From nobody Sun Apr 19 05:32:18 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F276C433EF for ; Tue, 5 Jul 2022 13:38:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230461AbiGENio (ORCPT ); Tue, 5 Jul 2022 09:38:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229802AbiGENi3 (ORCPT ); Tue, 5 Jul 2022 09:38:29 -0400 Received: from zju.edu.cn (spam.zju.edu.cn [61.164.42.155]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1B96C7D1F3; Tue, 5 Jul 2022 05:59:34 -0700 (PDT) Received: from ubuntu.localdomain (unknown [10.190.65.210]) by mail-app2 (Coremail) with SMTP id by_KCgAnzUHrNMRivCY+Aw--.58122S2; Tue, 05 Jul 2022 20:56:20 +0800 (CST) From: Duoming Zhou To: linux-hams@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ralf@linux-mips.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, Duoming Zhou Subject: [PATCH net v2] net: rose: fix UAF bug caused by rose_t0timer_expiry Date: Tue, 5 Jul 2022 20:56:10 +0800 Message-Id: <20220705125610.77971-1-duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: by_KCgAnzUHrNMRivCY+Aw--.58122S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ar1ftFyktw4DJryUAr1xuFg_yoW8uryrpF WYk343Grs3tw4UXFW8XFn7Zw4Ygw4DJry3Wr1xuFWSy3Z7Jr4YvF1kKFW8uF4xZFWkCFWa gr1kGry5AwnFqF7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkF1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW0oVCq3wA2z4x0Y4vEx4A2 jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52 x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWU GwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI4 8JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCF04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv 6cx26r4fKr1UJr1l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGw C20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48J MIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMI IF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E 87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x0JUdHUDUUUUU= X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAgoCAVZdtaiRogAtsD Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" There are UAF bugs caused by rose_t0timer_expiry(). The root cause is that del_timer() could not stop the timer handler that is running and there is no synchronization. One of the race conditions is shown below: (thread 1) | (thread 2) | rose_device_event | rose_rt_device_down | rose_remove_neigh rose_t0timer_expiry | rose_stop_t0timer(rose_neigh) ... | del_timer(&neigh->t0timer) | kfree(rose_neigh) //[1]FREE neigh->dce_mode //[2]USE | The rose_neigh is deallocated in position [1] and use in position [2]. The crash trace triggered by POC is like below: BUG: KASAN: use-after-free in expire_timers+0x144/0x320 Write of size 8 at addr ffff888009b19658 by task swapper/0/0 ... Call Trace: dump_stack_lvl+0xbf/0xee print_address_description+0x7b/0x440 print_report+0x101/0x230 ? expire_timers+0x144/0x320 kasan_report+0xed/0x120 ? expire_timers+0x144/0x320 expire_timers+0x144/0x320 __run_timers+0x3ff/0x4d0 run_timer_softirq+0x41/0x80 __do_softirq+0x233/0x544 ... This patch changes rose_stop_ftimer() and rose_stop_t0timer() in rose_remove_neigh() to del_timer_sync() in order that the timer handler could be finished before the resources such as rose_neigh and so on are deallocated. As a result, the UAF bugs could be mitigated. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Duoming Zhou --- Changes in v2: - v2: Use del_timer_sync to stop timer in rose_remove_neigh. net/rose/rose_route.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index fee6409c2bb..eb0b8197ac8 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -227,8 +227,8 @@ static void rose_remove_neigh(struct rose_neigh *rose_n= eigh) { struct rose_neigh *s; =20 - rose_stop_ftimer(rose_neigh); - rose_stop_t0timer(rose_neigh); + del_timer_sync(&rose_neigh->ftimer); + del_timer_sync(&rose_neigh->t0timer); =20 skb_queue_purge(&rose_neigh->queue); =20 --=20 2.17.1