Re: [PATCH v4 11/16] block: sed-opal: ioctl for writing to shadow mbr

From: Derrick, Jonathan
Date: Fri Feb 08 2019 - 17:58:29 EST

On Fri, 2019-02-01 at 21:50 +0100, David Kozub wrote:
> From: Jonas Rabenstein <jonas.rabenstein@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Allow modification of the shadow mbr. If the shadow mbr is not marked as
> done, this data will be presented read only as the device content. Only
> after marking the shadow mbr as done and unlocking a locking range the
> actual content is accessible.
>
> Co-authored-by: David Kozub <zub@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Jonas Rabenstein <jonas.rabenstein@xxxxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: David Kozub <zub@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Scott Bauer <sbauer@xxxxxxxxxxxxxx>
> ---
> block/sed-opal.c | 89 ++++++++++++++++++++++++++++++++++-
> include/linux/sed-opal.h | 1 +
> include/uapi/linux/sed-opal.h | 8 ++++
> 3 files changed, 97 insertions(+), 1 deletion(-)
>
> diff --git a/block/sed-opal.c b/block/sed-opal.c
> index e03838cfd31b..88c84906ce98 100644
> --- a/block/sed-opal.c
> +++ b/block/sed-opal.c
> @@ -34,6 +34,9 @@
> #define IO_BUFFER_LENGTH 2048
> #define MAX_TOKS 64
>
> +/* Number of bytes needed by cmd_finalize. */
> +#define CMD_FINALIZE_BYTES_NEEDED 7
> +
> struct opal_step {
> int (*fn)(struct opal_dev *dev, void *data);
> void *data;
> @@ -668,7 +671,11 @@ static int cmd_finalize(struct opal_dev *cmd, u32 hsn, u32 tsn)
> struct opal_header *hdr;
> int err = 0;
>
> - /* close the parameter list opened from cmd_start */
> + /*
> + * Close the parameter list opened from cmd_start.
> + * The number of bytes added must be equal to
> + * CMD_FINALIZE_BYTES_NEEDED.
> + */
> add_token_u8(&err, cmd, OPAL_ENDLIST);
>
> add_token_u8(&err, cmd, OPAL_ENDOFDATA);
> @@ -1500,6 +1507,58 @@ static int set_mbr_enable_disable(struct opal_dev *dev, void *data)
> return finalize_and_send(dev, parse_and_check_status);
> }
>
> +static int write_shadow_mbr(struct opal_dev *dev, void *data)
> +{
> + struct opal_shadow_mbr *shadow = data;
> + const u8 __user *src;
> + u8 *dst;
> + size_t off = 0;
> + u64 len;
> + int err = 0;
> +
> + /* do the actual transmission(s) */
> + src = (u8 *) shadow->data;
> + while (off < shadow->size) {
> + err = cmd_start(dev, opaluid[OPAL_MBR], opalmethod[OPAL_SET]);
> + add_token_u8(&err, dev, OPAL_STARTNAME);
> + add_token_u8(&err, dev, OPAL_WHERE);
> + add_token_u64(&err, dev, shadow->offset + off);
> + add_token_u8(&err, dev, OPAL_ENDNAME);
> +
> + add_token_u8(&err, dev, OPAL_STARTNAME);
> + add_token_u8(&err, dev, OPAL_VALUES);
> +
> + /*
> + * The bytestring header is either 1 or 2 bytes, so assume 2.
> + * There also needs to be enough space to accommodate the
> + * trailing OPAL_ENDNAME (1 byte) and tokens added by
> + * cmd_finalize.
> + */
> + len = min(remaining_size(dev) - (2+1+CMD_FINALIZE_BYTES_NEEDED),
> + (size_t)(shadow->size - off));
> + pr_debug("MBR: write bytes %zu+%llu/%llu\n",
> + off, len, shadow->size);
> +
> + dst = add_bytestring_header(&err, dev, len);
> + if (!dst)
> + break;
> + if (copy_from_user(dst, src + off, len))
> + err = -EFAULT;
> + dev->pos += len;
> +
> + add_token_u8(&err, dev, OPAL_ENDNAME);
> + if (err)
> + break;
> +
> + err = finalize_and_send(dev, parse_and_check_status);
> + if (err)
> + break;
> +
> + off += len;
> + }
> + return err;
> +}
> +
> static int generic_pw_cmd(u8 *key, size_t key_len, u8 *cpin_uid,
> struct opal_dev *dev)
> {
> @@ -2045,6 +2104,31 @@ static int opal_mbr_status(struct opal_dev *dev, struct opal_mbr_data *opal_mbr)
> return ret;
> }
>
> +static int opal_write_shadow_mbr(struct opal_dev *dev,
> + struct opal_shadow_mbr *info)
> +{
> + const struct opal_step mbr_steps[] = {
> + { opal_discovery0, },
> + { start_admin1LSP_opal_session, &info->key },
> + { write_shadow_mbr, info },
> + { end_opal_session, },
> + { NULL, }
> + };
> + int ret;
> +
> + if (info->size == 0)
> + return 0;
> +
> + if (!access_ok(info->data, info->size))
> + return -EINVAL;
-EFAULT?

