moparisthebest
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sslh
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sslh/sslh-main.c

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/*
# main: processing of config file, command line options and start the main loop.
#
# Copyright (C) 2007-2012 Yves Rutschle
#
# This program is free software; you can redistribute it
# and/or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
# PURPOSE. See the GNU General Public License for more
# details.
#
# The full text for the General Public License is here:
# http://www.gnu.org/licenses/gpl.html
*/
#define _GNU_SOURCE
#ifdef LIBCONFIG
#include <libconfig.h>
#endif
#include <regex.h>
#include "common.h"
#include "probe.h"
const char* USAGE_STRING =
"sslh " VERSION "\n" \
"usage:\n" \
"\tsslh [-v] [-i] [-V] [-f] [-n] [-F <file>]\n"
"\t[-t <timeout>] [-P <pidfile>] -u <username> -p <add> [-p <addr> ...] \n" \
"%s\n\n" /* Dynamically built list of builtin protocols */ \
"-v: verbose\n" \
"-V: version\n" \
"-f: foreground\n" \
"-n: numeric output\n" \
"-F: use configuration file\n" \
"-t: timeout before connecting to SSH.\n" \
"-p: address and port to listen on.\n Can be used several times to bind to several addresses.\n" \
"--[ssh,ssl,...]: where to connect connections from corresponding protocol.\n" \
"-F: specify a configuration file\n" \
"-P: PID file.\n" \
"-i: Run as a inetd service.\n" \
"";
static struct option const_options[] = {
{ "inetd", no_argument, &inetd, 1 },
{ "foreground", no_argument, &foreground, 1 },
{ "numeric", no_argument, &numeric, 1 },
{ "verbose", no_argument, &verbose, 1 },
{ "user", required_argument, 0, 'u' },
{ "config", required_argument, 0, 'F' },
{ "pidfile", required_argument, 0, 'P' },
{ "timeout", required_argument, 0, 't' },
{ "listen", required_argument, 0, 'p' },
{}
};
static struct option* all_options;
static struct proto* builtins;
static const char *optstr = "vt:T:p:VP:F:";
static void print_usage(void)
{
struct proto *p;
char *prots = "";
for (p = get_first_protocol(); p; p = p->next)
asprintf(&prots, "%s\t[--%s <addr>]\n", prots, p->description);
fprintf(stderr, USAGE_STRING, prots);
}
static void printsettings(void)
{
char buf[NI_MAXHOST];
struct addrinfo *a;
struct proto *p;
for (p = get_first_protocol(); p; p = p->next) {
fprintf(stderr,
"%s addr: %s. libwrap service: %s family %d %d\n",
p->description,
sprintaddr(buf, sizeof(buf), p->saddr),
p->service,
p->saddr->ai_family,
p->saddr->ai_addr->sa_family);
}
fprintf(stderr, "listening on:\n");
for (a = addr_listen; a; a = a->ai_next) {
fprintf(stderr, "\t%s\n", sprintaddr(buf, sizeof(buf), a));
}
fprintf(stderr, "timeout to ssh: %d\n", probing_timeout);
}
/* Extract configuration on addresses and ports on which to listen.
* out: newly allocated list of addrinfo to listen to
*/
#ifdef LIBCONFIG
static int config_listen(config_t *config, struct addrinfo **listen)
{
config_setting_t *setting, *addr;
int len, i;
const char *hostname, *port;
setting = config_lookup(config, "listen");
if (setting) {
len = config_setting_length(setting);
for (i = 0; i < len; i++) {
addr = config_setting_get_elem(setting, i);
if (! (config_setting_lookup_string(addr, "host", &hostname) &&
config_setting_lookup_string(addr, "port", &port))) {
fprintf(stderr,
"line %d:Incomplete specification (hostname and port required)\n",
config_setting_source_line(addr));
return -1;
}
resolve_split_name(listen, hostname, port);
/* getaddrinfo returned a list of addresses corresponding to the
* specification; move the pointer to the end of that list before
* processing the next specification */
for (; *listen; listen = &((*listen)->ai_next));
}
}
return 0;
}
#endif
#ifdef LIBCONFIG
static void setup_regex_probe(struct proto *p, config_setting_t* probes)
{
int num_probes, errsize, i, res;
char *err;
const char * expr;
regex_t** probe_list;
num_probes = config_setting_length(probes);
if (!num_probes) {
fprintf(stderr, "%s: no probes specified\n", p->description);
exit(1);
}
p->probe = get_probe("regex");
probe_list = calloc(num_probes + 1, sizeof(*probe_list));
p->data = (void*)probe_list;
for (i = 0; i < num_probes; i++) {
probe_list[i] = malloc(sizeof(*(probe_list[i])));
expr = config_setting_get_string_elem(probes, i);
res = regcomp(probe_list[i], expr, 0);
if (res) {
err = malloc(errsize = regerror(res, probe_list[i], NULL, 0));
regerror(res, probe_list[i], err, errsize);
fprintf(stderr, "%s:%s\n", expr, err);
free(err);
exit(1);
}
}
}
#endif
/* Extract configuration for protocols to connect to.
