Refactor: Separate asymmetric key types.
Change-Id: I3368798a8ecea319bb0bfcd6ff24e9a7b6287c80
diff --git a/dsa_key.cpp b/dsa_key.cpp
new file mode 100644
index 0000000..65c05b7
--- /dev/null
+++ b/dsa_key.cpp
@@ -0,0 +1,220 @@
+/*
+ * Copyright 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "dsa_key.h"
+#include "dsa_operation.h"
+#include "openssl_utils.h"
+#include "unencrypted_key_blob.h"
+
+namespace keymaster {
+
+const uint32_t DSA_DEFAULT_KEY_SIZE = 2048;
+
+template <keymaster_tag_t Tag>
+static void GetDsaParamData(const AuthorizationSet& auths, TypedTag<KM_BIGNUM, Tag> tag,
+ keymaster_blob_t* blob) {
+ if (!auths.GetTagValue(tag, blob))
+ blob->data = NULL;
+}
+
+// Store the specified DSA param in auths
+template <keymaster_tag_t Tag>
+static void SetDsaParamData(AuthorizationSet* auths, TypedTag<KM_BIGNUM, Tag> tag, BIGNUM* number) {
+ keymaster_blob_t blob;
+ convert_bn_to_blob(number, &blob);
+ auths->push_back(Authorization(tag, blob));
+ delete[] blob.data;
+}
+
+DsaKey* DsaKey::GenerateKey(const AuthorizationSet& key_description, const Logger& logger,
+ keymaster_error_t* error) {
+ if (!error)
+ return NULL;
+
+ AuthorizationSet authorizations(key_description);
+
+ uint32_t key_size = DSA_DEFAULT_KEY_SIZE;
+ if (!authorizations.GetTagValue(TAG_KEY_SIZE, &key_size))
+ authorizations.push_back(Authorization(TAG_KEY_SIZE, key_size));
+
+ UniquePtr<DSA, DSA_Delete> dsa_key(DSA_new());
+ UniquePtr<EVP_PKEY, EVP_PKEY_Delete> pkey(EVP_PKEY_new());
+ if (dsa_key.get() == NULL || pkey.get() == NULL) {
+ *error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
+ return NULL;
+ }
+
+ // If anything goes wrong in the next section, it's a param problem.
+ *error = KM_ERROR_INVALID_DSA_PARAMS;
+
+ keymaster_blob_t g_blob;
+ keymaster_blob_t p_blob;
+ keymaster_blob_t q_blob;
+ GetDsaParamData(authorizations, TAG_DSA_GENERATOR, &g_blob);
+ GetDsaParamData(authorizations, TAG_DSA_P, &p_blob);
+ GetDsaParamData(authorizations, TAG_DSA_Q, &q_blob);
+
+ if (g_blob.data == NULL && p_blob.data == NULL && q_blob.data == NULL) {
+ logger.info("DSA parameters unspecified, generating them for key size %d", key_size);
+ if (!DSA_generate_parameters_ex(dsa_key.get(), key_size, NULL /* seed */, 0 /* seed_len */,
+ NULL /* counter_ret */, NULL /* h_ret */,
+ NULL /* callback */)) {
+ logger.severe("DSA parameter generation failed.");
+ return NULL;
+ }
+
+ SetDsaParamData(&authorizations, TAG_DSA_GENERATOR, dsa_key->g);
+ SetDsaParamData(&authorizations, TAG_DSA_P, dsa_key->p);
+ SetDsaParamData(&authorizations, TAG_DSA_Q, dsa_key->q);
+ } else if (g_blob.data == NULL || p_blob.data == NULL || q_blob.data == NULL) {
+ logger.severe("Some DSA parameters provided. Provide all or none");
+ return NULL;
+ } else {
+ // All params provided. Use them.
+ dsa_key->g = BN_bin2bn(g_blob.data, g_blob.data_length, NULL);
+ dsa_key->p = BN_bin2bn(p_blob.data, p_blob.data_length, NULL);
+ dsa_key->q = BN_bin2bn(q_blob.data, q_blob.data_length, NULL);
+ if (dsa_key->g == NULL || dsa_key->p == NULL || dsa_key->q == NULL) {
+ return NULL;
+ }
+ }
+
+ if (!DSA_generate_key(dsa_key.get())) {
+ *error = KM_ERROR_UNKNOWN_ERROR;
+ return NULL;
+ }
+
+ DsaKey* new_key = new DsaKey(dsa_key.release(), authorizations, logger);
+ *error = new_key ? KM_ERROR_OK : KM_ERROR_MEMORY_ALLOCATION_FAILED;
+ return new_key;
+}
+
+template <keymaster_tag_t T>
+keymaster_error_t GetOrCheckDsaParam(TypedTag<KM_BIGNUM, T> tag, BIGNUM* bn,
+ AuthorizationSet* auths) {
+ keymaster_blob_t blob;
+ if (auths->GetTagValue(tag, &blob)) {
+ // value specified, make sure it matches
+ UniquePtr<BIGNUM, BIGNUM_Delete> extracted_bn(BN_bin2bn(blob.data, blob.data_length, NULL));
+ if (extracted_bn.get() == NULL)
+ return KM_ERROR_MEMORY_ALLOCATION_FAILED;
+ if (BN_cmp(extracted_bn.get(), bn) != 0)
+ return KM_ERROR_IMPORT_PARAMETER_MISMATCH;
+ } else {
+ // value not specified, add it
+ UniquePtr<uint8_t[]> data(new uint8_t[BN_num_bytes(bn)]);
+ BN_bn2bin(bn, data.get());
+ auths->push_back(tag, data.get(), BN_num_bytes(bn));
+ }
+ return KM_ERROR_OK;
+}
+
+static size_t calculate_key_size_in_bits(DSA* dsa_key) {
+ // Openssl provides no convenient way to get a DSA key size, but dsa_key->p is L bits long.
