From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423032AbcE3VLZ (ORCPT ); Mon, 30 May 2016 17:11:25 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:53242 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422965AbcE3VLI (ORCPT ); Mon, 30 May 2016 17:11:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Marcel Holtmann Subject: [PATCH 4.6 040/100] Bluetooth: vhci: Fix race at creating hci device Date: Mon, 30 May 2016 13:49:35 -0700 Message-Id: <20160530204909.736619726@linuxfoundation.org> X-Mailer: git-send-email 2.8.3 In-Reply-To: <20160530204908.422037419@linuxfoundation.org> References: <20160530204908.422037419@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit c7c999cb18da88a881e10e07f0724ad0bfaff770 upstream. hci_vhci driver creates a hci device object dynamically upon each HCI_VENDOR_PKT write. Although it checks the already created object and returns an error, it's still racy and may build multiple hci_dev objects concurrently when parallel writes are performed, as the device tracks only a single hci_dev object. This patch introduces a mutex to protect against the concurrent device creations. Signed-off-by: Takashi Iwai Signed-off-by: Marcel Holtmann Signed-off-by: Greg Kroah-Hartman --- drivers/bluetooth/hci_vhci.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) --- a/drivers/bluetooth/hci_vhci.c +++ b/drivers/bluetooth/hci_vhci.c @@ -50,6 +50,7 @@ struct vhci_data { wait_queue_head_t read_wait; struct sk_buff_head readq; + struct mutex open_mutex; struct delayed_work open_timeout; }; @@ -87,12 +88,15 @@ static int vhci_send_frame(struct hci_de return 0; } -static int vhci_create_device(struct vhci_data *data, __u8 opcode) +static int __vhci_create_device(struct vhci_data *data, __u8 opcode) { struct hci_dev *hdev; struct sk_buff *skb; __u8 dev_type; + if (data->hdev) + return -EBADFD; + /* bits 0-1 are dev_type (BR/EDR or AMP) */ dev_type = opcode & 0x03; @@ -151,6 +155,17 @@ static int vhci_create_device(struct vhc return 0; } +static int vhci_create_device(struct vhci_data *data, __u8 opcode) +{ + int err; + + mutex_lock(&data->open_mutex); + err = __vhci_create_device(data, opcode); + mutex_unlock(&data->open_mutex); + + return err; +} + static inline ssize_t vhci_get_user(struct vhci_data *data, struct iov_iter *from) { @@ -191,11 +206,6 @@ static inline ssize_t vhci_get_user(stru case HCI_VENDOR_PKT: cancel_delayed_work_sync(&data->open_timeout); - if (data->hdev) { - kfree_skb(skb); - return -EBADFD; - } - opcode = *((__u8 *) skb->data); skb_pull(skb, 1); @@ -320,6 +330,7 @@ static int vhci_open(struct inode *inode skb_queue_head_init(&data->readq); init_waitqueue_head(&data->read_wait); + mutex_init(&data->open_mutex); INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout); file->private_data = data;