--- /dev/null
+/* $OpenBSD: sshd.c,v 1.385 2011/06/23 09:34:13 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * 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.
+ *
+ * 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:
+ * Privilege Separation:
+ *
+ * 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
+ * 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"
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#include "openbsd-compat/sys-tree.h"
+#include "openbsd-compat/sys-queue.h"
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <grp.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <openssl/dh.h>
+#include <openssl/bn.h>
+#include <openssl/md5.h>
+#include <openssl/rand.h>
+#include "openbsd-compat/openssl-compat.h"
+
+#ifdef HAVE_SECUREWARE
+#include <sys/security.h>
+#include <prot.h>
+#endif
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "ssh1.h"
+#include "ssh2.h"
+#include "rsa.h"
+#include "sshpty.h"
+#include "packet.h"
+#include "log.h"
+#include "buffer.h"
+#include "servconf.h"
+#include "uidswap.h"
+#include "compat.h"
+#include "cipher.h"
+#include "key.h"
+#include "kex.h"
+#include "dh.h"
+#include "myproposal.h"
+#include "authfile.h"
+#include "pathnames.h"
+#include "atomicio.h"
+#include "canohost.h"
+#include "hostfile.h"
+#include "auth.h"
+#include "misc.h"
+#include "msg.h"
+#include "dispatch.h"
+#include "channels.h"
+#include "session.h"
+#include "monitor_mm.h"
+#include "monitor.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+#include "monitor_wrap.h"
+#include "roaming.h"
+#include "ssh-sandbox.h"
+#include "version.h"
+
+#ifdef LIBWRAP
+#include <tcpd.h>
+#include <syslog.h>
+int allow_severity;
+int deny_severity;
+#endif /* LIBWRAP */
+
+#ifndef O_NOCTTY
+#define O_NOCTTY 0
+#endif
+
+/* Re-exec fds */
+#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
+#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
+#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
+#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
+
+extern char *__progname;
+
+/* Server configuration options. */
+ServerOptions options;
+
+/* Name of the server configuration file. */
+char *config_file_name = _PATH_SERVER_CONFIG_FILE;
+
+/*
+ * Debug mode flag. This can be set on the command line. If debug
+ * mode is enabled, extra debugging output will be sent to the system
+ * log, the daemon will not go to background, and will exit after processing
+ * the first connection.
+ */
+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;
+
+/* 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;
+
+/* Saved arguments to main(). */
+char **saved_argv;
+int saved_argc;
+
+/* re-exec */
+int rexeced_flag = 0;
+int rexec_flag = 1;
+int rexec_argc = 0;
+char **rexec_argv;
+
+/*
+ * The sockets that the server is listening; this is used in the SIGHUP
+ * signal handler.
+ */
+#define MAX_LISTEN_SOCKS 16
+int listen_socks[MAX_LISTEN_SOCKS];
+int num_listen_socks = 0;
+
+/*
+ * the client's version string, passed by sshd2 in compat mode. if != NULL,
+ * sshd will skip the version-number exchange
+ */
+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
+ * that the pages do not get written into swap. However, there are some
+ * problems. The private key contains BIGNUMs, and we do not (in principle)
+ * have access to the internals of them, and locking just the structure is
+ * not very useful. Currently, memory locking is not implemented.
+ */
+struct {
+ Key *server_key; /* ephemeral server key */
+ Key *ssh1_host_key; /* ssh1 host key */
+ Key **host_keys; /* all private host keys */
+ Key **host_certificates; /* all public host certificates */
+ 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.
+ */
+static volatile sig_atomic_t key_do_regen = 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];
+
+/* same for ssh2 */
+u_char *session_id2 = NULL;
+u_int session_id2_len = 0;
+
+/* record remote hostname or ip */
+u_int utmp_len = MAXHOSTNAMELEN;
+
+/* options.max_startup sized array of fd ints */
+int *startup_pipes = NULL;
+int startup_pipe; /* in child */
+
+/* variables used for privilege separation */
+int use_privsep = -1;
+struct monitor *pmonitor = NULL;
+
+/* global authentication context */
+Authctxt *the_authctxt = NULL;
+
+/* sshd_config buffer */
+Buffer cfg;
+
+/* message to be displayed after login */
+Buffer loginmsg;
+
+/* Unprivileged user */
+struct passwd *privsep_pw = NULL;
+
+/* Prototypes for various functions defined later in this file. */
+void destroy_sensitive_data(void);
+void demote_sensitive_data(void);
+
+static void do_ssh1_kex(void);
+static void do_ssh2_kex(void);
+
+/*
+ * Close all listening sockets
+ */
+static void
+close_listen_socks(void)
+{
+ int i;
+
+ for (i = 0; i < num_listen_socks; i++)
+ close(listen_socks[i]);
+ num_listen_socks = -1;
+}
+
+static void
+close_startup_pipes(void)
+{
+ int i;
+
+ if (startup_pipes)
+ for (i = 0; i < options.max_startups; i++)
+ if (startup_pipes[i] != -1)
+ close(startup_pipes[i]);
+}
+
+/*
+ * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
+ * the effect is to reread the configuration file (and to regenerate
+ * the server key).
+ */
+
+/*ARGSUSED*/
+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.
+ */
+static void
+sighup_restart(void)
+{
+ logit("Received SIGHUP; restarting.");
+ close_listen_socks();
+ close_startup_pipes();
+ alarm(0); /* alarm timer persists across exec */
+ signal(SIGHUP, SIG_IGN); /* will be restored after exec */
+ execv(saved_argv[0], saved_argv);
+ logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
+ strerror(errno));
+ exit(1);
+}
+
+/*
+ * Generic signal handler for terminating signals in the master daemon.
+ */
+/*ARGSUSED*/
+static void
+sigterm_handler(int sig)
+{
+ received_sigterm = sig;
+}
+
+/*
+ * SIGCHLD handler. This is called whenever a child dies. This will then
+ * reap any zombies left by exited children.
+ */
+/*ARGSUSED*/
+static void
+main_sigchld_handler(int sig)
+{
+ int save_errno = errno;
+ pid_t pid;
+ int status;
+
+ while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
+ (pid < 0 && errno == EINTR))
+ ;
+
+ signal(SIGCHLD, main_sigchld_handler);
+ errno = save_errno;
+}
+
+/*
+ * Signal handler for the alarm after the login grace period has expired.
+ */
+/*ARGSUSED*/
+static void
+grace_alarm_handler(int sig)
+{
+ if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
+ kill(pmonitor->m_pid, SIGALRM);
+
+ /* Log error and exit. */
+ sigdie("Timeout before authentication for %s", get_remote_ipaddr());
+}
+
+/*
+ * Signal handler for the key regeneration alarm. Note that this
+ * alarm only occurs in the daemon waiting for connections, and it does not
+ * do anything with the private key or random state before forking.
+ * Thus there should be no concurrency control/asynchronous execution
+ * problems.
