On Fri, Feb 03 2017 at 5:06am -0500,
Christoph Hellwig <hch@xxxxxx> wrote:
> .. at least for unprivilegued users. Before we called into the SCSI
> ioctl code to allow excemptions for a few SCSI passthrough ioctls,
> but this is pretty unsafe and except for this call dm knows nothing
> about SCSI ioctls. As SCSI the SCSI ioctl code is made optionally
> now we really don't want to drag it in for DM, and the exception is
> not very useful anyway.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>
> Note: this should go into the block tree, as that's where
> scsi_verify_blk_ioctl becomes optional.
>
> ---
> drivers/md/dm.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 9e958bc94fed..adc9dcfd5e9c 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -465,13 +465,16 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
>
> if (r > 0) {
> /*
> - * Target determined this ioctl is being issued against
> - * a logical partition of the parent bdev; so extra
> - * validation is needed.
> + * Target determined this ioctl is being issued against a
> + * subset of the parent bdev; require extra privilegues.
> */
> - r = scsi_verify_blk_ioctl(NULL, cmd);
> - if (r)
> + if (!capable(CAP_SYS_RAWIO)) {
> + printk_ratelimited(KERN_WARNING
> + "%s: sending ioctl %x to DM device!\n",
> + current->comm, cmd);
> + r = -ENOIOCTLCMD;
> goto out;
> + }
> }
>
> r = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
> --
> 2.11.0
>
Would prefer to see the use of DMERR_LIMIT() or DMWARN_LIMIT() as those
wrappers provide error message consistency across DM core and DM
targets. Also, would make sense to say: "sending ioctl %x to DM device
without required privilege (CAP_SYS_RAWIO)."
(you have a couple s/privilegue/privilege typos)
And this patch will need Paolo's ack before being staged.
Otherwise, look good:
Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
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