looks good, so exit if in test mode. */
+ if (test_flag)
+ exit(0);
+
#ifdef HAVE_SCO_PROTECTED_PW
(void) set_auth_parameters(ac, av);
#endif
unmounted if desired. */
chdir("/");
+ /* ignore SIGPIPE */
+ signal(SIGPIPE, SIG_IGN);
+
/* Start listening for a socket, unless started from inetd. */
if (inetd_flag) {
- int s1, s2;
+ int s1;
s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
- s2 = dup(s1);
+ dup(s1);
sock_in = dup(0);
sock_out = dup(1);
startup_pipe = -1;
*/
debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
if (options.protocol & SSH_PROTO_1)
- generate_empheral_server_key();
+ 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)
* close.
*/
setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
- (void *) &on, sizeof(on));
+ &on, sizeof(on));
linger.l_onoff = 1;
linger.l_linger = 5;
setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
- (void *) &linger, sizeof(linger));
+ &linger, sizeof(linger));
debug("Bind to port %s on %s.", strport, ntop);
/* Bind the socket to the desired port. */
- if ((bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) &&
- (!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 (!num_listen_socks)
fatal("Cannot bind any address.");
+ 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);
+
+ /* Arrange SIGCHLD to be caught. */
+ signal(SIGCHLD, main_sigchld_handler);
+
+ /* Write out the pid file after the sigterm handler is setup */
if (!debug_flag) {
/*
* Record our pid in /var/run/sshd.pid to make it
fclose(f);
}
}
- if (options.protocol & SSH_PROTO_1)
- generate_empheral_server_key();
-
- /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
- signal(SIGHUP, sighup_handler);
-
- signal(SIGTERM, sigterm_handler);
- signal(SIGQUIT, sigterm_handler);
-
- /* Arrange SIGCHLD to be caught. */
- signal(SIGCHLD, main_sigchld_handler);
/* setup fd set for listen */
fdset = NULL;
ret = select(maxfd+1, fdset, NULL, NULL, NULL);
if (ret < 0 && errno != EINTR)
error("select: %.100s", strerror(errno));
+ if (received_sigterm) {
+ log("Received signal %d; terminating.",
+ (int) received_sigterm);
+ close_listen_socks();
+ unlink(options.pid_file);
+ exit(255);
+ }
if (key_used && key_do_regen) {
- generate_empheral_server_key();
+ generate_ephemeral_server_key();
key_used = 0;
key_do_regen = 0;
}
}
if (fcntl(newsock, F_SETFL, 0) < 0) {
error("newsock del O_NONBLOCK: %s", strerror(errno));
+ close(newsock);
continue;
}
if (drop_connection(startups) == 1) {
* the connection.
*/
startup_pipe = startup_p[1];
- for (j = 0; j < options.max_startups; j++)
- if (startup_pipes[j] != -1)
- close(startup_pipes[j]);
+ close_startup_pipes();
close_listen_socks();
sock_in = newsock;
sock_out = newsock;
/* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
linger.l_onoff = 1;
linger.l_linger = 5;
- setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
+ setsockopt(sock_in, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
/* Set keepalives if requested. */
if (options.keepalives &&
- setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
+ setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
sizeof(on)) < 0)
error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
remote_port = get_remote_port();
remote_ip = get_remote_ipaddr();
- /* Check whether logins are denied from this host. */
#ifdef LIBWRAP
- /* XXX LIBWRAP noes not know about IPv6 */
+ /* Check whether logins are denied from this host. */
{
struct request_info req;
- request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL);
+ request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
fromhost(&req);
if (!hosts_access(&req)) {
- close(sock_in);
- close(sock_out);
+ debug("Connection refused by tcp wrapper");
refuse(&req);
+ /* NOTREACHED */
+ fatal("libwrap refuse returns");
}
-/*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
}
#endif /* LIBWRAP */
+
/* Log the connection. */
verbose("Connection from %.500s port %d", remote_ip, remote_port);
* 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) {
+ if (options.rhosts_authentication &&
+ (remote_port >= IPPORT_RESERVED ||
+ remote_port < IPPORT_RESERVED / 2)) {
debug("Rhosts Authentication disabled, "
- "originating port not trusted.");
+ "originating port %d not trusted.", remote_port);
options.rhosts_authentication = 0;
}
-#ifdef KRB4
+#if defined(KRB4) && !defined(KRB5)
if (!packet_connection_is_ipv4() &&
options.kerberos_authentication) {
debug("Kerberos Authentication disabled, only available for IPv4.");
options.kerberos_authentication = 0;
}
-#endif /* KRB4 */
+#endif /* KRB4 && !KRB5 */
#ifdef AFS
/* If machine has AFS, set process authentication group. */
if (k_hasafs()) {
packet_set_nonblocking();
+ if (use_privsep)
+ if ((authctxt = privsep_preauth()) != NULL)
+ goto authenticated;
+
/* perform the key exchange */
/* authenticate user and start session */
if (compat20) {
do_ssh2_kex();
- do_authentication2();
+ authctxt = do_authentication2();
} else {
do_ssh1_kex();
- do_authentication();
+ authctxt = do_authentication();
+ }
+ /*
+ * If we use privilege separation, the unprivileged child transfers
+ * the current keystate and exits
+ */
+ if (use_privsep) {
+ mm_send_keystate(monitor);
+ exit(0);
+ }
+
+ authenticated:
+ /*
+ * In privilege separation, we fork another child and prepare
+ * file descriptor passing.
