From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH] hvmloader/smbios: Change strncpy to memcpy for anchor strings. Date: Tue, 24 Sep 2013 11:11:32 +0100 Message-ID: References: <52417A0202000078000F5CD4@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VOPas-0006Km-Qo for xen-devel@lists.xenproject.org; Tue, 24 Sep 2013 10:11:47 +0000 Received: by mail-wg0-f41.google.com with SMTP id l18so3248911wgh.4 for ; Tue, 24 Sep 2013 03:11:45 -0700 (PDT) In-Reply-To: <52417A0202000078000F5CD4@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich , Paul Durrant Cc: Andrew Cooper , xen-devel List-Id: xen-devel@lists.xenproject.org On 24/09/2013 10:39, "Jan Beulich" wrote: >>> - strncpy(ep->anchor_string, "_SM_", 4); >>> + memcpy(ep->anchor_string, "_SM_", sizeof(ep->anchor_string)); >> >> Why the change from 4 to sizeof(ep->anchor_string) here (and similar below)? >> Setting the copy length based on the size of the destination rather than the >> source seems like the wrong thing to do. > > One can argue either way here: > - passing the destination's size guarantees no memory corruption > - passing the source's size guarantees no uninitialized memory > > Since the structure fields involved here aren't going to change, > either way is fine imo. As was the unadorned number 4, imo. -- Keir