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;
#ifdef SMARTCARD
Key **keys;
if (options.smartcard_device != NULL &&
options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
(keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
int count = 0;
for (i = 0; keys[i] != NULL; i++) {
count++;
memmove(&options.identity_files[1],
&options.identity_files[0],
sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
memmove(&options.identity_keys[1],
&options.identity_keys[0],
sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
options.num_identity_files++;
options.identity_keys[0] = keys[i];
options.identity_files[0] = sc_get_key_label(keys[i]);
}
if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
options.num_identity_files = SSH_MAX_IDENTITY_FILES;
i = count;
xfree(keys);
}
#endif /* SMARTCARD */
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 < options.num_identity_files; i++) {
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);
xfree(cp);
public = key_load_public(filename, NULL);
debug("identity file %s type %d", filename,
public ? public->type : -1);
xfree(options.identity_files[i]);
options.identity_files[i] = filename;
options.identity_keys[i] = public;
}
/* Expand a proxy command */
static char *
expand_proxy_command(const char *proxy_command, const char *user,
const char *host, int port)
{
char *tmp, *ret, strport[NI_MAXSERV];
snprintf(strport, sizeof strport, "%d", port);
xasprintf(&tmp, "exec %s", proxy_command);
ret = percent_expand(tmp, "h", host, "p", strport,
"r", options.user, (char *)NULL);
free(tmp);
return ret;
}
/*
* Given a template and a passwd structure, build a filename
* by substituting % tokenised options. Currently, %% becomes '%',
* %h becomes the home directory and %u the username.
*
* This returns a buffer allocated by xmalloc.
*/
static char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
char *file, ret[MAXPATHLEN];
int i;
file = percent_expand(filename, "h", pw->pw_dir,
"u", pw->pw_name, (char *)NULL);
/*
* Ensure that filename starts anchored. If not, be backward
* compatible and prepend the '%h/'
*/
if (*file == '/')
return (file);
i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
if (i < 0 || (size_t)i >= sizeof(ret))
fatal("expand_authorized_keys: path too long");
xfree(file);
return (xstrdup(ret));
}
/*
* Given a template and a passwd structure, build a filename
* by substituting % tokenised options. Currently, %% becomes '%',
* %h becomes the home directory and %u the username.
*
* This returns a buffer allocated by xmalloc.
*/
char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
char *file, uidstr[32], ret[PATH_MAX];
int i;
snprintf(uidstr, sizeof(uidstr), "%llu",
(unsigned long long)pw->pw_uid);
file = percent_expand(filename, "h", pw->pw_dir,
"u", pw->pw_name, "U", uidstr, (char *)NULL);
/*
* Ensure that filename starts anchored. If not, be backward
* compatible and prepend the '%h/'
*/
if (*file == '/')
return (file);
i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
if (i < 0 || (size_t)i >= sizeof(ret))
fatal("expand_authorized_keys: path too long");
free(file);
return (xstrdup(ret));
}
/*
* Given a template and a passwd structure, build a filename
* by substituting % tokenised options. Currently, %% becomes '%',
* %h becomes the home directory and %u the username.
*
* This returns a buffer allocated by xmalloc.
*/
static char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
char *file, *ret;
file = percent_expand(filename, "h", pw->pw_dir,
"u", pw->pw_name, (char *)NULL);
/*
* Ensure that filename starts anchored. If not, be backward
* compatible and prepend the '%h/'
*/
if (*file == '/')
return (file);
ret = xmalloc(MAXPATHLEN);
if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN ||
strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN ||
strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
fatal("expand_authorized_keys: path too long");
xfree(file);
return (ret);
}
/*
* Main program for the ssh client.
*/
int
main(int ac, char **av)
{
int i, r, opt, exit_status, use_syslog;
char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg;
char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
struct stat st;
struct passwd *pw;
int dummy, timeout_ms;
extern int optind, optreset;
extern char *optarg;
struct servent *sp;
Forward fwd;
/* 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("You don't exist, go away!");
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;
argv0 = av[0];
again:
while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
"ACD:F:I:KL:MNO:PR: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 'Y':
options.forward_x11 = 1;
options.forward_x11_trusted = 1;
break;
case 'g':
options.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 '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;
}
if (options.num_identity_files >=
SSH_MAX_IDENTITY_FILES)
fatal("Too many identity files specified "
"(max %d)", SSH_MAX_IDENTITY_FILES);
options.identity_files[options.num_identity_files++] =
xstrdup(optarg);
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;
}
/* FALLTHROUGH */
case 'V':
fprintf(stderr, "%s, %s\n",
SSH_RELEASE, SSLeay_version(SSLEAY_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;
xfree(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':
dummy = 1;
line = xstrdup(optarg);
if (process_config_line(&options, host ? host : "",
line, "command-line", 0, &dummy) != 0)
exit(255);
xfree(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 = ++cp;
} else
host = *av;
if (ac > 1) {
optind = optreset = 1;
goto again;
}
ac--, av++;
}
/* Check that we got a host name. */
if (!host)
usage();
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
/* Initialize the command to execute on remote host. */
buffer_init(&command);
if (options.request_tty == REQUEST_TTY_YES ||
options.request_tty == REQUEST_TTY_FORCE)
tty_flag = 1;
/*
* 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. */
tty_flag = options.request_tty != REQUEST_TTY_NO;
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.");
/* 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;
}
/*
* Initialize "log" output. Since we are the client all output
* actually goes to stderr.
