src,crypto: relax RSA/EC keygen arg checks

Loosens two `AdditionalConfig` precondition checks so the new Web Crypto
keygen jobs added earlier (RsaKeyPairGenJob, EcKeyPairGenJob) can reuse
the shared traits without threading unused encoding args through the job
constructor.

  - `RsaKeyGenTraits::AdditionalConfig` now CHECKs RSA key
     type-dependant argument count accounting for being able to skip
     unused parameters.
  - `EcKeyGenTraits::AdditionalConfig` now defaults `param_encoding` to
    `OPENSSL_EC_NAMED_CURVE`, this is not observable in existing
    crypto.generateKeyPair(Sync) as its dispatch already applies the
    same default. This is just so that a stray OPENSSL_EC_NAMED_CURVE
    isn't needed in ec.js

Pure precondition relaxation — no new code paths. Existing
`generateKeyPair` callers still pass the same args and hit the same
branches.

Signed-off-by: Filip Skokan <[email protected]>

Author: panva

src/crypto/crypto_ec.cc

@@ -436,7 +436,6 @@ Maybe<void> EcKeyGenTraits::AdditionalConfig(
     EcKeyPairGenConfig* params) {
   Environment* env = Environment::GetCurrent(args);
   CHECK(args[*offset]->IsString());  // curve name
-  CHECK(args[*offset + 1]->IsInt32());  // param encoding
 
   Utf8Value curve_name(env->isolate(), args[*offset]);
   params->params.curve_nid = Ec::GetCurveIdFromName(*curve_name);
@@ -445,11 +444,17 @@ Maybe<void> EcKeyGenTraits::AdditionalConfig(
     return Nothing<void>();
   }
 
-  params->params.param_encoding = args[*offset + 1].As<Int32>()->Value();
-  if (params->params.param_encoding != OPENSSL_EC_NAMED_CURVE &&
-      params->params.param_encoding != OPENSSL_EC_EXPLICIT_CURVE) {
-    THROW_ERR_OUT_OF_RANGE(env, "Invalid param_encoding specified");
-    return Nothing<void>();
+  // param encoding
+  if (args[*offset + 1]->IsNullOrUndefined()) {
+    params->params.param_encoding = OPENSSL_EC_NAMED_CURVE;
+  } else {
+    CHECK(args[*offset + 1]->IsInt32());
+    params->params.param_encoding = args[*offset + 1].As<Int32>()->Value();
+    if (params->params.param_encoding != OPENSSL_EC_NAMED_CURVE &&
+        params->params.param_encoding != OPENSSL_EC_EXPLICIT_CURVE) {
+      THROW_ERR_OUT_OF_RANGE(env, "Invalid param_encoding specified");
+      return Nothing<void>();
+    }
   }
 
   *offset += 2;

src/crypto/crypto_rsa.cc

@@ -128,9 +128,9 @@ Maybe<void> RsaKeyGenTraits::AdditionalConfig(
       static_cast<RSAKeyVariant>(args[*offset].As<Uint32>()->Value());
 
   CHECK_IMPLIES(params->params.variant != kKeyVariantRSA_PSS,
-                args.Length() == 10);
+                static_cast<unsigned int>(args.Length()) >= *offset + 3);
   CHECK_IMPLIES(params->params.variant == kKeyVariantRSA_PSS,
-                args.Length() == 13);
+                static_cast<unsigned int>(args.Length()) >= *offset + 6);
 
   params->params.modulus_bits = args[*offset + 1].As<Uint32>()->Value();
   params->params.exponent = args[*offset + 2].As<Uint32>()->Value();