* out: newly-allocated list of protocols
*/
#ifdef LIBCONFIG
static int config_protocols(config_t *config, struct proto **prots)
{
config_setting_t *setting, *prot, *probes;
const char *hostname, *port, *name;
int i, num_prots;
struct proto *p, *prev = NULL;
setting = config_lookup(config, "protocols");
if (setting) {
num_prots = config_setting_length(setting);
for (i = 0; i < num_prots; i++) {
p = calloc(1, sizeof(*p));
if (i == 0) *prots = p;
if (prev) prev->next = p;
prev = p;
prot = config_setting_get_elem(setting, i);
if ((config_setting_lookup_string(prot, "name", &name) &&
config_setting_lookup_string(prot, "host", &hostname) &&
config_setting_lookup_string(prot, "port", &port)
)) {
p->description = name;
config_setting_lookup_string(prot, "service", &(p->service));
resolve_split_name(&(p->saddr), hostname, port);
probes = config_setting_get_member(prot, "probe");
if (config_setting_is_array(probes)) {
/* If 'probe' is an array, setup a regex probe using the
* array of strings as pattern */
setup_regex_probe(p, probes);
} else {
/* if 'probe' is 'builtin', set the probe to the
* appropriate builtin protocol */
if (!strcmp(config_setting_get_string(probes), "builtin")) {
p->probe = get_probe(name);
if (!p->probe) {
fprintf(stderr, "%s: no builtin probe for this protocol\n", name);
exit(1);
}
} else {
fprintf(stderr, "%s: illegal probe name\n", name);
exit(1);
}
}
}
}
}
return 0;
}
#endif
/* Parses a config file
* in: *filename
* out: *listen, a newly-allocated linked list of listen addrinfo
* *prots, a newly-allocated linked list of protocols
*/
#ifdef LIBCONFIG
static int config_parse(char *filename, struct addrinfo **listen, struct proto **prots)
{
config_t config;
long int timeout;
config_init(&config);
if (config_read_file(&config, filename) == CONFIG_FALSE) {
fprintf(stderr, "%s:%d:%s\n",
filename,
config_error_line(&config),
config_error_text(&config));
exit(1);
}
config_lookup_bool(&config, "verbose", &verbose);
config_lookup_bool(&config, "inetd", &inetd);
config_lookup_bool(&config, "foreground", &foreground);
config_lookup_bool(&config, "numeric", &numeric);
if (config_lookup_int(&config, "timeout", &timeout) == CONFIG_TRUE) {
probing_timeout = timeout;
}
config_lookup_string(&config, "user", &user_name);
config_lookup_string(&config, "pidfile", &pid_file);
config_listen(&config, listen);
config_protocols(&config, prots);
return 0;
}
#endif
/* Adds protocols to the list of options, so command-line parsing uses the
* protocol definition array
* options: array of options to add to; must be big enough
* n_opts: number of options in *options before calling (i.e. where to append)
* prot: array of protocols
* n_prots: number of protocols in *prot
* */
static void append_protocols(struct option *options, int n_opts, struct proto *prot , int n_prots)
{
int o, p;
for (o = n_opts, p = 0; p < n_prots; o++, p++) {
options[o].name = prot[p].description;
options[o].has_arg = required_argument;
options[o].flag = 0;
options[o].val = p + PROT_SHIFT;
}
}
static void make_alloptions(void)
{
builtins = get_builtins();
/* Create all_options, composed of const_options followed by one option per
* known protocol */
all_options = calloc(ARRAY_SIZE(const_options) + get_num_builtins(), sizeof(struct option));
memcpy(all_options, const_options, sizeof(const_options));
append_protocols(all_options, ARRAY_SIZE(const_options) - 1, builtins, get_num_builtins());
}
/* Performs a first scan of command line options to see if a configuration file
* is specified. If there is one, parse it now before all other options (so
* configuration file settings can be overridden from the command line).
