Attach GitHub token only to configured GitHub hosts - #3056
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De-ASI-INTERFACE
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Aug 13, 2026
De-ASI-INTERFACE
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Aug 13, 2026
BearerAuthTransport re-adds the Authorization header on every hop, which defeats net/http's cross-host redirect stripping. Scope the credential to the configured hosts so a redirect off them travels without the token. An empty AllowedHosts preserves prior behavior; the three production construction sites populate it from the configured REST, upload, GraphQL and raw hosts.
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BearerAuthTransportsets theAuthorizationheader on every request it processes. Go'snet/httpstrips theAuthorizationheader when a redirect crosses to a different host, but that only covers headers set on the initial request. Because this transport re-adds the header on every hop, a redirect that leaves the configured GitHub hosts would carry the token to the redirect target.Today that is not reachable with an attacker-controlled destination, because GitHub's cross-host redirects (release assets, archives) resolve to GitHub-owned hosts such as
objects.githubusercontent.comandcodeload.github.com. This change stops the transport from relying on that invariant: it attaches the token only when the request host is one of the configured GitHub hosts (REST, GraphQL, upload, raw), so any redirect off them travels without the credential.A
CheckRedirectthat stripsAuthorizationdoes not work here, because the header is re-added by the transport on the next hop. The credential decision has to live in the transport, at the point where the header is set. An emptyAllowedHostspreserves the prior behavior, so this is backward compatible; the three production construction sites populate it from the configured hosts.Tests cover the token being sent to allowed hosts, withheld from a non-allowed redirect target and from arbitrary hosts, and the empty-
AllowedHostsdefault. This is a hardening change, not a response to a known exploit.