Message ID | 20230123142123.58870-1-duoming@zju.edu.cn |
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State | New |
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[2620:137:e000::1:20]) by mx.google.com with ESMTP id g7-20020a056a0023c700b0058150179c5bsi24341871pfc.26.2023.01.23.06.27.16; Mon, 23 Jan 2023 06:27:29 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232256AbjAWOVn (ORCPT <rfc822;liningstudo@gmail.com> + 99 others); Mon, 23 Jan 2023 09:21:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230377AbjAWOVl (ORCPT <rfc822;linux-kernel@vger.kernel.org>); Mon, 23 Jan 2023 09:21:41 -0500 X-Greylist: delayed 47329 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 23 Jan 2023 06:21:38 PST Received: from zg8tmtyylji0my4xnjeumjiw.icoremail.net (zg8tmtyylji0my4xnjeumjiw.icoremail.net [162.243.161.220]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 8BF2D2004D; Mon, 23 Jan 2023 06:21:38 -0800 (PST) Received: from ubuntu.localdomain (unknown [112.254.167.99]) by mail-app4 (Coremail) with SMTP id cS_KCgDnet3ml85jwadpCg--.20831S2; Mon, 23 Jan 2023 22:21:34 +0800 (CST) From: Duoming Zhou <duoming@zju.edu.cn> To: linux-media@vger.kernel.org, sean@mess.org Cc: maximlevitsky@gmail.com, mchehab@kernel.org, linux-kernel@vger.kernel.org, Duoming Zhou <duoming@zju.edu.cn> Subject: [PATCH v2] media: rc: Fix use-after-free bugs caused by ene_tx_irqsim() Date: Mon, 23 Jan 2023 22:21:23 +0800 Message-Id: <20230123142123.58870-1-duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: cS_KCgDnet3ml85jwadpCg--.20831S2 X-Coremail-Antispam: 1UD129KBjvJXoW7WFyrJF17Kw1rAw4xuF17Jrb_yoW8Ww47p3 y8GFWSkry8Jr42vFnrXw4ku3W5Zws5J34UuryxW3yjvrn5GFy5AF9Yqa4jqay5AFyxZFZF vr4rXF4fCFn8uFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkS14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY02Avz4vE14v_Xryl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r 4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY 6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUe_M3DUUUU X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAgcEAVZdtdU8lAAjsg X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: <linux-kernel.vger.kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1755774064865500250?= X-GMAIL-MSGID: =?utf-8?q?1755823786650181640?= |
Series |
[v2] media: rc: Fix use-after-free bugs caused by ene_tx_irqsim()
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Commit Message
Duoming Zhou
Jan. 23, 2023, 2:21 p.m. UTC
When the ene device is detaching, function ene_remove() will
be called. But there is no function to cancel tx_sim_timer
in ene_remove(), the timer handler ene_tx_irqsim() could race
with ene_remove(). As a result, the UAF bugs could happen,
the process is shown below.
(cleanup routine) | (timer routine)
| mod_timer(&dev->tx_sim_timer, ..)
ene_remove() | (wait a time)
kfree(dev) //FREE |
| ene_tx_irqsim()
| dev->hw_lock //USE
| ene_tx_sample(dev) //USE
Fix by adding del_timer_sync(&dev->tx_sim_timer) in ene_remove(),
The tx_sim_timer could stop before ene device is deallocated.
What's more, the timer can call ene_tx_sample() which can write
to the io ports. So we should put rc_unregister_device() and
del_timer_sync(&dev->tx_sim_timer) before release_region() in
ene_remove().
Fixes: 9ea53b74df9c ("V4L/DVB: STAGING: remove lirc_ene0100 driver")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
Changes in v2:
- Move rc_unregister_device() and del_timer_sync() before release_region().
