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[v9_9] address buffer accounting error

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4168.	[security]	A buffer accounting error could trigger an
			assertion failure when parsing certain malformed
			DNSSEC keys. (CVE-2015-5722) [RT #40212]

(cherry picked from commit ce9f893e21)
This commit is contained in:
Evan Hunt 2015-08-07 13:22:40 -07:00
parent c0fef5552a
commit 0d83784a75
11 changed files with 110 additions and 66 deletions
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4
CHANGES
View file

@ -1,3 +1,7 @@
4168. [security] A buffer accounting error could trigger an
assertion failure when parsing certain malformed
DNSSEC keys. (CVE-2015-5722) [RT #40212]
--- 9.9.8b1 released ---
4165. [security] A failure to reset a value to NULL in tkey.c could

14
README
View file

@ -55,9 +55,11 @@ BIND 9.9.8
BIND 9.9.8 is a maintenance release and addresses bugs
found in BIND 9.9.7 and earlier, as well as the security
flaws described in CVE-2015-4620 and CVE-2015-5477. It also
makes the following new features available via a compile
time option:
flaws described in CVE-2015-4620, CVE-2015-5477, and
CVE-2015-5722.
It also makes the following new features available via a
compile-time option:
- New "fetchlimit" quotas are now available for the use of
recursive resolvers that are are under high query load for
@ -73,11 +75,11 @@ BIND 9.9.8
+ "fetches-per-zone" limits the number of simultaneous queries
that can be sent for names within a single domain. (Note:
Unlike "fetches-per-server", this value is not self-tuning.)
+ New stats counters have been added to count
+ New stats counters have been added to count
queries spilled due to these quotas.
NOTE: These options are NOT built in by default; use
"configure --enable-fetchlimit" to enable them.
NOTE: These options are NOT built in by default; use
"configure --enable-fetchlimit" to enable them.
BIND 9.9.7

12
doc/arm/notes.xml
View file

@ -38,10 +38,20 @@
<sect2 id="relnotes_security">
<title>Security Fixes</title>
<itemizedlist>
<listitem>
<para>
A buffer accounting error could trigger an assertion failure
when parsing certain malformed DNSSEC keys.
</para>
<para>
This flaw was discovered by Hanno B&ouml;ck of the Fuzzing
Project, and is disclosed in CVE-2015-5722. [RT #40212]
</para>
</listitem>
<listitem>
<para>
A specially crafted query could trigger an assertion failure
in message.c
in message.c.
</para>
<para>
This flaw was discovered by Jonathan Foote, and is disclosed

