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[src/trunk]: src/lib/libc use randomid(3). actually generate random ID for D...
details: https://anonhg.NetBSD.org/src/rev/e7b963bbce84
branches: trunk
changeset: 551646:e7b963bbce84
user: itojun <itojun%NetBSD.org@localhost>
date: Tue Sep 09 22:16:58 2003 +0000
description:
use randomid(3). actually generate random ID for DNS queries (previous
fix was incomplete)
diffstat:
lib/libc/net/res_init.c | 211 +-------------------------------------------
lib/libc/net/res_mkquery.c | 16 ++-
lib/libc/rpc/__rpc_getxid.c | 189 +++++----------------------------------
3 files changed, 40 insertions(+), 376 deletions(-)
diffs (truncated from 516 to 300 lines):
diff -r 0c0fd4d9e7cc -r e7b963bbce84 lib/libc/net/res_init.c
--- a/lib/libc/net/res_init.c Tue Sep 09 22:10:33 2003 +0000
+++ b/lib/libc/net/res_init.c Tue Sep 09 22:16:58 2003 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: res_init.c,v 1.44 2003/09/06 22:47:56 christos Exp $ */
+/* $NetBSD: res_init.c,v 1.45 2003/09/09 22:16:58 itojun Exp $ */
/*-
* Copyright (c) 1985, 1989, 1993
@@ -55,7 +55,7 @@
static char sccsid[] = "@(#)res_init.c 8.1 (Berkeley) 6/7/93";
static char rcsid[] = "Id: res_init.c,v 8.8 1997/06/01 20:34:37 vixie Exp ";
#else
-__RCSID("$NetBSD: res_init.c,v 1.44 2003/09/06 22:47:56 christos Exp $");
+__RCSID("$NetBSD: res_init.c,v 1.45 2003/09/09 22:16:58 itojun Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@@ -168,15 +168,6 @@
_res.retry = 4;
if (!(_res.options & RES_INIT))
_res.options = RES_DEFAULT;
-
- /*
- * This one used to initialize implicitly to zero, so unless the app
- * has set it to something in particular, we can randomize it now.
- */
- if (!_res.id)
- _res.id = res_randomid();
-#else
- _res.id = res_randomid();
#endif
#ifdef USELOOPBACK
@@ -579,201 +570,3 @@
return (htonl(IN_CLASSB_NET));
return (htonl(IN_CLASSC_NET));
}
-
-/* $OpenBSD: res_random.c,v 1.12 2002/06/27 10:14:02 itojun Exp $ */
-
-/*
- * Copyright 1997 Niels Provos <provos%physnet.uni-hamburg.de@localhost>
- * All rights reserved.
- *
- * Theo de Raadt <deraadt%openbsd.org@localhost> 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 15bit
- * 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 = 31104 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 15 bits, thus
- * yielding two different cycles by toggling the msb on and off.
- * This avoids reuse issues caused by reseeding.
- *
- * The 16 bit space is very small and brute force attempts are
- * entirly feasible, we skip a random number of transaction ids
- * so that an attacker will not get sequential ids.
- */
-
-#define RU_OUT 180 /* Time after wich will be reseeded */
-#define RU_MAX 30000 /* Uniq cycle, avoid blackjack prediction */
-#define RU_GEN 2 /* Starting generator */
-#define RU_N 32749 /* RU_N-1 = 2*2*3*2729 */
-#define RU_AGEN 7 /* determine ru_a as RU_AGEN^(2*rand) */
-#define RU_M 31104 /* RU_M = 2^7*3^5 - don't change */
-
-#define PFAC_N 3
-const static u_int16_t pfacts[PFAC_N] = {
- 2,
- 3,
- 2729
-};
-
-static u_int16_t ru_x;
-static u_int16_t ru_seed, ru_seed2;
-static u_int16_t ru_a, ru_b;
-static u_int16_t ru_g;
-static u_int16_t ru_counter = 0;
-static u_int16_t ru_msb = 0;
-static long ru_reseed;
-static u_int32_t ru_tmp; /* Storage for unused random */
-
-static u_int16_t pmod(u_int16_t, u_int16_t, u_int16_t);
-static void res_initid(void);
-
-/*
- * Do a fast modular exponation, returned value will be in the range
- * of 0 - (mod-1)
- */
-
-static u_int16_t
-pmod(u_int16_t gen, u_int16_t expo, u_int16_t mod)
-{
- u_int16_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 res_randomid() when needed, an
- * application does not have to worry about it.
