From 23943c5aa14cb4d9848513d43932a20daefc0363 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sat, 27 Jun 2026 16:19:47 +0000
Subject: [PATCH] Fix Command Injection vulnerability via malicious Git
 configuration

Disable core.fsmonitor when invoking Git commands via subprocess
to prevent potential command injection via a malicious .git/config
file in an untrusted directory. Added to src/wardline/core/delta.py
and src/wardline/core/legis.py. Also updated unit tests to match.

Co-authored-by: tachyon-beep <544926+tachyon-beep@users.noreply.github.com>
---
 .jules/sentinel.md            |  4 ++++
 src/wardline/core/delta.py    | 10 ++++++----
 src/wardline/core/legis.py    |  7 +++++--
 tests/unit/core/test_delta.py | 20 ++++++++++++++++++--
 4 files changed, 33 insertions(+), 8 deletions(-)
 create mode 100644 .jules/sentinel.md

diff --git a/.jules/sentinel.md b/.jules/sentinel.md
new file mode 100644
index 00000000..91405db0
--- /dev/null
+++ b/.jules/sentinel.md
@@ -0,0 +1,4 @@
+## 2024-05-18 - Prevent Command Injection via Malicious Git Configuration
+**Vulnerability:** Subprocess calls to `git` without `core.fsmonitor=false` can execute arbitrary commands if a malicious `.git/config` is present in an untrusted directory.
+**Learning:** Tools that scan or process untrusted directories must protect themselves against malicious local configuration files that tools like `git` might automatically load and execute.
+**Prevention:** When invoking `git` via `subprocess` against potentially untrusted directories, always apply the configuration `("-c", "core.fsmonitor=false")` (defined as `_SAFE_GIT_CONFIG`) to prevent local code execution.
diff --git a/src/wardline/core/delta.py b/src/wardline/core/delta.py
index c4d63f0e..764c3c47 100644
--- a/src/wardline/core/delta.py
+++ b/src/wardline/core/delta.py
@@ -11,6 +11,8 @@
 if TYPE_CHECKING:
     from wardline.scanner.index import Entity
 
+_SAFE_GIT_CONFIG = ("-c", "core.fsmonitor=false")
+
 
 def get_changed_files_since(ref: str, root: Path) -> set[str]:
     """Get the set of file paths (repo-relative, POSIX-style matching Location.path)
@@ -22,7 +24,7 @@ def get_changed_files_since(ref: str, root: Path) -> set[str]:
     # 1. Get the git toplevel directory.
     try:
         res = subprocess.run(
-            ["git", "rev-parse", "--show-toplevel"],
+            ["git", *_SAFE_GIT_CONFIG, "rev-parse", "--show-toplevel"],
             cwd=root,
             capture_output=True,
             text=True,
@@ -38,7 +40,7 @@ def get_changed_files_since(ref: str, root: Path) -> set[str]:
     # 2. Resolve ref to a verified object id before passing it to git diff.
     try:
         res = subprocess.run(
-            ["git", "rev-parse", "--verify", "--end-of-options", ref],
+            ["git", *_SAFE_GIT_CONFIG, "rev-parse", "--verify", "--end-of-options", ref],
             cwd=git_toplevel,
             capture_output=True,
             text=True,
@@ -54,7 +56,7 @@ def get_changed_files_since(ref: str, root: Path) -> set[str]:
     # 3. Get changed files since ref (committed since ref, staged, unstaged).
     try:
         res = subprocess.run(
-            ["git", "diff", "--name-only", verified_ref, "--"],
+            ["git", *_SAFE_GIT_CONFIG, "diff", "--name-only", verified_ref, "--"],
             cwd=git_toplevel,
             capture_output=True,
             text=True,
@@ -68,7 +70,7 @@ def get_changed_files_since(ref: str, root: Path) -> set[str]:
     # 4. Get untracked files.
     try:
         res = subprocess.run(
-            ["git", "ls-files", "--others", "--exclude-standard"],
+            ["git", *_SAFE_GIT_CONFIG, "ls-files", "--others", "--exclude-standard"],
             cwd=git_toplevel,
             capture_output=True,
             text=True,
diff --git a/src/wardline/core/legis.py b/src/wardline/core/legis.py
index 87144974..fe23fcb9 100644
--- a/src/wardline/core/legis.py
+++ b/src/wardline/core/legis.py
@@ -190,6 +190,9 @@ def project_finding(finding: Finding) -> dict[str, Any]:
     }
 
 
+_SAFE_GIT_CONFIG = ("-c", "core.fsmonitor=false")
+
+
 def _git_tree_sha(root: Path) -> str | None:
     """The committed tree object SHA (``git rev-parse HEAD^{tree}``), or None.
 
@@ -199,7 +202,7 @@ def _git_tree_sha(root: Path) -> str | None:
     """
     try:
         rev = subprocess.run(
-            ["git", "rev-parse", "HEAD^{tree}"],
+            ["git", *_SAFE_GIT_CONFIG, "rev-parse", "HEAD^{tree}"],
             cwd=root,
             capture_output=True,
             text=True,
@@ -215,7 +218,7 @@ def _git_repo_root(root: Path) -> Path | None:
     """The containing git repository root, or None when unavailable."""
     try:
         rev = subprocess.run(
-            ["git", "rev-parse", "--show-toplevel"],
+            ["git", *_SAFE_GIT_CONFIG, "rev-parse", "--show-toplevel"],
             cwd=root,
             capture_output=True,
             text=True,
diff --git a/tests/unit/core/test_delta.py b/tests/unit/core/test_delta.py
index 5b16c7af..9d0ca7ba 100644
--- a/tests/unit/core/test_delta.py
+++ b/tests/unit/core/test_delta.py
@@ -43,8 +43,24 @@ def run_dispatch(args, **kwargs):
     res = get_changed_files_since("HEAD~1", root)
 
     assert res == {"foo.py", "bar.py", "baz.py"}
-    assert mock_run.call_args_list[1].args[0] == ["git", "rev-parse", "--verify", "--end-of-options", "HEAD~1"]
-    assert mock_run.call_args_list[2].args[0] == ["git", "diff", "--name-only", "abc123", "--"]
+    assert mock_run.call_args_list[1].args[0] == [
+        "git",
+        "-c",
+        "core.fsmonitor=false",
+        "rev-parse",
+        "--verify",
+        "--end-of-options",
+        "HEAD~1",
+    ]
+    assert mock_run.call_args_list[2].args[0] == [
+        "git",
+        "-c",
+        "core.fsmonitor=false",
+        "diff",
+        "--name-only",
+        "abc123",
+        "--",
+    ]
 
 
 @patch("subprocess.run")