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prevent out-of-repo access when manipulating references. by Byron · Pull Request #2134 · gitpython-developers/GitPython · GitHub
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prevent out-of-repo access when manipulating references. #2134

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Merged
Byron merged 2 commits into from
Apr 28, 2026
Merged

prevent out-of-repo access when manipulating references. #2134

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25ba54d
prevent out-of-repo access when manipulating references.
codex Apr 28, 2026
4af8463
address review feedback and CI failures
codex Apr 28, 2026
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6 changes: 4 additions & 2 deletions git/refs/log.py
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Expand Up @@ -4,7 +4,6 @@
__all__ = ["RefLog", "RefLogEntry"]

from mmap import mmap
import os.path as osp
import re
import time as _time

Expand Down Expand Up @@ -212,8 +211,11 @@ def path(cls, ref: "SymbolicReference") -> str:

:param ref:
:class:`~git.refs.symbolic.SymbolicReference` instance
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:raise ValueError:
If `ref.path` is invalid or escapes the repository's reflog directory.
"""
return osp.join(ref.repo.git_dir, "logs", to_native_path(ref.path))
return to_native_path(ref._get_validated_reflog_path(ref.repo, ref.path))

@classmethod
def iter_entries(cls, stream: Union[str, "BytesIO", mmap]) -> Iterator[RefLogEntry]:
Expand Down
7 changes: 5 additions & 2 deletions git/refs/remote.py
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Expand Up @@ -58,17 +58,20 @@ def delete(cls, repo: "Repo", *refs: "RemoteReference", **kwargs: Any) -> None:
`kwargs` are given for comparability with the base class method as we
should not narrow the signature.
"""
for ref in refs:
cls._check_ref_name_valid(ref.path)

repo.git.branch("-d", "-r", *refs)
# The official deletion method will ignore remote symbolic refs - these are
# generally ignored in the refs/ folder. We don't though and delete remainders
# manually.
for ref in refs:
try:
os.remove(os.path.join(repo.common_dir, ref.path))
os.remove(cls._get_validated_path(repo.common_dir, ref.path))
except OSError:
pass
try:
os.remove(os.path.join(repo.git_dir, ref.path))
os.remove(cls._get_validated_path(repo.git_dir, ref.path))
except OSError:
pass
# END for each ref
Expand Down
37 changes: 31 additions & 6 deletions git/refs/symbolic.py
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Expand Up @@ -110,6 +110,32 @@ def name(self) -> str:
def abspath(self) -> PathLike:
return join_path_native(_git_dir(self.repo, self.path), self.path)

@staticmethod
def _get_validated_path(base: PathLike, path: PathLike) -> str:
path = os.fspath(path)
base_path = os.path.realpath(os.fspath(base))
abs_path = os.path.realpath(os.path.join(base_path, path))
try:
common_path = os.path.commonpath([base_path, abs_path])
except ValueError as e:
raise ValueError("Reference path %r escapes the repository" % path) from e
if os.path.normcase(common_path) != os.path.normcase(base_path):
raise ValueError("Reference path %r escapes the repository" % path)
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return abs_path

@classmethod
def _get_validated_ref_path(cls, repo: "Repo", path: PathLike) -> str:
"""Return the absolute filesystem path for a ref after validating it."""
cls._check_ref_name_valid(path)
ref_path = os.fspath(path)
return cls._get_validated_path(_git_dir(repo, ref_path), ref_path)

@classmethod
def _get_validated_reflog_path(cls, repo: "Repo", path: PathLike) -> str:
"""Return the absolute filesystem path for a reflog after validating it."""
cls._check_ref_name_valid(path)
return cls._get_validated_path(os.path.join(repo.git_dir, "logs"), path)

@classmethod
def _get_packed_refs_path(cls, repo: "Repo") -> str:
return os.path.join(repo.common_dir, "packed-refs")
Expand Down Expand Up @@ -485,7 +511,7 @@ def set_reference(
# END handle non-existing
# END retrieve old hexsha

fpath = self.abspath
fpath = self._get_validated_ref_path(self.repo, self.path)
assure_directory_exists(fpath, is_file=True)

lfd = LockedFD(fpath)
Expand Down Expand Up @@ -632,7 +658,7 @@ def delete(cls, repo: "Repo", path: PathLike) -> None:
Alternatively the symbolic reference to be deleted.
"""
full_ref_path = cls.to_full_path(path)
abs_path = os.path.join(repo.common_dir, full_ref_path)
abs_path = cls._get_validated_ref_path(repo, full_ref_path)
if os.path.exists(abs_path):
os.remove(abs_path)
else:
Expand Down Expand Up @@ -695,9 +721,8 @@ def _create(
symbolic reference. Otherwise it will be resolved to the corresponding object
and a detached symbolic reference will be created instead.
"""
git_dir = _git_dir(repo, path)
full_ref_path = cls.to_full_path(path)
abs_ref_path = os.path.join(git_dir, full_ref_path)
abs_ref_path = cls._get_validated_ref_path(repo, full_ref_path)

