From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753580AbdDJVgJ (ORCPT ); Mon, 10 Apr 2017 17:36:09 -0400 Received: from mail-pf0-f180.google.com ([209.85.192.180]:34327 "EHLO mail-pf0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752045AbdDJVgG (ORCPT ); Mon, 10 Apr 2017 17:36:06 -0400 Date: Mon, 10 Apr 2017 14:36:04 -0700 From: Matthias Kaehlcke To: Johannes Berg , "David S . Miller" , Felix Fietkau Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Grant Grundler Subject: Re: [PATCH v2] cfg80211: Fix array-bounds warning in fragment copy Message-ID: <20170410213604.GB28657@google.com> References: <20170327195822.123034-1-mka@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170327195822.123034-1-mka@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org El Mon, Mar 27, 2017 at 12:58:22PM -0700 Matthias Kaehlcke ha dit: > __ieee80211_amsdu_copy_frag intentionally initializes a pointer to > array[-1] to increment it later to valid values. clang rightfully > generates an array-bounds warning on the initialization statement. > > Initialize the pointer to array[0] and change the algorithm from > increment before to increment after consume. > > Signed-off-by: Matthias Kaehlcke > --- > net/wireless/util.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/net/wireless/util.c b/net/wireless/util.c > index 68e5f2ecee1a..52795ae5337f 100644 > --- a/net/wireless/util.c > +++ b/net/wireless/util.c > @@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame, > int offset, int len) > { > struct skb_shared_info *sh = skb_shinfo(skb); > - const skb_frag_t *frag = &sh->frags[-1]; > + const skb_frag_t *frag = &sh->frags[0]; > struct page *frag_page; > void *frag_ptr; > int frag_len, frag_size; > @@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame, > > while (offset >= frag_size) { > offset -= frag_size; > - frag++; > frag_page = skb_frag_page(frag); > frag_ptr = skb_frag_address(frag); > frag_size = skb_frag_size(frag); > + frag++; > } > > frag_ptr += offset; > @@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct sk_buff *frame, > len -= cur_len; > > while (len > 0) { > - frag++; > frag_len = skb_frag_size(frag); > cur_len = min(len, frag_len); > __frame_add_frag(frame, skb_frag_page(frag), > skb_frag_address(frag), cur_len, frag_len); > len -= cur_len; > + frag++; > } > } > Ping, any feedback on this patch? Thanks Matthias