Bug 1034855 - Implement generateKey() for ECDH r=rbarnes,keeler

dom/crypto/WebCryptoCommon.h

@@ -49,6 +49,11 @@
 #define WEBCRYPTO_KEY_USAGE_WRAPKEY     "wrapKey"
 #define WEBCRYPTO_KEY_USAGE_UNWRAPKEY   "unwrapKey"
 
+// WebCrypto named curves
+#define WEBCRYPTO_NAMED_CURVE_P256  "P-256"
+#define WEBCRYPTO_NAMED_CURVE_P384  "P-384"
+#define WEBCRYPTO_NAMED_CURVE_P521  "P-521"
+
 // JWK key types
 #define JWK_TYPE_SYMMETRIC          "oct"
 #define JWK_TYPE_RSA                "RSA"
@@ -184,6 +189,88 @@ MapAlgorithmNameToMechanism(const nsString& aName)
   return mechanism;
 }
 
+inline bool
+NormalizeNamedCurveValue(const nsString& aNamedCurve, nsString& aDest)
+{
+  if (aNamedCurve.EqualsIgnoreCase(WEBCRYPTO_NAMED_CURVE_P256)) {
+    aDest.AssignLiteral(WEBCRYPTO_NAMED_CURVE_P256);
+  } else if (aNamedCurve.EqualsIgnoreCase(WEBCRYPTO_NAMED_CURVE_P384)) {
+    aDest.AssignLiteral(WEBCRYPTO_NAMED_CURVE_P384);
+  } else if (aNamedCurve.EqualsIgnoreCase(WEBCRYPTO_NAMED_CURVE_P521)) {
+    aDest.AssignLiteral(WEBCRYPTO_NAMED_CURVE_P521);
+  } else {
+    return false;
+  }
+
+  return true;
+}
+
+inline bool
+CheckEncodedECParameters(const SECItem* aEcParams)
+{
+  // Need at least two bytes for a valid ASN.1 encoding.
+  if (aEcParams->len < 2) {
+    return false;
+  }
+
+  // Check the ASN.1 tag.
+  if (aEcParams->data[0] != SEC_ASN1_OBJECT_ID) {
+    return false;
+  }
+
+  // OID tags are short, we never need more than one length byte.
+  if (aEcParams->data[1] >= 128) {
+    return false;
+  }
+
+  // Check that the SECItem's length is correct.
+  if (aEcParams->len != (unsigned)aEcParams->data[1] + 2) {
+    return false;
+  }
+
+  return true;
+}
+
+inline SECItem*
+CreateECParamsForCurve(const nsString& aNamedCurve, PLArenaPool* aArena)
+{
+  SECOidTag curveOIDTag;
+
+  if (aNamedCurve.EqualsLiteral(WEBCRYPTO_NAMED_CURVE_P256)) {
+    curveOIDTag = SEC_OID_SECG_EC_SECP256R1;
+  } else if (aNamedCurve.EqualsLiteral(WEBCRYPTO_NAMED_CURVE_P384)) {
+    curveOIDTag = SEC_OID_SECG_EC_SECP384R1;
+  } else if (aNamedCurve.EqualsLiteral(WEBCRYPTO_NAMED_CURVE_P521)) {
+    curveOIDTag = SEC_OID_SECG_EC_SECP521R1;
+  } else {
+    return nullptr;
+  }
+
+  // Retrieve curve data by OID tag.
+  SECOidData* oidData = SECOID_FindOIDByTag(curveOIDTag);
+  if (!oidData) {
+    return nullptr;
+  }
+
+  // Create parameters.
+  SECItem* params = ::SECITEM_AllocItem(aArena, nullptr, 2 + oidData->oid.len);
+  if (!params) {
+    return nullptr;
+  }
+
+  // Set parameters.
+  params->data[0] = SEC_ASN1_OBJECT_ID;
+  params->data[1] = oidData->oid.len;
+  memcpy(params->data + 2, oidData->oid.data, oidData->oid.len);
+
+  // Sanity check the params we just created.
+  if (!CheckEncodedECParameters(params)) {
+    return nullptr;
+  }
+
+  return params;
+}
+
 } // namespace dom
 } // namespace mozilla
 

