fix(git-auth): refuse non-GitHub hosts in the App credential helper#114
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Port of the host-allowlist our upstream contribution ships (NousResearch/hermes-agent#69972, commit 99fe8c7): git invokes credential helpers for EVERY https remote, so a helper that ignores the request's host= field hands the installation token to any URL a repo, submodule, or redirect points at. The boot-written gitconfig already scopes the helper to https://github.com; this enforces the same boundary inside the helper itself. get-credential now parses git's stdin description block and answers only for github.com / gist.github.com over https — anything else emits nothing and exits 0 so git falls through to the next helper. An empty request (manual smoke test) still answers, so existing invocations are unaffected. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Closes the gap our own upstream audit found in our deployed helper (fleet lessons 2026-07-23, item 6):
hermes_cli/github_app_token.pyanswered every credential request without checking thehost=field, relying solely on the boot-written scoped gitconfig.What
Port of the host-allowlist shipped in our upstream contribution (NousResearch/hermes-agent#69972, commit 99fe8c7):
get-credentialnow parses git's stdin credential description blockgithub.com/gist.github.comoverhttpsWhy
git invokes credential helpers for EVERY https remote. A malicious submodule or redirect pointing at an attacker host would previously have been handed the org installation token if the helper were ever wired unscoped. Defense in depth: the scoped gitconfig remains, and the helper now enforces the same boundary itself.
Tests
tests/hermes_cli/test_github_app_token.py22/22 pass;test_git_credentials_boot.py+test_gh_token_inject.py41/41 pass; ruff clean🤖 Generated with Claude Code