Add a signature validation budget during path construction#14960
Merged
Conversation
This extends our existing NC budget check to include a budget for signature validations. If a path construction exceeds the budget by performing more than the allowed number of signature validation steps, the entire construction fails. For now, our budget is 128 signature validations. This is consistent with (higher than) Go and rustls-webpki, which both set a limit of 100. Like Go, we attempt to make the "best" use of our signature budget by ordering by likelihood, using AKI/SKI match as the strongest signal of fitness.
This reverts commit bcdb680.
woodruffw
commented
Jun 7, 2026
Comment on lines
+627
to
+631
| #[test] | ||
| fn test_clone() { | ||
| assert_eq!(NullOps::clone_public_key(&()), ()); | ||
| assert_eq!(NullOps::clone_extra(&()), ()); | ||
| } |
Member
Author
There was a problem hiding this comment.
We need NullOps for the coverage below, which means we need to "test" the empty trait impl bodies we add.
(We already do this for another test-only impl, PulicKeyErrorOps.)
woodruffw
commented
Jun 7, 2026
| .ok() | ||
| .unwrap(); | ||
| let err = builder | ||
| .build_chain_inner(&working, u8::MAX, &ca_exts, name_chain, &mut budget) |
Member
Author
There was a problem hiding this comment.
This single line is the coverage-bearing one.
alex
approved these changes
Jun 7, 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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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 extends our existing NC budget check to include a budget for signature validations. If a path construction exceeds the budget by performing more than the allowed number of signature validation steps, the entire construction fails.
For now, our budget is 128 signature validations. This is consistent with (higher than) Go and rustls-webpki, which both set a limit of 100. Like Go, we attempt to make the "best" use of our signature budget by ordering by likelihood, using AKI/SKI match as the strongest signal of fitness.