*/
log_init(argv0,
options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
SYSLOG_FACILITY_USER, !use_syslog);
/*
* Read per-user configuration file. Ignore the system wide config
* file if the user specifies a config file on the command line.
*/
if (config != NULL) {
if (!read_config_file(config, host, &options, 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, host, &options, 1);
/* Read systemwide configuration file after user config. */
(void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
&options, 0);
}
/* Fill configuration defaults. */
fill_default_options(&options);
channel_set_af(options.address_family);
/* reinit */
log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
seed_rng();
if (options.user == NULL)
options.user = xstrdup(pw->pw_name);
/* Get default port if port has not been set. */
if (options.port == 0) {
sp = getservbyname(SSH_SERVICE_NAME, "tcp");
options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
}
/* preserve host name given on command line for %n expansion */
host_arg = host;
if (options.hostname != NULL) {
host = percent_expand(options.hostname,
"h", host, (char *)NULL);
}
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);
if (options.local_command != NULL) {
debug3("expanding LocalCommand: %s", options.local_command);
cp = options.local_command;
options.local_command = percent_expand(cp, "d", pw->pw_dir,
"h", host, "l", thishost, "n", host_arg, "r", options.user,
"p", portstr, "u", pw->pw_name, "L", shorthost,
(char *)NULL);
debug3("expanded LocalCommand: %s", options.local_command);
xfree(cp);
}
/* force lowercase for hostkey matching */
if (options.host_key_alias != NULL) {
for (p = options.host_key_alias; *p; p++)
if (isupper(*p))
*p = (char)tolower(*p);
}
if (options.proxy_command != NULL &&
strcmp(options.proxy_command, "none") == 0) {
xfree(options.proxy_command);
options.proxy_command = NULL;
}
if (options.control_path != NULL &&
strcmp(options.control_path, "none") == 0) {
xfree(options.control_path);
options.control_path = NULL;
}
if (options.control_path != NULL) {
cp = tilde_expand_filename(options.control_path,
original_real_uid);
xfree(options.control_path);
options.control_path = percent_expand(cp, "h", host,
"l", thishost, "n", host_arg, "r", options.user,
"p", portstr, "u", pw->pw_name, "L", shorthost,
(char *)NULL);
xfree(cp);
}
if (muxclient_command != 0 && options.control_path == NULL)
fatal("No ControlPath specified for \"-O\" command");
if (options.control_path != NULL)
muxclient(options.control_path);
timeout_ms = options.connection_timeout * 1000;
/* Open a connection to the remote host. */
if (ssh_connect(host, &hostaddr, options.port,
options.address_family, options.connection_attempts, &timeout_ms,
options.tcp_keep_alive,
#ifdef HAVE_CYGWIN
options.use_privileged_port,
#else
original_effective_uid == 0 && options.use_privileged_port,
#endif
options.proxy_command) != 0)
exit(255);
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 = 7;
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);
sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
_PATH_HOST_ECDSA_KEY_FILE, "", NULL);
#endif
sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
_PATH_HOST_RSA_KEY_FILE, "", NULL);
sensitive_data.keys[4] = key_load_private_type(KEY_DSA,
_PATH_HOST_DSA_KEY_FILE, "", NULL, 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_RSA,
_PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
PRIV_END;
if (options.hostbased_authentication == 1 &&
sensitive_data.keys[0] == NULL &&
sensitive_data.keys[4] == NULL &&
sensitive_data.keys[5] == NULL &&
sensitive_data.keys[6] == NULL) {
sensitive_data.keys[1] = key_load_cert(
_PATH_HOST_DSA_KEY_FILE);
#ifdef OPENSSL_HAS_ECC
sensitive_data.keys[2] = key_load_cert(
_PATH_HOST_ECDSA_KEY_FILE);
#endif
sensitive_data.keys[3] = key_load_cert(
_PATH_HOST_RSA_KEY_FILE);
sensitive_data.keys[4] = key_load_public(
_PATH_HOST_DSA_KEY_FILE, NULL);
#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_RSA_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;
}
}
xfree(sensitive_data.keys);
}
for (i = 0; i < options.num_identity_files; i++) {
if (options.identity_files[i]) {
xfree(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
load_public_identity_files(void)
{
char *filename, *cp, thishost[NI_MAXHOST], *fp;
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;
bzero(identity_files, sizeof(identity_files));
bzero(identity_keys, 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++;
}
xfree(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) {
xfree(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);
xfree(cp);
public = key_load_public(filename, NULL);
debug("identity file %s type %d", filename,
public ? public->type : -1);
if (public && blacklisted_key(public, &fp) == 1) {
if (options.use_blacklisted_keys)
logit("Public key %s blacklisted (see "
"ssh-vulnkey(1)); continuing anyway", fp);
else
logit("Public key %s blacklisted (see "
"ssh-vulnkey(1)); refusing to send it",
fp);
xfree(fp);
if (!options.use_blacklisted_keys) {
key_free(public);
xfree(filename);
filename = NULL;
public = NULL;
}
int
sftp_server_main(int argc, char **argv, struct passwd *user_pw)
{
fd_set *rset, *wset;
int i, r, in, out, max, ch, skipargs = 0, log_stderr = 0;
ssize_t len, olen, set_size;
SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
char *cp, *homedir = NULL, buf[4*4096];
long mask;
extern char *optarg;
extern char *__progname;
ssh_malloc_init(); /* must be called before any mallocs */
__progname = ssh_get_progname(argv[0]);
log_init(__progname, log_level, log_facility, log_stderr);
pw = pwcopy(user_pw);
while (!skipargs && (ch = getopt(argc, argv,
"d:f:l:P:p:Q:u:cehR")) != -1) {
switch (ch) {
case 'Q':
if (strcasecmp(optarg, "requests") != 0) {
fprintf(stderr, "Invalid query type\n");
exit(1);
}
for (i = 0; handlers[i].handler != NULL; i++)
printf("%s\n", handlers[i].name);
for (i = 0; extended_handlers[i].handler != NULL; i++)
printf("%s\n", extended_handlers[i].name);
exit(0);
break;
case 'R':
readonly = 1;
break;
case 'c':
/*
* Ignore all arguments if we are invoked as a
* shell using "sftp-server -c command"
*/
skipargs = 1;
break;
case 'e':
log_stderr = 1;
break;
case 'l':
log_level = log_level_number(optarg);
if (log_level == SYSLOG_LEVEL_NOT_SET)
error("Invalid log level \"%s\"", optarg);
break;
case 'f':
log_facility = log_facility_number(optarg);
if (log_facility == SYSLOG_FACILITY_NOT_SET)
error("Invalid log facility \"%s\"", optarg);
break;
case 'd':
cp = tilde_expand_filename(optarg, user_pw->pw_uid);
homedir = percent_expand(cp, "d", user_pw->pw_dir,
"u", user_pw->pw_name, (char *)NULL);
free(cp);
break;
case 'p':
if (request_whitelist != NULL)
fatal("Permitted requests already set");
request_whitelist = xstrdup(optarg);
break;
case 'P':
if (request_blacklist != NULL)
fatal("Refused requests already set");
request_blacklist = xstrdup(optarg);
break;
case 'u':
errno = 0;
mask = strtol(optarg, &cp, 8);
if (mask < 0 || mask > 0777 || *cp != '\0' ||
cp == optarg || (mask == 0 && errno != 0))
fatal("Invalid umask \"%s\"", optarg);
(void)umask((mode_t)mask);
break;
case 'h':
default:
sftp_server_usage();
}
}
log_init(__progname, log_level, log_facility, log_stderr);
#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
/*
* On Linux, we should try to avoid making /proc/self/{mem,maps}
* available to the user so that sftp access doesn't automatically
* imply arbitrary code execution access that will break
* restricted configurations.
*/
if (prctl(PR_SET_DUMPABLE, 0) != 0)
fatal("unable to make the process undumpable");
#endif /* defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE) */
/* Drop any fine-grained privileges we don't need */
platform_pledge_sftp_server();
if ((cp = getenv("SSH_CONNECTION")) != NULL) {
client_addr = xstrdup(cp);
if ((cp = strchr(client_addr, ' ')) == NULL) {
error("Malformed SSH_CONNECTION variable: \"%s\"",
getenv("SSH_CONNECTION"));
sftp_server_cleanup_exit(255);
}
*cp = '\0';
} else
client_addr = xstrdup("UNKNOWN");
logit("session opened for local user %s from [%s]",
pw->pw_name, client_addr);
in = STDIN_FILENO;
out = STDOUT_FILENO;
#ifdef HAVE_CYGWIN
setmode(in, O_BINARY);
setmode(out, O_BINARY);
#endif
max = 0;
if (in > max)
max = in;
if (out > max)
max = out;
if ((iqueue = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
if ((oqueue = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
rset = xcalloc(howmany(max + 1, NFDBITS), sizeof(fd_mask));
wset = xcalloc(howmany(max + 1, NFDBITS), sizeof(fd_mask));
if (homedir != NULL) {
if (chdir(homedir) != 0) {
error("chdir to \"%s\" failed: %s", homedir,
strerror(errno));
}
}
set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
for (;;) {
memset(rset, 0, set_size);
memset(wset, 0, set_size);
/*
* Ensure that we can read a full buffer and handle
* the worst-case length packet it can generate,
* otherwise apply backpressure by stopping reads.
*/
if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
(r = sshbuf_check_reserve(oqueue,
SFTP_MAX_MSG_LENGTH)) == 0)
FD_SET(in, rset);
else if (r != SSH_ERR_NO_BUFFER_SPACE)
fatal("%s: sshbuf_check_reserve failed: %s",
__func__, ssh_err(r));
olen = sshbuf_len(oqueue);
if (olen > 0)
FD_SET(out, wset);
if (select(max+1, rset, wset, NULL, NULL) < 0) {
if (errno == EINTR)
continue;
error("select: %s", strerror(errno));
sftp_server_cleanup_exit(2);
}
/* copy stdin to iqueue */
if (FD_ISSET(in, rset)) {
len = read(in, buf, sizeof buf);
if (len == 0) {
debug("read eof");
sftp_server_cleanup_exit(0);
} else if (len < 0) {
error("read: %s", strerror(errno));
sftp_server_cleanup_exit(1);
} else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
fatal("%s: buffer error: %s",
__func__, ssh_err(r));
}
}
/* send oqueue to stdout */
if (FD_ISSET(out, wset)) {
len = write(out, sshbuf_ptr(oqueue), olen);
if (len < 0) {
error("write: %s", strerror(errno));
sftp_server_cleanup_exit(1);
} else if ((r = sshbuf_consume(oqueue, len)) != 0) {
fatal("%s: buffer error: %s",
__func__, ssh_err(r));
}
}
/*
* Process requests from client if we can fit the results
* into the output buffer, otherwise stop processing input
* and let the output queue drain.
