diff options
Diffstat (limited to 'crypto/openssh/ssh.c')
| -rw-r--r-- | crypto/openssh/ssh.c | 2062 |
1 files changed, 2062 insertions, 0 deletions
diff --git a/crypto/openssh/ssh.c b/crypto/openssh/ssh.c new file mode 100644 index 0000000..19abc06 --- /dev/null +++ b/crypto/openssh/ssh.c @@ -0,0 +1,2062 @@ +/* $OpenBSD: ssh.c,v 1.418 2015/05/04 06:10:48 djm Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * Ssh client program. This program can be used to log into a remote machine. + * The software supports strong authentication, encryption, and forwarding + * of X11, TCP/IP, and authentication 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". + * + * Copyright (c) 1999 Niels Provos. All rights reserved. + * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. + * + * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> + * in Canada (German citizen). + * + * 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("$FreeBSD$"); + +#include <sys/types.h> +#ifdef HAVE_SYS_STAT_H +# include <sys/stat.h> +#endif +#include <sys/resource.h> +#include <sys/ioctl.h> +#include <sys/socket.h> +#include <sys/wait.h> + +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <netdb.h> +#ifdef HAVE_PATHS_H +#include <paths.h> +#endif +#include <pwd.h> +#include <signal.h> +#include <stdarg.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <limits.h> + +#include <netinet/in.h> +#include <arpa/inet.h> + +#ifdef WITH_OPENSSL +#include <openssl/evp.h> +#include <openssl/err.h> +#endif +#include "openbsd-compat/openssl-compat.h" +#include "openbsd-compat/sys-queue.h" + +#include "xmalloc.h" +#include "ssh.h" +#include "ssh1.h" +#include "ssh2.h" +#include "canohost.h" +#include "compat.h" +#include "cipher.h" +#include "digest.h" +#include "packet.h" +#include "buffer.h" +#include "channels.h" +#include "key.h" +#include "authfd.h" +#include "authfile.h" +#include "pathnames.h" +#include "dispatch.h" +#include "clientloop.h" +#include "log.h" +#include "misc.h" +#include "readconf.h" +#include "sshconnect.h" +#include "kex.h" +#include "mac.h" +#include "sshpty.h" +#include "match.h" +#include "msg.h" +#include "uidswap.h" +#include "roaming.h" +#include "version.h" +#include "ssherr.h" + +#ifdef ENABLE_PKCS11 +#include "ssh-pkcs11.h" +#endif + +extern char *__progname; + +/* Saves a copy of argv for setproctitle emulation */ +#ifndef HAVE_SETPROCTITLE +static char **saved_av; +#endif + +/* Flag indicating whether debug mode is on. May be set on the command line. */ +int debug_flag = 0; + +/* Flag indicating whether a tty should be requested */ +int tty_flag = 0; + +/* don't exec a shell */ +int no_shell_flag = 0; + +/* + * Flag indicating that nothing should be read from stdin. This can be set + * on the command line. + */ +int stdin_null_flag = 0; + +/* + * Flag indicating that the current process should be backgrounded and + * a new slave launched in the foreground for ControlPersist. + */ +int need_controlpersist_detach = 0; + +/* Copies of flags for ControlPersist foreground slave */ +int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty; + +/* + * Flag indicating that ssh should fork after authentication. This is useful + * so that the passphrase can be entered manually, and then ssh goes to the + * background. + */ +int fork_after_authentication_flag = 0; + +/* forward stdio to remote host and port */ +char *stdio_forward_host = NULL; +int stdio_forward_port = 0; + +/* + * General data structure for command line options and options configurable + * in configuration files. See readconf.h. + */ +Options options; + +/* optional user configfile */ +char *config = NULL; + +/* + * Name of the host we are connecting to. This is the name given on the + * command line, or the HostName specified for the user-supplied name in a + * configuration file. + */ +char *host; + +/* socket address the host resolves to */ +struct sockaddr_storage hostaddr; + +/* Private host keys. */ +Sensitive sensitive_data; + +/* Original real UID. */ +uid_t original_real_uid; +uid_t original_effective_uid; + +/* command to be executed */ +Buffer command; + +/* Should we execute a command or invoke a subsystem? */ +int subsystem_flag = 0; + +/* # of replies received for global requests */ +static int remote_forward_confirms_received = 0; + +/* mux.c */ +extern int muxserver_sock; +extern u_int muxclient_command; + +/* Prints a help message to the user. This function never returns. */ + +static void +usage(void) +{ + fprintf(stderr, +"usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" +" [-D [bind_address:]port] [-E log_file] [-e escape_char]\n" +" [-F configfile] [-I pkcs11] [-i identity_file]\n" +" [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n" +" [-O ctl_cmd] [-o option] [-p port]\n" +" [-Q cipher | cipher-auth | mac | kex | key]\n" +" [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n" +" [-w local_tun[:remote_tun]] [user@]hostname [command]\n" + ); + exit(255); +} + +static int ssh_session(void); +static int ssh_session2(void); +static void load_public_identity_files(void); +static void main_sigchld_handler(int); + +/* from muxclient.c */ +void muxclient(const char *); +void muxserver_listen(void); + +/* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */ +static void +tilde_expand_paths(char **paths, u_int num_paths) +{ + u_int i; + char *cp; + + for (i = 0; i < num_paths; i++) { + cp = tilde_expand_filename(paths[i], original_real_uid); + free(paths[i]); + paths[i] = cp; + } +} + +/* + * Attempt to resolve a host name / port to a set of addresses and + * optionally return any CNAMEs encountered along the way. + * Returns NULL on failure. + * NB. this function must operate with a options having undefined members. + */ +static struct addrinfo * +resolve_host(const char *name, int port, int logerr, char *cname, size_t clen) +{ + char strport[NI_MAXSERV]; + struct addrinfo hints, *res; + int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1; + + if (port <= 0) + port = default_ssh_port(); + + snprintf(strport, sizeof strport, "%u", port); + memset(&hints, 0, sizeof(hints)); + hints.ai_family = options.address_family == -1 ? + AF_UNSPEC : options.address_family; + hints.ai_socktype = SOCK_STREAM; + if (cname != NULL) + hints.ai_flags = AI_CANONNAME; + if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) { + if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA)) + loglevel = SYSLOG_LEVEL_ERROR; + do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s", + __progname, name, ssh_gai_strerror(gaierr)); + return NULL; + } + if (cname != NULL && res->ai_canonname != NULL) { + if (strlcpy(cname, res->ai_canonname, clen) >= clen) { + error("%s: host \"%s\" cname \"%s\" too long (max %lu)", + __func__, name, res->ai_canonname, (u_long)clen); + if (clen > 0) + *cname = '\0'; + } + } + return res; +} + +/* + * Attempt to resolve a numeric host address / port to a single address. + * Returns a canonical address string. + * Returns NULL on failure. + * NB. this function must operate with a options having undefined members. + */ +static struct addrinfo * +resolve_addr(const char *name, int port, char *caddr, size_t clen) +{ + char addr[NI_MAXHOST], strport[NI_MAXSERV]; + struct addrinfo hints, *res; + int