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Thu, 20 Aug 2026 08:40:59 -0700 (PDT) Date: Thu, 20 Aug 2026 17:40:57 +0200 From: Petr Mladek To: Sebastian Andrzej Siewior Cc: Andy Shevchenko , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Andrew Morton , Kees Cook , Rasmus Villemoes , Sergey Senozhatsky , Steven Rostedt , Tycho Andersen Subject: Re: [PATCH 1/2] vsprintf: Don't leak pointers for %ps without KALLSYMS enabled Message-ID: References: <20260814144854.746840-1-bigeasy@linutronix.de> <20260814144854.746840-2-bigeasy@linutronix.de> <20260820142426.Q3y-RHVx@linutronix.de> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260820142426.Q3y-RHVx@linutronix.de> On Thu 2026-08-20 16:24:26, Sebastian Andrzej Siewior wrote: > On 2026-08-15 11:58:03 [+0300], Andy Shevchenko wrote: > > On Fri, Aug 14, 2026 at 04:48:53PM +0200, Sebastian Andrzej Siewior wrote: > > > The "%ps" format modifier prints the name of the symbol which is more > > > valuable in terms of debugging and does not leak the actual pointer. > > > > > > Without KALLSYMS it will leak the pointer which is not intended. The > > > default policy for pointers is to print a hashed value and not to leak > > > the actual pointer. > > > > > > Print "(unknown)" for any symbol resolution witout KALLSYMS enabled. > > > > Hmm... I would expect some test cases to be added/modified. > > No bot complained so far, so maybe not ;) It seems that we really do not have test cases for this. I guess that it is because it is so tricky with the various fallbacks, ... The existing test cases for %p are tricky as well. As a result they are an infinite source of problems ;-) Best Regards, Petr