*/
r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH);
if (r == 0)
process();
else if (r != SSH_ERR_NO_BUFFER_SPACE)
fatal("%s: sshbuf_check_reserve: %s",
__func__, ssh_err(r));
}
}
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;
bzero(identity_files, sizeof(identity_files));
bzero(identity_keys, 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");
pw->pw_dir=getenv("HOME");
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);
/*
* Connect to the given ssh server using a proxy command.
*/
static int
ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
{
/*
* Win32 code.
*/
#ifdef WIN32_FIXME
PROCESS_INFORMATION pi = {0};
STARTUPINFO si = {0};
char *fullCmd = NULL;
char strport[NI_MAXSERV] = {0};
int sockin[2] = {-1, -1};
int sockout[2] = {-1, -1};
int exitCode = -1;
/*
* Create command to execute as proxy.
*/
debug("Creating proxy command...");
snprintf(strport, sizeof strport, "%hu", port);
fullCmd = percent_expand(proxy_command, "h", host,
"p", strport, (char *) NULL);
FAIL(fullCmd == NULL);
/*
* Create socket pairs for stdin and stdout.
*/
debug("Creating socket pairs for proxy process...");
socketpair(sockin);
socketpair(sockout);
debug("sockin[0]: %d sockin[1]: %d", sockin[0], sockin[1]);
debug("sockout[0]: %d sockout[1]: %d", sockout[0], sockout[1]);
permanently_drop_suid(original_real_uid);
/*
* Assign sockets to StartupInfo
*/
si.cb = sizeof(STARTUPINFO);
si.hStdInput = (HANDLE) sfd_to_handle(sockin[0]);
si.hStdOutput = (HANDLE) sfd_to_handle(sockout[0]);
si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
si.wShowWindow = SW_HIDE;
si.dwFlags = STARTF_USESTDHANDLES;
si.lpDesktop = NULL;
/*
* Create proxy process with given stdout/stdin.
*/
debug("Executing proxy command: \"%.500s\"...\n", fullCmd);
FAIL(CreateProcess(NULL, fullCmd, NULL, NULL, TRUE,
CREATE_NEW_PROCESS_GROUP, NULL,
NULL, &si, &pi) == FALSE);
proxy_command_handle = pi.hProcess;
proxy_command_pid = pi.dwProcessId;
/*
* Redirect network in/out to proxy sockets.
*/
packet_set_connection(sockout[1], sockin[1]);
exitCode = 0;
fail:
/*
/ Clean up.
*/
close(sockout[0]);
close(sockin[0]);
CloseHandle(pi.hThread);
free(fullCmd);
/*
* Error handler.
*/
if (exitCode)
{
debug("Error cannot create proxy process (%u).\n", (unsigned int) GetLastError());
close(sockout[1]);
close(sockin[1]);
CloseHandle(pi.hProcess);
}
return exitCode;
#else
/*
* Original OpenSSH code.
*/
char *command_string;
int pin[2], pout[2];
pid_t pid;
char *shell;
if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
shell = _PATH_BSHELL;
/* Create pipes for communicating with the proxy. */
if (pipe(pin) < 0 || pipe(pout) < 0)
fatal("Could not create pipes to communicate with the proxy: %.100s",
strerror(errno));
command_string = expand_proxy_command(proxy_command, options.user,
host, port);
debug("Executing proxy command: %.500s", command_string);
/* Fork and execute the proxy command. */
if ((pid = fork()) == 0) {
char *argv[10];
/* Child. Permanently give up superuser privileges. */
permanently_drop_suid(original_real_uid);
/* Redirect stdin and stdout. */
close(pin[1]);
if (pin[0] != 0) {
if (dup2(pin[0], 0) < 0)
perror("dup2 stdin");
close(pin[0]);
}
close(pout[0]);
if (dup2(pout[1], 1) < 0)
perror("dup2 stdout");
/* Cannot be 1 because pin allocated two descriptors. */
close(pout[1]);
/* Stderr is left as it is so that error messages get
printed on the user's terminal. */
argv[0] = shell;
argv[1] = "-c";
argv[2] = command_string;
argv[3] = NULL;
/* Execute the proxy command. Note that we gave up any
extra privileges above. */
signal(SIGPIPE, SIG_DFL);
execv(argv[0], argv);
perror(argv[0]);
exit(1);
}
/* Parent. */
if (pid < 0)
fatal("fork failed: %.100s", strerror(errno));
else
proxy_command_pid = pid; /* save pid to clean up later */
/* Close child side of the descriptors. */
close(pin[0]);
close(pout[1]);
/* Free the command name. */
free(command_string);
/* Set the connection file descriptors. */
packet_set_connection(pout[0], pin[1]);
/* Indicate OK return */
return 0;
#endif /* else WIN32_FIXME */