30
lib/dns/hmac_link.c
View file

@ -76,7 +76,7 @@ hmacmd5_createctx(dst_key_t *key, dst_context_t *dctx) {
hmacmd5ctx = isc_mem_get(dctx->mctx, sizeof(isc_hmacmd5_t));
if (hmacmd5ctx == NULL)
return (ISC_R_NOMEMORY);
isc_hmacmd5_init(hmacmd5ctx, hkey->key, ISC_SHA1_BLOCK_LENGTH);
isc_hmacmd5_init(hmacmd5ctx, hkey->key, ISC_MD5_BLOCK_LENGTH);
dctx->ctxdata.hmacmd5ctx = hmacmd5ctx;
return (ISC_R_SUCCESS);
}
@ -139,7 +139,7 @@ hmacmd5_compare(const dst_key_t *key1, const dst_key_t *key2) {
else if (hkey1 == NULL || hkey2 == NULL)
return (ISC_FALSE);
if (isc_safe_memcmp(hkey1->key, hkey2->key, ISC_SHA1_BLOCK_LENGTH))
if (isc_safe_memcmp(hkey1->key, hkey2->key, ISC_MD5_BLOCK_LENGTH))
return (ISC_TRUE);
else
return (ISC_FALSE);
@ -150,17 +150,17 @@ hmacmd5_generate(dst_key_t *key, int pseudorandom_ok, void (*callback)(int)) {
isc_buffer_t b;
isc_result_t ret;
unsigned int bytes;
unsigned char data[ISC_SHA1_BLOCK_LENGTH];
unsigned char data[ISC_MD5_BLOCK_LENGTH];
UNUSED(callback);
bytes = (key->key_size + 7) / 8;
if (bytes > ISC_SHA1_BLOCK_LENGTH) {
bytes = ISC_SHA1_BLOCK_LENGTH;
key->key_size = ISC_SHA1_BLOCK_LENGTH * 8;
if (bytes > ISC_MD5_BLOCK_LENGTH) {
bytes = ISC_MD5_BLOCK_LENGTH;
key->key_size = ISC_MD5_BLOCK_LENGTH * 8;
}
memset(data, 0, ISC_SHA1_BLOCK_LENGTH);
memset(data, 0, ISC_MD5_BLOCK_LENGTH);
ret = dst__entropy_getdata(data, bytes, ISC_TF(pseudorandom_ok != 0));
if (ret != ISC_R_SUCCESS)
@ -169,7 +169,7 @@ hmacmd5_generate(dst_key_t *key, int pseudorandom_ok, void (*callback)(int)) {
isc_buffer_init(&b, data, bytes);
isc_buffer_add(&b, bytes);
ret = hmacmd5_fromdns(key, &b);
memset(data, 0, ISC_SHA1_BLOCK_LENGTH);
memset(data, 0, ISC_MD5_BLOCK_LENGTH);
return (ret);
}
@ -223,7 +223,7 @@ hmacmd5_fromdns(dst_key_t *key, isc_buffer_t *data) {
memset(hkey->key, 0, sizeof(hkey->key));
if (r.length > ISC_SHA1_BLOCK_LENGTH) {
if (r.length > ISC_MD5_BLOCK_LENGTH) {
isc_md5_init(&md5ctx);
isc_md5_update(&md5ctx, r.base, r.length);
isc_md5_final(&md5ctx, hkey->key);
@ -236,6 +236,8 @@ hmacmd5_fromdns(dst_key_t *key, isc_buffer_t *data) {
key->key_size = keylen * 8;
key->keydata.hmacmd5 = hkey;
isc_buffer_forward(data, r.length);
return (ISC_R_SUCCESS);
}
@ -512,6 +514,8 @@ hmacsha1_fromdns(dst_key_t *key, isc_buffer_t *data) {
key->key_size = keylen * 8;
key->keydata.hmacsha1 = hkey;
isc_buffer_forward(data, r.length);
return (ISC_R_SUCCESS);
}
@ -790,6 +794,8 @@ hmacsha224_fromdns(dst_key_t *key, isc_buffer_t *data) {
key->key_size = keylen * 8;
key->keydata.hmacsha224 = hkey;
isc_buffer_forward(data, r.length);
return (ISC_R_SUCCESS);
}
@ -1068,6 +1074,8 @@ hmacsha256_fromdns(dst_key_t *key, isc_buffer_t *data) {
key->key_size = keylen * 8;
key->keydata.hmacsha256 = hkey;
isc_buffer_forward(data, r.length);
return (ISC_R_SUCCESS);
}
@ -1346,6 +1354,8 @@ hmacsha384_fromdns(dst_key_t *key, isc_buffer_t *data) {
key->key_size = keylen * 8;
key->keydata.hmacsha384 = hkey;
isc_buffer_forward(data, r.length);
return (ISC_R_SUCCESS);
}
@ -1624,6 +1634,8 @@ hmacsha512_fromdns(dst_key_t *key, isc_buffer_t *data) {
key->key_size = keylen * 8;
key->keydata.hmacsha512 = hkey;
isc_buffer_forward(data, r.length);
return (ISC_R_SUCCESS);
}

1
lib/dns/include/dst/dst.h
View file

@ -69,6 +69,7 @@ typedef struct dst_context dst_context_t;
#define DST_ALG_HMACSHA256 163 /* XXXMPA */
#define DST_ALG_HMACSHA384 164 /* XXXMPA */
#define DST_ALG_HMACSHA512 165 /* XXXMPA */
#define DST_ALG_INDIRECT 252
#define DST_ALG_PRIVATE 254
#define DST_ALG_EXPAND 255
#define DST_MAX_ALGS 255

