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Tree: 1814bcb43cdf455b847c17f1313eb35d73f94716

Files: 1814bcb43cdf455b847c17f1313eb35d73f94716 / sslh-main.c

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1/*
2# main: processing of config file, command line options and start the main
3# loop.
4#
5# Copyright (C) 2007-2014  Yves Rutschle
6# 
7# This program is free software; you can redistribute it
8# and/or modify it under the terms of the GNU General Public
9# License as published by the Free Software Foundation; either
10# version 2 of the License, or (at your option) any later
11# version.
12# 
13# This program is distributed in the hope that it will be
14# useful, but WITHOUT ANY WARRANTY; without even the implied
15# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
16# PURPOSE.  See the GNU General Public License for more
17# details.
18# 
19# The full text for the General Public License is here:
20# http://www.gnu.org/licenses/gpl.html
21
22*/
23
24#define _GNU_SOURCE
25#ifdef LIBCONFIG
26#include <libconfig.h>
27#endif
28#ifdef ENABLE_REGEX
29#ifdef LIBPCRE
30#include <pcreposix.h>
31#else
32#include <regex.h>
33#endif
34#endif
35
36#include "common.h"
37#include "probe.h"
38
39const char* USAGE_STRING =
40"sslh " VERSION "\n" \
41"usage:\n" \
42"\tsslh  [-v] [-i] [-V] [-f] [-n] [--transparent] [-F <file>]\n"
43"\t[-t <timeout>] [-P <pidfile>] -u <username> -p <add> [-p <addr> ...] \n" \
44"%s\n\n" /* Dynamically built list of builtin protocols */  \
45"\t[--on-timeout <addr>]\n" \
46"-v: verbose\n" \
47"-V: version\n" \
48"-f: foreground\n" \
49"-n: numeric output\n" \
50"-u: specify under which user to run\n" \
51"--transparent: behave as a transparent proxy\n" \
52"-F: use configuration file\n" \
53"--on-timeout: connect to specified address upon timeout (default: ssh address)\n" \
54"-t: seconds to wait before connecting to --on-timeout address.\n" \
55"-p: address and port to listen on.\n    Can be used several times to bind to several addresses.\n" \
56"--[ssh,ssl,...]: where to connect connections from corresponding protocol.\n" \
57"-P: PID file.\n" \
58"-i: Run as a inetd service.\n" \
59"";
60
61/* Constants for options that have no one-character shorthand */
62#define OPT_ONTIMEOUT   257
63
64static struct option const_options[] = {
65    { "inetd",      no_argument,            &inetd,         1 },
66    { "foreground", no_argument,            &foreground,    1 },
67    { "background", no_argument,            &background,    1 },
68    { "transparent", no_argument,           &transparent,   1 },
69    { "numeric",    no_argument,            &numeric,       1 },
70    { "verbose",    no_argument,            &verbose,       1 },
71    { "user",       required_argument,      0,              'u' },
72    { "config",     optional_argument,      0,              'F' },
73    { "pidfile",    required_argument,      0,              'P' },
74    { "timeout",    required_argument,      0,              't' },
75    { "on-timeout", required_argument,      0,              OPT_ONTIMEOUT },
76    { "listen",     required_argument,      0,              'p' },
77    {}
78};
79static struct option* all_options;
80static struct proto* builtins;
81static const char *optstr = "vt:T:p:VP:F::";
82
83
84
85static void print_usage(void)
86{
87    struct proto *p;
88    int i;
89    int res;
90    char *prots = "";
91
92    p = get_builtins();
93    for (i = 0; i < get_num_builtins(); i++) {
94        res = asprintf(&prots, "%s\t[--%s <addr>]\n", prots, p[i].description);
95        CHECK_RES_DIE(res, "asprintf");
96    }
97
98    fprintf(stderr, USAGE_STRING, prots);
99}
100
101static void printcaps(void) {
102#ifdef LIBCAP
103    cap_t caps;
104    char* desc;
105    ssize_t len;
106
107    caps = cap_get_proc();
108
109    desc = cap_to_text(caps, &len);
110
111    fprintf(stderr, "capabilities: %s\n", desc);
112
113    cap_free(caps);
114    cap_free(desc);
115#endif
116}
117
118static void printsettings(void)
119{
120    char buf[NI_MAXHOST];
121    struct addrinfo *a;
122    struct proto *p;
123    
124    for (p = get_first_protocol(); p; p = p->next) {
125        fprintf(stderr,
126                "%s addr: %s. libwrap service: %s log_level: %d family %d %d\n", 
127                p->description, 
128                sprintaddr(buf, sizeof(buf), p->saddr), 
129                p->service,
130                p->log_level,
131                p->saddr->ai_family,
132                p->saddr->ai_addr->sa_family);
133    }
134    fprintf(stderr, "listening on:\n");
135    for (a = addr_listen; a; a = a->ai_next) {
136        fprintf(stderr, "\t%s\n", sprintaddr(buf, sizeof(buf), a));
137    }
138    fprintf(stderr, "timeout: %d\non-timeout: %s\n", probing_timeout,
139            timeout_protocol()->description);
140}
141
142
143/* Extract configuration on addresses and ports on which to listen.