+ */
+static void
+generate_ephemeral_server_key(void)
+{
+ 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);
+ verbose("RSA key generation complete.");
+
+ arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
+ arc4random_stir();
+}
+
+/*ARGSUSED*/
+static void
+key_regeneration_alarm(int sig)
+{
+ int save_errno = errno;
+
+ signal(SIGALRM, SIG_DFL);
+ errno = save_errno;
+ key_do_regen = 1;
+}
+
+static void
+sshd_exchange_identification(int sock_in, int sock_out)
+{
+ u_int i;
+ int mismatch;
+ int remote_major, remote_minor;
+ int major, minor;
+ char *s, *newline = "\n";
+ char buf[256]; /* Must not be larger than remote_version. */
+ char remote_version[256]; /* Must be at least as big as buf. */
+
+ if ((options.protocol & SSH_PROTO_1) &&
+ (options.protocol & SSH_PROTO_2)) {
+ major = PROTOCOL_MAJOR_1;
+ minor = 99;
+ } else if (options.protocol & SSH_PROTO_2) {
+ major = PROTOCOL_MAJOR_2;
+ minor = PROTOCOL_MINOR_2;
+ newline = "\r\n";
+ } else {
+ major = PROTOCOL_MAJOR_1;
+ minor = PROTOCOL_MINOR_1;
+ }
+ snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor,
+ SSH_VERSION, newline);
+ server_version_string = xstrdup(buf);
+
+ /* Send our protocol version identification. */
+ if (roaming_atomicio(vwrite, sock_out, server_version_string,
+ strlen(server_version_string))
+ != strlen(server_version_string)) {
+ logit("Could not write ident string to %s", get_remote_ipaddr());
+ cleanup_exit(255);
+ }
+
+ /* Read other sides version identification. */
+ memset(buf, 0, sizeof(buf));
+ for (i = 0; i < sizeof(buf) - 1; i++) {
+ if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) {
+ logit("Did not receive identification string from %s",
+ get_remote_ipaddr());
+ cleanup_exit(255);
+ }
+ if (buf[i] == '\r') {
+ buf[i] = 0;
+ /* Kludge for F-Secure Macintosh < 1.0.2 */
+ if (i == 12 &&
+ strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
+ break;
+ continue;
+ }
+ if (buf[i] == '\n') {
+ buf[i] = 0;
+ break;
+ }
+ }
+ buf[sizeof(buf) - 1] = 0;
+ client_version_string = xstrdup(buf);
+
+ /*
+ * Check that the versions match. In future this might accept
+ * several versions and set appropriate flags to handle them.
+ */
+ if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
+ &remote_major, &remote_minor, remote_version) != 3) {
+ s = "Protocol mismatch.\n";
+ (void) atomicio(vwrite, sock_out, s, strlen(s));
+ close(sock_in);
+ close(sock_out);
+ logit("Bad protocol version identification '%.100s' from %s",
+ client_version_string, get_remote_ipaddr());
+ cleanup_exit(255);
+ }
+ debug("Client protocol version %d.%d; client software version %.100s",
+ remote_major, remote_minor, remote_version);
+
+ compat_datafellows(remote_version);
+
+ if (datafellows & SSH_BUG_PROBE) {
+ logit("probed from %s with %s. Don't panic.",
+ get_remote_ipaddr(), client_version_string);
+ cleanup_exit(255);
+ }
+
+ if (datafellows & SSH_BUG_SCANNER) {
+ logit("scanned from %s with %s. Don't panic.",
+ get_remote_ipaddr(), client_version_string);
+ cleanup_exit(255);
+ }
+
+ 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 "
+ "is no longer supported. Please install a newer version.");
+ } else if (remote_minor == 3) {
+ /* note that this disables agent-forwarding */
+ enable_compat13();
+ }
+ break;
+ case 2:
+ if (options.protocol & SSH_PROTO_2) {
+ enable_compat20();
+ break;
+ }
+ /* FALLTHROUGH */
+ default:
+ mismatch = 1;
+ break;
+ }
+ chop(server_version_string);
+ debug("Local version string %.200s", server_version_string);
+
+ if (mismatch) {
+ s = "Protocol major versions differ.\n";
+ (void) atomicio(vwrite, sock_out, s, strlen(s));
+ close(sock_in);
+ close(sock_out);
+ logit("Protocol major versions differ for %s: %.200s vs. %.200s",
+ get_remote_ipaddr(),
+ server_version_string, client_version_string);
+ cleanup_exit(255);
+ }
+}
+
+/* Destroy the host and server keys. They will no longer be needed. */
+void
+destroy_sensitive_data(void)
+{
+ 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;
+ }
+ if (sensitive_data.host_certificates[i]) {
+ key_free(sensitive_data.host_certificates[i]);
+ sensitive_data.host_certificates[i] = NULL;
+ }
+ }
+ sensitive_data.ssh1_host_key = NULL;
+ memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
+}
+
+/* Demote private to public keys for network child */
+void
+demote_sensitive_data(void)
+{
+ Key *tmp;
+ int i;
+
+ if (sensitive_data.server_key) {
+ tmp = key_demote(sensitive_data.server_key);
+ key_free(sensitive_data.server_key);
+ sensitive_data.server_key = tmp;
+ }
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ if (sensitive_data.host_keys[i]) {
+ tmp = key_demote(sensitive_data.host_keys[i]);
+ key_free(sensitive_data.host_keys[i]);
+ sensitive_data.host_keys[i] = tmp;
+ if (tmp->type == KEY_RSA1)
+ sensitive_data.ssh1_host_key = tmp;
+ }
+ /* Certs do not need demotion */
+ }
+
+ /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
+}
+
+static void
+privsep_preauth_child(void)
+{
+ u_int32_t rnd[256];
+ gid_t gidset[1];
+
+ /* Enable challenge-response authentication for privilege separation */
+ privsep_challenge_enable();
+
+ arc4random_stir();
+ arc4random_buf(rnd, sizeof(rnd));
+ RAND_seed(rnd, sizeof(rnd));
+
+ /* Demote the private keys to public keys. */
+ demote_sensitive_data();
+
+ /* 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)privsep_pw->pw_uid,
+ (u_int)privsep_pw->pw_gid);
+#if 0
+ /* XXX not ready, too heavy after chroot */
+ do_setusercontext(privsep_pw);
+#else
+ gidset[0] = privsep_pw->pw_gid;
+ if (setgroups(1, gidset) < 0)
+ fatal("setgroups: %.100s", strerror(errno));
+ permanently_set_uid(privsep_pw);
+#endif
+}
+
+static int
+privsep_preauth(Authctxt *authctxt)
+{
+ int status;
+ pid_t pid;
+ struct ssh_sandbox *box = NULL;
+
+ /* Set up unprivileged child process to deal with network data */
+ pmonitor = monitor_init();
+ /* Store a pointer to the kex for later rekeying */
+ pmonitor->m_pkex = &xxx_kex;
+
+ if (use_privsep == PRIVSEP_SANDBOX)
+ box = ssh_sandbox_init();
+ pid = fork();
+ if (pid == -1) {
+ fatal("fork of unprivileged child failed");
+ } else if (pid != 0) {
+ debug2("Network child is on pid %ld", (long)pid);
+
+ if (box != NULL)
+ ssh_sandbox_parent_preauth(box, pid);
+ pmonitor->m_pid = pid;
+ monitor_child_preauth(authctxt, pmonitor);
+
+ /* Sync memory */
+ monitor_sync(pmonitor);
+
+ /* Wait for the child's exit status */
+ while (waitpid(pid, &status, 0) < 0) {
+ if (errno != EINTR)
+ fatal("%s: waitpid: %s", __func__,
+ strerror(errno));
+ }
+ if (WIFEXITED(status)) {
+ if (WEXITSTATUS(status) != 0)
+ fatal("%s: preauth child exited with status %d",
+ __func__, WEXITSTATUS(status));
+ } else if (WIFSIGNALED(status))
+ fatal("%s: preauth child terminated by signal %d",
+ __func__, WTERMSIG(status));
+ if (box != NULL)
+ ssh_sandbox_parent_finish(box);
+ return 1;
+ } else {
+ /* child */
+ close(pmonitor->m_sendfd);
+ close(pmonitor->m_log_recvfd);
+
+ /* Arrange for logging to be sent to the monitor */
