Re: [PATCH 6/6] sd: add support for TCG OPAL self encrypting disks

Scott Bauer
2017-06-05T21:29:38Z

On Sun, Jun 04, 2017 at 02:42:25PM +0200, Christoph Hellwig wrote:
> Just wire up the generic TCG OPAL infrastructure to the SCSI disk driver
> and the Security In/Out commands.
>
> Note that I don't know of any actual SCSI disks that do support TCG OPAL,
> but this is required to support ATA disks through libata.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/scsi/sd.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> drivers/scsi/sd.h | 2 ++
> 2 files changed, 46 insertions(+)
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index b6bb4e0ce0e3..782f909a223c 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -50,6 +50,7 @@
> #include <linux/string_helpers.h>
> #include <linux/async.h>
> #include <linux/slab.h>
> +#include <linux/sed-opal.h>
> #include <linux/pm_runtime.h>
> #include <linux/pr.h>
> #include <linux/t10-pi.h>
> @@ -643,6 +644,26 @@ static void scsi_disk_put(struct scsi_disk *sdkp)
> mutex_unlock(&sd_ref_mutex);
> }
>
> +#ifdef CONFIG_BLK_SED_OPAL
> +static int sd_sec_submit(void *data, u16 spsp, u8 secp, void *buffer,
> + size_t len, bool send)
> +{
> + struct scsi_device *sdev = data;
> + u8 cdb[12] = { 0, };
> + int ret;
> +
> + cdb[0] = send ? SECURITY_PROTOCOL_OUT : SECURITY_PROTOCOL_IN;
> + cdb[1] = secp;
> + put_unaligned_be16(spsp, &cdb[2]);
> + put_unaligned_be32(len, &cdb[6]);
> +
> + ret = scsi_execute_req(sdev, cdb,
> + send ? DMA_TO_DEVICE : DMA_FROM_DEVICE,
> + buffer, len, NULL, SD_TIMEOUT, SD_MAX_RETRIES, NULL);
> + return ret <= 0 ? ret : -EIO;
> +}
> +#endif /* CONFIG_BLK_SED_OPAL */
> +
> static unsigned char sd_setup_protect_cmnd(struct scsi_cmnd *scmd,
> unsigned int dix, unsigned int dif)
> {
> @@ -1454,6 +1475,9 @@ static int sd_ioctl(struct block_device *bdev, fmode_t mode,
> if (error)
> goto out;
>
> + if (is_sed_ioctl(cmd))
> + return sed_ioctl(sdkp->opal_dev, cmd, p);
> +
> /*
> * Send SCSI addressing ioctls directly to mid level, send other
> * ioctls to block level and then onto mid level if they can't be
> @@ -3014,6 +3038,17 @@ static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
> sdkp->ws10 = 1;
> }
>
> +static void sd_read_security(struct scsi_disk *sdkp, unsigned char *buffer)
> +{
> + struct scsi_device *sdev = sdkp->device;
> +
> + if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE,
> + SECURITY_PROTOCOL_IN) == 1 &&
> + scsi_report_opcode(sdev, buffer, SD_BUF_SIZE,
> + SECURITY_PROTOCOL_OUT) == 1)
> + sdkp->security = 1;
> +}
> +
> /**
> * sd_revalidate_disk - called the first time a new disk is seen,
> * performs disk spin up, read_capacity, etc.
> @@ -3067,6 +3102,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
> sd_read_cache_type(sdkp, buffer);
> sd_read_app_tag_own(sdkp, buffer);
> sd_read_write_same(sdkp, buffer);
> + sd_read_security(sdkp, buffer);
> }
>
> sdkp->first_scan = 0;
> @@ -3227,6 +3263,12 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
>
> sd_revalidate_disk(gd);
>
> + if (sdkp->security) {
> + sdkp->opal_dev = init_opal_dev(sdp, &sd_sec_submit);
> + if (sdkp->opal_dev)
> + sd_printk(KERN_NOTICE, sdkp, "supports TCG Opal\n");
> + }
> +
>
I'm not familiar at all with ATA, but I noticed there was no unlock from suspend support
in the series. Does ATA not have a way to determine if we're coming out of a suspend?

I see there are some power-ops in scsi/sd.c, if you do want to add it you can mabe toss a

if (sdkp->security)
opal_unlock_from_suspend(sdpk->opal_dev)

somewhere in the resume path? We handle null opal_devs and no unlock from suspend list
so calling it when nothing is set up is just a no-op.