X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/9aaf9be4b138b89bdb52bbb020084bc8f3935868..5ba55adaa243d18f3474fd9f9015b50fc58421a8:/sshd.c diff --git a/sshd.c b/sshd.c index e3903c78..a20b81cc 100644 --- a/sshd.c +++ b/sshd.c @@ -2,45 +2,75 @@ * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved - * Created: Fri Mar 17 17:09:28 1995 ylo - * This program is the ssh daemon. It listens for connections from clients, and - * performs authentication, executes use commands or shell, and forwards + * This program is the ssh daemon. It listens for connections from clients, + * and performs authentication, executes use commands or shell, and forwards * information to/from the application to the user client over an encrypted - * connection. This can also handle forwarding of X11, TCP/IP, and authentication - * agent connections. + * connection. This can also handle forwarding of X11, TCP/IP, and + * authentication agent connections. * - * SSH2 implementation, - * Copyright (c) 2000 Markus Friedl. All rights reserved. + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * SSH2 implementation: + * + * Copyright (c) 2000 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.125 2000/08/17 20:06:34 markus Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.196 2001/05/18 14:13:29 markus Exp $"); + +#include +#include +#include +#include "ssh.h" +#include "ssh1.h" +#include "ssh2.h" #include "xmalloc.h" #include "rsa.h" -#include "ssh.h" -#include "pty.h" +#include "sshpty.h" #include "packet.h" -#include "cipher.h" #include "mpaux.h" +#include "log.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" #include "buffer.h" - -#include "ssh2.h" -#include -#include -#include +#include "cipher.h" #include "kex.h" -#include -#include #include "key.h" -#include "dsa.h" - -#include "auth.h" +#include "dh.h" #include "myproposal.h" #include "authfile.h" +#include "pathnames.h" +#include "atomicio.h" +#include "canohost.h" +#include "auth.h" +#include "misc.h" +#include "dispatch.h" #ifdef LIBWRAP #include @@ -53,11 +83,17 @@ int deny_severity = LOG_WARNING; #define O_NOCTTY 0 #endif +#ifdef HAVE___PROGNAME +extern char *__progname; +#else +char *__progname; +#endif + /* Server configuration options. */ ServerOptions options; /* Name of the server configuration file. */ -char *config_file_name = SERVER_CONFIG_FILE; +char *config_file_name = _PATH_SERVER_CONFIG_FILE; /* * Flag indicating whether IPv4 or IPv6. This can be set on the command line. @@ -80,12 +116,12 @@ int debug_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; -/* argv[0] without path. */ -char *av0; - /* Saved arguments to main(). */ char **saved_argv; int saved_argc; @@ -105,6 +141,9 @@ int num_listen_socks = 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 @@ -114,37 +153,39 @@ char *server_version_string = NULL; * not very useful. Currently, memory locking is not implemented. */ struct { - RSA *private_key; /* Private part of empheral server key. */ - RSA *host_key; /* Private part of host key. */ - Key *dsa_host_key; /* Private DSA host key. */ + Key *server_key; /* ephemeral server key */ + Key *ssh1_host_key; /* ssh1 host key */ + Key **host_keys; /* all private host keys */ + int have_ssh1_key; + int have_ssh2_key; + u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; } sensitive_data; /* - * Flag indicating whether the current session key has been used. This flag - * is set whenever the key is used, and cleared when the key is regenerated. + * Flag indicating whether the RSA server key needs to be regenerated. + * Is set in the SIGALRM handler and cleared when the key is regenerated. */ -int key_used = 0; +int key_do_regen = 0; /* This is set to true when SIGHUP is received. */ int received_sighup = 0; -/* Public side of the server key. This value is regenerated regularly with - the private key. */ -RSA *public_key; - /* session identifier, used by RSA-auth */ -unsigned char session_id[16]; +u_char session_id[16]; /* same for ssh2 */ -unsigned char *session_id2 = NULL; +u_char *session_id2 = NULL; int session_id2_len = 0; /* record remote hostname or ip */ -unsigned int utmp_len = MAXHOSTNAMELEN; +u_int utmp_len = MAXHOSTNAMELEN; /* Prototypes for various functions defined later in this file. */ -void do_ssh1_kex(); -void do_ssh2_kex(); +void do_ssh1_kex(void); +void do_ssh2_kex(void); + +void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *); +void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *); /* * Close all listening sockets @@ -175,12 +216,12 @@ sighup_handler(int sig) * Restarts the server. */ void -sighup_restart() +sighup_restart(void) { log("Received SIGHUP; restarting."); close_listen_socks(); execv(saved_argv[0], saved_argv); - log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno)); + log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); exit(1); } @@ -235,35 +276,36 @@ grace_alarm_handler(int sig) * Thus there should be no concurrency control/asynchronous execution * problems. */ -/* XXX do we really want this work to be done in a signal handler ? -m */ void -key_regeneration_alarm(int sig) +generate_ephemeral_server_key(void) { - int save_errno = errno; - - /* Check if we should generate a new key. */ - if (key_used) { - /* This should really be done in the background. */ - log("Generating new %d bit RSA key.", options.server_key_bits); - - if (sensitive_data.private_key != NULL) - RSA_free(sensitive_data.private_key); - sensitive_data.private_key = RSA_new(); + u_int32_t rand = 0; + int i; - if (public_key != NULL) - RSA_free(public_key); - public_key = RSA_new(); + 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."); - rsa_generate_key(sensitive_data.private_key, public_key, - options.server_key_bits); - arc4random_stir(); - key_used = 0; - log("RSA key generation complete."); + for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { + if (i % 4 == 0) + rand = arc4random(); + sensitive_data.ssh1_cookie[i] = rand & 0xff; + rand >>= 8; } - /* Reschedule the alarm. */ - signal(SIGALRM, key_regeneration_alarm); - alarm(options.key_regeneration_time); + arc4random_stir(); +} + +void +key_regeneration_alarm(int sig) +{ + int save_errno = errno; + signal(SIGALRM, SIG_DFL); errno = save_errno; + key_do_regen = 1; } void @@ -298,20 +340,24 @@ sshd_exchange_identification(int sock_in, int sock_out) 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) + break; continue; } if (buf[i] == '\n') { - /* buf[i] == '\n' */ - buf[i + 1] = 0; + buf[i] = 0; break; } } @@ -338,6 +384,12 @@ sshd_exchange_identification(int sock_in, int sock_out) compat_datafellows(remote_version); + if (datafellows & SSH_BUG_SCANNER) { + log("scanned from %s with %s. Don't panic.", + get_remote_ipaddr(), client_version_string); + fatal_cleanup(); + } + mismatch = 0; switch(remote_major) { case 1: @@ -371,7 +423,6 @@ sshd_exchange_identification(int sock_in, int sock_out) break; } chop(server_version_string); - chop(client_version_string); debug("Local version string %.200s", server_version_string); if (mismatch) { @@ -389,18 +440,61 @@ sshd_exchange_identification(int sock_in, int sock_out) } +/* Destroy the host and server keys. They will no longer be needed. */ void destroy_sensitive_data(void) { - /* Destroy the private and public keys. They will no longer be needed. */ - if (public_key) - RSA_free(public_key); - if (sensitive_data.private_key) - RSA_free(sensitive_data.private_key); - if (sensitive_data.host_key) - RSA_free(sensitive_data.host_key); - if (sensitive_data.dsa_host_key != NULL) - key_free(sensitive_data.dsa_host_key); + int i; + + if (sensitive_data.server_key) { + key_free(sensitive_data.server_key); + sensitive_data.server_key = NULL; + } + for(i = 0; i < options.num_host_key_files; i++) { + if (sensitive_data.host_keys[i]) { + key_free(sensitive_data.host_keys[i]); + sensitive_data.host_keys[i] = NULL; + } + } + sensitive_data.ssh1_host_key = NULL; + memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); +} + +char * +list_hostkey_types(void) +{ + static char buf[1024]; + int i; + buf[0] = '\0'; + for(i = 0; i < options.num_host_key_files; i++) { + Key *key = sensitive_data.host_keys[i]; + if (key == NULL) + continue; + switch(key->type) { + case KEY_RSA: + case KEY_DSA: + strlcat(buf, key_ssh_name(key), sizeof buf); + strlcat(buf, ",", sizeof buf); + break; + } + } + i = strlen(buf); + if (i > 0 && buf[i-1] == ',') + buf[i-1] = '\0'; + debug("list_hostkey_types: %s", buf); + return buf; +} + +Key * +get_hostkey_by_type(int type) +{ + int i; + for(i = 0; i < options.num_host_key_files; i++) { + Key *key = sensitive_data.host_keys[i]; + if (key != NULL && key->type == type) + return key; + } + return NULL; } /* @@ -446,7 +540,6 @@ main(int ac, char **av) int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1; pid_t pid; socklen_t fromlen; - int silent = 0; fd_set *fdset; struct sockaddr_storage from; const char *remote_ip; @@ -458,22 +551,21 @@ main(int ac, char **av) int listen_sock, maxfd; int startup_p[2]; int startups = 0; + Key *key; + int ret, key_used = 0; + __progname = get_progname(av[0]); init_rng(); - /* Save argv[0]. */ + /* Save argv. */ saved_argc = ac; saved_argv = av; - if (strchr(av[0], '/')) - av0 = strrchr(av[0], '/') + 1; - else - av0 = av[0]; /* Initialize configuration options to their default values. */ initialize_server_options(&options); /* Parse command-line arguments. */ - while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:diqQ46")) != EOF) { + while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDeiqQ46")) != -1) { switch (opt) { case '4': IPv4or6 = AF_INET; @@ -485,14 +577,27 @@ main(int ac, char **av) config_file_name = optarg; break; case 'd': - debug_flag = 1; - options.log_level = SYSLOG_LEVEL_DEBUG; + if (0 == debug_flag) { + debug_flag = 1; + options.log_level = SYSLOG_LEVEL_DEBUG1; + } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) { + options.log_level++; + } else { + fprintf(stderr, "Too high debugging level.\n"); + exit(1); + } + break; + case 'D': + no_daemon_flag = 1; + break; + case 'e': + log_stderr = 1; break; case 'i': inetd_flag = 1; break; case 'Q': - silent = 1; + /* ignored */ break; case 'q': options.log_level = SYSLOG_LEVEL_QUIET; @@ -502,9 +607,15 @@ main(int ac, char **av) break; case 'p': options.ports_from_cmdline = 1; - if (options.num_ports >= MAX_PORTS) - fatal("too many ports.\n"); - options.ports[options.num_ports++] = atoi(optarg); + 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': options.login_grace_time = atoi(optarg); @@ -513,7 +624,11 @@ main(int ac, char **av) options.key_regeneration_time = atoi(optarg); break; case 'h': - options.host_key_file = optarg; + if (options.num_host_key_files >= MAX_HOSTKEYS) { + fprintf(stderr, "too many host keys.\n"); + exit(1); + } + options.host_key_files[options.num_host_key_files++] = optarg; break; case 'V': client_version_string = optarg; @@ -526,33 +641,37 @@ main(int ac, char **av) case '?': default: fprintf(stderr, "sshd version %s\n", SSH_VERSION); - fprintf(stderr, "Usage: %s [options]\n", av0); + fprintf(stderr, "Usage: %s [options]\n", __progname); fprintf(stderr, "Options:\n"); - fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE); - fprintf(stderr, " -d Debugging mode\n"); + fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE); + fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n"); fprintf(stderr, " -i Started from inetd\n"); + fprintf(stderr, " -D Do not fork into daemon mode\n"); fprintf(stderr, " -q Quiet (no logging)\n"); fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n"); - fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n"); + fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n"); fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); fprintf(stderr, " -h file File from which to read host key (default: %s)\n", - HOST_KEY_FILE); + _PATH_HOST_KEY_FILE); fprintf(stderr, " -u len Maximum hostname length for utmp recording\n"); fprintf(stderr, " -4 Use IPv4 only\n"); fprintf(stderr, " -6 Use IPv6 only\n"); exit(1); } } + SSLeay_add_all_algorithms(); /* * Force logging to stderr until we have loaded the private host * key (unless started from inetd) */ - log_init(av0, + log_init(__progname, options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility, - !silent && !inetd_flag); + !inetd_flag); + + seed_rng(); /* Read server configuration options from the configuration file. */ read_server_config(&options, config_file_name); @@ -568,44 +687,47 @@ main(int ac, char **av) debug("sshd version %.100s", SSH_VERSION); - sensitive_data.dsa_host_key = NULL; - sensitive_data.host_key = NULL; - - /* check if RSA support exists */ - if ((options.protocol & SSH_PROTO_1) && - rsa_alive() == 0) { - log("no RSA support in libssl and