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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Kees Cook <kees@kernel.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Tycho Andersen <tycho@tycho.pizza>
Subject: Re: [PATCH 0/2] vsprintf: Don't leak pointers
Date: Thu, 20 Aug 2026 17:35:44 +0200	[thread overview]
Message-ID: <20260820153544.PKYwu35j@linutronix.de> (raw)
In-Reply-To: <aocdGcA6TYe5ascV@pathway.suse.cz>

On 2026-08-20 17:28:25 [+0200], Petr Mladek wrote:
> On Fri 2026-08-14 12:56:47, Andrew Morton wrote:
> > On Fri, 14 Aug 2026 16:48:52 +0200 Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:
> > 
> > > It is possible to leak pointers via %ps without KALLSYMS enabled.
> > > With KALLSYMS pointers can be leaked if they can not be resolved.
> > > 
> > > The tiny series has two patches, one for each issue.
> > > 
> > 
> > Thanks.
> > 
> > fwiw, Sashiko flagged a few possible issues:
> > 	https://sashiko.dev/#/patchset/20260814144854.746840-1-bigeasy@linutronix.de
> 
> Sashiko basically complains about that this might make
> dump_stack(), panics, and oopses useless on systems without KALLSYMS
> which is typical on embedded systems.
> 
> IMHO, it is a good point. What about using default_pointer() resp. %p
> as the fallback? It would allow to see the pointers with
> "no_hash_pointers" kernel parameter.

I didn't repost it yet. But this is what I did locally. #1 takes
no_hash_pointers into consideration and #2 is just a comment _why_ we
"leak" the actual pointer.

> Best Regards,
> Petr

Sebastian

      reply	other threads:[~2026-08-20 15:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-14 14:48 Sebastian Andrzej Siewior
2026-08-14 14:48 ` [PATCH 1/2] vsprintf: Don't leak pointers for %ps without KALLSYMS enabled Sebastian Andrzej Siewior
2026-08-15  8:58   ` Andy Shevchenko
2026-08-20 14:24     ` Sebastian Andrzej Siewior
2026-08-20 15:40       ` Petr Mladek
2026-08-14 14:48 ` [PATCH 2/2] kallsyms: Don't leak pointers for unresolved symbols Sebastian Andrzej Siewior
2026-08-14 19:08   ` Bradley Morgan
2026-08-14 19:56 ` [PATCH 0/2] vsprintf: Don't leak pointers Andrew Morton
2026-08-20 15:28   ` Petr Mladek
2026-08-20 15:35     ` Sebastian Andrzej Siewior [this message]

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