+ set_log_handler(mm_log_handler, pmonitor);
+
+ /* Demote the child */
+ if (getuid() == 0 || geteuid() == 0)
+ privsep_preauth_child();
+ setproctitle("%s", "[net]");
+ if (box != NULL)
+ ssh_sandbox_child(box);
+
+ return 0;
+ }
+}
+
+static void
+privsep_postauth(Authctxt *authctxt)
+{
+ u_int32_t rnd[256];
+
+#ifdef DISABLE_FD_PASSING
+ if (1) {
+#else
+ if (authctxt->pw->pw_uid == 0 || options.use_login) {
+#endif
+ /* File descriptor passing is broken or root login */
+ use_privsep = 0;
+ goto skip;
+ }
+
+ /* New socket pair */
+ monitor_reinit(pmonitor);
+
+ pmonitor->m_pid = fork();
+ if (pmonitor->m_pid == -1)
+ fatal("fork of unprivileged child failed");
+ else if (pmonitor->m_pid != 0) {
+ verbose("User child is on pid %ld", (long)pmonitor->m_pid);
+ buffer_clear(&loginmsg);
+ monitor_child_postauth(pmonitor);
+
+ /* NEVERREACHED */
+ exit(0);
+ }
+
+ /* child */
+
+ close(pmonitor->m_sendfd);
+ pmonitor->m_sendfd = -1;
+
+ /* Demote the private keys to public keys. */
+ demote_sensitive_data();
+
+ arc4random_stir();
+ arc4random_buf(rnd, sizeof(rnd));
+ RAND_seed(rnd, sizeof(rnd));
+
+ /* Drop privileges */
+ do_setusercontext(authctxt->pw);
+
+ skip:
+ /* It is safe now to apply the key state */
+ monitor_apply_keystate(pmonitor);
+
+ /*
+ * Tell the packet layer that authentication was successful, since
+ * this information is not part of the key state.
+ */
+ packet_set_authenticated();
+}
+
+static char *
+list_hostkey_types(void)
+{
+ Buffer b;
+ const char *p;
+ char *ret;
+ int i;
+ Key *key;
+
+ buffer_init(&b);
+ for (i = 0; i < options.num_host_key_files; i++) {
+ key = sensitive_data.host_keys[i];
+ if (key == NULL)
+ continue;
+ switch (key->type) {
+ case KEY_RSA:
+ case KEY_DSA:
+ case KEY_ECDSA:
+ if (buffer_len(&b) > 0)
+ buffer_append(&b, ",", 1);
+ p = key_ssh_name(key);
+ buffer_append(&b, p, strlen(p));
+ break;
+ }
+ /* If the private key has a cert peer, then list that too */
+ key = sensitive_data.host_certificates[i];
+ if (key == NULL)
+ continue;
+ switch (key->type) {
+ case KEY_RSA_CERT_V00:
+ case KEY_DSA_CERT_V00:
+ case KEY_RSA_CERT:
+ case KEY_DSA_CERT:
+ case KEY_ECDSA_CERT:
+ if (buffer_len(&b) > 0)
+ buffer_append(&b, ",", 1);
+ p = key_ssh_name(key);
+ buffer_append(&b, p, strlen(p));
+ break;
+ }
+ }
+ buffer_append(&b, "\0", 1);
+ ret = xstrdup(buffer_ptr(&b));
+ buffer_free(&b);
+ debug("list_hostkey_types: %s", ret);
+ return ret;
+}
+
+static Key *
+get_hostkey_by_type(int type, int need_private)
+{
+ int i;
+ Key *key;
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ switch (type) {
+ case KEY_RSA_CERT_V00:
+ case KEY_DSA_CERT_V00:
+ case KEY_RSA_CERT:
+ case KEY_DSA_CERT:
+ case KEY_ECDSA_CERT:
+ key = sensitive_data.host_certificates[i];
+ break;
+ default:
+ key = sensitive_data.host_keys[i];
+ break;
+ }
+ if (key != NULL && key->type == type)
+ return need_private ?
+ sensitive_data.host_keys[i] : key;
+ }
+ return NULL;
+}
+
+Key *
+get_hostkey_public_by_type(int type)
+{
+ return get_hostkey_by_type(type, 0);
+}
+
+Key *
+get_hostkey_private_by_type(int type)
+{
+ return get_hostkey_by_type(type, 1);
+}
+
+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_is_cert(key)) {
+ if (key == sensitive_data.host_certificates[i])
+ return (i);
+ } else {
+ 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
+ */
+static int
+drop_connection(int startups)
+{
+ int 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 /= options.max_startups - options.max_startups_begin;
+ p += options.max_startups_rate;
+ r = arc4random_uniform(100);
+
+ debug("drop_connection: p %d, r %d", p, r);
+ return (r < p) ? 1 : 0;
+}
+
+static void
+usage(void)
+{
+ fprintf(stderr, "%s, %s\n",
+ SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
+ fprintf(stderr,
+"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n"
+" [-f config_file] [-g login_grace_time] [-h host_key_file]\n"
+" [-k key_gen_time] [-o option] [-p port] [-u len]\n"
+ );
+ exit(1);
+}
+
+static void
+send_rexec_state(int fd, Buffer *conf)
+{
+ Buffer m;
+
+ debug3("%s: entering fd = %d config len %d", __func__, fd,
+ buffer_len(conf));
+
+ /*
+ * Protocol from reexec master to child:
+ * string configuration
+ * u_int ephemeral_key_follows
+ * bignum e (only if ephemeral_key_follows == 1)
+ * bignum n "
+ * bignum d "
+ * bignum iqmp "
+ * bignum p "
+ * bignum q "
+ * string rngseed (only if OpenSSL is not self-seeded)
+ */
+ buffer_init(&m);
+ buffer_put_cstring(&m, buffer_ptr(conf));
+
+ if (sensitive_data.server_key != NULL &&
+ sensitive_data.server_key->type == KEY_RSA1) {
+ buffer_put_int(&m, 1);
+ buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
+ buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
+ buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
+ buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
+ buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
+ buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
+ } else
+ buffer_put_int(&m, 0);
+
+#ifndef OPENSSL_PRNG_ONLY
+ rexec_send_rng_seed(&m);
+#endif
+
+ if (ssh_msg_send(fd, 0, &m) == -1)
+ fatal("%s: ssh_msg_send failed", __func__);
+
+ buffer_free(&m);
+
+ debug3("%s: done", __func__);
+}
+
+static void
+recv_rexec_state(int fd, Buffer *conf)
+{
+ Buffer m;
+ char *cp;
+ u_int len;
+
+ debug3("%s: entering fd = %d", __func__, fd);
+
+ buffer_init(&m);
+
+ if (ssh_msg_recv(fd, &m) == -1)
+ fatal("%s: ssh_msg_recv failed", __func__);
+ if (buffer_get_char(&m) != 0)
+ fatal("%s: rexec version mismatch", __func__);
+
+ cp = buffer_get_string(&m, &len);
+ if (conf != NULL)
+ buffer_append(conf, cp, len + 1);
+ xfree(cp);
+
+ if (buffer_get_int(&m)) {
+ if (sensitive_data.server_key != NULL)
+ key_free(sensitive_data.server_key);
+ sensitive_data.server_key = key_new_private(KEY_RSA1);
+ buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
+ buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
+ buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
+ buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
+ buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
+ buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
+ rsa_generate_additional_parameters(
+ sensitive_data.server_key->rsa);
+ }
+
+#ifndef OPENSSL_PRNG_ONLY
+ rexec_recv_rng_seed(&m);
+#endif
+
+ buffer_free(&m);
+
+ debug3("%s: done", __func__);
+}
+
+/* Accept a connection from inetd */
+static void
+server_accept_inetd(int *sock_in, int *sock_out)
+{
+ int fd;
+
+ startup_pipe = -1;
+ if (rexeced_flag) {
+ close(REEXEC_CONFIG_PASS_FD);
+ *sock_in = *sock_out = dup(STDIN_FILENO);
+ if (!debug_flag) {
+ startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
+ close(REEXEC_STARTUP_PIPE_FD);
+ }
+ } else {
+ *sock_in = dup(STDIN_FILENO);
+ *sock_out = dup(STDOUT_FILENO);
+ }
+ /*
+ * We intentionally do not close the descriptors 0, 1, and 2
+ * as our code for setting the descriptors won't work if
+ * ttyfd happens to be one of those.
