diff options
| author |   Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2016-12-07 14:44:31 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-07 17:10:00 -0800 |
| commit | 5c7e9ccd91b90d87029261f8856294ee51934cab (patch) | |
| tree | 5bb12cbd8f271f71c1a7141ca7d86916ab92d71a | |
| parent | Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| download | linux-dev-5c7e9ccd91b90d87029261f8856294ee51934cab.tar.xz linux-dev-5c7e9ccd91b90d87029261f8856294ee51934cab.zip | |
zram: restrict add/remove attributes to root only
zram hot_add sysfs attribute is a very 'special' attribute - reading
from it creates a new uninitialized zram device. This file, by a
mistake, can be read by a 'normal' user at the moment, while only root
must be able to create a new zram device, therefore hot_add attribute
must have S_IRUSR mode, not S_IRUGO.
[akpm@linux-foundation.org: s/sence/sense/, reflow comment to use 80 cols]
Fixes: 6566d1a32bf72 ("zram: add dynamic device add/remove functionality")
Link: http://lkml.kernel.org/r/20161205155845.20129-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Steven Allen <steven@stebalien.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 5163c8f918cb..5497f7fc44d0 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1413,8 +1413,14 @@ static ssize_t hot_remove_store(struct class *class, return ret ? ret : count; } +/* + * NOTE: hot_add attribute is not the usual read-only sysfs attribute. In a + * sense that reading from this file does alter the state of your system -- it + * creates a new un-initialized zram device and returns back this device's + * device_id (or an error code if it fails to create a new device). + */ static struct class_attribute zram_control_class_attrs[] = { - __ATTR_RO(hot_add), + __ATTR(hot_add, 0400, hot_add_show, NULL), __ATTR_WO(hot_remove), __ATTR_NULL, }; |