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/*
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* "ts3init_get_cookie and ts3init_get_puzzle" match extension for iptables
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* Niels Werensteijn <niels werensteijn [at] teamspeak com>, 2016-10-03
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License; either version 2
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* or 3 of the License, as published by the Free Software Foundation.
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*/
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <getopt.h>
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#include <xtables.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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#include "ts3init_random_seed.h"
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#include "ts3init_match.h"
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#define param_act(t, s, f) xtables_param_act((t), "ts3init_get_puzzle", (s), (f))
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
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static void ts3init_get_puzzle_help(void)
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{
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printf(
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"ts3init_get_puzzle match options:\n"
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" --min-client n The client needs to be at least version n.\n"
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" --check-cookie Check that the cookie was generated by same seed.\n"
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" --random-seed <seed> Seed is a %i byte hex number.\n"
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" A source could be /dev/random.\n"
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" --random-seed-file <file> Read the seed from a file.\n",
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RANDOM_SEED_LEN
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);
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}
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static const struct option ts3init_get_puzzle_opts[] = {
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{.name = "min-client", .has_arg = true, .val = '1'},
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{.name = "check-cookie", .has_arg = false, .val = '2'},
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{.name = "random-seed", .has_arg = true, .val = '3'},
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{.name = "random-seed-file", .has_arg = true, .val = '4'},
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{NULL},
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};
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static int ts3init_get_puzzle_parse(int c, char **argv, int invert, unsigned int *flags,
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const void *entry, struct xt_entry_match **match)
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{
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struct xt_ts3init_get_puzzle_mtinfo *info = (void *)(*match)->data;
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int client_version;
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switch (c) {
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case '1':
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param_act(XTF_ONLY_ONCE, "--min-client", info->common_options & CHK_COMMON_CLIENT_VERSION);
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param_act(XTF_NO_INVERT, "--min-client", invert);
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client_version = atoi(optarg);
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if (client_version <= 0)
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xtables_error(PARAMETER_PROBLEM,
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"ts3init_get_cookie: invalid min-client version");
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info->common_options |= CHK_COMMON_CLIENT_VERSION;
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info->min_client_version = client_version - CLIENT_VERSION_OFFSET;
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return true;
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case '2':
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param_act(XTF_ONLY_ONCE, "--check-cookie", info->specific_options & CHK_GET_PUZZLE_CHECK_COOKIE);
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param_act(XTF_NO_INVERT, "--check-cookie", invert);
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info->specific_options |= CHK_GET_PUZZLE_CHECK_COOKIE;
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*flags |= CHK_GET_PUZZLE_CHECK_COOKIE;
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return true;
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case '3':
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param_act(XTF_ONLY_ONCE, "--random-seed", info->specific_options & CHK_GET_PUZZLE_RANDOM_SEED_FROM_ARGUMENT);
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param_act(XTF_NO_INVERT, "--random-seed", invert);
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if (strlen(optarg) != (RANDOM_SEED_LEN * 2))
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xtables_error(PARAMETER_PROBLEM,
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"ts3init_get_puzzle: invalid random seed length");
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if (!parse_random_seed(optarg, info->random_seed))
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xtables_error(PARAMETER_PROBLEM,
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"ts3init_get_puzzle: invalid random seed. (not lowercase hex)");
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info->specific_options |= CHK_GET_PUZZLE_RANDOM_SEED_FROM_ARGUMENT;
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*flags |= CHK_GET_PUZZLE_RANDOM_SEED_FROM_ARGUMENT;
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return true;
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case '4':
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param_act(XTF_ONLY_ONCE, "--random-seed-file", info->specific_options & CHK_GET_PUZZLE_RANDOM_SEED_FROM_FILE);
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param_act(XTF_NO_INVERT, "--random-seed-file", invert);
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if (read_random_seed_from_file("ts3init_get_puzzle", optarg, info->random_seed))
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memcpy(info->random_seed_path, optarg, strlen(optarg) + 1);
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info->specific_options |= CHK_GET_PUZZLE_RANDOM_SEED_FROM_FILE;
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*flags |= CHK_GET_PUZZLE_RANDOM_SEED_FROM_FILE;
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return true;
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default:
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return false;
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}
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}
