Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3276 insertions, 0 deletions

diff --git a/dom/crypto/WebCryptoTask.cpp b/dom/crypto/WebCryptoTask.cpp
new file mode 100644
index 0000000000..dfcd54f7be
--- /dev/null
+++ b/dom/crypto/WebCryptoTask.cpp
@@ -0,0 +1,3276 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "pk11pub.h"
+#include "cryptohi.h"
+#include "secerr.h"
+#include "nsNSSComponent.h"
+#include "nsProxyRelease.h"
+
+#include "jsapi.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/Utf8.h"
+#include "mozilla/dom/CryptoBuffer.h"
+#include "mozilla/dom/CryptoKey.h"
+#include "mozilla/dom/KeyAlgorithmProxy.h"
+#include "mozilla/dom/TypedArray.h"
+#include "mozilla/dom/WebCryptoCommon.h"
+#include "mozilla/dom/WebCryptoTask.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/RootedDictionary.h"
+
+// Template taken from security/nss/lib/util/templates.c
+// This (or SGN_EncodeDigestInfo) would ideally be exported
+// by NSS and until that happens we have to keep our own copy.
+const SEC_ASN1Template SGN_DigestInfoTemplate[] = {
+    {SEC_ASN1_SEQUENCE, 0, NULL, sizeof(SGNDigestInfo)},
+    {SEC_ASN1_INLINE, offsetof(SGNDigestInfo, digestAlgorithm),
+     SEC_ASN1_GET(SECOID_AlgorithmIDTemplate)},
+    {SEC_ASN1_OCTET_STRING, offsetof(SGNDigestInfo, digest)},
+    {
+        0,
+    }};
+
+namespace mozilla::dom {
+
+// Pre-defined identifiers for telemetry histograms
+
+enum TelemetryMethod {
+  TM_ENCRYPT = 0,
+  TM_DECRYPT = 1,
+  TM_SIGN = 2,
+  TM_VERIFY = 3,
+  TM_DIGEST = 4,
+  TM_GENERATEKEY = 5,
+  TM_DERIVEKEY = 6,
+  TM_DERIVEBITS = 7,
+  TM_IMPORTKEY = 8,
+  TM_EXPORTKEY = 9,
+  TM_WRAPKEY = 10,
+  TM_UNWRAPKEY = 11
+};
+
+enum TelemetryAlgorithm {
+  // Please make additions at the end of the list,
+  // to preserve comparability of histograms over time
+  TA_UNKNOWN = 0,
+  // encrypt / decrypt
+  TA_AES_CBC = 1,
+  TA_AES_CFB = 2,
+  TA_AES_CTR = 3,
+  TA_AES_GCM = 4,
+  TA_RSAES_PKCS1 = 5,  // NB: This algorithm has been removed
+  TA_RSA_OAEP = 6,
+  // sign/verify
+  TA_RSASSA_PKCS1 = 7,
+  TA_RSA_PSS = 8,
+  TA_HMAC_SHA_1 = 9,
+  TA_HMAC_SHA_224 = 10,
+  TA_HMAC_SHA_256 = 11,
+  TA_HMAC_SHA_384 = 12,
+  TA_HMAC_SHA_512 = 13,
+  // digest
+  TA_SHA_1 = 14,
+  TA_SHA_224 = 15,
+  TA_SHA_256 = 16,
+  TA_SHA_384 = 17,
+  TA_SHA_512 = 18,
+  // Later additions
+  TA_AES_KW = 19,
+  TA_ECDH = 20,
+  TA_PBKDF2 = 21,
+  TA_ECDSA = 22,
+  TA_HKDF = 23,
+  TA_DH = 24,
+};
+
+// Convenience functions for extracting / converting information
+
+// OOM-safe CryptoBuffer initialization, suitable for constructors
+#define ATTEMPT_BUFFER_INIT(dst, src)    \
+  if (!dst.Assign(src)) {                \
+    mEarlyRv = NS_ERROR_DOM_UNKNOWN_ERR; \
+    return;                              \
+  }
+
+// OOM-safe CryptoBuffer-to-SECItem copy, suitable for DoCrypto
+#define ATTEMPT_BUFFER_TO_SECITEM(arena, dst, src) \
+  if (!src.ToSECItem(arena, dst)) {                \
+    return NS_ERROR_DOM_UNKNOWN_ERR;               \
+  }
+
+// OOM-safe CryptoBuffer copy, suitable for DoCrypto
+#define ATTEMPT_BUFFER_ASSIGN(dst, src) \
+  if (!dst.Assign(src)) {               \
+    return NS_ERROR_DOM_UNKNOWN_ERR;    \
+  }
+
+// Safety check for algorithms that use keys, suitable for constructors
+#define CHECK_KEY_ALGORITHM(keyAlg, algName)         \
+  {                                                  \
+    if (!NORMALIZED_EQUALS(keyAlg.mName, algName)) { \
+      mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;    \
+      return;                                        \
+    }                                                \
+  }
+
+class ClearException {
+ public:
+  explicit ClearException(JSContext* aCx) : mCx(aCx) {}
+
+  ~ClearException() { JS_ClearPendingException(mCx); }
+
+ private:
+  JSContext* mCx;
+};
+
+template <class OOS>
+static nsresult GetAlgorithmName(JSContext* aCx, const OOS& aAlgorithm,
+                                 nsString& aName) {
+  ClearException ce(aCx);
+
+  if (aAlgorithm.IsString()) {
+    // If string, then treat as algorithm name
+    aName.Assign(aAlgorithm.GetAsString());
+  } else {
+    // Coerce to algorithm and extract name
+    JS::Rooted<JS::Value> value(aCx,
+                                JS::ObjectValue(*aAlgorithm.GetAsObject()));
+    Algorithm alg;
+
+    if (!alg.Init(aCx, value)) {
+      return NS_ERROR_DOM_SYNTAX_ERR;
+    }
+
+    aName = alg.mName;
+  }
+
+  if (!NormalizeToken(aName, aName)) {
+    return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+  }
+
+  return NS_OK;
+}
+
+template <class T, class OOS>
+static nsresult Coerce(JSContext* aCx, T& aTarget, const OOS& aAlgorithm) {
+  ClearException ce(aCx);
+
+  if (!aAlgorithm.IsObject()) {
+    return NS_ERROR_DOM_SYNTAX_ERR;
+  }
+
+  JS::Rooted<JS::Value> value(aCx, JS::ObjectValue(*aAlgorithm.GetAsObject()));
+  if (!aTarget.Init(aCx, value)) {
+    return NS_ERROR_DOM_SYNTAX_ERR;
+  }
+
+  return NS_OK;
+}
+
+inline size_t MapHashAlgorithmNameToBlockSize(const nsString& aName) {
+  if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA1) ||
+      aName.EqualsLiteral(WEBCRYPTO_ALG_SHA256)) {
+    return 512;
+  }
+
+  if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA384) ||
+      aName.EqualsLiteral(WEBCRYPTO_ALG_SHA512)) {
+    return 1024;
+  }
+
+  return 0;
+}
+
+inline nsresult GetKeyLengthForAlgorithm(JSContext* aCx,
+                                         const ObjectOrString& aAlgorithm,
+                                         size_t& aLength) {
+  aLength = 0;
+
+  // Extract algorithm name
+  nsString algName;
+  if (NS_FAILED(GetAlgorithmName(aCx, aAlgorithm, algName))) {
+    return NS_ERROR_DOM_SYNTAX_ERR;
+  }
+
+  // Read AES key length from given algorithm object.
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW)) {
+    RootedDictionary<AesDerivedKeyParams> params(aCx);
+    if (NS_FAILED(Coerce(aCx, params, aAlgorithm))) {
+      return NS_ERROR_DOM_SYNTAX_ERR;
+    }
+
+    if (params.mLength != 128 && params.mLength != 192 &&
+        params.mLength != 256) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    aLength = params.mLength;
+    return NS_OK;
+  }
+
+  // Read HMAC key length from given algorithm object or
+  // determine key length as the block size of the given hash.
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_HMAC)) {
+    RootedDictionary<HmacDerivedKeyParams> params(aCx);
+    if (NS_FAILED(Coerce(aCx, params, aAlgorithm))) {
+      return NS_ERROR_DOM_SYNTAX_ERR;
+    }
+
+    // Return the passed length, if any.
+    if (params.mLength.WasPassed()) {
+      aLength = params.mLength.Value();
+      return NS_OK;
+    }
+
+    nsString hashName;
+    if (NS_FAILED(GetAlgorithmName(aCx, params.mHash, hashName))) {
+      return NS_ERROR_DOM_SYNTAX_ERR;
+    }
+
+    // Return the given hash algorithm's block size as the key length.
+    size_t length = MapHashAlgorithmNameToBlockSize(hashName);
+    if (length == 0) {
+      return NS_ERROR_DOM_SYNTAX_ERR;
+    }
+
+    aLength = length;
+    return NS_OK;
+  }
+
+  return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+}
+
+inline bool MapOIDTagToNamedCurve(SECOidTag aOIDTag, nsString& aResult) {
+  switch (aOIDTag) {
+    case SEC_OID_SECG_EC_SECP256R1:
+      aResult.AssignLiteral(WEBCRYPTO_NAMED_CURVE_P256);
+      break;
+    case SEC_OID_SECG_EC_SECP384R1:
+      aResult.AssignLiteral(WEBCRYPTO_NAMED_CURVE_P384);
+      break;
+    case SEC_OID_SECG_EC_SECP521R1:
+      aResult.AssignLiteral(WEBCRYPTO_NAMED_CURVE_P521);
+      break;
+    default:
+      return false;
+  }
+
+  return true;
+}
+
+inline SECOidTag MapHashAlgorithmNameToOID(const nsString& aName) {
+  SECOidTag hashOID(SEC_OID_UNKNOWN);
+
+  if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA1)) {
+    hashOID = SEC_OID_SHA1;
+  } else if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA256)) {
+    hashOID = SEC_OID_SHA256;
+  } else if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA384)) {
+    hashOID = SEC_OID_SHA384;
+  } else if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA512)) {
+    hashOID = SEC_OID_SHA512;
+  }
+
+  return hashOID;
+}
+
+inline CK_MECHANISM_TYPE MapHashAlgorithmNameToMgfMechanism(
+    const nsString& aName) {
+  CK_MECHANISM_TYPE mech(UNKNOWN_CK_MECHANISM);
+
+  if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA1)) {
+    mech = CKG_MGF1_SHA1;
+  } else if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA256)) {
+    mech = CKG_MGF1_SHA256;
+  } else if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA384)) {
+    mech = CKG_MGF1_SHA384;
+  } else if (aName.EqualsLiteral(WEBCRYPTO_ALG_SHA512)) {
+    mech = CKG_MGF1_SHA512;
+  }
+
+  return mech;
+}
+
+// Implementation of WebCryptoTask methods
+
+void WebCryptoTask::DispatchWithPromise(Promise* aResultPromise) {
+  mResultPromise = aResultPromise;
+
+  // Fail if an error was set during the constructor
+  MAYBE_EARLY_FAIL(mEarlyRv)
+
+  // Perform pre-NSS operations, and fail if they fail
+  mEarlyRv = BeforeCrypto();
+  MAYBE_EARLY_FAIL(mEarlyRv)
+
+  // Skip dispatch if we're already done. Otherwise launch a CryptoTask
+  if (mEarlyComplete) {
+    CallCallback(mEarlyRv);
+    return;
+  }
+
+  // Store calling thread
+  mOriginalEventTarget = GetCurrentSerialEventTarget();
+
+  // If we are running on a worker thread we must hold the worker
+  // alive while we work on the thread pool.  Otherwise the worker
+  // private may get torn down before we dispatch back to complete
+  // the transaction.
+  if (!NS_IsMainThread()) {
+    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+    MOZ_ASSERT(workerPrivate);
+
+    RefPtr<StrongWorkerRef> workerRef =
+        StrongWorkerRef::Create(workerPrivate, "WebCryptoTask");
+    if (NS_WARN_IF(!workerRef)) {
+      mEarlyRv = NS_BINDING_ABORTED;
+    } else {
+      mWorkerRef = new ThreadSafeWorkerRef(workerRef);
+    }
+  }
+  MAYBE_EARLY_FAIL(mEarlyRv);
+
+  // dispatch to thread pool
+
+  if (!EnsureNSSInitializedChromeOrContent()) {
+    mEarlyRv = NS_ERROR_FAILURE;
+  }
+  MAYBE_EARLY_FAIL(mEarlyRv);
+
+  mEarlyRv = NS_DispatchBackgroundTask(this);
+  MAYBE_EARLY_FAIL(mEarlyRv)
+}
+
+NS_IMETHODIMP
+WebCryptoTask::Run() {
+  // Run heavy crypto operations on the thread pool, off the original thread.
+  if (!IsOnOriginalThread()) {
+    mRv = CalculateResult();
+
+    // Back to the original thread, i.e. continue below.
+    mOriginalEventTarget->Dispatch(this, NS_DISPATCH_NORMAL);
+    return NS_OK;
+  }
+
+  // We're now back on the calling thread.
+  CallCallback(mRv);
+
+  // Stop holding the worker thread alive now that the async work has
+  // been completed.
