From: Niklas Cassel niklas.cassel@wdc.com

A user space process should not need the CAP_SYS_ADMIN capability set in order to perform a BLKREPORTZONE ioctl.

Getting the zone report is required in order to get the write pointer. Neither read() nor write() requires CAP_SYS_ADMIN, so it is reasonable that a user space process that can read/write from/to the device, also can get the write pointer. (Since e.g. writes have to be at the write pointer.)

Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls") Signed-off-by: Niklas Cassel niklas.cassel@wdc.com Reviewed-by: Damien Le Moal damien.lemoal@wdc.com Reviewed-by: Aravind Ramesh aravind.ramesh@wdc.com Reviewed-by: Adam Manzanares a.manzanares@samsung.com Reviewed-by: Himanshu Madhani himanshu.madhani@oracle.com Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Cc: stable@vger.kernel.org # v4.10+ --- Changes since v4: -Picked up additional Reviewed-by tag. -Corrected Damien's email.

block/blk-zoned.c | 3 --- 1 file changed, 3 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 8a60dbeb44be..1d0c76c18fc5 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -360,9 +360,6 @@ int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode, if (!blk_queue_is_zoned(q)) return -ENOTTY;

- if (!capable(CAP_SYS_ADMIN)) - return -EACCES; - if (copy_from_user(&rep, argp, sizeof(struct blk_zone_report))) return -EFAULT;