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/*
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* "ts3init_set_cookie" target 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_target.h"
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#define param_act(t, s, f) xtables_param_act((t), "TS3INIT_SET_COOKIE", (s), (f))
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static void ts3init_set_cookie_tg_help(void)
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{
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printf(
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"TS3INIT_SET_COOKIE target options:\n"
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" --zero-random-sequence Always return 0 as random sequence.\n"
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" --random-seed <seed> Seed is a %i byte hex number in.\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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static const struct option ts3init_set_cookie_tg_opts[] = {
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{.name = "zero-random-sequence", .has_arg = false, .val = '1'},
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{.name = "random-seed", .has_arg = true, .val = '2'},
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{.name = "random-seed-file", .has_arg = true, .val = '3'},
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{NULL},
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};
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static int ts3init_set_cookie_tg_parse(int c, char **argv,
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int invert, unsigned int *flags, const void *entry,
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struct xt_entry_target **target)
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{
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struct xt_ts3init_set_cookie_tginfo *info = (void *)(*target)->data;
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switch (c) {
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case '1':
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param_act(XTF_ONLY_ONCE, "--zero-random-sequence", info->specific_options & TARGET_SET_COOKIE_ZERO_RANDOM_SEQUENCE);
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param_act(XTF_NO_INVERT, "--zero-random-sequence", invert);
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info->specific_options |= TARGET_SET_COOKIE_ZERO_RANDOM_SEQUENCE;
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return true;
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case '2':
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param_act(XTF_ONLY_ONCE, "--random-seed", *flags & TARGET_SET_COOKIE_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_SET_COOKIE: 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_SET_COOKIE: invalid random seed. (not lowercase hex)");
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info->specific_options |= TARGET_SET_COOKIE_RANDOM_SEED_FROM_ARGUMENT;
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*flags |= TARGET_SET_COOKIE_RANDOM_SEED_FROM_ARGUMENT;
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return true;
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case '3':
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param_act(XTF_ONLY_ONCE, "--random-seed-file", *flags & TARGET_SET_COOKIE_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_SET_COOKIE", optarg, info->random_seed))
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memcpy(info->random_seed_path, optarg, strlen(optarg) + 1);
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info->specific_options |= TARGET_SET_COOKIE_RANDOM_SEED_FROM_FILE;
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*flags |= TARGET_SET_COOKIE_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_set_cookie_tg_save(const void *ip, const struct xt_entry_target *target)
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{
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int i;
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const struct xt_ts3init_set_cookie_tginfo *info = (const void *)target->data;
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if (info->specific_options & TARGET_SET_COOKIE_ZERO_RANDOM_SEQUENCE)
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{
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printf(" --zero-random-sequence");
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}
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if (info->specific_options & TARGET_SET_COOKIE_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 & TARGET_SET_COOKIE_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_set_cookie_tg_print(const void *ip, const struct xt_entry_target *target,
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int numeric)
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{
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printf(" -j TS3INIT_SET_COOKIE");
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ts3init_set_cookie_tg_save(ip, target);
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}
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static void ts3init_set_cookie_tg_check(unsigned int flags)
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{
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bool random_seed_from_argument = flags & TARGET_SET_COOKIE_RANDOM_SEED_FROM_ARGUMENT;
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bool random_seed_from_file = flags & TARGET_SET_COOKIE_RANDOM_SEED_FROM_FILE;
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if (random_seed_from_argument && random_seed_from_file)
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{
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xtables_error(PARAMETER_PROBLEM,
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"TS3INIT_SET_COOKIE: --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 (!random_seed_from_argument && !random_seed_from_file)
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{
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xtables_error(PARAMETER_PROBLEM,
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"TS3INIT_SET_COOKIE: either --random-seed or --random-seed-file "
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"must be specified");
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}
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}
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/* register and init */
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static struct xtables_target ts3init_set_cookie_tg_reg =
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{
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.name = "TS3INIT_SET_COOKIE",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.version = XTABLES_VERSION,
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.size = XT_ALIGN(sizeof(struct xt_ts3init_set_cookie_tginfo)),
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.userspacesize = XT_ALIGN(sizeof(struct xt_ts3init_set_cookie_tginfo)),
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.help = ts3init_set_cookie_tg_help,
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.parse = ts3init_set_cookie_tg_parse,
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.print = ts3init_set_cookie_tg_print,
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.save = ts3init_set_cookie_tg_save,
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.final_check = ts3init_set_cookie_tg_check,
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.extra_opts = ts3init_set_cookie_tg_opts,
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};
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static __attribute__((constructor)) void ts3init_set_cookie_tg_ldr(void)
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{
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xtables_register_target(&ts3init_set_cookie_tg_reg);
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}
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