> +
> + mutex_lock(&dev->dev_lock);
> + setup_opal_dev(dev, mbr_steps);
> + ret = next(dev);
> + mutex_unlock(&dev->dev_lock);
> + return ret;
> +}
> +
> static int opal_save(struct opal_dev *dev, struct opal_lock_unlock *lk_unlk)
> {
> struct opal_suspend_data *suspend;
> @@ -2378,6 +2462,9 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
> case IOC_OPAL_MBR_STATUS:
> ret = opal_mbr_status(dev, p);
> break;
> + case IOC_OPAL_WRITE_SHADOW_MBR:
> + ret = opal_write_shadow_mbr(dev, p);
> + break;
> case IOC_OPAL_ERASE_LR:
> ret = opal_erase_locking_range(dev, p);
> break;
> diff --git a/include/linux/sed-opal.h b/include/linux/sed-opal.h
> index b38dc602cae3..cf08cdc13cbd 100644
> --- a/include/linux/sed-opal.h
> +++ b/include/linux/sed-opal.h
> @@ -47,6 +47,7 @@ static inline bool is_sed_ioctl(unsigned int cmd)
> case IOC_OPAL_ENABLE_DISABLE_MBR:
> case IOC_OPAL_ERASE_LR:
> case IOC_OPAL_SECURE_ERASE_LR:
> + case IOC_OPAL_WRITE_SHADOW_MBR:
> case IOC_OPAL_MBR_STATUS:
> return true;
> }
> diff --git a/include/uapi/linux/sed-opal.h b/include/uapi/linux/sed-opal.h
> index 0cb9890cdc04..8e84307f66d4 100644
> --- a/include/uapi/linux/sed-opal.h
> +++ b/include/uapi/linux/sed-opal.h
> @@ -104,6 +104,13 @@ struct opal_mbr_data {
> __u8 __align[7];
> };
>
> +struct opal_shadow_mbr {
> + struct opal_key key;
> + const __u64 data;
> + __u64 offset;
> + __u64 size;
> +};
> +
> #define IOC_OPAL_SAVE _IOW('p', 220, struct opal_lock_unlock)
> #define IOC_OPAL_LOCK_UNLOCK _IOW('p', 221, struct opal_lock_unlock)
> #define IOC_OPAL_TAKE_OWNERSHIP _IOW('p', 222, struct opal_key)
> @@ -117,5 +124,6 @@ struct opal_mbr_data {
> #define IOC_OPAL_ERASE_LR _IOW('p', 230, struct opal_session_info)
> #define IOC_OPAL_SECURE_ERASE_LR _IOW('p', 231, struct opal_session_info)
> #define IOC_OPAL_MBR_STATUS _IOW('p', 232, struct opal_mbr_data)
> +#define IOC_OPAL_WRITE_SHADOW_MBR _IOW('p', 233, struct opal_shadow_mbr)
>
> #endif /* _UAPI_SED_OPAL_H */
Otherwise looks good

Reviewed-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>

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