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Code Issues Releases Wiki Activity

2203. [security] Query id generation was cryptographically weak.

Browse Source 
[RT # 16915]
This commit is contained in:
Mark Andrews 2007-06-26 02:52:15 +00:00
parent 5c6d6dd33b
commit 07072c9456
4 changed files with 472 additions and 56 deletions
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3
CHANGES
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@ -1,3 +1,6 @@
2203. [security] Query id generation was cryptographically weak.
[RT # 16915]
2202. [security] The default acls for allow-query-cache and
allow-recursion were not being applied. [RT #16960]

10
bin/named/client.c
View File

@ -15,7 +15,7 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: client.c,v 1.247 2007/06/18 23:47:18 tbox Exp $ */
/* $Id: client.c,v 1.248 2007/06/26 02:52:15 marka Exp $ */
#include <config.h>
@ -1439,6 +1439,14 @@ client_request(isc_task_t *task, isc_event_t *event) {
}
}
/*
* Hash the incoming request here as it is after
* dns_dispatch_importrecv().
*/
dns_dispatch_hash(&client->now, sizeof(client->now));
dns_dispatch_hash(isc_buffer_base(buffer),
isc_buffer_usedlength(buffer));
/*
* It's a request. Parse it.
*/

506
lib/dns/dispatch.c
View File

@ -15,16 +15,17 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: dispatch.c,v 1.133 2007/06/18 23:47:40 tbox Exp $ */
/* $Id: dispatch.c,v 1.134 2007/06/26 02:52:15 marka Exp $ */
/*! \file */
#include <config.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <isc/entropy.h>
#include <isc/lfsr.h>
#include <isc/mem.h>
#include <isc/mutex.h>
#include <isc/print.h>
@ -43,13 +44,22 @@
typedef ISC_LIST(dns_dispentry_t) dns_displist_t;
typedef struct dns_nsid {
isc_uint16_t nsid_state;
isc_uint16_t *nsid_vtable;
isc_uint16_t *nsid_pool;
isc_uint16_t nsid_a1, nsid_a2, nsid_a3;
isc_uint16_t nsid_c1, nsid_c2, nsid_c3;
isc_uint16_t nsid_state2;
isc_boolean_t nsid_usepool;
} dns_nsid_t;
typedef struct dns_qid {
unsigned int magic;
unsigned int qid_nbuckets; /*%< hash table size */
unsigned int qid_increment; /*%< id increment on collision */
isc_mutex_t lock;
isc_lfsr_t qid_lfsr1; /*%< state generator info */
isc_lfsr_t qid_lfsr2; /*%< state generator info */
dns_nsid_t nsid;
dns_displist_t *qid_table; /*%< the table itself */
} dns_qid_t;
@ -158,7 +168,7 @@ static void destroy_disp(isc_task_t *task, isc_event_t *event);
static void udp_recv(isc_task_t *, isc_event_t *);
static void tcp_recv(isc_task_t *, isc_event_t *);
static void startrecv(dns_dispatch_t *);
static dns_messageid_t dns_randomid(dns_qid_t *);
static dns_messageid_t dns_randomid(dns_nsid_t *);
static isc_uint32_t dns_hash(dns_qid_t *, isc_sockaddr_t *, dns_messageid_t);
static void free_buffer(dns_dispatch_t *disp, void *buf, unsigned int len);
static void *allocate_udp_buffer(dns_dispatch_t *disp);
@ -179,8 +189,12 @@ static isc_result_t dispatch_createudp(dns_dispatchmgr_t *mgr,
static isc_boolean_t destroy_mgr_ok(dns_dispatchmgr_t *mgr);
static void destroy_mgr(dns_dispatchmgr_t **mgrp);
static isc_result_t qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets,
unsigned int increment, dns_qid_t **qidp);
unsigned int increment, isc_boolean_t usepool,
dns_qid_t **qidp);
static void qid_destroy(isc_mem_t *mctx, dns_qid_t **qidp);
static isc_uint16_t nsid_next(dns_nsid_t *nsid);
static isc_result_t nsid_init(isc_mem_t *mctx, dns_nsid_t *nsid, isc_boolean_t usepool);
static void nsid_destroy(isc_mem_t *mctx, dns_nsid_t *nsid);
#define LVL(x) ISC_LOG_DEBUG(x)
@ -260,37 +274,15 @@ request_log(dns_dispatch_t *disp, dns_dispentry_t *resp,
}
}
static void
reseed_lfsr(isc_lfsr_t *lfsr, void *arg)
{
dns_dispatchmgr_t *mgr = arg;
isc_result_t result;
isc_uint32_t val;
REQUIRE(VALID_DISPATCHMGR(mgr));
if (mgr->entropy != NULL) {
result = isc_entropy_getdata(mgr->entropy, &val, sizeof(val),
NULL, 0);
INSIST(result == ISC_R_SUCCESS);
lfsr->count = (val & 0x1f) + 32;
lfsr->state = val;
return;
}
lfsr->count = (random() & 0x1f) + 32; /* From 32 to 63 states */
lfsr->state = random();
}
/*
* Return an unpredictable non-reserved UDP port. We share the QID
* framework for this purpose.