+  mWorkerRef = nullptr;
+
+  return NS_OK;
+}
+
+nsresult WebCryptoTask::Cancel() {
+  MOZ_ASSERT(IsOnOriginalThread());
+  FailWithError(NS_BINDING_ABORTED);
+  return NS_OK;
+}
+
+void WebCryptoTask::FailWithError(nsresult aRv) {
+  MOZ_ASSERT(IsOnOriginalThread());
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_RESOLVED, false);
+
+  // Blindly convert nsresult to DOMException
+  // Individual tasks must ensure they pass the right values
+  mResultPromise->MaybeReject(aRv);
+  // Manually release mResultPromise while we're on the main thread
+  mResultPromise = nullptr;
+  mWorkerRef = nullptr;
+  Cleanup();
+}
+
+nsresult WebCryptoTask::CalculateResult() {
+  MOZ_ASSERT(!IsOnOriginalThread());
+
+  return DoCrypto();
+}
+
+void WebCryptoTask::CallCallback(nsresult rv) {
+  MOZ_ASSERT(IsOnOriginalThread());
+  if (NS_FAILED(rv)) {
+    FailWithError(rv);
+    return;
+  }
+
+  nsresult rv2 = AfterCrypto();
+  if (NS_FAILED(rv2)) {
+    FailWithError(rv2);
+    return;
+  }
+
+  Resolve();
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_RESOLVED, true);
+
+  // Manually release mResultPromise while we're on the main thread
+  mResultPromise = nullptr;
+  Cleanup();
+}
+
+// Some generic utility classes
+
+class FailureTask : public WebCryptoTask {
+ public:
+  explicit FailureTask(nsresult aRv) { mEarlyRv = aRv; }
+};
+
+class ReturnArrayBufferViewTask : public WebCryptoTask {
+ protected:
+  CryptoBuffer mResult;
+
+ private:
+  // Returns mResult as an ArrayBufferView, or an error
+  virtual void Resolve() override {
+    TypedArrayCreator<ArrayBuffer> ret(mResult);
+    mResultPromise->MaybeResolve(ret);
+  }
+};
+
+class DeferredData {
+ public:
+  template <class T>
+  void SetData(const T& aData) {
+    mDataIsSet = mData.Assign(aData);
+  }
+
+ protected:
+  DeferredData() : mDataIsSet(false) {}
+
+  CryptoBuffer mData;
+  bool mDataIsSet;
+};
+
+class AesTask : public ReturnArrayBufferViewTask, public DeferredData {
+ public:
+  AesTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+          bool aEncrypt)
+      : mMechanism(CKM_INVALID_MECHANISM),
+        mTagLength(0),
+        mCounterLength(0),
+        mEncrypt(aEncrypt) {
+    Init(aCx, aAlgorithm, aKey, aEncrypt);
+  }
+
+  AesTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+          const CryptoOperationData& aData, bool aEncrypt)
+      : mMechanism(CKM_INVALID_MECHANISM),
+        mTagLength(0),
+        mCounterLength(0),
+        mEncrypt(aEncrypt) {
+    Init(aCx, aAlgorithm, aKey, aEncrypt);
+    SetData(aData);
+  }
+
+  void Init(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            bool aEncrypt) {
+    nsString algName;
+    mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, algName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    if (!mSymKey.Assign(aKey.GetSymKey())) {
+      mEarlyRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+
+    // Check that we got a reasonable key
+    if ((mSymKey.Length() != 16) && (mSymKey.Length() != 24) &&
+        (mSymKey.Length() != 32)) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+
+    // Cache parameters depending on the specific algorithm
+    TelemetryAlgorithm telemetryAlg;
+    if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC)) {
+      CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_AES_CBC);
+
+      mMechanism = CKM_AES_CBC_PAD;
+      telemetryAlg = TA_AES_CBC;
+      RootedDictionary<AesCbcParams> params(aCx);
+      nsresult rv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(rv)) {
+        mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+        return;
+      }
+
+      ATTEMPT_BUFFER_INIT(mIv, params.mIv)
+      if (mIv.Length() != 16) {
+        mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+        return;
+      }
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR)) {
+      CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_AES_CTR);
+
+      mMechanism = CKM_AES_CTR;
+      telemetryAlg = TA_AES_CTR;
+      RootedDictionary<AesCtrParams> params(aCx);
+      nsresult rv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(rv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      ATTEMPT_BUFFER_INIT(mIv, params.mCounter)
+      if (mIv.Length() != 16) {
+        mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+        return;
+      }
+
+      mCounterLength = params.mLength;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM)) {
+      CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_AES_GCM);
+
+      mMechanism = CKM_AES_GCM;
+      telemetryAlg = TA_AES_GCM;
+      RootedDictionary<AesGcmParams> params(aCx);
+      nsresult rv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(rv)) {
+        mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+        return;
+      }
+
+      ATTEMPT_BUFFER_INIT(mIv, params.mIv)
+
+      if (params.mAdditionalData.WasPassed()) {
+        ATTEMPT_BUFFER_INIT(mAad, params.mAdditionalData.Value())
+      }
+
+      // 32, 64, 96, 104, 112, 120 or 128
+      mTagLength = 128;
+      if (params.mTagLength.WasPassed()) {
+        mTagLength = params.mTagLength.Value();
+        if ((mTagLength > 128) ||
+            !(mTagLength == 32 || mTagLength == 64 ||
+              (mTagLength >= 96 && mTagLength % 8 == 0))) {
+          mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+          return;
+        }
+      }
+    } else {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, telemetryAlg);
+  }
+
+ private:
+  CK_MECHANISM_TYPE mMechanism;
+  CryptoBuffer mSymKey;
+  CryptoBuffer mIv;   // Initialization vector
+  CryptoBuffer mAad;  // Additional Authenticated Data
+  uint8_t mTagLength;
+  uint8_t mCounterLength;
+  bool mEncrypt;
+
+  virtual nsresult DoCrypto() override {
+    nsresult rv;
+
+    if (!mDataIsSet) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    UniquePLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
+    if (!arena) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Construct the parameters object depending on algorithm
+    SECItem param = {siBuffer, nullptr, 0};
+    CK_AES_CTR_PARAMS ctrParams;
+    CK_GCM_PARAMS gcmParams;
+    switch (mMechanism) {
+      case CKM_AES_CBC_PAD:
+        ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &param, mIv);
+        break;
+      case CKM_AES_CTR:
+        ctrParams.ulCounterBits = mCounterLength;
+        MOZ_ASSERT(mIv.Length() == 16);
+        memcpy(&ctrParams.cb, mIv.Elements(), 16);
+        param.type = siBuffer;
+        param.data = (unsigned char*)&ctrParams;
+        param.len = sizeof(ctrParams);
+        break;
+      case CKM_AES_GCM:
+        gcmParams.pIv = mIv.Elements();
+        gcmParams.ulIvLen = mIv.Length();
+        gcmParams.ulIvBits = gcmParams.ulIvLen * 8;
+        gcmParams.pAAD = mAad.Elements();
+        gcmParams.ulAADLen = mAad.Length();
+        gcmParams.ulTagBits = mTagLength;
+        param.type = siBuffer;
+        param.data = (unsigned char*)&gcmParams;
+        param.len = sizeof(gcmParams);
+        break;
+      default:
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+    }
+
+    // Import the key
+    SECItem keyItem = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &keyItem, mSymKey);
+    UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+    MOZ_ASSERT(slot.get());
+    UniquePK11SymKey symKey(PK11_ImportSymKey(slot.get(), mMechanism,
+                                              PK11_OriginUnwrap, CKA_ENCRYPT,
+                                              &keyItem, nullptr));
+    if (!symKey) {
+      return NS_ERROR_DOM_INVALID_ACCESS_ERR;
+    }
+
+    // Check whether the integer addition would overflow.
+    if (std::numeric_limits<CryptoBuffer::size_type>::max() - 16 <
+        mData.Length()) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    // Initialize the output buffer (enough space for padding / a full tag)
+    if (!mResult.SetLength(mData.Length() + 16, fallible)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    uint32_t outLen = 0;
+
+    // Perform the encryption/decryption
+    if (mEncrypt) {
+      rv = MapSECStatus(PK11_Encrypt(
+          symKey.get(), mMechanism, &param, mResult.Elements(), &outLen,
+          mResult.Length(), mData.Elements(), mData.Length()));
+    } else {
+      rv = MapSECStatus(PK11_Decrypt(
+          symKey.get(), mMechanism, &param, mResult.Elements(), &outLen,
+          mResult.Length(), mData.Elements(), mData.Length()));
+    }
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+
+    mResult.TruncateLength(outLen);
+    return rv;
+  }
+};
+
+// This class looks like an encrypt/decrypt task, like AesTask,
+// but it is only exposed to wrapKey/unwrapKey, not encrypt/decrypt
+class AesKwTask : public ReturnArrayBufferViewTask, public DeferredData {
+ public:
+  AesKwTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            bool aEncrypt)
+      : mMechanism(CKM_NSS_AES_KEY_WRAP), mEncrypt(aEncrypt) {
+    Init(aCx, aAlgorithm, aKey, aEncrypt);
+  }
+
+  AesKwTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            const CryptoOperationData& aData, bool aEncrypt)
+      : mMechanism(CKM_NSS_AES_KEY_WRAP), mEncrypt(aEncrypt) {
+    Init(aCx, aAlgorithm, aKey, aEncrypt);
+    SetData(aData);
+  }
+
+  void Init(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            bool aEncrypt) {
+    CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_AES_KW);
+
+    nsString algName;
+    mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, algName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    if (!mSymKey.Assign(aKey.GetSymKey())) {
+      mEarlyRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+
+    // Check that we got a reasonable key
+    if ((mSymKey.Length() != 16) && (mSymKey.Length() != 24) &&
+        (mSymKey.Length() != 32)) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_AES_KW);
+  }
+
+ private:
+  CK_MECHANISM_TYPE mMechanism;
+  CryptoBuffer mSymKey;
+  bool mEncrypt;
+
+  virtual nsresult DoCrypto() override {
+    nsresult rv;
+
+    if (!mDataIsSet) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Check that the input is a multiple of 64 bits long
+    if (mData.Length() == 0 || mData.Length() % 8 != 0) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    UniquePLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
+    if (!arena) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Import the key
+    SECItem keyItem = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &keyItem, mSymKey);
+    UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+    MOZ_ASSERT(slot.get());
+    UniquePK11SymKey symKey(PK11_ImportSymKey(slot.get(), mMechanism,
+                                              PK11_OriginUnwrap, CKA_WRAP,
+                                              &keyItem, nullptr));
+    if (!symKey) {
+      return NS_ERROR_DOM_INVALID_ACCESS_ERR;
+    }
+
+    // Import the data to a SECItem
+    SECItem dataItem = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &dataItem, mData);
+
+    // Parameters for the fake keys
+    CK_MECHANISM_TYPE fakeMechanism = CKM_SHA_1_HMAC;
+    CK_ATTRIBUTE_TYPE fakeOperation = CKA_SIGN;
+
+    if (mEncrypt) {
+      // Import the data into a fake PK11SymKey structure
+      UniquePK11SymKey keyToWrap(
+          PK11_ImportSymKey(slot.get(), fakeMechanism, PK11_OriginUnwrap,
+                            fakeOperation, &dataItem, nullptr));
+      if (!keyToWrap) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      // Encrypt and return the wrapped key
+      // AES-KW encryption results in a wrapped key 64 bits longer
+      if (!mResult.SetLength(mData.Length() + 8, fallible)) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+      SECItem resultItem = {siBuffer, mResult.Elements(),
+                            (unsigned int)mResult.Length()};
+      rv = MapSECStatus(PK11_WrapSymKey(mMechanism, nullptr, symKey.get(),
+                                        keyToWrap.get(), &resultItem));
+      NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+    } else {
+      // Decrypt the ciphertext into a temporary PK11SymKey
+      // Unwrapped key should be 64 bits shorter
+      int keySize = mData.Length() - 8;
+      UniquePK11SymKey unwrappedKey(
+          PK11_UnwrapSymKey(symKey.get(), mMechanism, nullptr, &dataItem,
+                            fakeMechanism, fakeOperation, keySize));
+      if (!unwrappedKey) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      // Export the key to get the cleartext
+      rv = MapSECStatus(PK11_ExtractKeyValue(unwrappedKey.get()));
+      if (NS_FAILED(rv)) {
+        return NS_ERROR_DOM_UNKNOWN_ERR;
+      }
+      ATTEMPT_BUFFER_ASSIGN(mResult, PK11_GetKeyData(unwrappedKey.get()));
+    }
+
+    return rv;
+  }
+};
+
+class RsaOaepTask : public ReturnArrayBufferViewTask, public DeferredData {
+ public:
+  RsaOaepTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+              bool aEncrypt)
+      : mPrivKey(aKey.GetPrivateKey()),
+        mPubKey(aKey.GetPublicKey()),
+        mEncrypt(aEncrypt) {
+    Init(aCx, aAlgorithm, aKey, aEncrypt);
+  }
+
+  RsaOaepTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+              const CryptoOperationData& aData, bool aEncrypt)
+      : mPrivKey(aKey.GetPrivateKey()),
+        mPubKey(aKey.GetPublicKey()),
+        mEncrypt(aEncrypt) {
+    Init(aCx, aAlgorithm, aKey, aEncrypt);
+    SetData(aData);
+  }
+
+  void Init(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            bool aEncrypt) {
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_RSA_OAEP);
+
+    CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_RSA_OAEP);
+
+    if (mEncrypt) {
+      if (!mPubKey) {
+        mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+        return;
+      }
+      mStrength = SECKEY_PublicKeyStrength(mPubKey.get());
+    } else {
+      if (!mPrivKey) {
+        mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+        return;
+      }
+      mStrength = PK11_GetPrivateModulusLen(mPrivKey.get());
+    }
+
+    // The algorithm could just be given as a string
+    // in which case there would be no label specified.