drivers/media/rc/ene_ir.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Comments
On Mon, Jan 23, 2023 at 10:21:23PM +0800, Duoming Zhou wrote: > When the ene device is detaching, function ene_remove() will > be called. But there is no function to cancel tx_sim_timer > in ene_remove(), the timer handler ene_tx_irqsim() could race > with ene_remove(). As a result, the UAF bugs could happen, > the process is shown below. > > (cleanup routine) | (timer routine) > | mod_timer(&dev->tx_sim_timer, ..) > ene_remove() | (wait a time) > kfree(dev) //FREE | > | ene_tx_irqsim() > | dev->hw_lock //USE > | ene_tx_sample(dev) //USE > > Fix by adding del_timer_sync(&dev->tx_sim_timer) in ene_remove(), > The tx_sim_timer could stop before ene device is deallocated. > > What's more, the timer can call ene_tx_sample() which can write > to the io ports. So we should put rc_unregister_device() and > del_timer_sync(&dev->tx_sim_timer) before release_region() in > ene_remove(). > > Fixes: 9ea53b74df9c ("V4L/DVB: STAGING: remove lirc_ene0100 driver") > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > --- > Changes in v2: > - Move rc_unregister_device() and del_timer_sync() before release_region(). > > drivers/media/rc/ene_ir.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c > index e09270916fb..2864360af9e 100644 > --- a/drivers/media/rc/ene_ir.c > +++ b/drivers/media/rc/ene_ir.c > @@ -1112,8 +1112,9 @@ static void ene_remove(struct pnp_dev *pnp_dev) > spin_unlock_irqrestore(&dev->hw_lock, flags); > > free_irq(dev->irq, dev); > - release_region(dev->hw_io, ENE_IO_SIZE); > rc_unregister_device(dev->rdev); > + del_timer_sync(&dev->tx_sim_timer); > + release_region(dev->hw_io, ENE_IO_SIZE); > kfree(dev); > } I'm sorry, I think there might be a problem there: the irq is freed before the rc device is unregistered. The rx receiver is disabled with ene_rx_disable() before rc_unregister_device() is called, which means it can be enabled again if a process opens /dev/lirc0 between ene_rx_disable() and rc_unregister_device(). ene_remove() should call rc_unregister_device() and del_timer_sync() before anything else. Sean
Hello, On Mon, 23 Jan 2023 15:13:40 +0000 Sean Young wrote: > On Mon, Jan 23, 2023 at 10:21:23PM +0800, Duoming Zhou wrote: > > When the ene device is detaching, function ene_remove() will > > be called. But there is no function to cancel tx_sim_timer > > in ene_remove(), the timer handler ene_tx_irqsim() could race > > with ene_remove(). As a result, the UAF bugs could happen, > > the process is shown below. > > > > (cleanup routine) | (timer routine) > > | mod_timer(&dev->tx_sim_timer, ..) > > ene_remove() | (wait a time) > > kfree(dev) //FREE | > > | ene_tx_irqsim() > > | dev->hw_lock //USE > > | ene_tx_sample(dev) //USE > > > > Fix by adding del_timer_sync(&dev->tx_sim_timer) in ene_remove(), > > The tx_sim_timer could stop before ene device is deallocated. > > > > What's more, the timer can call ene_tx_sample() which can write > > to the io ports. So we should put rc_unregister_device() and > > del_timer_sync(&dev->tx_sim_timer) before release_region() in > > ene_remove(). > > > > Fixes: 9ea53b74df9c ("V4L/DVB: STAGING: remove lirc_ene0100 driver") > > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > > --- > > Changes in v2: > > - Move rc_unregister_device() and del_timer_sync() before release_region(). > > > > drivers/media/rc/ene_ir.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c > > index e09270916fb..2864360af9e 100644 > > --- a/drivers/media/rc/ene_ir.c > > +++ b/drivers/media/rc/ene_ir.c > > @@ -1112,8 +1112,9 @@ static void ene_remove(struct pnp_dev *pnp_dev) > > spin_unlock_irqrestore(&dev->hw_lock, flags); > > > > free_irq(dev->irq, dev); > > - release_region(dev->hw_io, ENE_IO_SIZE); > > rc_unregister_device(dev->rdev); > > + del_timer_sync(&dev->tx_sim_timer); > > + release_region(dev->hw_io, ENE_IO_SIZE); > > kfree(dev); > > } > > I'm sorry, I think there might be a problem there: the irq is freed before > the rc device is unregistered. > > The rx receiver is disabled with ene_rx_disable() before rc_unregister_device() > is called, which means it can be enabled again if a process opens /dev/lirc0 > between ene_rx_disable() and rc_unregister_device(). > > ene_remove() should call rc_unregister_device() and del_timer_sync() before > anything else. Thank your for your time and suggestions, I understand it. Best regards, Duoming Zhou
diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c index e09270916fb..2864360af9e 100644 --- a/drivers/media/rc/ene_ir.c +++ b/drivers/media/rc/ene_ir.c @@ -1112,8 +1112,9 @@ static void ene_remove(struct pnp_dev *pnp_dev) spin_unlock_irqrestore(&dev->hw_lock, flags); free_irq(dev->irq, dev); - release_region(dev->hw_io, ENE_IO_SIZE); rc_unregister_device(dev->rdev); + del_timer_sync(&dev->tx_sim_timer); + release_region(dev->hw_io, ENE_IO_SIZE); kfree(dev); }