/**
* Parse an EC domain parameter identifier as defined in RFC 5656
*/
static chunk_t parse_ec_identifier(chunk_t identifier)
{
chunk_t oid = chunk_empty;
if (chunk_equals(identifier, chunk_from_str("nistp256")))
{
oid = asn1_build_known_oid(OID_PRIME256V1);
}
else if (chunk_equals(identifier, chunk_from_str("nistp384")))
{
oid = asn1_build_known_oid(OID_SECT384R1);
}
else if (chunk_equals(identifier, chunk_from_str("nistp521")))
{
oid = asn1_build_known_oid(OID_SECT521R1);
}
else
{
char ascii[64];
if (snprintf(ascii, sizeof(ascii), "%.*s", (int)identifier.len,
identifier.ptr) < sizeof(ascii))
{
oid = asn1_wrap(ASN1_OID, "m", asn1_oid_from_string(ascii));
}
}
return oid;
}
/**
* @brief Builds a contentType attribute
*
* @return ASN.1 encoded contentType attribute
*/
chunk_t pkcs7_contentType_attribute(void)
{
return asn1_wrap(ASN1_SEQUENCE, "mm",
asn1_build_known_oid(OID_PKCS9_CONTENT_TYPE),
asn1_wrap(ASN1_SET, "m",
asn1_build_known_oid(OID_PKCS7_DATA)));
}
/**
* build a DER-encoded contentInfo object
*/
static chunk_t pkcs7_build_contentInfo(contentInfo_t *cInfo)
{
return (cInfo->content.ptr) ?
asn1_wrap(ASN1_SEQUENCE, "mm",
asn1_build_known_oid(cInfo->type),
asn1_simple_object(ASN1_CONTEXT_C_0, cInfo->content)) :
asn1_build_known_oid(cInfo->type);
}
END_TEST
/*******************************************************************************
* parse_algorithm_identifier
*/
START_TEST(test_asn1_parse_algorithmIdentifier)
{
typedef struct {
int alg;
bool empty;
chunk_t parameters;
} testdata_t;
testdata_t test[] = {
{ OID_ECDSA_WITH_SHA1, TRUE, chunk_empty },
{ OID_SHA1_WITH_RSA, TRUE, chunk_from_chars(0x05, 0x00) },
{ OID_3DES_EDE_CBC, FALSE, chunk_from_chars(0x04, 0x01, 0xaa) },
{ OID_PBKDF2, FALSE, chunk_from_chars(0x30, 0x01, 0xaa) }
};
chunk_t algid, parameters;
int i, alg;
for (i = 0; i < countof(test); i++)
{
algid = asn1_wrap(ASN1_SEQUENCE, "mc",
asn1_build_known_oid(test[i].alg), test[i].parameters);
parameters = chunk_empty;
if (i == 2)
{
alg = asn1_parse_algorithmIdentifier(algid, 0, NULL);
}
else
{
alg = asn1_parse_algorithmIdentifier(algid, 0, ¶meters);
if (test[i].empty)
{
ck_assert(parameters.len == 0 && parameters.ptr == NULL);
}
else
{
ck_assert(chunk_equals(parameters, test[i].parameters));
}
}
ck_assert(alg == test[i].alg);
chunk_free(&algid);
}
}
/**
* @brief Builds a messageDigest attribute
*
*
* @param[in] blob content to create digest of
* @param[in] digest_alg digest algorithm to be used
* @return ASN.1 encoded messageDigest attribute
*
*/
chunk_t pkcs7_messageDigest_attribute(chunk_t content, int digest_alg)
{
chunk_t digest;
hash_algorithm_t hash_alg;
hasher_t *hasher;
hash_alg = hasher_algorithm_from_oid(digest_alg);
hasher = lib->crypto->create_hasher(lib->crypto, hash_alg);
hasher->allocate_hash(hasher, content, &digest);
hasher->destroy(hasher);
return asn1_wrap(ASN1_SEQUENCE, "mm",
asn1_build_known_oid(OID_PKCS9_MESSAGE_DIGEST),
asn1_wrap(ASN1_SET, "m",
asn1_wrap(ASN1_OCTET_STRING, "m", digest)));
}
/*
* Defined in header.