+    if (!aAlgorithm.IsString()) {
+      RootedDictionary<RsaOaepParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      if (params.mLabel.WasPassed()) {
+        ATTEMPT_BUFFER_INIT(mLabel, params.mLabel.Value());
+      }
+    }
+    // Otherwise mLabel remains the empty octet string, as intended
+
+    KeyAlgorithm& hashAlg = aKey.Algorithm().mRsa.mHash;
+    mHashMechanism = KeyAlgorithmProxy::GetMechanism(hashAlg);
+    mMgfMechanism = MapHashAlgorithmNameToMgfMechanism(hashAlg.mName);
+
+    // Check we found appropriate mechanisms.
+    if (mHashMechanism == UNKNOWN_CK_MECHANISM ||
+        mMgfMechanism == UNKNOWN_CK_MECHANISM) {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+  }
+
+ private:
+  CK_MECHANISM_TYPE mHashMechanism;
+  CK_MECHANISM_TYPE mMgfMechanism;
+  UniqueSECKEYPrivateKey mPrivKey;
+  UniqueSECKEYPublicKey mPubKey;
+  CryptoBuffer mLabel;
+  uint32_t mStrength;
+  bool mEncrypt;
+
+  virtual nsresult DoCrypto() override {
+    nsresult rv;
+
+    if (!mDataIsSet) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Ciphertext is an integer mod the modulus, so it will be
+    // no longer than mStrength octets
+    if (!mResult.SetLength(mStrength, fallible)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    CK_RSA_PKCS_OAEP_PARAMS oaepParams;
+    oaepParams.source = CKZ_DATA_SPECIFIED;
+
+    oaepParams.pSourceData = mLabel.Length() ? mLabel.Elements() : nullptr;
+    oaepParams.ulSourceDataLen = mLabel.Length();
+
+    oaepParams.mgf = mMgfMechanism;
+    oaepParams.hashAlg = mHashMechanism;
+
+    SECItem param;
+    param.type = siBuffer;
+    param.data = (unsigned char*)&oaepParams;
+    param.len = sizeof(oaepParams);
+
+    uint32_t outLen = 0;
+    if (mEncrypt) {
+      // PK11_PubEncrypt() checks the plaintext's length and fails if it is too
+      // long to encrypt, i.e. if it is longer than (k - 2hLen - 2) with 'k'
+      // being the length in octets of the RSA modulus n and 'hLen' being the
+      // output length in octets of the chosen hash function.
+      // <https://tools.ietf.org/html/rfc3447#section-7.1>
+      rv = MapSECStatus(PK11_PubEncrypt(
+          mPubKey.get(), CKM_RSA_PKCS_OAEP, &param, mResult.Elements(), &outLen,
+          mResult.Length(), mData.Elements(), mData.Length(), nullptr));
+    } else {
+      rv = MapSECStatus(PK11_PrivDecrypt(
+          mPrivKey.get(), CKM_RSA_PKCS_OAEP, &param, mResult.Elements(),
+          &outLen, mResult.Length(), mData.Elements(), mData.Length()));
+    }
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+
+    mResult.TruncateLength(outLen);
+    return NS_OK;
+  }
+};
+
+class HmacTask : public WebCryptoTask {
+ public:
+  HmacTask(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+           const CryptoOperationData& aSignature,
+           const CryptoOperationData& aData, bool aSign)
+      : mMechanism(aKey.Algorithm().Mechanism()), mSign(aSign) {
+    CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_HMAC);
+
+    ATTEMPT_BUFFER_INIT(mData, aData);
+    if (!aSign) {
+      ATTEMPT_BUFFER_INIT(mSignature, aSignature);
+    }
+
+    if (!mSymKey.Assign(aKey.GetSymKey())) {
+      mEarlyRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+
+    // Check that we got a symmetric key
+    if (mSymKey.Length() == 0) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+
+    TelemetryAlgorithm telemetryAlg;
+    switch (mMechanism) {
+      case CKM_SHA_1_HMAC:
+        telemetryAlg = TA_HMAC_SHA_1;
+        break;
+      case CKM_SHA224_HMAC:
+        telemetryAlg = TA_HMAC_SHA_224;
+        break;
+      case CKM_SHA256_HMAC:
+        telemetryAlg = TA_HMAC_SHA_256;
+        break;
+      case CKM_SHA384_HMAC:
+        telemetryAlg = TA_HMAC_SHA_384;
+        break;
+      case CKM_SHA512_HMAC:
+        telemetryAlg = TA_HMAC_SHA_512;
+        break;
+      default:
+        telemetryAlg = TA_UNKNOWN;
+    }
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, telemetryAlg);
+  }
+
+ private:
+  CK_MECHANISM_TYPE mMechanism;
+  CryptoBuffer mSymKey;
+  CryptoBuffer mData;
+  CryptoBuffer mSignature;
+  CryptoBuffer mResult;
+  bool mSign;
+
+  virtual nsresult DoCrypto() override {
+    // Initialize the output buffer
+    if (!mResult.SetLength(HASH_LENGTH_MAX, fallible)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    UniquePLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
+    if (!arena) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Import the key
+    uint32_t outLen;
+    SECItem keyItem = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &keyItem, mSymKey);
+    UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+    MOZ_ASSERT(slot.get());
+    UniquePK11SymKey symKey(PK11_ImportSymKey(slot.get(), mMechanism,
+                                              PK11_OriginUnwrap, CKA_SIGN,
+                                              &keyItem, nullptr));
+    if (!symKey) {
+      return NS_ERROR_DOM_INVALID_ACCESS_ERR;
+    }
+
+    // Compute the MAC
+    SECItem param = {siBuffer, nullptr, 0};
+    UniquePK11Context ctx(
+        PK11_CreateContextBySymKey(mMechanism, CKA_SIGN, symKey.get(), &param));
+    if (!ctx.get()) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+    nsresult rv = MapSECStatus(PK11_DigestBegin(ctx.get()));
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+    rv = MapSECStatus(
+        PK11_DigestOp(ctx.get(), mData.Elements(), mData.Length()));
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+    rv = MapSECStatus(PK11_DigestFinal(ctx.get(), mResult.Elements(), &outLen,
+                                       mResult.Length()));
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+
+    mResult.TruncateLength(outLen);
+    return rv;
+  }
+
+  // Returns mResult as an ArrayBufferView, or an error
+  virtual void Resolve() override {
+    if (mSign) {
+      // Return the computed MAC
+      TypedArrayCreator<ArrayBuffer> ret(mResult);
+      mResultPromise->MaybeResolve(ret);
+    } else {
+      // Compare the MAC to the provided signature
+      // No truncation allowed
+      bool equal = (mResult.Length() == mSignature.Length());
+      if (equal) {
+        int cmp = NSS_SecureMemcmp(mSignature.Elements(), mResult.Elements(),
+                                   mSignature.Length());
+        equal = (cmp == 0);
+      }
+      mResultPromise->MaybeResolve(equal);
+    }
+  }
+};
+
+class AsymmetricSignVerifyTask : public WebCryptoTask {
+ public:
+  AsymmetricSignVerifyTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                           CryptoKey& aKey,
+                           const CryptoOperationData& aSignature,
+                           const CryptoOperationData& aData, bool aSign)
+      : mOidTag(SEC_OID_UNKNOWN),
+        mHashMechanism(UNKNOWN_CK_MECHANISM),
+        mMgfMechanism(UNKNOWN_CK_MECHANISM),
+        mPrivKey(aKey.GetPrivateKey()),
+        mPubKey(aKey.GetPublicKey()),
+        mSaltLength(0),
+        mSign(aSign),
+        mVerified(false),
+        mAlgorithm(Algorithm::UNKNOWN) {
+    ATTEMPT_BUFFER_INIT(mData, aData);
+    if (!aSign) {
+      ATTEMPT_BUFFER_INIT(mSignature, aSignature);
+    }
+
+    nsString algName;
+    nsString hashAlgName;
+    mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, algName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    if (algName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1)) {
+      mAlgorithm = Algorithm::RSA_PKCS1;
+      Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_RSASSA_PKCS1);
+      CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_RSASSA_PKCS1);
+      hashAlgName = aKey.Algorithm().mRsa.mHash.mName;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS)) {
+      mAlgorithm = Algorithm::RSA_PSS;
+      Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_RSA_PSS);
+      CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_RSA_PSS);
+
+      KeyAlgorithm& hashAlg = aKey.Algorithm().mRsa.mHash;
+      hashAlgName = hashAlg.mName;
+      mHashMechanism = KeyAlgorithmProxy::GetMechanism(hashAlg);
+      mMgfMechanism = MapHashAlgorithmNameToMgfMechanism(hashAlgName);
+
+      // Check we found appropriate mechanisms.
+      if (mHashMechanism == UNKNOWN_CK_MECHANISM ||
+          mMgfMechanism == UNKNOWN_CK_MECHANISM) {
+        mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        return;
+      }
+
+      RootedDictionary<RsaPssParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      mSaltLength = params.mSaltLength;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+      mAlgorithm = Algorithm::ECDSA;
+      Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_ECDSA);
+      CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_ECDSA);
+
+      // For ECDSA, the hash name comes from the algorithm parameter
+      RootedDictionary<EcdsaParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      mEarlyRv = GetAlgorithmName(aCx, params.mHash, hashAlgName);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+    } else {
+      // This shouldn't happen; CreateSignVerifyTask shouldn't create
+      // one of these unless it's for the above algorithms.
+      MOZ_ASSERT(false);
+    }
+
+    // Must have a valid algorithm by now.
+    MOZ_ASSERT(mAlgorithm != Algorithm::UNKNOWN);
+
+    // Determine hash algorithm to use.
+    mOidTag = MapHashAlgorithmNameToOID(hashAlgName);
+    if (mOidTag == SEC_OID_UNKNOWN) {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+
+    // Check that we have the appropriate key
+    if ((mSign && !mPrivKey) || (!mSign && !mPubKey)) {
+      mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+      return;
+    }
+  }
+
+ private:
+  SECOidTag mOidTag;
+  CK_MECHANISM_TYPE mHashMechanism;
+  CK_MECHANISM_TYPE mMgfMechanism;
+  UniqueSECKEYPrivateKey mPrivKey;
+  UniqueSECKEYPublicKey mPubKey;
+  CryptoBuffer mSignature;
+  CryptoBuffer mData;
+  uint32_t mSaltLength;
+  bool mSign;
+  bool mVerified;
+
+  // The signature algorithm to use.
+  enum class Algorithm : uint8_t { ECDSA, RSA_PKCS1, RSA_PSS, UNKNOWN };
+  Algorithm mAlgorithm;
+
+  virtual nsresult DoCrypto() override {
+    SECStatus rv;
+    UniqueSECItem hash(
+        ::SECITEM_AllocItem(nullptr, nullptr, HASH_ResultLenByOidTag(mOidTag)));
+    if (!hash) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Compute digest over given data.
+    rv = PK11_HashBuf(mOidTag, hash->data, mData.Elements(), mData.Length());
+    NS_ENSURE_SUCCESS(MapSECStatus(rv), NS_ERROR_DOM_OPERATION_ERR);
+
+    // Wrap hash in a digest info template (RSA-PKCS1 only).
+    if (mAlgorithm == Algorithm::RSA_PKCS1) {
+      UniqueSGNDigestInfo di(
+          SGN_CreateDigestInfo(mOidTag, hash->data, hash->len));
+      if (!di) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      // Reuse |hash|.
+      SECITEM_FreeItem(hash.get(), false);
+      if (!SEC_ASN1EncodeItem(nullptr, hash.get(), di.get(),
+                              SGN_DigestInfoTemplate)) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+    }
+
+    SECItem* params = nullptr;
+    CK_MECHANISM_TYPE mech =
+        PK11_MapSignKeyType((mSign ? mPrivKey->keyType : mPubKey->keyType));
+
+    CK_RSA_PKCS_PSS_PARAMS rsaPssParams;
+    SECItem rsaPssParamsItem = {
+        siBuffer,
+    };
+
+    // Set up parameters for RSA-PSS.
+    if (mAlgorithm == Algorithm::RSA_PSS) {
+      rsaPssParams.hashAlg = mHashMechanism;
+      rsaPssParams.mgf = mMgfMechanism;
+      rsaPssParams.sLen = mSaltLength;
+
+      rsaPssParamsItem.data = (unsigned char*)&rsaPssParams;
+      rsaPssParamsItem.len = sizeof(rsaPssParams);
+      params = &rsaPssParamsItem;
+
+      mech = CKM_RSA_PKCS_PSS;
+    }
+
+    // Allocate SECItem to hold the signature.
+    uint32_t len = mSign ? PK11_SignatureLen(mPrivKey.get()) : 0;
+    UniqueSECItem sig(::SECITEM_AllocItem(nullptr, nullptr, len));
+    if (!sig) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    if (mSign) {
+      // Sign the hash.
+      rv = PK11_SignWithMechanism(mPrivKey.get(), mech, params, sig.get(),
+                                  hash.get());
+      NS_ENSURE_SUCCESS(MapSECStatus(rv), NS_ERROR_DOM_OPERATION_ERR);
+      ATTEMPT_BUFFER_ASSIGN(mSignature, sig.get());
+    } else {
+      // Copy the given signature to the SECItem.
