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check hash algorithms used in signatures

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This commit is contained in:
Andreas Steffen
2007-09-11 20:10:38 +00:00
parent dd968b9b20
commit 2f9f5149c4
8 changed files with 194 additions and 148 deletions
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src/libstrongswan/crypto/rsa/rsa_public_key.c
+82 -131
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@@ -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 */
static const asn1Object_t pubkey_objects[] = {
/* ASN.1 definition of RSApublicKey */
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 hash;
chunk_t em;
u_int8_t *pos;
chunk_t em_ori, em;
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 (pos <= em.ptr + em.len)
while (em.len > 0)
{
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);
pos += sizeof(md2_oid);
}
else if (memeq(md5_oid, pos, sizeof(md5_oid)))
{
hasher = hasher_create(HASH_MD5);
pos += sizeof(md5_oid);
}
else if (memeq(sha1_oid, pos, sizeof(sha1_oid)))
{
hasher = hasher_create(HASH_SHA1);
pos += sizeof(sha1_oid);
}
else if (memeq(sha256_oid, pos, sizeof(sha256_oid)))
{
hasher = hasher_create(HASH_SHA256);
pos += sizeof(sha256_oid);
}
else if (memeq(sha384_oid, pos, sizeof(sha384_oid)))
{
hasher = hasher_create(HASH_SHA384);
pos += sizeof(sha384_oid);
}
else if (memeq(sha512_oid, pos, sizeof(sha512_oid)))
{
hasher = hasher_create(HASH_SHA512);
pos += sizeof(sha512_oid);
}
asn1_ctx_t ctx;
chunk_t object;
u_int level;
int objectID = 0;
hash_algorithm_t hash_algorithm;
asn1_init(&ctx, em, 0, FALSE, FALSE);
while (objectID < DIGEST_INFO_ROOF)
{
if (!extract_object(digestInfoObjects, &objectID, &object, &level, &ctx))
{
goto end;
}
if (objectID == DIGEST_INFO_ALGORITHM)
{
int hash_oid = parse_algorithmIdentifier(object, level+1, NULL);
hash_algorithm = hasher_algorithm_from_oid(hash_oid);
if (hash_algorithm == HASH_UNKNOWN
|| (algorithm != HASH_UNKNOWN && hash_algorithm != algorithm))
{
goto end;
}
}
else if (objectID == DIGEST_INFO_DIGEST)
{
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)
{
/* unsupported hash algorithm */
res = NOT_SUPPORTED;;
goto end;
/* compare the hashes */
res = memeq(object.ptr, hash.ptr, hash.len) ? SUCCESS : FAILED;
free(hash.ptr);
}
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;