From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A236C37A487; Thu, 20 Aug 2026 15:35:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787240148; cv=none; b=u1ffOpAZNcsywF1E7zL4yIqBrgom07wQozoDedW+BnIt4KuUXqvmx7flC381OuSU/8iN0NsL4whltq8faF+prVEy7K4udELRnmQoFcvik3coTjjIwahjJrxFdVteGnGD1xD0x/0uH9ltBQoRu5I9r/Y1U8M61t9D+7k8OcTzOmo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787240148; c=relaxed/simple; bh=v2ZdfvVE+c8VBDgC5YLyRGPciNOUQrYqWOZ2REhb+YQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CBs0JpANZV+F3XP5aqWWR1GHAoqOLDP9w6ro0M5X0SXaO3bt6Y94FMp3w4bWRhISwCOLpcVkovR+GwEISqMNiKK3Xwir6Vzb/LP2nPAVikOiLOzxddR8Ta3tYyP7lWdH5BVN5RsAs0sMtTgd9eps0r2Y2iU0NjVB9hR4ln3r2mw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=kV9u1/nd; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=vkUK/vyJ; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="kV9u1/nd"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="vkUK/vyJ" Date: Thu, 20 Aug 2026 17:35:44 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1787240145; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+T9ZPpgIMi97gDw4k1I8pfsAVB2S1vNUsKoFuKa2Wuo=; b=kV9u1/nd7wDk0B3P/LZIKdRPgtn8VlaQ4eX9vjvnxoYEXnIuC3yhcQRQipQGbNU3YWTg8r iLX0Sh3p44huKGmLrfVvptdL+RvAbfYLiuGcmwabamU7ZdWTdH0sZrtimqpCA+KnXZ8fB7 XKKsNxfE5haGrHiL1QH5Pl+D/Dx0BzQ5K7gdcvI5jzZOzOQa64UrwIC9BFE4/r8feDBf6+ 2YCf0Qx1cy3YYR5+UZttn92c1eZ9ZnkHArfqc5yh/OHb9Ez4bg+3ney/0XGgTGTPsTYfOi Xjv9C4GPUzNoYUHwsYajNepa14uSylw/Mlp5cBUsRy5FnD623upReo1lKxEsVQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1787240145; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+T9ZPpgIMi97gDw4k1I8pfsAVB2S1vNUsKoFuKa2Wuo=; b=vkUK/vyJESvmU3hZAFMBiQN0S0NT34oAzLEKjCcmntr4hu/wp0kw71VhN8HZDj3tLJCidT ZuQI0bJ431zyCQCQ== From: Sebastian Andrzej Siewior To: Petr Mladek Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Andy Shevchenko , Kees Cook , Rasmus Villemoes , Sergey Senozhatsky , Steven Rostedt , Tycho Andersen Subject: Re: [PATCH 0/2] vsprintf: Don't leak pointers Message-ID: <20260820153544.PKYwu35j@linutronix.de> References: <20260814144854.746840-1-bigeasy@linutronix.de> <20260814125647.3e10a3441ca204855b135a5e@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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 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