| commit | 1204e1a824c34071019fe106348eaa6d88f9528d | [log] [tgz] |
|---|---|---|
| author | Patrick Steinhardt <ps@pks.im> | Mon Apr 15 13:30:41 2024 +0200 |
| committer | Johannes Schindelin <johannes.schindelin@gmx.de> | Wed Apr 17 02:17:40 2024 +0200 |
| tree | d24cf82e28ee297d30768695875cc6f536ab90fa | |
| parent | 8c9c051bef3db0fe267f3fb6a1dab293c5f23b38 [diff] |
builtin/clone: refuse local clones of unsafe repositories
When performing a local clone of a repository we end up either copying
or hardlinking the source repository into the target repository. This is
significantly more performant than if we were to use git-upload-pack(1)
and git-fetch-pack(1) to create the new repository and preserves both
disk space and compute time.
Unfortunately though, performing such a local clone of a repository that
is not owned by the current user is inherently unsafe:
- It is possible that source files get swapped out underneath us while
we are copying or hardlinking them. While we do perform some checks
here to assert that we hardlinked the expected file, they cannot
reliably thwart time-of-check-time-of-use (TOCTOU) style races. It
is thus possible for an adversary to make us copy or hardlink
unexpected files into the target directory.
Ideally, we would address this by starting to use openat(3P),
fstatat(3P) and friends. Due to platform compatibility with Windows
we cannot easily do that though. Furthermore, the scope of these
fixes would likely be quite broad and thus not fit for an embargoed
security release.
- Even if we handled TOCTOU-style races perfectly, hardlinking files
owned by a different user into the target repository is not a good
idea in general. It is possible for an adversary to rewrite those
files to contain whatever data they want even after the clone has
completed.
Address these issues by completely refusing local clones of a repository
that is not owned by the current user. This reuses our existing infra we
have in place via `ensure_valid_ownership()` and thus allows a user to
override the safety guard by adding the source repository path to the
"safe.directory" configuration.
This addresses CVE-2024-32020.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see Documentation/giteveryday.txt for a useful minimum set of commands, and Documentation/git-<commandname>.txt for documentation of each command. If git has been correctly installed, then the tutorial can also be read with man gittutorial or git help tutorial, and the documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt (man gitcvs-migration or git help cvs-migration if git is installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message string translations (localization l10) should see po/README.md (a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email with just “subscribe git” in the body to majordomo@vger.kernel.org (not the Git list). The mailing list archives are available at https://lore.kernel.org/git/, http://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the “What's cooking” reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name “git” was given by Linus Torvalds when he wrote the very first version. He described the tool as “the stupid content tracker” and the name as (depending on your mood):