*/
static in_port_t
get_randomport(dns_qid_t *qid) {
isc_uint32_t p;
get_randomport(dns_nsid_t *nsid) {
isc_uint16_t p;
p = isc_lfsr_generate32(&qid->qid_lfsr1, &qid->qid_lfsr2);
p = nsid_next(nsid);
/* XXX: should the range be configurable? */
return ((in_port_t)(1024 + (p % (65535 - 1024))));
@ -300,12 +292,12 @@ get_randomport(dns_qid_t *qid) {
* Return an unpredictable message ID.
*/
static dns_messageid_t
dns_randomid(dns_qid_t *qid) {
dns_randomid(dns_nsid_t *nsid) {
isc_uint32_t id;
id = isc_lfsr_generate32(&qid->qid_lfsr1, &qid->qid_lfsr2);
id = nsid_next(nsid);
return (dns_messageid_t)(id & 0xFFFF);
return ((dns_messageid_t)id);
}
/*
@ -645,6 +637,9 @@ udp_recv(isc_task_t *task, isc_event_t *ev_in) {
goto restart;
}
dns_dispatch_hash(&ev->timestamp, sizeof(&ev->timestamp));
dns_dispatch_hash(ev->region.base, ev->region.length);
/* response */
bucket = dns_hash(qid, &ev->address, id);
LOCK(&qid->lock);
@ -879,6 +874,8 @@ tcp_recv(isc_task_t *task, isc_event_t *ev_in) {
goto restart;
}
dns_dispatch_hash(tcpmsg->buffer.base, tcpmsg->buffer.length);
/*
* Response.
*/
@ -1267,7 +1264,7 @@ dns_dispatchmgr_setudp(dns_dispatchmgr_t *mgr,
isc_mempool_setmaxalloc(mgr->bpool, maxbuffers);
isc_mempool_associatelock(mgr->bpool, &mgr->pool_lock);
result = qid_allocate(mgr, buckets, increment, &mgr->qid);
result = qid_allocate(mgr, buckets, increment, ISC_TRUE, &mgr->qid);
if (result != ISC_R_SUCCESS)
goto cleanup;
@ -1419,7 +1416,7 @@ dispatch_find(dns_dispatchmgr_t *mgr, isc_sockaddr_t *local,
static isc_result_t
qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets,
unsigned int increment, dns_qid_t **qidp)
unsigned int increment, isc_boolean_t usepool, dns_qid_t **qidp)
{
dns_qid_t *qid;
unsigned int i;
@ -1441,8 +1438,17 @@ qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets,
return (ISC_R_NOMEMORY);
}
result = nsid_init(mgr->mctx, &qid->nsid, usepool);
if (result != ISC_R_SUCCESS) {
isc_mem_put(mgr->mctx, qid->qid_table,
buckets * sizeof(dns_displist_t));
isc_mem_put(mgr->mctx, qid, sizeof(*qid));
return (ISC_R_NOMEMORY);
}
result = isc_mutex_init(&qid->lock);
if (result != ISC_R_SUCCESS) {
nsid_destroy(mgr->mctx, &qid->nsid);
isc_mem_put(mgr->mctx, qid->qid_table,
buckets * sizeof(dns_displist_t));
isc_mem_put(mgr->mctx, qid, sizeof(*qid));
@ -1455,21 +1461,6 @@ qid_allocate(dns_dispatchmgr_t *mgr, unsigned int buckets,
qid->qid_nbuckets = buckets;
qid->qid_increment = increment;
qid->magic = QID_MAGIC;
/*
* Initialize to a 32-bit LFSR. Both of these are from Applied
* Cryptography.
