/**
* Parse X.501 attributes
*/
bool parse_attributes(chunk_t blob, scep_attributes_t *attrs)
{
asn1_parser_t *parser;
chunk_t object;
int oid = OID_UNKNOWN;
int objectID;
bool success = FALSE;
parser = asn1_parser_create(attributesObjects, blob);
DBG(DBG_CONTROL | DBG_PARSING,
DBG_log("parsing attributes")
)
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case ATTRIBUTE_OBJ_TYPE:
oid = asn1_known_oid(object);
break;
case ATTRIBUTE_OBJ_VALUE:
if (!extract_attribute(oid, object, parser->get_level(parser), attrs))
{
goto end;
}
}
}
success = parser->success(parser);
end:
parser->destroy(parser);
return success;
}
/**
* Load a RSA public key from an ASN.1 encoded blob.
*/
static public_key_t *parse_rsa_public_key(chunk_t blob)
{
chunk_t n, e;
asn1_parser_t *parser;
chunk_t object;
int objectID;
bool success = FALSE;
parser = asn1_parser_create(pubkeyObjects, blob);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case PUB_KEY_MODULUS:
n = object;
break;
case PUB_KEY_EXPONENT:
e = object;
break;
}
}
success = parser->success(parser);
parser->destroy(parser);
if (!success)
{
return NULL;
}
return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
BUILD_RSA_MODULUS, n, BUILD_RSA_PUB_EXP, e, BUILD_END);
}
/**
* Parse PKCS#7 ContentInfo object
*/
bool pkcs7_parse_contentInfo(chunk_t blob, u_int level0, contentInfo_t *cInfo)
{
asn1_parser_t *parser;
chunk_t object;
int objectID;
bool success = FALSE;
parser = asn1_parser_create(contentInfoObjects, blob);
parser->set_top_level(parser, level0);
while (parser->iterate(parser, &objectID, &object))
{
if (objectID == PKCS7_INFO_TYPE)
{
cInfo->type = asn1_known_oid(object);
if (cInfo->type < OID_PKCS7_DATA
|| cInfo->type > OID_PKCS7_ENCRYPTED_DATA)
{
DBG1(DBG_LIB, "unknown pkcs7 content type");
goto end;
}
}
else if (objectID == PKCS7_INFO_CONTENT)
{
cInfo->content = object;
}
}
success = parser->success(parser);
end:
parser->destroy(parser);
return success;
}
/**
* Load a generic private key from an ASN.1 encoded blob
*/
static private_key_t *parse_private_key(chunk_t blob)
{
asn1_parser_t *parser;
chunk_t object, params = chunk_empty;
int objectID;
private_key_t *key = NULL;
key_type_t type = KEY_ANY;
parser = asn1_parser_create(pkinfoObjects, blob);
parser->set_flags(parser, FALSE, TRUE);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case PKINFO_PRIVATE_KEY_ALGORITHM:
{
int oid = asn1_parse_algorithmIdentifier(object,
parser->get_level(parser) + 1, ¶ms);
switch (oid)
{
case OID_RSA_ENCRYPTION:
type = KEY_RSA;
break;
case OID_EC_PUBLICKEY:
type = KEY_ECDSA;
break;
default:
/* key type not supported */
goto end;
}
break;
}
case PKINFO_PRIVATE_KEY:
{
DBG2(DBG_ASN, "-- > --");
if (params.ptr)
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY,
type, BUILD_BLOB_ALGID_PARAMS,
params, BUILD_BLOB_ASN1_DER,
object, BUILD_END);
}
else
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY,
type, BUILD_BLOB_ASN1_DER, object,
BUILD_END);
}
DBG2(DBG_ASN, "-- < --");
break;
}
}
}
end:
parser->destroy(parser);
return key;
}
/**
* Load a generic public key from an ASN.1 encoded blob
*/