gaierr; + + if (port <= 0) + port = default_ssh_port(); + snprintf(strport, sizeof strport, "%u", port); + memset(&hints, 0, sizeof(hints)); + hints.ai_family = options.address_family == -1 ? + AF_UNSPEC : options.address_family; + hints.ai_socktype = SOCK_STREAM; + hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV; + if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) { + debug2("%s: could not resolve name %.100s as address: %s", + __func__, name, ssh_gai_strerror(gaierr)); + return NULL; + } + if (res == NULL) { + debug("%s: getaddrinfo %.100s returned no addresses", + __func__, name); + return NULL; + } + if (res->ai_next != NULL) { + debug("%s: getaddrinfo %.100s returned multiple addresses", + __func__, name); + goto fail; + } + if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen, + addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) { + debug("%s: Could not format address for name %.100s: %s", + __func__, name, ssh_gai_strerror(gaierr)); + goto fail; + } + if (strlcpy(caddr, addr, clen) >= clen) { + error("%s: host \"%s\" addr \"%s\" too long (max %lu)", + __func__, name, addr, (u_long)clen); + if (clen > 0) + *caddr = '\0'; + fail: + freeaddrinfo(res); + return NULL; + } + return res; +} + +/* + * Check whether the cname is a permitted replacement for the hostname + * and perform the replacement if it is. + * NB. this function must operate with a options having undefined members. + */ +static int +check_follow_cname(char **namep, const char *cname) +{ + int i; + struct allowed_cname *rule; + + if (*cname == '\0' || options.num_permitted_cnames == 0 || + strcmp(*namep, cname) == 0) + return 0; + if (options.canonicalize_hostname == SSH_CANONICALISE_NO) + return 0; + /* + * Don't attempt to canonicalize names that will be interpreted by + * a proxy unless the user specifically requests so. + */ + if (!option_clear_or_none(options.proxy_command) && + options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) + return 0; + debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname); + for (i = 0; i < options.num_permitted_cnames; i++) { + rule = options.permitted_cnames + i; + if (match_pattern_list(*namep, rule->source_list, 1) != 1 || + match_pattern_list(cname, rule->target_list, 1) != 1) + continue; + verbose("Canonicalized DNS aliased hostname " + "\"%s\" => \"%s\"", *namep, cname); + free(*namep); + *namep = xstrdup(cname); + return 1; + } + return 0; +} + +/* + * Attempt to resolve the supplied hostname after applying the user's + * canonicalization rules. Returns the address list for the host or NULL + * if no name was found after canonicalization. + * NB. this function must operate with a options having undefined members. + */ +static struct addrinfo * +resolve_canonicalize(char **hostp, int port) +{ + int i, ndots; + char *cp, *fullhost, newname[NI_MAXHOST]; + struct addrinfo *addrs; + + if (options.canonicalize_hostname == SSH_CANONICALISE_NO) + return NULL; + + /* + * Don't attempt to canonicalize names that will be interpreted by + * a proxy unless the user specifically requests so. + */ + if (!option_clear_or_none(options.proxy_command) && + options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) + return NULL; + + /* Try numeric hostnames first */ + if ((addrs = resolve_addr(*hostp, port, + newname, sizeof(newname))) != NULL) { + debug2("%s: hostname %.100s is address", __func__, *hostp); + if (strcasecmp(*hostp, newname) != 0) { + debug2("%s: canonicalised address \"%s\" => \"%s\"", + __func__, *hostp, newname); + free(*hostp); + *hostp = xstrdup(newname); + } + return addrs; + } + + /* Don't apply canonicalization to sufficiently-qualified hostnames */ + ndots = 0; + for (cp = *hostp; *cp != '\0'; cp++) { + if (*cp == '.') + ndots++; + } + if (ndots > options.canonicalize_max_dots) { + debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)", + __func__, *hostp, options.canonicalize_max_dots); + return NULL; + } + /* Attempt each supplied suffix */ + for (i = 0; i < options.num_canonical_domains; i++) { + *newname = '\0'; + xasprintf(&fullhost, "%s.%s.", *hostp, + options.canonical_domains[i]); + debug3("%s: attempting \"%s\" => \"%s\"", __func__, + *hostp, fullhost); + if ((addrs = resolve_host(fullhost, port, 0, + newname, sizeof(newname))) == NULL) { + free(fullhost); + continue; + } + /* Remove trailing '.' */ + fullhost[strlen(fullhost) - 1] = '\0'; + /* Follow CNAME if requested */ + if (!check_follow_cname(&fullhost, newname)) { + debug("Canonicalized hostname \"%s\" => \"%s\"", + *hostp, fullhost); + } + free(*hostp); + *hostp = fullhost; + return addrs; + } + if (!options.canonicalize_fallback_local) + fatal("%s: Could not resolve host \"%s\"", __progname, *hostp); + debug2("%s: host %s not found in any suffix", __func__, *hostp); + return NULL; +} + +/* + * Read per-user configuration file. Ignore the system wide config + * file if the user specifies a config file on the command line. + */ +static void +process_config_files(const char *host_arg, struct passwd *pw, int post_canon) +{ + char buf[PATH_MAX]; + int r; + + if (config != NULL) { + if (strcasecmp(config, "none") != 0 && + !read_config_file(config, pw, host, host_arg, &options, + SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0))) + fatal("Can't open user config file %.100s: " + "%.100s", config, strerror(errno)); + } else { + r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, + _PATH_SSH_USER_CONFFILE); + if (r > 0 && (size_t)r < sizeof(buf)) + (void)read_config_file(buf, pw, host, host_arg, + &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF | + (post_canon ? SSHCONF_POSTCANON : 0)); + + /* Read systemwide configuration file after user config. */ + (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, + host, host_arg, &options, + post_canon ? SSHCONF_POSTCANON : 0); + } +} + +/* Rewrite the port number in an addrinfo list of addresses */ +static void +set_addrinfo_port(struct addrinfo *addrs, int port) +{ + struct addrinfo *addr; + + for (addr = addrs; addr != NULL; addr = addr->ai_next) { + switch (addr->ai_family) { + case AF_INET: + ((struct sockaddr_in *)addr->ai_addr)-> + sin_port = htons(port); + break; + case AF_INET6: + ((struct sockaddr_in6 *)addr->ai_addr)-> + sin6_port = htons(port); + break; + } + } +} + +/* + * Main program for the ssh client. + */ +int +main(int ac, char **av) +{ + int i, r, opt, exit_status, use_syslog, config_test = 0; + char *p, *cp, *line, *argv0, buf[PATH_MAX], *host_arg, *logfile; + char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; + char cname[NI_MAXHOST]; + struct stat st; + struct passwd *pw; + int timeout_ms; + extern int optind, optreset; + extern char *optarg; + struct Forward fwd; + struct addrinfo *addrs = NULL; + struct ssh_digest_ctx *md; + u_char conn_hash[SSH_DIGEST_MAX_LENGTH]; + char *conn_hash_hex; + + /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ + sanitise_stdfd(); + + __progname = ssh_get_progname(av[0]); + +#ifndef HAVE_SETPROCTITLE + /* Prepare for later setproctitle emulation */ + /* Save argv so it isn't clobbered by setproctitle() emulation */ + saved_av = xcalloc(ac + 1, sizeof(*saved_av)); + for (i = 0; i < ac; i++) + saved_av[i] = xstrdup(av[i]); + saved_av[i] = NULL; + compat_init_setproctitle(ac, av); + av = saved_av; +#endif + + /* + * Discard other fds that are hanging around. These can cause problem + * with backgrounded ssh processes started by ControlPersist. + */ + closefrom(STDERR_FILENO + 1); + + /* + * Save the original real uid. It will be needed later (uid-swapping + * may clobber the real uid). + */ + original_real_uid = getuid(); + original_effective_uid = geteuid(); + + /* + * Use uid-swapping to give up root privileges for the duration of + * option processing. We will re-instantiate the rights when we are + * ready to create the privileged port, and will permanently drop + * them when the port has been created (actually, when the connection + * has been made, as we may need to create the port several times). + */ + PRIV_END; + +#ifdef HAVE_SETRLIMIT + /* If we are installed setuid root be careful to not drop core. */ + if (original_real_uid != original_effective_uid) { + struct rlimit rlim; + rlim.rlim_cur = rlim.rlim_max = 0; + if (setrlimit(RLIMIT_CORE, &rlim) < 0) + fatal("setrlimit failed: %.100s", strerror(errno)); + } +#endif + /* Get user data. */ + pw = getpwuid(original_real_uid); + if (!pw) { + logit("No user exists for uid %lu", (u_long)original_real_uid); + exit(255); + } + /* Take a copy of the returned structure. */ + pw = pwcopy(pw); + + /* + * Set our umask to something reasonable, as some files are created + * with the default umask. This will make them world-readable but + * writable only by the owner, which is ok for all files for which we + * don't set the modes explicitly. + */ + umask(022); + + /* + * Initialize option structure to indicate that no values have been + * set. + */ + initialize_options(&options); + + /* Parse command-line arguments. */ + host = NULL; + use_syslog = 0; + logfile = NULL; + argv0 = av[0]; + + again: + while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" + "ACD:E:F:GI:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { + switch (opt) { + case '1': + options.protocol = SSH_PROTO_1; + break; + case '2': + options.protocol = SSH_PROTO_2; + break; + case '4': + options.address_family = AF_INET; + break; + case '6': + options.address_family = AF_INET6; + break; + case 'n': + stdin_null_flag = 1; + break; + case 'f': + fork_after_authentication_flag = 1; + stdin_null_flag = 1; + break; + case 'x': + options.forward_x11 = 0; + break; + case 'X': + options.forward_x11 = 1; + break; + case 'y': + use_syslog = 1; + break; + case 'E': + logfile = xstrdup(optarg); + break; + case 'G': + config_test = 1; + break; + case 'Y': + options.forward_x11 = 1; + options.forward_x11_trusted = 1; + break; + case 'g': + options.fwd_opts.gateway_ports = 1; + break; + case 'O': + if (stdio_forward_host != NULL) + fatal("Cannot specify multiplexing " + "command with -W"); + else if (muxclient_command != 0) + fatal("Multiplexing command already specified"); + if (strcmp(optarg, "check") == 0) + muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; + else if (strcmp(optarg, "forward") == 0) + muxclient_command = SSHMUX_COMMAND_FORWARD; + else if (strcmp(optarg, "exit") == 0) + muxclient_command = SSHMUX_COMMAND_TERMINATE; + else if (strcmp(optarg, "stop") == 0) + muxclient_command = SSHMUX_COMMAND_STOP; + else if (strcmp(optarg, "cancel") == 0) + muxclient_command = SSHMUX_COMMAND_CANCEL_FWD; + else + fatal("Invalid multiplex command."); + break; + case 'P': /* deprecated */ + options.use_privileged_port = 0; + break; + case 'Q': + cp = NULL; + if (strcmp(optarg, "cipher") == 0) + cp = cipher_alg_list('\n', 0); + else if (strcmp(optarg, "cipher-auth") == 0) + cp = cipher_alg_list('\n', 1); + else if (strcmp(optarg, "mac") == 0) + cp = mac_alg_list('\n'); + else if (strcmp(optarg, "kex") == 0) + cp = kex_alg_list('\n'); + else if (strcmp(optarg, "key") == 0) + cp = key_alg_list(0, 0); + else if (strcmp(optarg, "key-cert") == 0) + cp = key_alg_list(1, 0); + else if (strcmp(optarg, "key-plain") == 0) + cp = key_alg_list(0, 1); + else if (strcmp(optarg, "protocol-version") == 0) { +#ifdef WITH_SSH1 + cp = xstrdup("1\n2"); +#else + cp = xstrdup("2"); +#endif + } + if (cp == NULL) + fatal("Unsupported query \"%s\"", optarg); + printf("%s\n", cp); + free(cp); + exit(0); + break; + case 'a': + options.forward_agent = 0; + break; + case 'A': + options.forward_agent = 1; + break; + case 'k': + options.gss_deleg_creds = 0; + break; + case 'K': + options.gss_authentication = 1; + options.gss_deleg_creds = 1; + break; + case 'i': + if (stat(optarg, &st) < 0) { + fprintf(stderr, "Warning: Identity file %s " + "not accessible: %s.\n", optarg, + strerror(errno)); + break; + } + add_identity_file(&options, NULL, optarg, 1); + break; + case 'I': +#ifdef ENABLE_PKCS11 + options.pkcs11_provider = xstrdup(optarg); +#else + fprintf(stderr, "no support for PKCS#11.\n"); +#endif + break; + case 't': + if (options.request_tty == REQUEST_TTY_YES) + options.request_tty = REQUEST_TTY_FORCE; + else + options.request_tty = REQUEST_TTY_YES; + break; + case 'v': + if (debug_flag == 0) { + debug_flag = 1; + options.log_level = SYSLOG_LEVEL_DEBUG1; + } else { + if (options.log_level < SYSLOG_LEVEL_DEBUG3) + options.log_level++; + } + break; + case 'V': + if (options.version_addendum && + *options.version_addendum != '\0') + fprintf(stderr, "%s %s, %s\n", SSH_RELEASE, + options.version_addendum, + OPENSSL_VERSION); + else + fprintf(stderr, "%s, %s\n", SSH_RELEASE, + OPENSSL_VERSION); + if (opt == 'V') + exit(0); + break; + case 'w': + if (options.tun_open == -1) + options.tun_open = SSH_TUNMODE_DEFAULT; + options.tun_local = a2tun(optarg, &options.tun_remote); + if (options.tun_local == SSH_TUNID_ERR) { + fprintf(stderr, + "Bad tun device '%s'\n", optarg); + exit(255); + } + break; + case 'W': + if (stdio_forward_host != NULL) + fatal("stdio forward already specified"); + if (muxclient_command != 0) + fatal("Cannot specify stdio forward with -O"); + if (parse_forward(&fwd, optarg, 1, 0)) { + stdio_forward_host = fwd.listen_host; + stdio_forward_port = fwd.listen_port; + free(fwd.connect_host); + } else { + fprintf(stderr, + "Bad stdio forwarding specification '%s'\n", + optarg); + exit(255); + } + options.request_tty = REQUEST_TTY_NO; + no_shell_flag = 1; + options.clear_forwardings = 1; + options.exit_on_forward_failure = 1; + break; + case 'q': + options.log_level = SYSLOG_LEVEL_QUIET; + break; + case 'e': + if (optarg[0] == '^' && optarg[2] == 0 && + (u_char) optarg[1] >= 64 && + (u_char) optarg[1] < 128) + options.escape_char = (u_char) optarg[1] & 31; + else if (strlen(optarg) == 1) + options.escape_char = (u_char) optarg[0]; + else if (strcmp(optarg, "none") == 0) + options.escape_char = SSH_ESCAPECHAR_NONE; + else { + fprintf(stderr, "Bad escape character '%s'.