check hash algorithms used in signatures

src/charon/config/credentials/local_credential_store.c

@@ -832,7 +832,7 @@ static status_t verify_signature(private_local_credential_store_t *this,
 				}
 				*issuer_p = issuer;
 			}
-			sig_status = public_key->verify_emsa_pkcs1_signature(public_key, hash, signature);
+			sig_status = public_key->verify_emsa_pkcs1_signature(public_key, HASH_UNKNOWN, hash, signature);
 			if (sig_status == SUCCESS)
 			{
 				DBG2(DBG_CFG, "candidate peer certificate has a matching RSA public key");

src/libstrongswan/crypto/crl.c

@@ -304,6 +304,11 @@ bool parse_x509crl(chunk_t blob, u_int level0, private_crl_t *crl)
 				break;
 			case CRL_OBJ_ALGORITHM:
 				crl->algorithm = parse_algorithmIdentifier(object, level, NULL);
+				if (crl->algorithm != crl->sigAlg)
+				{
+					DBG1("  signature algorithms do not agree");
+					return FALSE;
+				}
 				break;
 			case CRL_OBJ_SIGNATURE:
 				crl->signature = object;
@@ -374,7 +379,14 @@ static bool is_newer(const private_crl_t *this, const private_crl_t *other)
  */
 static bool verify(const private_crl_t *this, const rsa_public_key_t *signer)
 {
-	return signer->verify_emsa_pkcs1_signature(signer, this->tbsCertList, this->signature) == SUCCESS;
+	hash_algorithm_t algorithm = hasher_algorithm_from_oid(this->algorithm);
+
+	if (algorithm == HASH_UNKNOWN)
+	{
+		DBG1("  unknown signature algorithm");
+		return FALSE;
+	}
+	return signer->verify_emsa_pkcs1_signature(signer, algorithm, this->tbsCertList, this->signature) == SUCCESS;
 }
 
 /**

src/libstrongswan/crypto/hashers/hasher.c

@@ -24,12 +24,14 @@
 
 #include "hasher.h"
 
+#include <asn1/oid.h>
 #include <crypto/hashers/sha1_hasher.h>
 #include <crypto/hashers/sha2_hasher.h>
 #include <crypto/hashers/md5_hasher.h>
 
 
-ENUM(hash_algorithm_names, HASH_MD2, HASH_SHA512,
+ENUM(hash_algorithm_names, HASH_UNKNOWN, HASH_SHA512,
+	"HASH_UNKNOWN",
 	"HASH_MD2",
 	"HASH_MD5",
 	"HASH_SHA1",
@@ -63,3 +65,42 @@ hasher_t *hasher_create(hash_algorithm_t hash_algorithm)
 			return NULL;
 	}
 }
+
+/*
+ * Described in header.
+ */
+hash_algorithm_t hasher_algorithm_from_oid(int oid)
+{
+	hash_algorithm_t algorithm;
+
+	switch (oid)
+	{
+		case OID_MD2:
+		case OID_MD2_WITH_RSA:
+			algorithm = HASH_MD2;
+			break;
+		case OID_MD5:
+		case OID_MD5_WITH_RSA:
+			algorithm = HASH_MD5;
+			break;
+		case OID_SHA1:
+		case OID_SHA1_WITH_RSA:
+			algorithm = HASH_SHA1;
+			break;
+		case OID_SHA256:
+		case OID_SHA256_WITH_RSA:
+			algorithm = HASH_SHA256;
+			break;
+		case OID_SHA384:
+		case OID_SHA384_WITH_RSA:
+			algorithm = HASH_SHA384;
+			break;
+		case OID_SHA512:
+		case OID_SHA512_WITH_RSA:
+			algorithm = HASH_SHA512;
+			break;
+		default:
+			algorithm = HASH_UNKNOWN;
+	}
+	return algorithm;
+}

src/libstrongswan/crypto/hashers/hasher.h

@@ -42,17 +42,18 @@ typedef struct hasher_t hasher_t;
  * @ingroup hashers
  */
 enum hash_algorithm_t {
-	HASH_MD2 = 0,
+	HASH_UNKNOWN = 0,
+	HASH_MD2 =     1,
 	/** Implemented in class md5_hasher_t */
-	HASH_MD5 = 1,
+	HASH_MD5 =     2,
 	/** Implemented in class sha1_hasher_t */
-	HASH_SHA1 = 2,
+	HASH_SHA1 =    3,
 	/** Implemented in class sha2_hasher_t */
-	HASH_SHA256 = 3,
+	HASH_SHA256 =  4,
 	/** Implemented in class sha2_hasher_t */
-	HASH_SHA384 = 4,
+	HASH_SHA384 =  5,
 	/** Implemented in class sha2_hasher_t */
-	HASH_SHA512 = 5,
+	HASH_SHA512 =  6,
 };
 