144 * out: newly allocated list of addrinfo to listen to
145 */
146#ifdef LIBCONFIG
147static int config_listen(config_t *config, struct addrinfo **listen) 
148{
149    config_setting_t *setting, *addr;
150    int len, i;
151    const char *hostname, *port;
152
153    setting = config_lookup(config, "listen");
154    if (setting) {
155        len = config_setting_length(setting);
156        for (i = 0; i < len; i++) {
157            addr = config_setting_get_elem(setting, i);
158            if (! (config_setting_lookup_string(addr, "host", &hostname) &&
159                   config_setting_lookup_string(addr, "port", &port))) {
160                fprintf(stderr,
161                            "line %d:Incomplete specification (hostname and port required)\n",
162                            config_setting_source_line(addr));
163                return -1;
164            }
165
166            resolve_split_name(listen, hostname, port);
167
168            /* getaddrinfo returned a list of addresses corresponding to the
169             * specification; move the pointer to the end of that list before
170             * processing the next specification */
171            for (; *listen; listen = &((*listen)->ai_next));
172        }
173    }
174
175    return 0;
176}
177#endif
178
179
180
181#ifdef LIBCONFIG
182static void setup_regex_probe(struct proto *p, config_setting_t* probes)
183{
184#ifdef ENABLE_REGEX
185    int num_probes, errsize, i, res;
186    char *err;
187    const char * expr;
188    regex_t** probe_list;
189
190    num_probes = config_setting_length(probes);
191    if (!num_probes) {
192        fprintf(stderr, "%s: no probes specified\n", p->description);
193        exit(1);
194    }
195
196    p->probe = get_probe("regex");
197    probe_list = calloc(num_probes + 1, sizeof(*probe_list));
198    p->data = (void*)probe_list;
199
200    for (i = 0; i < num_probes; i++) {
201        probe_list[i] = malloc(sizeof(*(probe_list[i])));
202        expr = config_setting_get_string_elem(probes, i);
203        res = regcomp(probe_list[i], expr, 0);
204        if (res) {
205            err = malloc(errsize = regerror(res, probe_list[i], NULL, 0));
206            regerror(res, probe_list[i], err, errsize);
207            fprintf(stderr, "%s:%s\n", expr, err);
208            free(err);
209            exit(1);
210        }
211    }
212#else
213    fprintf(stderr, "line %d: regex probe specified but not compiled in\n", config_setting_source_line(probes));
214    exit(5);
215#endif
216}
217#endif
218
219#ifdef LIBCONFIG
220static void setup_sni_alpn_list(struct proto *p, config_setting_t* config_items, const char* name, int alpn)
221{
222    int num_probes, i, max_server_name_len, server_name_len;
223    const char * config_item;
224    char** sni_hostname_list;
225
226    if(!config_items || !config_setting_is_array(config_items)) {
227        fprintf(stderr, "%s: no %s specified\n", p->description, name);
228        return;
229    }
230    num_probes = config_setting_length(config_items);
231    if (!num_probes) {
232        fprintf(stderr, "%s: no %s specified\n", p->description, name);
233        return;
234    }
235
236    max_server_name_len = 0;
237    for (i = 0; i < num_probes; i++) {
238        server_name_len = strlen(config_setting_get_string_elem(config_items, i));
239        if(server_name_len > max_server_name_len)
240            max_server_name_len = server_name_len;
241    }
242
243    sni_hostname_list = calloc(num_probes + 1, ++max_server_name_len);
244
245    for (i = 0; i < num_probes; i++) {
246        config_item = config_setting_get_string_elem(config_items, i);
247        sni_hostname_list[i] = malloc(max_server_name_len);
248        strcpy (sni_hostname_list[i], config_item);
249        if(verbose) fprintf(stderr, "%s: %s[%d]: %s\n", p->description, name, i, sni_hostname_list[i]);
250    }
251
252    p->data = (void*)tls_data_set_list(p->data, alpn, sni_hostname_list);
253}
254
255static void setup_sni_alpn(struct proto *p, config_setting_t* sni_hostnames, config_setting_t* alpn_protocols)
