Commit fae42a57 authored by Natanael Copa's avatar Natanael Copa

main/strongswan: backport security fix (CVE-2018-16151, CVE-2018-16152)

fixes #9487
parent 526e4526
......@@ -24,6 +24,7 @@ source="http://download.strongswan.org/$pkgname-$_pkgver.tar.bz2
2001-support-gre-key-in-ikev1.patch
libressl.patch
CVE-2017-11185.patch
CVE-2018-16151-CVE-2018-16152.patch
strongswan.initd
charon.initd"
......@@ -31,6 +32,9 @@ source="http://download.strongswan.org/$pkgname-$_pkgver.tar.bz2
_builddir="$srcdir/$pkgname-$_pkgver"
# secfixes:
# 5.5.3-r2:
# - CVE-2018-16151
# - CVE-2018-16152
# 5.5.3-r1:
# - CVE-2017-11185
# 5.5.3-r0:
......@@ -129,5 +133,6 @@ d92ec44ac03c3eabe7583c01b15c66c9286681f42cf1d6ced3e1096c27c174014e14112610d2e12c
1544a409ad08f46a5dffbe3b4e8cf0e973c58140bf225f7c4e9b29be7fe6178f63d73730d1b2f7a755ed0d5dc09ee9fa0a08ac35761b01c5914d9bde1044ce7a 2001-support-gre-key-in-ikev1.patch
8cc4e28a07c4f206d7838a20cd1fdab7cd82bc19a3916ed65f1c5acf6acecd7ea54f582f7b2f164aded96e49fdc2db5ace70f426a93fcc08f29d658c79069ad4 libressl.patch
276bcbd0cd3c550ddd4b3f5dfbcb490bb1e50ec8ed97789944409e3c05232903b99332c653cec9c9cf46eab445fd67113d1babef32156b1a5c77a68d2b83260b CVE-2017-11185.patch
db64485fc0679a7fe32f3a69ae52e9e29abb6988ec900f07c350a61663321f7a5ffdfcb6c3371feb24923599a07d5a50bfbe1a72266666bf0a49a77631f92076 CVE-2018-16151-CVE-2018-16152.patch
8b61e3ffbb39b837733e602ec329e626dc519bf7308d3d4192b497d18f38176789d23ef5afec51f8463ee1ddaf4d74546b965c03184132e217cbc27017e886c9 strongswan.initd
1c44c801f66305c0331f76e580c0d60f1b7d5cd3cc371be55826b06c3899f542664628a912a7fb48626e34d864f72ca5dcd34b2f0d507c4f19c510d0047054c1 charon.initd"
From ade8c9c4b73ec43cf43b9c4cd9af6aac5e6f7f9d Mon Sep 17 00:00:00 2001
From: Tobias Brunner <tobias@strongswan.org>
Date: Tue, 28 Aug 2018 11:26:24 +0200
Subject: [PATCH] gmp: Don't parse PKCS1 v1.5 RSA signatures to verify them
Instead we generate the expected signature encoding and compare it to the
decrypted value.
Due to the lenient nature of the previous parsing code (minimum padding
length was not enforced, the algorithmIdentifier/OID parser accepts arbitrary
data after OIDs and in the parameters field etc.) it was susceptible to
Daniel Bleichenbacher's low-exponent attack (from 2006!), which allowed
forging signatures for keys that use low public exponents (i.e. e=3).
Since the public exponent is usually set to 0x10001 (65537) since quite a
while, the flaws in the previous code should not have had that much of a
practical impact in recent years.
Fixes: CVE-2018-16151, CVE-2018-16152
---
.../plugins/gmp/gmp_rsa_private_key.c | 66 +++++----
src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c | 158 ++-------------------
2 files changed, 53 insertions(+), 171 deletions(-)
diff --git a/src/libstrongswan/plugins/gmp/gmp_rsa_private_key.c b/src/libstrongswan/plugins/gmp/gmp_rsa_private_key.c
index 21b420866e2f..025f61a9fa21 100644
--- a/src/libstrongswan/plugins/gmp/gmp_rsa_private_key.c
+++ b/src/libstrongswan/plugins/gmp/gmp_rsa_private_key.c
@@ -262,14 +262,15 @@ static chunk_t rsasp1(private_gmp_rsa_private_key_t *this, chunk_t data)
}
/**
- * Build a signature using the PKCS#1 EMSA scheme
+ * Hashes the data and builds the plaintext signature value with EMSA
+ * PKCS#1 v1.5 padding.
+ *
+ * Allocates the signature data.
