[webcrypto] Check for empty key usages *after* key creation rather than before, to match the spec's…

components/webcrypto/algorithms/hmac.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <openssl/hmac.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 100 matching lines @@
 }
 
 class HmacImplementation : public AlgorithmImplementation {
  public:
   HmacImplementation() {}
 
   Status GenerateKey(const blink::WebCryptoAlgorithm& algorithm,
                      bool extractable,
                      blink::WebCryptoKeyUsageMask usages,
                      GenerateKeyResult* result) const override {
-    Status status = CheckSecretKeyCreationUsages(kAllKeyUsages, usages);
+    Status status = CheckKeyCreationUsages(kAllKeyUsages, usages);
     if (status.IsError())
       return status;
 
     const blink::WebCryptoHmacKeyGenParams* params =
         algorithm.hmacKeyGenParams();
 
     unsigned int keylen_bits = 0;
     if (params->hasLengthBits()) {
       keylen_bits = params->optionalLengthBits();
       // Zero-length HMAC keys are disallowed by the spec.
       if (keylen_bits == 0)
         return Status::ErrorGenerateHmacKeyLengthZero();
     } else {
       status = GetDigestBlockSizeBits(params->hash(), &keylen_bits);
       if (status.IsError())
         return status;
     }
 
     return GenerateWebCryptoSecretKey(blink::WebCryptoKeyAlgorithm::createHmac(
                                           params->hash().id(), keylen_bits),
                                       extractable, usages, keylen_bits, result);
   }
 
-  Status VerifyKeyUsagesBeforeImportKey(
-      blink::WebCryptoKeyFormat format,
-      blink::WebCryptoKeyUsageMask usages) const override {
+  Status ImportKey(blink::WebCryptoKeyFormat format,
+                   const CryptoData& key_data,
+                   const blink::WebCryptoAlgorithm& algorithm,
+                   bool extractable,
+                   blink::WebCryptoKeyUsageMask usages,
+                   blink::WebCryptoKey* key) const override {
     switch (format) {
       case blink::WebCryptoKeyFormatRaw:
+        return ImportKeyRaw(key_data, algorithm, extractable, usages, key);
       case blink::WebCryptoKeyFormatJwk:
-        return CheckSecretKeyCreationUsages(kAllKeyUsages, usages);
+        return ImportKeyJwk(key_data, algorithm, extractable, usages, key);
       default:
         return Status::ErrorUnsupportedImportKeyFormat();
     }
   }
 
+  Status ExportKey(blink::WebCryptoKeyFormat format,
+                   const blink::WebCryptoKey& key,
+                   std::vector<uint8_t>* buffer) const override {
+    switch (format) {
+      case blink::WebCryptoKeyFormatRaw:
+        return ExportKeyRaw(key, buffer);
+      case blink::WebCryptoKeyFormatJwk:
+        return ExportKeyJwk(key, buffer);
+      default:
+        return Status::ErrorUnsupportedExportKeyFormat();
+    }
+  }
+
   Status ImportKeyRaw(const CryptoData& key_data,
                       const blink::WebCryptoAlgorithm& algorithm,
                       bool extractable,
                       blink::WebCryptoKeyUsageMask usages,
-                      blink::WebCryptoKey* key) const override {
+                      blink::WebCryptoKey* key) const {
+    Status status = CheckKeyCreationUsages(kAllKeyUsages, usages);
+    if (status.IsError())
+      return status;
+
     const blink::WebCryptoHmacImportParams* params =
         algorithm.hmacImportParams();
 
     unsigned int keylen_bits = 0;
-    Status status = GetHmacImportKeyLengthBits(params, key_data.byte_length(),
-                                               &keylen_bits);
+    status = GetHmacImportKeyLengthBits(params, key_data.byte_length(),
+                                        &keylen_bits);
     if (status.IsError())
       return status;
 
     const blink::WebCryptoKeyAlgorithm key_algorithm =
         blink::WebCryptoKeyAlgorithm::createHmac(params->hash().id(),
                                                  keylen_bits);
 
     // If no bit truncation was requested, then done!
     if ((keylen_bits % 8) == 0) {
       return CreateWebCryptoSecretKey(key_data, key_algorithm, extractable,
                                       usages, key);
     }
 
     // Otherwise zero out the unused bits in the key data before importing.
     std::vector<uint8_t> modified_key_data(
         key_data.bytes(), key_data.bytes() + key_data.byte_length());
     TruncateToBitLength(keylen_bits, &modified_key_data);
     return CreateWebCryptoSecretKey(CryptoData(modified_key_data),
                                     key_algorithm, extractable, usages, key);
   }
 
   Status ImportKeyJwk(const CryptoData& key_data,
                       const blink::WebCryptoAlgorithm& algorithm,
                       bool extractable,
                       blink::WebCryptoKeyUsageMask usages,
-                      blink::WebCryptoKey* key) const override {
+                      blink::WebCryptoKey* key) const {
+    Status status = CheckKeyCreationUsages(kAllKeyUsages, usages);
+    if (status.IsError())
+      return status;
+
     const char* algorithm_name =
         GetJwkHmacAlgorithmName(algorithm.hmacImportParams()->hash().id());
     if (!algorithm_name)
       return Status::ErrorUnexpected();
 
     std::vector<uint8_t> raw_data;
     JwkReader jwk;
-    Status status = ReadSecretKeyNoExpectedAlgJwk(key_data, extractable, usages,
-                                                  &raw_data, &jwk);
+    status = ReadSecretKeyNoExpectedAlgJwk(key_data, extractable, usages,
+                                           &raw_data, &jwk);
     if (status.IsError())
       return status;
     status = jwk.VerifyAlg(algorithm_name);
     if (status.IsError())
       return status;
 
     return ImportKeyRaw(CryptoData(raw_data), algorithm, extractable, usages,
                         key);
   }
 
   Status ExportKeyRaw(const blink::WebCryptoKey& key,
-                      std::vector<uint8_t>* buffer) const override {
+                      std::vector<uint8_t>* buffer) const {
     *buffer = GetSymmetricKeyData(key);
     return Status::Success();
   }
 
   Status ExportKeyJwk(const blink::WebCryptoKey& key,
-                      std::vector<uint8_t>* buffer) const override {
+                      std::vector<uint8_t>* buffer) const {
     const std::vector<uint8_t>& raw_data = GetSymmetricKeyData(key);
 
     const char* algorithm_name =
         GetJwkHmacAlgorithmName(key.algorithm().hmacParams()->hash().id());
     if (!algorithm_name)
       return Status::ErrorUnexpected();
 
     WriteSecretKeyJwk(CryptoData(raw_data), algorithm_name, key.extractable(),
                       key.usages(), buffer);
 
@@ skipping 57 matching lines @@
   }
 };
 
 }  // namespace
 
 std::unique_ptr<AlgorithmImplementation> CreateHmacImplementation() {
   return base::WrapUnique(new HmacImplementation);
 }
 
 }  // namespace webcrypto