256{
257    p->data = (void*)new_tls_data();
258    p->probe = get_probe("sni_alpn");
259    setup_sni_alpn_list(p, sni_hostnames, "sni_hostnames", 0);
260    setup_sni_alpn_list(p, alpn_protocols, "alpn_protocols", 1);
261}
262#endif
263
264/* Extract configuration for protocols to connect to.
265 * out: newly-allocated list of protocols
266 */
267#ifdef LIBCONFIG
268static int config_protocols(config_t *config, struct proto **prots)
269{
270    config_setting_t *setting, *prot, *patterns, *sni_hostnames, *alpn_protocols;
271    const char *hostname, *port, *name;
272    int i, num_prots;
273    struct proto *p, *prev = NULL;
274
275    setting = config_lookup(config, "protocols");
276    if (setting) {
277        num_prots = config_setting_length(setting);
278        for (i = 0; i < num_prots; i++) {
279            p = calloc(1, sizeof(*p));
280            if (i == 0) *prots = p;
281            if (prev) prev->next = p;
282            prev = p;
283
284            prot = config_setting_get_elem(setting, i);
285            if ((config_setting_lookup_string(prot, "name", &name) &&
286                 config_setting_lookup_string(prot, "host", &hostname) &&
287                 config_setting_lookup_string(prot, "port", &port)
288                )) {
289                p->description = name;
290                config_setting_lookup_string(prot, "service", &(p->service));
291
292                if (config_setting_lookup_int(prot, "log_level", &p->log_level) == CONFIG_FALSE) {
293                    p->log_level = 1;
294                }
295
296                resolve_split_name(&(p->saddr), hostname, port);
297
298                p->probe = get_probe(name);
299                if (!p->probe || !strcmp(name, "sni_alpn")) {
300                    fprintf(stderr, "line %d: %s: probe unknown\n", config_setting_source_line(prot), name);
301                    exit(1);
302                }
303
304                /* Probe-specific options: regex patterns */
305                if (!strcmp(name, "regex")) {
306                    patterns = config_setting_get_member(prot, "regex_patterns");
307                    if (patterns && config_setting_is_array(patterns)) {
308                        setup_regex_probe(p, patterns);
309                    }
310                }
311
312                /* Probe-specific options: SNI/ALPN */
313                if (!strcmp(name, "tls")) {
314                    sni_hostnames = config_setting_get_member(prot, "sni_hostnames");
315                    alpn_protocols = config_setting_get_member(prot, "alpn_protocols");
316
317                    if((sni_hostnames && config_setting_is_array(sni_hostnames)) || (alpn_protocols && config_setting_is_array(alpn_protocols))) {
318                        setup_sni_alpn(p, sni_hostnames, alpn_protocols);
319                    }
320                }
321
322            }
323        }
324    }
325
326    return 0;
327}
328#endif
329
330/* Parses a config file
331 * in: *filename
332 * out: *listen, a newly-allocated linked list of listen addrinfo
333 *      *prots, a newly-allocated linked list of protocols
334 *      1 on error, 0 on success
335 */
336#ifdef LIBCONFIG
337static int config_parse(char *filename, struct addrinfo **listen, struct proto **prots)
338{
339    config_t config;
340    int timeout;
341    const char* str;
342
343    config_init(&config);
344    if (config_read_file(&config, filename) == CONFIG_FALSE) {
345        /* If it's a parse error then there will be a line number for the failure
346         * an I/O error (such as non-existent file) will have the error line as 0
347         */
348        if (config_error_line(&config) != 0) {
349            fprintf(stderr, "%s:%d:%s\n", 
350                    filename,
351                    config_error_line(&config),
352                    config_error_text(&config));
353            exit(1);
354        }
355        fprintf(stderr, "%s:%s\n", 
356                filename,
357                config_error_text(&config));
358        return 1;
359    }
360
