[v4,1/2] blk-zoned: allow zone management send operations without CAP_SYS_ADMIN

Commit Message

Niklas Cassel Aug. 9, 2021, 9:50 a.m. UTC

From: Niklas Cassel <[e-mail]>

Zone management send operations (BLKRESETZONE, BLKOPENZONE, BLKCLOSEZONE
and BLKFINISHZONE) should be allowed under the same permissions as write().
(write() does not require CAP_SYS_ADMIN).

Additionally, other ioctls like BLKSECDISCARD and BLKZEROOUT only check if
the fd was successfully opened with FMODE_WRITE.
(They do not require CAP_SYS_ADMIN).

Currently, zone management send operations require both CAP_SYS_ADMIN
and that the fd was successfully opened with FMODE_WRITE.

Remove the CAP_SYS_ADMIN requirement, so that zone management send
operations match the access control requirement of write(), BLKSECDISCARD
and BLKZEROOUT.

Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls")
Signed-off-by: Niklas Cassel <[e-mail]>
Reviewed-by: Damien Le Moal <[e-mail]>
Reviewed-by: Aravind Ramesh <[e-mail]>
Reviewed-by: Adam Manzanares <[e-mail]>
Reviewed-by: Himanshu Madhani <[e-mail]>
Cc: [e-mail] # v4.10+
---
Changes since v3:
-Picked up additional Reviewed-by tags.

Note to backporter:
Function was added as blkdev_reset_zones_ioctl() in v4.10.
Function was renamed to blkdev_zone_mgmt_ioctl() in v5.5.
The patch is valid both before and after the function rename.

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

Comments

Johannes Thumshirn Aug. 9, 2021, 9:57 a.m. UTC | #1

On 09/08/2021 11:50, Niklas Cassel wrote:
> From: Niklas Cassel <[e-mail]>
> 
> Zone management send operations (BLKRESETZONE, BLKOPENZONE, BLKCLOSEZONE
> and BLKFINISHZONE) should be allowed under the same permissions as write().
> (write() does not require CAP_SYS_ADMIN).
> 
> Additionally, other ioctls like BLKSECDISCARD and BLKZEROOUT only check if
> the fd was successfully opened with FMODE_WRITE.
> (They do not require CAP_SYS_ADMIN).
> 
> Currently, zone management send operations require both CAP_SYS_ADMIN
> and that the fd was successfully opened with FMODE_WRITE.
> 
> Remove the CAP_SYS_ADMIN requirement, so that zone management send
> operations match the access control requirement of write(), BLKSECDISCARD
> and BLKZEROOUT.
> 
> Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls")
> Signed-off-by: Niklas Cassel <[e-mail]>
> Reviewed-by: Damien Le Moal <[e-mail]>
> Reviewed-by: Aravind Ramesh <[e-mail]>
> Reviewed-by: Adam Manzanares <[e-mail]>
> Reviewed-by: Himanshu Madhani <[e-mail]>
> Cc: [e-mail] # v4.10+
> ---

Looks good,
Reviewed-by: Johannes Thumshirn <[e-mail]>

Patch

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 86fce751bb17..8a60dbeb44be 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -421,9 +421,6 @@  int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
 	if (!blk_queue_is_zoned(q))
 		return -ENOTTY;
 
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-
 	if (!(mode & FMODE_WRITE))
 		return -EBADF;