*/
chunk_t asn1_algorithmIdentifier(int oid)
{
chunk_t parameters;
/* some algorithmIdentifiers have a NULL parameters field and some do not */
switch (oid)
{
case OID_ECDSA_WITH_SHA1:
case OID_ECDSA_WITH_SHA224:
case OID_ECDSA_WITH_SHA256:
case OID_ECDSA_WITH_SHA384:
case OID_ECDSA_WITH_SHA512:
parameters = chunk_empty;
break;
default:
parameters = asn1_simple_object(ASN1_NULL, chunk_empty);
break;
}
return asn1_wrap(ASN1_SEQUENCE, "mm", asn1_build_known_oid(oid), parameters);
}
END_TEST
/*******************************************************************************
* build_known_oid
*/
START_TEST(test_asn1_build_known_oid)
{
typedef struct {
int n;
chunk_t oid;
} testdata_t;
testdata_t test[] = {
{ OID_UNKNOWN, chunk_empty },
{ OID_MAX, chunk_empty },
{ OID_COUNTRY, chunk_from_chars(0x06, 0x03, 0x55, 0x04, 0x06) },
{ OID_STRONGSWAN, chunk_from_chars(0x06, 0x09, 0x2b, 0x06, 0x01, 0x04,
0x01, 0x82, 0xa0, 0x2a, 0x01) }
};
int i;
chunk_t oid = chunk_empty;
for (i = 0; i < countof(test); i++)
{
oid = asn1_build_known_oid(test[i].n);
if (test[i].oid.len == 0)
{
ck_assert(oid.len == 0 && oid.ptr == NULL);
}
else
{
ck_assert(chunk_equals(oid, test[i].oid));
chunk_free(&oid);
}
}
}
/**
* Load a generic public key from an SSH key blob
*/
static sshkey_public_key_t *parse_public_key(chunk_t blob)
{
bio_reader_t *reader;
chunk_t format;
reader = bio_reader_create(blob);
if (!reader->read_data32(reader, &format))
{
DBG1(DBG_LIB, "invalid key format in SSH key");
reader->destroy(reader);
return NULL;
}
if (chunk_equals(format, chunk_from_str("ssh-rsa")))
{
chunk_t n, e;
if (!reader->read_data32(reader, &e) ||
!reader->read_data32(reader, &n))
{
DBG1(DBG_LIB, "invalid RSA key in SSH key");
reader->destroy(reader);
return NULL;
}
reader->destroy(reader);
return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
BUILD_RSA_MODULUS, n, BUILD_RSA_PUB_EXP, e, BUILD_END);
}
else if (format.len > strlen(ECDSA_PREFIX) &&
strneq(format.ptr, ECDSA_PREFIX, strlen(ECDSA_PREFIX)))
{
chunk_t ec_blob, identifier, q, oid, encoded;
sshkey_public_key_t *key;
ec_blob = reader->peek(reader);
reader->destroy(reader);
reader = bio_reader_create(ec_blob);
if (!reader->read_data32(reader, &identifier) ||
!reader->read_data32(reader, &q))
{
DBG1(DBG_LIB, "invalid ECDSA key in SSH key");
reader->destroy(reader);
return NULL;
}
oid = parse_ec_identifier(identifier);
if (!oid.ptr)
{
DBG1(DBG_LIB, "invalid ECDSA key identifier in SSH key");
reader->destroy(reader);
return NULL;
}
reader->destroy(reader);
/* build key from subjectPublicKeyInfo */
encoded = asn1_wrap(ASN1_SEQUENCE, "mm",
asn1_wrap(ASN1_SEQUENCE, "mm",
asn1_build_known_oid(OID_EC_PUBLICKEY), oid),
asn1_bitstring("c", q));
key = lib->creds->create(lib->creds, CRED_PUBLIC_KEY,
KEY_ECDSA, BUILD_BLOB_ASN1_DER, encoded, BUILD_END);
chunk_free(&encoded);
return key;
}
DBG1(DBG_LIB, "unsupported SSH key format %.*s", (int)format.len,
format.ptr);
reader->destroy(reader);
return NULL;
}
/**
* create a symmetrically encrypted pkcs7 contentInfo object
*/