+ */
+ if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
+ dup2(fd, STDIN_FILENO);
+ dup2(fd, STDOUT_FILENO);
+ if (fd > STDOUT_FILENO)
+ close(fd);
+ }
+ debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
+}
+
+/*
+ * Listen for TCP connections
+ */
+static void
+server_listen(void)
+{
+ int ret, listen_sock, on = 1;
+ struct addrinfo *ai;
+ char ntop[NI_MAXHOST], strport[NI_MAXSERV];
+
+ for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
+ if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
+ continue;
+ if (num_listen_socks >= MAX_LISTEN_SOCKS)
+ fatal("Too many listen sockets. "
+ "Enlarge MAX_LISTEN_SOCKS");
+ if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
+ ntop, sizeof(ntop), strport, sizeof(strport),
+ NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
+ error("getnameinfo failed: %.100s",
+ ssh_gai_strerror(ret));
+ continue;
+ }
+ /* Create socket for listening. */
+ listen_sock = socket(ai->ai_family, ai->ai_socktype,
+ ai->ai_protocol);
+ if (listen_sock < 0) {
+ /* kernel may not support ipv6 */
+ verbose("socket: %.100s", strerror(errno));
+ continue;
+ }
+ if (set_nonblock(listen_sock) == -1) {
+ close(listen_sock);
+ continue;
+ }
+ /*
+ * Set socket options.
+ * Allow local port reuse in TIME_WAIT.
+ */
+ if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
+ &on, sizeof(on)) == -1)
+ error("setsockopt SO_REUSEADDR: %s", strerror(errno));
+
+ /* Only communicate in IPv6 over AF_INET6 sockets. */
+ if (ai->ai_family == AF_INET6)
+ sock_set_v6only(listen_sock);
+
+ 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) {
+ error("Bind to port %s on %s failed: %.200s.",
+ strport, ntop, strerror(errno));
+ close(listen_sock);
+ continue;
+ }
+ listen_socks[num_listen_socks] = listen_sock;
+ num_listen_socks++;
+
+ /* Start listening on the port. */
+ if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
+ fatal("listen on [%s]:%s: %.100s",
+ ntop, strport, strerror(errno));
+ logit("Server listening on %s port %s.", ntop, strport);
+ }
+ freeaddrinfo(options.listen_addrs);
+
+ if (!num_listen_socks)
+ fatal("Cannot bind any address.");
+}
+
+/*
+ * The main TCP accept loop. Note that, for the non-debug case, returns
+ * from this function are in a forked subprocess.
+ */
+static void
+server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
+{
+ fd_set *fdset;
+ int i, j, ret, maxfd;
+ int key_used = 0, startups = 0;
+ int startup_p[2] = { -1 , -1 };
+ struct sockaddr_storage from;
+ socklen_t fromlen;
+ pid_t pid;
+
+ /* setup fd set for accept */
+ fdset = NULL;
+ maxfd = 0;
+ for (i = 0; i < num_listen_socks; i++)
+ if (listen_socks[i] > maxfd)
+ maxfd = listen_socks[i];
+ /* pipes connected to unauthenticated childs */
+ startup_pipes = xcalloc(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
+ * the daemon is killed with a signal.
+ */
+ for (;;) {
+ if (received_sighup)
+ sighup_restart();
+ if (fdset != NULL)
+ xfree(fdset);
+ fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS),
+ sizeof(fd_mask));
+
+ 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. */
+ ret = select(maxfd+1, fdset, NULL, NULL, NULL);
+ if (ret < 0 && errno != EINTR)
+ error("select: %.100s", strerror(errno));
+ if (received_sigterm) {
+ logit("Received signal %d; terminating.",
+ (int) received_sigterm);
+ close_listen_socks();
+ unlink(options.pid_file);
+ exit(received_sigterm == SIGTERM ? 0 : 255);
+ }
+ 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 != EAGAIN &&
+ errno != EWOULDBLOCK)
+ error("accept: %.100s", strerror(errno));
+ continue;
+ }
+ if (unset_nonblock(*newsock) == -1) {
+ close(*newsock);
+ continue;
+ }
+ if (drop_connection(startups) == 1) {
+ debug("drop connection #%d", startups);
+ close(*newsock);
+ continue;
+ }
+ if (pipe(startup_p) == -1) {
+ close(*newsock);
+ continue;
+ }
+
+ if (rexec_flag && socketpair(AF_UNIX,
+ SOCK_STREAM, 0, config_s) == -1) {
+ error("reexec socketpair: %s",
+ strerror(errno));
+ close(*newsock);
+ close(startup_p[0]);
+ close(startup_p[1]);
+ continue;
+ }
+
+ for (j = 0; j < options.max_startups; j++)
+ if (startup_pipes[j] == -1) {
+ startup_pipes[j] = startup_p[0];
+ if (maxfd < startup_p[0])
+ maxfd = startup_p[0];
+ startups++;
+ break;
+ }
+
+ /*
+ * 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;
+ close(startup_p[0]);
+ close(startup_p[1]);
+ startup_pipe = -1;
+ pid = getpid();
+ if (rexec_flag) {
+ send_rexec_state(config_s[0],
+ &cfg);
+ close(config_s[0]);
+ }
+ break;
+ }
+
+ /*
+ * Normal production daemon. Fork, and have
+ * the child process the connection. The
+ * parent continues listening.
+ */
+ platform_pre_fork();
+ 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.
+ */
+ platform_post_fork_child();
+ startup_pipe = startup_p[1];
+ close_startup_pipes();
+ close_listen_socks();
+ *sock_in = *newsock;
+ *sock_out = *newsock;
+ log_init(__progname,
+ options.log_level,
+ options.log_facility,
+ log_stderr);
+ if (rexec_flag)
+ close(config_s[0]);
+ break;
+ }
+
+ /* Parent. Stay in the loop. */
+ platform_post_fork_parent(pid);
+ if (pid < 0)
+ error("fork: %.100s", strerror(errno));
+ else
+ debug("Forked child %ld.", (long)pid);
+
+ close(startup_p[1]);
+
+ if (rexec_flag) {
+ send_rexec_state(config_s[0], &cfg);
+ close(config_s[0]);
+ close(config_s[1]);
+ }
+
+ /*
+ * Mark that the key has been used (it
+ * was "given" to the child).