361    config_lookup_bool(&config, "verbose", &verbose);
362    config_lookup_bool(&config, "inetd", &inetd);
363    config_lookup_bool(&config, "foreground", &foreground);
364    config_lookup_bool(&config, "numeric", &numeric);
365    config_lookup_bool(&config, "transparent", &transparent);
366
367    if (config_lookup_int(&config, "timeout", (int *)&timeout) == CONFIG_TRUE) {
368        probing_timeout = timeout;
369    }
370
371    if (config_lookup_string(&config, "on-timeout", &str)) {
372        set_ontimeout(str);
373    }
374
375    config_lookup_string(&config, "user", &user_name);
376    config_lookup_string(&config, "pidfile", &pid_file);
377
378    config_listen(&config, listen);
379    config_protocols(&config, prots);
380
381    return 0;
382}
383#endif
384
385/* Adds protocols to the list of options, so command-line parsing uses the
386 * protocol definition array 
387 * options: array of options to add to; must be big enough
388 * n_opts: number of options in *options before calling (i.e. where to append)
389 * prot: array of protocols
390 * n_prots: number of protocols in *prot
391 * */
392static void append_protocols(struct option *options, int n_opts, struct proto *prot , int n_prots)
393{
394    int o, p;
395
396    for (o = n_opts, p = 0; p < n_prots; o++, p++) {
397        options[o].name = prot[p].description;
398        options[o].has_arg = required_argument;
399        options[o].flag = 0;
400        options[o].val = p + PROT_SHIFT;
401    }
402}
403
404static void make_alloptions(void)
405{
406    builtins = get_builtins();
407
408    /* Create all_options, composed of const_options followed by one option per
409     * known protocol */
410    all_options = calloc(ARRAY_SIZE(const_options) + get_num_builtins(), sizeof(struct option));
411    memcpy(all_options, const_options, sizeof(const_options));
412    append_protocols(all_options, ARRAY_SIZE(const_options) - 1, builtins, get_num_builtins());
413}
414
415/* Performs a first scan of command line options to see if a configuration file
416 * is specified. If there is one, parse it now before all other options (so
417 * configuration file settings can be overridden from the command line).
418 *
419 * prots: newly-allocated list of configured protocols, if any.
420 */
421static void cmdline_config(int argc, char* argv[], struct proto** prots)
422{
423#ifdef LIBCONFIG
424    int c, res;
425    char *config_filename;
426#endif
427
428    make_alloptions();
429
430#ifdef LIBCONFIG
431    optind = 1;
432    opterr = 0; /* we're missing protocol options at this stage so don't output errors */
433    while ((c = getopt_long_only(argc, argv, optstr, all_options, NULL)) != -1) {
434        if (c == 'v') {
435            verbose++;
436        }
437        if (c == 'F') {
438            config_filename = optarg;
439            if (config_filename) {
440                res = config_parse(config_filename, &addr_listen, prots);
441            } else {
442                /* No configuration file specified -- try default file locations */
443                res = config_parse("/etc/sslh/sslh.cfg", &addr_listen, prots);
444                if (!res && verbose) fprintf(stderr, "Using /etc/sslh/sslh.cfg\n");
445                if (res) {
446                    res = config_parse("/etc/sslh.cfg", &addr_listen, prots);
447                    if (!res && verbose) fprintf(stderr, "Using /etc/sslh.cfg\n");
448                }
449            }
450            if (res)
451                exit(4);
452            break;
453        }
454    }
455#endif
456}
457
458
459/* Parse command-line options. prots points to a list of configured protocols,
460 * potentially non-allocated */
461static void parse_cmdline(int argc, char* argv[], struct proto* prots)
462{
463    int c;
464    struct addrinfo **a;
465    struct proto *p;
466
467    optind = 1;
468    opterr = 1;
469next_arg:
470    while ((c = getopt_long_only(argc, argv, optstr, all_options, NULL)) != -1) {
471        if (c == 0) continue;
472
473        if (c >= PROT_SHIFT) {
474            if (prots)