 #define HASH_SIZE_MD2		16
@@ -68,7 +69,6 @@ enum hash_algorithm_t {
  */
 extern enum_name_t *hash_algorithm_names;
 
-
 /**
  * @brief Generic interface for all hash functions.
  * 
@@ -156,4 +156,16 @@ struct hasher_t {
  */
 hasher_t *hasher_create(hash_algorithm_t hash_algorithm);
 
+/**
+ * @brief Conversion of ASN.1 OID to hash algorithm.
+ * 
+ * @param oid				ASN.1 OID
+ * @return
+ * 							- hash algorithm
+ * 							- HASH_UNKNOWN if OID unsuported
+ * 
+ * @ingroup hashers
+ */
+hash_algorithm_t hasher_algorithm_from_oid(int oid);
+
 #endif /* HASHER_H_ */

src/libstrongswan/crypto/ocsp.c

@@ -614,6 +614,13 @@ static bool ocsp_valid_response(response_t *res, x509_t *ocsp_cert)
 	rsa_public_key_t *public_key;
 	time_t until = UNDEFINED_TIME;
 	err_t ugh;
+	hash_algorithm_t algorithm = hasher_algorithm_from_oid(res->algorithm);
+
+	if (algorithm == HASH_UNKNOWN)
+	{
+		DBG1("unknown signature algorithm");
+		return FALSE;
+	}
 
 	DBG2("verifying ocsp response signature:");
 	DBG2("signer:  '%D'", ocsp_cert->get_subject(ocsp_cert));
@@ -626,8 +633,8 @@ static bool ocsp_valid_response(response_t *res, x509_t *ocsp_cert)
 		return FALSE;
 	}
 	public_key = ocsp_cert->get_public_key(ocsp_cert);
-
+	
-	return public_key->verify_emsa_pkcs1_signature(public_key, res->tbs, res->signature) == SUCCESS;
+	return public_key->verify_emsa_pkcs1_signature(public_key, algorithm, res->tbs, res->signature) == SUCCESS;
 }
 
 /**

src/libstrongswan/crypto/rsa/rsa_public_key.c

@@ -33,70 +33,10 @@
 #include <asn1/asn1.h>
 #include <asn1/pem.h>
 
-/* 
- * For simplicity, we use these predefined values for hash algorithm OIDs 
- * These also contain the length of the appended hash  
- * These values are also  used in rsa_private_key.c.
- */
-
-const u_int8_t md2_oid[] = {
-	0x30,0x20,
-		 0x30,0x0c,
-			  0x06,0x08,
-				   0x2a,0x86,0x48,0x86,0xf7,0x0d,0x02,0x02,
-			  0x05,0x00,
-		 0x04,0x10
-};
-
-const u_int8_t md5_oid[] = {
-	0x30,0x20,
-		 0x30,0x0c,
-			  0x06,0x08,
-				   0x2a,0x86,0x48,0x86,0xf7,0x0d,0x02,0x05,
-			  0x05,0x00,
-		 0x04,0x10
-};
-
-const u_int8_t sha1_oid[] = {
-	0x30,0x21,
-		 0x30,0x09,
-			  0x06,0x05,
-				   0x2b,0x0e,0x03,0x02,0x1a,
-			  0x05,0x00,
-		 0x04,0x14
-};
-
-const u_int8_t sha256_oid[] = {
-	0x30,0x31,
-		 0x30,0x0d,
-			  0x06,0x09,
-				   0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x01,
-			  0x05,0x00,
-		 0x04,0x20
-};
-
-const u_int8_t sha384_oid[] = {
-	0x30,0x41,
-		 0x30,0x0d,
-			  0x06,0x09,
-				   0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x02,
-			  0x05,0x00,
-		 0x04,0x30
-};
-
-const u_int8_t sha512_oid[] = {
-	0x30,0x51,
-		 0x30,0x0d,
-			  0x06,0x09,
-				   0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x03,
-			  0x05,0x00,
-		 0x04,0x40
-};
-
 #define LARGEST_HASH_OID_SIZE sizeof(sha512_oid)
 