+      if (!mSignature.ToSECItem(nullptr, sig.get())) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      // Verify the signature.
+      rv = PK11_VerifyWithMechanism(mPubKey.get(), mech, params, sig.get(),
+                                    hash.get(), nullptr);
+      mVerified = NS_SUCCEEDED(MapSECStatus(rv));
+    }
+
+    return NS_OK;
+  }
+
+  virtual void Resolve() override {
+    if (mSign) {
+      TypedArrayCreator<ArrayBuffer> ret(mSignature);
+      mResultPromise->MaybeResolve(ret);
+    } else {
+      mResultPromise->MaybeResolve(mVerified);
+    }
+  }
+};
+
+class DigestTask : public ReturnArrayBufferViewTask {
+ public:
+  DigestTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+             const CryptoOperationData& aData) {
+    ATTEMPT_BUFFER_INIT(mData, aData);
+
+    nsString algName;
+    mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, algName);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    TelemetryAlgorithm telemetryAlg;
+    if (algName.EqualsLiteral(WEBCRYPTO_ALG_SHA1)) {
+      telemetryAlg = TA_SHA_1;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_SHA256)) {
+      telemetryAlg = TA_SHA_224;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_SHA384)) {
+      telemetryAlg = TA_SHA_256;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_SHA512)) {
+      telemetryAlg = TA_SHA_384;
+    } else {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, telemetryAlg);
+    mOidTag = MapHashAlgorithmNameToOID(algName);
+  }
+
+ private:
+  SECOidTag mOidTag;
+  CryptoBuffer mData;
+
+  virtual nsresult DoCrypto() override {
+    // Resize the result buffer
+    uint32_t hashLen = HASH_ResultLenByOidTag(mOidTag);
+    if (!mResult.SetLength(hashLen, fallible)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    // Compute the hash
+    nsresult rv = MapSECStatus(PK11_HashBuf(mOidTag, mResult.Elements(),
+                                            mData.Elements(), mData.Length()));
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    return rv;
+  }
+};
+
+class ImportKeyTask : public WebCryptoTask {
+ public:
+  void Init(nsIGlobalObject* aGlobal, JSContext* aCx, const nsAString& aFormat,
+            const ObjectOrString& aAlgorithm, bool aExtractable,
+            const Sequence<nsString>& aKeyUsages) {
+    mFormat = aFormat;
+    mDataIsSet = false;
+    mDataIsJwk = false;
+
+    // This stuff pretty much always happens, so we'll do it here
+    mKey = new CryptoKey(aGlobal);
+    mKey->SetExtractable(aExtractable);
+    mKey->ClearUsages();
+    for (uint32_t i = 0; i < aKeyUsages.Length(); ++i) {
+      mEarlyRv = mKey->AddUsage(aKeyUsages[i]);
+      if (NS_FAILED(mEarlyRv)) {
+        return;
+      }
+    }
+
+    mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, mAlgName);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+  }
+
+  static bool JwkCompatible(const JsonWebKey& aJwk, const CryptoKey* aKey) {
+    // Check 'ext'
+    if (aKey->Extractable() && aJwk.mExt.WasPassed() && !aJwk.mExt.Value()) {
+      return false;
+    }
+
+    // Check 'alg'
+    if (aJwk.mAlg.WasPassed() &&
+        aJwk.mAlg.Value() != aKey->Algorithm().JwkAlg()) {
+      return false;
+    }
+
+    // Check 'key_ops'
+    if (aJwk.mKey_ops.WasPassed()) {
+      nsTArray<nsString> usages;
+      aKey->GetUsages(usages);
+      for (size_t i = 0; i < usages.Length(); ++i) {
+        if (!aJwk.mKey_ops.Value().Contains(usages[i])) {
+          return false;
+        }
+      }
+    }
+
+    // Individual algorithms may still have to check 'use'
+    return true;
+  }
+
+  void SetKeyData(JSContext* aCx, JS::Handle<JSObject*> aKeyData) {
+    mDataIsJwk = false;
+
+    // Try ArrayBuffer
+    RootedSpiderMonkeyInterface<ArrayBuffer> ab(aCx);
+    if (ab.Init(aKeyData)) {
+      if (!mKeyData.Assign(ab)) {
+        mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      }
+      return;
+    }
+
+    // Try ArrayBufferView
+    RootedSpiderMonkeyInterface<ArrayBufferView> abv(aCx);
+    if (abv.Init(aKeyData)) {
+      if (!mKeyData.Assign(abv)) {
+        mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      }
+      return;
+    }
+
+    // Try JWK
+    ClearException ce(aCx);
+    JS::Rooted<JS::Value> value(aCx, JS::ObjectValue(*aKeyData));
+    if (!mJwk.Init(aCx, value)) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+
+    mDataIsJwk = true;
+  }
+
+  void SetKeyDataMaybeParseJWK(const CryptoBuffer& aKeyData) {
+    if (!mKeyData.Assign(aKeyData)) {
+      mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      return;
+    }
+
+    mDataIsJwk = false;
+
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      nsDependentCSubstring utf8(
+          (const char*)mKeyData.Elements(),
+          (const char*)(mKeyData.Elements() + mKeyData.Length()));
+      if (!IsUtf8(utf8)) {
+        mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+        return;
+      }
+
+      nsString json = NS_ConvertUTF8toUTF16(utf8);
+      if (!mJwk.Init(json)) {
+        mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+        return;
+      }
+
+      mDataIsJwk = true;
+    }
+  }
+
+  void SetRawKeyData(const CryptoBuffer& aKeyData) {
+    if (!mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW)) {
+      mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      return;
+    }
+
+    if (!mKeyData.Assign(aKeyData)) {
+      mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      return;
+    }
+
+    mDataIsJwk = false;
+  }
+
+ protected:
+  nsString mFormat;
+  RefPtr<CryptoKey> mKey;
+  CryptoBuffer mKeyData;
+  bool mDataIsSet;
+  bool mDataIsJwk;
+  JsonWebKey mJwk;
+  nsString mAlgName;
+
+ private:
+  virtual void Resolve() override { mResultPromise->MaybeResolve(mKey); }
+
+  virtual void Cleanup() override { mKey = nullptr; }
+};
+
+class ImportSymmetricKeyTask : public ImportKeyTask {
+ public:
+  ImportSymmetricKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                         const nsAString& aFormat,
+                         const ObjectOrString& aAlgorithm, bool aExtractable,
+                         const Sequence<nsString>& aKeyUsages) {
+    Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable, aKeyUsages);
+  }
+
+  ImportSymmetricKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                         const nsAString& aFormat,
+                         const JS::Handle<JSObject*> aKeyData,
+                         const ObjectOrString& aAlgorithm, bool aExtractable,
+                         const Sequence<nsString>& aKeyUsages) {
+    Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable, aKeyUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    SetKeyData(aCx, aKeyData);
+    NS_ENSURE_SUCCESS_VOID(mEarlyRv);
+    if (mDataIsJwk && !mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+  }
+
+  void Init(nsIGlobalObject* aGlobal, JSContext* aCx, const nsAString& aFormat,
+            const ObjectOrString& aAlgorithm, bool aExtractable,
+            const Sequence<nsString>& aKeyUsages) {
+    ImportKeyTask::Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable,
+                        aKeyUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    // This task only supports raw and JWK format.
+    if (!mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK) &&
+        !mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW)) {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+
+    // If this is an HMAC key, import the hash name
+    if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_HMAC)) {
+      RootedDictionary<HmacImportParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+      mEarlyRv = GetAlgorithmName(aCx, params.mHash, mHashName);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+    }
+  }
+
+  virtual nsresult BeforeCrypto() override {
+    nsresult rv;
+
+    // If we're doing a JWK import, import the key data
+    if (mDataIsJwk) {
+      if (!mJwk.mK.WasPassed()) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      // Import the key material
+      rv = mKeyData.FromJwkBase64(mJwk.mK.Value());
+      if (NS_FAILED(rv)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+    }
+    // Check that we have valid key data.
+    if (mKeyData.Length() == 0 &&
+        !mAlgName.EqualsLiteral(WEBCRYPTO_ALG_PBKDF2)) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    // Construct an appropriate KeyAlorithm,
+    // and verify that usages are appropriate
+    if (mKeyData.Length() > UINT32_MAX / 8) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+    uint32_t length = 8 * mKeyData.Length();  // bytes to bits
+    if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+        mAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+        mAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM) ||
+        mAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW)) {
+      if (mKey->HasUsageOtherThan(CryptoKey::ENCRYPT | CryptoKey::DECRYPT |
+                                  CryptoKey::WRAPKEY | CryptoKey::UNWRAPKEY)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW) &&
+          mKey->HasUsageOtherThan(CryptoKey::WRAPKEY | CryptoKey::UNWRAPKEY)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      if ((length != 128) && (length != 192) && (length != 256)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+      mKey->Algorithm().MakeAes(mAlgName, length);
+
+      if (mDataIsJwk && mJwk.mUse.WasPassed() &&
+          !mJwk.mUse.Value().EqualsLiteral(JWK_USE_ENC)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+    } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_HKDF) ||
+               mAlgName.EqualsLiteral(WEBCRYPTO_ALG_PBKDF2)) {
+      if (mKey->HasUsageOtherThan(CryptoKey::DERIVEKEY |
+                                  CryptoKey::DERIVEBITS)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+      mKey->Algorithm().MakeAes(mAlgName, length);
+
+      if (mDataIsJwk && mJwk.mUse.WasPassed()) {
+        // There is not a 'use' value consistent with PBKDF or HKDF
+        return NS_ERROR_DOM_DATA_ERR;
+      };
+    } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_HMAC)) {
+      if (mKey->HasUsageOtherThan(CryptoKey::SIGN | CryptoKey::VERIFY)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      mKey->Algorithm().MakeHmac(length, mHashName);
+
+      if (mKey->Algorithm().Mechanism() == UNKNOWN_CK_MECHANISM) {
+        return NS_ERROR_DOM_SYNTAX_ERR;
+      }
+
+      if (mDataIsJwk && mJwk.mUse.WasPassed() &&
+          !mJwk.mUse.Value().EqualsLiteral(JWK_USE_SIG)) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+    } else {
+      return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+    }
+
+    if (NS_FAILED(mKey->SetSymKey(mKeyData))) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    mKey->SetType(CryptoKey::SECRET);
+
+    if (mDataIsJwk && !JwkCompatible(mJwk, mKey)) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    mEarlyComplete = true;
+    return NS_OK;
+  }
+
+ private:
+  nsString mHashName;
+};
+
+class ImportRsaKeyTask : public ImportKeyTask {
+ public:
+  ImportRsaKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                   const nsAString& aFormat, const ObjectOrString& aAlgorithm,
+                   bool aExtractable, const Sequence<nsString>& aKeyUsages)
+      : mModulusLength(0) {
+    Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable, aKeyUsages);
+  }
+
+  ImportRsaKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                   const nsAString& aFormat, JS::Handle<JSObject*> aKeyData,
+                   const ObjectOrString& aAlgorithm, bool aExtractable,
+                   const Sequence<nsString>& aKeyUsages)
+      : mModulusLength(0) {
+    Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable, aKeyUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    SetKeyData(aCx, aKeyData);
+    NS_ENSURE_SUCCESS_VOID(mEarlyRv);
+    if (mDataIsJwk && !mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+  }
+
+  void Init(nsIGlobalObject* aGlobal, JSContext* aCx, const nsAString& aFormat,
+            const ObjectOrString& aAlgorithm, bool aExtractable,
+            const Sequence<nsString>& aKeyUsages) {
+    ImportKeyTask::Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable,
+                        aKeyUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    // If this is RSA with a hash, cache the hash name
+    if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+        mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP) ||
+        mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS)) {
+      RootedDictionary<RsaHashedImportParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+        return;
+      }
+
+      mEarlyRv = GetAlgorithmName(aCx, params.mHash, mHashName);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+        return;
+      }
+    }
+
+    // Check support for the algorithm and hash names
+    CK_MECHANISM_TYPE mech1 = MapAlgorithmNameToMechanism(mAlgName);
+    CK_MECHANISM_TYPE mech2 = MapAlgorithmNameToMechanism(mHashName);
+    if ((mech1 == UNKNOWN_CK_MECHANISM) || (mech2 == UNKNOWN_CK_MECHANISM)) {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+  }
+
+ private:
+  nsString mHashName;
+  uint32_t mModulusLength;
+  CryptoBuffer mPublicExponent;
+
+  virtual nsresult DoCrypto() override {
+    // Import the key data itself
+    UniqueSECKEYPublicKey pubKey;
+    UniqueSECKEYPrivateKey privKey;
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI) ||
+        (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK) &&
+         !mJwk.mD.WasPassed())) {
+      // Public key import
+      if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI)) {
+        pubKey = CryptoKey::PublicKeyFromSpki(mKeyData);
+      } else {
+        pubKey = CryptoKey::PublicKeyFromJwk(mJwk);
+      }
+
+      if (!pubKey) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      if (NS_FAILED(mKey->SetPublicKey(pubKey.get()))) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      mKey->SetType(CryptoKey::PUBLIC);
+    } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8) ||
+               (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK) &&
+                mJwk.mD.WasPassed())) {
+      // Private key import
+      if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8)) {
+        privKey = CryptoKey::PrivateKeyFromPkcs8(mKeyData);
+      } else {
+        privKey = CryptoKey::PrivateKeyFromJwk(mJwk);
+      }
+
+      if (!privKey) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      if (NS_FAILED(mKey->SetPrivateKey(privKey.get()))) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      mKey->SetType(CryptoKey::PRIVATE);
+      pubKey = UniqueSECKEYPublicKey(SECKEY_ConvertToPublicKey(privKey.get()));
+      if (!pubKey) {
+        return NS_ERROR_DOM_UNKNOWN_ERR;
+      }
