fix stack overflow on recursive export trie #28
Conversation
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
When the export trie is malformed and is recursive, this Exported::parse() will stack overflow when trying to parse it. Detect this condition and return an error instead. This is implemented by remembering the list of parent nodes that we visited in the trie, and erroring if we ever try to visit the same node a second time. I initially tried to implement it by ensuring that the Cursor always makes forward progress when parsing the trie, but some valid binaries, e.g. /usr/bin/smbd layout their trie in a way that requires to sometime jump backwards to get the child nodes.
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Outdated suggestions cannot be applied.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.
Found this bug when fuzzing the crate
When the export trie is malformed and is recursive,
Exported::parse()will stack overflow when trying to parse it.Detect this condition and return an error instead. This is implemented by remembering the list of parent nodes that we visited in the trie, and erroring if we ever try to visit the same node a second time.
I initially tried to implement it by ensuring that the Cursor always makes forward progress when parsing the trie, but some valid binaries, e.g. /usr/bin/smbd layout their trie in a way that requires to sometime jump backwards to get the child nodes.