X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/43e48848f0212b19f6b1a01f01c41d32d6e38b2f..278a05ad21a7e1729abc503ff0a1a1085b2da7f9:/sshd.c diff --git a/sshd.c b/sshd.c index 5062d376..4bd0cbe8 100644 --- a/sshd.c +++ b/sshd.c @@ -2,28 +2,70 @@ * 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. + * + * 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 1.91 2000/03/09 19:31:47 markus Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.136 2000/12/05 16:47:28 todd Exp $"); #include "xmalloc.h" #include "rsa.h" #include "ssh.h" #include "pty.h" #include "packet.h" -#include "buffer.h" -#include "cipher.h" #include "mpaux.h" #include "servconf.h" #include "uidswap.h" #include "compat.h" +#include "buffer.h" + +#include "ssh2.h" +#include +#include +#include +#include "kex.h" +#include +#include +#include "key.h" +#include "dh.h" + +#include "auth.h" +#include "myproposal.h" +#include "authfile.h" #ifdef LIBWRAP #include @@ -36,8 +78,11 @@ int deny_severity = LOG_WARNING; #define O_NOCTTY 0 #endif -/* Local Xauthority file. */ -static char *xauthfile = NULL; +#ifdef HAVE___PROGNAME +extern char *__progname; +#else +char *__progname; +#endif /* Server configuration options. */ ServerOptions options; @@ -45,7 +90,7 @@ ServerOptions options; /* Name of the server configuration file. */ char *config_file_name = SERVER_CONFIG_FILE; -/* +/* * Flag indicating whether IPv4 or IPv6. This can be set on the command line. * Default value is AF_UNSPEC means both IPv4 and IPv6. */ @@ -66,6 +111,9 @@ 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; @@ -74,6 +122,7 @@ char *av0; /* Saved arguments to main(). */ char **saved_argv; +int saved_argc; /* * The sockets that the server is listening; this is used in the SIGHUP @@ -88,21 +137,7 @@ int num_listen_socks = 0; * sshd will skip the version-number exchange */ char *client_version_string = NULL; - -/* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ -int no_port_forwarding_flag = 0; -int no_agent_forwarding_flag = 0; -int no_x11_forwarding_flag = 0; -int no_pty_flag = 0; - -/* RSA authentication "command=" option. */ -char *forced_command = NULL; - -/* RSA authentication "environment=" options. */ -struct envstring *custom_environment = NULL; - -/* Session id for the current session. */ -unsigned char session_id[16]; +char *server_version_string = NULL; /* * Any really sensitive data in the application is contained in this @@ -113,8 +148,11 @@ unsigned char session_id[16]; * not very useful. Currently, memory locking is not implemented. */ struct { - RSA *private_key; /* Private part of server key. */ - RSA *host_key; /* Private part of host key. */ + Key *server_key; /* empheral server key */ + Key *ssh1_host_key; /* ssh1 host key */ + Key **host_keys; /* all private host keys */ + int have_ssh1_key; + int have_ssh2_key; } sensitive_data; /* @@ -126,47 +164,22 @@ int key_used = 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]; + +/* same for ssh2 */ +unsigned char *session_id2 = NULL; +int session_id2_len = 0; + +/* record remote hostname or ip */ +unsigned int utmp_len = MAXHOSTNAMELEN; /* Prototypes for various functions defined later in this file. */ -void do_ssh_kex(); -void do_authentication(); -void do_authloop(struct passwd * pw); -void do_fake_authloop(char *user); -void do_authenticated(struct passwd * pw); -void do_exec_pty(const char *command, int ptyfd, int ttyfd, - const char *ttyname, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data); -void do_exec_no_pty(const char *command, struct passwd * pw, - const char *display, const char *auth_proto, - const char *auth_data); -void do_child(const char *command, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data, const char *ttyname); +void do_ssh1_kex(); +void do_ssh2_kex(); -/* - * Remove local Xauthority file. - */ -void -xauthfile_cleanup_proc(void *ignore) -{ - debug("xauthfile_cleanup_proc called"); - - if (xauthfile != NULL) { - char *p; - unlink(xauthfile); - p = strrchr(xauthfile, '/'); - if (p != NULL) { - *p = '\0'; - rmdir(xauthfile); - } - xfree(xauthfile); - xauthfile = NULL; - } -} +void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *); +void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *); /* * Close all listening sockets @@ -185,7 +198,7 @@ close_listen_socks(void) * the effect is to reread the configuration file (and to regenerate * the server key). */ -void +void sighup_handler(int sig) { received_sighup = 1; @@ -196,7 +209,7 @@ sighup_handler(int sig) * Called from the main program after receiving SIGHUP. * Restarts the server. */ -void +void sighup_restart() { log("Received SIGHUP; restarting."); @@ -211,11 +224,12 @@ sighup_restart() * These close the listen socket; not closing it seems to cause "Address * already in use" problems on some machines, which is inconvenient. */ -void +void sigterm_handler(int sig) { log("Received signal %d; terminating.", sig); close_listen_socks(); + unlink(options.pid_file); exit(255); } @@ -223,7 +237,7 @@ sigterm_handler(int sig) * SIGCHLD handler. This is called whenever a child dies. This will then * reap any zombies left by exited c. */ -void +void main_sigchld_handler(int sig) { int save_errno = errno; @@ -239,7 +253,7 @@ main_sigchld_handler(int sig) /* * Signal handler for the alarm after the login grace period has expired. */ -void +void grace_alarm_handler(int sig) { /* Close the connection. */ @@ -249,35 +263,6 @@ grace_alarm_handler(int sig) fatal("Timeout before authentication for %s.", get_remote_ipaddr()); } -/* - * convert ssh auth msg type into description - */ -char * -get_authname(int type) -{ - static char buf[1024]; - switch (type) { - case SSH_CMSG_AUTH_PASSWORD: - return "password"; - case SSH_CMSG_AUTH_RSA: - return "rsa"; - case SSH_CMSG_AUTH_RHOSTS_RSA: - return "rhosts-rsa"; - case SSH_CMSG_AUTH_RHOSTS: - return "rhosts"; -#ifdef KRB4 - case SSH_CMSG_AUTH_KERBEROS: - return "kerberos"; -#endif -#ifdef SKEY - case SSH_CMSG_AUTH_TIS_RESPONSE: - return "s/key"; -#endif - } - snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); - return buf; -} - /* * Signal handler for the key regeneration alarm. Note that this * alarm only occurs in the daemon waiting for connections, and it does not @@ -285,7 +270,19 @@ get_authname(int type) * Thus there should be no concurrency control/asynchronous execution * problems. */ -void +/* XXX do we really want this work to be done in a signal handler ? -m */ +void +generate_empheral_server_key(void) +{ + log("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "", + options.server_key_bits); + if (sensitive_data.server_key != NULL) + key_free(sensitive_data.server_key); + sensitive_data.server_key = key_generate(KEY_RSA1, options.server_key_bits); + arc4random_stir(); + log("RSA key generation complete."); +} +void key_regeneration_alarm(int sig) { int save_errno = errno; @@ -293,21 +290,8 @@ key_regeneration_alarm(int sig) /* 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(); - - if (public_key != NULL) - RSA_free(public_key); - public_key = RSA_new(); - - rsa_generate_key(sensitive_data.private_key, public_key, - options.server_key_bits); - arc4random_stir(); + generate_empheral_server_key(); key_used = 0; - log("RSA key generation complete."); } /* Reschedule the alarm. */ signal(SIGALRM, key_regeneration_alarm); @@ -315,6 +299,254 @@ key_regeneration_alarm(int sig) errno = save_errno; } +void +sshd_exchange_identification(int sock_in, int sock_out) +{ + int i, mismatch; + int remote_major, remote_minor; + int major, minor; + char *s; + 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; + } else { + major = PROTOCOL_MAJOR_1; + minor = PROTOCOL_MINOR_1; + } + snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); + server_version_string = xstrdup(buf); + + if (client_version_string == NULL) { + /* Send our protocol version identification. */ + if (atomicio(write, sock_out, server_version_string, strlen(server_version_string)) + != strlen(server_version_string)) { + log("Could not write ident string to %s.", get_remote_ipaddr()); + fatal_cleanup(); + } + + /* Read other side\'s version identification. */ + 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()); + fatal_cleanup(); + } + if (buf[i] == '\r') { + buf[i] = '\n'; + buf[i + 1] = 0; + /* Kludge for F-Secure Macintosh < 1.0.2 */ + if (i == 12 && + strncmp(buf, "SSH-1.5-W1.0", 12) == 0) + break; + continue; + } + if (buf[i] == '\n') { + /* buf[i] == '\n' */ + buf[i + 1] = 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(write, sock_out, s, strlen(s)); + close(sock_in); + close(sock_out); + log("Bad protocol version identification '%.100s' from %s", + client_version_string, get_remote_ipaddr()); + fatal_cleanup(); + } + debug("Client protocol version %d.%d; client software version %.100s", + remote_major, remote_minor, remote_version); + + compat_datafellows(remote_version); + + 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); + chop(client_version_string); + debug("Local version string %.200s", server_version_string); + + if (mismatch) { + s = "Protocol major versions differ.