Re: [PATCH v4 13/18] nvdimm/cxl/pmem: Add support for master passphrase disable security command

[Ben Cheatham <benjamin.cheatham@amd.com>]

On 11/14/22 2:34 PM, Dave Jiang wrote:
> The original nvdimm_security_ops ->disable() only supports user passphrase
> for security disable. The CXL spec introduced the disabling of master
> passphrase. Add a ->disable_master() callback to support this new operation
> and leaving the old ->disable() mechanism alone. A "disable_master" command
> is added for the sysfs attribute in order to allow command to be issued
> from userspace. ndctl will need enabling in order to utilize this new
> operation.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>   drivers/cxl/security.c    |   20 ++++++++++++++++++--
>   drivers/nvdimm/security.c |   33 ++++++++++++++++++++++++++-------
>   include/linux/libnvdimm.h |    2 ++
>   3 files changed, 46 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/cxl/security.c b/drivers/cxl/security.c
> index 631a474939d6..f4df7d38e4cd 100644
> --- a/drivers/cxl/security.c
> +++ b/drivers/cxl/security.c
> @@ -71,8 +71,9 @@ static int cxl_pmem_security_change_key(struct nvdimm *nvdimm,
>   	return rc;
>   }
>   
> -static int cxl_pmem_security_disable(struct nvdimm *nvdimm,
> -				     const struct nvdimm_key_data *key_data)
> +static int __cxl_pmem_security_disable(struct nvdimm *nvdimm,
> +				       const struct nvdimm_key_data *key_data,
> +				       enum nvdimm_passphrase_type ptype)
>   {
>   	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
>   	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
> @@ -88,6 +89,8 @@ static int cxl_pmem_security_disable(struct nvdimm *nvdimm,
>   	 * will only support disable of user passphrase. The disable master passphrase
>   	 * ability will need to be added as a new callback.
>   	 */
> +	dis_pass.type = ptype == NVDIMM_MASTER ?
> +		CXL_PMEM_SEC_PASS_MASTER : CXL_PMEM_SEC_PASS_USER;
>   	dis_pass.type = CXL_PMEM_SEC_PASS_USER;

Hey Dave,

I noticed that you are overwriting dis_pass.type with 
CXL_PMEM_SEC_PASS_USER after your added change here. I imagine that's 
not intentional considering the rest of the work in this patch!

