[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 27 Dec 2016 20:00:01 +0100
From: Jakub Wilk <jwilk@...lk.net>
To: oss-security@...ts.openwall.com
Subject: Re: tqdm: insecure use of git
>Can you clarify the threat model for this? Our understanding is that
>.git/config is not really a part of a repository that is controlled by a
>remote party, e.g., see the second paragraph of the
>https://git-blame.blogspot.com/2014/12/git-1856-195-205-214-and-221-and.html
>post.
Right; the malicious git repository would have to be created by other means
than "git clone" alone.
The attack scenario I had in mind is:
Alice and Mallory are local users on the same machine.
Mallory creates world-readable /tmp/.git such that running "git log" against
this repository compromises the user's account.
Alice chdirs to /tmp (or maybe even to a subdirectory of /tmp accessible only
to her), and runs a command that uses the tqdm module under the hood. tqdm
executes "git log", which executes Mallory's code.
>Is either (or both) of these a valid interpretation of your report?
>
>1. You are suggesting that there is a security problem in git because the
>risks of an attacker-controlled config file are not documented carefully
>enough. In other words, you want documentation such as
>https://www.kernel.org/pub/software/scm/git/docs/git-config.html to tell the
>user that they must not use a "repository specific configuration file" that is
>writable by an untrusted local user.
No, I don't see this as a problem in git.
>2. You are suggesting that there is a security problem in tqdm because the
>victim is not explicitly being told that they are executing a git command, and
>thus they do not realize that there is a need to verify that they have a safe
>cwd before proceeding.
Yes.
>A. Anyone planning to explicitly enter "git log" from a shell prompt is
>responsible for first verifying that the cwd is safe. It is a known property
>of git that the cwd is critical to security.
Yes.
>B. No third-party product should ever be executing "git log" in an unexpected
>context. Either the user must somehow be aware that a "git log" may be
>executed, or else the product must somehow force the use of a safe local
>directory. Otherwise, a CVE is needed for each such product.
Yes.
--
Jakub Wilk
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