*
* prots: newly-allocated list of configured protocols, if any.
*/
static void cmdline_config(int argc, char* argv[], struct proto** prots)
{
#ifdef LIBCONFIG
int c, res;
char *config_filename;
#endif
make_alloptions();
#ifdef LIBCONFIG
optind = 1;
opterr = 0; /* we're missing protocol options at this stage so don't output errors */
while ((c = getopt_long_only(argc, argv, optstr, all_options, NULL)) != -1) {
if (c == 'F') {
config_filename = optarg;
/* find the end of the listen list */
res = config_parse(config_filename, &addr_listen, prots);
if (res)
exit(4);
break;
}
}
#endif
}
/* Parse command-line options. prots points to a list of configured protocols,
* potentially non-allocated */
static void parse_cmdline(int argc, char* argv[], struct proto* prots)
{
int c;
struct addrinfo **a;
struct proto *p;
optind = 1;
opterr = 1;
next_arg:
while ((c = getopt_long_only(argc, argv, optstr, all_options, NULL)) != -1) {
if (c == 0) continue;
if (c >= PROT_SHIFT) {
if (prots)
for (p = prots; p && p->next; p = p->next) {
/* override if protocol was already defined by config file
* (note it only overrides address and use builtin probe) */
if (!strcmp(p->description, builtins[c-PROT_SHIFT].description)) {
resolve_name(&(p->saddr), optarg);
p->probe = builtins[c-PROT_SHIFT].probe;
goto next_arg;
}
}
/* At this stage, it's a new protocol: add it to the end of the
* list */
if (!prots) {
/* No protocols yet -- create the list */
p = prots = calloc(1, sizeof(*p));
} else {
p->next = calloc(1, sizeof(*p));
p = p->next;
}
memcpy(p, &builtins[c-PROT_SHIFT], sizeof(*p));
resolve_name(&(p->saddr), optarg);
continue;
}
switch (c) {
case 'F':
/* Legal option, but do nothing, it was already processed in
* cmdline_config() */
#ifndef LIBCONFIG
fprintf(stderr, "Built without libconfig support: configuration file not available.\n");
exit(1);
#endif
break;
case 't':
probing_timeout = atoi(optarg);
break;
case 'p':
/* find the end of the listen list */
for (a = &addr_listen; *a; a = &((*a)->ai_next));
/* append the specified addresses */
resolve_name(a, optarg);
break;
case 'V':
printf("%s %s\n", server_type, VERSION);
exit(0);
case 'u':
user_name = optarg;
break;
case 'P':
pid_file = optarg;
break;
case 'v':
verbose++;
break;
default:
print_usage();
exit(2);
}
}
if (!prots) {
fprintf(stderr, "At least one target protocol must be specified.\n");
exit(2);
}
set_protocol_list(prots);
if (!addr_listen) {
fprintf(stderr, "No listening address specified; use at least one -p option\n");
exit(1);
}
}
int main(int argc, char *argv[])
{
extern char *optarg;
extern int optind;
int res, num_addr_listen;
struct proto* protocols = NULL;
int *listen_sockets;
/* Init defaults */
pid_file = NULL;
user_name = NULL;
cmdline_config(argc, argv, &protocols);
parse_cmdline(argc, argv, protocols);
if (inetd)
{
verbose = 0;
start_shoveler(0);
exit(0);
}
if (verbose)
printsettings();
num_addr_listen = start_listen_sockets(&listen_sockets, addr_listen);
if (!foreground) {
if (fork() > 0) exit(0); /* Detach */
/* New session -- become group leader */
if (getuid() == 0) {
res = setsid();
CHECK_RES_DIE(res, "setsid: already process leader");
}
}
setup_signals();
if (user_name)
drop_privileges(user_name);
if (pid_file)
write_pid_file(pid_file);
/* Open syslog connection */
setup_syslog(argv[0]);
main_loop(listen_sockets, num_addr_listen);
return 0;
}
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