Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755318AbbGPBO3 (ORCPT ); Wed, 15 Jul 2015 21:14:29 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56413 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755135AbbGPBMD (ORCPT ); Wed, 15 Jul 2015 21:12:03 -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 245/251] mac80211: prevent possible crypto tx tailroom corruption Date: Wed, 15 Jul 2015 18:09:26 -0700 Message-Id: <1437008972-9140-246-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: 2383 Lines: 67 3.19.8-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Kazior commit ab499db80fcf07c18e4053f91a619500f663e90e upstream. There was a possible race between ieee80211_reconfig() and ieee80211_delayed_tailroom_dec(). This could result in inability to transmit data if driver crashed during roaming or rekeying and subsequent skbs with insufficient tailroom appeared. This race was probably never seen in the wild because a device driver would have to crash AND recover within 0.5s which is very unlikely. I was able to prove this race exists after changing the delay to 10s locally and crashing ath10k via debugfs immediately after GTK rekeying. In case of ath10k the counter went below 0. This was harmless but other drivers which actually require tailroom (e.g. for WEP ICV or MMIC) could end up with the counter at 0 instead of >0 and introduce insufficient skb tailroom failures because mac80211 would not resize skbs appropriately anymore. Fixes: 8d1f7ecd2af5 ("mac80211: defer tailroom counter manipulation when roaming") Signed-off-by: Michal Kazior Signed-off-by: Johannes Berg Signed-off-by: Kamal Mostafa --- net/mac80211/main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 6ab99da..05ebd07 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -249,6 +249,7 @@ static void ieee80211_restart_work(struct work_struct *work) { struct ieee80211_local *local = container_of(work, struct ieee80211_local, restart_work); + struct ieee80211_sub_if_data *sdata; /* wait for scan work complete */ flush_workqueue(local->workqueue); @@ -257,6 +258,8 @@ static void ieee80211_restart_work(struct work_struct *work) "%s called with hardware scan in progress\n", __func__); rtnl_lock(); + list_for_each_entry(sdata, &local->interfaces, list) + flush_delayed_work(&sdata->dec_tailroom_needed_wk); ieee80211_scan_cancel(local); ieee80211_reconfig(local); rtnl_unlock(); -- 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/