*
* lfsr1:
* x^32 + x^7 + x^5 + x^3 + x^2 + x + 1
*
* lfsr2:
* x^32 + x^7 + x^6 + x^2 + 1
*/
isc_lfsr_init(&qid->qid_lfsr1, 0, 32, 0x80000057U,
0, reseed_lfsr, mgr);
isc_lfsr_init(&qid->qid_lfsr2, 0, 32, 0x80000062U,
0, reseed_lfsr, mgr);
*qidp = qid;
return (ISC_R_SUCCESS);
}
@ -1485,6 +1476,7 @@ qid_destroy(isc_mem_t *mctx, dns_qid_t **qidp) {
*qidp = NULL;
qid->magic = 0;
nsid_destroy(mctx, &qid->nsid);
isc_mem_put(mctx, qid->qid_table,
qid->qid_nbuckets * sizeof(dns_displist_t));
DESTROYLOCK(&qid->lock);
@ -1626,7 +1618,7 @@ dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socket_t *sock,
return (result);
}
result = qid_allocate(mgr, buckets, increment, &disp->qid);
result = qid_allocate(mgr, buckets, increment, ISC_FALSE, &disp->qid);
if (result != ISC_R_SUCCESS)
goto deallocate_dispatch;
@ -1802,7 +1794,7 @@ dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
getsocket:
if ((attributes & DNS_DISPATCHATTR_RANDOMPORT) != 0) {
isc_sockaddr_setport(&localaddr_bound,
get_randomport(mgr->qid));
get_randomport(&mgr->qid->nsid));
if (blacklisted(mgr, NULL, &localaddr_bound)) {
if (++k == 1024)
attributes &= ~DNS_DISPATCHATTR_RANDOMPORT;
@ -1976,7 +1968,7 @@ dns_dispatch_addresponse(dns_dispatch_t *disp, isc_sockaddr_t *dest,
*/
qid = DNS_QID(disp);
LOCK(&qid->lock);
id = dns_randomid(qid);
id = dns_randomid(&qid->nsid);
bucket = dns_hash(qid, dest, id);
ok = ISC_FALSE;
for (i = 0; i < 64; i++) {
@ -2319,3 +2311,409 @@ dns_dispatchmgr_dump(dns_dispatchmgr_t *mgr) {
}
}
#endif
/*
* Allow the user to pick one of two ID randomization algorithms.
*
* The first algorithm is an adaptation of the sequence shuffling
* algorithm discovered by Carter Bays and S. D. Durham [ACM Trans. Math.
* Software 2 (1976), 59-64], as documented as Algorithm B in Chapter
* 3.2.2 in Volume 2 of Knuth's "The Art of Computer Programming". We use
* a randomly selected linear congruential random number generator with a
* modulus of 2^16, whose increment is a randomly picked odd number, and
* whose multiplier is picked from a set which meets the following
* criteria:
* Is of the form 8*n+5, which ensures "high potency" according to
* principle iii in the summary chapter 3.6. This form also has a
* gcd(a-1,m) of 4 which is good according to principle iv.
*
* Is between 0.01 and 0.99 times the modulus as specified by
* principle iv.
*
* Passes the spectral test "with flying colors" (ut >= 1) in
* dimensions 2 through 6 as calculated by Algorithm S in Chapter
* 3.3.4 and the ratings calculated by formula 35 in section E.
*
* Of the multipliers that pass this test, pick the set that is
* best according to the theoretical bounds of the serial
* correlation test. This was calculated using a simplified
* version of Knuth's Theorem K in Chapter 3.3.3.
*
* These criteria may not be important for this use, but we might as well
* pick from the best generators since there are so many possible ones and
* we don't have that many random bits to do the picking.
*
* We use a modulus of 2^16 instead of something bigger so that we will
* tend to cycle through all the possible IDs before repeating any,
* however the shuffling will perturb this somewhat. Theoretically there
* is no minimimum interval between two uses of the same ID, but in
* practice it seems to be >64000.