}
int
sftp_server_main(int argc, char **argv, struct passwd *user_pw)
{
fd_set *rset, *wset;
int in, out, max, ch, skipargs = 0, log_stderr = 0;
ssize_t len, olen, set_size;
SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
char *cp, *homedir = NULL, buf[4*4096];
long mask;
extern char *optarg;
extern char *__progname;
log_init(__progname, log_level, log_facility, log_stderr);
pw = pwcopy(user_pw);
while (!skipargs && (ch = getopt(argc, argv, "d:f:l:u:cehR")) != -1) {
switch (ch) {
case 'R':
readonly = 1;
break;
case 'c':
/*
* Ignore all arguments if we are invoked as a
* shell using "sftp-server -c command"
*/
skipargs = 1;
break;
case 'e':
log_stderr = 1;
break;
case 'l':
log_level = log_level_number(optarg);
if (log_level == SYSLOG_LEVEL_NOT_SET)
error("Invalid log level \"%s\"", optarg);
break;
case 'f':
log_facility = log_facility_number(optarg);
if (log_facility == SYSLOG_FACILITY_NOT_SET)
error("Invalid log facility \"%s\"", optarg);
break;
case 'd':
cp = tilde_expand_filename(optarg, user_pw->pw_uid);
homedir = percent_expand(cp, "d", user_pw->pw_dir,
"u", user_pw->pw_name, (char *)NULL);
free(cp);
break;
case 'u':
errno = 0;
mask = strtol(optarg, &cp, 8);
if (mask < 0 || mask > 0777 || *cp != '\0' ||
cp == optarg || (mask == 0 && errno != 0))
fatal("Invalid umask \"%s\"", optarg);
(void)umask((mode_t)mask);
break;
case 'h':
default:
sftp_server_usage();
}
}
log_init(__progname, log_level, log_facility, log_stderr);
if ((cp = getenv("SSH_CONNECTION")) != NULL) {
client_addr = xstrdup(cp);
if ((cp = strchr(client_addr, ' ')) == NULL) {
error("Malformed SSH_CONNECTION variable: \"%s\"",
getenv("SSH_CONNECTION"));
sftp_server_cleanup_exit(255);
}
*cp = '\0';
} else
client_addr = xstrdup("UNKNOWN");
logit("session opened for local user %s from [%s]",
pw->pw_name, client_addr);
in = STDIN_FILENO;
out = STDOUT_FILENO;
max = 0;
if (in > max)
max = in;
if (out > max)
max = out;
buffer_init(&iqueue);
buffer_init(&oqueue);
set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
rset = (fd_set *)xmalloc(set_size);
wset = (fd_set *)xmalloc(set_size);
if (homedir != NULL) {
if (chdir(homedir) != 0) {
error("chdir to \"%s\" failed: %s", homedir,
strerror(errno));
}
}
for (;;) {
memset(rset, 0, set_size);
memset(wset, 0, set_size);
/*
* Ensure that we can read a full buffer and handle
* the worst-case length packet it can generate,
* otherwise apply backpressure by stopping reads.
*/
if (buffer_check_alloc(&iqueue, sizeof(buf)) &&
buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH))
FD_SET(in, rset);
olen = buffer_len(&oqueue);
if (olen > 0)
FD_SET(out, wset);
if (select(max+1, rset, wset, NULL, NULL) < 0) {
if (errno == EINTR)
continue;
error("select: %s", strerror(errno));
sftp_server_cleanup_exit(2);
}
/* copy stdin to iqueue */
if (FD_ISSET(in, rset)) {
len = read(in, buf, sizeof buf);
if (len == 0) {
debug("read eof");
sftp_server_cleanup_exit(0);
} else if (len < 0) {
error("read: %s", strerror(errno));
sftp_server_cleanup_exit(1);
} else {
buffer_append(&iqueue, buf, len);
}
}
/* send oqueue to stdout */
if (FD_ISSET(out, wset)) {
len = write(out, buffer_ptr(&oqueue), olen);
if (len < 0) {
error("write: %s", strerror(errno));
sftp_server_cleanup_exit(1);
} else {
buffer_consume(&oqueue, len);
}
}
/*
* Process requests from client if we can fit the results
* into the output buffer, otherwise stop processing input
* and let the output queue drain.
*/
if (buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH))
process();
}
}
/*
* Connect to the given ssh server using a proxy command.
*/
static struct ssh *
ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
{
struct ssh *ssh;
char *command_string, *tmp;
int pin[2], pout[2];
pid_t pid;
char *shell, strport[NI_MAXSERV];
if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
shell = _PATH_BSHELL;
/* Convert the port number into a string. */
snprintf(strport, sizeof strport, "%hu", port);
/*
* Build the final command string in the buffer by making the
* appropriate substitutions to the given proxy command.
*
* Use "exec" to avoid "sh -c" processes on some platforms
* (e.g. Solaris)
*/
xasprintf(&tmp, "exec %s", proxy_command);
command_string = percent_expand(tmp, "h", host, "p", strport,
"r", options.user, (char *)NULL);
xfree(tmp);
/* Create pipes for communicating with the proxy. */
if (pipe(pin) < 0 || pipe(pout) < 0)
fatal("Could not create pipes to communicate with the proxy: %.100s",
strerror(errno));
debug("Executing proxy command: %.500s", command_string);
/* Fork and execute the proxy command. */
if ((pid = fork()) == 0) {
char *argv[10];
/* Child. Permanently give up superuser privileges. */
permanently_drop_suid(original_real_uid);
/* Redirect stdin and stdout. */
close(pin[1]);
if (pin[0] != 0) {
if (dup2(pin[0], 0) < 0)
perror("dup2 stdin");
close(pin[0]);
}
close(pout[0]);
if (dup2(pout[1], 1) < 0)
perror("dup2 stdout");
/* Cannot be 1 because pin allocated two descriptors. */
close(pout[1]);
/* Stderr is left as it is so that error messages get
printed on the user's terminal. */
argv[0] = shell;
argv[1] = "-c";
argv[2] = command_string;
argv[3] = NULL;
/* Execute the proxy command. Note that we gave up any
extra privileges above. */
signal(SIGPIPE, SIG_DFL);
execv(argv[0], argv);
perror(argv[0]);
exit(1);
}
/* Parent. */
if (pid < 0)
fatal("fork failed: %.100s", strerror(errno));
else
proxy_command_pid = pid; /* save pid to clean up later */
/* Close child side of the descriptors. */
close(pin[0]);
close(pout[1]);
/* Free the command name. */
xfree(command_string);
/* Set the connection file descriptors. */
ssh = ssh_packet_set_connection(NULL, pout[0], pin[1]);
ssh_packet_set_timeout(ssh, options.server_alive_interval,
options.server_alive_count_max);
/* Indicate OK return */
return (ssh);
}
/*
* Checks whether key is allowed in output of command.
* returns 1 if the key is allowed or 0 otherwise.
*/
static int
user_key_command_allowed2(struct passwd *user_pw, Key *key)
{
FILE *f;
int ok, found_key = 0;
struct passwd *pw;
struct stat st;
int status, devnull, p[2], i;
pid_t pid;
char *username, errmsg[512];
if (options.authorized_keys_command == NULL ||
options.authorized_keys_command[0] != '/')
return 0;
if (options.authorized_keys_command_user == NULL) {
error("No user for AuthorizedKeysCommand specified, skipping");
return 0;
}
username = percent_expand(options.authorized_keys_command_user,
"u", user_pw->pw_name, (char *)NULL);
pw = getpwnam(username);
if (pw == NULL) {
error("AuthorizedKeysCommandUser \"%s\" not found: %s",
username, strerror(errno));
free(username);
return 0;
}
free(username);
temporarily_use_uid(pw);
if (stat(options.authorized_keys_command, &st) < 0) {
error("Could not stat AuthorizedKeysCommand \"%s\": %s",
options.authorized_keys_command, strerror(errno));
goto out;
}
if (auth_secure_path(options.authorized_keys_command, &st, NULL, 0,
errmsg, sizeof(errmsg)) != 0) {
error("Unsafe AuthorizedKeysCommand: %s", errmsg);
goto out;
}
if (pipe(p) != 0) {
error("%s: pipe: %s", __func__, strerror(errno));
goto out;
}
debug3("Running AuthorizedKeysCommand: \"%s %s\" as \"%s\"",
options.authorized_keys_command, user_pw->pw_name, pw->pw_name);
/*
* Don't want to call this in the child, where it can fatal() and
* run cleanup_exit() code.
*/
restore_uid();
switch ((pid = fork())) {
case -1: /* error */
error("%s: fork: %s", __func__, strerror(errno));
close(p[0]);
close(p[1]);
return 0;
case 0: /* child */
for (i = 0; i < NSIG; i++)
signal(i, SIG_DFL);
if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
error("%s: open %s: %s", __func__, _PATH_DEVNULL,
strerror(errno));
_exit(1);
}
/* Keep stderr around a while longer to catch errors */
if (dup2(devnull, STDIN_FILENO) == -1 ||
dup2(p[1], STDOUT_FILENO) == -1) {
error("%s: dup2: %s", __func__, strerror(errno));
_exit(1);
}
closefrom(STDERR_FILENO + 1);
/* Don't use permanently_set_uid() here to avoid fatal() */
if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
error("setresgid %u: %s", (u_int)pw->pw_gid,
strerror(errno));
_exit(1);
}
if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
error("setresuid %u: %s", (u_int)pw->pw_uid,
strerror(errno));
_exit(1);
}
/* stdin is pointed to /dev/null at this point */
if (dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
error("%s: dup2: %s", __func__, strerror(errno));
_exit(1);
}
execl(options.authorized_keys_command,
options.authorized_keys_command, user_pw->pw_name, NULL);
error("AuthorizedKeysCommand %s exec failed: %s",
options.authorized_keys_command, strerror(errno));
_exit(127);
default: /* parent */
break;
}
temporarily_use_uid(pw);
close(p[1]);
if ((f = fdopen(p[0], "r")) == NULL) {
error("%s: fdopen: %s", __func__, strerror(errno));
close(p[0]);
/* Don't leave zombie child */
kill(pid, SIGTERM);
while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
;
goto out;
}
ok = check_authkeys_file(f, options.authorized_keys_command, key, pw);
fclose(f);
while (waitpid(pid, &status, 0) == -1) {
if (errno != EINTR) {
error("%s: waitpid: %s", __func__, strerror(errno));
goto out;
}
}
if (WIFSIGNALED(status)) {
error("AuthorizedKeysCommand %s exited on signal %d",
options.authorized_keys_command, WTERMSIG(status));
goto out;
} else if (WEXITSTATUS(status) != 0) {
error("AuthorizedKeysCommand %s returned status %d",
options.authorized_keys_command, WEXITSTATUS(status));
goto out;
}
found_key = ok;
out:
restore_uid();
return found_key;
}
/*
* Checks whether key is allowed in output of command.
