LibWeb: Implement AES-GCM.generateKey

Author: https://github.com/stelar7
Commit: https://github.com/LadybirdBrowser/ladybird/commit/171af8de333
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2085

Userland/Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp

@@ -2107,6 +2107,54 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::ArrayBuffer>> AesGcm::decrypt(Algorithm
     return JS::ArrayBuffer::create(m_realm, plaintext);
 }
 
+WebIDL::ExceptionOr<Variant<JS::NonnullGCPtr<CryptoKey>, JS::NonnullGCPtr<CryptoKeyPair>>> AesGcm::generate_key(AlgorithmParams const& params, bool extractable, Vector<Bindings::KeyUsage> const& key_usages)
+{
+    // 1. If usages contains any entry which is not one of "encrypt", "decrypt", "wrapKey" or "unwrapKey", then throw a SyntaxError.
+    for (auto const& usage : key_usages) {
+        if (usage != Bindings::KeyUsage::Encrypt && usage != Bindings::KeyUsage::Decrypt && usage != Bindings::KeyUsage::Wrapkey && usage != Bindings::KeyUsage::Unwrapkey) {
+            return WebIDL::SyntaxError::create(m_realm, MUST(String::formatted("Invalid key usage '{}'", idl_enum_to_string(usage))));
+        }
+    }
+
+    // 2. If the length member of normalizedAlgorithm is not equal to one of 128, 192 or 256, then throw an OperationError.
+    auto const& normalized_algorithm = static_cast<AesKeyGenParams const&>(params);
+    auto length = normalized_algorithm.length;
+    if (length != 128 && length != 192 && length != 256) {
+        return WebIDL::OperationError::create(m_realm, MUST(String::formatted("Cannot create AES-CTR key with unusual amount of {} bits", length)));
+    }
+
+    // 3. Generate an AES key of length equal to the length member of normalizedAlgorithm.
+    // 4. If the key generation step fails, then throw an OperationError.
+    auto key_buffer = TRY(generate_aes_key(m_realm->vm(), length / 8));
+
+    // 5. Let key be a new CryptoKey object representing the generated AES key.
+    auto key = CryptoKey::create(m_realm, CryptoKey::InternalKeyData { key_buffer });
+
+    // 6. Let algorithm be a new AesKeyAlgorithm.
+    auto algorithm = AesKeyAlgorithm::create(m_realm);
+
+    // 7. Set the name attribute of algorithm to "AES-GCM".
+    algorithm->set_name("AES-GCM"_string);
+
+    // 8. Set the length attribute of algorithm to equal the length member of normalizedAlgorithm.
+    algorithm->set_length(length);
+
+    // 9. Set the [[type]] internal slot of key to "secret".
+    key->set_type(Bindings::KeyType::Secret);
+
+    // 10. Set the [[algorithm]] internal slot of key to algorithm.
+    key->set_algorithm(algorithm);
+
+    // 11. Set the [[extractable]] internal slot of key to be extractable.
+    key->set_extractable(extractable);
+
+    // 12. Set the [[usages]] internal slot of key to be usages.
+    key->set_usages(key_usages);
+
+    // 13. Return key.
+    return { key };
+}
+
 // https://w3c.github.io/webcrypto/#hkdf-operations
 WebIDL::ExceptionOr<JS::NonnullGCPtr<CryptoKey>> HKDF::import_key(AlgorithmParams const&, Bindings::KeyFormat format, CryptoKey::InternalKeyData key_data, bool extractable, Vector<Bindings::KeyUsage> const& key_usages)
 {

Userland/Libraries/LibWeb/Crypto/CryptoAlgorithms.h

@@ -387,6 +387,7 @@ public:
     virtual WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Object>> export_key(Bindings::KeyFormat, JS::NonnullGCPtr<CryptoKey>) override;
     virtual WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::ArrayBuffer>> encrypt(AlgorithmParams const&, JS::NonnullGCPtr<CryptoKey>, ByteBuffer const&) override;
     virtual WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::ArrayBuffer>> decrypt(AlgorithmParams const&, JS::NonnullGCPtr<CryptoKey>, ByteBuffer const&) override;
+    virtual WebIDL::ExceptionOr<Variant<JS::NonnullGCPtr<CryptoKey>, JS::NonnullGCPtr<CryptoKeyPair>>> generate_key(AlgorithmParams const&, bool, Vector<Bindings::KeyUsage> const&) override;
 
     static NonnullOwnPtr<AlgorithmMethods> create(JS::Realm& realm) { return adopt_own(*new AesGcm(realm)); }
 

Userland/Libraries/LibWeb/Crypto/SubtleCrypto.cpp

@@ -788,6 +788,7 @@ SupportedAlgorithmsMap supported_algorithms()
     define_an_algorithm<AesGcm, AesDerivedKeyParams>("get key length"_string, "AES-GCM"_string);
     define_an_algorithm<AesGcm>("importKey"_string, "AES-GCM"_string);
     define_an_algorithm<AesGcm>("exportKey"_string, "AES-GCM"_string);
+    define_an_algorithm<AesGcm, AesKeyGenParams>("generateKey"_string, "AES-GCM"_string);
     define_an_algorithm<AesGcm, AesGcmParams>("encrypt"_string, "AES-GCM"_string);
     define_an_algorithm<AesGcm, AesGcmParams>("decrypt"_string, "AES-GCM"_string);