*
* Our adaptatation of Algorithm B mixes the hash state which has
* captured various random events into the shuffler to perturb the
* sequence.
*
* One disadvantage of this algorithm is that if the generator parameters
* were to be guessed, it would be possible to mount a limited brute force
* attack on the ID space since the IDs are only shuffled within a limited
* range.
*
* The second algorithm uses the same random number generator to populate
* a pool of 65536 IDs. The hash state is used to pick an ID from a window
* of 4096 IDs in this pool, then the chosen ID is swapped with the ID
* at the beginning of the window and the window position is advanced.
* This means that the interval between uses of the ID will be no less
* than 65536-4096. The ID sequence in the pool will become more random
* over time.
*
* For both algorithms, two more linear congruential random number generators
* are selected. The ID from the first part of algorithm is used to seed
* the first of these generators, and its output is used to seed the second.
* The strategy is use these generators as 1 to 1 hashes to obfuscate the
* properties of the generator used in the first part of either algorithm.
*
* The first algorithm may be suitable for use in a client resolver since
* its memory requirements are fairly low and it's pretty random out of
* the box. It is somewhat succeptible to a limited brute force attack,
* so the second algorithm is probably preferable for a longer running
* program that issues a large number of queries and has time to randomize
* the pool.
*/
#define NSID_SHUFFLE_TABLE_SIZE 100 /* Suggested by Knuth */
/*
* Pick one of the next 4096 IDs in the pool.
* There is a tradeoff here between randomness and how often and ID is reused.
*/
#define NSID_LOOKAHEAD 4096 /* Must be a power of 2 */
#define NSID_SHUFFLE_ONLY 1 /* algorithm 1 */
#define NSID_USE_POOL 2 /* algorithm 2 */
#define NSID_HASHSHIFT 3
#define NSID_HASHROTATE(v) \
(((v) << NSID_HASHSHIFT) | ((v) >> ((sizeof(v) * 8) - NSID_HASHSHIFT)))
static isc_uint32_t nsid_hash_state;
/*
* Keep a running hash of various bits of data that we'll use to
* stir the ID pool or perturb the ID generator
*/
static void
nsid_hash(void *data, size_t len) {
unsigned char *p = data;
/*
* Hash function similar to the one we use for hashing names.
* We don't fold case or toss the upper bit here, though.
* This hash doesn't do much interesting when fed binary zeros,
* so there may be a better hash function.
* This function doesn't need to be very strong since we're
* only using it to stir the pool, but it should be reasonably
* fast.
*/
/*
* We don't care about locking access to nsid_hash_state.
* In fact races make the result even more non deteministic.
*/
while (len-- > 0) {
nsid_hash_state = NSID_HASHROTATE(nsid_hash_state);
nsid_hash_state += *p++;
}
}
/*
* Table of good linear congruential multipliers for modulus 2^16
* in order of increasing serial correlation bounds (so trim from
* the end).
*/
static const isc_uint16_t nsid_multiplier_table[] = {
17565, 25013, 11733, 19877, 23989, 23997, 24997, 25421,
