buffer: avoid 32-bit truncation in copy beyond 2 GiB#62942
Open
maruthang wants to merge 1 commit intonodejs:mainfrom
Open
buffer: avoid 32-bit truncation in copy beyond 2 GiB#62942maruthang wants to merge 1 commit intonodejs:mainfrom
maruthang wants to merge 1 commit intonodejs:mainfrom
Conversation
`Buffer.prototype.copy` and `copyArrayBuffer` use Uint32Value() to read offset and length arguments in C++. Values larger than 2**32 are silently truncated, so a 4 GiB+ copy quietly drops bytes. Switch to IntegerValue() and widen internal types to size_t so the slow path handles the full kMaxLength range. The fast path keeps its uint32_t signature; values beyond UINT32_MAX naturally fall through to the slow path. Add a regression test gated on NODE_TEST_LARGE_BUFFER (matches test-buffer-tostring-4gb.js gating) so default CI does not need to allocate >4 GiB. Fixes: nodejs#55422 Signed-off-by: Maruthan G <maruthang4@gmail.com>
nodejs-github-bot
added
buffer
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Buffer.prototype.copyandcopyArrayBufferuse Uint32Value() toread offset and length arguments in C++. Values larger than 2**32
are silently truncated, so a 4 GiB+ copy quietly drops bytes.
Switch to IntegerValue() and widen internal types to size_t so the
slow path handles the full kMaxLength range. The fast path keeps
its uint32_t signature; values beyond UINT32_MAX naturally fall
through to the slow path.
Add a regression test gated on NODE_TEST_LARGE_BUFFER (matches
test-buffer-tostring-4gb.js gating) so default CI does not need
to allocate >4 GiB.
Note: I was unable to run a full local build on Windows (vcbuild.bat fails due to missing NASM and inaccessible WindowsApps Python). The patch mirrors the diagnosis posted by the issue reporter.
cpplintis clean. Looking forward to CI verification.Fixes: #55422