linux/drivers/cxl/security.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
#include <linux/libnvdimm.h>
#include <asm/unaligned.h>
#include <linux/module.h>
#include <linux/async.h>
#include <linux/slab.h>
#include <linux/memregion.h>
#include "cxlmem.h"
#include "cxl.h"

static unsigned long cxl_pmem_get_security_flags(struct nvdimm *nvdimm,
						 enum nvdimm_passphrase_type ptype)
{
	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
	struct cxl_dev_state *cxlds = cxlmd->cxlds;
	unsigned long security_flags = 0;
	u32 sec_out;
	int rc;

	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_GET_SECURITY_STATE, NULL, 0,
			       &sec_out, sizeof(sec_out));
	if (rc < 0)
		return 0;

	if (ptype == NVDIMM_MASTER) {
		if (sec_out & CXL_PMEM_SEC_STATE_MASTER_PASS_SET)
			set_bit(NVDIMM_SECURITY_UNLOCKED, &security_flags);
		else
			set_bit(NVDIMM_SECURITY_DISABLED, &security_flags);
		if (sec_out & CXL_PMEM_SEC_STATE_MASTER_PLIMIT)
			set_bit(NVDIMM_SECURITY_FROZEN, &security_flags);
		return security_flags;
	}

	if (sec_out & CXL_PMEM_SEC_STATE_USER_PASS_SET) {
		if (sec_out & CXL_PMEM_SEC_STATE_FROZEN ||
		    sec_out & CXL_PMEM_SEC_STATE_USER_PLIMIT)
			set_bit(NVDIMM_SECURITY_FROZEN, &security_flags);

		if (sec_out & CXL_PMEM_SEC_STATE_LOCKED)
			set_bit(NVDIMM_SECURITY_LOCKED, &security_flags);
		else
			set_bit(NVDIMM_SECURITY_UNLOCKED, &security_flags);
	} else {
		set_bit(NVDIMM_SECURITY_DISABLED, &security_flags);
	}

	return security_flags;
}

static int cxl_pmem_security_change_key(struct nvdimm *nvdimm,
					const struct nvdimm_key_data *old_data,
					const struct nvdimm_key_data *new_data,
					enum nvdimm_passphrase_type ptype)
{
	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
	struct cxl_dev_state *cxlds = cxlmd->cxlds;
	struct cxl_set_pass set_pass;
	int rc;

	set_pass.type = ptype == NVDIMM_MASTER ?
		CXL_PMEM_SEC_PASS_MASTER : CXL_PMEM_SEC_PASS_USER;
	memcpy(set_pass.old_pass, old_data->data, NVDIMM_PASSPHRASE_LEN);
	memcpy(set_pass.new_pass, new_data->data, NVDIMM_PASSPHRASE_LEN);

	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_SET_PASSPHRASE,
			       &set_pass, sizeof(set_pass), NULL, 0);
	return rc;
}

static int cxl_pmem_security_disable(struct nvdimm *nvdimm,
				     const struct nvdimm_key_data *key_data)
{
	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
	struct cxl_dev_state *cxlds = cxlmd->cxlds;
	struct cxl_disable_pass dis_pass;
	int rc;

	dis_pass.type = CXL_PMEM_SEC_PASS_USER;
	memcpy(dis_pass.pass, key_data->data, NVDIMM_PASSPHRASE_LEN);

	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_DISABLE_PASSPHRASE,
			       &dis_pass, sizeof(dis_pass), NULL, 0);
	return rc;
}

static int cxl_pmem_security_freeze(struct nvdimm *nvdimm)
{
	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
	struct cxl_dev_state *cxlds = cxlmd->cxlds;

	return cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_FREEZE_SECURITY, NULL, 0, NULL, 0);
}

static int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
				    const struct nvdimm_key_data *key_data)
{
	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
	struct cxl_dev_state *cxlds = cxlmd->cxlds;
	u8 pass[NVDIMM_PASSPHRASE_LEN];
	int rc;

	if (!cpu_cache_has_invalidate_memregion())
		return -EINVAL;

	memcpy(pass, key_data->data, NVDIMM_PASSPHRASE_LEN);
	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_UNLOCK,
			       pass, NVDIMM_PASSPHRASE_LEN, NULL, 0);
	if (rc < 0)
		return rc;

	/* DIMM unlocked, invalidate all CPU caches before we read it */
	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
	return 0;
}

static const struct nvdimm_security_ops __cxl_security_ops = {
	.get_flags = cxl_pmem_get_security_flags,
	.change_key = cxl_pmem_security_change_key,
	.disable = cxl_pmem_security_disable,
	.freeze = cxl_pmem_security_freeze,
	.unlock = cxl_pmem_security_unlock,
};

const struct nvdimm_security_ops *cxl_security_ops = &__cxl_security_ops;

MODULE_IMPORT_NS(DEVMEM);