static public_key_t *parse_public_key(chunk_t blob)
{
asn1_parser_t *parser;
chunk_t object;
int objectID;
public_key_t *key = NULL;
key_type_t type = KEY_ANY;
parser = asn1_parser_create(pkinfoObjects, blob);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case PKINFO_SUBJECT_PUBLIC_KEY_ALGORITHM:
{
int oid = asn1_parse_algorithmIdentifier(object,
parser->get_level(parser)+1, NULL);
if (oid == OID_RSA_ENCRYPTION || oid == OID_RSAES_OAEP)
{
type = KEY_RSA;
}
else if (oid == OID_EC_PUBLICKEY)
{
/* we need the whole subjectPublicKeyInfo for EC public keys */
key = lib->creds->create(lib->creds, CRED_PUBLIC_KEY,
KEY_ECDSA, BUILD_BLOB_ASN1_DER, blob, BUILD_END);
goto end;
}
else
{
/* key type not supported */
goto end;
}
break;
}
case PKINFO_SUBJECT_PUBLIC_KEY:
if (object.len > 0 && *object.ptr == 0x00)
{
/* skip initial bit string octet defining 0 unused bits */
object = chunk_skip(object, 1);
}
DBG2(DBG_ASN, "-- > --");
key = lib->creds->create(lib->creds, CRED_PUBLIC_KEY, type,
BUILD_BLOB_ASN1_DER, object, BUILD_END);
DBG2(DBG_ASN, "-- < --");
break;
}
}
end:
parser->destroy(parser);
return key;
}
static void run_parser_test(const asn1Object_t *objects, int id,
asn1_test_t *test)
{
asn1_parser_t *parser;
chunk_t object;
int objectID, count = 0;
bool success;
parser = asn1_parser_create(objects, test->blob);
while (parser->iterate(parser, &objectID, &object))
{
if (objectID == id)
{
count++;
}
}
success = parser->success(parser);
parser->destroy(parser);
ck_assert(success == test->success && count == test->count);
}
/**
* Load an encrypted private key from an ASN.1 encoded blob
* Schemes per PKCS#5 (RFC 2898)
*/
static private_key_t *parse_encrypted_private_key(chunk_t blob)
{
asn1_parser_t *parser;
chunk_t object;
int objectID;
private_key_t *key = NULL;
pkcs5_t *pkcs5 = NULL;
parser = asn1_parser_create(encryptedPKIObjects, blob);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case EPKINFO_ENCRYPTION_ALGORITHM:
{
pkcs5 = pkcs5_from_algorithmIdentifier(object,
parser->get_level(parser) + 1);
if (!pkcs5)
{
goto end;
}
break;
}
case EPKINFO_ENCRYPTED_DATA:
{
key = decrypt_private_key(pkcs5, object);
break;
}
}
}
end:
DESTROY_IF(pkcs5);
parser->destroy(parser);
return key;
}
/**
* Load a RSA private key from a ASN1 encoded blob.
*/
static private_key_t *parse_rsa_private_key(chunk_t blob)
{
chunk_t n, e, d, p, q, exp1, exp2, coeff;
asn1_parser_t *parser;
chunk_t object;
int objectID ;
bool success = FALSE;
parser = asn1_parser_create(privkeyObjects, blob);
parser->set_flags(parser, FALSE, TRUE);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case PRIV_KEY_VERSION:
if (object.len > 0 && *object.ptr != 0)
{
DBG1(DBG_ASN, "PKCS#1 private key format is not version 1");
goto end;
}
break;
case PRIV_KEY_MODULUS:
n = object;
break;
case PRIV_KEY_PUB_EXP:
e = object;
break;
case PRIV_KEY_PRIV_EXP:
d = object;
break;
case PRIV_KEY_PRIME1:
p = object;
break;
case PRIV_KEY_PRIME2:
q = object;
break;
case PRIV_KEY_EXP1:
exp1 = object;
break;
case PRIV_KEY_EXP2:
exp2 = object;
break;
case PRIV_KEY_COEFF:
coeff = object;
break;
}
}
success = parser->success(parser);
end:
