Open
Conversation
Currently it is allowed in chunk extensions, but not if there is no extension.
Old versions of Google Frontend, Akamai Global Host, and Apache Traffic Server (ATS) considered a bare '\n' to end the extension and forwarded it unchainged. If a server allows '\n' inside a chunk extension and is behind one of these, the combination is vulnerable to request smuggling. If a client allows '\n' inside a chunk extension and is in front of one of these, the combination is vulnerable to response splitting. Google Frontend and Akamai Global Host are cloud-only, but old ATS versions may still exist in the wild. Thanks to Ben Kallus for pointing out that old versions of ATS, Google Frontend, and Akamai Global Host had this bug.
Right now, a chunk size with no hex digits is considered equivalent to a chunk size with only zeros.
A chunk size must have at least one hex digit. If there are no hex digits at all, the chunk size is invalid.
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
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
RFC9112 does not allow them bare LF in chunk extensions, and an endpoint that allows bare LF in chunk extensions is necessary for certain vulnerabilities in other components to be exploitable. In particular, old versions of Apache Traffic Server may still exist in the wild.