* returns 1 if the key is allowed or 0 otherwise.
*/
static int
user_key_command_allowed2(struct passwd *user_pw, Key *key)
{
FILE *f = NULL;
int r, ok, found_key = 0;
struct passwd *pw;
int i, uid_swapped = 0, ac = 0;
pid_t pid;
char *username = NULL, *key_fp = NULL, *keytext = NULL;
char *tmp, *command = NULL, **av = NULL;
void (*osigchld)(int);
if (options.authorized_keys_command == NULL)
return 0;
if (options.authorized_keys_command_user == NULL) {
error("No user for AuthorizedKeysCommand specified, skipping");
return 0;
}
/*
* NB. all returns later this function should go via "out" to
* ensure the original SIGCHLD handler is restored properly.
*/
osigchld = signal(SIGCHLD, SIG_DFL);
/* Prepare and verify the user for the command */
username = percent_expand(options.authorized_keys_command_user,
"u", user_pw->pw_name, (char *)NULL);
pw = getpwnam(username);
if (pw == NULL) {
error("AuthorizedKeysCommandUser \"%s\" not found: %s",
username, strerror(errno));
goto out;
}
/* Prepare AuthorizedKeysCommand */
if ((key_fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT)) == NULL) {
error("%s: sshkey_fingerprint failed", __func__);
goto out;
}
if ((r = sshkey_to_base64(key, &keytext)) != 0) {
error("%s: sshkey_to_base64 failed: %s", __func__, ssh_err(r));
goto out;
}
/* Turn the command into an argument vector */
if (split_argv(options.authorized_keys_command, &ac, &av) != 0) {
error("AuthorizedKeysCommand \"%s\" contains invalid quotes",
command);
goto out;
}
if (ac == 0) {
error("AuthorizedKeysCommand \"%s\" yielded no arguments",
command);
goto out;
}
for (i = 1; i < ac; i++) {
tmp = percent_expand(av[i],
"u", user_pw->pw_name,
"h", user_pw->pw_dir,
"t", sshkey_ssh_name(key),
"f", key_fp,
"k", keytext,
(char *)NULL);
if (tmp == NULL)
fatal("%s: percent_expand failed", __func__);
free(av[i]);
av[i] = tmp;
}
/* Prepare a printable command for logs, etc. */
command = assemble_argv(ac, av);
/*
* If AuthorizedKeysCommand was run without arguments
* then fall back to the old behaviour of passing the
* target username as a single argument.
*/
if (ac == 1) {
av = xreallocarray(av, ac + 2, sizeof(*av));
av[1] = xstrdup(user_pw->pw_name);
av[2] = NULL;
/* Fix up command too, since it is used in log messages */
free(command);
xasprintf(&command, "%s %s", av[0], av[1]);
}
if ((pid = subprocess("AuthorizedKeysCommand", pw, command,
ac, av, &f)) == 0)
goto out;
uid_swapped = 1;
temporarily_use_uid(pw);
ok = check_authkeys_file(f, options.authorized_keys_command, key, pw);
fclose(f);
f = NULL;
if (exited_cleanly(pid, "AuthorizedKeysCommand", command) != 0)
goto out;
/* Read completed successfully */
found_key = ok;
out:
if (f != NULL)
fclose(f);
signal(SIGCHLD, osigchld);
for (i = 0; i < ac; i++)
free(av[i]);
free(av);
if (uid_swapped)
restore_uid();
free(command);
free(username);
free(key_fp);
free(keytext);
return found_key;
}
/*
* Checks whether principal is allowed in output of command.
* returns 1 if the principal is allowed or 0 otherwise.
*/
static int
match_principals_command(struct passwd *user_pw, const struct sshkey *key)
{
const struct sshkey_cert *cert = key->cert;
FILE *f = NULL;
int r, ok, found_principal = 0;
struct passwd *pw;
int i, ac = 0, uid_swapped = 0;
pid_t pid;
char *tmp, *username = NULL, *command = NULL, **av = NULL;
char *ca_fp = NULL, *key_fp = NULL, *catext = NULL, *keytext = NULL;
char serial_s[16];
void (*osigchld)(int);
if (options.authorized_principals_command == NULL)
return 0;
if (options.authorized_principals_command_user == NULL) {
error("No user for AuthorizedPrincipalsCommand specified, "
"skipping");
return 0;
}
/*
* NB. all returns later this function should go via "out" to
* ensure the original SIGCHLD handler is restored properly.