26781, 27413, 35901, 35917, 35973, 36229, 38317, 38437,
39941, 40493, 41853, 46317, 50581, 51429, 53453, 53805,
11317, 11789, 12045, 12413, 14277, 14821, 14917, 18989,
19821, 23005, 23533, 23573, 23693, 27549, 27709, 28461,
29365, 35605, 37693, 37757, 38309, 41285, 45261, 47061,
47269, 48133, 48597, 50277, 50717, 50757, 50805, 51341,
51413, 51581, 51597, 53445, 11493, 14229, 20365, 20653,
23485, 25541, 27429, 29421, 30173, 35445, 35653, 36789,
36797, 37109, 37157, 37669, 38661, 39773, 40397, 41837,
41877, 45293, 47277, 47845, 49853, 51085, 51349, 54085,
56933, 8877, 8973, 9885, 11365, 11813, 13581, 13589,
13613, 14109, 14317, 15765, 15789, 16925, 17069, 17205,
17621, 17941, 19077, 19381, 20245, 22845, 23733, 24869,
25453, 27213, 28381, 28965, 29245, 29997, 30733, 30901,
34877, 35485, 35613, 36133, 36661, 36917, 38597, 40285,
40693, 41413, 41541, 41637, 42053, 42349, 45245, 45469,
46493, 48205, 48613, 50861, 51861, 52877, 53933, 54397,
55669, 56453, 56965, 58021, 7757, 7781, 8333, 9661,
12229, 14373, 14453, 17549, 18141, 19085, 20773, 23701,
24205, 24333, 25261, 25317, 27181, 30117, 30477, 34757,
34885, 35565, 35885, 36541, 37957, 39733, 39813, 41157,
41893, 42317, 46621, 48117, 48181, 49525, 55261, 55389,
56845, 7045, 7749, 7965, 8469, 9133, 9549, 9789,
10173, 11181, 11285, 12253, 13453, 13533, 13757, 14477,
15053, 16901, 17213, 17269, 17525, 17629, 18605, 19013,
19829, 19933, 20069, 20093, 23261, 23333, 24949, 25309,
27613, 28453, 28709, 29301, 29541, 34165, 34413, 37301,
37773, 38045, 38405, 41077, 41781, 41925, 42717, 44437,
44525, 44613, 45933, 45941, 47077, 50077, 50893, 52117,
5293, 55069, 55989, 58125, 59205, 6869, 14685, 15453,
16821, 17045, 17613, 18437, 21029, 22773, 22909, 25445,
25757, 26541, 30709, 30909, 31093, 31149, 37069, 37725,
37925, 38949, 39637, 39701, 40765, 40861, 42965, 44813,
45077, 45733, 47045, 50093, 52861, 52957, 54181, 56325,
56365, 56381, 56877, 57013, 5741, 58101, 58669, 8613,
10045, 10261, 10653, 10733, 11461, 12261, 14069, 15877,
17757, 21165, 23885, 24701, 26429, 26645, 27925, 28765,
29197, 30189, 31293, 39781, 39909, 40365, 41229, 41453,
41653, 42165, 42365, 47421, 48029, 48085, 52773, 5573,
57037, 57637, 58341, 58357, 58901, 6357, 7789, 9093,
10125, 10709, 10765, 11957, 12469, 13437, 13509, 14773,
15437, 15773, 17813, 18829, 19565, 20237, 23461, 23685,
23725, 23941, 24877, 25461, 26405, 29509, 30285, 35181,
37229, 37893, 38565, 40293, 44189, 44581, 45701, 47381,
47589, 48557, 4941, 51069, 5165, 52797, 53149, 5341,
56301, 56765, 58581, 59493, 59677, 6085, 6349, 8293,
8501, 8517, 11597, 11709, 12589, 12693, 13517, 14909,
17397, 18085, 21101, 21269, 22717, 25237, 25661, 29189,
30101, 31397, 33933, 34213, 34661, 35533, 36493, 37309,
40037, 4189, 42909, 44309, 44357, 44389, 4541, 45461,
46445, 48237, 54149, 55301, 55853, 56621, 56717, 56901,
5813, 58437, 12493, 15365, 15989, 17829, 18229, 19341,
21013, 21357, 22925, 24885, 26053, 27581, 28221, 28485,
30605, 30613, 30789, 35437, 36285, 37189, 3941, 41797,
4269, 42901, 43293, 44645, 45221, 46893, 4893, 50301,
50325, 5189, 52109, 53517, 54053, 54485, 5525, 55949,