+    } else {
+      // Invalid key format
+      return NS_ERROR_DOM_SYNTAX_ERR;
+    }
+
+    if (pubKey->keyType != rsaKey) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+    // Extract relevant information from the public key
+    mModulusLength = 8 * pubKey->u.rsa.modulus.len;
+    if (!mPublicExponent.Assign(&pubKey->u.rsa.publicExponent)) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    return NS_OK;
+  }
+
+  virtual nsresult AfterCrypto() override {
+    // Check permissions for the requested operation
+    if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP)) {
+      if ((mKey->GetKeyType() == CryptoKey::PUBLIC &&
+           mKey->HasUsageOtherThan(CryptoKey::ENCRYPT | CryptoKey::WRAPKEY)) ||
+          (mKey->GetKeyType() == CryptoKey::PRIVATE &&
+           mKey->HasUsageOtherThan(CryptoKey::DECRYPT |
+                                   CryptoKey::UNWRAPKEY))) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+    } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+               mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS)) {
+      if ((mKey->GetKeyType() == CryptoKey::PUBLIC &&
+           mKey->HasUsageOtherThan(CryptoKey::VERIFY)) ||
+          (mKey->GetKeyType() == CryptoKey::PRIVATE &&
+           mKey->HasUsageOtherThan(CryptoKey::SIGN))) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+    }
+
+    // Set an appropriate KeyAlgorithm
+    if (!mKey->Algorithm().MakeRsa(mAlgName, mModulusLength, mPublicExponent,
+                                   mHashName)) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    if (mDataIsJwk && !JwkCompatible(mJwk, mKey)) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    return NS_OK;
+  }
+};
+
+class ImportEcKeyTask : public ImportKeyTask {
+ public:
+  ImportEcKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                  const nsAString& aFormat, const ObjectOrString& aAlgorithm,
+                  bool aExtractable, const Sequence<nsString>& aKeyUsages) {
+    Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable, aKeyUsages);
+  }
+
+  ImportEcKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                  const nsAString& aFormat, JS::Handle<JSObject*> aKeyData,
+                  const ObjectOrString& aAlgorithm, bool aExtractable,
+                  const Sequence<nsString>& aKeyUsages) {
+    Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable, aKeyUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    SetKeyData(aCx, aKeyData);
+    NS_ENSURE_SUCCESS_VOID(mEarlyRv);
+  }
+
+  void Init(nsIGlobalObject* aGlobal, JSContext* aCx, const nsAString& aFormat,
+            const ObjectOrString& aAlgorithm, bool aExtractable,
+            const Sequence<nsString>& aKeyUsages) {
+    ImportKeyTask::Init(aGlobal, aCx, aFormat, aAlgorithm, aExtractable,
+                        aKeyUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW)) {
+      RootedDictionary<EcKeyImportParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv) || !params.mNamedCurve.WasPassed()) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      if (!NormalizeToken(params.mNamedCurve.Value(), mNamedCurve)) {
+        mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        return;
+      }
+    }
+  }
+
+ private:
+  nsString mNamedCurve;
+
+  virtual nsresult DoCrypto() override {
+    // Import the key data itself
+    UniqueSECKEYPublicKey pubKey;
+    UniqueSECKEYPrivateKey privKey;
+
+    if ((mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK) &&
+         mJwk.mD.WasPassed()) ||
+        mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8)) {
+      // Private key import
+      if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+        privKey = CryptoKey::PrivateKeyFromJwk(mJwk);
+        if (!privKey) {
+          return NS_ERROR_DOM_DATA_ERR;
+        }
+      } else {
+        privKey = CryptoKey::PrivateKeyFromPkcs8(mKeyData);
+        if (!privKey) {
+          return NS_ERROR_DOM_DATA_ERR;
+        }
+
+        ScopedAutoSECItem ecParams;
+        if (PK11_ReadRawAttribute(PK11_TypePrivKey, privKey.get(),
+                                  CKA_EC_PARAMS, &ecParams) != SECSuccess) {
+          return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        }
+        // Construct the OID tag.
+        SECItem oid = {siBuffer, nullptr, 0};
+        oid.len = ecParams.data[1];
+        oid.data = ecParams.data + 2;
+        // Find a matching and supported named curve.
+        if (!MapOIDTagToNamedCurve(SECOID_FindOIDTag(&oid), mNamedCurve)) {
+          return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        }
+      }
+
+      if (NS_FAILED(mKey->SetPrivateKey(privKey.get()))) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      mKey->SetType(CryptoKey::PRIVATE);
+    } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW) ||
+               mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI) ||
+               (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK) &&
+                !mJwk.mD.WasPassed())) {
+      // Public key import
+      if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW)) {
+        pubKey = CryptoKey::PublicECKeyFromRaw(mKeyData, mNamedCurve);
+      } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI)) {
+        pubKey = CryptoKey::PublicKeyFromSpki(mKeyData);
+      } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+        pubKey = CryptoKey::PublicKeyFromJwk(mJwk);
+      } else {
+        MOZ_ASSERT(false);
+      }
+
+      if (!pubKey) {
+        return NS_ERROR_DOM_DATA_ERR;
+      }
+
+      if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI)) {
+        if (pubKey->keyType != ecKey) {
+          return NS_ERROR_DOM_DATA_ERR;
+        }
+        if (!CheckEncodedECParameters(&pubKey->u.ec.DEREncodedParams)) {
+          return NS_ERROR_DOM_OPERATION_ERR;
+        }
+
+        // Construct the OID tag.
+        SECItem oid = {siBuffer, nullptr, 0};
+        oid.len = pubKey->u.ec.DEREncodedParams.data[1];
+        oid.data = pubKey->u.ec.DEREncodedParams.data + 2;
+
+        // Find a matching and supported named curve.
+        if (!MapOIDTagToNamedCurve(SECOID_FindOIDTag(&oid), mNamedCurve)) {
+          return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        }
+      }
+
+      if (NS_FAILED(mKey->SetPublicKey(pubKey.get()))) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      mKey->SetType(CryptoKey::PUBLIC);
+    } else {
+      return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+    }
+
+    // Extract 'crv' parameter from JWKs.
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      if (!NormalizeToken(mJwk.mCrv.Value(), mNamedCurve)) {
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      }
+    }
+    return NS_OK;
+  }
+
+  virtual nsresult AfterCrypto() override {
+    uint32_t privateAllowedUsages = 0, publicAllowedUsages = 0;
+    if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDH)) {
+      privateAllowedUsages = CryptoKey::DERIVEBITS | CryptoKey::DERIVEKEY;
+      publicAllowedUsages = CryptoKey::DERIVEBITS | CryptoKey::DERIVEKEY;
+    } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+      privateAllowedUsages = CryptoKey::SIGN;
+      publicAllowedUsages = CryptoKey::VERIFY;
+    }
+
+    // Check permissions for the requested operation
+    if ((mKey->GetKeyType() == CryptoKey::PRIVATE &&
+         mKey->HasUsageOtherThan(privateAllowedUsages)) ||
+        (mKey->GetKeyType() == CryptoKey::PUBLIC &&
+         mKey->HasUsageOtherThan(publicAllowedUsages))) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    mKey->Algorithm().MakeEc(mAlgName, mNamedCurve);
+
+    if (mDataIsJwk && !JwkCompatible(mJwk, mKey)) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    return NS_OK;
+  }
+};
+
+class ExportKeyTask : public WebCryptoTask {
+ public:
+  ExportKeyTask(const nsAString& aFormat, CryptoKey& aKey)
+      : mFormat(aFormat),
+        mPrivateKey(aKey.GetPrivateKey()),
+        mPublicKey(aKey.GetPublicKey()),
+        mKeyType(aKey.GetKeyType()),
+        mExtractable(aKey.Extractable()),
+        mAlg(aKey.Algorithm().JwkAlg()) {
+    aKey.GetUsages(mKeyUsages);
+
+    if (!mSymKey.Assign(aKey.GetSymKey())) {
+      mEarlyRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+  }
+
+ protected:
+  nsString mFormat;
+  CryptoBuffer mSymKey;
+  UniqueSECKEYPrivateKey mPrivateKey;
+  UniqueSECKEYPublicKey mPublicKey;
+  CryptoKey::KeyType mKeyType;
+  bool mExtractable;
+  nsString mAlg;
+  nsTArray<nsString> mKeyUsages;
+  CryptoBuffer mResult;
+  JsonWebKey mJwk;
+
+ private:
+  virtual nsresult DoCrypto() override {
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW)) {
+      if (mPublicKey && mPublicKey->keyType == dhKey) {
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      }
+
+      if (mPublicKey && mPublicKey->keyType == ecKey) {
+        nsresult rv = CryptoKey::PublicECKeyToRaw(mPublicKey.get(), mResult);
+        if (NS_FAILED(rv)) {
+          return NS_ERROR_DOM_OPERATION_ERR;
+        }
+        return NS_OK;
+      }
+
+      if (!mResult.Assign(mSymKey)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+      if (mResult.Length() == 0) {
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      }
+
+      return NS_OK;
+    } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8)) {
+      if (!mPrivateKey) {
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      }
+
+      switch (mPrivateKey->keyType) {
+        case rsaKey:
+        case ecKey: {
+          nsresult rv =
+              CryptoKey::PrivateKeyToPkcs8(mPrivateKey.get(), mResult);
+          if (NS_FAILED(rv)) {
+            return NS_ERROR_DOM_OPERATION_ERR;
+          }
+          return NS_OK;
+        }
+        default:
+          return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      }
+    } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI)) {
+      if (!mPublicKey) {
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      }
+
+      return CryptoKey::PublicKeyToSpki(mPublicKey.get(), mResult);
+    } else if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      if (mKeyType == CryptoKey::SECRET) {
+        nsString k;
+        nsresult rv = mSymKey.ToJwkBase64(k);
+        if (NS_FAILED(rv)) {
+          return NS_ERROR_DOM_OPERATION_ERR;
+        }
+        mJwk.mK.Construct(k);
+        mJwk.mKty = NS_LITERAL_STRING_FROM_CSTRING(JWK_TYPE_SYMMETRIC);
+      } else if (mKeyType == CryptoKey::PUBLIC) {
+        if (!mPublicKey) {
+          return NS_ERROR_DOM_UNKNOWN_ERR;
+        }
+
+        nsresult rv = CryptoKey::PublicKeyToJwk(mPublicKey.get(), mJwk);
+        if (NS_FAILED(rv)) {
+          return NS_ERROR_DOM_OPERATION_ERR;
+        }
+      } else if (mKeyType == CryptoKey::PRIVATE) {
+        if (!mPrivateKey) {
+          return NS_ERROR_DOM_UNKNOWN_ERR;
+        }
+
+        nsresult rv = CryptoKey::PrivateKeyToJwk(mPrivateKey.get(), mJwk);
+        if (NS_FAILED(rv)) {
+          return NS_ERROR_DOM_OPERATION_ERR;
+        }
+      }
+
+      if (!mAlg.IsEmpty()) {
+        mJwk.mAlg.Construct(mAlg);
+      }
+
+      mJwk.mExt.Construct(mExtractable);
+
+      mJwk.mKey_ops.Construct();
+      if (!mJwk.mKey_ops.Value().AppendElements(mKeyUsages, fallible)) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+
+      return NS_OK;
+    }
+
+    return NS_ERROR_DOM_SYNTAX_ERR;
+  }
+
+  // Returns mResult as an ArrayBufferView or JWK, as appropriate
+  virtual void Resolve() override {
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      mResultPromise->MaybeResolve(mJwk);
+      return;
+    }
+
+    TypedArrayCreator<ArrayBuffer> ret(mResult);
+    mResultPromise->MaybeResolve(ret);
+  }
+};
+
+class GenerateSymmetricKeyTask : public WebCryptoTask {
+ public:
+  GenerateSymmetricKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                           const ObjectOrString& aAlgorithm, bool aExtractable,
+                           const Sequence<nsString>& aKeyUsages) {
+    // Create an empty key and set easy attributes
+    mKey = new CryptoKey(aGlobal);
+    mKey->SetExtractable(aExtractable);
+    mKey->SetType(CryptoKey::SECRET);
+
+    // Extract algorithm name
+    nsString algName;
+    mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, algName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    // Construct an appropriate KeyAlorithm
+    if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+        algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+        algName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM) ||
+        algName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW)) {
+      mEarlyRv = GetKeyLengthForAlgorithm(aCx, aAlgorithm, mLength);
+      if (NS_FAILED(mEarlyRv)) {
+        return;
+      }
+      mKey->Algorithm().MakeAes(algName, mLength);
+
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_HMAC)) {
+      RootedDictionary<HmacKeyGenParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv)) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      nsString hashName;
+      mEarlyRv = GetAlgorithmName(aCx, params.mHash, hashName);
+      if (NS_FAILED(mEarlyRv)) {
+        return;
+      }
+
+      if (params.mLength.WasPassed()) {
+        mLength = params.mLength.Value();
+      } else {
+        mLength = MapHashAlgorithmNameToBlockSize(hashName);
+      }
+
+      if (mLength == 0) {
+        mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+        return;
+      }
+
+      mKey->Algorithm().MakeHmac(mLength, hashName);
+    } else {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+
+    // Add key usages
+    mKey->ClearUsages();
+    for (uint32_t i = 0; i < aKeyUsages.Length(); ++i) {
+      mEarlyRv = mKey->AddAllowedUsageIntersecting(aKeyUsages[i], algName);
+      if (NS_FAILED(mEarlyRv)) {
+        return;
+      }
+    }
+    if (!mKey->HasAnyUsage()) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    mLength = mLength >> 3;  // bits to bytes
+    mMechanism = mKey->Algorithm().Mechanism();
+    // SetSymKey done in Resolve, after we've done the keygen
+  }
+
+ private:
+  RefPtr<CryptoKey> mKey;
+  size_t mLength;
+  CK_MECHANISM_TYPE mMechanism;
+  CryptoBuffer mKeyData;
+
+  virtual nsresult DoCrypto() override {
+    UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+    MOZ_ASSERT(slot.get());
+
+    UniquePK11SymKey symKey(
+        PK11_KeyGen(slot.get(), mMechanism, nullptr, mLength, nullptr));
+    if (!symKey) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    nsresult rv = MapSECStatus(PK11_ExtractKeyValue(symKey.get()));
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    // This doesn't leak, because the SECItem* returned by PK11_GetKeyData
+    // just refers to a buffer managed by symKey.  The assignment copies the
+    // data, so mKeyData manages one copy, while symKey manages another.