parser->destroy(parser);
if (!success)
{
return NULL;
}
return lib->creds->create(lib->creds, CRED_PRIVATE_KEY, KEY_RSA,
BUILD_RSA_MODULUS, n, BUILD_RSA_PUB_EXP, e, BUILD_RSA_PRIV_EXP, d,
BUILD_RSA_PRIME1, p, BUILD_RSA_PRIME2, q, BUILD_RSA_EXP1, exp1,
BUILD_RSA_EXP2, exp2, BUILD_RSA_COEFF, coeff, BUILD_END);
}
/**
* Load a generic private key from an ASN.1 encoded blob
*/
static private_key_t *parse_private_key(chunk_t blob)
{
asn1_parser_t *parser;
chunk_t object, params = chunk_empty;
int objectID;
private_key_t *key = NULL;
key_type_t type = KEY_ANY;
builder_part_t part = BUILD_BLOB_ASN1_DER;
parser = asn1_parser_create(pkinfoObjects, blob);
parser->set_flags(parser, FALSE, TRUE);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case PKINFO_PRIVATE_KEY_ALGORITHM:
{
int oid = asn1_parse_algorithmIdentifier(object,
parser->get_level(parser) + 1, ¶ms);
switch (oid)
{
case OID_RSASSA_PSS:
/* TODO: parameters associated with such keys should be
* treated as restrictions later when signing (the type
* itself is already a restriction). However, the
* builders currently don't expect any parameters for
* RSA keys (we also only pass along the params, not the
* exact type, so we'd have to guess that params
* indicate RSA/PSS, but they are optional so that won't
* work for keys without specific restrictions) */
params = chunk_empty;
/* fall-through */
case OID_RSA_ENCRYPTION:
type = KEY_RSA;
break;
case OID_EC_PUBLICKEY:
type = KEY_ECDSA;
break;
case OID_ED25519:
type = KEY_ED25519;
part = BUILD_EDDSA_PRIV_ASN1_DER;
break;
case OID_ED448:
type = KEY_ED448;
part = BUILD_EDDSA_PRIV_ASN1_DER;
break;
default:
/* key type not supported */
goto end;
}
break;
}
case PKINFO_PRIVATE_KEY:
{
DBG2(DBG_ASN, "-- > --");
if (params.ptr)
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY,
type, BUILD_BLOB_ALGID_PARAMS,
params, part, object, BUILD_END);
}
else
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY,
type, part, object, BUILD_END);
}
DBG2(DBG_ASN, "-- < --");
break;
}
}
}
end:
parser->destroy(parser);
return key;
}
/**
* Parse a PKCS#7 envelopedData object
*/
bool pkcs7_parse_envelopedData(chunk_t blob, chunk_t *data,
chunk_t serialNumber,
private_key_t *key)
{
asn1_parser_t *parser;
chunk_t object;
chunk_t iv = chunk_empty;
chunk_t symmetric_key = chunk_empty;
chunk_t encrypted_content = chunk_empty;
crypter_t *crypter = NULL;
int enc_alg = OID_UNKNOWN;
int content_enc_alg = OID_UNKNOWN;
int version;
int objectID;
bool success = FALSE;
contentInfo_t cInfo = empty_contentInfo;
*data = chunk_empty;
if (!pkcs7_parse_contentInfo(blob, 0, &cInfo))
{
goto failed;
}
if (cInfo.type != OID_PKCS7_ENVELOPED_DATA)
{
DBG1(DBG_LIB, "pkcs7 content type is not envelopedData");
goto failed;
}
parser = asn1_parser_create(envelopedDataObjects, cInfo.content);
parser->set_top_level(parser, 2);
while (parser->iterate(parser, &objectID, &object))
{
u_int level = parser->get_level(parser);
switch (objectID)
{
case PKCS7_ENVELOPED_VERSION:
version = object.len ? (int)*object.ptr : 0;
DBG2(DBG_LIB, " v%d", version);
if (version != 0)
{
DBG1(DBG_LIB, "envelopedData version is not 0");
goto end;
