Mitigation for timing attack in PKCS1v15 padding validation#1335
Open
Coralesoft wants to merge 1 commit intoweidai11:masterfrom
Open
Mitigation for timing attack in PKCS1v15 padding validation#1335Coralesoft wants to merge 1 commit intoweidai11:masterfrom
Coralesoft wants to merge 1 commit intoweidai11:masterfrom
Conversation
Replaces variable-time separator search with constant-time implementation to mitigate Marvin Attack (CVE-2022-4304). Uses bitwise operations to avoid data-dependent timing leaks. Fixes three timing vulnerabilities: - Variable-time while loop - Early return on invalid padding - Variable-length memcpy operation Fixes weidai11#1247
Coralesoft
changed the title
axistore80-coder
approved these changes
Mar 29, 2026
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
This PR addresses the Marvin Attack timing vulnerability reported in #1247.
Replaces variable-time separator search with constant-time implementation to mitigate the Marvin Attack (CVE-2023-50979). Uses bitwise operations to avoid data-dependent timing leaks.
What's fixed:
Implementation:
Testing:
The fix maintains full backward compatibility with existing PKCS#1 v1.5 functionality.
I've tested that RSA encryption/decryption still works correctly while eliminating the timing side channels.
Let me know if you'd like me to make any changes or if you have questions. I can supply test harnesses if needed.
Thanks
Colin
Fixes #1247