\n"; + (void) atomicio(write, sock_out, s, strlen(s)); + close(sock_in); + close(sock_out); + log("Protocol major versions differ for %s: %.200s vs. %.200s", + get_remote_ipaddr(), + server_version_string, client_version_string); + fatal_cleanup(); + } + if (compat20) + packet_set_ssh2_format(); +} + + +/* 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; + } + } + sensitive_data.ssh1_host_key = NULL; +} +Key * +load_private_key_autodetect(const char *filename) +{ + struct stat st; + int type; + Key *public, *private; + + if (stat(filename, &st) < 0) { + perror(filename); + return NULL; + } + /* + * try to load the public key. right now this only works for RSA1, + * since SSH2 keys are fully encrypted + */ + type = KEY_RSA1; + public = key_new(type); + if (!load_public_key(filename, public, NULL)) { + /* ok, so we will assume this is 'some' key */ + type = KEY_UNSPEC; + } + key_free(public); + + /* Ok, try key with empty passphrase */ + private = key_new(type); + if (load_private_key(filename, "", private, NULL)) { + debug("load_private_key_autodetect: type %d %s", + private->type, key_type(private)); + return private; + } + key_free(private); + return NULL; +} + +char * +list_hostkey_types(void) +{ + static char buf[1024]; + int i; + buf[0] = '\0'; + for(i = 0; i < options.num_host_key_files; i++) { + Key *key = sensitive_data.host_keys[i]; + if (key == NULL) + continue; + switch(key->type) { + case KEY_RSA: + case KEY_DSA: + strlcat(buf, key_ssh_name(key), sizeof buf); + strlcat(buf, ",", sizeof buf); + break; + } + } + i = strlen(buf); + if (i > 0 && buf[i-1] == ',') + buf[i-1] = '\0'; + debug("list_hostkey_types: %s", buf); + return buf; +} + +Key * +get_hostkey_by_type(int type) +{ + int i; + for(i = 0; i < options.num_host_key_files; i++) { + Key *key = sensitive_data.host_keys[i]; + if (key != NULL && key->type == type) + return key; + } + return NULL; +} + +/* + * returns 1 if connection should be dropped, 0 otherwise. + * dropping starts at connection #max_startups_begin with a probability + * of (max_startups_rate/100). the probability increases linearly until + * all connections are dropped for startups > max_startups + */ +int +drop_connection(int startups) +{ + double p, r; + + if (startups < options.max_startups_begin) + return 0; + if (startups >= options.max_startups) + return 1; + if (options.max_startups_rate == 100) + return 1; + + p = 100 - options.max_startups_rate; + p *= startups - options.max_startups_begin; + p /= (double) (options.max_startups - options.max_startups_begin); + p += options.max_startups_rate; + p /= 100.0; + r = arc4random() / (double) UINT_MAX; + + debug("drop_connection: p %g, r %g", p, r); + return (r < p) ? 1 : 0; +} + +int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */ +int startup_pipe; /* in child */ + /* * Main program for the daemon. */ @@ -323,24 +555,27 @@ main(int ac, char **av) { extern char *optarg; extern int optind; - int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1; + int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1; + pid_t pid; socklen_t fromlen; - int remote_major, remote_minor; - int silentrsa = 0; + int silent = 0; fd_set *fdset; struct sockaddr_storage from; - char buf[100]; /* Must not be larger than remote_version. */ - char remote_version[100]; /* Must be at least as big as buf. */ const char *remote_ip; int remote_port; - char *comment; FILE *f; struct linger linger; struct addrinfo *ai; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; int listen_sock, maxfd; + int startup_p[2]; + int startups = 0; + + __progname = get_progname(av[0]); + init_rng(); /* Save argv[0]. */ + saved_argc = ac; saved_argv = av; if (strchr(av[0], '/')) av0 = strrchr(av[0], '/') + 1; @@ -351,7 +586,7 @@ main(int ac, char **av) initialize_server_options(&options); /* Parse command-line arguments. */ - while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) { + while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != EOF) { switch (opt) { case '4': IPv4or6 = AF_INET; @@ -363,14 +598,24 @@ 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 'i': inetd_flag = 1; break; case 'Q': - silentrsa = 1; + silent = 1; break; case 'q': options.log_level = SYSLOG_LEVEL_QUIET; @@ -380,8 +625,10 @@ main(int ac, char **av) break; case 'p': options.ports_from_cmdline = 1; - if (options.num_ports >= MAX_PORTS) - fatal("too many ports.\n"); + if (options.num_ports >= MAX_PORTS) { + fprintf(stderr, "too many ports.\n"); + exit(1); + } options.ports[options.num_ports++] = atoi(optarg); break; case 'g': @@ -391,20 +638,27 @@ 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; /* only makes sense with inetd_flag, i.e. no listen() */ inetd_flag = 1; break; + case 'u': + utmp_len = atoi(optarg); + break; case '?': default: fprintf(stderr, "sshd version %s\n", SSH_VERSION); fprintf(stderr, "Usage: %s [options]\n", av0); fprintf(stderr, "Options:\n"); fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE); - fprintf(stderr, " -d Debugging mode\n"); + fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n"); fprintf(stderr, " -i Started from inetd\n"); fprintf(stderr, " -q Quiet (no logging)\n"); fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); @@ -413,6 +667,7 @@ main(int ac, char **av) fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); fprintf(stderr, " -h file File from which to read host key (default: %s)\n", HOST_KEY_FILE); + fprintf(stderr, " -u len Maximum hostname length for utmp recording\n"); fprintf(stderr, " -4 Use IPv4 only\n"); fprintf(stderr, " -6 Use IPv6 only\n"); exit(1); @@ -426,27 +681,14 @@ main(int ac, char **av) log_init(av0, options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility, - !inetd_flag); + !silent && !inetd_flag); - /* check if RSA support exists */ - if (rsa_alive() == 0) { - if (silentrsa == 0) - printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n"); - log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)"); - exit(1); - } /* Read server configuration options from the configuration file. */ read_server_config(&options, config_file_name); /* Fill in default values for those options not explicitly set. */ fill_default_server_options(&options); - /* Check certain values for sanity. */ - if (options.server_key_bits < 512 || - options.server_key_bits > 32768) { - fprintf(stderr, "Bad server key size.\n"); - exit(1); - } /* Check that there are no remaining arguments. */ if (optind < ac) { fprintf(stderr, "Extra argument %s.\n", av[optind]); @@ -455,27 +697,85 @@ main(int ac, char **av) debug("sshd version %.100s", SSH_VERSION); - sensitive_data.host_key = RSA_new(); - errno = 0; - /* Load the host key. It must have empty passphrase. */ - if (!load_private_key(options.host_key_file, "", - sensitive_data.host_key, &comment)) { - error("Could not load host key: %.200s: %.100s", - options.host_key_file, strerror(errno)); + /* load private host keys */ + sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*)); + sensitive_data.server_key = NULL; + sensitive_data.ssh1_host_key = NULL; + sensitive_data.have_ssh1_key = 0; + sensitive_data.have_ssh2_key = 0; + + for(i = 0; i < options.num_host_key_files; i++) { + Key *key = load_private_key_autodetect(options.host_key_files[i]); + if (key == NULL) { + error("Could not load host key: %.200s: %.100s", + options.host_key_files[i], strerror(errno)); + 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: + sensitive_data.have_ssh2_key = 1; + break; + } + sensitive_data.host_keys[i] = key; + } + if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { + log("Disabling protocol version 1. Could not load host key"); + options.protocol &= ~SSH_PROTO_1; + } + if ((options.protocol & SSH_PROTO_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)) { + if (silent == 0) + fprintf(stderr, "sshd: no hostkeys available -- exiting.\n"); + log("sshd: no hostkeys available -- exiting.\n"); exit(1); } - xfree(comment); - /* Initialize the log (it is reinitialized below in case we - forked). */ + /* Check certain values for sanity. */ + if (options.protocol & SSH_PROTO_1) { + if (options.server_key_bits < 512 || + options.server_key_bits > 32768) { + fprintf(stderr, "Bad server key size.\n"); + exit(1); + } + /* + * Check that server and host key lengths differ sufficiently. This + * is necessary to make double encryption work with rsaref. Oh, I + * hate software patents. I dont know if this can go? Niels + */ + if (options.server_key_bits > + BN_num_bits(sensitive_data.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); + } + } + +#ifdef HAVE_SCO_PROTECTED_PW + (void) set_auth_parameters(ac, av); +#endif + + /* Initialize the log (it is reinitialized below in case we forked). */ if (debug_flag && !inetd_flag) log_stderr = 1; log_init(av0, options.log_level, options.log_facility, log_stderr); - /* If not in debugging mode, and not started from inetd, - disconnect from the controlling terminal, and fork. The - original process exits. */ - if (!debug_flag && !inetd_flag) { + /* + * 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 */ @@ -494,21 +794,6 @@ main(int ac, char **av) /* Reinitialize the log (because of the fork above). */ log_init(av0, options.log_level, options.log_facility, log_stderr); - /* Check that server and host key lengths differ sufficiently. - This is necessary to make double encryption work with rsaref. - Oh, I hate software patents. I dont know if this can go? Niels */ - if (options.server_key_bits > - BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED && - options.server_key_bits < - BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { - options.server_key_bits = - BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED; - debug("Forcing server key to %d bits to make it differ from host key.", - options.server_key_bits); - } - /* Do not display messages to stdout in RSA code. */ - rsa_set_verbose(0); - /* Initialize the random number generator. */ arc4random_stir(); @@ -516,9 +801,6 @@ main(int ac, char **av) unmounted if desired. */ chdir("/"); - /* Close connection cleanly after attack. */ - cipher_attack_detected = packet_disconnect; - /* Start listening for a socket, unless started from inetd. */ if (inetd_flag) { int s1, s2; @@ -526,19 +808,15 @@ main(int ac, char **av) s2 = dup(s1); sock_in = dup(0); sock_out = dup(1); - /* We intentionally do not close the descriptors 0, 1, and 2 - as our code for setting the descriptors won\'t work - if ttyfd happens to be one of those. */ + startup_pipe = -1; + /* + * We intentionally do not close the descriptors 0, 1, and 2 + * as our code for setting the descriptors won\'t work if + * ttyfd happens to be one of those. + */ debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); - - public_key = RSA_new(); - sensitive_data.private_key = RSA_new(); - - 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_empheral_server_key(); } else { for (ai = options.listen_addrs; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) @@ -603,34 +881,29 @@ 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(SSH_DAEMON_PID_FILE, "w"); + f = fopen(options.pid_file, "wb"); if (f) { fprintf(f, "%u\n", (unsigned int) getpid()); fclose(f); } } + if (options.protocol & SSH_PROTO_1) { + generate_empheral_server_key(); - 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); + /* Schedule server key regeneration alarm. */ + signal(SIGALRM, key_regeneration_alarm); + alarm(options.key_regeneration_time); + } /* Arrange to restart on SIGHUP. The handler