dom/crypto/WebCryptoTask.cpp

@@ -2000,6 +2000,24 @@ public:
         mEarlyRv = NS_ERROR_DOM_INVALID_ACCESS_ERR;
         return;
       }
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_ECDH)) {
+      RootedDictionary<EcKeyGenParams> params(aCx);
+      mEarlyRv = Coerce(aCx, params, aAlgorithm);
+      if (NS_FAILED(mEarlyRv) || !params.mNamedCurve.WasPassed()) {
+        mEarlyRv = NS_ERROR_DOM_SYNTAX_ERR;
+        return;
+      }
+
+      if (!NormalizeNamedCurveValue(params.mNamedCurve.Value(), mNamedCurve)) {
+        mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+        return;
+      }
+
+      // Create algorithm.
+      algorithm = new EcKeyAlgorithm(global, algName, mNamedCurve);
+      mKeyPair->PublicKey()->SetAlgorithm(algorithm);
+      mKeyPair->PrivateKey()->SetAlgorithm(algorithm);
+      mMechanism = CKM_EC_KEY_PAIR_GEN;
     } else {
       mEarlyRv = NS_ERROR_DOM_NOT_SUPPORTED_ERR;
       return;
@@ -2013,6 +2031,9 @@ public:
                algName.EqualsLiteral(WEBCRYPTO_ALG_RSA_OAEP)) {
       privateAllowedUsages = CryptoKey::DECRYPT | CryptoKey::UNWRAPKEY;
       publicAllowedUsages = CryptoKey::ENCRYPT | CryptoKey::WRAPKEY;
+    } else if (algName.EqualsLiteral(WEBCRYPTO_ALG_ECDH)) {
+      privateAllowedUsages = CryptoKey::DERIVEKEY | CryptoKey::DERIVEBITS;
+      publicAllowedUsages = 0;
     }
 
     mKeyPair->PrivateKey()->SetExtractable(aExtractable);
@@ -2044,6 +2065,7 @@ private:
   PK11RSAGenParams mRsaParams;
   ScopedSECKEYPublicKey mPublicKey;
   ScopedSECKEYPrivateKey mPrivateKey;
+  nsString mNamedCurve;
 
   virtual void ReleaseNSSResources() MOZ_OVERRIDE
   {
@@ -2057,9 +2079,26 @@ private:
     MOZ_ASSERT(slot.get());
 
     void* param;
+    ScopedPLArenaPool arena;
+
     switch (mMechanism) {
-      case CKM_RSA_PKCS_KEY_PAIR_GEN: param = &mRsaParams; break;
-      default: return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+      case CKM_RSA_PKCS_KEY_PAIR_GEN:
+        param = &mRsaParams;
+        break;
+      case CKM_EC_KEY_PAIR_GEN: {
+        arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
+        if (!arena) {
+          return NS_ERROR_DOM_UNKNOWN_ERR;
+        }
+
+        param = CreateECParamsForCurve(mNamedCurve, arena.get());
+        if (!param) {
+          return NS_ERROR_DOM_UNKNOWN_ERR;
+        }
+        break;
+      }
+      default:
+        return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
     }
 
     SECKEYPublicKey* pubKey = nullptr;
@@ -2477,7 +2516,8 @@ WebCryptoTask::CreateGenerateKeyTask(JSContext* aCx,
     return new GenerateSymmetricKeyTask(aCx, aAlgorithm, aExtractable, aKeyUsages);
   } else if (algName.EqualsASCII(WEBCRYPTO_ALG_RSAES_PKCS1) ||
              algName.EqualsASCII(WEBCRYPTO_ALG_RSASSA_PKCS1) ||
-             algName.EqualsASCII(WEBCRYPTO_ALG_RSA_OAEP)) {
+             algName.EqualsASCII(WEBCRYPTO_ALG_RSA_OAEP) ||
+             algName.EqualsASCII(WEBCRYPTO_ALG_ECDH)) {
     return new GenerateAsymmetricKeyTask(aCx, aAlgorithm, aExtractable, aKeyUsages);
   } else {
     return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);

dom/crypto/test/tests.js

@@ -1867,3 +1867,31 @@ TestArray.addTest(
       .then(complete(that), error(that));
   }
 );
+
+// -----------------------------------------------------------------------------
+TestArray.addTest(
+  "Generate an ECDH key for named curve P-256",
+  function() {
+    var that = this;
+    var alg = { name: "ECDH", namedCurve: "P-256" };
+    crypto.subtle.generateKey(alg, false, ["deriveKey", "deriveBits"]).then(
+      complete(that, function(x) {
+        return exists(x.publicKey) &&
+               (x.publicKey.algorithm.name == alg.name) &&
+               (x.publicKey.algorithm.namedCurve == alg.namedCurve) &&
+               (x.publicKey.type == "public") &&
+               x.publicKey.extractable &&
+               (x.publicKey.usages.length == 0) &&
+               exists(x.privateKey) &&
+               (x.privateKey.algorithm.name == alg.name) &&
+               (x.privateKey.algorithm.namedCurve == alg.namedCurve) &&
+               (x.privateKey.type == "private") &&
+               !x.privateKey.extractable &&
+               (x.privateKey.usages.length == 2) &&
+               (x.privateKey.usages[0] == "deriveKey") &&
+               (x.privateKey.usages[1] == "deriveBits");
+      }),
+      error(that)
+    );
+  }
+);