# \[PATCH v5 0/2\] allow blk-zoned ioctls without CAP\_SYS\_ADMIN - Subsystems: BLOCK LAYER, ZONED BLOCK DEVICE (BLOCK LAYER), THE REST - Maintainers: Jens Axboe, Damien Le Moal, Linus Torvalds - Series: 2 patches touching 1 file, +0/-6 - Status: LANDED - Landed in mainline. - Revision v5 (5 revisions archived). - List: linux-block - 4 messages, 2 authors - Page: https://ratatoskr.run/linux-block/2021/08/1474776/t ## \[PATCH v5 0/2\] allow blk-zoned ioctls without CAP\_SYS\_ADMIN - From: Niklas Cassel \ - Date: 2021-08-11 11:05:25 - Message: https://ratatoskr.run/linux-block/2021/08/1474776.md ```text From: Niklas Cassel Allow the following blk-zoned ioctls: BLKREPORTZONE, BLKRESETZONE, BLKOPENZONE, BLKCLOSEZONE, and BLKFINISHZONE to be performed without CAP_SYS_ADMIN. Neither read() nor write() requires CAP_SYS_ADMIN, and considering the close relationship between read()/write() and these ioctls, there is no reason to require CAP_SYS_ADMIN for these ioctls either. Changes since v4: -Picked up additional Reviewed-by tags. -Corrected Damien's email in patch 2/2. Changes since v3: -Picked up additional Reviewed-by tags. Changes since v2: -Dropped the FMODE_READ check from patch 2/2. Changes since v1: -Picked up tags from Damien. -Added fixes tags. Niklas Cassel (2): blk-zoned: allow zone management send operations without CAP_SYS_ADMIN blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN block/blk-zoned.c | 6 ------ 1 file changed, 6 deletions(-) -- 2.31.1 ``` ## \[PATCH v5 1/2\] blk-zoned: allow zone management send operations without CAP\_SYS\_ADMIN - From: Niklas Cassel \ - Date: 2021-08-11 11:05:30 - Message: https://ratatoskr.run/linux-block/2021/08/1474777.md ```text From: Niklas Cassel 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 Reviewed-by: Damien Le Moal Reviewed-by: Aravind Ramesh Reviewed-by: Adam Manzanares Reviewed-by: Himanshu Madhani Reviewed-by: Johannes Thumshirn Cc: # v4.10+ --- Changes since v4: -Picked up additional Reviewed-by tag. 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 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; -- 2.31.1 ``` ## \[PATCH v5 2/2\] blk-zoned: allow BLKREPORTZONE without CAP\_SYS\_ADMIN - From: Niklas Cassel \ - Date: 2021-08-11 11:05:38 - Message: https://ratatoskr.run/linux-block/2021/08/1474778.md ```text From: Niklas Cassel 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 Reviewed-by: Damien Le Moal Reviewed-by: Aravind Ramesh Reviewed-by: Adam Manzanares Reviewed-by: Himanshu Madhani Reviewed-by: Johannes Thumshirn Cc: # 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; -- 2.31.1 ``` ## Re: \[PATCH v5 0/2\] allow blk-zoned ioctls without CAP\_SYS\_ADMIN - From: Jens Axboe \ - Date: 2021-08-24 16:13:47 - Message: https://ratatoskr.run/linux-block/2021/08/1487246.md ```text On 8/11/21 5:05 AM, Niklas Cassel wrote: > From: Niklas Cassel > > Allow the following blk-zoned ioctls: BLKREPORTZONE, BLKRESETZONE, > BLKOPENZONE, BLKCLOSEZONE, and BLKFINISHZONE to be performed without > CAP_SYS_ADMIN. > > Neither read() nor write() requires CAP_SYS_ADMIN, and considering > the close relationship between read()/write() and these ioctls, there > is no reason to require CAP_SYS_ADMIN for these ioctls either. Applied, thanks. -- Jens Axboe ```