needs listen_sock. */ signal(SIGHUP, sighup_handler); + signal(SIGTERM, sigterm_handler); signal(SIGQUIT, sigterm_handler); @@ -638,12 +911,15 @@ main(int ac, char **av) signal(SIGCHLD, main_sigchld_handler); /* setup fd set for listen */ + fdset = NULL; maxfd = 0; for (i = 0; i < num_listen_socks; i++) if (listen_socks[i] > maxfd) maxfd = listen_socks[i]; - fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask); - fdset = (fd_set *)xmalloc(fdsetsz); + /* pipes connected to unauthenticated childs */ + startup_pipes = xmalloc(options.max_startups * sizeof(int)); + for (i = 0; i < options.max_startups; i++) + startup_pipes[i] = -1; /* * Stay listening for connections until the system crashes or @@ -652,80 +928,130 @@ main(int ac, char **av) for (;;) { if (received_sighup) sighup_restart(); - /* Wait in select until there is a connection. */ + if (fdset != NULL) + xfree(fdset); + fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask); + fdset = (fd_set *)xmalloc(fdsetsz); memset(fdset, 0, fdsetsz); + for (i = 0; i < num_listen_socks; i++) FD_SET(listen_socks[i], fdset); + for (i = 0; i < options.max_startups; i++) + if (startup_pipes[i] != -1) + FD_SET(startup_pipes[i], fdset); + + /* Wait in select until there is a connection. */ if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) { if (errno != EINTR) error("select: %.100s", strerror(errno)); continue; } + for (i = 0; i < options.max_startups; i++) + if (startup_pipes[i] != -1 && + FD_ISSET(startup_pipes[i], fdset)) { + /* + * the read end of the pipe is ready + * if the child has closed the pipe + * after successfull authentication + * or if the child has died + */ + close(startup_pipes[i]); + startup_pipes[i] = -1; + startups--; + } for (i = 0; i < num_listen_socks; i++) { if (!FD_ISSET(listen_socks[i], fdset)) continue; - fromlen = sizeof(from); - newsock = accept(listen_socks[i], (struct sockaddr *)&from, - &fromlen); - if (newsock < 0) { - if (errno != EINTR && errno != EWOULDBLOCK) - error("accept: %.100s", strerror(errno)); - continue; - } - if (fcntl(newsock, F_SETFL, 0) < 0) { - error("newsock del O_NONBLOCK: %s", strerror(errno)); - continue; - } - /* - * Got connection. Fork a child to handle it, unless - * we are in debugging mode. - */ - if (debug_flag) { - /* - * In debugging mode. Close the listening - * socket, and start processing the - * connection without forking. - */ - debug("Server will not fork when running in debugging mode."); - close_listen_socks(); - sock_in = newsock; - sock_out = newsock; - pid = getpid(); - break; - } else { + fromlen = sizeof(from); + newsock = accept(listen_socks[i], (struct sockaddr *)&from, + &fromlen); + if (newsock < 0) { + if (errno != EINTR && errno != EWOULDBLOCK) + error("accept: %.100s", strerror(errno)); + continue; + } + if (fcntl(newsock, F_SETFL, 0) < 0) { + error("newsock del O_NONBLOCK: %s", strerror(errno)); + continue; + } + if (drop_connection(startups) == 1) { + debug("drop connection #%d", startups); + close(newsock); + continue; + } + if (pipe(startup_p) == -1) { + close(newsock); + continue; + } + + for (j = 0; j < options.max_startups; j++) + if (startup_pipes[j] == -1) { + startup_pipes[j] = startup_p[0]; + if (maxfd < startup_p[0]) + maxfd = startup_p[0]; + startups++; + break; + } + /* - * Normal production daemon. Fork, and have - * the child process the connection. The - * parent continues listening. + * Got connection. Fork a child to handle it, unless + * we are in debugging mode. */ - if ((pid = fork()) == 0) { + if (debug_flag) { /* - * Child. Close the listening socket, and start using the - * accepted socket. Reinitialize logging (since our pid has - * changed). We break out of the loop to handle the connection. + * In debugging mode. Close the listening + * socket, and start processing the + * connection without forking. */ + debug("Server will not fork when running in debugging mode."); close_listen_socks(); sock_in = newsock; sock_out = newsock; - log_init(av0, options.log_level, options.log_facility, log_stderr); + startup_pipe = -1; + pid = getpid(); break; + } else { + /* + * Normal production daemon. Fork, and have + * the child process the connection. The + * parent continues listening. + */ + if ((pid = fork()) == 0) { + /* + * Child. Close the listening and max_startup + * sockets. Start using the accepted socket. + * Reinitialize logging (since our pid has + * changed). We break out of the loop to handle + * the connection. + */ + startup_pipe = startup_p[1]; + for (j = 0; j < options.max_startups; j++) + if (startup_pipes[j] != -1) + close(startup_pipes[j]); + close_listen_socks(); + sock_in = newsock; + sock_out = newsock; + log_init(av0, options.log_level, options.log_facility, log_stderr); + break; + } } - } - /* Parent. Stay in the loop. */ - if (pid < 0) - error("fork: %.100s", strerror(errno)); - else - debug("Forked child %d.", pid); + /* Parent. Stay in the loop. */ + if (pid < 0) + error("fork: %.100s", strerror(errno)); + else + debug("Forked child %d.", pid); + + close(startup_p[1]); - /* Mark that the key has been used (it was "given" to the child). */ - key_used = 1; + /* Mark that the key has been used (it was "given" to the child). */ + key_used = 1; - arc4random_stir(); + arc4random_stir(); - /* Close the new socket (the child is now taking care of it). */ - close(newsock); - } /* for (i = 0; i < num_listen_socks; i++) */ + /* Close the new socket (the child is now taking care of it). */ + close(newsock); + } /* child process check (or debug mode) */ if (num_listen_socks < 0) break; @@ -745,6 +1071,7 @@ main(int ac, char **av) signal(SIGTERM, SIG_DFL); signal(SIGQUIT, SIG_DFL); signal(SIGCHLD, SIG_DFL); + signal(SIGINT, SIG_DFL); /* * Set socket options for the connection. We want the socket to @@ -797,73 +1124,7 @@ main(int ac, char **av) if (!debug_flag) alarm(options.login_grace_time); - if (client_version_string != NULL) { - /* we are exec'ed by sshd2, so skip exchange of protocol version */ - strlcpy(buf, client_version_string, sizeof(buf)); - } else { - /* Send our protocol version identification. */ - snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", - PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); - if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) { - log("Could not write ident string to %s.", remote_ip); - fatal_cleanup(); - } - - /* Read other side\'s version identification. */ - for (i = 0; i < sizeof(buf) - 1; i++) { - if (read(sock_in, &buf[i], 1) != 1) { - log("Did not receive ident string from %s.", remote_ip); - fatal_cleanup(); - } - if (buf[i] == '\r') { - buf[i] = '\n'; - buf[i + 1] = 0; - break; - } - if (buf[i] == '\n') { - /* buf[i] == '\n' */ - buf[i + 1] = 0; - break; - } - } - buf[sizeof(buf) - 1] = 0; - } - - /* - * Check that the versions match. In future this might accept - * several versions and set appropriate flags to handle them. - */ - if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, - remote_version) != 3) { - char *s = "Protocol mismatch.\n"; - - (void) atomicio(write, sock_out, s, strlen(s)); - close(sock_in); - close(sock_out); - log("Bad protocol version identification '%.100s' from %s", - buf, remote_ip); - fatal_cleanup(); - } - debug("Client protocol version %d.%d; client software version %.100s", - remote_major, remote_minor, remote_version); - if (remote_major != PROTOCOL_MAJOR) { - char *s = "Protocol major versions differ.\n"; - - (void) atomicio(write, sock_out, s, strlen(s)); - close(sock_in); - close(sock_out); - log("Protocol major versions differ for %s: %d vs. %d", - remote_ip, PROTOCOL_MAJOR, remote_major); - fatal_cleanup(); - } - /* Check that the client has sufficiently high software version. */ - if (remote_major == 1 && remote_minor < 3) - packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version."); - - if (remote_major == 1 && remote_minor == 3) { - /* note that this disables agent-forwarding */ - enable_compat13(); - } + 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 @@ -873,6 +1134,8 @@ main(int ac, char **av) */ if (remote_port >= IPPORT_RESERVED || remote_port < IPPORT_RESERVED / 2) { + debug("Rhosts Authentication methods disabled, " + "originating port not trusted."); options.rhosts_authentication = 0; options.rhosts_rsa_authentication = 0; } @@ -887,10 +1150,14 @@ main(int ac, char **av) packet_set_nonblocking(); /* perform the key exchange */ - do_ssh_kex(); - /* authenticate user and start session */ - do_authentication(); + if (compat20) { + do_ssh2_kex(); + do_authentication2(); + } else { + do_ssh1_kex(); + do_authentication(); + } #ifdef KRB4 /* Cleanup user's ticket cache file. */ @@ -898,10 +1165,6 @@ main(int ac, char **av) (void) dest_tkt(); #endif /* KRB4 */ - /* Cleanup user's local Xauthority file. */ - if (xauthfile) - xauthfile_cleanup_proc(NULL); - /* The connection has been terminated. */ verbose("Closing connection to %.100s", remote_ip); @@ -917,7 +1180,7 @@ main(int ac, char **av) * SSH1 key exchange */ void -do_ssh_kex() +do_ssh1_kex() { int i, len; int plen, slen; @@ -953,20 +1216,20 @@ do_ssh_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_mask()); + packet_put_int(cipher_mask_ssh1(0)); /* Declare supported authentication types. */ auth_mask = 0; @@ -998,8 +1261,9 @@ do_ssh_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); @@ -1007,7 +1271,7 @@ do_ssh_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 @@ -1031,44 +1295,42 @@ do_ssh_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) { + if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->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_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); + sensitive_data.server_key->rsa); rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.host_key); + sensitive_data.ssh1_host_key->rsa); } 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); + sensitive_data.ssh1_host_key->rsa); rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.private_key); + sensitive_data.server_key->rsa); } compute_session_id(session_id, cookie, - sensitive_data.host_key->n, - sensitive_data.private_key->n); + sensitive_data.ssh1_host_key->rsa->n, + sensitive_data.server_key->rsa->n); /* Destroy the private and public keys. They will no longer be needed. */ - RSA_free(public_key); - RSA_free(sensitive_data.private_key); - RSA_free(sensitive_data.host_key); + destroy_sensitive_data(); /* * Extract session key from the decrypted integer. The key is in the @@ -1079,8 +1341,8 @@ do_ssh_kex() 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)); + 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); @@ -1105,1578 +1367,335 @@ do_ssh_kex() packet_write_wait(); } - /* - * Check if the user is allowed to log in via ssh. If user is listed in - * DenyUsers or user's primary group is listed in DenyGroups, false will - * be returned. If AllowUsers isn't empty and user isn't listed there, or - * if AllowGroups isn't empty and user isn't listed there, false will be - * returned. - * If the user's shell is not executable, false will be returned. - * Otherwise true is returned. + * SSH2 key exchange: diffie-hellman-group1-sha1 */ -static int -allowed_user(struct passwd * pw) +void +do_ssh2_kex() { - struct stat st; - struct group *grp; + Buffer *server_kexinit; + Buffer *client_kexinit; + int payload_len; int i; -#ifdef WITH_AIXAUTHENTICATE - char *loginmsg; -#endif /* WITH_AIXAUTHENTICATE */ + Kex *kex; + char *cprop[PROPOSAL_MAX]; - /* Shouldn't be called if pw is NULL, but better safe than sorry... */ - if (!pw) - return 0; +/* KEXINIT */ - /* deny if shell does not exists or is not executable */ - if (stat(pw->pw_shell, &st) != 0) - return 0; - if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)))) - return 0; - - /* Return false if user is listed in DenyUsers */ - if (options.num_deny_users > 0) { - if (!pw->pw_name) - return 0; - for (i = 0; i < options.num_deny_users; i++) - if (match_pattern(pw->pw_name, options.deny_users[i])) - return 0; + if (options.ciphers != NULL) { + myproposal[PROPOSAL_ENC_ALGS_CTOS] = + myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; } - /* Return false if AllowUsers isn't empty and user isn't listed there */ - if (options.num_allow_users > 0) { - if (!pw->pw_name) - return 0; - for (i = 0; i < options.num_allow_users; i++) - if (match_pattern(pw->pw_name, options.allow_users[i])) - break; - /* i < options.num_allow_users iff we break for loop */ - if (i >= options.num_allow_users) - return 0; + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); + + 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]); + + switch (kex->kex_type) { + case DH_GRP1_SHA1: + ssh_dh1_server(kex, client_kexinit, server_kexinit); + break; + case DH_GEX_SHA1: + ssh_dhgex_server(kex, client_kexinit, server_kexinit); + break; + default: + fatal("Unsupported key exchange %d", kex->kex_type); } - /* Get the primary group name if we need it. Return false if it fails */ - if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { - grp = getgrgid(pw->pw_gid); - if (!grp) - return 0; - - /* Return false if user's group is listed in DenyGroups */ - if (options.num_deny_groups > 0) { - if (!grp->gr_name) - return 0; - for (i = 0; i < options.num_deny_groups; i++) - if (match_pattern(grp->gr_name, options.deny_groups[i])) - return 0; - } - /* - * Return false if AllowGroups isn't empty and user's group - * isn't listed there - */ - if (options.num_allow_groups > 0) { - if (!grp->gr_name) - return 0; - for (i = 0; i < options.num_allow_groups; i++) - if (match_pattern(grp->gr_name, options.allow_groups[i])) - break; - /* i < options.num_allow_groups iff we break for - loop */ - if (i >= options.num_allow_groups) - return 0; - } - } - -#ifdef WITH_AIXAUTHENTICATE - if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0) - return 0; -#endif /* WITH_AIXAUTHENTICATE */ - /* We found no reason not to let this user try to log on... */ - return 1; -} - -/* - * Performs authentication of an incoming connection. Session key has already - * been exchanged and encryption is enabled. - */ -void -do_authentication() -{ - struct passwd *pw, pwcopy; - int plen, ulen; - char *user; - - /* Get the name of the user that we wish to log in as. */ - packet_read_expect(&plen, SSH_CMSG_USER); - - /* Get the user name. */ - user = packet_get_string(&ulen); - packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); - - setproctitle("%s", user); - -#ifdef WITH_AIXAUTHENTICATE - char *loginmsg; -#endif /* WITH_AIXAUTHENTICATE */ - -#ifdef AFS - /* If machine has AFS, set process authentication group. */ - if (k_hasafs()) { - k_setpag(); - k_unlog(); - } -#endif /* AFS */ - - /* Verify that the user is a valid user. */ - pw = getpwnam(user); - if (!pw || !allowed_user(pw)) - do_fake_authloop(user); - xfree(user); - - /* Take a copy of the returned structure. */ - memset(&pwcopy, 0, sizeof(pwcopy)); - pwcopy.pw_name = xstrdup(pw->pw_name); - pwcopy.pw_passwd = xstrdup(pw->pw_passwd); - pwcopy.pw_uid = pw->pw_uid; - pwcopy.pw_gid = pw->pw_gid; - pwcopy.pw_dir = xstrdup(pw->pw_dir); - pwcopy.pw_shell = xstrdup(pw->pw_shell); - pw = &pwcopy; - -#ifdef USE_PAM - start_pam(pw); -#endif - - /* - * If we are not running as root, the user must have the same uid as - * the server. - */ - if (getuid() != 0 && pw->pw_uid != getuid()) - packet_disconnect("Cannot change user when server not running as root."); - - debug("Attempting authentication for %.100s.", pw->pw_name); - - /* If the user has no password, accept authentication immediately. */ - if (options.password_authentication && -#ifdef KRB4 - (!options.kerberos_authentication || options.kerberos_or_local_passwd) && -#endif /* KRB4 */ -#ifdef USE_PAM - auth_pam_password(pw, "")) { -#else /* USE_PAM */ - auth_password(pw, "")) { -#endif /* USE_PAM */ - /* Authentication with empty password succeeded. */ - log("Login for user %s from %.100s, accepted without authentication.", - pw->pw_name, get_remote_ipaddr()); - } else { - /* Loop until the user has been authenticated or the - connection is closed, do_authloop() returns only if - authentication is successfull */ - do_authloop(pw); - } - - /* The user has been authenticated and accepted. */ -#ifdef WITH_AIXAUTHENTICATE - loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg); -#endif /* WITH_AIXAUTHENTICATE */ - packet_start(SSH_SMSG_SUCCESS); + debug("send SSH2_MSG_NEWKEYS."); + packet_start(SSH2_MSG_NEWKEYS); packet_send(); packet_write_wait(); + debug("done: send SSH2_MSG_NEWKEYS."); - /* Perform session preparation. */ - do_authenticated(pw); -} + debug("Wait SSH2_MSG_NEWKEYS."); + packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS); + debug("GOT SSH2_MSG_NEWKEYS."); -#define AUTH_FAIL_MAX 6 -#define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) -#define AUTH_FAIL_MSG "Too many authentication failures for %.100s" - -/* - * read packets and try to authenticate local user *pw. - * return if authentication is successfull - */ -void -do_authloop(struct passwd * pw) -{ - int attempt = 0; - unsigned int bits; - BIGNUM *client_host_key_e, *client_host_key_n; - BIGNUM *n; - char *client_user = NULL, *password = NULL; - char user[1024]; - int plen, dlen, nlen, ulen, elen; - int type = 0; - void (*authlog) (const char *fmt,...) = verbose; - - /* Indicate that authentication is needed. */ - packet_start(SSH_SMSG_FAILURE); +#ifdef DEBUG_KEXDH + /* send 1st encrypted/maced/compressed message */ + packet_start(SSH2_MSG_IGNORE); + packet_put_cstring("markus"); packet_send(); packet_write_wait(); - - for (attempt = 1;; attempt++) { - int authenticated = 0; - strlcpy(user, "", sizeof user); - - /* Get a packet from the client. */ - type = packet_read(&plen); - - /* Process the packet. */ - switch (type) { -#ifdef AFS - case SSH_CMSG_HAVE_KERBEROS_TGT: - if (!options.kerberos_tgt_passing) { - /* packet_get_all(); */ - verbose("Kerberos tgt passing disabled."); - break; - } else { - /* Accept Kerberos tgt. */ - char *tgt = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - if (!auth_kerberos_tgt(pw, tgt)) - verbose("Kerberos tgt REFUSED for %s", pw->pw_name); - xfree(tgt); - } - continue; - - case SSH_CMSG_HAVE_AFS_TOKEN: - if (!options.afs_token_passing || !k_hasafs()) { - /* packet_get_all(); */ - verbose("AFS token passing disabled."); - break; - } else { - /* Accept AFS token. */ - char *token_string = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - if (!auth_afs_token(pw, token_string)) - verbose("AFS token REFUSED for %s", pw->pw_name); - xfree(token_string); - } - continue; -#endif /* AFS */ -#ifdef KRB4 - case SSH_CMSG_AUTH_KERBEROS: - if (!options.kerberos_authentication) { - /* packet_get_all(); */ - verbose("Kerberos authentication disabled."); - break; - } else { - /* Try Kerberos v4 authentication. */ - KTEXT_ST auth; - char *tkt_user = NULL; - char *kdata = packet_get_string((unsigned int *) &auth.length); - packet_integrity_check(plen, 4 + auth.length, type); - - if (auth.length < MAX_KTXT_LEN) - memcpy(auth.dat, kdata, auth.length); - xfree(kdata); - - authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); - - if (authenticated) { - snprintf(user, sizeof user, " tktuser %s", tkt_user); - xfree(tkt_user); - } - } - break; -#endif /* KRB4 */ - - case SSH_CMSG_AUTH_RHOSTS: - if (!options.rhosts_authentication) { - verbose("Rhosts authentication disabled."); - break; - } - /* - * Get client user name. Note that we just have to - * trust the client; this is one reason why rhosts - * authentication is insecure. (Another is - * IP-spoofing on a local network.) - */ - client_user = packet_get_string(&ulen); - packet_integrity_check(plen, 4 + ulen, type); - - /* Try to authenticate using /etc/hosts.equiv and - .rhosts. */ - authenticated = auth_rhosts(pw, client_user); - - snprintf(user, sizeof user, " ruser %s", client_user); - break; - - case SSH_CMSG_AUTH_RHOSTS_RSA: - if (!options.rhosts_rsa_authentication) { - verbose("Rhosts with RSA authentication disabled."); - break; - } - /* - * Get client user name. Note that we just have to - * trust the client; root on the client machine can - * claim to be any user. - */ - client_user = packet_get_string(&ulen); - - /* Get the client host key. */ - client_host_key_e = BN_new(); - client_host_key_n = BN_new(); - bits = packet_get_int(); - packet_get_bignum(client_host_key_e, &elen); - packet_get_bignum(client_host_key_n, &nlen); - - if (bits != BN_num_bits(client_host_key_n)) - error("Warning: keysize mismatch for client_host_key: " - "actual %d, announced %d", BN_num_bits(client_host_key_n), bits); - packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); - - authenticated = auth_rhosts_rsa(pw, client_user, - client_host_key_e, client_host_key_n); - BN_clear_free(client_host_key_e); - BN_clear_free(client_host_key_n); - - snprintf(user, sizeof user, " ruser %s", client_user); - break; - - case SSH_CMSG_AUTH_RSA: - if (!options.rsa_authentication) { - verbose("RSA authentication disabled."); - break; - } - /* RSA authentication requested. */ - n = BN_new(); - packet_get_bignum(n, &nlen); - packet_integrity_check(plen, nlen, type); - authenticated = auth_rsa(pw, n); - BN_clear_free(n); - break; - - case SSH_CMSG_AUTH_PASSWORD: - if (!options.password_authentication) { - verbose("Password authentication disabled."); - break; - } - /* - * Read user password. It is in plain text, but was - * transmitted over the encrypted channel so it is - * not visible to an outside observer. - */ - password = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - -#ifdef USE_PAM - /* Do PAM auth with password */ - authenticated = auth_pam_password(pw, password); -#else /* USE_PAM */ - /* Try authentication with the password. */ - authenticated = auth_password(pw, password); -#endif /* USE_PAM */ - memset(password, 0, strlen(password)); - xfree(password); - break; - -#ifdef SKEY - case SSH_CMSG_AUTH_TIS: - debug("rcvd SSH_CMSG_AUTH_TIS"); - if (options.skey_authentication == 1) { - char *skeyinfo = skey_keyinfo(pw->pw_name); - if (skeyinfo == NULL) { - debug("generating fake skeyinfo for %.100s.", pw->pw_name); - skeyinfo = skey_fake_keyinfo(pw->pw_name); - } - if (skeyinfo != NULL) { - /* we send our s/key- in tis-challenge messages */ - debug("sending challenge '%s'", skeyinfo); - packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); - packet_put_string(skeyinfo, strlen(skeyinfo)); - packet_send(); - packet_write_wait(); - continue; - } - } - break; - case SSH_CMSG_AUTH_TIS_RESPONSE: - debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); - if (options.skey_authentication == 1) { - char *response = packet_get_string(&dlen); - debug("skey response == '%s'", response); - packet_integrity_check(plen, 4 + dlen, type); - authenticated = (skey_haskey(pw->pw_name) == 0 && - skey_passcheck(pw->pw_name, response) != -1); - xfree(response); - } - break; -#else - case SSH_CMSG_AUTH_TIS: - /* TIS Authentication is unsupported */ - log("TIS authentication unsupported."); - break; #endif - default: - /* - * Any unknown messages will be ignored (and failure - * returned) during authentication. - */ - log("Unknown message during authentication: type %d", type); - break; - } - - /* - * Check if the user is logging in as root and root logins - * are disallowed. - * Note that root login is allowed for forced commands. - */ - if (authenticated && pw->pw_uid == 0 && !options.permit_root_login) { - if (forced_command) { - log("Root login accepted for forced command."); - } else { - authenticated = 0; - log("ROOT LOGIN REFUSED FROM %.200s", - get_canonical_hostname()); - } - } - - /* Raise logging level */ - if (authenticated || - attempt == AUTH_FAIL_LOG || - type == SSH_CMSG_AUTH_PASSWORD) - authlog = log; - - authlog("%s %s for %.200s from %.200s port %d%s", - authenticated ? "Accepted" : "Failed", - get_authname(type), - pw->pw_uid == 0 ? "ROOT" : pw->pw_name, - get_remote_ipaddr(), - get_remote_port(), - user); - -#ifdef USE_PAM - if (authenticated) { - if (!do_pam_account(pw->pw_name, client_user)) { - if (client_user != NULL) { - xfree(client_user); - client_user = NULL; - } - do_fake_authloop(pw->pw_name); - } - return; - } -#else /* USE_PAM */ - if (authenticated) { - return; - } -#endif /* USE_PAM */ - - if (client_user != NULL) { - xfree(client_user); - client_user = NULL; - } - - if (attempt > AUTH_FAIL_MAX) - packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); - - /* Send a message indicating that the authentication attempt failed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - } + debug("done: KEX2."); } /* - * The user does not exist or access is denied, - * but fake indication that authentication is needed. + * SSH2 key exchange */ + +/* diffie-hellman-group1-sha1 */ + void -do_fake_authloop(char *user) +ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit) { - int attempt = 0; - - log("Faking authloop for illegal user %.200s from %.200s port %d", - user, - get_remote_ipaddr(), - get_remote_port()); +#ifdef DEBUG_KEXDH + int i; +#endif + int payload_len, dlen; + int slen; + unsigned char *signature = NULL; + unsigned char *server_host_key_blob = NULL; + unsigned int sbloblen; + unsigned int klen, kout; + unsigned char *kbuf; + unsigned char *hash; + BIGNUM *shared_secret = 0; + DH *dh; + BIGNUM *dh_client_pub = 0; + Key *hostkey; + + hostkey = get_hostkey_by_type(kex->hostkey_type); + if (hostkey == NULL) + fatal("Unsupported hostkey type %d", kex->hostkey_type); + +/* 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= "); + BN_print_fp(stderr, dh_client_pub); + fprintf(stderr, "\n"); + debug("bits %d", BN_num_bits(dh_client_pub)); +#endif - /* Indicate that authentication is needed. */ - packet_start(SSH_SMSG_FAILURE); + /* generate DH key */ + dh = dh_new_group1(); /* XXX depends on 'kex' */ + +#ifdef DEBUG_KEXDH + fprintf(stderr, "\np= "); + BN_print_fp(stderr, dh->p); + fprintf(stderr, "\ng= "); + bn_print(dh->g); + fprintf(stderr, "\npub= "); + BN_print_fp(stderr, dh->pub_key); + fprintf(stderr, "\n"); + DHparams_print_fp(stderr, dh); +#endif + if (!dh_pub_is_valid(dh, dh_client_pub)) + packet_disconnect("bad client public DH value"); + + klen = DH_size(dh); + kbuf = xmalloc(klen); + kout = DH_compute_key(kbuf, dh_client_pub, dh); + +#ifdef DEBUG_KEXDH + debug("shared secret: len %d/%d", klen, kout); + fprintf(stderr, "shared secret == "); + for (i = 0; i< kout; i++) + fprintf(stderr, "%02x", (kbuf[i])&0xff); + fprintf(stderr, "\n"); +#endif + shared_secret = BN_new(); + + BN_bin2bn(kbuf, kout, shared_secret); + memset(kbuf, 0, klen); + xfree(kbuf); + + /* XXX precompute? */ + key_to_blob(hostkey, &server_host_key_blob, &sbloblen); + + /* calc H */ /* XXX depends on 'kex' */ + hash = kex_hash( + client_version_string, + server_version_string, + buffer_ptr(client_kexinit), buffer_len(client_kexinit), + buffer_ptr(server_kexinit), buffer_len(server_kexinit), + (char *)server_host_key_blob, sbloblen, + dh_client_pub, + dh->pub_key, + shared_secret + ); + buffer_free(client_kexinit); + buffer_free(server_kexinit); + xfree(client_kexinit); + xfree(server_kexinit); +#ifdef DEBUG_KEXDH + fprintf(stderr, "hash == "); + for (i = 0; i< 20; i++) + fprintf(stderr, "%02x", (hash[i])&0xff); + fprintf(stderr, "\n"); +#endif + /* save session id := H */ + /* XXX hashlen depends on KEX */ + session_id2_len = 20; + session_id2 = xmalloc(session_id2_len); + memcpy(session_id2, hash, session_id2_len); + + /* sign H */ + /* XXX hashlen depends on KEX */ + key_sign(hostkey, &signature, &slen, hash, 20); + + destroy_sensitive_data(); + + /* send server hostkey, DH pubkey 'f' and singed H */ + packet_start(SSH2_MSG_KEXDH_REPLY); + packet_put_string((char *)server_host_key_blob, sbloblen); + packet_put_bignum2(dh->pub_key); /* f */ + packet_put_string((char *)signature, slen); packet_send(); + xfree(signature); + xfree(server_host_key_blob); packet_write_wait(); - /* - * Keep reading packets, and always respond with a failure. This is - * to avoid disclosing whether such a user really exists. - */ - for (attempt = 1;; attempt++) { - /* Read a packet. This will not return if the client disconnects. */ - int plen; -#ifndef SKEY - (void)packet_read(&plen); -#else /* SKEY */ - int type = packet_read(&plen); - int dlen; - char *password, *skeyinfo; - /* Try to send a fake s/key challenge. */ - if (options.skey_authentication == 1 && - (skeyinfo = skey_fake_keyinfo(user)) != NULL) { - password = NULL; - if (type == SSH_CMSG_AUTH_TIS) { - packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); - packet_put_string(skeyinfo, strlen(skeyinfo)); - packet_send(); - packet_write_wait(); - continue; - } else if (type == SSH_CMSG_AUTH_PASSWORD && - options.password_authentication && - (password = packet_get_string(&dlen)) != NULL && - dlen == 5 && - strncasecmp(password, "s/key", 5) == 0 ) { - packet_send_debug(skeyinfo); - } - if (password != NULL) - xfree(password); - } -#endif - if (attempt > AUTH_FAIL_MAX) - packet_disconnect(AUTH_FAIL_MSG, user); - - /* - * Send failure. This should be indistinguishable from a - * failed authentication. - */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); -#ifdef WITH_AIXAUTHENTICATE - if (strncmp(get_authname(type),"password", - strlen(get_authname(type))) == 0) - loginfailed(pw->pw_name,get_canonical_hostname(),"ssh"); -#endif /* WITH_AIXAUTHENTICATE */ - } - /* NOTREACHED */ - abort(); -} - -struct pty_cleanup_context { - const char *ttyname; - int pid; -}; - -/* - * Function to perform cleanup if we get aborted abnormally (e.g., due to a - * dropped connection). - */ -void -pty_cleanup_proc(void *context) -{ - struct pty_cleanup_context *cu = context; - - debug("pty_cleanup_proc called"); - - /* Record that the user has logged out. */ - record_logout(cu->pid, cu->ttyname); - - /* Release the pseudo-tty. */ - pty_release(cu->ttyname); -} - -/* simple cleanup: chown tty slave back to root */ -static void -pty_release_proc(void *tty) -{ - char *ttyname = tty; - pty_release(ttyname); -} - -/* - * Prepares for an interactive session. This is called after the user has - * been successfully authenticated. During this message exchange, pseudo - * terminals are allocated, X11, TCP/IP, and authentication agent forwardings - * are requested, etc. - */ -void -do_authenticated(struct passwd * pw) -{ - int type; - int compression_level = 0, enable_compression_after_reply = 0; - int have_pty = 0, ptyfd = -1, ttyfd = -1; - int row, col, xpixel, ypixel, screen; - char ttyname[64]; - char *command, *term = NULL, *display = NULL, *proto = NULL, *data = NULL; - int n_bytes; - - /* - * Cancel the alarm we set to limit the time taken for - * authentication. - */ - alarm(0); - - /* - * Inform the channel mechanism that we are the server side and that - * the client may request to connect to any port at all. (The user - * could do it anyway, and we wouldn\'t know what is permitted except - * by the client telling us, so we can