}
break;
case PKCS7_RECIPIENT_INFO_VERSION:
version = object.len ? (int)*object.ptr : 0;
DBG2(DBG_LIB, " v%d", version);
if (version != 0)
{
DBG1(DBG_LIB, "recipient info version is not 0");
goto end;
}
break;
case PKCS7_ISSUER:
{
identification_t *issuer = identification_create_from_encoding(
ID_DER_ASN1_DN, object);
DBG2(DBG_LIB, " \"%Y\"", issuer);
issuer->destroy(issuer);
break;
}
case PKCS7_SERIAL_NUMBER:
if (!chunk_equals(serialNumber, object))
{
DBG1(DBG_LIB, "serial numbers do not match");
goto end;
}
break;
case PKCS7_ENCRYPTION_ALG:
enc_alg = asn1_parse_algorithmIdentifier(object, level, NULL);
if (enc_alg != OID_RSA_ENCRYPTION)
{
DBG1(DBG_LIB, "only rsa encryption supported");
goto end;
}
break;
case PKCS7_ENCRYPTED_KEY:
if (!key->decrypt(key, ENCRYPT_RSA_PKCS1, object, &symmetric_key))
{
DBG1(DBG_LIB, "symmetric key could not be decrypted with rsa");
goto end;
}
DBG4(DBG_LIB, "symmetric key %B", &symmetric_key);
break;
case PKCS7_CONTENT_TYPE:
if (asn1_known_oid(object) != OID_PKCS7_DATA)
{
DBG1(DBG_LIB, "encrypted content not of type pkcs7 data");
goto end;
}
break;
case PKCS7_CONTENT_ENC_ALGORITHM:
content_enc_alg = asn1_parse_algorithmIdentifier(object, level, &iv);
if (content_enc_alg == OID_UNKNOWN)
{
DBG1(DBG_LIB, "unknown content encryption algorithm");
goto end;
}
if (!asn1_parse_simple_object(&iv, ASN1_OCTET_STRING, level+1, "IV"))
{
DBG1(DBG_LIB, "IV could not be parsed");
goto end;
}
break;
case PKCS7_ENCRYPTED_CONTENT:
encrypted_content = object;
break;
}
}
success = parser->success(parser);
end:
parser->destroy(parser);
if (!success)
{
goto failed;
}
success = FALSE;
/* decrypt the content */
{
encryption_algorithm_t alg;
size_t key_size;
crypter_t *crypter;
alg = encryption_algorithm_from_oid(content_enc_alg, &key_size);
if (alg == ENCR_UNDEFINED)
{
DBG1(DBG_LIB, "unsupported content encryption algorithm");
goto failed;
}
crypter = lib->crypto->create_crypter(lib->crypto, alg, key_size);
if (crypter == NULL)
{
DBG1(DBG_LIB, "crypter %N not available", encryption_algorithm_names, alg);
goto failed;
}
if (symmetric_key.len != crypter->get_key_size(crypter))
{
DBG1(DBG_LIB, "symmetric key length %d is wrong", symmetric_key.len);
goto failed;
}
if (iv.len != crypter->get_iv_size(crypter))
{
DBG1(DBG_LIB, "IV length %d is wrong", iv.len);
goto failed;
}
crypter->set_key(crypter, symmetric_key);
crypter->decrypt(crypter, encrypted_content, iv, data);
DBG4(DBG_LIB, "decrypted content with padding: %B", data);
}
/* remove the padding */
{
u_char *pos = data->ptr + data->len - 1;
u_char pattern = *pos;
size_t padding = pattern;
if (padding > data->len)
{
DBG1(DBG_LIB, "padding greater than data length");
goto failed;
}
data->len -= padding;
while (padding-- > 0)
{
if (*pos-- != pattern)
{
DBG1(DBG_LIB, "wrong padding pattern");
goto failed;
}
}
}
success = TRUE;
failed:
DESTROY_IF(crypter);
chunk_clear(&symmetric_key);
if (!success)
{
free(data->ptr);
}
return success;
}
/**
* Parse a PKCS#7 signedData object
*/
bool pkcs7_parse_signedData(chunk_t blob, contentInfo_t *data,
linked_list_t *certs,
chunk_t *attributes, certificate_t *cacert)
