linux-kernel - Re: [PATCH] gfs2: avoid %pS in pr_err() fallback to prevent vsnprintf crash

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAHc6FU5qWAY=aUjZ+YwwjteWCanNYFZW_xpDbWHkJV99qo=W=g@mail.gmail.com>
Date: Wed, 17 Sep 2025 12:33:56 +0200
From: Andreas Gruenbacher <agruenba@...hat.com>
To: Kriish Sharma <kriish.sharma2006@...il.com>
Cc: gfs2@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	syzbot+fa7122891ab9e0bbc6a7@...kaller.appspotmail.com
Subject: Re: [PATCH] gfs2: avoid %pS in pr_err() fallback to prevent vsnprintf crash

On Tue, Sep 16, 2025 at 11:12 PM Kriish Sharma
<kriish.sharma2006@...il.com> wrote:
> While debugging a syzbot report, I found that the %pS format in
> dump_holder() can trigger a crash when we end up in the pr_err()
> fallback path. This happens because %pS goes through symbol resolution
> inside vsnprintf, and in this case that isn’t always safe.

I'm unconvinced -- when and why is %pS not safe to use?

Thanks,
Andreas