Re: [PATCH v4 08/15] ufs: core: add support to derive software secret

[Om Prakash Singh <quic_omprsing@quicinc.com>]

On 1/28/2024 4:44 AM, Gaurav Kashyap wrote:
> Block crypto allows storage controllers like UFS to
> register an op derive a software secret from wrapped
> keys added to the kernel.
> 
> Wrapped keys in most cases will have vendor specific
> implementations, which means this op would need to have
> a corresponding UFS variant op.
> This change adds hooks in UFS core to support this variant
> ops and tie them to the blk crypto op.
> 
> Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com>
> Tested-by: Neil Armstrong <neil.armstrong@linaro.org>
> ---
Reviewed-by: Om Prakash Singh <quic_omprsing@quicinc.com>

>   drivers/ufs/core/ufshcd-crypto.c | 15 +++++++++++++++
>   include/ufs/ufshcd.h             |  4 ++++
>   2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/ufs/core/ufshcd-crypto.c b/drivers/ufs/core/ufshcd-crypto.c
> index 399b55d67b3b..c14800eac1ff 100644
> --- a/drivers/ufs/core/ufshcd-crypto.c
> +++ b/drivers/ufs/core/ufshcd-crypto.c
> @@ -119,6 +119,20 @@ static int ufshcd_crypto_keyslot_evict(struct blk_crypto_profile *profile,
>   	return ufshcd_clear_keyslot(hba, slot);
>   }
>   
> +static int ufshcd_crypto_derive_sw_secret(struct blk_crypto_profile *profile,
> +					  const u8 wkey[], size_t wkey_size,
> +					  u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE])
> +{
> +	struct ufs_hba *hba =
> +		container_of(profile, struct ufs_hba, crypto_profile);
> +
> +	if (hba->vops && hba->vops->derive_sw_secret)
> +		return  hba->vops->derive_sw_secret(hba, wkey, wkey_size,
> +						    sw_secret);
> +
> +	return -EOPNOTSUPP;
> +}
> +
>   bool ufshcd_crypto_enable(struct ufs_hba *hba)
>   {
>   	if (!(hba->caps & UFSHCD_CAP_CRYPTO))
> @@ -132,6 +146,7 @@ bool ufshcd_crypto_enable(struct ufs_hba *hba)
>   static const struct blk_crypto_ll_ops ufshcd_crypto_ops = {
>   	.keyslot_program	= ufshcd_crypto_keyslot_program,
>   	.keyslot_evict		= ufshcd_crypto_keyslot_evict,
> +	.derive_sw_secret	= ufshcd_crypto_derive_sw_secret,
>   };
>   
>   static enum blk_crypto_mode_num
> diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
> index 680c010a53d4..8a773434a329 100644
> --- a/include/ufs/ufshcd.h
> +++ b/include/ufs/ufshcd.h
> @@ -321,6 +321,7 @@ struct ufs_pwr_mode_info {
>    * @device_reset: called to issue a reset pulse on the UFS device
>    * @config_scaling_param: called to configure clock scaling parameters
>    * @program_key: program or evict an inline encryption key
> + * @derive_sw_secret: derive sw secret from a wrapped key
>    * @event_notify: called to notify important events
>    * @reinit_notify: called to notify reinit of UFSHCD during max gear switch
>    * @mcq_config_resource: called to configure MCQ platform resources
> @@ -365,6 +366,9 @@ struct ufs_hba_variant_ops {
>   	int	(*program_key)(struct ufs_hba *hba,
>   			       const struct blk_crypto_key *bkey,
>   			       const union ufs_crypto_cfg_entry *cfg, int slot);
> +	int	(*derive_sw_secret)(struct ufs_hba *hba, const u8 wkey[],
> +				    unsigned int wkey_size,
> +				    u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]);
>   	void	(*event_notify)(struct ufs_hba *hba,
>   				enum ufs_event_type evt, void *data);
>   	void	(*reinit_notify)(struct ufs_hba *);