- */
-static void
-res_initid(void)
-{
- u_int16_t j, i;
- int noprime = 1;
- struct timeval tv;
-
- ru_tmp = arc4random();
- ru_x = (ru_tmp & 0xFFFF) % RU_M;
-
- /* 15 bits of random seed */
- ru_seed = (ru_tmp >> 16) & 0x7FFF;
- ru_tmp = arc4random();
- ru_seed2 = ru_tmp & 0x7FFF;
-
- ru_tmp = arc4random();
-
- /* Determine the LCG we use */
- ru_b = (ru_tmp & 0xfffe) | 1;
- ru_a = pmod(RU_AGEN, (ru_tmp >> 16) & 0xfffe, RU_M);
- while (ru_b % 3 == 0)
- ru_b += 2;
-
- ru_tmp = arc4random();
- j = ru_tmp % RU_N;
- ru_tmp = ru_tmp >> 16;
-
- /*
- * 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; i < PFAC_N; i++)
- if (j % pfacts[i] == 0)
- break;
-
- if (i >= PFAC_N)
- noprime = 0;
- else
- j = (j + 1) % RU_N;
- }
-
- ru_g = pmod(RU_GEN, j, RU_N);
- ru_counter = 0;
-
- gettimeofday(&tv, NULL);
- ru_reseed = tv.tv_sec + RU_OUT;
- ru_msb = ru_msb == 0x8000 ? 0 : 0x8000;
-}
-
-u_int
-res_randomid(void)
-{
- int i, n;
- struct timeval tv;
-
- gettimeofday(&tv, NULL);
- if (ru_counter >= RU_MAX || tv.tv_sec > ru_reseed)
- res_initid();
-
- if (!ru_tmp)
- ru_tmp = arc4random();
-
- /* Skip a random number of ids */
- n = ru_tmp & 0x7; ru_tmp = ru_tmp >> 3;
- if (ru_counter + n >= RU_MAX)
- res_initid();
-
- for (i = 0; i <= n; i++) {
- /* Linear Congruential Generator */
- ru_x = (ru_a * ru_x + ru_b) % RU_M;
- }
-
- ru_counter += i;
-
- return (ru_seed ^ pmod(ru_g, ru_seed2 ^ ru_x, RU_N)) | ru_msb;
-}
diff -r 0c0fd4d9e7cc -r e7b963bbce84 lib/libc/net/res_mkquery.c
--- a/lib/libc/net/res_mkquery.c Tue Sep 09 22:10:33 2003 +0000
+++ b/lib/libc/net/res_mkquery.c Tue Sep 09 22:16:58 2003 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: res_mkquery.c,v 1.24 2003/08/07 16:43:14 agc Exp $ */
+/* $NetBSD: res_mkquery.c,v 1.25 2003/09/09 22:16:58 itojun Exp $ */
/*-
* Copyright (c) 1985, 1993
@@ -55,7 +55,7 @@
static char sccsid[] = "@(#)res_mkquery.c 8.1 (Berkeley) 6/4/93";
static char rcsid[] = "Id: res_mkquery.c,v 8.5 1996/08/27 08:33:28 vixie Exp ";
#else
-__RCSID("$NetBSD: res_mkquery.c,v 1.24 2003/08/07 16:43:14 agc Exp $");
+__RCSID("$NetBSD: res_mkquery.c,v 1.25 2003/09/09 22:16:58 itojun Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@@ -72,6 +72,7 @@
#include <resolv.h>
#include <stdio.h>
#include <string.h>
+#include <randomid.h>
#if defined(_LIBC) && defined(__weak_alias)
__weak_alias(res_mkquery,_res_mkquery)
@@ -97,11 +98,20 @@
register u_char *cp, *ep;
register int n;
u_char *dnptrs[20], **dpp, **lastdnptr;
+ static randomid_t ctx = NULL;;
_DIAGASSERT(dname != NULL);
/* data may be NULL */
/* newrr_in is not used */
+ if (!ctx) {
+ ctx = randomid_new(16, RANDOMID_TIMEO_DEFAULT);
+ if (!ctx) {
+ h_errno = NETDB_INTERNAL;
+ return (-1);
+ }
+ }
+
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (-1);
@@ -127,7 +137,7 @@
return(-1);
(void)memset(buf, 0, HFIXEDSZ);
hp = (HEADER *)(void *)buf;
- hp->id = htons(++_res.id);
+ hp->id = htons(_res.id = (u_short)randomid(ctx));
hp->opcode = op;
hp->rd = (_res.options & RES_RECURSE) != 0;
hp->rcode = NOERROR;
diff -r 0c0fd4d9e7cc -r e7b963bbce84 lib/libc/rpc/__rpc_getxid.c
--- a/lib/libc/rpc/__rpc_getxid.c Tue Sep 09 22:10:33 2003 +0000
+++ b/lib/libc/rpc/__rpc_getxid.c Tue Sep 09 22:16:58 2003 +0000
@@ -1,15 +1,10 @@
-/* $NetBSD: __rpc_getxid.c,v 1.1 2003/09/09 03:56:23 itojun Exp $ */
+/* $NetBSD: __rpc_getxid.c,v 1.2 2003/09/09 22:16:58 itojun Exp $ */
/* $OpenBSD: ip_id.c,v 1.6 2002/03/15 18:19:52 millert Exp $ */
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