randomize IPv6 fragment ID.
Obtained from: KAME
This commit is contained in:
Hajimu UMEMOTO
parent
1313b38492
commit
8373d51d4b
@ -1456,6 +1456,7 @@ netinet6/in6_rmx.c optional inet6
|
||||
netinet6/in6_src.c optional inet6
|
||||
netinet6/ip6_forward.c optional inet6
|
||||
netinet6/ip6_fw.c optional inet6 ipv6firewall
|
||||
netinet6/ip6_id.c optional inet6
|
||||
netinet6/ip6_input.c optional inet6
|
||||
netinet6/ip6_mroute.c optional inet6
|
||||
netinet6/ip6_output.c optional inet6
|
||||
|
||||
247
sys/netinet6/ip6_id.c
Normal file
247
sys/netinet6/ip6_id.c
Normal file
@ -0,0 +1,247 @@
|
||||
/* $KAME: ip6_id.c,v 1.13 2003/09/16 09:11:19 itojun Exp $ */
|
||||
/* $OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $ */
|
||||
/* $FreeBSD$ */
|
||||
|
||||
/*
|
||||
* Copyright (C) 2003 WIDE Project.
|
||||
* All rights reserved.
|
||||
*
|
||||
* 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.
|
||||
* 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 <provos@citi.umich.edu>
|
||||
* All rights reserved.
|
||||
*
|
||||
* Theo de Raadt <deraadt@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.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by Niels Provos.
|
||||
* 4. The name of the author may not be used to endorse or promote products
|
||||
* derived from this software without specific prior written permission.
|
||||
*
|
||||
* 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)
|
||||
*
|
||||
* Effectivly 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.
|
||||
*/
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <sys/param.h>
|
||||
#include <sys/kernel.h>
|
||||
#include <sys/socket.h>
|
||||
#include <sys/libkern.h>
|
||||
|
||||
#include <net/if.h>
|
||||
#include <net/route.h>
|
||||
#include <netinet/in.h>
|
||||
#include <netinet/ip6.h>
|
||||
#include <netinet6/ip6_var.h>
|
||||
|
||||
#ifndef INT32_MAX
|
||||
#define INT32_MAX 0x7fffffffU
|
||||
#endif
|
||||
|
||||
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 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 = {
|
||||
32, /* resulting bits */
|
||||
180, /* Time after wich will be reseeded */
|
||||
1000000000, /* Uniq cycle, avoid blackjack prediction */
|
||||
2, /* Starting generator */
|
||||
2147483629, /* RU_N-1 = 2^2*3^2*59652323 */
|
||||
7, /* determine ru_a as RU_AGEN^(2*rand) */
|
||||
1836660096, /* RU_M = 2^7*3^15 - don't change */
|
||||
{ 2, 3, 59652323, 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);
|
||||
}
|
||||
|
||||
/*
|
||||
* Initalizes 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 = arc4random() % p->ru_m;
|
||||
|
||||
/* (bits - 1) bits of random seed */
|
||||
p->ru_seed = arc4random() & (~0U >> (32 - p->ru_bits + 1));
|
||||
p->ru_seed2 = arc4random() & (~0U >> (32 - p->ru_bits + 1));
|
||||
|
||||
/* Determine the LCG we use */
|
||||
p->ru_b = (arc4random() & (~0U >> (32 - p->ru_bits))) | 1;
|
||||
p->ru_a = pmod(p->ru_agen,
|
||||
(arc4random() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
|
||||
while (p->ru_b % 3 == 0)
|
||||
p->ru_b += 2;
|
||||
|
||||
j = arc4random() % 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->pfacts[i] > 0; i++)
|
||||
if (j % p->pfacts[i] == 0)
|
||||
break;
|
||||
|
||||
if (p->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_second + 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;
|
||||
u_int32_t tmp;
|
||||
|
||||
if (p->ru_counter >= p->ru_max || time_second > p->ru_reseed)
|
||||
initid(p);
|
||||
|
||||
tmp = arc4random();
|
||||
|
||||
/* Skip a random number of ids */
|
||||
n = tmp & 0x3; tmp = tmp >> 2;
|
||||
if (p->ru_counter + n >= p->ru_max)
|
||||
initid(p);
|
||||
|
||||
for (i = 0; i <= n; i++) {
|
||||
/* Linear Congruential Generator */
|
||||
p->ru_x = (u_int32_t)((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
|
||||
ip6_randomid(void)
|
||||
{
|
||||
|
||||
return randomid(&randomtab_32);
|
||||
}
|
||||
@ -978,7 +978,7 @@ skip_ipsec2:;
|
||||
} else {
|
||||
struct mbuf **mnext, *m_frgpart;
|
||||
struct ip6_frag *ip6f;
|
||||
u_int32_t id = htonl(ip6_id++);
|
||||
u_int32_t id = htonl(ip6_randomid());
|
||||
u_char nextproto;
|
||||
|
||||
/*
|
||||
|
||||
@ -352,6 +352,8 @@ int rip6_usrreq __P((struct socket *,
|
||||
|
||||
int dest6_input __P((struct mbuf **, int *, int));
|
||||
int none_input __P((struct mbuf **, int *, int));
|
||||
|
||||
u_int32_t ip6_randomid __P((void));
|
||||
#endif /* _KERNEL */
|
||||
|
||||
#endif /* !_NETINET6_IP6_VAR_H_ */
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user