chunk_t pkcs7_build_envelopedData(chunk_t data, certificate_t *cert, int enc_alg)
{
encryption_algorithm_t alg;
size_t alg_key_size;
chunk_t symmetricKey, protectedKey, iv, in, out;
crypter_t *crypter;
alg = encryption_algorithm_from_oid(enc_alg, &alg_key_size);
crypter = lib->crypto->create_crypter(lib->crypto, alg,
alg_key_size/BITS_PER_BYTE);
if (crypter == NULL)
{
DBG1(DBG_LIB, "crypter for %N not available", encryption_algorithm_names, alg);
return chunk_empty;
}
/* generate a true random symmetric encryption key and a pseudo-random iv */
{
rng_t *rng;
rng = lib->crypto->create_rng(lib->crypto, RNG_TRUE);
rng->allocate_bytes(rng, crypter->get_key_size(crypter), &symmetricKey);
DBG4(DBG_LIB, "symmetric encryption key %B", &symmetricKey);
rng->destroy(rng);
rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
rng->allocate_bytes(rng, crypter->get_iv_size(crypter), &iv);
DBG4(DBG_LIB, "initialization vector: %B", &iv);
rng->destroy(rng);
}
/* pad the data to a multiple of the block size */
{
size_t block_size = crypter->get_block_size(crypter);
size_t padding = block_size - data.len % block_size;
in.len = data.len + padding;
in.ptr = malloc(in.len);
DBG2(DBG_LIB, "padding %u bytes of data to multiple block size of %u bytes",
data.len, in.len);
/* copy data */
memcpy(in.ptr, data.ptr, data.len);
/* append padding */
memset(in.ptr + data.len, padding, padding);
}
DBG3(DBG_LIB, "padded unencrypted data %B", &in);
/* symmetric encryption of data object */
crypter->set_key(crypter, symmetricKey);
crypter->encrypt(crypter, in, iv, &out);
crypter->destroy(crypter);
chunk_clear(&in);
DBG3(DBG_LIB, "encrypted data %B", &out);
/* protect symmetric key by public key encryption */
{
public_key_t *key = cert->get_public_key(cert);
if (key == NULL)
{
DBG1(DBG_LIB, "public key not found in encryption certificate");
chunk_clear(&symmetricKey);
chunk_free(&iv);
chunk_free(&out);
return chunk_empty;
}
key->encrypt(key, ENCRYPT_RSA_PKCS1, symmetricKey, &protectedKey);
key->destroy(key);
}
/* build pkcs7 enveloped data object */
{
chunk_t contentEncryptionAlgorithm = asn1_wrap(ASN1_SEQUENCE, "mm"
, asn1_build_known_oid(enc_alg)
, asn1_simple_object(ASN1_OCTET_STRING, iv));
chunk_t encryptedContentInfo = asn1_wrap(ASN1_SEQUENCE, "mmm"
, asn1_build_known_oid(OID_PKCS7_DATA)
, contentEncryptionAlgorithm
, asn1_wrap(ASN1_CONTEXT_S_0, "m", out));
chunk_t encryptedKey = asn1_wrap(ASN1_OCTET_STRING, "m"
, protectedKey);
chunk_t recipientInfo = asn1_wrap(ASN1_SEQUENCE, "cmmm"
, ASN1_INTEGER_0
, pkcs7_build_issuerAndSerialNumber(cert)
, asn1_algorithmIdentifier(OID_RSA_ENCRYPTION)
, encryptedKey);
chunk_t cInfo;
contentInfo_t envelopedData;
envelopedData.type = OID_PKCS7_ENVELOPED_DATA;
envelopedData.content = asn1_wrap(ASN1_SEQUENCE, "cmm"
, ASN1_INTEGER_0
, asn1_wrap(ASN1_SET, "m", recipientInfo)
, encryptedContentInfo);
cInfo = pkcs7_build_contentInfo(&envelopedData);
DBG3(DBG_LIB, "envelopedData %B", &cInfo);
chunk_free(&envelopedData.content);
chunk_free(&iv);
chunk_clear(&symmetricKey);
return cInfo;
}
}
