security: harden against SAST findings (criticals through mediums)
Critical:
- Validate baseURL/sourceURL/upstreamURL at config load time
(prevents XML injection, XSS, SSRF via config/env manipulation)
- Use xml.Escape for OpenSearch XML template interpolation
High:
- Add security headers middleware (CSP, X-Frame-Options, HSTS, etc.)
- Sanitize result URLs to reject javascript:/data: schemes
- Sanitize infobox img_src against dangerous URL schemes
- Default CORS to deny-all (was wildcard *)
Medium:
- Rate limiter: X-Forwarded-For only trusted from configured proxies
- Validate engine names against known registry allowlist
- Add 1024-char max query length
- Sanitize upstream error messages (strip raw response bodies)
- Upstream client validates URL scheme (http/https only)
Test updates:
- Update extractIP tests for new trusted proxy behavior
Franz Kafka
da367a1bfd