+ // There may be some leading zeros that mess up this calculation, but DSA key sizes are also
+ // constrained to be multiples of 64 bits. So the key size is the bit length of p rounded up to
+ // the nearest 64.
+ return ((BN_num_bytes(dsa_key->p) * 8) + 63) / 64 * 64;
+}
+
+/* static */
+DsaKey* DsaKey::ImportKey(const AuthorizationSet& key_description, EVP_PKEY* pkey,
+ const Logger& logger, keymaster_error_t* error) {
+ if (!error)
+ return NULL;
+ *error = KM_ERROR_UNKNOWN_ERROR;
+
+ UniquePtr<DSA, DSA_Delete> dsa_key(EVP_PKEY_get1_DSA(pkey));
+ if (!dsa_key.get())
+ return NULL;
+
+ AuthorizationSet authorizations(key_description);
+
+ *error = GetOrCheckDsaParam(TAG_DSA_GENERATOR, dsa_key->g, &authorizations);
+ if (*error != KM_ERROR_OK)
+ return NULL;
+
+ *error = GetOrCheckDsaParam(TAG_DSA_P, dsa_key->p, &authorizations);
+ if (*error != KM_ERROR_OK)
+ return NULL;
+
+ *error = GetOrCheckDsaParam(TAG_DSA_Q, dsa_key->q, &authorizations);
+ if (*error != KM_ERROR_OK)
+ return NULL;
+
+ uint32_t key_size_in_bits;
+ if (authorizations.GetTagValue(TAG_KEY_SIZE, &key_size_in_bits)) {
+ // key_bits specified, make sure it matches the key.
+ if (key_size_in_bits != calculate_key_size_in_bits(dsa_key.get())) {
+ *error = KM_ERROR_IMPORT_PARAMETER_MISMATCH;
+ return NULL;
+ }
+ } else {
+ // key_size_bits not specified, add it.
+ authorizations.push_back(TAG_KEY_SIZE, calculate_key_size_in_bits(dsa_key.get()));
+ }
+
+ keymaster_algorithm_t algorithm;
+ if (authorizations.GetTagValue(TAG_ALGORITHM, &algorithm)) {
+ if (algorithm != KM_ALGORITHM_DSA) {
+ *error = KM_ERROR_IMPORT_PARAMETER_MISMATCH;
+ return NULL;
+ }
+ } else {
+ authorizations.push_back(TAG_ALGORITHM, KM_ALGORITHM_DSA);
+ }
+
+ // Don't bother with the other parameters. If the necessary padding, digest, purpose, etc. are
+ // missing, the error will be diagnosed when the key is used (when auth checking is
+ // implemented).
+ *error = KM_ERROR_OK;
+ return new DsaKey(dsa_key.release(), authorizations, logger);
+}
+
+DsaKey::DsaKey(const UnencryptedKeyBlob& blob, const Logger& logger, keymaster_error_t* error)
+ : AsymmetricKey(blob, logger) {
+ if (error)
+ *error = LoadKey(blob);
+}
+
+Operation* DsaKey::CreateOperation(keymaster_purpose_t purpose, keymaster_digest_t digest,
+ keymaster_padding_t padding, keymaster_error_t* error) {
+ Operation* op;
+ switch (purpose) {
+ case KM_PURPOSE_SIGN:
+ op = new DsaSignOperation(purpose, logger_, digest, padding, dsa_key_.release());
+ break;
+ case KM_PURPOSE_VERIFY:
+ op = new DsaVerifyOperation(purpose, logger_, digest, padding, dsa_key_.release());
+ break;
+ default:
+ *error = KM_ERROR_UNIMPLEMENTED;
+ return NULL;
+ }
+ *error = op ? KM_ERROR_OK : KM_ERROR_MEMORY_ALLOCATION_FAILED;
+ return op;
+}
+
+bool DsaKey::EvpToInternal(const EVP_PKEY* pkey) {
+ dsa_key_.reset(EVP_PKEY_get1_DSA(const_cast<EVP_PKEY*>(pkey)));
+ return dsa_key_.get() != NULL;
+}
+
+bool DsaKey::InternalToEvp(EVP_PKEY* pkey) const {
+ return EVP_PKEY_set1_DSA(pkey, dsa_key_.get()) == 1;
+}
+
+} // namespace keymaster