*/
osigchld = signal(SIGCHLD, SIG_DFL);
/* Prepare and verify the user for the command */
username = percent_expand(options.authorized_principals_command_user,
"u", user_pw->pw_name, (char *)NULL);
pw = getpwnam(username);
if (pw == NULL) {
error("AuthorizedPrincipalsCommandUser \"%s\" not found: %s",
username, strerror(errno));
goto out;
}
/* Turn the command into an argument vector */
if (split_argv(options.authorized_principals_command, &ac, &av) != 0) {
error("AuthorizedPrincipalsCommand \"%s\" contains "
"invalid quotes", command);
goto out;
}
if (ac == 0) {
error("AuthorizedPrincipalsCommand \"%s\" yielded no arguments",
command);
goto out;
}
if ((ca_fp = sshkey_fingerprint(cert->signature_key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
error("%s: sshkey_fingerprint failed", __func__);
goto out;
}
if ((key_fp = sshkey_fingerprint(key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
error("%s: sshkey_fingerprint failed", __func__);
goto out;
}
if ((r = sshkey_to_base64(cert->signature_key, &catext)) != 0) {
error("%s: sshkey_to_base64 failed: %s", __func__, ssh_err(r));
goto out;
}
if ((r = sshkey_to_base64(key, &keytext)) != 0) {
error("%s: sshkey_to_base64 failed: %s", __func__, ssh_err(r));
goto out;
}
snprintf(serial_s, sizeof(serial_s), "%llu",
(unsigned long long)cert->serial);
for (i = 1; i < ac; i++) {
tmp = percent_expand(av[i],
"u", user_pw->pw_name,
"h", user_pw->pw_dir,
"t", sshkey_ssh_name(key),
"T", sshkey_ssh_name(cert->signature_key),
"f", key_fp,
"F", ca_fp,
"k", keytext,
"K", catext,
"i", cert->key_id,
"s", serial_s,
(char *)NULL);
if (tmp == NULL)
fatal("%s: percent_expand failed", __func__);
free(av[i]);
av[i] = tmp;
}
/* Prepare a printable command for logs, etc. */
command = assemble_argv(ac, av);
if ((pid = subprocess("AuthorizedPrincipalsCommand", pw, command,
ac, av, &f)) == 0)
goto out;
uid_swapped = 1;
temporarily_use_uid(pw);
ok = process_principals(f, NULL, pw, cert);
fclose(f);
f = NULL;
if (exited_cleanly(pid, "AuthorizedPrincipalsCommand", command) != 0)
goto out;
/* Read completed successfully */
found_principal = ok;
out:
if (f != NULL)
fclose(f);
signal(SIGCHLD, osigchld);
for (i = 0; i < ac; i++)
free(av[i]);
free(av);
if (uid_swapped)
restore_uid();
free(command);
free(username);
free(ca_fp);
free(key_fp);
free(catext);
free(keytext);
return found_principal;
}
/*
* Checks whether principal is allowed in output of command.
* returns 1 if the principal is allowed or 0 otherwise.
*/
static int
match_principals_command(struct passwd *user_pw, struct sshkey_cert *cert)
{
FILE *f = NULL;
int ok, found_principal = 0;
struct passwd *pw;
int i, ac = 0, uid_swapped = 0;
pid_t pid;
char *tmp, *username = NULL, *command = NULL, **av = NULL;
void (*osigchld)(int);
if (options.authorized_principals_command == NULL)
return 0;
if (options.authorized_principals_command_user == NULL) {
error("No user for AuthorizedPrincipalsCommand specified, "
"skipping");
return 0;
}
/*
* NB. all returns later this function should go via "out" to
* ensure the original SIGCHLD handler is restored properly.
*/
#ifndef WIN32_FIXME
// PRAGMA:TODO
osigchld = signal(SIGCHLD, SIG_DFL);
#endif
/* Prepare and verify the user for the command */
username = percent_expand(options.authorized_principals_command_user,
"u", user_pw->pw_name, (char *)NULL);
pw = getpwnam(username);
if (pw == NULL) {
error("AuthorizedPrincipalsCommandUser \"%s\" not found: %s",
username, strerror(errno));
goto out;
}
/* Turn the command into an argument vector */
if (split_argv(options.authorized_principals_command, &ac, &av) != 0) {
error("AuthorizedPrincipalsCommand \"%s\" contains "
"invalid quotes", command);
goto out;
}
if (ac == 0) {
error("AuthorizedPrincipalsCommand \"%s\" yielded no arguments",
command);
goto out;
}
for (i = 1; i < ac; i++) {
tmp = percent_expand(av[i],
"u", user_pw->pw_name,
"h", user_pw->pw_dir,
(char *)NULL);
if (tmp == NULL)
fatal("%s: percent_expand failed", __func__);
free(av[i]);
av[i] = tmp;
}
/* Prepare a printable command for logs, etc. */
command = assemble_argv(ac, av);
if ((pid = subprocess("AuthorizedPrincipalsCommand", pw, command,
ac, av, &f)) == 0)
goto out;
uid_swapped = 1;
temporarily_use_uid(pw);
ok = process_principals(f, NULL, pw, cert);
if (exited_cleanly(pid, "AuthorizedPrincipalsCommand", command) != 0)
goto out;
/* Read completed successfully */
found_principal = ok;
out:
if (f != NULL)
fclose(f);
signal(SIGCHLD, osigchld);
for (i = 0; i < ac; i++)
free(av[i]);
free(av);
if (uid_swapped)
restore_uid();
free(command);
free(username);
return found_principal;
}