equally well trust the client - * not to request anything bogus.) - */ - if (!no_port_forwarding_flag) - channel_permit_all_opens(); - - /* - * We stay in this loop until the client requests to execute a shell - * or a command. - */ - while (1) { - int plen, dlen; - - /* Get a packet from the client. */ - type = packet_read(&plen); - - /* Process the packet. */ - switch (type) { - case SSH_CMSG_REQUEST_COMPRESSION: - packet_integrity_check(plen, 4, type); - compression_level = packet_get_int(); - if (compression_level < 1 || compression_level > 9) { - packet_send_debug("Received illegal compression level %d.", - compression_level); - goto fail; - } - /* Enable compression after we have responded with SUCCESS. */ - enable_compression_after_reply = 1; - break; - - case SSH_CMSG_REQUEST_PTY: - if (no_pty_flag) { - debug("Allocating a pty not permitted for this authentication."); - goto fail; - } - if (have_pty) - packet_disconnect("Protocol error: you already have a pty."); - - debug("Allocating pty."); - - /* Allocate a pty and open it. */ - if (!pty_allocate(&ptyfd, &ttyfd, ttyname, - sizeof(ttyname))) { - error("Failed to allocate pty."); - goto fail; - } - fatal_add_cleanup(pty_release_proc, (void *)ttyname); - pty_setowner(pw, ttyname); - - /* Get TERM from the packet. Note that the value may be of arbitrary length. */ - term = packet_get_string(&dlen); - packet_integrity_check(dlen, strlen(term), type); - - /* Remaining bytes */ - n_bytes = plen - (4 + dlen + 4 * 4); - - if (strcmp(term, "") == 0) { - xfree(term); - term = NULL; - } - - /* Get window size from the packet. */ - row = packet_get_int(); - col = packet_get_int(); - xpixel = packet_get_int(); - ypixel = packet_get_int(); - pty_change_window_size(ptyfd, row, col, xpixel, ypixel); - - /* Get tty modes from the packet. */ - tty_parse_modes(ttyfd, &n_bytes); - packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); - - /* Indicate that we now have a pty. */ - have_pty = 1; - break; - - case SSH_CMSG_X11_REQUEST_FORWARDING: - if (!options.x11_forwarding) { - packet_send_debug("X11 forwarding disabled in server configuration file."); - goto fail; - } -#ifdef XAUTH_PATH - if (no_x11_forwarding_flag) { - packet_send_debug("X11 forwarding not permitted for this authentication."); - goto fail; - } - debug("Received request for X11 forwarding with auth spoofing."); - if (display) - packet_disconnect("Protocol error: X11 display already set."); - { - int proto_len, data_len; - proto = packet_get_string(&proto_len); - data = packet_get_string(&data_len); - packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); - } - if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) - screen = packet_get_int(); - else - screen = 0; - display = x11_create_display_inet(screen, options.x11_display_offset); - if (!display) - goto fail; - - /* Setup to always have a local .Xauthority. */ - xauthfile = xmalloc(MAXPATHLEN); - strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); - temporarily_use_uid(pw->pw_uid); - if (mkdtemp(xauthfile) == NULL) { - restore_uid(); - error("private X11 dir: mkdtemp %s failed: %s", - xauthfile, strerror(errno)); - xfree(xauthfile); - xauthfile = NULL; - goto fail; - } - strlcat(xauthfile, "/cookies", MAXPATHLEN); - open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600); - restore_uid(); - fatal_add_cleanup(xauthfile_cleanup_proc, NULL); - break; -#else /* XAUTH_PATH */ - packet_send_debug("No xauth program; cannot forward with spoofing."); - goto fail; -#endif /* XAUTH_PATH */ - - case SSH_CMSG_AGENT_REQUEST_FORWARDING: - if (no_agent_forwarding_flag || compat13) { - debug("Authentication agent forwarding not permitted for this authentication."); - goto fail; - } - debug("Received authentication agent forwarding request."); - auth_input_request_forwarding(pw); - break; - - case SSH_CMSG_PORT_FORWARD_REQUEST: - if (no_port_forwarding_flag) { - debug("Port forwarding not permitted for this authentication."); - goto fail; - } - debug("Received TCP/IP port forwarding request."); - channel_input_port_forward_request(pw->pw_uid == 0); - break; - - case SSH_CMSG_MAX_PACKET_SIZE: - if (packet_set_maxsize(packet_get_int()) < 0) - goto fail; - break; - - case SSH_CMSG_EXEC_SHELL: - /* Set interactive/non-interactive mode. */ - packet_set_interactive(have_pty || display != NULL, - options.keepalives); - - if (forced_command != NULL) - goto do_forced_command; - debug("Forking shell."); - packet_integrity_check(plen, 0, type); - if (have_pty) - do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); - else - do_exec_no_pty(NULL, pw, display, proto, data); - return; - - case SSH_CMSG_EXEC_CMD: - /* Set interactive/non-interactive mode. */ - packet_set_interactive(have_pty || display != NULL, - options.keepalives); - - if (forced_command != NULL) - goto do_forced_command; - /* Get command from the packet. */ - { - int dlen; - command = packet_get_string(&dlen); - debug("Executing command '%.500s'", command); - packet_integrity_check(plen, 4 + dlen, type); - } - if (have_pty) - do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); - else - do_exec_no_pty(command, pw, display, proto, data); - xfree(command); - return; - - default: - /* - * Any unknown messages in this phase are ignored, - * and a failure message is returned. - */ - log("Unknown packet type received after authentication: %d", type); - goto fail; - } - - /* The request was successfully processed. */ - packet_start(SSH_SMSG_SUCCESS); - packet_send(); - packet_write_wait(); + kex_derive_keys(kex, hash, shared_secret); + packet_set_kex(kex); - /* Enable compression now that we have replied if appropriate. */ - if (enable_compression_after_reply) { - enable_compression_after_reply = 0; - packet_start_compression(compression_level); - } - continue; - -fail: - /* The request failed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - continue; - -do_forced_command: - /* - * There is a forced command specified for this login. - * Execute it. - */ - debug("Executing forced command: %.900s", forced_command); - if (have_pty) - do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); - else - do_exec_no_pty(forced_command, pw, display, proto, data); - return; - } + /* have keys, free DH */ + DH_free(dh); } -/* - * This is called to fork and execute a command when we have no tty. This - * will call do_child from the child, and server_loop from the parent after - * setting up file descriptors and such. - */ -void -do_exec_no_pty(const char *command, struct passwd * pw, - const char *display, const char *auth_proto, - const char *auth_data) -{ - int pid; - -#ifdef USE_PIPES - int pin[2], pout[2], perr[2]; - /* Allocate pipes for communicating with the program. */ - if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) - packet_disconnect("Could not create pipes: %.100s", - strerror(errno)); -#else /* USE_PIPES */ - int inout[2], err[2]; - /* Uses socket pairs to communicate with the program. */ - if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || - socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) - packet_disconnect("Could not create socket pairs: %.100s", - strerror(errno)); -#endif /* USE_PIPES */ - - setproctitle("%s@notty", pw->pw_name); - -#ifdef USE_PAM - do_pam_setcred(); -#endif /* USE_PAM */ - - /* Fork the child. */ - if ((pid = fork()) == 0) { - /* Child. Reinitialize the log since the pid has changed. */ - log_init(av0, options.log_level, options.log_facility, log_stderr); - - /* - * Create a new session and process group since the 4.4BSD - * setlogin() affects the entire process group. - */ - if (setsid() < 0) - error("setsid failed: %.100s", strerror(errno)); - -#ifdef USE_PIPES - /* - * Redirect stdin. We close the parent side of the socket - * pair, and make the child side the standard input. - */ - close(pin[1]); - if (dup2(pin[0], 0) < 0) - perror("dup2 stdin"); - close(pin[0]); - - /* Redirect stdout. */ - close(pout[0]); - if (dup2(pout[1], 1) < 0) - perror("dup2 stdout"); - close(pout[1]); - - /* Redirect stderr. */ - close(perr[0]); - if (dup2(perr[1], 2) < 0) - perror("dup2 stderr"); - close(perr[1]); -#else /* USE_PIPES */ - /* - * Redirect stdin, stdout, and stderr. Stdin and stdout will - * use the same socket, as some programs (particularly rdist) - * seem to depend on it. - */ - close(inout[1]); - close(err[1]); - if (dup2(inout[0], 0) < 0) /* stdin */ - perror("dup2 stdin"); - if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ - perror("dup2 stdout"); - if (dup2(err[0], 2) < 0) /* stderr */ - perror("dup2 stderr"); -#endif /* USE_PIPES */ - - /* Do processing for the child (exec command etc). */ - do_child(command, pw, NULL, display, auth_proto, auth_data, NULL); - /* NOTREACHED */ - } - if (pid < 0) - packet_disconnect("fork failed: %.100s", strerror(errno)); -#ifdef USE_PIPES - /* We are the parent. Close the child sides of the pipes. */ - close(pin[0]); - close(pout[1]); - close(perr[1]); - - /* Enter the interactive session. */ - server_loop(pid, pin[1], pout[0], perr[0]); - /* server_loop has closed pin[1], pout[1], and perr[1]. */ -#else /* USE_PIPES */ - /* We are the parent. Close the child sides of the socket pairs. */ - close(inout[0]); - close(err[0]); - - /* - * Enter the interactive session. Note: server_loop must be able to - * handle the case that fdin and fdout are the same. - */ - server_loop(pid, inout[1], inout[1], err[1]); - /* server_loop has closed inout[1] and err[1]. */ -#endif /* USE_PIPES */ -} - -/* - * This is called to fork and execute a command when we have a tty. This - * will call do_child from the child, and server_loop from the parent after - * setting up file descriptors, controlling tty, updating wtmp, utmp, - * lastlog, and other such operations. - */ -void -do_exec_pty(const char *command, int ptyfd, int ttyfd, - const char *ttyname, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data) -{ - int pid, fdout; - int ptymaster; - const char *hostname; - time_t last_login_time; - char buf[100], *time_string; - FILE *f; - char line[256]; - struct stat st; - int quiet_login; - struct sockaddr_storage from; - socklen_t fromlen; - struct pty_cleanup_context cleanup_context; - - /* Get remote host name. */ - hostname = get_canonical_hostname(); - - /* - * Get the time when the user