+    ATTEMPT_BUFFER_ASSIGN(mKeyData, PK11_GetKeyData(symKey.get()));
+    return NS_OK;
+  }
+
+  virtual void Resolve() override {
+    if (NS_SUCCEEDED(mKey->SetSymKey(mKeyData))) {
+      mResultPromise->MaybeResolve(mKey);
+    } else {
+      mResultPromise->MaybeReject(NS_ERROR_DOM_OPERATION_ERR);
+    }
+  }
+
+  virtual void Cleanup() override { mKey = nullptr; }
+};
+
+GenerateAsymmetricKeyTask::GenerateAsymmetricKeyTask(
+    nsIGlobalObject* aGlobal, JSContext* aCx, const ObjectOrString& aAlgorithm,
+    bool aExtractable, const Sequence<nsString>& aKeyUsages)
+    : mKeyPair(new CryptoKeyPair()),
+      mMechanism(CKM_INVALID_MECHANISM),
+      mRsaParams(),
+      mDhParams() {
+  mArena = UniquePLArenaPool(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
+  if (!mArena) {
+    mEarlyRv = NS_ERROR_DOM_UNKNOWN_ERR;
+    return;
+  }
+
+  // Create an empty key pair and set easy attributes
+  mKeyPair->mPrivateKey = new CryptoKey(aGlobal);
+  mKeyPair->mPublicKey = new CryptoKey(aGlobal);
+
+  // Extract algorithm name
+  mEarlyRv = GetAlgorithmName(aCx, aAlgorithm, mAlgName);
+  if (NS_FAILED(mEarlyRv)) {
+    return;
+  }
+
+  // Construct an appropriate KeyAlorithm
+  uint32_t privateAllowedUsages = 0, publicAllowedUsages = 0;
+  if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+      mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP) ||
+      mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS)) {
+    RootedDictionary<RsaHashedKeyGenParams> params(aCx);
+    mEarlyRv = Coerce(aCx, params, aAlgorithm);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    // Pull relevant info
+    uint32_t modulusLength = params.mModulusLength;
+    CryptoBuffer publicExponent;
+    ATTEMPT_BUFFER_INIT(publicExponent, params.mPublicExponent);
+    nsString hashName;
+    mEarlyRv = GetAlgorithmName(aCx, params.mHash, hashName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    // Create algorithm
+    if (!mKeyPair->mPublicKey->Algorithm().MakeRsa(mAlgName, modulusLength,
+                                                   publicExponent, hashName)) {
+      mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      return;
+    }
+    if (!mKeyPair->mPrivateKey->Algorithm().MakeRsa(mAlgName, modulusLength,
+                                                    publicExponent, hashName)) {
+      mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      return;
+    }
+    mMechanism = CKM_RSA_PKCS_KEY_PAIR_GEN;
+
+    // Set up params struct
+    mRsaParams.keySizeInBits = modulusLength;
+    bool converted = publicExponent.GetBigIntValue(mRsaParams.pe);
+    if (!converted) {
+      mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+      return;
+    }
+  } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDH) ||
+             mAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+    RootedDictionary<EcKeyGenParams> params(aCx);
+    mEarlyRv = Coerce(aCx, params, aAlgorithm);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    if (!NormalizeToken(params.mNamedCurve, mNamedCurve)) {
+      mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      return;
+    }
+
+    // Create algorithm.
+    mKeyPair->mPublicKey->Algorithm().MakeEc(mAlgName, mNamedCurve);
+    mKeyPair->mPrivateKey->Algorithm().MakeEc(mAlgName, mNamedCurve);
+    mMechanism = CKM_EC_KEY_PAIR_GEN;
+  } else {
+    mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+    return;
+  }
+
+  // Set key usages.
+  if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+      mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS) ||
+      mAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+    privateAllowedUsages = CryptoKey::SIGN;
+    publicAllowedUsages = CryptoKey::VERIFY;
+  } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP)) {
+    privateAllowedUsages = CryptoKey::DECRYPT | CryptoKey::UNWRAPKEY;
+    publicAllowedUsages = CryptoKey::ENCRYPT | CryptoKey::WRAPKEY;
+  } else if (mAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDH)) {
+    privateAllowedUsages = CryptoKey::DERIVEKEY | CryptoKey::DERIVEBITS;
+    publicAllowedUsages = 0;
+  } else {
+    MOZ_ASSERT(false);  // This shouldn't happen.
+  }
+
+  mKeyPair->mPrivateKey->SetExtractable(aExtractable);
+  mKeyPair->mPrivateKey->SetType(CryptoKey::PRIVATE);
+
+  mKeyPair->mPublicKey->SetExtractable(true);
+  mKeyPair->mPublicKey->SetType(CryptoKey::PUBLIC);
+
+  mKeyPair->mPrivateKey->ClearUsages();
+  mKeyPair->mPublicKey->ClearUsages();
+  for (uint32_t i = 0; i < aKeyUsages.Length(); ++i) {
+    mEarlyRv = mKeyPair->mPrivateKey->AddAllowedUsageIntersecting(
+        aKeyUsages[i], mAlgName, privateAllowedUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    mEarlyRv = mKeyPair->mPublicKey->AddAllowedUsageIntersecting(
+        aKeyUsages[i], mAlgName, publicAllowedUsages);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+  }
+}
+
+nsresult GenerateAsymmetricKeyTask::DoCrypto() {
+  MOZ_ASSERT(mKeyPair);
+
+  UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+  MOZ_ASSERT(slot.get());
+
+  void* param;
+  switch (mMechanism) {
+    case CKM_RSA_PKCS_KEY_PAIR_GEN:
+      param = &mRsaParams;
+      break;
+    case CKM_DH_PKCS_KEY_PAIR_GEN:
+      param = &mDhParams;
+      break;
+    case CKM_EC_KEY_PAIR_GEN: {
+      param = CreateECParamsForCurve(mNamedCurve, mArena.get());
+      if (!param) {
+        return NS_ERROR_DOM_UNKNOWN_ERR;
+      }
+      break;
+    }
+    default:
+      return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+  }
+
+  SECKEYPublicKey* pubKey = nullptr;
+  mPrivateKey = UniqueSECKEYPrivateKey(PK11_GenerateKeyPair(
+      slot.get(), mMechanism, param, &pubKey, PR_FALSE, PR_FALSE, nullptr));
+  mPublicKey = UniqueSECKEYPublicKey(pubKey);
+  pubKey = nullptr;
+  if (!mPrivateKey.get() || !mPublicKey.get()) {
+    return NS_ERROR_DOM_OPERATION_ERR;
+  }
+
+  // If no usages ended up being allowed, SyntaxError
+  if (!mKeyPair->mPrivateKey->HasAnyUsage()) {
+    return NS_ERROR_DOM_SYNTAX_ERR;
+  }
+
+  nsresult rv = mKeyPair->mPrivateKey->SetPrivateKey(mPrivateKey.get());
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+  rv = mKeyPair->mPublicKey->SetPublicKey(mPublicKey.get());
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+
+  // PK11_GenerateKeyPair() does not set a CKA_EC_POINT attribute on the
+  // private key, we need this later when exporting to PKCS8 and JWK though.
+  if (mMechanism == CKM_EC_KEY_PAIR_GEN) {
+    rv = mKeyPair->mPrivateKey->AddPublicKeyData(mPublicKey.get());
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_OPERATION_ERR);
+  }
+
+  return NS_OK;
+}
+
+void GenerateAsymmetricKeyTask::Resolve() {
+  mResultPromise->MaybeResolve(*mKeyPair);
+}
+
+void GenerateAsymmetricKeyTask::Cleanup() { mKeyPair = nullptr; }
+
+class DeriveHkdfBitsTask : public ReturnArrayBufferViewTask {
+ public:
+  DeriveHkdfBitsTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                     CryptoKey& aKey, uint32_t aLength)
+      : mMechanism(CKM_INVALID_MECHANISM) {
+    Init(aCx, aAlgorithm, aKey, aLength);
+  }
+
+  DeriveHkdfBitsTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                     CryptoKey& aKey, const ObjectOrString& aTargetAlgorithm)
+      : mLengthInBits(0), mLengthInBytes(0), mMechanism(CKM_INVALID_MECHANISM) {
+    size_t length;
+    mEarlyRv = GetKeyLengthForAlgorithm(aCx, aTargetAlgorithm, length);
+
+    if (NS_SUCCEEDED(mEarlyRv)) {
+      Init(aCx, aAlgorithm, aKey, length);
+    }
+  }
+
+  void Init(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            uint32_t aLength) {
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_HKDF);
+    CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_HKDF);
+
+    if (!mSymKey.Assign(aKey.GetSymKey())) {
+      mEarlyRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+
+    // Check that we have a key.
+    if (mSymKey.Length() == 0) {
+      mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+      return;
+    }
+
+    RootedDictionary<HkdfParams> params(aCx);
+    mEarlyRv = Coerce(aCx, params, aAlgorithm);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    // length must be greater than zero.
+    if (aLength == 0) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+
+    // Extract the hash algorithm.
+    nsString hashName;
+    mEarlyRv = GetAlgorithmName(aCx, params.mHash, hashName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    // Check the given hash algorithm.
+    switch (MapAlgorithmNameToMechanism(hashName)) {
+      case CKM_SHA_1:
+        mMechanism = CKM_NSS_HKDF_SHA1;
+        break;
+      case CKM_SHA256:
+        mMechanism = CKM_NSS_HKDF_SHA256;
+        break;
+      case CKM_SHA384:
+        mMechanism = CKM_NSS_HKDF_SHA384;
+        break;
+      case CKM_SHA512:
+        mMechanism = CKM_NSS_HKDF_SHA512;
+        break;
+      default:
+        mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        return;
+    }
+
+    ATTEMPT_BUFFER_INIT(mSalt, params.mSalt)
+    ATTEMPT_BUFFER_INIT(mInfo, params.mInfo)
+    mLengthInBytes = ceil((double)aLength / 8);
+    mLengthInBits = aLength;
+  }
+
+ private:
+  size_t mLengthInBits;
+  size_t mLengthInBytes;
+  CryptoBuffer mSalt;
+  CryptoBuffer mInfo;
+  CryptoBuffer mSymKey;
+  CK_MECHANISM_TYPE mMechanism;
+
+  virtual nsresult DoCrypto() override {
+    UniquePLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
+    if (!arena) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // Import the key
+    SECItem keyItem = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &keyItem, mSymKey);
+
+    UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+    if (!slot.get()) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    UniquePK11SymKey baseKey(PK11_ImportSymKey(slot.get(), mMechanism,
+                                               PK11_OriginUnwrap, CKA_WRAP,
+                                               &keyItem, nullptr));
+    if (!baseKey) {
+      return NS_ERROR_DOM_INVALID_ACCESS_ERR;
+    }
+
+    SECItem salt = {siBuffer, nullptr, 0};
+    SECItem info = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &salt, mSalt);
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &info, mInfo);
+
+    CK_NSS_HKDFParams hkdfParams = {true, salt.data, salt.len,
+                                    true, info.data, info.len};
+    SECItem params = {siBuffer, (unsigned char*)&hkdfParams,
+                      sizeof(hkdfParams)};
+
+    // CKM_SHA512_HMAC and CKA_SIGN are key type and usage attributes of the
+    // derived symmetric key and don't matter because we ignore them anyway.
+    UniquePK11SymKey symKey(PK11_Derive(baseKey.get(), mMechanism, &params,
+                                        CKM_SHA512_HMAC, CKA_SIGN,
+                                        mLengthInBytes));
+
+    if (!symKey.get()) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    nsresult rv = MapSECStatus(PK11_ExtractKeyValue(symKey.get()));
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // This doesn't leak, because the SECItem* returned by PK11_GetKeyData
+    // just refers to a buffer managed by symKey. The assignment copies the
+    // data, so mResult manages one copy, while symKey manages another.
