From d2f116c6bb99e4de7778f152a874e750e46a45a8 Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Wed, 7 Apr 2021 09:09:33 -0700
Subject: [PATCH] crypto: fixup randomFill size and offset handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/38138
Fixes: https://github.com/nodejs/node/issues/38137
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
---
 lib/internal/crypto/random.js       | 6 +++---
 test/parallel/test-crypto-random.js | 7 +++++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/internal/crypto/random.js b/lib/internal/crypto/random.js
index 88b535a357c4fa..e966074daa53c5 100644
--- a/lib/internal/crypto/random.js
+++ b/lib/internal/crypto/random.js
@@ -155,10 +155,11 @@ function randomFill(buf, offset, size, callback) {
   if (typeof offset === 'function') {
     callback = offset;
     offset = 0;
-    size = buf.bytesLength;
+    // Size is a length here, assertSize() call turns it into a number of bytes
+    size = buf.length;
   } else if (typeof size === 'function') {
     callback = size;
-    size = buf.byteLength - offset;
+    size = buf.length - offset;
   } else {
     validateCallback(callback);
   }
@@ -176,7 +177,6 @@ function randomFill(buf, offset, size, callback) {
     return;
   }
 
-  // TODO(@jasnell): This is not yet handling byte offsets right
   const job = new RandomBytesJob(
     kCryptoJobAsync,
     buf,
diff --git a/test/parallel/test-crypto-random.js b/test/parallel/test-crypto-random.js
index 4f0c7dbb43f634..752bb8779f313d 100644
--- a/test/parallel/test-crypto-random.js
+++ b/test/parallel/test-crypto-random.js
@@ -525,3 +525,10 @@ assert.throws(
     assert.throws(() => crypto.randomInt(0, 1, i), cbError);
   });
 }
+
+{
+  // Verify that it doesn't throw or abort
+  crypto.randomFill(new Uint16Array(10), 0, common.mustSucceed());
+  crypto.randomFill(new Uint32Array(10), 0, common.mustSucceed());
+  crypto.randomFill(new Uint32Array(10), 0, 1, common.mustSucceed());
+}