libcrypto. See ssl(8)"); - log("Disabling protocol version 1"); - options.protocol &= ~SSH_PROTO_1; - } - /* Load the RSA/DSA host key. It must have empty passphrase. */ - if (options.protocol & SSH_PROTO_1) { - Key k; - sensitive_data.host_key = RSA_new(); - k.type = KEY_RSA; - k.rsa = sensitive_data.host_key; - errno = 0; - if (!load_private_key(options.host_key_file, "", &k, NULL)) { - error("Could not load host key: %.200s: %.100s", - options.host_key_file, strerror(errno)); - log("Disabling protocol version 1"); - options.protocol &= ~SSH_PROTO_1; + /* load private host keys */ + sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*)); + for(i = 0; i < options.num_host_key_files; i++) + sensitive_data.host_keys[i] = NULL; + sensitive_data.server_key = NULL; + sensitive_data.ssh1_host_key = NULL; + sensitive_data.have_ssh1_key = 0; + sensitive_data.have_ssh2_key = 0; + + for(i = 0; i < options.num_host_key_files; i++) { + key = key_load_private(options.host_key_files[i], "", NULL); + sensitive_data.host_keys[i] = key; + if (key == NULL) { + error("Could not load host key: %s", + options.host_key_files[i]); + sensitive_data.host_keys[i] = NULL; + continue; } - k.rsa = NULL; - } - if (options.protocol & SSH_PROTO_2) { - sensitive_data.dsa_host_key = key_new(KEY_DSA); - if (!load_private_key(options.host_dsa_key_file, "", sensitive_data.dsa_host_key, NULL)) { - - error("Could not load DSA host key: %.200s", options.host_dsa_key_file); - log("Disabling protocol version 2"); - options.protocol &= ~SSH_PROTO_2; + switch(key->type){ + case KEY_RSA1: + sensitive_data.ssh1_host_key = key; + sensitive_data.have_ssh1_key = 1; + break; + case KEY_RSA: + case KEY_DSA: + sensitive_data.have_ssh2_key = 1; + break; } + debug("private host key: #%d type %d %s", i, key->type, + key_type(key)); } - if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) { - if (silent == 0) - fprintf(stderr, "sshd: no hostkeys available -- exiting.\n"); - log("sshd: no hostkeys available -- exiting.\n"); + if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { + log("Disabling protocol version 1. Could not load host key"); + options.protocol &= ~SSH_PROTO_1; + } + if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { + log("Disabling protocol version 2. Could not load host key"); + options.protocol &= ~SSH_PROTO_2; + } + if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { + log("sshd: no hostkeys available -- exiting."); exit(1); } @@ -622,27 +744,31 @@ main(int ac, char **av) * hate software patents. I dont know if this can go? Niels */ if (options.server_key_bits > - BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED && + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED && options.server_key_bits < - BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { options.server_key_bits = - BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED; + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED; debug("Forcing server key to %d bits to make it differ from host key.", options.server_key_bits); } } +#ifdef HAVE_SCO_PROTECTED_PW + (void) set_auth_parameters(ac, av); +#endif + /* Initialize the log (it is reinitialized below in case we forked). */ if (debug_flag && !inetd_flag) log_stderr = 1; - log_init(av0, options.log_level, options.log_facility, log_stderr); + log_init(__progname, options.log_level, options.log_facility, log_stderr); /* * If not in debugging mode, and not started from inetd, disconnect * from the controlling terminal, and fork. The original process * exits. */ - if (!debug_flag && !inetd_flag) { + if (!(debug_flag || inetd_flag || no_daemon_flag)) { #ifdef TIOCNOTTY int fd; #endif /* TIOCNOTTY */ @@ -651,7 +777,7 @@ main(int ac, char **av) /* Disconnect from the controlling tty. */ #ifdef TIOCNOTTY - fd = open("/dev/tty", O_RDWR | O_NOCTTY); + fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); if (fd >= 0) { (void) ioctl(fd, TIOCNOTTY, NULL); close(fd); @@ -659,10 +785,7 @@ main(int ac, char **av) #endif /* TIOCNOTTY */ } /* Reinitialize the log (because of the fork above). */ - log_init(av0, options.log_level, options.log_facility, log_stderr); - - /* Do not display messages to stdout in RSA code. */ - rsa_set_verbose(0); + log_init(__progname, options.log_level, options.log_facility, log_stderr); /* Initialize