From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933843AbaLBTxe (ORCPT ); Tue, 2 Dec 2014 14:53:34 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:46566 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932365AbaLBTVl (ORCPT ); Tue, 2 Dec 2014 14:21:41 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Johannes Berg , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 054/121] mac80211: fix use-after-free in defragmentation Date: Tue, 2 Dec 2014 11:18:53 -0800 Message-Id: <1417548000-1794-55-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1417548000-1794-1-git-send-email-kamal@canonical.com> References: <1417548000-1794-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt12 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg commit b8fff407a180286aa683d543d878d98d9fc57b13 upstream. Upon receiving the last fragment, all but the first fragment are freed, but the multicast check for statistics at the end of the function refers to the current skb (the last fragment) causing a use-after-free bug. Since multicast frames cannot be fragmented and we check for this early in the function, just modify that check to also do the accounting to fix the issue. Reported-by: Yosef Khyal Signed-off-by: Johannes Berg Signed-off-by: Kamal Mostafa --- net/mac80211/rx.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 2b0debb..7b9e78a 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1647,11 +1647,14 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) sc = le16_to_cpu(hdr->seq_ctrl); frag = sc & IEEE80211_SCTL_FRAG; - if (likely((!ieee80211_has_morefrags(fc) && frag == 0) || - is_multicast_ether_addr(hdr->addr1))) { - /* not fragmented */ + if (likely(!ieee80211_has_morefrags(fc) && frag == 0)) + goto out; + + if (is_multicast_ether_addr(hdr->addr1)) { + rx->local->dot11MulticastReceivedFrameCount++; goto out; } + I802_DEBUG_INC(rx->local->rx_handlers_fragments); if (skb_linearize(rx->skb)) @@ -1744,10 +1747,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) out: if (rx->sta) rx->sta->rx_packets++; - if (is_multicast_ether_addr(hdr->addr1)) - rx->local->dot11MulticastReceivedFrameCount++; - else - ieee80211_led_rx(rx->local); + ieee80211_led_rx(rx->local); return RX_CONTINUE; } -- 1.9.1