Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936275Ab3DHKJ2 (ORCPT ); Mon, 8 Apr 2013 06:09:28 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42851 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935744Ab3DHJwI (ORCPT ); Mon, 8 Apr 2013 05:52:08 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Ming Lei , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 056/102] sysfs: fix race between readdir and lseek Date: Mon, 8 Apr 2013 10:50:11 +0100 Message-Id: <1365414657-29191-57-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1365414657-29191-1-git-send-email-luis.henriques@canonical.com> References: <1365414657-29191-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1985 Lines: 62 3.5.7.10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei commit 991f76f837bf22c5bb07261cfd86525a0a96650c upstream. While readdir() is running, lseek() may set filp->f_pos as zero, then may leave filp->private_data pointing to one sysfs_dirent object without holding its reference counter, so the sysfs_dirent object may be used after free in next readdir(). This patch holds inode->i_mutex to avoid the problem since the lock is always held in readdir path. Reported-by: Dave Jones Tested-by: Sasha Levin Cc: Signed-off-by: Ming Lei Signed-off-by: Greg Kroah-Hartman [ luis: backported to 3.5: removed usage of file_inode() ] Signed-off-by: Luis Henriques --- fs/sysfs/dir.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 2ee0864..8777436 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -1063,10 +1063,21 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) return 0; } +static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_path.dentry->d_inode; + loff_t ret; + + mutex_lock(&inode->i_mutex); + ret = generic_file_llseek(file, offset, whence); + mutex_unlock(&inode->i_mutex); + + return ret; +} const struct file_operations sysfs_dir_operations = { .read = generic_read_dir, .readdir = sysfs_readdir, .release = sysfs_dir_release, - .llseek = generic_file_llseek, + .llseek = sysfs_dir_llseek, }; -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/