acl: use hostspec parser to disallow suffix hostname matches - #628
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the documented intent is that a .foo.com hostspec matches foo.com and anything ending in .foo.com; the former was silently wrong.
the existing ad-hoc parsing in acl.c allowed an attacker to use e.g. an "untrusted.net" domain name to access a reachable tinyproxy instance if it had an allow list entry for "trusted.net". exploiting it would require that the attacker has prior knowledge of the instance's configuration or is damn good at guessing and well-budgeted to register lots of potentially matching domains. fix by re-using the existing hardened hostspec parser. closes tinyproxy#627
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🟡 Changes recommended
Update the public ACL documentation to explain exact and leading-dot subdomain matching.
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Pull request overview
Updates ACL hostname matching to use boundary-aware hostspec parsing, preventing suffix-collision matches.
Changes:
- Adds exact and label-boundary hostname matching.
- Reuses
hostspec_matchfor ACL reverse-DNS checks. - Clarifies the changed apex-versus-subdomain semantics in the review notes.
File summaries
| File | Summary |
|---|---|
src/hostspec.c |
Implements exact and label-boundary hostname matching. |
src/acl.c |
Applies shared matching to ACL hostname checks; documentation should explain the new semantics. |
Review details
- Files reviewed: 2/2 changed files
- Comments generated: 1
- Review effort level: Lite
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