{
asn1_parser_t *parser;
chunk_t object;
int digest_alg = OID_UNKNOWN;
int enc_alg = OID_UNKNOWN;
int signerInfos = 0;
int version;
int objectID;
bool success = FALSE;
contentInfo_t cInfo = empty_contentInfo;
chunk_t encrypted_digest = chunk_empty;
if (!pkcs7_parse_contentInfo(blob, 0, &cInfo))
{
return FALSE;
}
if (cInfo.type != OID_PKCS7_SIGNED_DATA)
{
DBG1(DBG_LIB, "pkcs7 content type is not signedData");
return FALSE;
}
parser = asn1_parser_create(signedDataObjects, cInfo.content);
parser->set_top_level(parser, 2);
while (parser->iterate(parser, &objectID, &object))
{
u_int level = parser->get_level(parser);
switch (objectID)
{
case PKCS7_SIGNED_VERSION:
version = object.len ? (int)*object.ptr : 0;
DBG2(DBG_LIB, " v%d", version);
break;
case PKCS7_DIGEST_ALG:
digest_alg = asn1_parse_algorithmIdentifier(object, level, NULL);
break;
case PKCS7_SIGNED_CONTENT_INFO:
if (data != NULL)
{
pkcs7_parse_contentInfo(object, level, data);
}
break;
case PKCS7_SIGNED_CERT:
{
certificate_t *cert;
DBG2(DBG_LIB, " parsing pkcs7-wrapped certificate");
cert = lib->creds->create(lib->creds,
CRED_CERTIFICATE, CERT_X509,
BUILD_BLOB_ASN1_DER, object,
BUILD_END);
if (cert)
{
certs->insert_last(certs, cert);
}
}
break;
case PKCS7_SIGNER_INFO:
signerInfos++;
DBG2(DBG_LIB, " signer #%d", signerInfos);
break;
case PKCS7_SIGNER_INFO_VERSION:
version = object.len ? (int)*object.ptr : 0;
DBG2(DBG_LIB, " v%d", version);
break;
case PKCS7_SIGNED_ISSUER:
{
identification_t *issuer = identification_create_from_encoding(
ID_DER_ASN1_DN, object);
DBG2(DBG_LIB, " \"%Y\"", issuer);
issuer->destroy(issuer);
break;
}
case PKCS7_AUTH_ATTRIBUTES:
if (attributes != NULL)
{
*attributes = object;
*attributes->ptr = ASN1_SET;
}
break;
case PKCS7_DIGEST_ALGORITHM:
digest_alg = asn1_parse_algorithmIdentifier(object, level, NULL);
break;
case PKCS7_DIGEST_ENC_ALGORITHM:
enc_alg = asn1_parse_algorithmIdentifier(object, level, NULL);
break;
case PKCS7_ENCRYPTED_DIGEST:
encrypted_digest = object;
}
}
success = parser->success(parser);
parser->destroy(parser);
if (!success)
{
return FALSE;
}
/* check the signature only if a cacert is available */
if (cacert != NULL)
{
public_key_t *key;
signature_scheme_t scheme;
scheme = signature_scheme_from_oid(digest_alg);
if (scheme == SIGN_UNKNOWN)
{
DBG1(DBG_LIB, "unsupported signature scheme");
return FALSE;
}
if (signerInfos == 0)
{
DBG1(DBG_LIB, "no signerInfo object found");
return FALSE;
}
else if (signerInfos > 1)
{
DBG1(DBG_LIB, "more than one signerInfo object found");
return FALSE;
}
if (attributes->ptr == NULL)
{
DBG1(DBG_LIB, "no authenticatedAttributes object found");
return FALSE;
}
if (enc_alg != OID_RSA_ENCRYPTION)
{
DBG1(DBG_LIB, "only RSA digest encryption supported");
return FALSE;
}
/* verify the signature */
key = cacert->get_public_key(cacert);
if (key == NULL)
{
DBG1(DBG_LIB, "no public key found in CA certificate");
return FALSE;
}
if (key->verify(key, scheme, *attributes, encrypted_digest))
{
DBG2(DBG_LIB, "signature is valid");
}
else
{
DBG1(DBG_LIB, "invalid signature");
success = FALSE;
}
key->destroy(key);
}
return success;
}
