[PATCH v2 1/2] blk-zoned: allow zone management send operations without CAP_SYS_ADMIN

From: Niklas Cassel
Date: Tue Jun 01 2021 - 04:39:36 EST


From: Niklas Cassel <niklas.cassel@xxxxxxx>

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 <niklas.cassel@xxxxxxx>
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.10+
---
Changes since v1:
- Pick up tag from Damien.
- Add fixes tag and CC stable.

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(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 250cb76ee615..0789e6e9f7db 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -349,9 +349,6 @@ 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;

--
2.31.1