9
lib/dns/ncache.c
View file

@ -612,13 +612,11 @@ dns_ncache_getsigrdataset(dns_rdataset_t *ncacherdataset, dns_name_t *name,
dns_name_fromregion(&tname, &remaining);
INSIST(remaining.length >= tname.length);
isc_buffer_forward(&source, tname.length);
remaining.length -= tname.length;
remaining.base += tname.length;
isc_region_consume(&remaining, tname.length);
INSIST(remaining.length >= 2);
type = isc_buffer_getuint16(&source);
remaining.length -= 2;
remaining.base += 2;
isc_region_consume(&remaining, 2);
if (type != dns_rdatatype_rrsig ||
!dns_name_equal(&tname, name)) {
@ -630,8 +628,7 @@ dns_ncache_getsigrdataset(dns_rdataset_t *ncacherdataset, dns_name_t *name,
INSIST(remaining.length >= 1);
trust = isc_buffer_getuint8(&source);
INSIST(trust <= dns_trust_ultimate);
remaining.length -= 1;
remaining.base += 1;
isc_region_consume(&remaining, 1);
raw = remaining.base;
count = raw[0] * 256 + raw[1];

35
lib/dns/openssldh_link.c
View file

@ -277,8 +277,10 @@ openssldh_destroy(dst_key_t *key) {
static void
uint16_toregion(isc_uint16_t val, isc_region_t *region) {
*region->base++ = (val & 0xff00) >> 8;
*region->base++ = (val & 0x00ff);
*region->base = (val & 0xff00) >> 8;
isc_region_consume(region, 1);
*region->base = (val & 0x00ff);
isc_region_consume(region, 1);
}
static isc_uint16_t
@ -289,7 +291,8 @@ uint16_fromregion(isc_region_t *region) {
val = ((unsigned int)(cp[0])) << 8;
val |= ((unsigned int)(cp[1]));
region->base += 2;
isc_region_consume(region, 2);
return (val);
}
@ -330,16 +333,16 @@ openssldh_todns(const dst_key_t *key, isc_buffer_t *data) {
}
else
BN_bn2bin(dh->p, r.base);
r.base += plen;
isc_region_consume(&r, plen);
uint16_toregion(glen, &r);
if (glen > 0)
BN_bn2bin(dh->g, r.base);
r.base += glen;
isc_region_consume(&r, glen);
uint16_toregion(publen, &r);
BN_bn2bin(dh->pub_key, r.base);
r.base += publen;
isc_region_consume(&r, publen);
isc_buffer_add(data, dnslen);
@ -380,10 +383,12 @@ openssldh_fromdns(dst_key_t *key, isc_buffer_t *data) {
return (DST_R_INVALIDPUBLICKEY);
}
if (plen == 1 || plen == 2) {
if (plen == 1)
special = *r.base++;
else
if (plen == 1) {
special = *r.base;
isc_region_consume(&r, 1);
} else {
special = uint16_fromregion(&r);
}
switch (special) {
case 1:
dh->p = bn768;
@ -398,10 +403,9 @@ openssldh_fromdns(dst_key_t *key, isc_buffer_t *data) {
DH_free(dh);
return (DST_R_INVALIDPUBLICKEY);
}
}
else {
} else {
dh->p = BN_bin2bn(r.base, plen, NULL);
r.base += plen;
isc_region_consume(&r, plen);
}
/*
@ -432,15 +436,14 @@ openssldh_fromdns(dst_key_t *key, isc_buffer_t *data) {
return (DST_R_INVALIDPUBLICKEY);
}
}
}
else {
} else {
if (glen == 0) {
DH_free(dh);
return (DST_R_INVALIDPUBLICKEY);
}
dh->g = BN_bin2bn(r.base, glen, NULL);
}
r.base += glen;
isc_region_consume(&r, glen);
if (r.length < 2) {
DH_free(dh);
@ -452,7 +455,7 @@ openssldh_fromdns(dst_key_t *key, isc_buffer_t *data) {
return (DST_R_INVALIDPUBLICKEY);
}
dh->pub_key = BN_bin2bn(r.base, publen, NULL);
r.base += publen;
isc_region_consume(&r, publen);
key->key_size = BN_num_bits(dh->p);