+ */
+ if (use_privsep) {
+ privsep_postauth(authctxt);
+ /* the monitor process [priv] will not return */
+ if (!compat20)
+ destroy_sensitive_data();
}
-#ifdef KRB4
- /* Cleanup user's ticket cache file. */
- if (options.kerberos_ticket_cleanup)
- (void) dest_tkt();
-#endif /* KRB4 */
+ /* Perform session preparation. */
+ do_authenticated(authctxt);
/* The connection has been terminated. */
verbose("Closing connection to %.100s", remote_ip);
#endif /* USE_PAM */
packet_close();
+
+ if (use_privsep)
+ mm_terminate();
+
exit(0);
}
+/*
+ * Decrypt session_key_int using our private server key and private host key
+ * (key with larger modulus first).
+ */
+int
+ssh1_session_key(BIGNUM *session_key_int)
+{
+ int rsafail = 0;
+
+ if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
+ /* Server key has bigger modulus. */
+ if (BN_num_bits(sensitive_data.server_key->rsa->n) <
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
+ fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
+ get_remote_ipaddr(),
+ BN_num_bits(sensitive_data.server_key->rsa->n),
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
+ SSH_KEY_BITS_RESERVED);
+ }
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.server_key->rsa) <= 0)
+ rsafail++;
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.ssh1_host_key->rsa) <= 0)
+ rsafail++;
+ } else {
+ /* Host key has bigger modulus (or they are equal). */
+ if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
+ BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
+ fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
+ get_remote_ipaddr(),
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
+ BN_num_bits(sensitive_data.server_key->rsa->n),
+ SSH_KEY_BITS_RESERVED);
+ }
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.ssh1_host_key->rsa) < 0)
+ rsafail++;
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.server_key->rsa) < 0)
+ rsafail++;
+ }
+ return (rsafail);
+}
/*
* SSH1 key exchange
*/
-void
+static void
do_ssh1_kex(void)
{
int i, len;
- int plen, slen;
int rsafail = 0;
BIGNUM *session_key_int;
u_char session_key[SSH_SESSION_KEY_LENGTH];
auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
if (options.rsa_authentication)
auth_mask |= 1 << SSH_AUTH_RSA;
-#ifdef KRB4
+#if defined(KRB4) || defined(KRB5)
if (options.kerberos_authentication)
auth_mask |= 1 << SSH_AUTH_KERBEROS;
#endif
-#ifdef AFS
+#if defined(AFS) || defined(KRB5)
if (options.kerberos_tgt_passing)
auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
+#endif
+#ifdef AFS
if (options.afs_token_passing)
auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
#endif
- if (options.challenge_reponse_authentication == 1)
+ if (options.challenge_response_authentication == 1)
auth_mask |= 1 << SSH_AUTH_TIS;
if (options.password_authentication)
auth_mask |= 1 << SSH_AUTH_PASSWORD;
BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
/* Read clients reply (cipher type and session key). */
- packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
+ packet_read_expect(SSH_CMSG_SESSION_KEY);
/* Get cipher type and check whether we accept this. */
cipher_type = packet_get_char();
debug("Encryption type: %.200s", cipher_name(cipher_type));
/* Get the encrypted integer. */
- session_key_int = BN_new();
- packet_get_bignum(session_key_int, &slen);
+ if ((session_key_int = BN_new()) == NULL)
+ fatal("do_ssh1_kex: BN_new failed");
+ packet_get_bignum(session_key_int);
protocol_flags = packet_get_int();
packet_set_protocol_flags(protocol_flags);
+ packet_check_eom();
- packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
-
- /*
- * Decrypt it using our private server key and private host key (key
- * with larger modulus first).
