From b338d8cee138c2fd98f788ec295f8f2f719f53c2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bern=C3=A1t=20G=C3=A1bor?= Date: Fri, 9 Jan 2026 09:49:49 -0800 Subject: [PATCH] fix: resolve TOCTOU vulnerabilities in app_data and lock directory creation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use atomic os.makedirs(..., exist_ok=True) operations instead of check-then-act pattern to prevent symlink-based TOCTOU attacks. Reported by: tsigouris007 Signed-off-by: Bernát Gábor --- docs/changelog/3013.bugfix.rst | 1 + src/virtualenv/app_data/__init__.py | 11 +++++------ src/virtualenv/util/lock.py | 7 +++---- 3 files changed, 9 insertions(+), 10 deletions(-) create mode 100644 docs/changelog/3013.bugfix.rst diff --git a/src/virtualenv/app_data/__init__.py b/src/virtualenv/app_data/__init__.py index d7f148023..7a9d38e92 100644 --- a/src/virtualenv/app_data/__init__.py +++ b/src/virtualenv/app_data/__init__.py @@ -36,12 +36,11 @@ def make_app_data(folder, **kwargs): if is_read_only: return ReadOnlyAppData(folder) - if not os.path.isdir(folder): - try: - os.makedirs(folder) - LOGGER.debug("created app data folder %s", folder) - except OSError as exception: - LOGGER.info("could not create app data folder %s due to %r", folder, exception) + try: + os.makedirs(folder, exist_ok=True) + LOGGER.debug("created app data folder %s", folder) + except OSError as exception: + LOGGER.info("could not create app data folder %s due to %r", folder, exception) if os.access(folder, os.W_OK): return AppDataDiskFolder(folder) diff --git a/src/virtualenv/util/lock.py b/src/virtualenv/util/lock.py index b250e032f..82c8eed65 100644 --- a/src/virtualenv/util/lock.py +++ b/src/virtualenv/util/lock.py @@ -17,9 +17,8 @@ class _CountedFileLock(FileLock): def __init__(self, lock_file) -> None: parent = os.path.dirname(lock_file) - if not os.path.isdir(parent): - with suppress(OSError): - os.makedirs(parent) + with suppress(OSError): + os.makedirs(parent, exist_ok=True) super().__init__(lock_file) self.count = 0 @@ -117,7 +116,7 @@ def _lock_file(self, lock, no_block=False): # noqa: FBT002 # a lock, but that lock might then become expensive, and it's not clear where that lock should live. # Instead here we just ignore if we fail to create the directory. with suppress(OSError): - os.makedirs(str(self.path)) + os.makedirs(str(self.path), exist_ok=True) try: lock.acquire(0.0001)