+ */
+ if ((options.protocol & SSH_PROTO_1) &&
+ key_used == 0) {
+ /* Schedule server key regeneration alarm. */
+ signal(SIGALRM, key_regeneration_alarm);
+ alarm(options.key_regeneration_time);
+ key_used = 1;
+ }
+
+ close(*newsock);
+
+ /*
+ * Ensure that our random state differs
+ * from that of the child
+ */
+ arc4random_stir();
+ }
+
+ /* child process check (or debug mode) */
+ if (num_listen_socks < 0)
+ break;
+ }
+}
+
+
+/*
+ * Main program for the daemon.
+ */
+int
+main(int ac, char **av)
+{
+ extern char *optarg;
+ extern int optind;
+ int opt, i, j, on = 1;
+ int sock_in = -1, sock_out = -1, newsock = -1;
+ const char *remote_ip;
+ char *test_user = NULL, *test_host = NULL, *test_addr = NULL;
+ int remote_port;
+ char *line, *p, *cp;
+ int config_s[2] = { -1 , -1 };
+ u_int64_t ibytes, obytes;
+ mode_t new_umask;
+ Key *key;
+ Authctxt *authctxt;
+
+#ifdef HAVE_SECUREWARE
+ (void)set_auth_parameters(ac, av);
+#endif
+ __progname = ssh_get_progname(av[0]);
+
+ /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
+ saved_argc = ac;
+ rexec_argc = ac;
+ saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
+ for (i = 0; i < ac; i++)
+ saved_argv[i] = xstrdup(av[i]);
+ saved_argv[i] = NULL;
+
+#ifndef HAVE_SETPROCTITLE
+ /* Prepare for later setproctitle emulation */
+ compat_init_setproctitle(ac, av);
+ av = saved_argv;
+#endif
+
+ if (geteuid() == 0 && setgroups(0, NULL) == -1)
+ debug("setgroups(): %.200s", strerror(errno));
+
+ /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+ sanitise_stdfd();
+
+ /* 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:u:o:C:dDeiqrtQRT46")) != -1) {
+ switch (opt) {
+ case '4':
+ options.address_family = AF_INET;
+ break;
+ case '6':
+ options.address_family = AF_INET6;
+ break;
+ case 'f':
+ config_file_name = optarg;
+ break;
+ case 'c':
+ if (options.num_host_cert_files >= MAX_HOSTCERTS) {
+ fprintf(stderr, "too many host certificates.\n");
+ exit(1);
+ }
+ options.host_cert_files[options.num_host_cert_files++] =
+ derelativise_path(optarg);
+ break;
+ case 'd':
+ if (debug_flag == 0) {
+ debug_flag = 1;
+ options.log_level = SYSLOG_LEVEL_DEBUG1;
+ } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
+ options.log_level++;
+ break;
+ case 'D':
+ no_daemon_flag = 1;
+ break;
+ case 'e':
+ log_stderr = 1;
+ break;
+ case 'i':
+ inetd_flag = 1;
+ break;
+ case 'r':
+ rexec_flag = 0;
+ break;
+ case 'R':
+ rexeced_flag = 1;
+ inetd_flag = 1;
+ break;
+ case 'Q':
+ /* ignored */
+ break;
+ case 'q':
+ options.log_level = SYSLOG_LEVEL_QUIET;
+ break;
+ case 'b':
+ options.server_key_bits = (int)strtonum(optarg, 256,
+ 32768, NULL);
+ break;
+ case 'p':
+ options.ports_from_cmdline = 1;
+ if (options.num_ports >= MAX_PORTS) {
+ fprintf(stderr, "too many ports.\n");
+ exit(1);
+ }
+ 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':
+ if ((options.login_grace_time = convtime(optarg)) == -1) {
+ fprintf(stderr, "Invalid login grace time.\n");
+ exit(1);
+ }
+ break;
+ case 'k':
+ 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) {
+ fprintf(stderr, "too many host keys.\n");
+ exit(1);
+ }
+ options.host_key_files[options.num_host_key_files++] =
+ derelativise_path(optarg);
+ break;
+ case 't':
+ test_flag = 1;
+ break;
+ case 'T':
+ test_flag = 2;
+ break;
+ case 'C':
+ cp = optarg;
+ while ((p = strsep(&cp, ",")) && *p != '\0') {
+ if (strncmp(p, "addr=", 5) == 0)
+ test_addr = xstrdup(p + 5);
+ else if (strncmp(p, "host=", 5) == 0)
+ test_host = xstrdup(p + 5);
+ else if (strncmp(p, "user=", 5) == 0)
+ test_user = xstrdup(p + 5);
+ else {
+ fprintf(stderr, "Invalid test "
+ "mode specification %s\n", p);
+ exit(1);
+ }
+ }
+ break;
+ case 'u':
+ utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL);
+ if (utmp_len > MAXHOSTNAMELEN) {
+ fprintf(stderr, "Invalid utmp length.\n");
+ exit(1);
+ }
+ break;
+ case 'o':
+ line = xstrdup(optarg);
+ if (process_server_config_line(&options, line,
+ "command-line", 0, NULL, NULL, NULL, NULL) != 0)
+ exit(1);
+ xfree(line);
+ break;
+ case '?':
+ default:
+ usage();
+ break;
+ }
+ }
+ if (rexeced_flag || inetd_flag)
+ rexec_flag = 0;
+ if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
+ fatal("sshd re-exec requires execution with an absolute path");
+ if (rexeced_flag)
+ closefrom(REEXEC_MIN_FREE_FD);
+ else
+ closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
+
+ OpenSSL_add_all_algorithms();
+
+ /*
+ * Force logging to stderr until we have loaded the private host
+ * key (unless started from inetd)
+ */
+ log_init(__progname,
+ options.log_level == SYSLOG_LEVEL_NOT_SET ?
+ SYSLOG_LEVEL_INFO : options.log_level,
+ options.log_facility == SYSLOG_FACILITY_NOT_SET ?
+ SYSLOG_FACILITY_AUTH : options.log_facility,
+ log_stderr || !inetd_flag);
+
+ /*
+ * Unset KRB5CCNAME, otherwise the user's session may inherit it from
+ * root's environment
+ */
+ if (getenv("KRB5CCNAME") != NULL)
+ unsetenv("KRB5CCNAME");
+
+#ifdef _UNICOS
+ /* Cray can define user privs drop all privs now!
+ * Not needed on PRIV_SU systems!
+ */
+ drop_cray_privs();
+#endif
+
+ sensitive_data.server_key = NULL;
+ sensitive_data.ssh1_host_key = NULL;
+ sensitive_data.have_ssh1_key = 0;
+ sensitive_data.have_ssh2_key = 0;
+
+ /*
+ * If we're doing an extended config test, make sure we have all of
+ * the parameters we need. If we're not doing an extended test,
+ * do not silently ignore connection test params.
