From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932395Ab1KWAek (ORCPT ); Tue, 22 Nov 2011 19:34:40 -0500 Received: from cantor2.suse.de ([195.135.220.15]:42277 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932383Ab1KWAef (ORCPT ); Tue, 22 Nov 2011 19:34:35 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Tue Nov 22 16:25:54 2011 Message-Id: <20111123002553.923715246@clark.kroah.org> User-Agent: quilt/0.48-20.1.2 Date: Tue, 22 Nov 2011 16:25:11 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Johannes Berg , "John W. Linville" Subject: [11/53] mac80211: fix NULL dereference in radiotap code In-Reply-To: <20111123002601.GA14467@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg commit f8d1ccf15568268c76f913b45ecdd33134387f1a upstream. When receiving failed PLCP frames is enabled, there won't be a rate pointer when we add the radiotap header and thus the kernel will crash. Fix this by not assuming the rate pointer is always valid. It's still always valid for frames that have good PLCP though, and that is checked & enforced. This was broken by my commit fc88518916793af8ad6a02e05ff254d95c36d875 Author: Johannes Berg Date: Fri Jul 30 13:23:12 2010 +0200 mac80211: don't check rates on PLCP error frames where I removed the check in this case but didn't take into account that the rate info would be used. Reported-by: Xiaokang Qin Signed-off-by: Johannes Berg Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- net/mac80211/rx.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -140,8 +140,9 @@ ieee80211_add_rx_radiotap_header(struct pos++; /* IEEE80211_RADIOTAP_RATE */ - if (status->flag & RX_FLAG_HT) { + if (!rate || status->flag & RX_FLAG_HT) { /* + * Without rate information don't add it. If we have, * MCS information is a separate field in radiotap, * added below. The byte here is needed as padding * for the channel though, so initialise it to 0. @@ -162,12 +163,14 @@ ieee80211_add_rx_radiotap_header(struct else if (status->flag & RX_FLAG_HT) put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ, pos); - else if (rate->flags & IEEE80211_RATE_ERP_G) + else if (rate && rate->flags & IEEE80211_RATE_ERP_G) put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ, pos); - else + else if (rate) put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ, pos); + else + put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos); pos += 2; /* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */