From patchwork Wed Apr 10 03:53:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Duoming Zhou X-Patchwork-Id: 787666 Received: from zg8tmja2lje4os4yms4ymjma.icoremail.net (zg8tmja2lje4os4yms4ymjma.icoremail.net [206.189.21.223]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8CE2520EB; Wed, 10 Apr 2024 03:53:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=206.189.21.223 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712721205; cv=none; b=SNn5LraKHAsx5Kk6vHlmgK8SzPttVwl8H5FxcSqaOYBCJucQEP4iCbKJUw/Ruct7oCE0fBqbNMdvZ0ei18I5Lg03Gm45ZEetHbcnH/Kd2FNXPnte7oY0tJdNizVFkvWeTEW0UX4TWZkbK+63ZhnRuSP89m5wJVzynOcTAWvo1gg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712721205; c=relaxed/simple; bh=VY1r65IiB4CyR69n168a92EjuLdXbUDvXcgwt9yvfQ4=; h=From:To:Cc:Subject:Date:Message-Id; b=MzNoqnk44WdFdtB4GJ/xJ79VbpJP2jaxupIYtXj4kUVhXy+Yew3Cd7y+YQCFf9eEGhiBHzxKql1UwaFTVVGY5NMCQvb+N9NWpAh+XKs5Fco0oF1L/JaSkGPTYJsstC6D7G6ryXKGR5BJhIbShAiHxkfJumzjJHq/aRW6dAZnf5Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn; spf=pass smtp.mailfrom=zju.edu.cn; arc=none smtp.client-ip=206.189.21.223 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zju.edu.cn Received: from ubuntu.localdomain (unknown [218.12.17.105]) by mail-app3 (Coremail) with SMTP id cC_KCgBnOu0dDRZmZEGBAA--.65136S2; Wed, 10 Apr 2024 11:53:07 +0800 (CST) From: Duoming Zhou To: linux-bluetooth@vger.kernel.org Cc: linux-kernel@vger.kernel.org, luiz.dentz@gmail.com, johan.hedberg@gmail.com, marcel@holtmann.org, Duoming Zhou Subject: [PATCH v2] Bluetooth: Fix use-after-free bug caused by hci_cmd_timeout Date: Wed, 10 Apr 2024 11:53:00 +0800 Message-Id: <20240410035300.21160-1-duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: cC_KCgBnOu0dDRZmZEGBAA--.65136S2 X-Coremail-Antispam: 1UD129KBjvJXoWxJFy3XF48JF4kuF1DJr13Arb_yoW5tr4Dpr Z09ryfArWkXry2yr4xJa18trykuFsIvr9rGrZ2qr1fAwsxK3yjya4jka4jqF17uFyvyFyU WF1DXr9rXFs8Kw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkl14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4U JVW0owA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWU AVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4U MIIF0xvEx4A2jsIEc7CjxVAFwI0_Jr0_GrUvcSsGvfC2KfnxnUUI43ZEXa7VUjuHq7UUUU U== X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAwIGAWYVR5sEWQBQsk Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: When the kernel send a command to the hci device, the hdev->cmd_timer will be scheduled to judge whether is command is timeout. Meanwhile, the user space program uses ioctl(..., HCI_INQUIRY) to inquiry the status of the command, it will wait the reply of the command until the command is timeout. If it is timeout, the req_skb will be deallocated, but req_skb could be dereferenced in hci_cmd_timeout() as well. As a result, the use-after-free bug will happen. One of the scenarios that could trigger the bug is shown below: thread 1 thread2 hci_sock_ioctl() | hci_sock_sendmsg() hci_inquiry() | queue_work(...,&hdev->cmd_work) hci_req_sync() | hci_cmd_work() __hci_req_sync() | queue_delayed_work(...,&hdev->cmd_timer) kfree_skb(hdev->req_skb) | hci_cmd_timeout() | hci_skb_opcode(hdev->req_skb) The KASan report for such a POC is shown below: ================================================================== BUG: KASAN: slab-use-after-free in hci_cmd_timeout+0x3c/0x110 Read of size 2 at addr ffff8880087a1c78 by task kworker/u21:0/131 ... Workqueue: hci0 hci_cmd_timeout Call Trace: dump_stack_lvl+0x84/0xc0 print_address_description+0x78/0x440 print_report+0x11b/0x220 ? pfn_valid+0xe4/0x140 ? __virt_addr_valid+0x7c/0x90 ? hci_cmd_timeout+0x3c/0x110 kasan_report+0xc7/0x100 ? hci_cmd_timeout+0x3c/0x110 hci_cmd_timeout+0x3c/0x110 process_one_work+0x2df/0x610 worker_thread+0x72f/0x870 ? pr_cont_work+0x280/0x280 kthread+0x18a/0x1b0 ? kthread_blkcg+0x50/0x50 ret_from_fork+0x34/0x50 ? kthread_blkcg+0x50/0x50 ret_from_fork_asm+0x11/0x20 Allocated by task 131 on cpu 1 at 45.611537s: kasan_save_track+0x32/0x90 __kasan_slab_alloc+0x4b/0x60 kmem_cache_alloc+0xcb/0x240 skb_clone+0x117/0x170 hci_cmd_work+0x19c/0x2a0 process_one_work+0x2df/0x610 worker_thread+0x72f/0x870 kthread+0x18a/0x1b0 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x11/0x20 Freed by task 135 on cpu 2 at 47.671850s: kasan_save_track+0x32/0x90 kasan_save_free_info+0x40/0x50 poison_slab_object+0x118/0x180 __kasan_slab_free+0x12/0x30 kmem_cache_free+0x92/0x200 __hci_req_sync+0x2e2/0x350 hci_req_sync+0x73/0x90 hci_inquiry+0x1c1/0x350 sock_do_ioctl+0x50/0x1a0 sock_ioctl+0x2ea/0x3b0 __se_sys_ioctl+0x89/0xd0 do_syscall_64+0xc4/0x1b0 entry_SYSCALL_64_after_hwframe+0x62/0x6a ... In order to mitigate the bug, add cancel_delayed_work_sync() in __hci_req_sync() to cancel the cmd_timer before the req_skb is deallocated when the command is timeout. Fixes: 9afee94939e3 ("Bluetooth: Fix memory leak at end of hci requests") Signed-off-by: Duoming Zhou --- Changes in v2: - Call cancel_delayed_work_sync() only if the command is timeout. net/bluetooth/hci_request.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c index 00e02138003..0b002f01816 100644 --- a/net/bluetooth/hci_request.c +++ b/net/bluetooth/hci_request.c @@ -174,6 +174,7 @@ int __hci_req_sync(struct hci_dev *hdev, int (*func)(struct hci_request *req, default: err = -ETIMEDOUT; + cancel_delayed_work_sync(&hdev->cmd_timer); if (hci_status) *hci_status = HCI_ERROR_UNSPECIFIED; break;