From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dave Jones , Sasha Levin , Ming Lei Subject: [ 09/56] sysfs: handle failure path correctly for readdir() Date: Tue, 2 Apr 2013 15:49:36 -0700 Message-Id: <20130402224712.935625545@linuxfoundation.org> In-Reply-To: <20130402224711.840825715@linuxfoundation.org> References: <20130402224711.840825715@linuxfoundation.org> List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei commit e5110f411d2ee35bf8d202ccca2e89c633060dca upstream. In case of 'if (filp->f_pos == 0 or 1)' of sysfs_readdir(), the failure from filldir() isn't handled, and the reference counter of the sysfs_dirent object pointed by filp->private_data will be released without clearing filp->private_data, so use after free bug will be triggered later. This patch returns immeadiately under the situation for fixing the bug, and it is reasonable to return from readdir() when filldir() fails. Reported-by: Dave Jones Tested-by: Sasha Levin Signed-off-by: Ming Lei Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -917,6 +917,8 @@ static int sysfs_readdir(struct file * f ino = parent_sd->s_ino; if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) filp->f_pos++; + else + return 0; } if (filp->f_pos == 1) { if (parent_sd->s_parent) @@ -925,6 +927,8 @@ static int sysfs_readdir(struct file * f ino = parent_sd->s_ino; if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) filp->f_pos++; + else + return 0; } mutex_lock(&sysfs_mutex); for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);