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static void ts3init_get_puzzle_save(const void *ip, const struct xt_entry_match *match)
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{
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int i;
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const struct xt_ts3init_get_puzzle_mtinfo *info = (const void *)match->data;
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if (info->common_options & CHK_COMMON_CLIENT_VERSION)
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{
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printf(" --min-client %u", info->min_client_version + CLIENT_VERSION_OFFSET);
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}
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if (info->specific_options & CHK_GET_PUZZLE_CHECK_COOKIE)
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{
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printf(" --check-cookie");
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}
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if (info->specific_options & CHK_GET_PUZZLE_RANDOM_SEED_FROM_ARGUMENT)
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{
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printf(" --random-seed ");
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for (i = 0; i < RANDOM_SEED_LEN; i++)
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{
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printf("%02X", info->random_seed[i]);
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}
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}
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if (info->specific_options & CHK_GET_PUZZLE_RANDOM_SEED_FROM_FILE)
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{
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printf(" --random-seed-file \"%s\"", info->random_seed_path);
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}
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}
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static void ts3init_get_puzzle_print(const void *ip, const struct xt_entry_match *match,
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int numeric)
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{
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printf(" -m ts3init_get_puzzle");
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ts3init_get_puzzle_save(ip, match);
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}
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static void ts3init_get_puzzle_check(unsigned int flags)
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{
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bool seed_from_argument = flags & CHK_GET_PUZZLE_RANDOM_SEED_FROM_ARGUMENT;
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bool seed_from_file = flags & CHK_GET_PUZZLE_RANDOM_SEED_FROM_FILE;
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if (seed_from_argument && seed_from_file)
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{
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xtables_error(PARAMETER_PROBLEM,
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"ts3init_get_puzzle: --random-seed and --random-seed-file "
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"can not be specified at the same time");
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}
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if (flags & CHK_GET_PUZZLE_CHECK_COOKIE)
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{
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if (!seed_from_argument && !seed_from_file)
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{
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xtables_error(PARAMETER_PROBLEM,
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"ts3init_get_puzzle: --check-cookie requires either "
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"--random-seed or --random-seed-file");
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}
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}
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}
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/* register and init */
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static struct xtables_match ts3init_mt_reg[] =
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{
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{
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.name = "ts3init_get_puzzle",
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.revision = 0,
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.family = NFPROTO_IPV4,
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.version = XTABLES_VERSION,
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.size = XT_ALIGN(sizeof(struct xt_ts3init_get_puzzle_mtinfo)),
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.userspacesize = XT_ALIGN(sizeof(struct xt_ts3init_get_puzzle_mtinfo)),
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.help = ts3init_get_puzzle_help,
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.parse = ts3init_get_puzzle_parse,
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.print = ts3init_get_puzzle_print,
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.save = ts3init_get_puzzle_save,
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.extra_opts = ts3init_get_puzzle_opts,
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.final_check = ts3init_get_puzzle_check,
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},
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{
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.name = "ts3init_get_puzzle",
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.revision = 0,
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.family = NFPROTO_IPV6,
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.version = XTABLES_VERSION,
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.size = XT_ALIGN(sizeof(struct xt_ts3init_get_puzzle_mtinfo)),
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.userspacesize = XT_ALIGN(sizeof(struct xt_ts3init_get_puzzle_mtinfo)),
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.help = ts3init_get_puzzle_help,
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.parse = ts3init_get_puzzle_parse,
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.print = ts3init_get_puzzle_print,
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.save = ts3init_get_puzzle_save,
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.extra_opts = ts3init_get_puzzle_opts,
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.final_check = ts3init_get_puzzle_check,
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}
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};
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static __attribute__((constructor)) void ts3init_mt_ldr(void)
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{
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xtables_register_matches(ts3init_mt_reg, ARRAY_SIZE(ts3init_mt_reg));
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}
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