-/* ASN.1 definition public key */
+/* ASN.1 definition of RSApublicKey */
-static const asn1Object_t pubkey_objects[] = {
+static const asn1Object_t pubkeyObjects[] = {
 	{ 0, "RSAPublicKey",		ASN1_SEQUENCE,     ASN1_OBJ  }, /*  0 */
 	{ 1,   "modulus",			ASN1_INTEGER,      ASN1_BODY }, /*  1 */
 	{ 1,   "publicExponent",	ASN1_INTEGER,      ASN1_BODY }, /*  2 */
@@ -107,6 +47,17 @@ static const asn1Object_t pubkey_objects[] = {
 #define PUB_KEY_EXPONENT			2
 #define PUB_KEY_ROOF				3
 
+/* ASN.1 definition of digestInfo */
+static const asn1Object_t digestInfoObjects[] = {
+	{ 0, "digestInfo",			ASN1_SEQUENCE,		ASN1_NONE }, /*  0 */
+	{ 1,   "digestAlgorithm",	ASN1_EOC,			ASN1_RAW  }, /*  1 */
+	{ 1,   "digest",			ASN1_OCTET_STRING,	ASN1_BODY }, /*  2 */
+};
+
+#define DIGEST_INFO_ALGORITHM		1
+#define DIGEST_INFO_DIGEST			2
+#define DIGEST_INFO_ROOF			3
+
 typedef struct private_rsa_public_key_t private_rsa_public_key_t;
 
 /**
@@ -186,12 +137,11 @@ static chunk_t rsaep(const private_rsa_public_key_t *this, chunk_t data)
 /**
  * Implementation of rsa_public_key.verify_emsa_pkcs1_signature.
  */
-static status_t verify_emsa_pkcs1_signature(const private_rsa_public_key_t *this, chunk_t data, chunk_t signature)
+static status_t verify_emsa_pkcs1_signature(const private_rsa_public_key_t *this,
+											hash_algorithm_t algorithm,
+											chunk_t data, chunk_t signature)
 {
-	hasher_t *hasher = NULL;
+	chunk_t em_ori, em;
-	chunk_t hash;
-	chunk_t em;
-	u_int8_t *pos;
 	status_t res = FAILED;
 	
 	/* remove any preceding 0-bytes from signature */
@@ -207,7 +157,7 @@ static status_t verify_emsa_pkcs1_signature(const private_rsa_public_key_t *this
 	}
 	
 	/* unpack signature */
-	em = this->rsavp1(this, signature);
+	em_ori = em = this->rsavp1(this, signature);
 	
 	/* result should look like this:
 	 * EM = 0x00 || 0x01 || PS || 0x00 || T. 
@@ -216,98 +166,99 @@ static status_t verify_emsa_pkcs1_signature(const private_rsa_public_key_t *this
 	 */
 	
 	/* check magic bytes */
-	if ((*(em.ptr) != 0x00) || (*(em.ptr+1) != 0x01))
+	if (*(em.ptr) != 0x00 || *(em.ptr+1) != 0x01)
 	{
 		goto end;
 	}
+	em.ptr += 2;
+	em.len -= 2;
 	
 	/* find magic 0x00 */
-	pos = em.ptr + 2;
+	while (em.len > 0)
-	while (pos <= em.ptr + em.len)
 	{
-		if (*pos == 0x00)
+		if (*em.ptr == 0x00)
 		{
 			/* found magic byte, stop */
-			pos++;
+			em.ptr++;
+			em.len--;
 			break;
 		}
-		else if (*pos != 0xFF)
+		else if (*em.ptr != 0xFF)
 		{
 			/* bad padding, decryption failed ?!*/
 			goto end;
 		}
-		pos++;
+		em.ptr++;
+		em.len--;
 	}
 
-	if (pos + LARGEST_HASH_OID_SIZE > em.ptr + em.len)
+	if (em.len == 0)
 	{
-		/* not enought room for oid compare */
+		/* no digestInfo found */
 		goto end;
 	}
 	