+ */
+ if (test_flag >= 2 &&
+ (test_user != NULL || test_host != NULL || test_addr != NULL)
+ && (test_user == NULL || test_host == NULL || test_addr == NULL))
+ fatal("user, host and addr are all required when testing "
+ "Match configs");
+ if (test_flag < 2 && (test_user != NULL || test_host != NULL ||
+ test_addr != NULL))
+ fatal("Config test connection parameter (-C) provided without "
+ "test mode (-T)");
+
+ /* Fetch our configuration */
+ buffer_init(&cfg);
+ if (rexeced_flag)
+ recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
+ else
+ load_server_config(config_file_name, &cfg);
+
+ parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
+ &cfg, NULL, NULL, NULL);
+
+ seed_rng();
+
+ /* Fill in default values for those options not explicitly set. */
+ fill_default_server_options(&options);
+
+ /* challenge-response is implemented via keyboard interactive */
+ if (options.challenge_response_authentication)
+ options.kbd_interactive_authentication = 1;
+
+ /* set default channel AF */
+ channel_set_af(options.address_family);
+
+ /* Check that there are no remaining arguments. */
+ if (optind < ac) {
+ fprintf(stderr, "Extra argument %s.\n", av[optind]);
+ exit(1);
+ }
+
+ debug("sshd version %.100s", SSH_RELEASE);
+
+ /* Store privilege separation user for later use if required. */
+ if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
+ if (use_privsep || options.kerberos_authentication)
+ fatal("Privilege separation user %s does not exist",
+ SSH_PRIVSEP_USER);
+ } else {
+ memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd));
+ privsep_pw = pwcopy(privsep_pw);
+ xfree(privsep_pw->pw_passwd);
+ privsep_pw->pw_passwd = xstrdup("*");
+ }
+ endpwent();
+
+ /* load private host keys */
+ sensitive_data.host_keys = xcalloc(options.num_host_key_files,
+ sizeof(Key *));
+ for (i = 0; i < options.num_host_key_files; i++)
+ sensitive_data.host_keys[i] = NULL;
+
+ 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: %s",
+ options.host_key_files[i]);
+ sensitive_data.host_keys[i] = NULL;
+ continue;
+ }
+ 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:
+ case KEY_ECDSA:
+ 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) {
+ logit("Disabling protocol version 1. Could not load host key");
+ options.protocol &= ~SSH_PROTO_1;
+ }
+ if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
+ logit("Disabling protocol version 2. Could not load host key");
+ options.protocol &= ~SSH_PROTO_2;
+ }
+ if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
+ logit("sshd: no hostkeys available -- exiting.");
+ exit(1);
+ }
+
+ /*
+ * Load certificates. They are stored in an array at identical
+ * indices to the public keys that they relate to.
+ */
+ sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
+ sizeof(Key *));
+ for (i = 0; i < options.num_host_key_files; i++)
+ sensitive_data.host_certificates[i] = NULL;
+
+ for (i = 0; i < options.num_host_cert_files; i++) {
+ key = key_load_public(options.host_cert_files[i], NULL);
+ if (key == NULL) {
+ error("Could not load host certificate: %s",
+ options.host_cert_files[i]);
+ continue;
+ }
+ if (!key_is_cert(key)) {
+ error("Certificate file is not a certificate: %s",
+ options.host_cert_files[i]);
+ key_free(key);
+ continue;
+ }
+ /* Find matching private key */
+ for (j = 0; j < options.num_host_key_files; j++) {
+ if (key_equal_public(key,
+ sensitive_data.host_keys[j])) {
+ sensitive_data.host_certificates[j] = key;
+ break;
+ }
+ }
+ if (j >= options.num_host_key_files) {
+ error("No matching private key for certificate: %s",
+ options.host_cert_files[i]);
+ key_free(key);
+ continue;
+ }
+ sensitive_data.host_certificates[j] = key;
+ debug("host certificate: #%d type %d %s", j, key->type,
+ key_type(key));
+ }
+ /* 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.ssh1_host_key->rsa->n) -
+ SSH_KEY_BITS_RESERVED && options.server_key_bits <
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
+ SSH_KEY_BITS_RESERVED) {
+ options.server_key_bits =
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
+ SSH_KEY_BITS_RESERVED;
+ debug("Forcing server key to %d bits to make it differ from host key.",
+ options.server_key_bits);
+ }
+ }
+
+ if (use_privsep) {
+ struct stat st;
+
+ if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
+ (S_ISDIR(st.st_mode) == 0))
+ fatal("Missing privilege separation directory: %s",
+ _PATH_PRIVSEP_CHROOT_DIR);
+
+#ifdef HAVE_CYGWIN
+ if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
+ (st.st_uid != getuid () ||
+ (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
+#else
+ if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
+#endif
+ fatal("%s must be owned by root and not group or "
+ "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
+ }
+
+ if (test_flag > 1) {
+ if (test_user != NULL && test_addr != NULL && test_host != NULL)
+ parse_server_match_config(&options, test_user,
+ test_host, test_addr);
+ dump_config(&options);
+ }
+
+ /* Configuration looks good, so exit if in test mode. */
+ if (test_flag)
+ exit(0);
+
+ /*
+ * Clear out any supplemental groups we may have inherited. This
+ * prevents inadvertent creation of files with bad modes (in the
+ * portable version at least, it's certainly possible for PAM
+ * to create a file, and we can't control the code in every
+ * module which might be used).
+ */
+ if (setgroups(0, NULL) < 0)
+ debug("setgroups() failed: %.200s", strerror(errno));
+
+ if (rexec_flag) {
+ rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
+ for (i = 0; i < rexec_argc; i++) {
+ debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
+ rexec_argv[i] = saved_argv[i];
+ }
+ rexec_argv[rexec_argc] = "-R";
+ rexec_argv[rexec_argc + 1] = NULL;
+ }
+
+ /* Ensure that umask disallows at least group and world write */
+ new_umask = umask(0077) | 0022;
+ (void) umask(new_umask);
+
+ /* Initialize the log (it is reinitialized below in case we forked). */
+ if (debug_flag && (!inetd_flag || rexeced_flag))
+ log_stderr = 1;
+ 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 || no_daemon_flag)) {
+#ifdef TIOCNOTTY
+ int fd;
+#endif /* TIOCNOTTY */
+ if (daemon(0, 0) < 0)
+ fatal("daemon() failed: %.200s", strerror(errno));
+
+ /* Disconnect from the controlling tty. */
+#ifdef TIOCNOTTY
+ 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(__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);
+
+ /* Get a connection, either from inetd or a listening TCP socket */
+ if (inetd_flag) {
+ server_accept_inetd(&sock_in, &sock_out);
+ } else {
+ platform_pre_listen();
+ server_listen();
+
+ if (options.protocol & SSH_PROTO_1)
+ generate_ephemeral_server_key();
+
+ signal(SIGHUP, sighup_handler);
+ signal(SIGCHLD, main_sigchld_handler);
+ signal(SIGTERM, sigterm_handler);
+ signal(SIGQUIT, sigterm_handler);
+
+ /*
+ * Write out the pid file after the sigterm handler
+ * is setup and the listen sockets are bound
+ */
+ if (!debug_flag) {
+ FILE *f = fopen(options.pid_file, "w");
+
+ if (f == NULL) {
+ error("Couldn't create pid file \"%s\": %s",
+ options.pid_file, strerror(errno));
+ } else {
+ fprintf(f, "%ld\n", (long) getpid());
+ fclose(f);
+ }
+ }
+
+ /* Accept a connection and return in a forked child */
+ server_accept_loop(&sock_in, &sock_out,
+ &newsock, config_s);
+ }
+
+ /* This is the child processing a new connection. */
+ setproctitle("%s", "[accepted]");
+
+ /*
+ * Create a new session and process group since the 4.4BSD
+ * setlogin() affects the entire process group. We don't
+ * want the child to be able to affect the parent.