the random number generator. */ arc4random_stir(); @@ -670,12 +793,15 @@ main(int ac, char **av) /* Chdir to the root directory so that the current disk can be unmounted if desired. */ chdir("/"); + + /* ignore SIGPIPE */ + signal(SIGPIPE, SIG_IGN); /* Start listening for a socket, unless started from inetd. */ if (inetd_flag) { - 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; @@ -685,16 +811,8 @@ main(int ac, char **av) * ttyfd happens to be one of those. */ debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); - - if (options.protocol & SSH_PROTO_1) { - public_key = RSA_new(); - sensitive_data.private_key = RSA_new(); - log("Generating %d bit RSA key.", options.server_key_bits); - rsa_generate_key(sensitive_data.private_key, public_key, - options.server_key_bits); - arc4random_stir(); - log("RSA key generation complete."); - } + if (options.protocol & SSH_PROTO_1) + generate_ephemeral_server_key(); } else { for (ai = options.listen_addrs; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) @@ -736,10 +854,10 @@ main(int ac, char **av) 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; } @@ -759,32 +877,20 @@ main(int ac, char **av) if (!debug_flag) { /* - * Record our pid in /etc/sshd_pid to make it easier - * to kill the correct sshd. We don\'t want to do - * this before the bind above because the bind will + * Record our pid in /var/run/sshd.pid to make it + * easier to kill the correct sshd. We don't want to + * do this before the bind above because the bind will * fail if there already is a daemon, and this will * overwrite any old pid in the file. */ - f = fopen(options.pid_file, "w"); + f = fopen(options.pid_file, "wb"); if (f) { - fprintf(f, "%u\n", (unsigned int) getpid()); + fprintf(f, "%u\n", (u_int) getpid()); fclose(f); } } - if (options.protocol & SSH_PROTO_1) { - public_key = RSA_new(); - sensitive_data.private_key = RSA_new(); - - log("Generating %d bit RSA key.", options.server_key_bits); - rsa_generate_key(sensitive_data.private_key, public_key, - options.server_key_bits); - arc4random_stir(); - log("RSA key generation complete."); - - /* Schedule server key regeneration alarm. */ - signal(SIGALRM, key_regeneration_alarm); - alarm(options.key_regeneration_time); - } + if (options.protocol & SSH_PROTO_1) + generate_ephemeral_server_key(); /* Arrange to restart on SIGHUP. The handler needs listen_sock. */ signal(SIGHUP, sighup_handler); @@ -815,7 +921,7 @@ main(int ac, char **av) sighup_restart(); if (fdset != NULL) xfree(fdset); - fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask); + fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); fdset = (fd_set *)xmalloc(fdsetsz); memset(fdset, 0, fdsetsz); @@ -826,18 +932,24 @@ main(int ac, char **av) FD_SET(startup_pipes[i], fdset); /* Wait in select until there is a connection. */ - if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) { - if (errno != EINTR) - error("select: %.100s", strerror(errno)); - continue; + ret = select(maxfd+1, fdset, NULL, NULL, NULL); + if (ret < 0 && errno != EINTR) + error("select: %.100s", strerror(errno)); + if (key_used && key_do_regen) { + generate_ephemeral_server_key(); + key_used = 0; + key_do_regen = 0; } + if (ret < 0) + continue; + for (i = 0; i < options.max_startups; i++) if (startup_pipes[i] != -1 && FD_ISSET(startup_pipes[i], fdset)) { /* * the read end of the pipe is ready * if the child has closed the pipe - * after successfull authentication + * after successful authentication * or if the child has died */ close(startup_pipes[i]); @@ -877,7 +989,7 @@ main(int ac, char **av) startups++; break; } - + /* * Got connection. Fork a child to handle it, unless * we are in debugging mode. @@ -916,7 +1028,7 @@ main(int ac, char **av) close_listen_socks(); sock_in = newsock; sock_out = newsock; - log_init(av0, options.log_level, options.log_facility, log_stderr); + log_init(__progname, options.log_level, options.log_facility, log_stderr); break; } } @@ -930,7 +1042,13 @@ main(int ac, char **av) close(startup_p[1]); /* Mark that the key has been used (it was "given" to the child). */ - key_used = 1; + if ((options.protocol & SSH_PROTO_1) && + key_used == 0) { + /* Schedule server key