Fix CVE-2019-11815: strict BPF register state propagation in verifier #113
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
meta-cla
bot
added
the
CLA Signed
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Outdated suggestions cannot be applied.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.
Background
The BPF verifier did not correctly propagate register state across certain helper calls, which could allow crafted BPF programs to reach unsound states and cause verifier mis-acceptance, potential kernel crash, or undefined behavior. This is tracked as CVE-2019-11815.
Changes
Strengthen the BPF verifier’s register state tracking logic so that helper calls’ effects on register state are correctly reflected; reject programs that could otherwise leave registers in invalid/unsound states.
Security Impact
Prevents crafted BPF programs from exploiting verifier state inconsistencies, addressing CVE-2019-11815.
References
Upstream commit: 9955ac47f4ba1c95ecb6092aeaefb40a22e99268; CVE: CVE-2019-11815