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block: move CAP_SYS_ADMIN check in blkdev_roset()

Check for CAP_SYS_ADMIN before calling into the driver, similar to
blkdev_flushbuf().  This is safer and can spare a check in the driver.

(Currently BLKROSET is overridden by md and rbd, rbd is missing the
check.  md has the check, but it covers a lot more than BLKROSET.)

Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Ilya Dryomov 2017-10-18 14:38:38 +02:00 committed by Jens Axboe
parent 351499a172
commit bb749b31c2
1 changed files with 3 additions and 2 deletions

View File

@ -443,11 +443,12 @@ static int blkdev_roset(struct block_device *bdev, fmode_t mode,
{
int ret, n;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
if (!is_unrecognized_ioctl(ret))
return ret;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (get_user(n, (int __user *)arg))
return -EFAULT;
set_device_ro(bdev, n);