Bug: `location` blocks match path segments anywhere in the URL, not just at the start

[zdila]

Bug: location blocks match path segments anywhere in the URL, not just at the start

Summary

A location "/foo" block incorrectly matches requests whose URL contains /foo as any path segment, not only requests whose path starts with /foo. For example, location "/branding" matches /user/account/branding.

Environment

• Ferron version: (checked against current develop-2.x branch source)
• Configuration format: KDL

Steps to reproduce

Given ferron.kdl:

example.com {
    location "/branding" {
        proxy "https://s3.amazonaws.com/example/branding/"
    }

    location "/" {
        proxy "http://localhost:8080/"
    }
}

Send a request to https://example.com/user/account/branding. It is proxied to S3 instead of localhost:8080.

Expected behavior

location "/branding" should only match requests whose path equals /branding or starts with /branding/ (i.e. standard prefix matching anchored to the beginning of the path).

Actual behavior

location "/branding" matches any request containing branding as a path segment regardless of position — e.g. /user/account/branding, /a/b/c/branding/d.

Root cause

In ferron/src/config/lookup/tree.rs, the get method walks the request path segment by segment through the config trie. When a segment has no matching child node and no predicate matches, the inner while loop falls through to its next iteration instead of stopping. This causes unmatched segments to be silently skipped, so the traversal can eventually land on a deeper node (e.g. branding) even when the intermediate segments (user, account) did not match the configured location path.

Relevant code (before fix):

if conditional_predicate_matched {
    break;
}

// If nothing happened, probably no matching fixed multi-key or predicate single key found...
// ← no break here; loop continues with next segment

Fix

Add a break when no fixed key and no predicate matched. A wildcard_matched flag is needed to distinguish this case from a successful wildcard hostname match (e.g. *.example.com), which also exits the predicate for loop without setting conditional_predicate_matched:

if conditional_predicate_matched {
    break;
}
if !wildcard_matched {
    // No match found for this segment — stop traversal to prevent matching location
    // segments that appear later in the path.
    break;
}

The wildcard_matched flag is set to true inside the HostDomainLevelWildcard branch (replacing the old unmarked break out of the predicate loop).

Additional bug (unrelated)

In ferron-common/src/util/match_location.rs, line 16 reads:

req_path_prepared = path_prepared.replace("//", "/");

It should be:

req_path_prepared = req_path_prepared.replace("//", "/");

Using path_prepared here replaces the request path with the (already-normalized) location path whenever the request URL contains //, causing incorrect matching for such URLs.

[cuchaz]

I'm also running into this problem, so have my signal boost.

[DorianNiemiecSVRJS]

I have just confirmed the bug in the latest development version of Ferron 2 with this configuration:

:8080 {
  location "/test" {
    status 403
  }
  location "/" {
    status 200
  }
}

When I got curl localhost:8080/a/b/c/test, I indeed got a 403 error instead of 200.

[DorianNiemiecSVRJS]

I just fixed the bug (per your suggestion), the next versions of Ferron 2 and Ferron 2 LTS will have the fixes.