*/
-static bool build_emsa_pkcs1_signature(private_gmp_rsa_private_key_t *this,
- hash_algorithm_t hash_algorithm,
- chunk_t data, chunk_t *signature)
+bool gmp_emsa_pkcs1_signature_data(hash_algorithm_t hash_algorithm,
+ chunk_t data, size_t keylen, chunk_t *em)
{
chunk_t digestInfo = chunk_empty;
- chunk_t em;
if (hash_algorithm != HASH_UNKNOWN)
{
@@ -293,43 +294,56 @@ static bool build_emsa_pkcs1_signature(private_gmp_rsa_private_key_t *this,
/* build DER-encoded digestInfo */
digestInfo = asn1_wrap(ASN1_SEQUENCE, "mm",
asn1_algorithmIdentifier(hash_oid),
- asn1_simple_object(ASN1_OCTET_STRING, hash)
- );
- chunk_free(&hash);
+ asn1_wrap(ASN1_OCTET_STRING, "m", hash));
+
data = digestInfo;
}
- if (data.len > this->k - 3)
+ if (data.len > keylen - 11)
{
- free(digestInfo.ptr);
- DBG1(DBG_LIB, "unable to sign %d bytes using a %dbit key", data.len,
- mpz_sizeinbase(this->n, 2));
+ chunk_free(&digestInfo);
+ DBG1(DBG_LIB, "signature value of %zu bytes is too long for key of "
+ "%zu bytes", data.len, keylen);
return FALSE;
}
- /* build chunk to rsa-decrypt:
- * EM = 0x00 || 0x01 || PS || 0x00 || T.
- * PS = 0xFF padding, with length to fill em
+ /* EM = 0x00 || 0x01 || PS || 0x00 || T.
+ * PS = 0xFF padding, with length to fill em (at least 8 bytes)
* T = encoded_hash
*/
- em.len = this->k;
- em.ptr = malloc(em.len);
+ *em = chunk_alloc(keylen);
/* fill em with padding */
- memset(em.ptr, 0xFF, em.len);
+ memset(em->ptr, 0xFF, em->len);
/* set magic bytes */
- *(em.ptr) = 0x00;
- *(em.ptr+1) = 0x01;
- *(em.ptr + em.len - data.len - 1) = 0x00;
- /* set DER-encoded hash */
- memcpy(em.ptr + em.len - data.len, data.ptr, data.len);
+ *(em->ptr) = 0x00;
+ *(em->ptr+1) = 0x01;
+ *(em->ptr + em->len - data.len - 1) = 0x00;
+ /* set encoded hash */
+ memcpy(em->ptr + em->len - data.len, data.ptr, data.len);
+
+ chunk_clear(&digestInfo);
+ return TRUE;
+}
+
+/**
+ * Build a signature using the PKCS#1 EMSA scheme
+ */
+static bool build_emsa_pkcs1_signature(private_gmp_rsa_private_key_t *this,
+ hash_algorithm_t hash_algorithm,
+ chunk_t data, chunk_t *signature)
+{
+ chunk_t em;
+
+ if (!gmp_emsa_pkcs1_signature_data(hash_algorithm, data, this->k, &em))
+ {
+ return FALSE;
+ }
/* build signature */
*signature = rsasp1(this, em);
- free(digestInfo.ptr);
- free(em.ptr);
-
+ chunk_free(&em);
return TRUE;
}
diff --git a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
index 065c88903344..f27b24c6f319 100644
--- a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
+++ b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
@@ -68,7 +68,9 @@ struct private_gmp_rsa_public_key_t {
/**
* Shared functions defined in gmp_rsa_private_key.c
*/
-extern chunk_t gmp_mpz_to_chunk(const mpz_t value);
+chunk_t gmp_mpz_to_chunk(const mpz_t value);
+bool gmp_emsa_pkcs1_signature_data(hash_algorithm_t hash_algorithm,
+ chunk_t data, size_t keylen, chunk_t *em);
/**
* RSAEP algorithm specified in PKCS#1.
@@ -113,26 +115,13 @@ static chunk_t rsavp1(private_gmp_rsa_public_key_t *this, chunk_t data)
}
/**
- * ASN.1 definition of digestInfo
- */
-static const asn1Object_t digestInfoObjects[] = {
- { 0, "digestInfo", ASN1_SEQUENCE, ASN1_OBJ }, /* 0 */
- { 1, "digestAlgorithm", ASN1_EOC, ASN1_RAW }, /* 1 */
- { 1, "digest", ASN1_OCTET_STRING, ASN1_BODY }, /* 2 */
- { 0, "exit", ASN1_EOC, ASN1_EXIT }
-};
-#define DIGEST_INFO 0
-#define DIGEST_INFO_ALGORITHM 1
-#define DIGEST_INFO_DIGEST 2
-
-/**
- * Verification of an EMPSA PKCS1 signature described in PKCS#1
+ * Verification of an EMSA PKCS1 signature described in PKCS#1
*/
static bool verify_emsa_pkcs1_signature(private_gmp_rsa_public_key_t *this,
hash_algorithm_t algorithm,
chunk_t data, chunk_t signature)
{
- chunk_t em_ori, em;
+ chunk_t em_expected, em;
bool success = FALSE;
/* remove any preceding 0-bytes from signature */
@@ -146,140 +135,19 @@ static bool verify_emsa_pkcs1_signature(private_gmp_rsa_public_key_t *this,
return FALSE;
}
- /* unpack signature */
- em_ori = em = rsavp1(this, signature);
-
- /* result should look like this:
- * EM = 0x00 || 0x01 || PS || 0x00 || T.