40
lib/dns/openssldsa_link.c
View file

@ -29,8 +29,6 @@
* IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id$ */
#ifdef OPENSSL
#ifndef USE_EVP
#define USE_EVP 1
@ -137,6 +135,7 @@ openssldsa_sign(dst_context_t *dctx, isc_buffer_t *sig) {
DSA *dsa = key->keydata.dsa;
isc_region_t r;
DSA_SIG *dsasig;
unsigned int klen;
#if USE_EVP
EVP_MD_CTX *evp_md_ctx = dctx->ctxdata.evp_md_ctx;
EVP_PKEY *pkey;
@ -188,6 +187,7 @@ openssldsa_sign(dst_context_t *dctx, isc_buffer_t *sig) {
ISC_R_FAILURE));
}
free(sigbuf);
#elif 0
/* Only use EVP for the Digest */
if (!EVP_DigestFinal_ex(evp_md_ctx, digest, &siglen)) {
@ -209,11 +209,17 @@ openssldsa_sign(dst_context_t *dctx, isc_buffer_t *sig) {
"DSA_do_sign",
DST_R_SIGNFAILURE));
#endif
*r.base++ = (key->key_size - 512)/64;
klen = (key->key_size - 512)/64;
if (klen > 255)
return (ISC_R_FAILURE);
*r.base = klen;
isc_region_consume(&r, 1);
BN_bn2bin_fixed(dsasig->r, r.base, ISC_SHA1_DIGESTLENGTH);
r.base += ISC_SHA1_DIGESTLENGTH;
isc_region_consume(&r, ISC_SHA1_DIGESTLENGTH);
BN_bn2bin_fixed(dsasig->s, r.base, ISC_SHA1_DIGESTLENGTH);
r.base += ISC_SHA1_DIGESTLENGTH;
isc_region_consume(&r, ISC_SHA1_DIGESTLENGTH);
DSA_SIG_free(dsasig);
isc_buffer_add(sig, ISC_SHA1_DIGESTLENGTH * 2 + 1);
@ -457,15 +463,16 @@ openssldsa_todns(const dst_key_t *key, isc_buffer_t *data) {
if (r.length < (unsigned int) dnslen)
return (ISC_R_NOSPACE);
*r.base++ = t;
*r.base = t;
isc_region_consume(&r, 1);
BN_bn2bin_fixed(dsa->q, r.base, ISC_SHA1_DIGESTLENGTH);
r.base += ISC_SHA1_DIGESTLENGTH;
isc_region_consume(&r, ISC_SHA1_DIGESTLENGTH);
BN_bn2bin_fixed(dsa->p, r.base, key->key_size/8);
r.base += p_bytes;
isc_region_consume(&r, p_bytes);
BN_bn2bin_fixed(dsa->g, r.base, key->key_size/8);
r.base += p_bytes;
isc_region_consume(&r, p_bytes);
BN_bn2bin_fixed(dsa->pub_key, r.base, key->key_size/8);
r.base += p_bytes;
isc_region_consume(&r, p_bytes);
isc_buffer_add(data, dnslen);
@ -490,29 +497,30 @@ openssldsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
return (ISC_R_NOMEMORY);
dsa->flags &= ~DSA_FLAG_CACHE_MONT_P;
t = (unsigned int) *r.base++;
t = (unsigned int) *r.base;
isc_region_consume(&r, 1);
if (t > 8) {
DSA_free(dsa);
return (DST_R_INVALIDPUBLICKEY);
}
p_bytes = 64 + 8 * t;
if (r.length < 1 + ISC_SHA1_DIGESTLENGTH + 3 * p_bytes) {
if (r.length < ISC_SHA1_DIGESTLENGTH + 3 * p_bytes) {
DSA_free(dsa);
return (DST_R_INVALIDPUBLICKEY);
}
dsa->q = BN_bin2bn(r.base, ISC_SHA1_DIGESTLENGTH, NULL);
r.base += ISC_SHA1_DIGESTLENGTH;
isc_region_consume(&r, ISC_SHA1_DIGESTLENGTH);
dsa->p = BN_bin2bn(r.base, p_bytes, NULL);
r.base += p_bytes;
isc_region_consume(&r, p_bytes);
dsa->g = BN_bin2bn(r.base, p_bytes, NULL);
r.base += p_bytes;
isc_region_consume(&r, p_bytes);
dsa->pub_key = BN_bin2bn(r.base, p_bytes, NULL);
r.base += p_bytes;
isc_region_consume(&r, p_bytes);
key->key_size = p_bytes * 8;