56973, 59069, 59421, 60733, 61253, 6421, 6701, 6709,
7101, 8669, 15797, 19221, 19837, 20133, 20957, 21293,
21461, 22461, 29085, 29861, 30869, 34973, 36469, 37565,
38125, 38829, 39469, 40061, 40117, 44093, 47429, 48341,
50597, 51757, 5541, 57629, 58405, 59621, 59693, 59701,
61837, 7061, 10421, 11949, 15405, 20861, 25397, 25509,
25893, 26037, 28629, 28869, 29605, 30213, 34205, 35637,
36365, 37285, 3773, 39117, 4021, 41061, 42653, 44509,
4461, 44829, 4725, 5125, 52269, 56469, 59085, 5917,
60973, 8349, 17725, 18637, 19773, 20293, 21453, 22533,
24285, 26333, 26997, 31501, 34541, 34805, 37509, 38477,
41333, 44125, 46285, 46997, 47637, 48173, 4925, 50253,
50381, 50917, 51205, 51325, 52165, 52229, 5253, 5269,
53509, 56253, 56341, 5821, 58373, 60301, 61653, 61973,
62373, 8397, 11981, 14341, 14509, 15077, 22261, 22429,
24261, 28165, 28685, 30661, 34021, 34445, 39149, 3917,
43013, 43317, 44053, 44101, 4533, 49541, 49981, 5277,
54477, 56357, 57261, 57765, 58573, 59061, 60197, 61197,
62189, 7725, 8477, 9565, 10229, 11437, 14613, 14709,
16813, 20029, 20677, 31445, 3165, 31957, 3229, 33541,
36645, 3805, 38973, 3965, 4029, 44293, 44557, 46245,
48917, 4909, 51749, 53709, 55733, 56445, 5925, 6093,
61053, 62637, 8661, 9109, 10821, 11389, 13813, 14325,
15501, 16149, 18845, 22669, 26437, 29869, 31837, 33709,
33973, 34173, 3677, 3877, 3981, 39885, 42117, 4421,
44221, 44245, 44693, 46157, 47309, 5005, 51461, 52037,
55333, 55693, 56277, 58949, 6205, 62141, 62469, 6293,
10101, 12509, 14029, 17997, 20469, 21149, 25221, 27109,
2773, 2877, 29405, 31493, 31645, 4077, 42005, 42077,
42469, 42501, 44013, 48653, 49349, 4997, 50101, 55405,
56957, 58037, 59429, 60749, 61797, 62381, 62837, 6605,
10541, 23981, 24533, 2701, 27333, 27341, 31197, 33805,
3621, 37381, 3749, 3829, 38533, 42613, 44381, 45901,
48517, 51269, 57725, 59461, 60045, 62029, 13805, 14013,
15461, 16069, 16157, 18573, 2309, 23501, 28645, 3077,
31541, 36357, 36877, 3789, 39429, 39805, 47685, 47949,
49413, 5485, 56757, 57549, 57805, 58317, 59549, 62213,
62613, 62853, 62933, 8909, 12941, 16677, 20333, 21541,
24429, 26077, 26421, 2885, 31269, 33381, 3661, 40925,
42925, 45173, 4525, 4709, 53133, 55941, 57413, 57797,
62125, 62237, 62733, 6773, 12317, 13197, 16533, 16933,
18245, 2213, 2477, 29757, 33293, 35517, 40133, 40749,
4661, 49941, 62757, 7853, 8149, 8573, 11029, 13421,
21549, 22709, 22725, 24629, 2469, 26125, 2669, 34253,
36709, 41013, 45597, 46637, 52285, 52333, 54685, 59013,
60997, 61189, 61981, 62605, 62821, 7077, 7525, 8781,
10861, 15277, 2205, 22077, 28517, 28949, 32109, 33493,
4661, 49941, 62757, 7853, 8149, 8573, 11029, 13421,
21549, 22709, 22725, 24629, 2469, 26125, 2669, 34253,
36709, 41013, 45597, 46637, 52285, 52333, 54685, 59013,
60997, 61189, 61981, 62605, 62821, 7077, 7525, 8781,
10861, 15277, 2205, 22077, 28517, 28949, 32109, 33493,
3685, 39197, 39869, 42621, 44997, 48565, 5221, 57381,
61749, 62317, 63245, 63381, 23149, 2549, 28661, 31653,
33885, 36341, 37053, 39517, 42805, 45853, 48997, 59349,
60053, 62509, 63069, 6525, 1893, 20181, 2365, 24893,