# Figure out target data.
target = reference
Expand Down Expand Up @@ -789,8 +814,8 @@ def rename(self, new_path: PathLike, force: bool = False) -> "SymbolicReference"
if self.path == new_path:
return self

new_abs_path = os.path.join(_git_dir(self.repo, new_path), new_path)
cur_abs_path = os.path.join(_git_dir(self.repo, self.path), self.path)
new_abs_path = self._get_validated_ref_path(self.repo, new_path)
cur_abs_path = self._get_validated_ref_path(self.repo, self.path)
if os.path.isfile(new_abs_path):
if not force:
# If they point to the same file, it's not an error.
Expand Down
2 changes: 1 addition & 1 deletion git/util.py
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Original file line number Diff line number Diff line change
Expand Up @@ -289,7 +289,7 @@ def join_path(a: PathLike, *p: PathLike) -> PathLike:

if sys.platform == "win32":

def to_native_path_windows(path: PathLike) -> PathLike:
def to_native_path_windows(path: PathLike) -> str:
path = os.fspath(path)
return path.replace("/", "\\")

Expand Down
123 changes: 123 additions & 0 deletions test/test_refs.py
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Expand Up @@ -3,6 +3,7 @@
# This module is part of GitPython and is released under the
# 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/

import contextlib
from itertools import chain
import os.path as osp
from pathlib import Path
Expand All @@ -18,6 +19,7 @@
RefLog,
Reference,
RemoteReference,
Repo,
SymbolicReference,
TagReference,
)
Expand All @@ -29,6 +31,18 @@


class TestRefs(TestBase):
@contextlib.contextmanager
def _repo_with_initial_commit(self, base_dir):
repo_dir = base_dir / "repo"
repo = Repo.init(repo_dir)
(repo_dir / "file.txt").write_text("initial\n", encoding="utf-8")
repo.index.add(["file.txt"])
repo.index.commit("initial")
try:
yield repo
finally:
repo.git.clear_cache()

def test_from_path(self):
# Should be able to create any reference directly.
for ref_type in (Reference, Head, TagReference, RemoteReference):
Expand Down Expand Up @@ -648,6 +662,115 @@ def test_refs_outside_repo(self):
ref_file_name = Path(ref_file.name).name
self.assertRaises(BadName, self.rorepo.commit, f"../../{ref_file_name}")

def test_reference_create_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_path = base_dir / "outside_write.txt"

self.assertRaises(ValueError, Reference.create, repo, "../../../outside_write.txt", "HEAD")
assert not outside_path.exists()

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def test_symbolic_reference_create_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_path = base_dir / "outside_write.txt"

self.assertRaises(ValueError, SymbolicReference.create, repo, "../../outside_write.txt", "HEAD")
assert not outside_path.exists()

def test_symbolic_reference_set_reference_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_path = base_dir / "outside_write.txt"

self.assertRaises(ValueError, SymbolicReference(repo, "../../outside_write.txt").set_reference, "HEAD")
assert not outside_path.exists()

def test_symbolic_reference_rename_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_path = base_dir / "outside_move.txt"
ref = SymbolicReference.create(repo, "SAFE_RENAME_SOURCE", "HEAD")

self.assertRaises(ValueError, ref.rename, "../../outside_move.txt")
assert not outside_path.exists()
assert Path(ref.abspath).is_file()

def test_symbolic_reference_delete_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_path = base_dir / "outside_delete.txt"
outside_path.write_text("do not delete\n", encoding="utf-8")

self.assertRaises(ValueError, SymbolicReference.delete, repo, "../../outside_delete.txt")
assert outside_path.read_text(encoding="utf-8") == "do not delete\n"

def test_symbolic_reference_log_append_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_path = base_dir / "outside_reflog.txt"

ref = SymbolicReference(repo, "../../../outside_reflog.txt")
self.assertRaises(
ValueError, ref.log_append, Commit.NULL_BIN_SHA, "do not write", repo.head.commit.binsha
)
assert not outside_path.exists()

def test_symbolic_reference_set_reference_rejects_symlink_escape(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
with self._repo_with_initial_commit(base_dir) as repo:
outside_dir = base_dir / "outside_refs"
outside_dir.mkdir()
outside_path = outside_dir / "escaped"

refs_heads_dir = Path(repo.common_dir) / "refs" / "heads"
refs_heads_dir.mkdir(parents=True, exist_ok=True)
symlink_path = refs_heads_dir / "link_out"
try:
symlink_path.symlink_to(outside_dir, target_is_directory=True)
except (OSError, NotImplementedError) as ex:
self.skipTest("symlinks unavailable on this platform: %s" % ex)
if osp.realpath(symlink_path / "escaped") == osp.abspath(symlink_path / "escaped"):
self.skipTest("realpath does not resolve directory symlinks on this platform")
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ref = SymbolicReference(repo, "refs/heads/link_out/escaped")
self.assertRaises(ValueError, ref.set_reference, "HEAD")
assert not outside_path.exists()

def test_remote_reference_delete_cleanup_rejects_path_traversal(self):
with tempfile.TemporaryDirectory() as tmp_dir:
base_dir = Path(tmp_dir)
git_dir = base_dir / "repo" / ".git"
git_dir.mkdir(parents=True)
outside_path = base_dir / "outside_remote_delete.txt"
outside_path.write_text("do not delete\n", encoding="utf-8")

class GitStub:
branch_called = False

def branch(self, *args):
self.branch_called = True

class RepoStub:
pass

repo = RepoStub()
repo.git = GitStub()
repo.common_dir = str(git_dir)
repo.git_dir = str(git_dir)
ref = RemoteReference(repo, "../../outside_remote_delete.txt", check_path=False)

self.assertRaises(ValueError, RemoteReference.delete, repo, ref)
assert not repo.git.branch_called
assert outside_path.read_text(encoding="utf-8") == "do not delete\n"

def test_validity_ref_names(self):
"""Ensure ref names are checked for validity.
Expand Down
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