+    ATTEMPT_BUFFER_ASSIGN(mResult, PK11_GetKeyData(symKey.get()));
+
+    if (mLengthInBytes > mResult.Length()) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    if (!mResult.SetLength(mLengthInBytes, fallible)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    // If the number of bits to derive is not a multiple of 8 we need to
+    // zero out the remaining bits that were derived but not requested.
+    if (mLengthInBits % 8) {
+      mResult[mResult.Length() - 1] &= 0xff << (mLengthInBits % 8);
+    }
+
+    return NS_OK;
+  }
+};
+
+class DerivePbkdfBitsTask : public ReturnArrayBufferViewTask {
+ public:
+  DerivePbkdfBitsTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                      CryptoKey& aKey, uint32_t aLength)
+      : mHashOidTag(SEC_OID_UNKNOWN) {
+    Init(aCx, aAlgorithm, aKey, aLength);
+  }
+
+  DerivePbkdfBitsTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                      CryptoKey& aKey, const ObjectOrString& aTargetAlgorithm)
+      : mLength(0), mIterations(0), mHashOidTag(SEC_OID_UNKNOWN) {
+    size_t length;
+    mEarlyRv = GetKeyLengthForAlgorithm(aCx, aTargetAlgorithm, length);
+
+    if (NS_SUCCEEDED(mEarlyRv)) {
+      Init(aCx, aAlgorithm, aKey, length);
+    }
+  }
+
+  void Init(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+            uint32_t aLength) {
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_PBKDF2);
+    CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_PBKDF2);
+
+    if (!mSymKey.Assign(aKey.GetSymKey())) {
+      mEarlyRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+
+    RootedDictionary<Pbkdf2Params> params(aCx);
+    mEarlyRv = Coerce(aCx, params, aAlgorithm);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    // length must be a multiple of 8 bigger than zero.
+    if (aLength == 0 || aLength % 8) {
+      mEarlyRv = NS_ERROR_DOM_OPERATION_ERR;
+      return;
+    }
+
+    // Extract the hash algorithm.
+    nsString hashName;
+    mEarlyRv = GetAlgorithmName(aCx, params.mHash, hashName);
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    // Check the given hash algorithm.
+    switch (MapAlgorithmNameToMechanism(hashName)) {
+      case CKM_SHA_1:
+        mHashOidTag = SEC_OID_HMAC_SHA1;
+        break;
+      case CKM_SHA256:
+        mHashOidTag = SEC_OID_HMAC_SHA256;
+        break;
+      case CKM_SHA384:
+        mHashOidTag = SEC_OID_HMAC_SHA384;
+        break;
+      case CKM_SHA512:
+        mHashOidTag = SEC_OID_HMAC_SHA512;
+        break;
+      default:
+        mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        return;
+    }
+
+    ATTEMPT_BUFFER_INIT(mSalt, params.mSalt)
+    mLength = aLength >> 3;  // bits to bytes
+    mIterations = params.mIterations;
+  }
+
+ private:
+  size_t mLength;
+  size_t mIterations;
+  CryptoBuffer mSalt;
+  CryptoBuffer mSymKey;
+  SECOidTag mHashOidTag;
+
+  virtual nsresult DoCrypto() override {
+    UniquePLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
+    if (!arena) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    SECItem salt = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &salt, mSalt);
+    // PK11_CreatePBEV2AlgorithmID will "helpfully" create PBKDF2 parameters
+    // with a random salt if given a SECItem* that is either null or has a null
+    // data pointer. This obviously isn't what we want, so we have to fake it
+    // out by passing in a SECItem* with a non-null data pointer but with zero
+    // length.
+    if (!salt.data) {
+      MOZ_ASSERT(salt.len == 0);
+      salt.data =
+          reinterpret_cast<unsigned char*>(PORT_ArenaAlloc(arena.get(), 1));
+      if (!salt.data) {
+        return NS_ERROR_DOM_UNKNOWN_ERR;
+      }
+    }
+
+    // Always pass in cipherAlg=SEC_OID_HMAC_SHA1 (i.e. PBMAC1) as this
+    // parameter is unused for key generation. It is currently only used
+    // for PBKDF2 authentication or key (un)wrapping when specifying an
+    // encryption algorithm (PBES2).
+    UniqueSECAlgorithmID algID(
+        PK11_CreatePBEV2AlgorithmID(SEC_OID_PKCS5_PBKDF2, SEC_OID_HMAC_SHA1,
+                                    mHashOidTag, mLength, mIterations, &salt));
+
+    if (!algID) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    UniquePK11SlotInfo slot(PK11_GetInternalSlot());
+    if (!slot.get()) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    SECItem keyItem = {siBuffer, nullptr, 0};
+    ATTEMPT_BUFFER_TO_SECITEM(arena.get(), &keyItem, mSymKey);
+
+    UniquePK11SymKey symKey(
+        PK11_PBEKeyGen(slot.get(), algID.get(), &keyItem, false, nullptr));
+    if (!symKey.get()) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    nsresult rv = MapSECStatus(PK11_ExtractKeyValue(symKey.get()));
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // This doesn't leak, because the SECItem* returned by PK11_GetKeyData
+    // just refers to a buffer managed by symKey. The assignment copies the
+    // data, so mResult manages one copy, while symKey manages another.
+    ATTEMPT_BUFFER_ASSIGN(mResult, PK11_GetKeyData(symKey.get()));
+    return NS_OK;
+  }
+};
+
+template <class DeriveBitsTask>
+class DeriveKeyTask : public DeriveBitsTask {
+ public:
+  DeriveKeyTask(nsIGlobalObject* aGlobal, JSContext* aCx,
+                const ObjectOrString& aAlgorithm, CryptoKey& aBaseKey,
+                const ObjectOrString& aDerivedKeyType, bool aExtractable,
+                const Sequence<nsString>& aKeyUsages)
+      : DeriveBitsTask(aCx, aAlgorithm, aBaseKey, aDerivedKeyType) {
+    if (NS_FAILED(this->mEarlyRv)) {
+      return;
+    }
+
+    constexpr auto format =
+        NS_LITERAL_STRING_FROM_CSTRING(WEBCRYPTO_KEY_FORMAT_RAW);
+    mTask = new ImportSymmetricKeyTask(aGlobal, aCx, format, aDerivedKeyType,
+                                       aExtractable, aKeyUsages);
+  }
+
+ protected:
+  RefPtr<ImportSymmetricKeyTask> mTask;
+
+ private:
+  virtual void Resolve() override {
+    mTask->SetRawKeyData(this->mResult);
+    mTask->DispatchWithPromise(this->mResultPromise);
+  }
+
+  virtual void Cleanup() override { mTask = nullptr; }
+};
+class DeriveEcdhBitsTask : public ReturnArrayBufferViewTask {
+ public:
+  DeriveEcdhBitsTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                     CryptoKey& aKey, uint32_t aLength)
+      : mLength(aLength), mPrivKey(aKey.GetPrivateKey()) {
+    Init(aCx, aAlgorithm, aKey);
+  }
+
+  DeriveEcdhBitsTask(JSContext* aCx, const ObjectOrString& aAlgorithm,
+                     CryptoKey& aKey, const ObjectOrString& aTargetAlgorithm)
+      : mPrivKey(aKey.GetPrivateKey()) {
+    mEarlyRv = GetKeyLengthForAlgorithm(aCx, aTargetAlgorithm, mLength);
+    if (NS_SUCCEEDED(mEarlyRv)) {
+      Init(aCx, aAlgorithm, aKey);
+    }
+  }
+
+  void Init(JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey) {
+    Telemetry::Accumulate(Telemetry::WEBCRYPTO_ALG, TA_ECDH);
+    CHECK_KEY_ALGORITHM(aKey.Algorithm(), WEBCRYPTO_ALG_ECDH);
+
+    // Check that we have a private key.
+    if (!mPrivKey) {
+      mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+      return;
+    }
+
+    // Length must be a multiple of 8 bigger than zero.
+    if (mLength == 0 || mLength % 8) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+
+    mLength = mLength >> 3;  // bits to bytes
+
+    // Retrieve the peer's public key.
+    RootedDictionary<EcdhKeyDeriveParams> params(aCx);
+    mEarlyRv = Coerce(aCx, params, aAlgorithm);
+    if (NS_FAILED(mEarlyRv)) {
+      mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+      return;
+    }
+
+    CryptoKey* publicKey = params.mPublic;
+    mPubKey = publicKey->GetPublicKey();
+    if (!mPubKey) {
+      mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
+      return;
+    }
+
+    CHECK_KEY_ALGORITHM(publicKey->Algorithm(), WEBCRYPTO_ALG_ECDH);
+
+    // Both keys must use the same named curve.
+    nsString curve1 = aKey.Algorithm().mEc.mNamedCurve;
+    nsString curve2 = publicKey->Algorithm().mEc.mNamedCurve;
+
+    if (!curve1.Equals(curve2)) {
+      mEarlyRv = NS_ERROR_DOM_DATA_ERR;
+      return;
+    }
+  }
+
+ private:
+  size_t mLength;
+  UniqueSECKEYPrivateKey mPrivKey;
+  UniqueSECKEYPublicKey mPubKey;
+
+  virtual nsresult DoCrypto() override {
+    // CKM_SHA512_HMAC and CKA_SIGN are key type and usage attributes of the
+    // derived symmetric key and don't matter because we ignore them anyway.
+    UniquePK11SymKey symKey(
+        PK11_PubDeriveWithKDF(mPrivKey.get(), mPubKey.get(), PR_FALSE, nullptr,
+                              nullptr, CKM_ECDH1_DERIVE, CKM_SHA512_HMAC,
+                              CKA_SIGN, 0, CKD_NULL, nullptr, nullptr));
+
+    if (!symKey.get()) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    nsresult rv = MapSECStatus(PK11_ExtractKeyValue(symKey.get()));
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_DOM_OPERATION_ERR;
+    }
+
+    // This doesn't leak, because the SECItem* returned by PK11_GetKeyData
+    // just refers to a buffer managed by symKey. The assignment copies the
+    // data, so mResult manages one copy, while symKey manages another.
+    ATTEMPT_BUFFER_ASSIGN(mResult, PK11_GetKeyData(symKey.get()));
+
+    if (mLength > mResult.Length()) {
+      return NS_ERROR_DOM_DATA_ERR;
+    }
+
+    if (!mResult.SetLength(mLength, fallible)) {
+      return NS_ERROR_DOM_UNKNOWN_ERR;
+    }
+
+    return NS_OK;
+  }
+};
+
+template <class KeyEncryptTask>
+class WrapKeyTask : public ExportKeyTask {
+ public:
+  WrapKeyTask(JSContext* aCx, const nsAString& aFormat, CryptoKey& aKey,
+              CryptoKey& aWrappingKey, const ObjectOrString& aWrapAlgorithm)
+      : ExportKeyTask(aFormat, aKey) {
+    if (NS_FAILED(mEarlyRv)) {
+      return;
+    }
+
+    mTask = new KeyEncryptTask(aCx, aWrapAlgorithm, aWrappingKey, true);
+  }
+
+ private:
+  RefPtr<KeyEncryptTask> mTask;
+
+  virtual nsresult AfterCrypto() override {
+    // If wrapping JWK, stringify the JSON
+    if (mFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+      nsAutoString json;
+      if (!mJwk.ToJSON(json)) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+
+      NS_ConvertUTF16toUTF8 utf8(json);
+      if (!mResult.Assign((const uint8_t*)utf8.BeginReading(), utf8.Length())) {
+        return NS_ERROR_DOM_OPERATION_ERR;
+      }
+    }
+
+    return NS_OK;
+  }
+
+  virtual void Resolve() override {
+    mTask->SetData(mResult);
+    mTask->DispatchWithPromise(mResultPromise);
+  }
+
+  virtual void Cleanup() override { mTask = nullptr; }
+};
+
+template <class KeyEncryptTask>
+class UnwrapKeyTask : public KeyEncryptTask {
+ public:
+  UnwrapKeyTask(JSContext* aCx, const ArrayBufferViewOrArrayBuffer& aWrappedKey,
+                CryptoKey& aUnwrappingKey,
+                const ObjectOrString& aUnwrapAlgorithm, ImportKeyTask* aTask)
+      : KeyEncryptTask(aCx, aUnwrapAlgorithm, aUnwrappingKey, aWrappedKey,
+                       false),
+        mTask(aTask) {}
+
+ private:
+  RefPtr<ImportKeyTask> mTask;
+
+  virtual void Resolve() override {
+    mTask->SetKeyDataMaybeParseJWK(KeyEncryptTask::mResult);
+    mTask->DispatchWithPromise(KeyEncryptTask::mResultPromise);
+  }
+
+  virtual void Cleanup() override { mTask = nullptr; }
+};
+
+// Task creation methods for WebCryptoTask
+
+// Note: We do not perform algorithm normalization as a monolithic process,
+// as described in the spec.  Instead:
+// * Each method handles its slice of the supportedAlgorithms structure
+// * Task constructors take care of:
+//    * Coercing the algorithm to the proper concrete type
+//    * Cloning subordinate data items
+//    * Cloning input data as needed
+//
+// Thus, support for different algorithms is determined by the if-statements
+// below, rather than a data structure.
+//
+// This results in algorithm normalization coming after some other checks,
+// and thus slightly more steps being done synchronously than the spec calls
+// for.  But none of these steps is especially time-consuming.