27397, 31357, 32277, 33357, 34437, 36677, 37661, 43469,
43917, 50997, 53869, 5653, 13221, 16741, 17893, 2157,
28653, 31789, 35301, 35821, 61613, 62245, 12405, 14517,
17453, 18421, 3149, 3205, 40341, 4109, 43941, 46869,
48837, 50621, 57405, 60509, 62877, 8157, 12933, 12957,
16501, 19533, 3461, 36829, 52357, 58189, 58293, 63053,
17109, 1933, 32157, 37701, 59005, 61621, 13029, 15085,
16493, 32317, 35093, 5061, 51557, 62221, 20765, 24613,
2629, 30861, 33197, 33749, 35365, 37933, 40317, 48045,
56229, 61157, 63797, 7917, 17965, 1917, 1973, 20301,
2253, 33157, 58629, 59861, 61085, 63909, 8141, 9221,
14757, 1581, 21637, 26557, 33869, 34285, 35733, 40933,
42517, 43501, 53653, 61885, 63805, 7141, 21653, 54973,
31189, 60061, 60341, 63357, 16045, 2053, 26069, 33997,
43901, 54565, 63837, 8949, 17909, 18693, 32349, 33125,
37293, 48821, 49053, 51309, 64037, 7117, 1445, 20405,
23085, 26269, 26293, 27349, 32381, 33141, 34525, 36461,
37581, 43525, 4357, 43877, 5069, 55197, 63965, 9845,
12093, 2197, 2229, 32165, 33469, 40981, 42397, 8749,
10853, 1453, 18069, 21693, 30573, 36261, 37421, 42533
};
#define NSID_MULT_TABLE_SIZE \
((sizeof nsid_multiplier_table)/(sizeof nsid_multiplier_table[0]))
#define NSID_RANGE_MASK (NSID_LOOKAHEAD - 1)
#define NSID_POOL_MASK 0xFFFF /* used to wrap the pool index */
#define NSID_SHUFFLE_ONLY 1
#define NSID_USE_POOL 2
static isc_uint16_t
nsid_next(dns_nsid_t *nsid) {
isc_uint16_t id, compressed_hash;
isc_uint16_t j;
compressed_hash = ((nsid_hash_state >> 16) ^
(nsid_hash_state)) & 0xFFFF;
if (nsid->nsid_usepool) {
u_int16_t pick;
pick = compressed_hash & NSID_RANGE_MASK;
pick = (nsid->nsid_state + pick) & NSID_POOL_MASK;
id = nsid->nsid_pool[pick];
if (pick != 0) {
/* Swap two IDs to stir the pool */
nsid->nsid_pool[pick] =
nsid->nsid_pool[nsid->nsid_state];
nsid->nsid_pool[nsid->nsid_state] = id;
}
/* increment the base pointer into the pool */
if (nsid->nsid_state == 65535)
nsid->nsid_state = 0;
else
nsid->nsid_state++;
} else {
/*
* This is the original Algorithm B
* j = ((u_long) NSID_SHUFFLE_TABLE_SIZE * nsid_state2) >> 16;
*
* We'll perturb it with some random stuff ...
*/
j = ((isc_uint32_t) NSID_SHUFFLE_TABLE_SIZE *
(nsid->nsid_state2 ^ compressed_hash)) >> 16;
nsid->nsid_state2 = id = nsid->nsid_vtable[j];
nsid->nsid_state = (((isc_uint32_t) nsid->nsid_a1 * nsid->nsid_state) +
nsid->nsid_c1) & 0xFFFF;
nsid->nsid_vtable[j] = nsid->nsid_state;
}
/* Now lets obfuscate ... */
id = (((isc_uint32_t) nsid->nsid_a2 * id) + nsid->nsid_c2) & 0xFFFF;
id = (((isc_uint32_t) nsid->nsid_a3 * id) + nsid->nsid_c3) & 0xFFFF;
return (id);
}
static isc_result_t
nsid_init(isc_mem_t *mctx, dns_nsid_t *nsid, isc_boolean_t usepool) {
struct timeval now;
pid_t mypid;
isc_uint16_t a1ndx, a2ndx, a3ndx, c1ndx, c2ndx, c3ndx;
int i;
gettimeofday(&now, NULL);
mypid = getpid();
/* Initialize the state */
memset(nsid, 0, sizeof(*nsid));
nsid_hash(&now, sizeof now);
nsid_hash(&mypid, sizeof mypid);
/*
* Select our random number generators and initial seed.
* We could really use more random bits at this point,
* but we'll try to make a silk purse out of a sows ear ...
