From: Eli Zaretskii <eliz@gnu.org>
To: Amritpal Singh <icy.amrit@gmail.com>
Cc: 63832-done@debbugs.gnu.org
Subject: bug#63832: fix failed inflation of .el.gz archives due to passing empty buffer to inflate()
Date: Thu, 08 Jun 2023 12:43:11 +0300 [thread overview]
Message-ID: <83cz262ssw.fsf@gnu.org> (raw)
In-Reply-To: <CAAtEfCFd+EFE-+vjybiGnTPuNaSdK5BuwoUC4Qo8sK6qW3LAhQ@mail.gmail.com> (message from Amritpal Singh on Fri, 2 Jun 2023 12:21:07 +0530)
> From: Amritpal Singh <icy.amrit@gmail.com>
> Date: Fri, 2 Jun 2023 12:21:07 +0530
>
> Compile emacs with the system's gzip program set to `pigz`.
> Run emacs and then `M-x eww RET`
>
> Expected behavior:
> Enter URL prompt in mini-buffer
>
> Actual behavior:
> hashing failed '/usr/share/emacs/30.0.50/lisp/gnus/gnus.el.gz'
>
> Report:
> The bug has been reproduced on emacs version 29.0.91 and HEAD which
> seems to be at 30.0.50.
> Later, a copy of the aforementioned file was saved somewhere else and
> the program was uninstalled. Then emacs was recompiled with system's
> gzip program set to GNU gzip and the initial steps were repeated and
> the expected behavior was the result.
> This lead to believing either that there's a bug with how zlib's
> `inflate()` handles archives or emacs code was having an issue with
> archives files.
>
> The hashes for gz archives generated with different programs were as follows
> > md5sum gnus-gzip.el.gz
> edb3d0ffba7f19ff1d4ec3f889609e8a gnus-gzip.el.gz
> > md5sum gnus.el.gz
> 985deaaec6a5845ac8d6bd9648957b50 gnus.el.gz
>
> And when uncompressing these archives, the resulting file was the same
> and the hash for the files was the same (omitted for brevity).
>
> Now after logging some code in $EMACS_REPO/src/decompress.c, it was
> learned that in the pigz specific case, `inflate()` was returning
> Z_BUF_ERROR(-5) which is an indicator for zstream's either `avail_in`
> or `avail_out` fields are 0.
>
> Observing the code in `$EMACS_REPO/src/decompress.c`
> L154:
> } while (!stream.avail_out);
> only checks stream.avail_out and not stream.avail_in which also might
> have been set to 0. A special case here can be constructed where
> `avail_in` is 0, and the code keeps looping even though our input
> buffer is empty and thus causing a Z_BUF_ERROR. Placing a simple check
> for it fixes the bug in pigz's gz archives case and does not cause any
> issue with gzip archives.
>
> A patch with a simple fix is attached below
Thanks, installed on the master branch, and closing the bug.
next prev parent reply other threads:[~2023-06-08 9:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 6:51 bug#63832: fix failed inflation of .el.gz archives due to passing empty buffer to inflate() Amritpal Singh
2023-06-02 12:04 ` Eli Zaretskii
2023-06-08 9:43 ` Eli Zaretskii [this message]
2023-08-01 5:41 ` bug#63832: fix failed inflation of .el.gz archives due to passing Ulrich Mueller
2023-08-01 11:11 ` Eli Zaretskii
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