regeneration alarm. */ + signal(SIGALRM, key_regeneration_alarm); + alarm(options.key_regeneration_time); + key_used = 1; + } arc4random_stir(); @@ -968,6 +1086,12 @@ main(int ac, char **av) linger.l_linger = 5; setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); + /* Set keepalives if requested. */ + if (options.keepalives && + setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, + sizeof(on)) < 0) + error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); + /* * Register our connection. This turns encryption off because we do * not have a key. @@ -983,13 +1107,13 @@ main(int ac, char **av) { struct request_info req; - request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL); + request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL); fromhost(&req); if (!hosts_access(&req)) { + refuse(&req); close(sock_in); close(sock_out); - refuse(&req); } /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */ } @@ -1011,16 +1135,17 @@ main(int ac, char **av) sshd_exchange_identification(sock_in, sock_out); /* - * Check that the connection comes from a privileged port. Rhosts- - * and Rhosts-RSA-Authentication only make sense from priviledged + * Check that the connection comes from a privileged port. + * Rhosts-Authentication only makes sense from priviledged * programs. Of course, if the intruder has root access on his local * machine, he can connect from any port. So do not use these * authentication methods from machines that you do not trust. */ if (remote_port >= IPPORT_RESERVED || remote_port < IPPORT_RESERVED / 2) { + debug("Rhosts Authentication disabled, " + "originating port not trusted."); options.rhosts_authentication = 0; - options.rhosts_rsa_authentication = 0; } #ifdef KRB4 if (!packet_connection_is_ipv4() && @@ -1029,6 +1154,13 @@ main(int ac, char **av) options.kerberos_authentication = 0; } #endif /* KRB4 */ +#ifdef AFS + /* If machine has AFS, set process authentication group. */ + if (k_hasafs()) { + k_setpag(); + k_unlog(); + } +#endif /* AFS */ packet_set_nonblocking(); @@ -1063,14 +1195,15 @@ main(int ac, char **av) * SSH1 key exchange */ void -do_ssh1_kex() +do_ssh1_kex(void) { int i, len; int plen, slen; + int rsafail = 0; BIGNUM *session_key_int; - unsigned char session_key[SSH_SESSION_KEY_LENGTH]; - unsigned char cookie[8]; - unsigned int cipher_type, auth_mask, protocol_flags; + u_char session_key[SSH_SESSION_KEY_LENGTH]; + u_char cookie[8]; + u_int cipher_type, auth_mask, protocol_flags; u_int32_t rand = 0; /* @@ -1099,20 +1232,20 @@ do_ssh1_kex() packet_put_char(cookie[i]); /* Store our public server RSA key. */ - packet_put_int(BN_num_bits(public_key->n)); - packet_put_bignum(public_key->e); - packet_put_bignum(public_key->n); + packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); + packet_put_bignum(sensitive_data.server_key->rsa->e); + packet_put_bignum(sensitive_data.server_key->rsa->n); /* Store our public host RSA key. */ - packet_put_int(BN_num_bits(sensitive_data.host_key->n)); - packet_put_bignum(sensitive_data.host_key->e); - packet_put_bignum(sensitive_data.host_key->n); + packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); + packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); + packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); /* Put protocol flags. */ packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); /* Declare which ciphers we support. */ - packet_put_int(cipher_mask1()); + packet_put_int(cipher_mask_ssh1(0)); /* Declare supported authentication types. */ auth_mask = 0; @@ -1132,10 +1265,8 @@ do_ssh1_kex() if (options.afs_token_passing) auth_mask |= 1 << SSH_PASS_AFS_TOKEN; #endif -#ifdef SKEY - if (options.skey_authentication == 1) + if (options.challenge_response_authentication == 1) auth_mask |= 1 << SSH_AUTH_TIS; -#endif if (options.password_authentication) auth_mask |= 1 << SSH_AUTH_PASSWORD; packet_put_int(auth_mask); @@ -1144,8 +1275,9 @@ do_ssh1_kex() packet_send(); packet_write_wait(); - debug("Sent %d bit public key and %d bit host key.", - BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n)); + debug("Sent %d bit server key and %d bit host key.", + BN_num_bits(sensitive_data.server_key->rsa->n), + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); /* Read clients reply (cipher type and session key). */ packet_read_expect(&plen, SSH_CMSG_SESSION_KEY); @@ -1153,7 +1285,7 @@ do_ssh1_kex() /* Get cipher type and check whether we accept this. */ cipher_type = packet_get_char(); - if (!