Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755293AbbGPB0D (ORCPT ); Wed, 15 Jul 2015 21:26:03 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56190 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932131AbbGPBLk (ORCPT ); Wed, 15 Jul 2015 21:11:40 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Michal Kazior , Johannes Berg , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 205/251] cfg80211: ignore netif running state when changing iftype Date: Wed, 15 Jul 2015 18:08:46 -0700 Message-Id: <1437008972-9140-206-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437008972-9140-1-git-send-email-kamal@canonical.com> References: <1437008972-9140-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3044 Lines: 81 3.19.8-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Kazior commit 6cbfb1bb66e4e85da5db78e8ff429a85bd84ce64 upstream. It was possible for mac80211 to be coerced into an unexpected flow causing sdata union to become corrupted. Station pointer was put into sdata->u.vlan.sta memory location while it was really master AP's sdata->u.ap.next_beacon. This led to station entry being later freed as next_beacon before __sta_info_flush() in ieee80211_stop_ap() and a subsequent invalid pointer dereference crash. The problem was that ieee80211_ptr->use_4addr wasn't cleared on interface type changes. This could be reproduced with the following steps: # host A and host B have just booted; no # wpa_s/hostapd running; all vifs are down host A> iw wlan0 set type station host A> iw wlan0 set 4addr on host A> printf 'interface=wlan0\nssid=4addrcrash\nchannel=1\nwds_sta=1' > /tmp/hconf host A> hostapd -B /tmp/conf host B> iw wlan0 set 4addr on host B> ifconfig wlan0 up host B> iw wlan0 connect -w hostAssid host A> pkill hostapd # host A crashed: [ 127.928192] BUG: unable to handle kernel NULL pointer dereference at 00000000000006c8 [ 127.929014] IP: [] __sta_info_flush+0xac/0x158 ... [ 127.934578] [] ieee80211_stop_ap+0x139/0x26c [ 127.934578] [] ? dump_trace+0x279/0x28a [ 127.934578] [] __cfg80211_stop_ap+0x84/0x191 [ 127.934578] [] cfg80211_stop_ap+0x3f/0x58 [ 127.934578] [] nl80211_stop_ap+0x1b/0x1d [ 127.934578] [] genl_family_rcv_msg+0x259/0x2b5 Note: This isn't a revert of f8cdddb8d61d ("cfg80211: check iface combinations only when iface is running") as far as functionality is considered because b6a550156bc ("cfg80211/mac80211: move more combination checks to mac80211") moved the logic somewhere else already. Fixes: f8cdddb8d61d ("cfg80211: check iface combinations only when iface is running") Signed-off-by: Michal Kazior Signed-off-by: Johannes Berg Signed-off-by: Kamal Mostafa --- net/wireless/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/wireless/util.c b/net/wireless/util.c index 5488c36..da1d372 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -900,7 +900,7 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev, ntype == NL80211_IFTYPE_P2P_CLIENT)) return -EBUSY; - if (ntype != otype && netif_running(dev)) { + if (ntype != otype) { dev->ieee80211_ptr->use_4addr = false; dev->ieee80211_ptr->mesh_id_up_len = 0; wdev_lock(dev->ieee80211_ptr); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/