Harden release source execution

tools/release/govoplan_release/git_state.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import json
+import os
 from pathlib import Path
 import re
 import subprocess
@@ -165,16 +166,50 @@ def git_success(path: Path, *args: str, timeout: int = 10) -> bool:
 def git(path: Path, *args: str, timeout: int = 10) -> subprocess.CompletedProcess[str]:
     try:
         return subprocess.run(
-            ["git", *args],
+            ["/usr/bin/git", "-c", "core.hooksPath=/dev/null", *args],
             cwd=path,
             check=False,
             text=True,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
             timeout=timeout,
+            env=sanitized_git_environment(),
         )
     except subprocess.TimeoutExpired as exc:
-        return subprocess.CompletedProcess(["git", *args], 124, exc.stdout or "", exc.stderr or "git command timed out")
+        return subprocess.CompletedProcess(["/usr/bin/git", *args], 124, exc.stdout or "", exc.stderr or "git command timed out")
+
+
+def sanitized_git_environment(
+    source: dict[str, str] | None = None,
+) -> dict[str, str]:
+    """Keep only deliberate process/auth inputs and neutralize Git redirection."""
+
+    environment = os.environ if source is None else source
+    result = {
+        key: environment[key]
+        for key in (
+            "HOME",
+            "LANG",
+            "LC_ALL",
+            "LC_CTYPE",
+            "SSH_AUTH_SOCK",
+        )
+        if environment.get(key)
+    }
+    result.update(
+        {
+            "GIT_CONFIG_GLOBAL": os.devnull,
+            "GIT_CONFIG_NOSYSTEM": "1",
+            "GIT_CONFIG_COUNT": "0",
+            "GIT_NO_REPLACE_OBJECTS": "1",
+            "GIT_OPTIONAL_LOCKS": "0",
+            "GIT_PAGER": "cat",
+            "GIT_SSH_COMMAND": "/usr/bin/ssh -o BatchMode=yes -o ConnectTimeout=8",
+            "GIT_TERMINAL_PROMPT": "0",
+            "PATH": "/usr/bin:/bin",
+        }
+    )
+    return result
 
 
 def git_error(result: subprocess.CompletedProcess[str]) -> str: