Re: [PATCH] mingw: do not crash on open(NULL, ...)

From: Erik Faye-Lund <kusmabite@gmail.com>
Date: Sep 23, 2010, 17:59 UTC
Message-ID: <AANLkTinJ4kKRsKO6HyqQH4Oy12E1mdqCXxPb2z+59818@mail.gmail.com>
In-Reply-To: <1285263325-2016-1-git-send-email-kusmabite@gmail.com>

On Thu, Sep 23, 2010 at 10:35 AM, Erik Faye-Lund <kusmabite@gmail.com> wrote:

> Since open() already sets errno correctly for the NULL-case, let's just
> avoid the problematic strcmp.
>
> Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>

I guess I should add a comment as to why this patch is needed:

This seems to be the culprit for issue 523 in the msysGit issue tracker: http://code.google.com/p/msysgit/issues/detail?id=523

fetch_and_setup_pack_index() apparently pass a NULL-pointer to parse_pack_index(), which in turn pass it to check_packed_git_idx(), which again pass it to open(). This all looks intentional to my (http.c-untrained) eye.

The code in mingw_open was introduced in commit 3e4a1ba (by Johannes Sixt), and the lack of a NULL-check looks like a simple oversight.