475                for (p = prots; p && p->next; p = p->next) {
476                    /* override if protocol was already defined by config file 
477                     * (note it only overrides address and use builtin probe) */
478                    if (!strcmp(p->description, builtins[c-PROT_SHIFT].description)) {
479                        resolve_name(&(p->saddr), optarg);
480                        p->probe = builtins[c-PROT_SHIFT].probe;
481                        goto next_arg;
482                    }
483                }
484            /* At this stage, it's a new protocol: add it to the end of the
485             * list */
486            if (!prots) {
487                /* No protocols yet -- create the list */
488                p = prots = calloc(1, sizeof(*p));
489            } else {
490                p->next = calloc(1, sizeof(*p));
491                p = p->next;
492            }
493            memcpy(p, &builtins[c-PROT_SHIFT], sizeof(*p));
494            resolve_name(&(p->saddr), optarg);
495            continue;
496        }
497
498        switch (c) {
499
500        case 'F':
501            /* Legal option, but do nothing, it was already processed in
502             * cmdline_config() */
503#ifndef LIBCONFIG
504            fprintf(stderr, "Built without libconfig support: configuration file not available.\n");
505            exit(1);
506#endif
507            break;
508
509        case 't':
510             probing_timeout = atoi(optarg);
511            break;
512
513        case OPT_ONTIMEOUT:
514            set_ontimeout(optarg);
515            break;
516
517        case 'p':
518            /* find the end of the listen list */
519            for (a = &addr_listen; *a; a = &((*a)->ai_next));
520            /* append the specified addresses */
521            resolve_name(a, optarg);
522            
523            break;
524
525        case 'V':
526            printf("%s %s\n", server_type, VERSION);
527            exit(0);
528
529        case 'u':
530            user_name = optarg;
531            break;
532
533        case 'P':
534            pid_file = optarg;
535            break;
536
537        case 'v':
538            verbose++;
539            break;
540
541        default:
542            print_usage();
543            exit(2);
544        }
545    }
546
547    if (!prots) {
548        fprintf(stderr, "At least one target protocol must be specified.\n");
549        exit(2);
550    }
551
552    set_protocol_list(prots);
553
554    if (!addr_listen && !inetd) {
555        fprintf(stderr, "No listening address specified; use at least one -p option\n");
556        exit(1);
557    }
558
559    /* Did command-line override foreground setting? */
560    if (background)
561        foreground = 0;
562
563}
564
565int main(int argc, char *argv[])
566{
567
568   extern char *optarg;
569   extern int optind;
570   int res, num_addr_listen;
571   struct proto* protocols = NULL;
572
573   int *listen_sockets;
574
575   /* Init defaults */
576   pid_file = NULL;
577   user_name = NULL;
578
579   cmdline_config(argc, argv, &protocols);
580   parse_cmdline(argc, argv, protocols);
581
582   if (inetd)
583   {
584       verbose = 0;
585       start_shoveler(0);
586       exit(0);
587   }
588
589   if (verbose)
590       printsettings();
591
592   num_addr_listen = start_listen_sockets(&listen_sockets, addr_listen);
593
594   if (!foreground) {
595       if (fork() > 0) exit(0); /* Detach */
596
597       /* New session -- become group leader */
598       if (getuid() == 0) {
599           res = setsid();
600           CHECK_RES_DIE(res, "setsid: already process leader");
601       }
602   }
603
604   setup_signals();
605
606   if (pid_file)
607       write_pid_file(pid_file);
608
609   if (user_name)
610       drop_privileges(user_name);
611
612
613   /* Open syslog connection */
614   setup_syslog(argv[0]);
615
616   if (verbose)
617       printcaps();
618
619   main_loop(listen_sockets, num_addr_listen);
620
621   return 0;
622}
623

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