Reject API access from browsers - #3380
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Any request carrying an `Origin` header is now rejected with 403 before the inner route runs: browsers set it on every cross-site request and every non-GET/HEAD request, while `curl` and `eclair-cli` never do. Checking presence rather than value also covers `Origin: null` and DNS rebinding. This is a defence against browser CSRF, not an authentication mechanism — `Origin` is trivially omitted by a non-browser client, and the API should still never be exposed beyond loopback. Breaking change: the API can no longer be called from a web browser, even same-origin; anyone serving a web front-end against it now needs their own back-end in front. Fixes project-loupe/audit-eclair#223, and by construction any other CSRF report against an individual endpoint.
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Any request carrying an
Originheader is now rejected with 403 before the inner route runs: browsers set it on every cross-site request and every non-GET/HEAD request, whilecurlandeclair-clinever do. Checking presence rather than value also coversOrigin: nulland DNS rebinding.This is a defence against browser CSRF, not an authentication mechanism —
Originis trivially omitted by a non-browser client, and the API should still never be exposed beyond loopback.Breaking change: the API can no longer be called from a web browser, even same-origin; anyone serving a web front-end against it now needs their own back-end in front.
Fixes project-loupe/audit-eclair#223, and by construction any other CSRF report against an individual endpoint.