-	if (memeq(md2_oid, pos, sizeof(md2_oid)))
+	/* parse ASN.1-based digestInfo */
 	{
-		hasher = hasher_create(HASH_MD2);
+		asn1_ctx_t ctx;
-		pos += sizeof(md2_oid);
+		chunk_t object;
-	}
+		u_int level;
-	else if (memeq(md5_oid, pos, sizeof(md5_oid)))
+		int objectID = 0;
-	{
+		hash_algorithm_t hash_algorithm;
-		hasher = hasher_create(HASH_MD5);
+
-		pos += sizeof(md5_oid);
+		asn1_init(&ctx, em, 0, FALSE, FALSE);
-	}
+
-	else if (memeq(sha1_oid, pos, sizeof(sha1_oid)))
+		while (objectID < DIGEST_INFO_ROOF)
-	{
+		{
-		hasher = hasher_create(HASH_SHA1);
+			if (!extract_object(digestInfoObjects, &objectID, &object, &level, &ctx))
-		pos += sizeof(sha1_oid);
+			{
-	}
+				goto end;
-	else if (memeq(sha256_oid, pos, sizeof(sha256_oid)))
+			}
-	{
+			if (objectID == DIGEST_INFO_ALGORITHM)
-		hasher = hasher_create(HASH_SHA256);
+			{
-		pos += sizeof(sha256_oid);
+				int hash_oid = parse_algorithmIdentifier(object, level+1, NULL);
-	}
+
-	else if (memeq(sha384_oid, pos, sizeof(sha384_oid)))
+				hash_algorithm = hasher_algorithm_from_oid(hash_oid);
-	{
+				if (hash_algorithm == HASH_UNKNOWN
-		hasher = hasher_create(HASH_SHA384);
+				|| (algorithm != HASH_UNKNOWN && hash_algorithm != algorithm))
-		pos += sizeof(sha384_oid);
+				{
-	}
+					goto end;
-	else if (memeq(sha512_oid, pos, sizeof(sha512_oid)))
+				}
-	{
+			}
-		hasher = hasher_create(HASH_SHA512);
+			else if (objectID == DIGEST_INFO_DIGEST)
-		pos += sizeof(sha512_oid);
+			{
-	}
+				chunk_t hash;
+				hasher_t *hasher = hasher_create(hash_algorithm);
+
+				if (object.len != hasher->get_hash_size(hasher))
+				{
+					/* wrong hash size */
+					hasher->destroy(hasher);
+					goto end;
+				}
+
+				/* build our own hash */
+				hasher->allocate_hash(hasher, data, &hash);
+				hasher->destroy(hasher);
 	
-	if (hasher == NULL)
+				/* compare the hashes */
-	{
+				res = memeq(object.ptr, hash.ptr, hash.len) ? SUCCESS : FAILED;
-		/* unsupported hash algorithm */
+				free(hash.ptr);
-		res = NOT_SUPPORTED;;
+			}
-		goto end;
+			objectID++;
+		}
 	}
-	
-	if (pos + hasher->get_hash_size(hasher) != em.ptr + em.len)
-	{
-		/* bad length */
-		hasher->destroy(hasher);
-		goto end;
-	}
-	
-	/* build our own hash */
-	hasher->allocate_hash(hasher, data, &hash);
-	hasher->destroy(hasher);
-	
-	/* compare the hashes */
-	res = memeq(hash.ptr, pos, hash.len) ? SUCCESS : FAILED;
-	free(hash.ptr);
 
 end:
-	free(em.ptr);
+	free(em_ori.ptr);
 	return res;
 }
-	
+
 /**
  * Implementation of rsa_public_key.get_key.
  */
 static status_t get_key(const private_rsa_public_key_t *this, chunk_t *key)
-{	
+{
 	chunk_t n, e;
 
 	n.len = this->k;
@@ -391,7 +342,7 @@ private_rsa_public_key_t *rsa_public_key_create_empty(void)
 	private_rsa_public_key_t *this = malloc_thing(private_rsa_public_key_t);
 	
 	/* public functions */
-	this->public.verify_emsa_pkcs1_signature = (status_t (*) (const rsa_public_key_t*,chunk_t,chunk_t))verify_emsa_pkcs1_signature;
+	this->public.verify_emsa_pkcs1_signature = (status_t (*) (const rsa_public_key_t*,hash_algorithm_t,chunk_t,chunk_t))verify_emsa_pkcs1_signature;
 	this->public.get_key = (status_t (*) (const rsa_public_key_t*,chunk_t*))get_key;
 	this->public.save_key = (status_t (*) (const rsa_public_key_t*,char*))save_key;
 	this->public.get_modulus = (mpz_t *(*) (const rsa_public_key_t*))get_modulus;
@@ -447,7 +398,7 @@ rsa_public_key_t *rsa_public_key_create_from_chunk(chunk_t blob)
 	
 	while (objectID < PUB_KEY_ROOF) 
 	{
-		if (!extract_object(pubkey_objects, &objectID, &object, &level, &ctx))
+		if (!extract_object(pubkeyObjects, &objectID, &object, &level, &ctx))
 		{
 			destroy(this);
 			return FALSE;

src/libstrongswan/crypto/rsa/rsa_public_key.h

@@ -29,6 +29,7 @@ typedef struct rsa_public_key_t rsa_public_key_t;
 #include <gmp.h>
 
