bug(network): L7 path canonicalization treats percent-encoded %3B as a path-parameter delimiter and silently truncates the forwarded path

[CloneOfAlex]

User Story

As an operator running agents behind an L7 rest endpoint,
I want request paths that contain an encoded semicolon (%3B) to reach the upstream unchanged,
so that the agent acts on the resource it named and not on a different one.

Problem Statement

With the default strip_path_parameters: true, canonicalize_request_target percent-decodes %3B into a literal ; before splitting and stripping ;params. An encoded semicolon, which is data under RFC 3986, is then treated as a path-parameter delimiter: it and everything after it in that segment are dropped. Because the request line is rewritten with the canonical path (rewritten == true), the truncated path is what goes on the wire.

Observed with the canonicalizer from main (0ea0d31) built standalone:

request-target	canonical path sent upstream
/a/%3Bx	/a/
/objects/backup%3Bold	/objects/backup
/a/..;/b	/b (intended: ..; traversal guard)

Relevant code:

• decode:

  OpenShell/crates/openshell-supervisor-network/src/l7/path.rs

  Line 272 in 0ea0d31

  out.push(decoded);

• strip after decode:

  OpenShell/crates/openshell-supervisor-network/src/l7/path.rs

  Line 187 in 0ea0d31

  segments.into_iter().map(strip_path_parameters).collect()

• strip_path_parameters:

  OpenShell/crates/openshell-supervisor-network/src/l7/path.rs

  Line 284 in 0ea0d31

  fn strip_path_parameters(seg: &[u8]) -> &[u8] {

The existing tests (/public/..%3B/secret → /secret) cover the dot-segment case only; there is no test asserting that %3B inside an ordinary segment survives.

Impact / Why This Matters

The agent's request is retargeted without any error or log entry:

• DELETE /v1/objects/backup%3Bold is forwarded as DELETE /v1/objects/backup, which deletes a different object.
• GET/PUT on resource names, S3-style keys, or IDs that contain ; read or overwrite the wrong resource.
• Nothing is surfaced to the agent or operator (no OCSF event, no 4xx), so the data loss is silent.

The only workaround today is setting strip_path_parameters: false on the endpoint, which also disables the intended ;jsessionid-class mitigation.

Acceptance Criteria

• A %3B inside a non-dot segment is preserved as %3B in both the policy input and the forwarded request line (e.g. /a/b%3Bc → /a/b%3Bc).
• ..%3B / %2e%2e%3B traversal is still resolved or rejected as today.
• Alternatively, the request is rejected with a clear 4xx + OCSF event instead of being silently rewritten.
• Unit tests cover %3B in ordinary segments, including the trailing-segment case.

Reproduction Steps

1. Create a sandbox with a protocol: rest endpoint for a test upstream (e.g. an HTTP echo server) and an allow rule for /** with method *.
2. From inside the sandbox: curl -X DELETE "http://<upstream>/objects/backup%3Bold"
3. Observe the upstream receives DELETE /objects/backup.

Environment

• OpenShell: main @ 0ea0d31 (code review; canonicalizer exercised standalone)
• Component: openshell-supervisor-network L7 REST relay, default CanonicalizeOptions
• Any driver (the behavior is in the supervisor proxy)

Logs