last logged in. Buf will be set to - * contain the hostname the last login was from. - */ - if (!options.use_login) { - last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, - buf, sizeof(buf)); - } - setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1); - -#ifdef USE_PAM - do_pam_session(pw->pw_name, ttyname); - do_pam_setcred(); -#endif /* USE_PAM */ - - /* Fork the child. */ - if ((pid = fork()) == 0) { - pid = getpid(); - - /* Child. Reinitialize the log because the pid has - changed. */ - log_init(av0, options.log_level, options.log_facility, log_stderr); +/* diffie-hellman-group-exchange-sha1 */ - /* Close the master side of the pseudo tty. */ - close(ptyfd); - - /* Make the pseudo tty our controlling tty. */ - pty_make_controlling_tty(&ttyfd, ttyname); - - /* Redirect stdin from the pseudo tty. */ - if (dup2(ttyfd, fileno(stdin)) < 0) - error("dup2 stdin failed: %.100s", strerror(errno)); - - /* Redirect stdout to the pseudo tty. */ - if (dup2(ttyfd, fileno(stdout)) < 0) - error("dup2 stdin failed: %.100s", strerror(errno)); - - /* Redirect stderr to the pseudo tty. */ - if (dup2(ttyfd, fileno(stderr)) < 0) - error("dup2 stdin failed: %.100s", strerror(errno)); - - /* Close the extra descriptor for the pseudo tty. */ - close(ttyfd); - - /* - * Get IP address of client. This is needed because we want - * to record where the user logged in from. If the - * connection is not a socket, let the ip address be 0.0.0.0. - */ - memset(&from, 0, sizeof(from)); - if (packet_get_connection_in() == packet_get_connection_out()) { - fromlen = sizeof(from); - if (getpeername(packet_get_connection_in(), - (struct sockaddr *) & from, &fromlen) < 0) { - debug("getpeername: %.100s", strerror(errno)); - fatal_cleanup(); - } - } - /* Record that there was a login on that terminal. */ - record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname, - (struct sockaddr *)&from); - - /* Check if .hushlogin exists. */ - snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); - quiet_login = stat(line, &st) >= 0; - -#ifdef USE_PAM - if (!quiet_login) - print_pam_messages(); -#endif /* USE_PAM */ - - /* - * If the user has logged in before, display the time of last - * login. However, don't display anything extra if a command - * has been specified (so that ssh can be used to execute - * commands on a remote machine without users knowing they - * are going to another machine). Login(1) will do this for - * us as well, so check if login(1) is used - */ - if (command == NULL && last_login_time != 0 && !quiet_login && - !options.use_login) { - /* Convert the date to a string. */ - time_string = ctime(&last_login_time); - /* Remove the trailing newline. */ - if (strchr(time_string, '\n')) - *strchr(time_string, '\n') = 0; - /* Display the last login time. Host if displayed - if known. */ - if (strcmp(buf, "") == 0) - printf("Last login: %s\r\n", time_string); - else - printf("Last login: %s from %s\r\n", time_string, buf); - } - /* - * Print /etc/motd unless a command was specified or printing - * it was disabled in server options or login(1) will be - * used. Note that some machines appear to print it in - * /etc/profile or similar. - */ - if (command == NULL && options.print_motd && !quiet_login && - !options.use_login) { - /* Print /etc/motd if it exists. */ - f = fopen("/etc/motd", "r"); - if (f) { - while (fgets(line, sizeof(line), f)) - fputs(line, stdout); - fclose(f); - } - } - /* Do common processing for the child, such as execing the command. */ - do_child(command, pw, term, display, auth_proto, auth_data, ttyname); - /* NOTREACHED */ - } - if (pid < 0) - packet_disconnect("fork failed: %.100s", strerror(errno)); - /* Parent. Close the slave side of the pseudo tty. */ - close(ttyfd); - - /* - * Add a cleanup function to clear the utmp entry and record logout - * time in case we call fatal() (e.g., the connection gets closed). - */ - cleanup_context.pid = pid; - cleanup_context.ttyname = ttyname; - fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context); - fatal_remove_cleanup(pty_release_proc, (void *) ttyname); - - /* - * Create another descriptor of the pty master side for use as the - * standard input. We could use the original descriptor, but this - * simplifies code in server_loop. The descriptor is bidirectional. - */ - fdout = dup(ptyfd); - if (fdout < 0) - packet_disconnect("dup #1 failed: %.100s", strerror(errno)); - - /* we keep a reference to the pty master */ - ptymaster = dup(ptyfd); - if (ptymaster < 0) - packet_disconnect("dup #2 failed: %.100s", strerror(errno)); - - /* Enter interactive session. */ - server_loop(pid, ptyfd, fdout, -1); - /* server_loop _has_ closed ptyfd and fdout. */ - - /* Cancel the cleanup function. */ - fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context); - - /* Record that the user has logged out. */ - record_logout(pid, ttyname); - - /* Release the pseudo-tty. */ - pty_release(ttyname); - - /* - * Close the server side of the socket pairs. We must do this after - * the pty cleanup, so that another process doesn't get this pty - * while we're still cleaning up. - */ - if (close(ptymaster) < 0) - error("close(ptymaster): %s", strerror(errno)); -} - -/* - * Sets the value of the given variable in the environment. If the variable - * already exists, its value is overriden. - */ -void -child_set_env(char ***envp, unsigned int *envsizep, const char *name, - const char *value) -{ - unsigned int i, namelen; - char **env; - - /* - * Find the slot where the value should be stored. If the variable - * already exists, we reuse the slot; otherwise we append a new slot - * at the end of the array, expanding if necessary. - */ - env = *envp; - namelen = strlen(name); - for (i = 0; env[i]; i++) - if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') - break; - if (env[i]) { - /* Reuse the slot. */ - xfree(env[i]); - } else { - /* New variable. Expand if necessary. */ - if (i >= (*envsizep) - 1) { - (*envsizep) += 50; - env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); - } - /* Need to set the NULL pointer at end of array beyond the new slot. */ - env[i + 1] = NULL; - } - - /* Allocate space and format the variable in the appropriate slot. */ - env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); - snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); -} - -/* - * Reads environment variables from the given file and adds/overrides them - * into the environment. If the file does not exist, this does nothing. - * Otherwise, it must consist of empty lines, comments (line starts with '#') - * and assignments of the form name=value. No other forms are allowed. - */ -void -read_environment_file(char ***env, unsigned int *envsize, - const char *filename) -{ - FILE *f; - char buf[4096]; - char *cp, *value; - - f = fopen(filename, "r"); - if (!f) - return; - - while (fgets(buf, sizeof(buf), f)) { - for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) - ; - if (!*cp || *cp == '#' || *cp == '\n') - continue; - if (strchr(cp, '\n')) - *strchr(cp, '\n') = '\0'; - value = strchr(cp, '='); - if (value == NULL) { - fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); - continue; - } - /* Replace the equals sign by nul, and advance value to the value string. */ - *value = '\0'; - value++; - child_set_env(env, envsize, cp, value); - } - fclose(f); -} - -#ifdef USE_PAM -/* - * Sets any environment variables which have been specified by PAM - */ -void do_pam_environment(char ***env, int *envsize) +void +ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit) { - char *equals, var_name[512], var_val[512]; - char **pam_env; +#ifdef DEBUG_KEXDH int i; - - if ((pam_env = fetch_pam_environment()) == NULL) - return; - - for(i = 0; pam_env[i] != NULL; i++) { - if ((equals = strstr(pam_env[i], "=")) == NULL) - continue; - - if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) - { - memset(var_name, '\0', sizeof(var_name)); - memset(var_val, '\0', sizeof(var_val)); - - strncpy(var_name, pam_env[i], equals - pam_env[i]); - strcpy(var_val, equals + 1); - - debug("PAM environment: %s=%s", var_name, var_val); - - child_set_env(env, envsize, var_name, var_val); - } - } -} -#endif /* USE_PAM */ - -/* - * Performs common processing for the child, such as setting up the - * environment, closing extra file descriptors, setting the user and group - * ids, and executing the command or shell. - */ -void -do_child(const char *command, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data, const char *ttyname) -{ - const char *shell, *cp = NULL; - char buf[256]; - FILE *f; - unsigned int envsize, i; - char **env; - extern char **environ; - struct stat st; - char *argv[10]; - -#ifndef USE_PAM /* pam_nologin handles this */ - /* Check /etc/nologin. */ - f = fopen("/etc/nologin", "r"); - if (f) { - /* /etc/nologin exists. Print its contents and exit. */ - while (fgets(buf, sizeof(buf), f)) - fputs(buf, stderr); - fclose(f); - if (pw->pw_uid != 0) - exit(254); - } -#endif /* USE_PAM */ - - /* Set login name in the kernel. */ - if (setlogin(pw->pw_name) < 0) - error("setlogin failed: %s", strerror(errno)); - - /* Set uid, gid, and groups. */ - /* Login(1) does this as well, and it needs uid 0 for the "-h" - switch, so we let login(1) to this for us. */ - if (!options.use_login) { - if (getuid() == 0 || geteuid() == 0) { - if (setgid(pw->pw_gid) < 0) { - perror("setgid"); - exit(1); - } - /* Initialize the group list. */ - if (initgroups(pw->pw_name, pw->pw_gid) < 0) { - perror("initgroups"); - exit(1); - } - endgrent(); - - /* Permanently switch to the desired uid. */ - permanently_set_uid(pw->pw_uid); - } - if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) - fatal("Failed to set uids to %d.", (int) pw->pw_uid); - } - /* - * Get the shell from the password data. An empty shell field is - * legal, and means /bin/sh. - */ - shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; - -#ifdef AFS - /* Try to get AFS tokens for the local cell. */ - if (k_hasafs()) { - char cell[64]; - - if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) - krb_afslog(cell, 0); - - krb_afslog(0, 0); - } -#endif /* AFS */ - - /* Initialize the environment. */ - envsize = 100; - env = xmalloc(envsize * sizeof(char *)); - env[0] = NULL; - - if (!options.use_login) { - /* Set