crypto: key size must be int32 in DiffieHellman()

The JS code accepted any value where `typeof sizeOrKey === 'number'`
was true but the C++ code checked that `args[0]->IsInt32()` and
subsequently aborted.

Fixes: https://github.com/nodejs/node/issues/32738

PR-URL: https://github.com/nodejs/node/pull/32739
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/internal/crypto/diffiehellman.js b/lib/internal/crypto/diffiehellman.js
index ae6b68b73b..70e4100d50 100644
--- a/lib/internal/crypto/diffiehellman.js
+++ b/lib/internal/crypto/diffiehellman.js
@@ -14,7 +14,10 @@ const {
   ERR_INVALID_ARG_TYPE,
   ERR_INVALID_OPT_VALUE
 } = require('internal/errors').codes;
-const { validateString } = require('internal/validators');
+const {
+  validateString,
+  validateInt32,
+} = require('internal/validators');
 const { isArrayBufferView } = require('internal/util/types');
 const { KeyObject } = require('internal/crypto/keys');
 const {
@@ -51,6 +54,13 @@ function DiffieHellman(sizeOrKey, keyEncoding, generator, genEncoding) {
     );
   }
 
+  // Sizes < 0 don't make sense but they _are_ accepted (and subsequently
+  // rejected with ERR_OSSL_BN_BITS_TOO_SMALL) by OpenSSL. The glue code
+  // in node_crypto.cc accepts values that are IsInt32() for that reason
+  // and that's why we do that here too.
+  if (typeof sizeOrKey === 'number')
+    validateInt32(sizeOrKey, 'sizeOrKey');
+
   if (keyEncoding && !Buffer.isEncoding(keyEncoding) &&
       keyEncoding !== 'buffer') {
     genEncoding = generator;