- */
- if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
- /* Server key has bigger modulus. */
- if (BN_num_bits(sensitive_data.server_key->rsa->n) <
- BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
- fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
- get_remote_ipaddr(),
- BN_num_bits(sensitive_data.server_key->rsa->n),
- BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
- SSH_KEY_BITS_RESERVED);
- }
- if (rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.server_key->rsa) <= 0)
- rsafail++;
- if (rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.ssh1_host_key->rsa) <= 0)
- rsafail++;
- } else {
- /* Host key has bigger modulus (or they are equal). */
- if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
- BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
- fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
- get_remote_ipaddr(),
- BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
- BN_num_bits(sensitive_data.server_key->rsa->n),
- SSH_KEY_BITS_RESERVED);
- }
- if (rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.ssh1_host_key->rsa) < 0)
- rsafail++;
- if (rsa_private_decrypt(session_key_int, session_key_int,
- sensitive_data.server_key->rsa) < 0)
- rsafail++;
- }
-
- compute_session_id(session_id, cookie,
- sensitive_data.ssh1_host_key->rsa->n,
- sensitive_data.server_key->rsa->n);
-
- /* Destroy the private and public keys. They will no longer be needed. */
- destroy_sensitive_data();
+ /* Decrypt session_key_int using host/server keys */
+ rsafail = PRIVSEP(ssh1_session_key(session_key_int));
/*
* Extract session key from the decrypted integer. The key is in the
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);
+ u_char *buf = xmalloc(bytes);
+ MD5_CTX md;
+
log("do_connection: generating a fake encryption key");
- for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
- if (i % 4 == 0)
- rand = arc4random();
- session_key[i] = rand & 0xff;
- rand >>= 8;
- }
+ 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. No longer. */
+ destroy_sensitive_data();
+
+ if (use_privsep)
+ mm_ssh1_session_id(session_id);
+
/* Destroy the decrypted integer. It is no longer needed. */
BN_clear_free(session_key_int);
- /* 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
+static void
do_ssh2_kex(void)
{
- Buffer *server_kexinit;
- Buffer *client_kexinit;
- int payload_len;
- int i;
Kex *kex;
- char *cprop[PROPOSAL_MAX];
-
-/* KEXINIT */
if (options.ciphers != NULL) {
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
}
+ myproposal[PROPOSAL_ENC_ALGS_CTOS] =
+ compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
+ myproposal[PROPOSAL_ENC_ALGS_STOC] =
+ compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
+
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();
- server_kexinit = kex_init(myproposal);
- client_kexinit = xmalloc(sizeof(*client_kexinit));
- buffer_init(client_kexinit);
+ /* start key exchange */
+ kex = kex_setup(myproposal);
+ kex->server = 1;
+ kex->client_version_string=client_version_string;
+ kex->server_version_string=server_version_string;
+ kex->load_host_key=&get_hostkey_by_type;
+ kex->host_key_index=&get_hostkey_index;
- /* algorithm negotiation */
- kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
- kex = kex_choose_conf(cprop, myproposal, 1);
- for (i = 0; i < PROPOSAL_MAX; i++)
- xfree(cprop[i]);
+ xxx_kex = kex;
- 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.");
+ dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
- debug("Wait SSH2_MSG_NEWKEYS.");
- packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
- debug("GOT SSH2_MSG_NEWKEYS.");
+ session_id2 = kex->session_id;
+ session_id2_len = kex->session_id_len;
#ifdef DEBUG_KEXDH
/* send 1st encrypted/maced/compressed message */
packet_send();
packet_write_wait();
#endif
-
- debug("done: KEX2.");
-}
-
-/*
- * SSH2 key exchange
- */
-
-/* diffie-hellman-group1-sha1 */
-
-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;
-
- 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);
-
- debug("Wait SSH2_MSG_KEXDH_INIT.");
- packet_read_expect(&payload_len, SSH2_MSG_KEXDH_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
- 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(
- 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,
- 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_KEXDH_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();
-
- kex_derive_keys(kex, hash, shared_secret);
- BN_clear_free(shared_secret);
- packet_set_kex(kex);
-
- /* have keys, free DH */
- DH_free(dh);
-}
-
-/* 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();
-
- /* Compute our exchange value in parallel with the client */
-
- dh_gen_key(dh);
-
- 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
- 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();
-
- kex_derive_keys(kex, hash, shared_secret);
- BN_clear_free(shared_secret);
- packet_set_kex(kex);
-
- /* have keys, free DH */
- DH_free(dh);
+ debug("KEX done");
}
andersk / openssh.git / blobdiff