(cipher_mask() & (1 << cipher_type))) + if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) packet_disconnect("Warning: client selects unsupported cipher."); /* Get check bytes from the packet. These must match those we @@ -1177,64 +1309,95 @@ do_ssh1_kex() * Decrypt it using our private server key and private host key (key * with larger modulus first). */ - if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) { - /* Private key has bigger modulus. */ - if (BN_num_bits(sensitive_data.private_key->n) < - BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { - fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", - get_remote_ipaddr(), - BN_num_bits(sensitive_data.private_key->n), - BN_num_bits(sensitive_data.host_key->n), - SSH_KEY_BITS_RESERVED); + if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { + /* Server key has bigger modulus. */ + if (BN_num_bits(sensitive_data.server_key->rsa->n) < + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { + fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", + get_remote_ipaddr(), + BN_num_bits(sensitive_data.server_key->rsa->n), + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), + SSH_KEY_BITS_RESERVED); } - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.private_key); - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.host_key); + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.server_key->rsa) <= 0) + rsafail++; + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.ssh1_host_key->rsa) <= 0) + rsafail++; } else { /* Host key has bigger modulus (or they are equal). */ - if (BN_num_bits(sensitive_data.host_key->n) < - BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) { - fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d", - get_remote_ipaddr(), - BN_num_bits(sensitive_data.host_key->n), - BN_num_bits(sensitive_data.private_key->n), - SSH_KEY_BITS_RESERVED); + if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < + BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { + fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", + get_remote_ipaddr(), + BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), + BN_num_bits(sensitive_data.server_key->rsa->n), + SSH_KEY_BITS_RESERVED); } - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.host_key); - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.private_key); + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.ssh1_host_key->rsa) < 0) + rsafail++; + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.server_key->rsa) < 0) + rsafail++; } - - compute_session_id(session_id, cookie, - sensitive_data.host_key->n, - sensitive_data.private_key->n); - - /* Destroy the private and public keys. They will no longer be needed. */ - destroy_sensitive_data(); - /* * Extract session key from the decrypted integer. The key is in the * least significant 256 bits of the integer; the first byte of the * key is in the highest bits. */ - BN_mask_bits(session_key_int, sizeof(session_key) * 8); - len = BN_num_bytes(session_key_int); - if (len < 0 || len > sizeof(session_key)) - fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d", - get_remote_ipaddr(), - len, sizeof(session_key)); - memset(session_key, 0, sizeof(session_key)); - BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); + if (!rsafail) { + BN_mask_bits(session_key_int, sizeof(session_key) * 8); + len = BN_num_bytes(session_key_int); + if (len < 0 || len > sizeof(session_key)) { + error("do_connection: bad session key len from %s: " + "session_key_int %d > sizeof(session_key) %lu", + get_remote_ipaddr(), len, (u_long)sizeof(session_key)); + rsafail++; + } else { + memset(session_key, 0, sizeof(session_key)); + BN_bn2bin(session_key_int, + session_key + sizeof(session_key) - len); + + compute_session_id(session_id, cookie, + sensitive_data.ssh1_host_key->rsa->n, + sensitive_data.server_key->rsa->n); + /* + * Xor the first 16 bytes of the session key with the + * session id. + */ + for (i = 0; i < 16; i++) + session_key[i] ^= session_id[i]; + } + } + if (rsafail) { + int bytes = BN_num_bytes(session_key_int); + char *buf = xmalloc(bytes); + MD5_CTX md; + + log("do_connection: generating a fake encryption key"); + BN_bn2bin(session_key_int, buf); + MD5_Init(&md); + MD5_Update(&md, buf, bytes); + MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); + MD5_Final(session_key, &md); + MD5_Init(&md); + MD5_Update(&md, session_key, 16); + MD5_Update(&md, buf, bytes); + MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); + MD5_Final(session_key + 16, &md); + memset(buf, 0, bytes); + xfree(buf); + for (i = 0; i < 16; i++) + session_id[i] = session_key[i] ^ session_key[i + 16]; + } + /* Destroy the private and public keys. They will no longer be needed. */ + destroy_sensitive_data(); /* Destroy the decrypted integer. It is no longer needed. */ BN_clear_free(session_key_int); - /* Xor the first 16 bytes of the session key with the session id. */ - for (i = 0; i < 16; i++) - session_key[i] ^= session_id[i]; - /* Set the session key. From this on all communications will be encrypted. */ packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); @@ -1253,152 +1416,38 @@ do_ssh1_kex() * SSH2 key exchange: diffie-hellman-group1-sha1 */ void -do_ssh2_kex() +do_ssh2_kex(void) { - Buffer *server_kexinit; - Buffer *client_kexinit; - int payload_len, dlen; - int slen; - unsigned int klen, kout; - unsigned char *signature = NULL; - unsigned char *server_host_key_blob = NULL; - unsigned int sbloblen; - DH *dh; - BIGNUM *dh_client_pub = 0; - BIGNUM *shared_secret = 0; - int i; - unsigned char *kbuf; - unsigned char *hash; Kex *kex; - char *cprop[PROPOSAL_MAX]; - -/* KEXINIT */ if (options.ciphers != NULL) { myproposal[PROPOSAL_ENC_ALGS_CTOS] = myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; } - server_kexinit = kex_init(myproposal); - client_kexinit = xmalloc(sizeof(*client_kexinit)); - buffer_init(client_kexinit); - - /* 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]); - -/* KEXDH */ - - 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= "); - bignum_print(dh_client_pub); - fprintf(stderr, "\n"); - debug("bits %d", BN_num_bits(dh_client_pub)); -#endif - - /* generate DH key */ - dh = dh_new_group1(); /* XXX depends on 'kex' */ - -#ifdef DEBUG_KEXDH - fprintf(stderr, "\np= "); - bignum_print(dh->p); - fprintf(stderr, "\ng= "); - bignum_print(dh->g); - fprintf(stderr, "\npub= "); - bignum_print(dh->pub_key); - fprintf(stderr, "\n"); -#endif - if (!dh_pub_is_valid(dh, dh_client_pub)) - packet_disconnect("bad client public DH value"); - - klen = DH_size(dh); - kbuf = xmalloc(klen); - kout = DH_compute_key(kbuf, dh_client_pub, dh); - -#ifdef DEBUG_KEXDH - debug("shared secret: len %d/%d", klen, kout); - fprintf(stderr, "shared secret == "); - for (i = 0; i< kout; i++) - fprintf(stderr, "%02x", (kbuf[i])&0xff); - fprintf(stderr, "\n"); -#endif - shared_secret = BN_new(); - - BN_bin2bn(kbuf, kout, shared_secret); - memset(kbuf, 0, klen); - xfree(kbuf); - - /* XXX precompute? */ - dsa_make_key_blob(sensitive_data.dsa_host_key, &server_host_key_blob, &sbloblen); - - /* calc H */ /* XXX depends on 'kex' */ - hash = kex_hash( - 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); -#ifdef DEBUG_KEXDH - fprintf(stderr, "hash == "); - for (i = 0; i< 20; i++) - fprintf(stderr, "%02x", (hash[i])&0xff); - fprintf(stderr, "\n"); -#endif - /* save session id := H */ - /* XXX hashlen depends on KEX */ - session_id2_len = 20; - session_id2 = xmalloc(session_id2_len); - memcpy(session_id2, hash, session_id2_len); - - /* sign H */ - /* XXX hashlen depends on KEX */ - dsa_sign(sensitive_data.dsa_host_key, &signature, &slen, hash, 20); - - destroy_sensitive_data(); - - /* send server hostkey, DH pubkey 'f' and singed H */ - packet_start(SSH2_MSG_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(); + 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(); - kex_derive_keys(kex, hash, shared_secret); - packet_set_kex(kex); + /* 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; - /* have keys, free DH */ - DH_free(dh); + xxx_kex = kex; - 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 */ @@ -1407,5 +1456,5 @@ do_ssh2_kex() packet_send(); packet_write_wait(); #endif - debug("done: KEX2."); + debug("KEX done"); }