 #include <library.h>
+#include <crypto/hashers/hasher.h>
 
 /**
  * @brief RSA public key with associated functions.
@@ -58,6 +59,7 @@ struct rsa_public_key_t {
 	 * 
 	 * @param this				rsa_public_key to use
 	 * @param data				data to sign
+	 # @param algorithm			hash algorithm the signature is based on
 	 * @param signature			signature to verify
 	 * @return
 	 * 							- SUCCESS, if signature ok
@@ -66,7 +68,9 @@ struct rsa_public_key_t {
 	 * 							- INVALID_ARG, if signature is not a signature
 	 * 							- FAILED if signature invalid or unable to verify
 	 */
-	status_t (*verify_emsa_pkcs1_signature) (const rsa_public_key_t *this, chunk_t data, chunk_t signature);
+	status_t (*verify_emsa_pkcs1_signature) (const rsa_public_key_t *this,
+											 hash_algorithm_t algorithm,
+											 chunk_t data, chunk_t signature);
 	
 	/**
 	 * @brief Gets the key.

src/libstrongswan/crypto/x509.c

@@ -807,7 +807,7 @@ static bool parse_certificate(chunk_t blob, u_int level0, private_x509_t *this)
 			case X509_OBJ_SUBJECT_PUBLIC_KEY_ALGORITHM:
 				if (parse_algorithmIdentifier(object, level, NULL) != OID_RSA_ENCRYPTION)
 				{
-					DBG2("  unsupported public key algorithm");
+					DBG1("  unsupported public key algorithm");
 					return FALSE;
 				}
 				break;
@@ -819,7 +819,7 @@ static bool parse_certificate(chunk_t blob, u_int level0, private_x509_t *this)
 				}
 				else
 				{
-					DBG2("  invalid RSA public key format");
+					DBG1("  invalid RSA public key format");
 					return FALSE;
 				}
 				break;
@@ -872,6 +872,11 @@ static bool parse_certificate(chunk_t blob, u_int level0, private_x509_t *this)
 			}
 			case X509_OBJ_ALGORITHM:
 				this->algorithm = parse_algorithmIdentifier(object, level, NULL);
+				if (this->algorithm != this->sigAlg)
+				{
+					DBG1("  signature algorithms do not agree");
+					return FALSE;
+				}
 				break;
 			case X509_OBJ_SIGNATURE:
 				this->signature = object;
@@ -1129,7 +1134,14 @@ static iterator_t *create_ocspuri_iterator(const private_x509_t *this)
  */
 static bool verify(const private_x509_t *this, const rsa_public_key_t *signer)
 {
-	return signer->verify_emsa_pkcs1_signature(signer, this->tbsCertificate, this->signature) == SUCCESS;
+	hash_algorithm_t algorithm = hasher_algorithm_from_oid(this->algorithm);
+
+	if (algorithm == HASH_UNKNOWN)
+	{
+		DBG1("  unknown signature algorithm");
+		return FALSE;
+	}
+	return signer->verify_emsa_pkcs1_signature(signer, algorithm, this->tbsCertificate, this->signature) == SUCCESS;
 }
 	
 /**
@@ -1324,8 +1336,15 @@ x509_t *x509_create_from_chunk(chunk_t chunk, u_int level)
 	this->isSelfSigned = FALSE;
 	if (this->subject->equals(this->subject, this->issuer))
 	{
+		hash_algorithm_t algorithm = hasher_algorithm_from_oid(this->algorithm);
+
+		if (algorithm == HASH_UNKNOWN)
+		{
+			destroy(this);
+			return NULL;
+		}
 		this->isSelfSigned = this->public_key->verify_emsa_pkcs1_signature(this->public_key,
-							 this->tbsCertificate, this->signature) == SUCCESS;
+							 algorithm, this->tbsCertificate, this->signature) == SUCCESS;
 	}
 	if (this->isSelfSigned)
 	{