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Mon, 30 Mar 2026 09:17:08 -0700 (PDT) Date: Mon, 30 Mar 2026 18:17:06 +0200 From: Petr Mladek To: Josh Law Cc: Steven Rostedt , Andy Shevchenko , Rasmus Villemoes , Sergey Senozhatsky , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] lib/vsprintf: fix OOB write in vbin_printf() when size is zero Message-ID: References: <20260324224940.50508-1-objecting@objecting.org> <20260324224940.50508-3-objecting@objecting.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=us-ascii Content-Disposition: inline In-Reply-To: <20260324224940.50508-3-objecting@objecting.org> On Tue 2026-03-24 22:49:38, Josh Law wrote: > When vbin_printf() is called with size==0, end equals bin_buf and > the else branch writes end[-1], which is one byte before the buffer. > > Guard the write so it only happens when the buffer is non-empty. > > Signed-off-by: Josh Law Great catch! There is only one in-tree user and it never passes size=0 so there was no overflow in the reality. But better be on the safe side. Reviewed-by: Petr Mladek Best Regards, Petr