Ben
>   	memcpy(dis_pass.pass, key_data->data, NVDIMM_PASSPHRASE_LEN);
>   
> @@ -96,6 +99,18 @@ static int cxl_pmem_security_disable(struct nvdimm *nvdimm,
>   	return rc;
>   }
>   
> +static int cxl_pmem_security_disable(struct nvdimm *nvdimm,
> +				     const struct nvdimm_key_data *key_data)
> +{
> +	return __cxl_pmem_security_disable(nvdimm, key_data, NVDIMM_USER);
> +}
> +
> +static int cxl_pmem_security_disable_master(struct nvdimm *nvdimm,
> +					    const struct nvdimm_key_data *key_data)
> +{
> +	return __cxl_pmem_security_disable(nvdimm, key_data, NVDIMM_MASTER);
> +}
> +
>   static int cxl_pmem_security_freeze(struct nvdimm *nvdimm)
>   {
>   	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
> @@ -163,6 +178,7 @@ static const struct nvdimm_security_ops __cxl_security_ops = {
>   	.freeze = cxl_pmem_security_freeze,
>   	.unlock = cxl_pmem_security_unlock,
>   	.erase = cxl_pmem_security_passphrase_erase,
> +	.disable_master = cxl_pmem_security_disable_master,
>   };
>   
>   const struct nvdimm_security_ops *cxl_security_ops = &__cxl_security_ops;
> diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
> index 8aefb60c42ff..92af4c3ca0d3 100644
> --- a/drivers/nvdimm/security.c
> +++ b/drivers/nvdimm/security.c
> @@ -239,7 +239,8 @@ static int check_security_state(struct nvdimm *nvdimm)
>   	return 0;
>   }
>   
> -static int security_disable(struct nvdimm *nvdimm, unsigned int keyid)
> +static int security_disable(struct nvdimm *nvdimm, unsigned int keyid,
> +			    enum nvdimm_passphrase_type pass_type)
>   {
>   	struct device *dev = &nvdimm->dev;
>   	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
> @@ -250,8 +251,13 @@ static int security_disable(struct nvdimm *nvdimm, unsigned int keyid)
>   	/* The bus lock should be held at the top level of the call stack */
>   	lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
>   
> -	if (!nvdimm->sec.ops || !nvdimm->sec.ops->disable
> -			|| !nvdimm->sec.flags)
> +	if (!nvdimm->sec.ops || !nvdimm->sec.flags)
> +		return -EOPNOTSUPP;
> +
> +	if (pass_type == NVDIMM_USER && !nvdimm->sec.ops->disable)
> +		return -EOPNOTSUPP;
> +
> +	if (pass_type == NVDIMM_MASTER && !nvdimm->sec.ops->disable_master)
>   		return -EOPNOTSUPP;
>   
>   	rc = check_security_state(nvdimm);
> @@ -263,12 +269,21 @@ static int security_disable(struct nvdimm *nvdimm, unsigned int keyid)
>   	if (!data)
>   		return -ENOKEY;
>   
> -	rc = nvdimm->sec.ops->disable(nvdimm, data);
> -	dev_dbg(dev, "key: %d disable: %s\n", key_serial(key),
> +	if (pass_type == NVDIMM_MASTER) {
> +		rc = nvdimm->sec.ops->disable_master(nvdimm, data);
> +		dev_dbg(dev, "key: %d disable_master: %s\n", key_serial(key),
>   			rc == 0 ? "success" : "fail");
> +	} else {
> +		rc = nvdimm->sec.ops->disable(nvdimm, data);
> +		dev_dbg(dev, "key: %d disable: %s\n", key_serial(key),
> +			rc == 0 ? "success" : "fail");
> +	}
>   
>   	nvdimm_put_key(key);
> -	nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
> +	if (pass_type == NVDIMM_MASTER)
> +		nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
> +	else
> +		nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
>   	return rc;
>   }
>   
> @@ -473,6 +488,7 @@ void nvdimm_security_overwrite_query(struct work_struct *work)
>   #define OPS							\
>   	C( OP_FREEZE,		"freeze",		1),	\
>   	C( OP_DISABLE,		"disable",		2),	\
> +	C( OP_DISABLE_MASTER,	"disable_master",	2),	\
>   	C( OP_UPDATE,		"update",		3),	\
>   	C( OP_ERASE,		"erase",		2),	\
>   	C( OP_OVERWRITE,	"overwrite",		2),	\
> @@ -524,7 +540,10 @@ ssize_t nvdimm_security_store(struct device *dev, const char *buf, size_t len)
>   		rc = nvdimm_security_freeze(nvdimm);
>   	} else if (i == OP_DISABLE) {
>   		dev_dbg(dev, "disable %u\n", key);
> -		rc = security_disable(nvdimm, key);
> +		rc = security_disable(nvdimm, key, NVDIMM_USER);
> +	} else if (i == OP_DISABLE_MASTER) {
> +		dev_dbg(dev, "disable_master %u\n", key);
> +		rc = security_disable(nvdimm, key, NVDIMM_MASTER);
>   	} else if (i == OP_UPDATE || i == OP_MASTER_UPDATE) {
>   		dev_dbg(dev, "%s %u %u\n", ops[i].name, key, newkey);
>   		rc = security_update(nvdimm, key, newkey, i == OP_UPDATE
> diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
> index c74acfa1a3fe..3bf658a74ccb 100644
> --- a/include/linux/libnvdimm.h
> +++ b/include/linux/libnvdimm.h
> @@ -183,6 +183,8 @@ struct nvdimm_security_ops {
>   	int (*overwrite)(struct nvdimm *nvdimm,
>   			const struct nvdimm_key_data *key_data);
>   	int (*query_overwrite)(struct nvdimm *nvdimm);
> +	int (*disable_master)(struct nvdimm *nvdimm,
> +			      const struct nvdimm_key_data *key_data);
>   };
>   
>   enum nvdimm_fwa_state {
>
>