- * PS = 0xFF padding, with length to fill em
- * T = oid || hash
- */
-
- /* check magic bytes */
- if (em.len < 2 || *(em.ptr) != 0x00 || *(em.ptr+1) != 0x01)
- {
- goto end;
- }
- em = chunk_skip(em, 2);
-
- /* find magic 0x00 */
- while (em.len > 0)
- {
- if (*em.ptr == 0x00)
- {
- /* found magic byte, stop */
- em = chunk_skip(em, 1);
- break;
- }
- else if (*em.ptr != 0xFF)
- {
- /* bad padding, decryption failed ?!*/
- goto end;
- }
- em = chunk_skip(em, 1);
- }
-
- if (em.len == 0)
+ /* generate expected signature value */
+ if (!gmp_emsa_pkcs1_signature_data(algorithm, data, this->k, &em_expected))
{
- /* no digestInfo found */
- goto end;
- }
-
- if (algorithm == HASH_UNKNOWN)
- { /* IKEv1 signatures without digestInfo */
- if (em.len != data.len)
- {
- DBG1(DBG_LIB, "hash size in signature is %u bytes instead of"
- " %u bytes", em.len, data.len);
- goto end;
- }
- success = memeq_const(em.ptr, data.ptr, data.len);
+ return FALSE;
}
- else
- { /* IKEv2 and X.509 certificate signatures */
- asn1_parser_t *parser;
- chunk_t object;
- int objectID;
- hash_algorithm_t hash_algorithm = HASH_UNKNOWN;
- DBG2(DBG_LIB, "signature verification:");
- parser = asn1_parser_create(digestInfoObjects, em);
-
- while (parser->iterate(parser, &objectID, &object))
- {
- switch (objectID)
- {
- case DIGEST_INFO:
- {
- if (em.len > object.len)
- {
- DBG1(DBG_LIB, "digestInfo field in signature is"
- " followed by %u surplus bytes",
- em.len - object.len);
- goto end_parser;
- }
- break;
- }
- case DIGEST_INFO_ALGORITHM:
- {
- int hash_oid = asn1_parse_algorithmIdentifier(object,
- parser->get_level(parser)+1, NULL);
-
- hash_algorithm = hasher_algorithm_from_oid(hash_oid);
- if (hash_algorithm == HASH_UNKNOWN || hash_algorithm != algorithm)
- {
- DBG1(DBG_LIB, "expected hash algorithm %N, but found"
- " %N (OID: %#B)", hash_algorithm_names, algorithm,
- hash_algorithm_names, hash_algorithm, &object);
- goto end_parser;
- }
- break;
- }
- case DIGEST_INFO_DIGEST:
- {
- chunk_t hash;
- hasher_t *hasher;
-
- hasher = lib->crypto->create_hasher(lib->crypto, hash_algorithm);
- if (hasher == NULL)
- {
- DBG1(DBG_LIB, "hash algorithm %N not supported",
- hash_algorithm_names, hash_algorithm);
- goto end_parser;
- }
-
- if (object.len != hasher->get_hash_size(hasher))
- {
- DBG1(DBG_LIB, "hash size in signature is %u bytes"
- " instead of %u bytes", object.len,
- hasher->get_hash_size(hasher));
- hasher->destroy(hasher);
- goto end_parser;
- }
-
- /* build our own hash and compare */
- if (!hasher->allocate_hash(hasher, data, &hash))
- {
- hasher->destroy(hasher);
- goto end_parser;
- }
- hasher->destroy(hasher);
- success = memeq_const(object.ptr, hash.ptr, hash.len);
- free(hash.ptr);
- break;
- }
- default:
- break;
- }
- }
+ /* unpack signature */
+ em = rsavp1(this, signature);
-end_parser:
- success &= parser->success(parser);
- parser->destroy(parser);
- }
+ success = chunk_equals_const(em_expected, em);
-end:
- free(em_ori.ptr);
+ chunk_free(&em_expected);
+ chunk_free(&em);
return success;
}
--
2.7.4
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