basic environment. */ - child_set_env(&env, &envsize, "USER", pw->pw_name); - child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); - child_set_env(&env, &envsize, "HOME", pw->pw_dir); - child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); - - snprintf(buf, sizeof buf, "%.200s/%.50s", - _PATH_MAILDIR, pw->pw_name); - child_set_env(&env, &envsize, "MAIL", buf); - - /* Normal systems set SHELL by default. */ - child_set_env(&env, &envsize, "SHELL", shell); - } - if (getenv("TZ")) - child_set_env(&env, &envsize, "TZ", getenv("TZ")); - - /* Set custom environment options from RSA authentication. */ - while (custom_environment) { - struct envstring *ce = custom_environment; - char *s = ce->s; - int i; - for (i = 0; s[i] != '=' && s[i]; i++); - if (s[i] == '=') { - s[i] = 0; - child_set_env(&env, &envsize, s, s + i + 1); - } - custom_environment = ce->next; - xfree(ce->s); - xfree(ce); - } - - snprintf(buf, sizeof buf, "%.50s %d %d", - get_remote_ipaddr(), get_remote_port(), get_local_port()); - child_set_env(&env, &envsize, "SSH_CLIENT", buf); - - if (ttyname) - child_set_env(&env, &envsize, "SSH_TTY", ttyname); - if (term) - child_set_env(&env, &envsize, "TERM", term); - if (display) - child_set_env(&env, &envsize, "DISPLAY", display); - -#ifdef _AIX - { - char *authstate,*krb5cc; - - if ((authstate = getenv("AUTHSTATE")) != NULL) - child_set_env(&env,&envsize,"AUTHSTATE",authstate); - - if ((krb5cc = getenv("KRB5CCNAME")) != NULL) - child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc); - } #endif + int payload_len, dlen; + int slen, nbits; + unsigned char *signature = NULL; + unsigned char *server_host_key_blob = NULL; + unsigned int sbloblen; + unsigned int klen, kout; + unsigned char *kbuf; + unsigned char *hash; + BIGNUM *shared_secret = 0; + DH *dh; + BIGNUM *dh_client_pub = 0; + Key *hostkey; + + hostkey = get_hostkey_by_type(kex->hostkey_type); + if (hostkey == NULL) + fatal("Unsupported hostkey type %d", kex->hostkey_type); + +/* KEXDHGEX */ + debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST."); + packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_REQUEST); + nbits = packet_get_int(); + dh = choose_dh(nbits); + + debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP."); + packet_start(SSH2_MSG_KEX_DH_GEX_GROUP); + packet_put_bignum2(dh->p); + packet_put_bignum2(dh->g); + packet_send(); + packet_write_wait(); -#ifdef KRB4 - { - extern char *ticket; - - if (ticket) - child_set_env(&env, &envsize, "KRBTKFILE", ticket); - } -#endif /* KRB4 */ - -#ifdef USE_PAM - /* Pull in any environment variables that may have been set by PAM. */ - do_pam_environment(&env, &envsize); -#endif /* USE_PAM */ - - if (xauthfile) - child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); - - if (auth_get_socket_name() != NULL) - child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, - auth_get_socket_name()); - - read_environment_file(&env,&envsize,"/etc/environment"); - - /* read $HOME/.ssh/environment. */ - if (!options.use_login) { - snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); - read_environment_file(&env, &envsize, buf); - } - if (debug_flag) { - /* dump the environment */ - fprintf(stderr, "Environment:\n"); - for (i = 0; env[i]; i++) - fprintf(stderr, " %.200s\n", env[i]); - } - /* - * Close the connection descriptors; note that this is the child, and - * the server will still have the socket open, and it is important - * that we do not shutdown it. Note that the descriptors cannot be - * closed before building the environment, as we call - * get_remote_ipaddr there. - */ - if (packet_get_connection_in() == packet_get_connection_out()) - close(packet_get_connection_in()); - else { - close(packet_get_connection_in()); - close(packet_get_connection_out()); - } - /* - * Close all descriptors related to channels. They will still remain - * open in the parent. - */ - /* XXX better use close-on-exec? -markus */ - channel_close_all(); - - /* - * Close any extra file descriptors. Note that there may still be - * descriptors left by system functions. They will be closed later. - */ - endpwent(); - - /* - * Close any extra open file descriptors so that we don\'t have them - * hanging around in clients. Note that we want to do this after - * initgroups, because at least on Solaris 2.3 it leaves file - * descriptors open. - */ - for (i = 3; i < 64; i++) - close(i); - - /* Change current directory to the user\'s home directory. */ - if (chdir(pw->pw_dir) < 0) - fprintf(stderr, "Could not chdir to home directory %s: %s\n", - pw->pw_dir, strerror(errno)); - - /* - * Must take new environment into use so that .ssh/rc, /etc/sshrc and - * xauth are run in the proper environment. - */ - environ = env; - - /* - * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first - * in this order). - */ - if (!options.use_login) { - if (stat(SSH_USER_RC, &st) >= 0) { - if (debug_flag) - fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); - - f = popen("/bin/sh " SSH_USER_RC, "w"); - if (f) { - if (auth_proto != NULL && auth_data != NULL) - fprintf(f, "%s %s\n", auth_proto, auth_data); - pclose(f); - } else - fprintf(stderr, "Could not run %s\n", SSH_USER_RC); - } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { - if (debug_flag) - fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); - - f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); - if (f) { - if (auth_proto != NULL && auth_data != NULL) - fprintf(f, "%s %s\n", auth_proto, auth_data); - pclose(f); - } else - fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); - } -#ifdef XAUTH_PATH - else { - /* Add authority data to .Xauthority if appropriate. */ - if (auth_proto != NULL && auth_data != NULL) { - if (debug_flag) - fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", - XAUTH_PATH, display, auth_proto, auth_data); - - f = popen(XAUTH_PATH " -q -", "w"); - if (f) { - fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); - pclose(f); - } else - fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); - } - } -#endif /* XAUTH_PATH */ - - /* Get the last component of the shell name. */ - cp = strrchr(shell, '/'); - if (cp) - cp++; - else - cp = shell; - } - /* - * If we have no command, execute the shell. In this case, the shell - * name to be passed in argv[0] is preceded by '-' to indicate that - * this is a login shell. - */ - if (!command) { - if (!options.use_login) { - char buf[256]; + debug("Wait SSH2_MSG_KEX_DH_GEX_INIT."); + packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT); - /* - * Check for mail if we have a tty and it was enabled - * in server options. - */ - if (ttyname && options.check_mail) { - char *mailbox; - struct stat mailstat; - mailbox = getenv("MAIL"); - if (mailbox != NULL) { - if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) - printf("No mail.\n"); - else if (mailstat.st_mtime < mailstat.st_atime) - printf("You have mail.\n"); - else - printf("You have new mail.\n"); - } - } - /* Start the shell. Set initial character to '-'. */ - buf[0] = '-'; - strncpy(buf + 1, cp, sizeof(buf) - 1); - buf[sizeof(buf) - 1] = 0; - - /* Execute the shell. */ - argv[0] = buf; - argv[1] = NULL; - execve(shell, argv, env); - - /* Executing the shell failed. */ - perror(shell); - exit(1); + /* key, cert */ + dh_client_pub = BN_new(); + if (dh_client_pub == NULL) + fatal("dh_client_pub == NULL"); + packet_get_bignum2(dh_client_pub, &dlen); - } else { - /* Launch login(1). */ +#ifdef DEBUG_KEXDH + fprintf(stderr, "\ndh_client_pub= "); + BN_print_fp(stderr, dh_client_pub); + fprintf(stderr, "\n"); + debug("bits %d", BN_num_bits(dh_client_pub)); +#endif - execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(), - "-p", "-f", "--", pw->pw_name, NULL); +#ifdef DEBUG_KEXDH + fprintf(stderr, "\np= "); + BN_print_fp(stderr, dh->p); + fprintf(stderr, "\ng= "); + bn_print(dh->g); + fprintf(stderr, "\npub= "); + BN_print_fp(stderr, dh->pub_key); + fprintf(stderr, "\n"); + DHparams_print_fp(stderr, dh); +#endif + if (!dh_pub_is_valid(dh, dh_client_pub)) + packet_disconnect("bad client public DH value"); + + klen = DH_size(dh); + kbuf = xmalloc(klen); + kout = DH_compute_key(kbuf, dh_client_pub, dh); + +#ifdef DEBUG_KEXDH + debug("shared secret: len %d/%d", klen, kout); + fprintf(stderr, "shared secret == "); + for (i = 0; i< kout; i++) + fprintf(stderr, "%02x", (kbuf[i])&0xff); + fprintf(stderr, "\n"); +#endif + shared_secret = BN_new(); + + BN_bin2bn(kbuf, kout, shared_secret); + memset(kbuf, 0, klen); + xfree(kbuf); + + /* XXX precompute? */ + key_to_blob(hostkey, &server_host_key_blob, &sbloblen); + + /* calc H */ /* XXX depends on 'kex' */ + hash = kex_hash_gex( + client_version_string, + server_version_string, + buffer_ptr(client_kexinit), buffer_len(client_kexinit), + buffer_ptr(server_kexinit), buffer_len(server_kexinit), + (char *)server_host_key_blob, sbloblen, + nbits, dh->p, dh->g, + dh_client_pub, + dh->pub_key, + shared_secret + ); + buffer_free(client_kexinit); + buffer_free(server_kexinit); + xfree(client_kexinit); + xfree(server_kexinit); +#ifdef DEBUG_KEXDH + fprintf(stderr, "hash == "); + for (i = 0; i< 20; i++) + fprintf(stderr, "%02x", (hash[i])&0xff); + fprintf(stderr, "\n"); +#endif + /* save session id := H */ + /* XXX hashlen depends on KEX */ + session_id2_len = 20; + session_id2 = xmalloc(session_id2_len); + memcpy(session_id2, hash, session_id2_len); + + /* sign H */ + /* XXX hashlen depends on KEX */ + key_sign(hostkey, &signature, &slen, hash, 20); + + destroy_sensitive_data(); + + /* send server hostkey, DH pubkey 'f' and singed H */ + packet_start(SSH2_MSG_KEX_DH_GEX_REPLY); + packet_put_string((char *)server_host_key_blob, sbloblen); + packet_put_bignum2(dh->pub_key); /* f */ + packet_put_string((char *)signature, slen); + packet_send(); + xfree(signature); + xfree(server_host_key_blob); + packet_write_wait(); - /* Login couldn't be executed, die. */ + kex_derive_keys(kex, hash, shared_secret); + packet_set_kex(kex); - perror("login"); - exit(1); - } - } - /* - * Execute the command using the user's shell. This uses the -c - * option to execute the command. - */ - argv[0] = (char *) cp; - argv[1] = "-c"; - argv[2] = (char *) command; - argv[3] = NULL; - execve(shell, argv, env); - perror(shell); - exit(1); + /* have keys, free DH */ + DH_free(dh); }