Files
kandev/apps/backend/internal/worktree
João Salavisa ac8401b709 fix: harden submodule init against malicious .gitmodules (#1802)
* fix: harden submodule init against malicious .gitmodules

initSubmodules ran a bare `git submodule update --init --recursive` in a
worktree whose HEAD is attacker-controlled during a fork-PR review task,
with no protocol restriction, no hooks disable, and no cmd.Env. Attacker
`.gitmodules` could pick a command-executing transport (`ext::sh -c`,
CVE-2018-17456), a local `file://` path, or a plain-http URL (cloud
metadata SSRF).

Harden the single sink so all call sites benefit:
- protocol.allow=never default-denies every transport; only https/ssh are
  re-enabled (blocks file://, git://, plain http:// SSRF).
- protocol.ext.allow=never hard-pins the RCE transport off; on the command
  line it outranks any ambient protocol.ext.allow=always.
- core.hooksPath=/dev/null neutralizes attacker-planted hooks.
- GIT_TERMINAL_PROMPT=0 stops attacker URLs from hanging on a prompt.

Residual: attacker-chosen https/ssh URLs are still fetched (transports real
submodules require); fully closing that needs gating submodule init off for
untrusted worktrees, tracked separately.

* fix: address submodule hardening review feedback

- Reuse newNonInteractiveGitCmd so submodule init inherits the full
  non-interactive env set (GIT_SSH_COMMAND=ssh -oBatchMode=yes, SSH/GCM
  askpass suppression, WaitDelay). Prevents an attacker ssh:// submodule
  URL from hanging the review runner on host-key/passphrase prompts until
  the context deadline (GIT_TERMINAL_PROMPT=0 alone only covers git's HTTP
  prompt, not SSH).
- Correct the file:// comment: command-line -c outranks repo/global git
  config, so ambient protocol.file.allow=always does NOT re-enable file
  submodules here. This is intentional for untrusted trees; a trusted
  opt-in must be an explicit per-repo -c, not implicit host config.
- Add a file:// URL variant to the transport-block test alongside the
  bare-path form (CVE-2022-39253 classification differs by git version).

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Co-authored-by: Kandev Agent <agent@kandev.dev>
2026-07-19 16:12:56 +01:00
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