From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755025AbdDMRFW (ORCPT ); Thu, 13 Apr 2017 13:05:22 -0400 Received: from mail-pg0-f47.google.com ([74.125.83.47]:33260 "EHLO mail-pg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753425AbdDMRFS (ORCPT ); Thu, 13 Apr 2017 13:05:18 -0400 From: Matthias Kaehlcke To: Johannes Berg , "David S . Miller" , Felix Fietkau Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, grundler@chromium.org, Greg Hackmann , Michael Davidson , Matthias Kaehlcke Subject: [PATCH v2] cfg80211: Fix array-bounds warning in fragment copy Date: Thu, 13 Apr 2017 10:05:04 -0700 Message-Id: <20170413170504.110612-1-mka@chromium.org> X-Mailer: git-send-email 2.12.2.715.g7642488e1d-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __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 --- Note: Resent to include linux-wireless in cc 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++; } } -- 2.12.2.715.g7642488e1d-goog