Re: Git Bug Report: out of memory using git tag

From: Jeff King <peff@peff.net>
Date: Nov 2, 2022, 07:39 UTC
Message-ID: <Y2IeqOT5Ao1Qa0Zl@coredump.intra.peff.net>
In-Reply-To: <38d50c30-c6a3-5989-6e01-47c5467d9d6b@gmail.com>

On Tue, Nov 01, 2022 at 08:41:55PM -0400, Philippe Blain wrote:

Show 17 quoted lines

> > The issue isn't unique to pgp signatures; the problem is in the parsing
> > done by ref-filter's find_subpos(), so any signature type exhibits the
> > problem. At the end of that function we do:
> > 
> >       *nonsiglen = sigstart - buf;
> > 
> > but "buf" has moved beyond "sigstart". Presumably because it uses
> > strstr() to look for end-of-line in buf. Since there isn't one before
> > the signature begins, we go to the end of the signature.
> > 
> > The bug bisects to 9f75ce3d8f (ref-filter: handle CRLF at end-of-line
> > more gracefully, 2020-10-29). Before then, I think our loop was careful
> > about moving past the start of the signature. Author cc'd.
> > 
> 
> Thanks for letting me know, and for the simple reproducer, that's very useful.
> I'll try to find time to fix that this week, but can't promise anything.

After sleeping on it, I think I fully understand what's going on. There are actually _two_ bugs, but they are closely related. ;)

Here are patches which fix them both. I may be setting a new record for the ratio of commit message lines to changed code. But it took me a while to figure out what was going on, so I wanted to explain it fully.

  [1/2]: ref-filter: fix parsing of signatures without blank lines
  [2/2]: ref-filter: fix parsing of signatures with CRLF and no body

 ref-filter.c            |  8 ++++----
 t/t6300-for-each-ref.sh | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 4 deletions(-)

-Peff