\n", + optarg); + exit(255); + } + break; + case 'c': + if (ciphers_valid(optarg)) { + /* SSH2 only */ + options.ciphers = xstrdup(optarg); + options.cipher = SSH_CIPHER_INVALID; + } else { + /* SSH1 only */ + options.cipher = cipher_number(optarg); + if (options.cipher == -1) { + fprintf(stderr, + "Unknown cipher type '%s'\n", + optarg); + exit(255); + } + if (options.cipher == SSH_CIPHER_3DES) + options.ciphers = "3des-cbc"; + else if (options.cipher == SSH_CIPHER_BLOWFISH) + options.ciphers = "blowfish-cbc"; + else + options.ciphers = (char *)-1; + } + break; + case 'm': + if (mac_valid(optarg)) + options.macs = xstrdup(optarg); + else { + fprintf(stderr, "Unknown mac type '%s'\n", + optarg); + exit(255); + } + break; + case 'M': + if (options.control_master == SSHCTL_MASTER_YES) + options.control_master = SSHCTL_MASTER_ASK; + else + options.control_master = SSHCTL_MASTER_YES; + break; + case 'p': + options.port = a2port(optarg); + if (options.port <= 0) { + fprintf(stderr, "Bad port '%s'\n", optarg); + exit(255); + } + break; + case 'l': + options.user = optarg; + break; + + case 'L': + if (parse_forward(&fwd, optarg, 0, 0)) + add_local_forward(&options, &fwd); + else { + fprintf(stderr, + "Bad local forwarding specification '%s'\n", + optarg); + exit(255); + } + break; + + case 'R': + if (parse_forward(&fwd, optarg, 0, 1)) { + add_remote_forward(&options, &fwd); + } else { + fprintf(stderr, + "Bad remote forwarding specification " + "'%s'\n", optarg); + exit(255); + } + break; + + case 'D': + if (parse_forward(&fwd, optarg, 1, 0)) { + add_local_forward(&options, &fwd); + } else { + fprintf(stderr, + "Bad dynamic forwarding specification " + "'%s'\n", optarg); + exit(255); + } + break; + + case 'C': + options.compression = 1; + break; + case 'N': + no_shell_flag = 1; + options.request_tty = REQUEST_TTY_NO; + break; + case 'T': + options.request_tty = REQUEST_TTY_NO; + break; + case 'o': + line = xstrdup(optarg); + if (process_config_line(&options, pw, + host ? host : "", host ? host : "", line, + "command-line", 0, NULL, SSHCONF_USERCONF) != 0) + exit(255); + free(line); + break; + case 's': + subsystem_flag = 1; + break; + case 'S': + if (options.control_path != NULL) + free(options.control_path); + options.control_path = xstrdup(optarg); + break; + case 'b': + options.bind_address = optarg; + break; + case 'F': + config = optarg; + break; + default: + usage(); + } + } + + ac -= optind; + av += optind; + + if (ac > 0 && !host) { + if (strrchr(*av, '@')) { + p = xstrdup(*av); + cp = strrchr(p, '@'); + if (cp == NULL || cp == p) + usage(); + options.user = p; + *cp = '\0'; + host = xstrdup(++cp); + } else + host = xstrdup(*av); + if (ac > 1) { + optind = optreset = 1; + goto again; + } + ac--, av++; + } + + /* Check that we got a host name. */ + if (!host) + usage(); + + host_arg = xstrdup(host); + +#ifdef WITH_OPENSSL + OpenSSL_add_all_algorithms(); + ERR_load_crypto_strings(); +#endif + + /* Initialize the command to execute on remote host. */ + buffer_init(&command); + + /* + * Save the command to execute on the remote host in a buffer. There + * is no limit on the length of the command, except by the maximum + * packet size. Also sets the tty flag if there is no command. + */ + if (!ac) { + /* No command specified - execute shell on a tty. */ + if (subsystem_flag) { + fprintf(stderr, + "You must specify a subsystem to invoke.\n"); + usage(); + } + } else { + /* A command has been specified. Store it into the buffer. */ + for (i = 0; i < ac; i++) { + if (i) + buffer_append(&command, " ", 1); + buffer_append(&command, av[i], strlen(av[i])); + } + } + + /* Cannot fork to background if no command. */ + if (fork_after_authentication_flag && buffer_len(&command) == 0 && + !no_shell_flag) + fatal("Cannot fork into background without a command " + "to execute."); + + /* + * Initialize "log" output. Since we are the client all output + * goes to stderr unless otherwise specified by -y or -E. + */ + if (use_syslog && logfile != NULL) + fatal("Can't specify both -y and -E"); + if (logfile != NULL) { + log_redirect_stderr_to(logfile); + free(logfile); + } + log_init(argv0, + options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, + SYSLOG_FACILITY_USER, !use_syslog); + + if (debug_flag) + logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION); + + /* Parse the configuration files */ + process_config_files(host_arg, pw, 0); + + /* Hostname canonicalisation needs a few options filled. */ + fill_default_options_for_canonicalization(&options); + + /* If the user has replaced the hostname then take it into use now */ + if (options.hostname != NULL) { + /* NB. Please keep in sync with readconf.c:match_cfg_line() */ + cp = percent_expand(options.hostname, + "h", host, (char *)NULL); + free(host); + host = cp; + free(options.hostname); + options.hostname = xstrdup(host); + } + + /* If canonicalization requested then try to apply it */ + lowercase(host); + if (options.canonicalize_hostname != SSH_CANONICALISE_NO) + addrs = resolve_canonicalize(&host, options.port); + + /* + * If CanonicalizePermittedCNAMEs have been specified but + * other canonicalization did not happen (by not being requested + * or by failing with fallback) then the hostname may still be changed + * as a result of CNAME following. + * + * Try to resolve the bare hostname name using the system resolver's + * usual search rules and then apply the CNAME follow rules. + * + * Skip the lookup if a ProxyCommand is being used unless the user + * has specifically requested canonicalisation for this case via + * CanonicalizeHostname=always + */ + if (addrs == NULL && options.num_permitted_cnames != 0 && + (option_clear_or_none(options.proxy_command) || + options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) { + if ((addrs = resolve_host(host, options.port, + option_clear_or_none(options.proxy_command), + cname, sizeof(cname))) == NULL) { + /* Don't fatal proxied host names not in the DNS */ + if (option_clear_or_none(options.proxy_command)) + cleanup_exit(255); /* logged in resolve_host */ + } else + check_follow_cname(&host, cname); + } + + /* + * If canonicalisation is enabled then re-parse the configuration + * files as new stanzas may match. + */ + if (options.canonicalize_hostname != 0) { + debug("Re-reading configuration after hostname " + "canonicalisation"); + free(options.hostname); + options.hostname = xstrdup(host); + process_config_files(host_arg, pw, 1); + /* + * Address resolution happens early with canonicalisation + * enabled and the port number may have changed since, so + * reset it in address list + */ + if (addrs != NULL && options.port > 0) + set_addrinfo_port(addrs, options.port); + } + + /* Fill configuration defaults. */ + fill_default_options(&options); + + if (options.port == 0) + options.port = default_ssh_port(); + channel_set_af(options.address_family); + + /* Tidy and check options */ + if (options.host_key_alias != NULL) + lowercase(options.host_key_alias); + if (options.proxy_command != NULL && + strcmp(options.proxy_command, "-") == 0 && + options.proxy_use_fdpass) + fatal("ProxyCommand=- and ProxyUseFDPass are incompatible"); + if (options.control_persist && + options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { + debug("UpdateHostKeys=ask is incompatible with ControlPersist; " + "disabling"); + options.update_hostkeys = 0; + } +#ifndef HAVE_CYGWIN + if (original_effective_uid != 0) + options.use_privileged_port = 0; +#endif + + /* reinit */ + log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); + + if (options.request_tty == REQUEST_TTY_YES || + options.request_tty == REQUEST_TTY_FORCE) + tty_flag = 1; + + /* Allocate a tty by default if