From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933682Ab0JSJYx (ORCPT ); Tue, 19 Oct 2010 05:24:53 -0400 Received: from minas.ics.muni.cz ([147.251.4.40]:42205 "EHLO minas.ics.muni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932393Ab0JSJYw (ORCPT ); Tue, 19 Oct 2010 05:24:52 -0400 From: Jiri Slaby To: jkosina@suse.cz Cc: alan@signal11.us, linux-input@vger.kernel.org, jirislaby@gmail.com, linux-kernel@vger.kernel.org, Jiri Slaby Subject: [PATCH 1/1] HID: hidraw, fix window in hidraw_release Date: Tue, 19 Oct 2010 11:24:45 +0200 Message-Id: <1287480285-5335-1-git-send-email-jslaby@suse.cz> X-Mailer: git-send-email 1.7.3.1 In-Reply-To: <20101009144026.c37f8d25.ospite@studenti.unina.it> References: <20101009144026.c37f8d25.ospite@studenti.unina.it> X-Muni-Spam-TestIP: 147.251.48.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (minas.ics.muni.cz [147.251.4.35]); Tue, 19 Oct 2010 11:24:47 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is a window between hidraw_table check and its dereference. In that window, the device may be unplugged and removed form the system and we will then dereference NULL. Lock that place properly so that either we get NULL and jump out or we can work with real pointer. Signed-off-by: Jiri Slaby --- drivers/hid/hidraw.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index 925992f..6d81be3 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -218,9 +218,13 @@ static int hidraw_release(struct inode * inode, struct file * file) unsigned int minor = iminor(inode); struct hidraw *dev; struct hidraw_list *list = file->private_data; + int ret; - if (!hidraw_table[minor]) - return -ENODEV; + mutex_lock(&minors_lock); + if (!hidraw_table[minor]) { + ret = -ENODEV; + goto unlock; + } list_del(&list->node); dev = hidraw_table[minor]; @@ -233,10 +237,12 @@ static int hidraw_release(struct inode * inode, struct file * file) kfree(list->hidraw); } } - + ret = 0; +unlock: + mutex_unlock(&minors_lock); kfree(list); - return 0; + return ret; } static long hidraw_ioctl(struct file *file, unsigned int cmd, -- 1.7.3.1