Module Name: src Committed By: christos Date: Sun Mar 7 14:59:36 UTC 2021
Modified Files: src/sys/netinet6: ip6_id.c Log Message: netinet6: Mark randomid unused. Will make merging and bisection easier if anything goes wrong with flow label or fragment id randomization changes. (from riastradh) To generate a diff of this commit: cvs rdiff -u -r1.19 -r1.20 src/sys/netinet6/ip6_id.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/netinet6/ip6_id.c diff -u src/sys/netinet6/ip6_id.c:1.19 src/sys/netinet6/ip6_id.c:1.20 --- src/sys/netinet6/ip6_id.c:1.19 Fri Oct 18 00:09:02 2019 +++ src/sys/netinet6/ip6_id.c Sun Mar 7 09:59:36 2021 @@ -1,9 +1,7 @@ -/* $NetBSD: ip6_id.c,v 1.19 2019/10/18 04:09:02 msaitoh Exp $ */ -/* $KAME: ip6_id.c,v 1.8 2003/09/06 13:41:06 itojun Exp $ */ -/* $OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $ */ +/* $NetBSD: ip6_id.c,v 1.20 2021/03/07 14:59:36 christos Exp $ */ -/* - * Copyright (C) 2003 WIDE Project. +/*- + * Copyright (c) 2020 The NetBSD Foundation, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -14,241 +12,38 @@ * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. - * 3. Neither the name of the project nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. * - * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - */ - -/* - * Copyright 1998 Niels Provos <pro...@citi.umich.edu> - * All rights reserved. - * - * Theo de Raadt <dera...@openbsd.org> came up with the idea of using - * such a mathematical system to generate more random (yet non-repeating) - * ids to solve the resolver/named problem. But Niels designed the - * actual system based on the constraints. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. - * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF - * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -/* - * seed = random (bits - 1) bit - * n = prime, g0 = generator to n, - * j = random so that gcd(j,n-1) == 1 - * g = g0^j mod n will be a generator again. - * - * X[0] = random seed. - * X[n] = a*X[n-1]+b mod m is a Linear Congruential Generator - * with a = 7^(even random) mod m, - * b = random with gcd(b,m) == 1 - * m = constant and a maximal period of m-1. - * - * The transaction id is determined by: - * id[n] = seed xor (g^X[n] mod n) - * - * Effectively the id is restricted to the lower (bits - 1) bits, thus - * yielding two different cycles by toggling the msb on and off. - * This avoids reuse issues caused by reseeding. + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: ip6_id.c,v 1.19 2019/10/18 04:09:02 msaitoh Exp $"); +__KERNEL_RCSID(0, "$NetBSD: ip6_id.c,v 1.20 2021/03/07 14:59:36 christos Exp $"); -#include <sys/param.h> +#include <sys/types.h> #include <sys/cprng.h> -#include <lib/libkern/libkern.h> - -#include <net/if.h> -#include <netinet/in.h> -#include <netinet/ip6.h> #include <netinet6/ip6_var.h> -struct randomtab { - const int ru_bits; /* resulting bits */ - const long ru_out; /* Time after wich will be reseeded */ - const u_int32_t ru_max; /* Uniq cycle, avoid blackjack prediction */ - const u_int32_t ru_gen; /* Starting generator */ - const u_int32_t ru_n; /* ru_n: prime, ru_n - 1: product of pfacts[] */ - const u_int32_t ru_agen; /* determine ru_a as ru_agen^(2*rand) */ - const u_int32_t ru_m; /* ru_m = 2^x*3^y */ - const u_int32_t ru_pfacts[4]; /* factors of ru_n */ - - u_int32_t ru_counter; - u_int32_t ru_msb; - - u_int32_t ru_x; - u_int32_t ru_seed, ru_seed2; - u_int32_t ru_a, ru_b; - u_int32_t ru_g; - long ru_reseed; -}; - -static struct randomtab randomtab_32 = { - .ru_bits = 32, /* resulting bits */ - .ru_out = 180, /* Time after wich will be reseeded */ - .ru_max = 1000000000, /* Uniq cycle, avoid blackjack prediction */ - .ru_gen = 2, /* Starting generator */ - .ru_n = 2147483629, /* RU_N-1 = 2^2*3^2*59652323 */ - .ru_agen = 7, /* determine ru_a as RU_AGEN^(2*rand) */ - .ru_m = 1836660096, /* RU_M = 2^7*3^15 - don't change */ - .ru_pfacts = { 2, 3, 59652323, 0 }, /* factors of ru_n */ -}; - -static struct randomtab randomtab_20 = { - .ru_bits = 20, /* resulting bits */ - .ru_out = 180, /* Time after wich will be reseeded */ - .ru_max = 200000, /* Uniq cycle, avoid blackjack prediction */ - .ru_gen = 2, /* Starting generator */ - .ru_n = 524269, /* RU_N-1 = 2^2*3^2*14563 */ - .ru_agen = 7, /* determine ru_a as RU_AGEN^(2*rand) */ - .ru_m = 279936, /* RU_M = 2^7*3^7 - don't change */ - .ru_pfacts = { 2, 3, 14563, 0 }, /* factors of ru_n */ -}; - -static u_int32_t pmod(u_int32_t, u_int32_t, u_int32_t); -static void initid(struct randomtab *); -static u_int32_t randomid(struct randomtab *); - -/* - * Do a fast modular exponation, returned value will be in the range - * of 0 - (mod-1) - */ - -static u_int32_t -pmod(u_int32_t gen, u_int32_t expo, u_int32_t mod) -{ - u_int64_t s, t, u; - - s = 1; - t = gen; - u = expo; - - while (u) { - if (u & 1) - s = (s * t) % mod; - u >>= 1; - t = (t * t) % mod; - } - return (s); -} - -/* - * Initializes the seed and chooses a suitable generator. Also toggles - * the msb flag. The msb flag is used to generate two distinct - * cycles of random numbers and thus avoiding reuse of ids. - * - * This function is called from id_randomid() when needed, an - * application does not have to worry about it. - */ -static void -initid(struct randomtab *p) -{ - u_int32_t j, i; - int noprime = 1; - - p->ru_x = cprng_fast32() % p->ru_m; - - /* (bits - 1) bits of random seed */ - p->ru_seed = cprng_fast32() & (~0U >> (32 - p->ru_bits + 1)); - p->ru_seed2 = cprng_fast32() & (~0U >> (32 - p->ru_bits + 1)); - - /* Determine the LCG we use */ - p->ru_b = (cprng_fast32() & (~0U >> (32 - p->ru_bits))) | 1; - p->ru_a = pmod(p->ru_agen, - (cprng_fast32() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m); - while (p->ru_b % 3 == 0) - p->ru_b += 2; - - j = cprng_fast32() % p->ru_n; - - /* - * Do a fast gcd(j, RU_N - 1), so we can find a j with - * gcd(j, RU_N - 1) == 1, giving a new generator for - * RU_GEN^j mod RU_N - */ - while (noprime) { - for (i = 0; p->ru_pfacts[i] > 0; i++) - if (j % p->ru_pfacts[i] == 0) - break; - - if (p->ru_pfacts[i] == 0) - noprime = 0; - else - j = (j + 1) % p->ru_n; - } - - p->ru_g = pmod(p->ru_gen, j, p->ru_n); - p->ru_counter = 0; - - p->ru_reseed = time_uptime + p->ru_out; - p->ru_msb = p->ru_msb ? 0 : (1U << (p->ru_bits - 1)); -} - -static u_int32_t -randomid(struct randomtab *p) -{ - int i, n; - - if (p->ru_counter >= p->ru_max || time_uptime > p->ru_reseed) - initid(p); - - /* Skip a random number of ids */ - n = cprng_fast32() & 0x3; - if (p->ru_counter + n >= p->ru_max) - initid(p); - - for (i = 0; i <= n; i++) { - /* Linear Congruential Generator */ - p->ru_x = ((u_int64_t)p->ru_a * p->ru_x + p->ru_b) % p->ru_m; - } - - p->ru_counter += i; - - return (p->ru_seed ^ pmod(p->ru_g, p->ru_seed2 + p->ru_x, p->ru_n)) | - p->ru_msb; -} - -u_int32_t +uint32_t ip6_randomid(void) { - return randomid(&randomtab_32); + return cprng_fast32(); } -u_int32_t +uint32_t ip6_randomflowlabel(void) { - return randomid(&randomtab_20) & 0xfffff; + return cprng_fast32() & 0xfffff; }