no command specified. */ + if (buffer_len(&command) == 0) + tty_flag = options.request_tty != REQUEST_TTY_NO; + + /* Force no tty */ + if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) + tty_flag = 0; + /* Do not allocate a tty if stdin is not a tty. */ + if ((!isatty(fileno(stdin)) || stdin_null_flag) && + options.request_tty != REQUEST_TTY_FORCE) { + if (tty_flag) + logit("Pseudo-terminal will not be allocated because " + "stdin is not a terminal."); + tty_flag = 0; + } + + seed_rng(); + + if (options.user == NULL) + options.user = xstrdup(pw->pw_name); + + if (gethostname(thishost, sizeof(thishost)) == -1) + fatal("gethostname: %s", strerror(errno)); + strlcpy(shorthost, thishost, sizeof(shorthost)); + shorthost[strcspn(thishost, ".")] = '\0'; + snprintf(portstr, sizeof(portstr), "%d", options.port); + + /* Find canonic host name. */ + if (strchr(host, '.') == 0) { + struct addrinfo hints; + struct addrinfo *ai = NULL; + int errgai; + memset(&hints, 0, sizeof(hints)); + hints.ai_family = options.address_family; + hints.ai_flags = AI_CANONNAME; + hints.ai_socktype = SOCK_STREAM; + errgai = getaddrinfo(host, NULL, &hints, &ai); + if (errgai == 0) { + if (ai->ai_canonname != NULL) + host = xstrdup(ai->ai_canonname); + freeaddrinfo(ai); + } + } + + if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL || + ssh_digest_update(md, thishost, strlen(thishost)) < 0 || + ssh_digest_update(md, host, strlen(host)) < 0 || + ssh_digest_update(md, portstr, strlen(portstr)) < 0 || + ssh_digest_update(md, options.user, strlen(options.user)) < 0 || + ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0) + fatal("%s: mux digest failed", __func__); + ssh_digest_free(md); + conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1)); + + if (options.local_command != NULL) { + debug3("expanding LocalCommand: %s", options.local_command); + cp = options.local_command; + options.local_command = percent_expand(cp, + "C", conn_hash_hex, + "L", shorthost, + "d", pw->pw_dir, + "h", host, + "l", thishost, + "n", host_arg, + "p", portstr, + "r", options.user, + "u", pw->pw_name, + (char *)NULL); + debug3("expanded LocalCommand: %s", options.local_command); + free(cp); + } + + if (options.control_path != NULL) { + cp = tilde_expand_filename(options.control_path, + original_real_uid); + free(options.control_path); + options.control_path = percent_expand(cp, + "C", conn_hash_hex, + "L", shorthost, + "h", host, + "l", thishost, + "n", host_arg, + "p", portstr, + "r", options.user, + "u", pw->pw_name, + (char *)NULL); + free(cp); + } + free(conn_hash_hex); + + if (config_test) { + dump_client_config(&options, host); + exit(0); + } + + if (muxclient_command != 0 && options.control_path == NULL) + fatal("No ControlPath specified for \"-O\" command"); + if (options.control_path != NULL) + muxclient(options.control_path); + + /* + * If hostname canonicalisation was not enabled, then we may not + * have yet resolved the hostname. Do so now. + */ + if (addrs == NULL && options.proxy_command == NULL) { + if ((addrs = resolve_host(host, options.port, 1, + cname, sizeof(cname))) == NULL) + cleanup_exit(255); /* resolve_host logs the error */ + } + + timeout_ms = options.connection_timeout * 1000; + + /* Open a connection to the remote host. */ + if (ssh_connect(host, addrs, &hostaddr, options.port, + options.address_family, options.connection_attempts, + &timeout_ms, options.tcp_keep_alive, + options.use_privileged_port) != 0) + exit(255); + + if (addrs != NULL) + freeaddrinfo(addrs); + + packet_set_timeout(options.server_alive_interval, + options.server_alive_count_max); + + if (timeout_ms > 0) + debug3("timeout: %d ms remain after connect", timeout_ms); + + /* + * If we successfully made the connection, load the host private key + * in case we will need it later for combined rsa-rhosts + * authentication. This must be done before releasing extra + * privileges, because the file is only readable by root. + * If we cannot access the private keys, load the public keys + * instead and try to execute the ssh-keysign helper instead. + */ + sensitive_data.nkeys = 0; + sensitive_data.keys = NULL; + sensitive_data.external_keysign = 0; + if (options.rhosts_rsa_authentication || + options.hostbased_authentication) { + sensitive_data.nkeys = 9; + sensitive_data.keys = xcalloc(sensitive_data.nkeys, + sizeof(Key)); + for (i = 0; i < sensitive_data.nkeys; i++) + sensitive_data.keys[i] = NULL; + + PRIV_START; + sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, + _PATH_HOST_KEY_FILE, "", NULL, NULL); +#ifdef OPENSSL_HAS_ECC + sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA, + _PATH_HOST_ECDSA_KEY_FILE, "", NULL); +#endif + sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519, + _PATH_HOST_ED25519_KEY_FILE, "", NULL); + sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, + _PATH_HOST_RSA_KEY_FILE, "", NULL); + sensitive_data.keys[4] = key_load_private_cert(KEY_DSA, + _PATH_HOST_DSA_KEY_FILE, "", NULL); +#ifdef OPENSSL_HAS_ECC + sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA, + _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); +#endif + sensitive_data.keys[6] = key_load_private_type(KEY_ED25519, + _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL); + sensitive_data.keys[7] = key_load_private_type(KEY_RSA, + _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); + sensitive_data.keys[8] = key_load_private_type(KEY_DSA, + _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); + PRIV_END; + + if (options.hostbased_authentication == 1 && + sensitive_data.keys[0] == NULL && + sensitive_data.keys[5] == NULL && + sensitive_data.keys[6] == NULL && + sensitive_data.keys[7] == NULL && + sensitive_data.keys[8] == NULL) { +#ifdef OPENSSL_HAS_ECC + sensitive_data.keys[1] = key_load_cert( + _PATH_HOST_ECDSA_KEY_FILE); +#endif + sensitive_data.keys[2] = key_load_cert( + _PATH_HOST_ED25519_KEY_FILE); + sensitive_data.keys[3] = key_load_cert( + _PATH_HOST_RSA_KEY_FILE); + sensitive_data.keys[4] = key_load_cert( + _PATH_HOST_DSA_KEY_FILE); +#ifdef OPENSSL_HAS_ECC + sensitive_data.keys[5] = key_load_public( + _PATH_HOST_ECDSA_KEY_FILE, NULL); +#endif + sensitive_data.keys[6] = key_load_public( + _PATH_HOST_ED25519_KEY_FILE, NULL); + sensitive_data.keys[7] = key_load_public( + _PATH_HOST_RSA_KEY_FILE, NULL); + sensitive_data.keys[8] = key_load_public( + _PATH_HOST_DSA_KEY_FILE, NULL); + sensitive_data.external_keysign = 1; + } + } + /* + * Get rid of any extra privileges that we may have. We will no + * longer need them. Also, extra privileges could make it very hard + * to read identity files and other non-world-readable files from the + * user's home directory if it happens to be on a NFS volume where + * root is mapped to nobody. + */ + if (original_effective_uid == 0) { + PRIV_START; + permanently_set_uid(pw); + } + + /* + * Now that we are back to our own permissions, create ~/.ssh + * directory if it doesn't already exist. + */ + if (config == NULL) { + r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, + strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); + if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) { +#ifdef WITH_SELINUX + ssh_selinux_setfscreatecon(buf); +#endif + if (mkdir(buf, 