linux-hardened/fs/sysfs
Tejun Heo f5c16f29bf sysfs: make sure read buffer is zeroed
13c589d5b0 ("sysfs: use seq_file when reading regular files")
switched sysfs from custom read implementation to seq_file to enable
later transition to kernfs.  After the change, the buffer passed to
->show() is acquired through seq_get_buf(); unfortunately, this
introduces a subtle behavior change.  Before the commit, the buffer
passed to ->show() was always zero as it was allocated using
get_zeroed_page().  Because seq_file doesn't clear buffers on
allocation and neither does seq_get_buf(), after the commit, depending
on the behavior of ->show(), we may end up exposing uninitialized data
to userland thus possibly altering userland visible behavior and
leaking information.

Fix it by explicitly clearing the buffer.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Ron <ron@debian.org>
Fixes: 13c589d5b0 ("sysfs: use seq_file when reading regular files")
Cc: stable <stable@vger.kernel.org> # 3.13+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-20 10:15:53 +09:00
..
dir.c kernfs: implement kernfs_get_parent(), kernfs_name/path() and friends 2014-02-07 16:05:35 -08:00
file.c sysfs: make sure read buffer is zeroed 2014-05-20 10:15:53 +09:00
group.c sysfs: create bin_attributes under the requested group 2014-02-15 12:14:55 -08:00
Kconfig kernfs: add CONFIG_KERNFS 2014-02-07 16:08:57 -08:00
Makefile sysfs, kernfs: move inode code to fs/kernfs/inode.c 2013-11-29 17:55:10 -08:00
mount.c kernfs, sysfs, cgroup: restrict extra perm check on open to sysfs 2014-05-13 13:21:40 +02:00
symlink.c kernfs: s/sysfs/kernfs/ in constants 2013-12-11 17:39:20 -08:00
sysfs.h kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly 2013-12-11 15:28:36 -08:00