+ */
+#if !defined(SSHD_ACQUIRES_CTTY)
+ /*
+ * If setsid is called, on some platforms sshd will later acquire a
+ * controlling terminal which will result in "could not set
+ * controlling tty" errors.
+ */
+ if (!debug_flag && !inetd_flag && setsid() < 0)
+ error("setsid: %.100s", strerror(errno));
+#endif
+
+ if (rexec_flag) {
+ int fd;
+
+ debug("rexec start in %d out %d newsock %d pipe %d sock %d",
+ sock_in, sock_out, newsock, startup_pipe, config_s[0]);
+ dup2(newsock, STDIN_FILENO);
+ dup2(STDIN_FILENO, STDOUT_FILENO);
+ if (startup_pipe == -1)
+ close(REEXEC_STARTUP_PIPE_FD);
+ else
+ dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
+
+ dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
+ close(config_s[1]);
+ if (startup_pipe != -1)
+ close(startup_pipe);
+
+ execv(rexec_argv[0], rexec_argv);
+
+ /* Reexec has failed, fall back and continue */
+ error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
+ recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
+ log_init(__progname, options.log_level,
+ options.log_facility, log_stderr);
+
+ /* Clean up fds */
+ startup_pipe = REEXEC_STARTUP_PIPE_FD;
+ close(config_s[1]);
+ close(REEXEC_CONFIG_PASS_FD);
+ newsock = sock_out = sock_in = dup(STDIN_FILENO);
+ if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
+ dup2(fd, STDIN_FILENO);
+ dup2(fd, STDOUT_FILENO);
+ if (fd > STDERR_FILENO)
+ close(fd);
+ }
+ debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
+ sock_in, sock_out, newsock, startup_pipe, config_s[0]);
+ }
+
+ /* Executed child processes don't need these. */
+ fcntl(sock_out, F_SETFD, FD_CLOEXEC);
+ fcntl(sock_in, F_SETFD, FD_CLOEXEC);
+
+ /*
+ * Disable the key regeneration alarm. We will not regenerate the
+ * key since we are no longer in a position to give it to anyone. We
+ * will not restart on SIGHUP since it no longer makes sense.
+ */
+ alarm(0);
+ signal(SIGALRM, SIG_DFL);
+ signal(SIGHUP, SIG_DFL);
+ signal(SIGTERM, SIG_DFL);
+ signal(SIGQUIT, SIG_DFL);
+ signal(SIGCHLD, SIG_DFL);
+ signal(SIGINT, SIG_DFL);
+
+ /*
+ * Register our connection. This turns encryption off because we do
+ * not have a key.
+ */
+ packet_set_connection(sock_in, sock_out);
+ packet_set_server();
+
+ /* Set SO_KEEPALIVE if requested. */
+ if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
+ setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
+ error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
+
+ if ((remote_port = get_remote_port()) < 0) {
+ debug("get_remote_port failed");
+ cleanup_exit(255);
+ }
+
+ /*
+ * We use get_canonical_hostname with usedns = 0 instead of
+ * get_remote_ipaddr here so IP options will be checked.
+ */
+ (void) get_canonical_hostname(0);
+ /*
+ * The rest of the code depends on the fact that
+ * get_remote_ipaddr() caches the remote ip, even if
+ * the socket goes away.
+ */
+ remote_ip = get_remote_ipaddr();
+
+#ifdef SSH_AUDIT_EVENTS
+ audit_connection_from(remote_ip, remote_port);
+#endif
+#ifdef LIBWRAP
+ allow_severity = options.log_facility|LOG_INFO;
+ deny_severity = options.log_facility|LOG_WARNING;
+ /* Check whether logins are denied from this host. */
+ if (packet_connection_is_on_socket()) {
+ struct request_info req;
+
+ request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
+ fromhost(&req);
+
+ if (!hosts_access(&req)) {
+ debug("Connection refused by tcp wrapper");
+ refuse(&req);
+ /* NOTREACHED */
+ fatal("libwrap refuse returns");
+ }
+ }
+#endif /* LIBWRAP */
+
+ /* Log the connection. */
+ verbose("Connection from %.500s port %d", remote_ip, remote_port);
+
+ /*
+ * We don't want to listen forever unless the other side
+ * successfully authenticates itself. So we set up an alarm which is
+ * cleared after successful authentication. A limit of zero
+ * indicates no limit. Note that we don't set the alarm in debugging
+ * mode; it is just annoying to have the server exit just when you
+ * are about to discover the bug.
+ */
+ signal(SIGALRM, grace_alarm_handler);
+ if (!debug_flag)
+ alarm(options.login_grace_time);
+
+ sshd_exchange_identification(sock_in, sock_out);
+
+ /* In inetd mode, generate ephemeral key only for proto 1 connections */
+ if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
+ generate_ephemeral_server_key();
+
+ packet_set_nonblocking();
+
+ /* allocate authentication context */
+ authctxt = xcalloc(1, sizeof(*authctxt));
+
+ authctxt->loginmsg = &loginmsg;
+
+ /* XXX global for cleanup, access from other modules */
+ the_authctxt = authctxt;
+
+ /* prepare buffer to collect messages to display to user after login */
+ buffer_init(&loginmsg);
+ auth_debug_reset();
+
+ if (use_privsep)
+ if (privsep_preauth(authctxt) == 1)
+ goto authenticated;
+
+ /* perform the key exchange */
+ /* authenticate user and start session */
+ if (compat20) {
+ do_ssh2_kex();
+ do_authentication2(authctxt);
+ } else {
+ do_ssh1_kex();
+ do_authentication(authctxt);
+ }
+ /*
+ * If we use privilege separation, the unprivileged child transfers
+ * the current keystate and exits
+ */
+ if (use_privsep) {
+ mm_send_keystate(pmonitor);
+ exit(0);
+ }
+
+ authenticated:
+ /*
+ * Cancel the alarm we set to limit the time taken for
+ * authentication.
+ */
+ alarm(0);
+ signal(SIGALRM, SIG_DFL);
+ authctxt->authenticated = 1;
+ if (startup_pipe != -1) {
+ close(startup_pipe);
+ startup_pipe = -1;
+ }
+
+#ifdef SSH_AUDIT_EVENTS
+ audit_event(SSH_AUTH_SUCCESS);
+#endif
+
+#ifdef GSSAPI
+ if (options.gss_authentication) {
+ temporarily_use_uid(authctxt->pw);
+ ssh_gssapi_storecreds();
+ restore_uid();
+ }
+#endif
+#ifdef USE_PAM
+ if (options.use_pam) {
+ do_pam_setcred(1);
+ do_pam_session();
+ }
+#endif
+
+ /*
+ * In privilege separation, we fork another child and prepare
+ * file descriptor passing.