0700) < 0) + error("Could not create directory '%.200s'.", + buf); +#ifdef WITH_SELINUX + ssh_selinux_setfscreatecon(NULL); +#endif + } + } + /* load options.identity_files */ + load_public_identity_files(); + + /* Expand ~ in known host file names. */ + tilde_expand_paths(options.system_hostfiles, + options.num_system_hostfiles); + tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); + + signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ + signal(SIGCHLD, main_sigchld_handler); + + /* Log into the remote system. Never returns if the login fails. */ + ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, + options.port, pw, timeout_ms); + + if (packet_connection_is_on_socket()) { + verbose("Authenticated to %s ([%s]:%d).", host, + get_remote_ipaddr(), get_remote_port()); + } else { + verbose("Authenticated to %s (via proxy).", host); + } + + /* We no longer need the private host keys. Clear them now. */ + if (sensitive_data.nkeys != 0) { + for (i = 0; i < sensitive_data.nkeys; i++) { + if (sensitive_data.keys[i] != NULL) { + /* Destroys contents safely */ + debug3("clear hostkey %d", i); + key_free(sensitive_data.keys[i]); + sensitive_data.keys[i] = NULL; + } + } + free(sensitive_data.keys); + } + for (i = 0; i < options.num_identity_files; i++) { + free(options.identity_files[i]); + options.identity_files[i] = NULL; + if (options.identity_keys[i]) { + key_free(options.identity_keys[i]); + options.identity_keys[i] = NULL; + } + } + + exit_status = compat20 ? ssh_session2() : ssh_session(); + packet_close(); + + if (options.control_path != NULL && muxserver_sock != -1) + unlink(options.control_path); + + /* Kill ProxyCommand if it is running. */ + ssh_kill_proxy_command(); + + return exit_status; +} + +static void +control_persist_detach(void) +{ + pid_t pid; + int devnull; + + debug("%s: backgrounding master process", __func__); + + /* + * master (current process) into the background, and make the + * foreground process a client of the backgrounded master. + */ + switch ((pid = fork())) { + case -1: + fatal("%s: fork: %s", __func__, strerror(errno)); + case 0: + /* Child: master process continues mainloop */ + break; + default: + /* Parent: set up mux slave to connect to backgrounded master */ + debug2("%s: background process is %ld", __func__, (long)pid); + stdin_null_flag = ostdin_null_flag; + options.request_tty = orequest_tty; + tty_flag = otty_flag; + close(muxserver_sock); + muxserver_sock = -1; + options.control_master = SSHCTL_MASTER_NO; + muxclient(options.control_path); + /* muxclient() doesn't return on success. */ + fatal("Failed to connect to new control master"); + } + if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { + error("%s: open(\"/dev/null\"): %s", __func__, + strerror(errno)); + } else { + if (dup2(devnull, STDIN_FILENO) == -1 || + dup2(devnull, STDOUT_FILENO) == -1) + error("%s: dup2: %s", __func__, strerror(errno)); + if (devnull > STDERR_FILENO) + close(devnull); + } + daemon(1, 1); + setproctitle("%s [mux]", options.control_path); +} + +/* Do fork() after authentication. Used by "ssh -f" */ +static void +fork_postauth(void) +{ + if (need_controlpersist_detach) + control_persist_detach(); + debug("forking to background"); + fork_after_authentication_flag = 0; + if (daemon(1, 1) < 0) + fatal("daemon() failed: %.200s", strerror(errno)); +} + +/* Callback for remote forward global requests */ +static void +ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) +{ + struct Forward *rfwd = (struct Forward *)ctxt; + + /* XXX verbose() on failure? */ + debug("remote forward %s for: listen %s%s%d, connect %s:%d", + type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", + rfwd->listen_path ? rfwd->listen_path : + rfwd->listen_host ? rfwd->listen_host : "", + (rfwd->listen_path || rfwd->listen_host) ? ":" : "", + rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path : + rfwd->connect_host, rfwd->connect_port); + if (rfwd->listen_path == NULL && rfwd->listen_port == 0) { + if (type == SSH2_MSG_REQUEST_SUCCESS) { + rfwd->allocated_port = packet_get_int(); + logit("Allocated port %u for remote forward to %s:%d", + rfwd->allocated_port, + rfwd->connect_host, rfwd->connect_port); + channel_update_permitted_opens(rfwd->handle, + rfwd->allocated_port); + } else { + channel_update_permitted_opens(rfwd->handle, -1); + } + } + + if (type == SSH2_MSG_REQUEST_FAILURE) { + if (options.exit_on_forward_failure) { + if (rfwd->listen_path != NULL) + fatal("Error: remote port forwarding failed " + "for listen path %s", rfwd->listen_path); + else + fatal("Error: remote port forwarding failed " + "for listen port %d", rfwd->listen_port); + } else { + if (rfwd->listen_path != NULL) + logit("Warning: remote port forwarding failed " + "for listen path %s", rfwd->listen_path); + else + logit("Warning: remote port forwarding failed " + "for listen port %d", rfwd->listen_port); + } + } + if (++remote_forward_confirms_received == options.num_remote_forwards) { + debug("All remote forwarding requests processed"); + if (fork_after_authentication_flag) + fork_postauth(); + } +} + +static void +client_cleanup_stdio_fwd(int id, void *arg) +{ + debug("stdio forwarding: done"); + cleanup_exit(0); +} + +static void +ssh_stdio_confirm(int id, int success, void *arg) +{ + if (!success) + fatal("stdio forwarding failed"); +} + +static void +ssh_init_stdio_forwarding(void) +{ + Channel *c; + int in, out; + + if (stdio_forward_host == NULL) + return; + if (!compat20) + fatal("stdio forwarding require Protocol 2"); + + debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); + + if ((in = dup(STDIN_FILENO)) < 0 || + (out = dup(STDOUT_FILENO)) < 0) + fatal("channel_connect_stdio_fwd: dup() in/out failed"); + if ((c = channel_connect_stdio_fwd(stdio_forward_host, + stdio_forward_port, in, out)) == NULL) + fatal("%s: channel_connect_stdio_fwd failed", __func__); + channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); + channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL); +} + +static void +ssh_init_forwarding(void) +{ + int success = 0; + int i; + + /* Initiate local TCP/IP port forwardings. */ + for (i = 0; i < options.num_local_forwards; i++) { + debug("Local connections to %.200s:%d forwarded to remote " + "address %.200s:%d", + (options.local_forwards[i].listen_path != NULL) ? + options.local_forwards[i].listen_path : + (options.local_forwards[i].listen_host == NULL) ? + (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") : + options.local_forwards[i].listen_host, + options.local_forwards[i].listen_port, + (options.local_forwards[i].connect_path != NULL) ? + options.local_forwards[i].connect_path : + options.local_forwards[i].connect_host, + options.local_forwards[i].connect_port); + success += channel_setup_local_fwd_listener( + &options.local_forwards[i], &options.fwd_opts); + } + if (i > 0 && success != i && options.exit_on_forward_failure) + fatal("Could not request local forwarding."); + if (i > 0 && success == 0) + error("Could not request local forwarding."); + + /* Initiate remote TCP/IP port forwardings. */ + for (i = 0; i < options.num_remote_forwards; i++) { + debug("Remote connections from %.200s:%d forwarded to " + "local address %.200s:%d", + (options.remote_forwards[i].listen_path != NULL) ? + options.remote_forwards[i].listen_path : + (options.remote_forwards[i].listen_host == NULL) ? + "LOCALHOST" : options.remote_forwards[i].listen_host, + options.remote_forwards[i].listen_port, + (options.remote_forwards[i].connect_path != NULL) ? + options.remote_forwards[i].connect_path : + options.remote_forwards[i].connect_host, + options.remote_forwards[i].connect_port); + options.remote_forwards[i].handle = + channel_request_remote_forwarding( + &options.remote_forwards[i]); + if (options.remote_forwards[i].handle < 0) { + if (options.exit_on_forward_failure) + fatal("Could not request remote forwarding."); + else + logit("Warning: Could not request remote " + "forwarding."); + } else { + client_register_global_confirm(ssh_confirm_remote_forward, + &options.remote_forwards[i]); + } + } + + /* Initiate tunnel forwarding. */ + if (options.tun_open != SSH_TUNMODE_NO) { + if (client_request_tun_fwd(options.tun_open, + options.tun_local, options.tun_remote) == -1) { + if (options.exit_on_forward_failure) + fatal("Could not request tunnel forwarding."); + else + error("Could not request tunnel forwarding."); + } + } +} + +static void +check_agent_present(void) +{ + int r; + + if (options.forward_agent) { + /* Clear agent forwarding if we don't have an agent. */ + if ((r = ssh_get_authentication_socket(NULL)) != 0) { + options.forward_agent = 0; + if (r != SSH_ERR_AGENT_NOT_PRESENT) + debug("ssh_get_authentication_socket: %s", + ssh_err(r)); + } + } +} + +static int +ssh_session(void) +{ + int type; + int interactive = 0; + int have_tty = 0; + struct winsize ws; + char *cp; + const char *display; + + /* Enable compression if requested. */ + if (options.compression) { + debug("Requesting compression at level %d.", + options.compression_level); + + if (options.compression_level < 1 || + options.compression_level > 9) + fatal("Compression level must be from 1 (fast) to " + "9 (slow, best)."); + + /* Send the request. */ + packet_start(SSH_CMSG_REQUEST_COMPRESSION); + packet_put_int(options.compression_level); + packet_send(); + packet_write_wait(); + type = packet_read(); + if (type == SSH_SMSG_SUCCESS) + packet_start_compression(options.compression_level); + else if (type == SSH_SMSG_FAILURE) + logit("Warning: Remote host refused compression."); + else + packet_disconnect("Protocol error waiting for " + "compression response."); + } + /* Allocate a pseudo tty if appropriate. */ + if (tty_flag) { + debug("Requesting pty."); + + /* Start the packet. */ + packet_start(SSH_CMSG_REQUEST_PTY); + + /* Store TERM in the packet. There is no limit on the + length of the string. */ + cp = getenv("TERM"); + if (!cp) + cp = ""; + packet_put_cstring(cp); + + /* Store window size in the packet. */ + if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) + memset(&ws, 0, sizeof(ws)); + packet_put_int((u_int)ws.ws_row); + packet_put_int((u_int)ws.ws_col); + packet_put_int((u_int)ws.ws_xpixel); + packet_put_int((u_int)ws.ws_ypixel); + + /* Store tty modes in the packet. */ + tty_make_modes(fileno(stdin), NULL); + + /* Send the packet, and wait for it to leave. */ + packet_send(); + packet_write_wait(); + + /* Read response from the server. */ + type = packet_read(); + if (type == SSH_SMSG_SUCCESS) { + interactive = 1; + have_tty = 1; + } else if (type == SSH_SMSG_FAILURE) + logit("Warning: Remote host failed or refused to " + "allocate a pseudo tty."); + else + packet_disconnect("Protocol error waiting for pty " + "request response."); + } + /* Request X11 forwarding if enabled and DISPLAY is set. */ + display = getenv("DISPLAY"); + if (display == NULL && options.forward_x11) + debug("X11 forwarding requested but DISPLAY not set"); + if (options.forward_x11 && display != NULL) { + char *proto, *data; + /* Get reasonable local authentication information. */ + client_x11_get_proto(display, options.xauth_location, + options.forward_x11_trusted, + options.forward_x11_timeout, + &proto, &data); + /* Request forwarding with authentication spoofing. */ + debug("Requesting X11 forwarding with authentication " + "spoofing."); + x11_request_forwarding_with_spoofing(0, display, proto, + data, 0); + /* Read response from the server. */ + type = packet_read(); + if (type == SSH_SMSG_SUCCESS) { + interactive = 1; + } else if (type == SSH_SMSG_FAILURE) { + logit("Warning: Remote host denied X11 forwarding."); + } else { + packet_disconnect("Protocol error waiting for X11 " + "forwarding"); + } + } + /* Tell the packet module whether this is an interactive session. */ + packet_set_interactive(interactive, + options.ip_qos_interactive, options.ip_qos_bulk); + + /* Request authentication agent forwarding if appropriate. */ + check_agent_present(); + + if (options.forward_agent) { + debug("Requesting authentication agent forwarding."); + auth_request_forwarding(); + + /* Read response from the server. */ + type = packet_read(); + packet_check_eom(); + if (type != SSH_SMSG_SUCCESS) + logit("Warning: Remote host denied authentication agent forwarding."); + } + + /* Initiate port forwardings. */ + ssh_init_stdio_forwarding(); + ssh_init_forwarding(); + + /* Execute a local command */ + if (options.local_command != NULL && + options.permit_local_command) + ssh_local_cmd(options.local_command); + + /* + * If requested and we are not interested in replies to remote + * forwarding requests, then let ssh continue in the background. + */ + if (fork_after_authentication_flag) { + if (options.exit_on_forward_failure && + options.num_remote_forwards > 0) { + debug("deferring postauth fork until remote forward " + "confirmation received"); + } else + fork_postauth(); + } + + /* + * If a command was specified on the command line, execute the + * command now. Otherwise request the server to start a shell. + */ + if (buffer_len(&command) > 0) { + int len = buffer_len(&command); + if (len > 900) + len = 900; + debug("Sending command: %.*s", len, + (u_char *)buffer_ptr(&command)); + packet_start(SSH_CMSG_EXEC_CMD); + packet_put_string(buffer_ptr(&command), buffer_len(&command)); + packet_send(); + packet_write_wait(); + } else { + debug("Requesting shell."); + packet_start(SSH_CMSG_EXEC_SHELL); + packet_send(); + packet_write_wait(); + } + + /* Enter the interactive session. */ + return client_loop(have_tty, tty_flag ? + options.escape_char : SSH_ESCAPECHAR_NONE, 0); +} + +/* request pty/x11/agent/tcpfwd/shell for channel */ +static void +ssh_session2_setup(int id, int success, void *arg) +{ + extern char **environ; + const char *display; + int interactive = tty_flag; + + if (!success) + return; /* No need for error message, channels code sens one */ + + display = getenv("DISPLAY"); + if (display == NULL && options.forward_x11) + debug("X11 forwarding requested but DISPLAY not set"); + if (options.forward_x11 && display != NULL) { + char *proto, *data; + /* Get reasonable local authentication information. */ + client_x11_get_proto(display, options.xauth_location, + options.forward_x11_trusted, + options.forward_x11_timeout, &proto, &data); + /* Request forwarding with authentication spoofing. */ + debug("Requesting X11 forwarding with authentication " + "spoofing."); + x11_request_forwarding_with_spoofing(id, display, proto, + data, 