+
+WebCryptoTask* WebCryptoTask::CreateEncryptDecryptTask(
+    JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+    const CryptoOperationData& aData, bool aEncrypt) {
+  TelemetryMethod method = (aEncrypt) ? TM_ENCRYPT : TM_DECRYPT;
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, method);
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_EXTRACTABLE_ENC,
+                        aKey.Extractable());
+
+  // Ensure key is usable for this operation
+  if ((aEncrypt && !aKey.HasUsage(CryptoKey::ENCRYPT)) ||
+      (!aEncrypt && !aKey.HasUsage(CryptoKey::DECRYPT))) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM)) {
+    return new AesTask(aCx, aAlgorithm, aKey, aData, aEncrypt);
+  } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP)) {
+    return new RsaOaepTask(aCx, aAlgorithm, aKey, aData, aEncrypt);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateSignVerifyTask(
+    JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+    const CryptoOperationData& aSignature, const CryptoOperationData& aData,
+    bool aSign) {
+  TelemetryMethod method = (aSign) ? TM_SIGN : TM_VERIFY;
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, method);
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_EXTRACTABLE_SIG,
+                        aKey.Extractable());
+
+  // Ensure key is usable for this operation
+  if ((aSign && !aKey.HasUsage(CryptoKey::SIGN)) ||
+      (!aSign && !aKey.HasUsage(CryptoKey::VERIFY))) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_HMAC)) {
+    return new HmacTask(aCx, aAlgorithm, aKey, aSignature, aData, aSign);
+  } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+             algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS) ||
+             algName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+    return new AsymmetricSignVerifyTask(aCx, aAlgorithm, aKey, aSignature,
+                                        aData, aSign);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateDigestTask(
+    JSContext* aCx, const ObjectOrString& aAlgorithm,
+    const CryptoOperationData& aData) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_DIGEST);
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_SHA1) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_SHA256) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_SHA384) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_SHA512)) {
+    return new DigestTask(aCx, aAlgorithm, aData);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateImportKeyTask(
+    nsIGlobalObject* aGlobal, JSContext* aCx, const nsAString& aFormat,
+    JS::Handle<JSObject*> aKeyData, const ObjectOrString& aAlgorithm,
+    bool aExtractable, const Sequence<nsString>& aKeyUsages) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_IMPORTKEY);
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_EXTRACTABLE_IMPORT, aExtractable);
+
+  // Verify that the format is recognized
+  if (!aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  // Verify that aKeyUsages does not contain an unrecognized value
+  if (!CryptoKey::AllUsagesRecognized(aKeyUsages)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  // SPEC-BUG: PBKDF2 is not supposed to be supported for this operation.
+  // However, the spec should be updated to allow it.
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_PBKDF2) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_HKDF) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_HMAC)) {
+    return new ImportSymmetricKeyTask(aGlobal, aCx, aFormat, aKeyData,
+                                      aAlgorithm, aExtractable, aKeyUsages);
+  } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+             algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP) ||
+             algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS)) {
+    return new ImportRsaKeyTask(aGlobal, aCx, aFormat, aKeyData, aAlgorithm,
+                                aExtractable, aKeyUsages);
+  } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_ECDH) ||
+             algName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+    return new ImportEcKeyTask(aGlobal, aCx, aFormat, aKeyData, aAlgorithm,
+                               aExtractable, aKeyUsages);
+  } else {
+    return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+  }
+}
+
+WebCryptoTask* WebCryptoTask::CreateExportKeyTask(const nsAString& aFormat,
+                                                  CryptoKey& aKey) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_EXPORTKEY);
+
+  // Verify that the format is recognized
+  if (!aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  // Verify that the key is extractable
+  if (!aKey.Extractable()) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  // Verify that the algorithm supports export
+  // SPEC-BUG: PBKDF2 is not supposed to be supported for this operation.
+  // However, the spec should be updated to allow it.
+  nsString algName = aKey.Algorithm().mName;
+  if (algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_PBKDF2) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_HMAC) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_PSS) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA) ||
+      algName.EqualsLiteral(WEBCRYPTO_ALG_ECDH)) {
+    return new ExportKeyTask(aFormat, aKey);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateGenerateKeyTask(
+    nsIGlobalObject* aGlobal, JSContext* aCx, const ObjectOrString& aAlgorithm,
+    bool aExtractable, const Sequence<nsString>& aKeyUsages) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_GENERATEKEY);
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_EXTRACTABLE_GENERATE,
+                        aExtractable);
+
+  if (!CryptoKey::AllUsagesRecognized(aKeyUsages)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_AES_CBC) ||
+      algName.EqualsASCII(WEBCRYPTO_ALG_AES_CTR) ||
+      algName.EqualsASCII(WEBCRYPTO_ALG_AES_GCM) ||
+      algName.EqualsASCII(WEBCRYPTO_ALG_AES_KW) ||
+      algName.EqualsASCII(WEBCRYPTO_ALG_HMAC)) {
+    return new GenerateSymmetricKeyTask(aGlobal, aCx, aAlgorithm, aExtractable,
+                                        aKeyUsages);
+  } else if (algName.EqualsASCII(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+             algName.EqualsASCII(WEBCRYPTO_ALG_RSA_OAEP) ||
+             algName.EqualsASCII(WEBCRYPTO_ALG_RSA_PSS) ||
+             algName.EqualsASCII(WEBCRYPTO_ALG_ECDH) ||
+             algName.EqualsASCII(WEBCRYPTO_ALG_ECDSA)) {
+    return new GenerateAsymmetricKeyTask(aGlobal, aCx, aAlgorithm, aExtractable,
+                                         aKeyUsages);
+  } else {
+    return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+  }
+}
+
+WebCryptoTask* WebCryptoTask::CreateDeriveKeyTask(
+    nsIGlobalObject* aGlobal, JSContext* aCx, const ObjectOrString& aAlgorithm,
+    CryptoKey& aBaseKey, const ObjectOrString& aDerivedKeyType,
+    bool aExtractable, const Sequence<nsString>& aKeyUsages) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_DERIVEKEY);
+
+  // Ensure baseKey is usable for this operation
+  if (!aBaseKey.HasUsage(CryptoKey::DERIVEKEY)) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  // Verify that aKeyUsages does not contain an unrecognized value
+  if (!CryptoKey::AllUsagesRecognized(aKeyUsages)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_HKDF)) {
+    return new DeriveKeyTask<DeriveHkdfBitsTask>(aGlobal, aCx, aAlgorithm,
+                                                 aBaseKey, aDerivedKeyType,
+                                                 aExtractable, aKeyUsages);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_PBKDF2)) {
+    return new DeriveKeyTask<DerivePbkdfBitsTask>(aGlobal, aCx, aAlgorithm,
+                                                  aBaseKey, aDerivedKeyType,
+                                                  aExtractable, aKeyUsages);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_ECDH)) {
+    return new DeriveKeyTask<DeriveEcdhBitsTask>(aGlobal, aCx, aAlgorithm,
+                                                 aBaseKey, aDerivedKeyType,
+                                                 aExtractable, aKeyUsages);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateDeriveBitsTask(
+    JSContext* aCx, const ObjectOrString& aAlgorithm, CryptoKey& aKey,
+    uint32_t aLength) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_DERIVEBITS);
+
+  // Ensure baseKey is usable for this operation
+  if (!aKey.HasUsage(CryptoKey::DERIVEBITS)) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  nsString algName;
+  nsresult rv = GetAlgorithmName(aCx, aAlgorithm, algName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_PBKDF2)) {
+    return new DerivePbkdfBitsTask(aCx, aAlgorithm, aKey, aLength);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_ECDH)) {
+    return new DeriveEcdhBitsTask(aCx, aAlgorithm, aKey, aLength);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_HKDF)) {
+    return new DeriveHkdfBitsTask(aCx, aAlgorithm, aKey, aLength);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateWrapKeyTask(
+    JSContext* aCx, const nsAString& aFormat, CryptoKey& aKey,
+    CryptoKey& aWrappingKey, const ObjectOrString& aWrapAlgorithm) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_WRAPKEY);
+
+  // Verify that the format is recognized
+  if (!aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_RAW) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_SPKI) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_PKCS8) &&
+      !aFormat.EqualsLiteral(WEBCRYPTO_KEY_FORMAT_JWK)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  // Ensure wrappingKey is usable for this operation
+  if (!aWrappingKey.HasUsage(CryptoKey::WRAPKEY)) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  // Ensure key is extractable
+  if (!aKey.Extractable()) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  nsString wrapAlgName;
+  nsresult rv = GetAlgorithmName(aCx, aWrapAlgorithm, wrapAlgName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  if (wrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+      wrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+      wrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM)) {
+    return new WrapKeyTask<AesTask>(aCx, aFormat, aKey, aWrappingKey,
+                                    aWrapAlgorithm);
+  } else if (wrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW)) {
+    return new WrapKeyTask<AesKwTask>(aCx, aFormat, aKey, aWrappingKey,
+                                      aWrapAlgorithm);
+  } else if (wrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP)) {
+    return new WrapKeyTask<RsaOaepTask>(aCx, aFormat, aKey, aWrappingKey,
+                                        aWrapAlgorithm);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask* WebCryptoTask::CreateUnwrapKeyTask(
+    nsIGlobalObject* aGlobal, JSContext* aCx, const nsAString& aFormat,
+    const ArrayBufferViewOrArrayBuffer& aWrappedKey, CryptoKey& aUnwrappingKey,
+    const ObjectOrString& aUnwrapAlgorithm,
+    const ObjectOrString& aUnwrappedKeyAlgorithm, bool aExtractable,
+    const Sequence<nsString>& aKeyUsages) {
+  Telemetry::Accumulate(Telemetry::WEBCRYPTO_METHOD, TM_UNWRAPKEY);
+
+  // Ensure key is usable for this operation
+  if (!aUnwrappingKey.HasUsage(CryptoKey::UNWRAPKEY)) {
+    return new FailureTask(NS_ERROR_DOM_INVALID_ACCESS_ERR);
+  }
+
+  // Verify that aKeyUsages does not contain an unrecognized value
+  if (!CryptoKey::AllUsagesRecognized(aKeyUsages)) {
+    return new FailureTask(NS_ERROR_DOM_SYNTAX_ERR);
+  }
+
+  nsString keyAlgName;
+  nsresult rv = GetAlgorithmName(aCx, aUnwrappedKeyAlgorithm, keyAlgName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+
+  CryptoOperationData dummy;
+  RefPtr<ImportKeyTask> importTask;
+  if (keyAlgName.EqualsASCII(WEBCRYPTO_ALG_AES_CBC) ||
+      keyAlgName.EqualsASCII(WEBCRYPTO_ALG_AES_CTR) ||
+      keyAlgName.EqualsASCII(WEBCRYPTO_ALG_AES_GCM) ||
+      keyAlgName.EqualsASCII(WEBCRYPTO_ALG_AES_KW) ||
+      keyAlgName.EqualsASCII(WEBCRYPTO_ALG_HKDF) ||
+      keyAlgName.EqualsASCII(WEBCRYPTO_ALG_HMAC)) {
+    importTask = new ImportSymmetricKeyTask(aGlobal, aCx, aFormat,
+                                            aUnwrappedKeyAlgorithm,
+                                            aExtractable, aKeyUsages);
+  } else if (keyAlgName.EqualsASCII(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
+             keyAlgName.EqualsASCII(WEBCRYPTO_ALG_RSA_OAEP) ||
+             keyAlgName.EqualsASCII(WEBCRYPTO_ALG_RSA_PSS)) {
+    importTask =
+        new ImportRsaKeyTask(aGlobal, aCx, aFormat, aUnwrappedKeyAlgorithm,
+                             aExtractable, aKeyUsages);
+  } else if (keyAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDH) ||
+             keyAlgName.EqualsLiteral(WEBCRYPTO_ALG_ECDSA)) {
+    importTask =
+        new ImportEcKeyTask(aGlobal, aCx, aFormat, aUnwrappedKeyAlgorithm,
+                            aExtractable, aKeyUsages);
+  } else {
+    return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+  }
+
+  nsString unwrapAlgName;
+  rv = GetAlgorithmName(aCx, aUnwrapAlgorithm, unwrapAlgName);
+  if (NS_FAILED(rv)) {
+    return new FailureTask(rv);
+  }
+  if (unwrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_CBC) ||
+      unwrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_CTR) ||
+      unwrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_GCM)) {
+    return new UnwrapKeyTask<AesTask>(aCx, aWrappedKey, aUnwrappingKey,
+                                      aUnwrapAlgorithm, importTask);
+  } else if (unwrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_AES_KW)) {
+    return new UnwrapKeyTask<AesKwTask>(aCx, aWrappedKey, aUnwrappingKey,
+                                        aUnwrapAlgorithm, importTask);
+  } else if (unwrapAlgName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP)) {
+    return new UnwrapKeyTask<RsaOaepTask>(aCx, aWrappedKey, aUnwrappingKey,
+                                          aUnwrapAlgorithm, importTask);
+  }
+
+  return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+}
+
+WebCryptoTask::WebCryptoTask()
+    : CancelableRunnable("WebCryptoTask"),
+      mEarlyRv(NS_OK),
+      mEarlyComplete(false),
+      mOriginalEventTarget(nullptr),
+      mRv(NS_ERROR_NOT_INITIALIZED) {}
+
+WebCryptoTask::~WebCryptoTask() = default;
+
+}  // namespace mozilla::dom