*/
/* generator 1 */
a1ndx = ((isc_uint32_t) NSID_MULT_TABLE_SIZE *
(nsid_hash_state & 0xFFFF)) >> 16;
nsid->nsid_a1 = nsid_multiplier_table[a1ndx];
c1ndx = (nsid_hash_state >> 9) & 0x7FFF;
nsid->nsid_c1 = 2 * c1ndx + 1;
/* generator 2, distinct from 1 */
a2ndx = ((isc_uint32_t) (NSID_MULT_TABLE_SIZE - 1) *
((nsid_hash_state >> 10) & 0xFFFF)) >> 16;
if (a2ndx >= a1ndx)
a2ndx++;
nsid->nsid_a2 = nsid_multiplier_table[a2ndx];
c2ndx = nsid_hash_state % 32767;
if (c2ndx >= c1ndx)
c2ndx++;
nsid->nsid_c2 = 2*c2ndx + 1;
/* generator 3, distinct from 1 and 2 */
a3ndx = ((isc_uint32_t) (NSID_MULT_TABLE_SIZE - 2) *
((nsid_hash_state >> 20) & 0xFFFF)) >> 16;
if (a3ndx >= a1ndx || a3ndx >= a2ndx)
a3ndx++;
if (a3ndx >= a1ndx && a3ndx >= a2ndx)
a3ndx++;
nsid->nsid_a3 = nsid_multiplier_table[a3ndx];
c3ndx = nsid_hash_state % 32766;
if (c3ndx >= c1ndx || c3ndx >= c2ndx)
c3ndx++;
if (c3ndx >= c1ndx && c3ndx >= c2ndx)
c3ndx++;
nsid->nsid_c3 = 2*c3ndx + 1;
nsid->nsid_state =
((nsid_hash_state >> 16) ^ (nsid_hash_state)) & 0xFFFF;
nsid->nsid_usepool = usepool;
if (nsid->nsid_usepool) {
nsid->nsid_pool = isc_mem_get(mctx, 0x10000 * sizeof(u_int16_t));
if (nsid->nsid_pool == NULL)
return (ISC_R_NOMEMORY);
for (i = 0; ; i++) {
nsid->nsid_pool[i] = nsid->nsid_state;
nsid->nsid_state =
(((u_long) nsid->nsid_a1 * nsid->nsid_state) +
nsid->nsid_c1) & 0xFFFF;
if (i == 0xFFFF)
break;
}
} else {
nsid->nsid_vtable = isc_mem_get(mctx, NSID_SHUFFLE_TABLE_SIZE *
(sizeof(isc_uint16_t)) );
if (nsid->nsid_vtable == NULL)
return (ISC_R_NOMEMORY);
for (i = 0; i < NSID_SHUFFLE_TABLE_SIZE; i++) {
nsid->nsid_vtable[i] = nsid->nsid_state;
nsid->nsid_state =
(((isc_uint32_t) nsid->nsid_a1 * nsid->nsid_state) +
nsid->nsid_c1) & 0xFFFF;
}
nsid->nsid_state2 = nsid->nsid_state;
}
return (ISC_R_SUCCESS);
}
static void
nsid_destroy(isc_mem_t *mctx, dns_nsid_t *nsid) {
if (nsid->nsid_usepool)
isc_mem_put(mctx, nsid->nsid_pool,
0x10000 * sizeof(isc_uint16_t));
else
isc_mem_put(mctx, nsid->nsid_vtable,
NSID_SHUFFLE_TABLE_SIZE * (sizeof(isc_uint16_t)) );
memset(nsid, 0, sizeof(*nsid));
}
void
dns_dispatch_hash(void *data, size_t len) {
nsid_hash(data, len);
}

9
lib/dns/include/dns/dispatch.h
View File

@ -15,7 +15,7 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: dispatch.h,v 1.55 2007/06/18 23:47:42 tbox Exp $ */
/* $Id: dispatch.h,v 1.56 2007/06/26 02:52:15 marka Exp $ */
#ifndef DNS_DISPATCH_H
#define DNS_DISPATCH_H 1
@ -445,6 +445,13 @@ dns_dispatch_importrecv(dns_dispatch_t *disp, isc_event_t *event);
* event != NULL
*/
void
dns_dispatch_hash(void *data, size_t len);
/*%<
* Feed 'data' to the dispatch query id generator where 'len' is the size
* of 'data'.
*/
ISC_LANG_ENDDECLS
#endif /* DNS_DISPATCH_H */