1); + client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); + /* XXX exit_on_forward_failure */ + interactive = 1; + } + + check_agent_present(); + if (options.forward_agent) { + debug("Requesting authentication agent forwarding."); + channel_request_start(id, "auth-agent-req@openssh.com", 0); + packet_send(); + } + + /* Tell the packet module whether this is an interactive session. */ + packet_set_interactive(interactive, + options.ip_qos_interactive, options.ip_qos_bulk); + + client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), + NULL, fileno(stdin), &command, environ); +} + +/* open new channel for a session */ +static int +ssh_session2_open(void) +{ + Channel *c; + int window, packetmax, in, out, err; + + if (stdin_null_flag) { + in = open(_PATH_DEVNULL, O_RDONLY); + } else { + in = dup(STDIN_FILENO); + } + out = dup(STDOUT_FILENO); + err = dup(STDERR_FILENO); + + if (in < 0 || out < 0 || err < 0) + fatal("dup() in/out/err failed"); + + /* enable nonblocking unless tty */ + if (!isatty(in)) + set_nonblock(in); + if (!isatty(out)) + set_nonblock(out); + if (!isatty(err)) + set_nonblock(err); + + window = CHAN_SES_WINDOW_DEFAULT; + packetmax = CHAN_SES_PACKET_DEFAULT; + if (tty_flag) { + window >>= 1; + packetmax >>= 1; + } + c = channel_new( + "session", SSH_CHANNEL_OPENING, in, out, err, + window, packetmax, CHAN_EXTENDED_WRITE, + "client-session", /*nonblock*/0); + + debug3("ssh_session2_open: channel_new: %d", c->self); + + channel_send_open(c->self); + if (!no_shell_flag) + channel_register_open_confirm(c->self, + ssh_session2_setup, NULL); + + return c->self; +} + +static int +ssh_session2(void) +{ + int id = -1; + + /* XXX should be pre-session */ + if (!options.control_persist) + ssh_init_stdio_forwarding(); + ssh_init_forwarding(); + + /* Start listening for multiplex clients */ + muxserver_listen(); + + /* + * If we are in control persist mode and have a working mux listen + * socket, then prepare to background ourselves and have a foreground + * client attach as a control slave. + * NB. we must save copies of the flags that we override for + * the backgrounding, since we defer attachment of the slave until + * after the connection is fully established (in particular, + * async rfwd replies have been received for ExitOnForwardFailure). + */ + if (options.control_persist && muxserver_sock != -1) { + ostdin_null_flag = stdin_null_flag; + ono_shell_flag = no_shell_flag; + orequest_tty = options.request_tty; + otty_flag = tty_flag; + stdin_null_flag = 1; + no_shell_flag = 1; + tty_flag = 0; + if (!fork_after_authentication_flag) + need_controlpersist_detach = 1; + fork_after_authentication_flag = 1; + } + /* + * ControlPersist mux listen socket setup failed, attempt the + * stdio forward setup that we skipped earlier. + */ + if (options.control_persist && muxserver_sock == -1) + ssh_init_stdio_forwarding(); + + if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) + id = ssh_session2_open(); + else { + packet_set_interactive( + options.control_master == SSHCTL_MASTER_NO, + options.ip_qos_interactive, options.ip_qos_bulk); + } + + /* If we don't expect to open a new session, then disallow it */ + if (options.control_master == SSHCTL_MASTER_NO && + (datafellows & SSH_NEW_OPENSSH)) { + debug("Requesting no-more-sessions@openssh.com"); + packet_start(SSH2_MSG_GLOBAL_REQUEST); + packet_put_cstring("no-more-sessions@openssh.com"); + packet_put_char(0); + packet_send(); + } + + /* Execute a local command */ + if (options.local_command != NULL && + options.permit_local_command) + ssh_local_cmd(options.local_command); + + /* + * If requested and we are not interested in replies to remote + * forwarding requests, then let ssh continue in the background. + */ + if (fork_after_authentication_flag) { + if (options.exit_on_forward_failure && + options.num_remote_forwards > 0) { + debug("deferring postauth fork until remote forward " + "confirmation received"); + } else + fork_postauth(); + } + + return client_loop(tty_flag, tty_flag ? + options.escape_char : SSH_ESCAPECHAR_NONE, id); +} + +static void +load_public_identity_files(void) +{ + char *filename, *cp, thishost[NI_MAXHOST]; + char *pwdir = NULL, *pwname = NULL; + int i = 0; + Key *public; + struct passwd *pw; + u_int n_ids; + char *identity_files[SSH_MAX_IDENTITY_FILES]; + Key *identity_keys[SSH_MAX_IDENTITY_FILES]; +#ifdef ENABLE_PKCS11 + Key **keys; + int nkeys; +#endif /* PKCS11 */ + + n_ids = 0; + memset(identity_files, 0, sizeof(identity_files)); + memset(identity_keys, 0, sizeof(identity_keys)); + +#ifdef ENABLE_PKCS11 + if (options.pkcs11_provider != NULL && + options.num_identity_files < SSH_MAX_IDENTITY_FILES && + (pkcs11_init(!options.batch_mode) == 0) && + (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, + &keys)) > 0) { + for (i = 0; i < nkeys; i++) { + if (n_ids >= SSH_MAX_IDENTITY_FILES) { + key_free(keys[i]); + continue; + } + identity_keys[n_ids] = keys[i]; + identity_files[n_ids] = + xstrdup(options.pkcs11_provider); /* XXX */ + n_ids++; + } + free(keys); + } +#endif /* ENABLE_PKCS11 */ + if ((pw = getpwuid(original_real_uid)) == NULL) + fatal("load_public_identity_files: getpwuid failed"); + pwname = xstrdup(pw->pw_name); + pwdir = xstrdup(pw->pw_dir); + if (gethostname(thishost, sizeof(thishost)) == -1) + fatal("load_public_identity_files: gethostname: %s", + strerror(errno)); + for (i = 0; i < options.num_identity_files; i++) { + if (n_ids >= SSH_MAX_IDENTITY_FILES || + strcasecmp(options.identity_files[i], "none") == 0) { + free(options.identity_files[i]); + continue; + } + cp = tilde_expand_filename(options.identity_files[i], + original_real_uid); + filename = percent_expand(cp, "d", pwdir, + "u", pwname, "l", thishost, "h", host, + "r", options.user, (char *)NULL); + free(cp); + public = key_load_public(filename, NULL); + debug("identity file %s type %d", filename, + public ? public->type : -1); + free(options.identity_files[i]); + identity_files[n_ids] = filename; + identity_keys[n_ids] = public; + + if (++n_ids >= SSH_MAX_IDENTITY_FILES) + continue; + + /* Try to add the certificate variant too */ + xasprintf(&cp, "%s-cert", filename); + public = key_load_public(cp, NULL); + debug("identity file %s type %d", cp, + public ? public->type : -1); + if (public == NULL) { + free(cp); + continue; + } + if (!key_is_cert(public)) { + debug("%s: key %s type %s is not a certificate", + __func__, cp, key_type(public)); + key_free(public); + free(cp); + continue; + } + identity_keys[n_ids] = public; + /* point to the original path, most likely the private key */ + identity_files[n_ids] = xstrdup(filename); + n_ids++; + } + options.num_identity_files = n_ids; + memcpy(options.identity_files, identity_files, sizeof(identity_files)); + memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); + + explicit_bzero(pwname, strlen(pwname)); + free(pwname); + explicit_bzero(pwdir, strlen(pwdir)); + free(pwdir); +} + +static void +main_sigchld_handler(int sig) +{ + int save_errno = errno; + pid_t pid; + int status; + + while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || + (pid < 0 && errno == EINTR)) + ; + + signal(sig, main_sigchld_handler); + errno = save_errno; +} |
