Conversation
…mand Implement dynamic runtime template parsing and validation inside HttpCommand to protect Discovery REST clients from path traversal and parameter injection exploits. Specifically, this change: - Rejects query (?) and fragment (#) characters in path parameter values. - Rejects slashes (/) and dots (. or ..) in simple path variables (standard wildcards). - Validates path traversals in reserved path variables (+ or #, double wildcards) using a segment-boundary traversal validation algorithm. In addition to the validation logic, this commit includes: - Ruby style modernization: cleaned up and auto-corrected string quote style to favor single quotes where appropriate. - Formatted long stub requests to follow style guidelines. Note: If the canonical specification is updated to favor the simpler alternative, this implementation can be easily simplified to "Fail always if dots are found in a double-wildcard value" by replacing the segment-traversal logic with a simple check for any "." or ".." substring.
quartzmo
force-pushed
the
discovery-core-validation
branch
from
August 4, 2026 22:43
66dff5d to
c84404d
Compare
quartzmo
marked this pull request as ready for review
August 4, 2026 23:55
torreypayne
approved these changes
Aug 10, 2026
torreypayne
left a comment
torreypayne
left a comment
Member
There was a problem hiding this comment.
This looks awesome! The only thing I'm wondering is if there are any test cases we could extract from the original vulnerability ask to ensure we have coverage. Otherwise LGTM!
aandreassa
reviewed
Aug 19, 2026
efevans
reviewed
Aug 28, 2026
torreypayne
reviewed
Sep 28, 2026
…re-level encoding
torreypayne
approved these changes
Sep 28, 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
4 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.
Implement dynamic runtime template parsing and validation inside HttpCommand to protect Discovery REST clients from path traversal and parameter injection exploits.
Summary of Changes
?) and fragment (#) characters in all path parameter values./) and exact.or..values in simple path variables (standard wildcards{var}).//or trailing slashes) and any path segments that are exactly.or..in reserved path variables (double wildcards{+var}and{#var}).%2e%2eand..%2f..) are safely encoded to%252e%252eand..%252f..on the wire byAddressable::Template.gapic-commonand .NET client library formats.Addressable Expansion Behavior
In Ruby Discovery clients, URI template expansion is handled by
Addressable::Template. Because RFC 6570 does not include%in theRESERVEDset,Addressable::Template#expandencodes%to%25on the wire (e.g.%2e%2eexpands to%252e%252e).This ensures that percent-encoded characters remain literal string data when decoded by downstream HTTP servers and reverse proxies (GFE, Envoy, Rack), preventing obfuscated directory traversal attempts.