+ */
+ if (use_privsep) {
+ privsep_postauth(authctxt);
+ /* the monitor process [priv] will not return */
+ if (!compat20)
+ destroy_sensitive_data();
+ }
+
+ packet_set_timeout(options.client_alive_interval,
+ options.client_alive_count_max);
+
+ /* Start session. */
+ do_authenticated(authctxt);
+
+ /* The connection has been terminated. */
+ packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes);
+ packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes);
+ verbose("Transferred: sent %llu, received %llu bytes",
+ (unsigned long long)obytes, (unsigned long long)ibytes);
+
+ verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
+
+#ifdef USE_PAM
+ if (options.use_pam)
+ finish_pam();
+#endif /* USE_PAM */
+
+#ifdef SSH_AUDIT_EVENTS
+ PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
+#endif
+
+ packet_close();
+
+ if (use_privsep)
+ mm_terminate();
+
+ exit(0);
+}
+
+/*
+ * Decrypt session_key_int using our private server key and private host key
+ * (key with larger modulus first).
+ */
+int
+ssh1_session_key(BIGNUM *session_key_int)
+{
+ int rsafail = 0;
+
+ if (BN_cmp(sensitive_data.server_key->rsa->n,
+ sensitive_data.ssh1_host_key->rsa->n) > 0) {
+ /* Server key has bigger modulus. */
+ if (BN_num_bits(sensitive_data.server_key->rsa->n) <
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
+ SSH_KEY_BITS_RESERVED) {
+ fatal("do_connection: %s: "
+ "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
+ get_remote_ipaddr(),
+ BN_num_bits(sensitive_data.server_key->rsa->n),
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
+ SSH_KEY_BITS_RESERVED);
+ }
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.server_key->rsa) <= 0)
+ rsafail++;
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.ssh1_host_key->rsa) <= 0)
+ rsafail++;
+ } else {
+ /* Host key has bigger modulus (or they are equal). */
+ if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
+ BN_num_bits(sensitive_data.server_key->rsa->n) +
+ SSH_KEY_BITS_RESERVED) {
+ fatal("do_connection: %s: "
+ "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
+ get_remote_ipaddr(),
+ BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
+ BN_num_bits(sensitive_data.server_key->rsa->n),
+ SSH_KEY_BITS_RESERVED);
+ }
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.ssh1_host_key->rsa) < 0)
+ rsafail++;
+ if (rsa_private_decrypt(session_key_int, session_key_int,
+ sensitive_data.server_key->rsa) < 0)
+ rsafail++;
+ }
+ return (rsafail);
+}
+/*
+ * SSH1 key exchange
+ */
+static void
+do_ssh1_kex(void)
+{
+ int i, len;
+ int rsafail = 0;
+ BIGNUM *session_key_int;
+ u_char session_key[SSH_SESSION_KEY_LENGTH];
+ u_char cookie[8];
+ u_int cipher_type, auth_mask, protocol_flags;
+
+ /*
+ * Generate check bytes that the client must send back in the user
+ * packet in order for it to be accepted; this is used to defy ip
+ * spoofing attacks. Note that this only works against somebody
+ * doing IP spoofing from a remote machine; any machine on the local
+ * network can still see outgoing packets and catch the random
+ * cookie. This only affects rhosts authentication, and this is one
+ * of the reasons why it is inherently insecure.
+ */
+ arc4random_buf(cookie, sizeof(cookie));
+
+ /*
+ * Send our public key. We include in the packet 64 bits of random
+ * data that must be matched in the reply in order to prevent IP
+ * spoofing.
+ */
+ packet_start(SSH_SMSG_PUBLIC_KEY);
+ for (i = 0; i < 8; i++)
+ packet_put_char(cookie[i]);
+
+ /* Store our public server RSA key. */
+ 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.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_mask_ssh1(0));
+
+ /* Declare supported authentication types. */
+ auth_mask = 0;
+ if (options.rhosts_rsa_authentication)
+ auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
+ if (options.rsa_authentication)
+ auth_mask |= 1 << SSH_AUTH_RSA;
+ if (options.challenge_response_authentication == 1)
+ auth_mask |= 1 << SSH_AUTH_TIS;
+ if (options.password_authentication)
+ auth_mask |= 1 << SSH_AUTH_PASSWORD;
+ packet_put_int(auth_mask);
+
+ /* Send the packet and wait for it to be sent. */
+ packet_send();
+ packet_write_wait();
+
+ 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(SSH_CMSG_SESSION_KEY);
+
+ /* Get cipher type and check whether we accept this. */
+ cipher_type = packet_get_char();
+
+ 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
+ sent earlier with the public key packet. */
+ for (i = 0; i < 8; i++)
+ if (cookie[i] != packet_get_char())
+ packet_disconnect("IP Spoofing check bytes do not match.");
+
+ debug("Encryption type: %.200s", cipher_name(cipher_type));
+
+ /* Get the encrypted integer. */
+ 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();
+
+ /* 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
+ * least significant 256 bits of the integer; the first byte of the
+ * key is in the highest bits.
+ */
+ if (!rsafail) {
+ (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
+ len = BN_num_bytes(session_key_int);
+ if (len < 0 || (u_int)len > sizeof(session_key)) {
+ error("do_ssh1_kex: 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);
+
+ derive_ssh1_session_id(
+ sensitive_data.ssh1_host_key->rsa->n,
+ sensitive_data.server_key->rsa->n,
+ cookie, session_id);
+ /*
+ * Xor the first 16 bytes of the session key with the
+ * session id.
+ */
+ 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;
+
+ logit("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. 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);
+
+ /* Set the session key. From this on all communications will be encrypted. */
+ packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
+
+ /* Destroy our copy of the session key. It is no longer needed. */
+ memset(session_key, 0, sizeof(session_key));
+
+ debug("Received session key; encryption turned on.");
+
+ /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
+ packet_start(SSH_SMSG_SUCCESS);
+ packet_send();
+ packet_write_wait();
+}
+
+/*
+ * SSH2 key exchange: diffie-hellman-group1-sha1
+ */
+static void
+do_ssh2_kex(void)
+{
+ Kex *kex;
+
+ 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;
+ }
+ if (options.compression == COMP_NONE) {
+ myproposal[PROPOSAL_COMP_ALGS_CTOS] =
+ myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
+ } else if (options.compression == COMP_DELAYED) {
+ myproposal[PROPOSAL_COMP_ALGS_CTOS] =
+ myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
+ }
+ if (options.kex_algorithms != NULL)
+ myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
+
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
+
+ /* start key exchange */
+ kex = kex_setup(myproposal);
+ kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
+ kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
+ kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
+ kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
+ kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
+ kex->server = 1;
+ kex->client_version_string=client_version_string;
+ kex->server_version_string=server_version_string;
+ kex->load_host_public_key=&get_hostkey_public_by_type;
+ kex->load_host_private_key=&get_hostkey_private_by_type;
+ kex->host_key_index=&get_hostkey_index;
+
+ xxx_kex = kex;
+
+ dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
+
+ session_id2 = kex->session_id;
+ session_id2_len = kex->session_id_len;
+
+#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("KEX done");
+}
+
+/* server specific fatal cleanup */
+void
+cleanup_exit(int i)
+{
+ if (the_authctxt)
+ do_cleanup(the_authctxt);
+#ifdef SSH_AUDIT_EVENTS
+ /* done after do_cleanup so it can cancel the PAM auth 'thread' */
+ if (!use_privsep || mm_is_monitor())
+ audit_event(SSH_CONNECTION_ABANDON);
+#endif
+ _exit(i);
+}
projects / openssh.git / blobdiff