6
lib/dns/opensslecdsa_link.c
View file

@ -14,8 +14,6 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id$ */
#include <config.h>
#ifdef HAVE_OPENSSL_ECDSA
@ -159,9 +157,9 @@ opensslecdsa_sign(dst_context_t *dctx, isc_buffer_t *sig) {
"ECDSA_do_sign",
DST_R_SIGNFAILURE));
BN_bn2bin_fixed(ecdsasig->r, r.base, siglen / 2);
r.base += siglen / 2;
isc_region_consume(&r, siglen / 2);
BN_bn2bin_fixed(ecdsasig->s, r.base, siglen / 2);
r.base += siglen / 2;
isc_region_consume(&r, siglen / 2);
ECDSA_SIG_free(ecdsasig);
isc_buffer_add(sig, siglen);
ret = ISC_R_SUCCESS;

18
lib/dns/opensslrsa_link.c
View file

@ -972,6 +972,7 @@ opensslrsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
RSA *rsa;
isc_region_t r;
unsigned int e_bytes;
unsigned int length;
#if USE_EVP
EVP_PKEY *pkey;
#endif
@ -979,6 +980,7 @@ opensslrsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
isc_buffer_remainingregion(data, &r);
if (r.length == 0)
return (ISC_R_SUCCESS);
length = r.length;
rsa = RSA_new();
if (rsa == NULL)
@ -989,17 +991,18 @@ opensslrsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
RSA_free(rsa);
return (DST_R_INVALIDPUBLICKEY);
}
e_bytes = *r.base++;
r.length--;
e_bytes = *r.base;
isc_region_consume(&r, 1);
if (e_bytes == 0) {
if (r.length < 2) {
RSA_free(rsa);
return (DST_R_INVALIDPUBLICKEY);
}
e_bytes = ((*r.base++) << 8);
e_bytes += *r.base++;
r.length -= 2;
e_bytes = (*r.base) << 8;
isc_region_consume(&r, 1);
e_bytes += *r.base;
isc_region_consume(&r, 1);
}
if (r.length < e_bytes) {
@ -1007,14 +1010,13 @@ opensslrsa_fromdns(dst_key_t *key, isc_buffer_t *data) {
return (DST_R_INVALIDPUBLICKEY);
}
rsa->e = BN_bin2bn(r.base, e_bytes, NULL);
r.base += e_bytes;
r.length -= e_bytes;
isc_region_consume(&r, e_bytes);
rsa->n = BN_bin2bn(r.base, r.length, NULL);
key->key_size = BN_num_bits(rsa->n);
isc_buffer_forward(data, r.length);
isc_buffer_forward(data, length);
#if USE_EVP
pkey = EVP_PKEY_new();

7
lib/dns/resolver.c
View file

@ -9585,6 +9585,12 @@ dns_resolver_algorithm_supported(dns_resolver_t *resolver, dns_name_t *name,
REQUIRE(VALID_RESOLVER(resolver));
/*
* DH is unsupported for DNSKEYs, see RFC 4034 sec. A.1.
*/
if ((alg == DST_ALG_DH) || (alg == DST_ALG_INDIRECT))
return (ISC_FALSE);
#if USE_ALGLOCK
RWLOCK(&resolver->alglock, isc_rwlocktype_read);
#endif
@ -9604,6 +9610,7 @@ dns_resolver_algorithm_supported(dns_resolver_t *resolver, dns_name_t *name,
#endif
if (found)
return (ISC_FALSE);
return (dst_algorithm_supported(alg));
}