[v8,09/12] nfit/libnvdimm: add support for issue secure erase DSM to Intel nvdimm

Commit Message

Dave Jiang Aug. 28, 2018, 10:48 p.m. UTC

Add support to issue a secure erase DSM to the Intel nvdimm. The
required passphrase is acquired from userspace through the kernel key
management. To trigger the action, "erase" is written to the "security"
sysfs attribute. libnvdimm will support the erase generic API call.

Signed-off-by: Dave Jiang <[e-mail]>
Reviewed-by: Dan Williams <[e-mail]>
---
 drivers/acpi/nfit/intel.c  |   58 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/nvdimm/dimm_devs.c |   49 +++++++++++++++++++++++++++++++++++++
 include/linux/libnvdimm.h  |    3 ++
 3 files changed, 110 insertions(+)

Patch

diff --git a/drivers/acpi/nfit/intel.c b/drivers/acpi/nfit/intel.c
index ba886f1f5399..419a7d54d4e8 100644
--- a/drivers/acpi/nfit/intel.c
+++ b/drivers/acpi/nfit/intel.c
@@ -18,6 +18,63 @@ 
 #include "intel.h"
 #include "nfit.h"
 
+static int intel_dimm_security_erase(struct nvdimm_bus *nvdimm_bus,
+		struct nvdimm *nvdimm, const struct nvdimm_key_data *nkey)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	int cmd_rc, rc = 0;
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+	struct {
+		struct nd_cmd_pkg pkg;
+		struct nd_intel_secure_erase cmd;
+	} nd_cmd = {
+		.pkg = {
+			.nd_command = NVDIMM_INTEL_SECURE_ERASE,
+			.nd_family = NVDIMM_FAMILY_INTEL,
+			.nd_size_in = ND_INTEL_PASSPHRASE_SIZE,
+			.nd_size_out = ND_INTEL_STATUS_SIZE,
+			.nd_fw_size = ND_INTEL_STATUS_SIZE,
+		},
+		.cmd = {
+			.status = 0,
+		},
+	};
+
+	if (!test_bit(NVDIMM_INTEL_SECURE_ERASE, &nfit_mem->dsm_mask))
+		return -ENOTTY;
+
+	/* flush all cache before we erase DIMM */
+	wbinvd_on_all_cpus();
+	memcpy(nd_cmd.cmd.passphrase, nkey->data,
+			sizeof(nd_cmd.cmd.passphrase));
+	rc = nd_desc->ndctl(nd_desc, nvdimm, ND_CMD_CALL, &nd_cmd,
+			sizeof(nd_cmd), &cmd_rc);
+	if (rc < 0)
+		goto out;
+	if (cmd_rc < 0) {
+		rc = cmd_rc;
+		goto out;
+	}
+
+	switch (nd_cmd.cmd.status) {
+	case 0:
+		break;
+	case ND_INTEL_STATUS_INVALID_PASS:
+		rc = -EINVAL;
+		goto out;
+	case ND_INTEL_STATUS_INVALID_STATE:
+	default:
+		rc = -ENXIO;
+		goto out;
+	}
+
+	/* DIMM erased, invalidate all CPU caches before we read it */
+	wbinvd_on_all_cpus();
+
+ out:
+	return rc;
+}
+
 static int intel_dimm_security_freeze_lock(struct nvdimm_bus *nvdimm_bus,
 		struct nvdimm *nvdimm)
 {
@@ -321,4 +378,5 @@  const struct nvdimm_security_ops intel_security_ops = {
 	.change_key = intel_dimm_security_update_passphrase,
 	.disable = intel_dimm_security_disable,
 	.freeze_lock = intel_dimm_security_freeze_lock,
+	.erase = intel_dimm_security_erase,
 };
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 338c3fedfdf3..102accb68893 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -143,6 +143,53 @@  int nvdimm_security_get_state(struct device *dev)
 			&nvdimm->state);
 }
 
+static int nvdimm_security_erase(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
+	struct key *key;
+	struct user_key_payload *payload;
+	int rc = 0;
+
+	if (!nvdimm->security_ops)
+		return 0;
+
+	/* lock the device and disallow driver bind */
+	device_lock(dev);
+	/* No driver data means dimm is disabled. Proceed if so. */
+	if (dev_get_drvdata(dev)) {
+		dev_warn(dev, "Unable to secure erase while DIMM active.\n");
+		rc = -EINVAL;
+		goto out;
+	}
+
+	if (nvdimm->state == NVDIMM_SECURITY_UNSUPPORTED)
+		goto out;
+
+	key = nvdimm_get_key(dev);
+	if (!key) {
+		dev_warn(dev, "no key found\n");
+		rc = -ENOKEY;
+		goto out;
+	}
+
+	down_read(&key->sem);
+	payload = key->payload.data[0];
+	rc = nvdimm->security_ops->erase(nvdimm_bus, nvdimm,
+			(void *)payload->data);
+	up_read(&key->sem);
+	/* remove key since secure erase kills the passphrase */
+	key_unlink(nvdimm_keyring, key);
+	key_invalidate(key);
+	nvdimm->key = NULL;
+	key_put(key);
+
+ out:
+	device_unlock(dev);
+	nvdimm_security_get_state(dev);
+	return rc;
+}
+
 static int nvdimm_security_freeze_lock(struct device *dev)
 {
 	struct nvdimm *nvdimm = to_nvdimm(dev);
@@ -819,6 +866,8 @@  static ssize_t security_store(struct device *dev,
 		rc = nvdimm_security_disable(dev);
 	else if (sysfs_streq(buf, "freeze"))
 		rc = nvdimm_security_freeze_lock(dev);
+	else if (sysfs_streq(buf, "erase"))
+		rc = nvdimm_security_erase(dev);
 	else
 		return -EINVAL;
 
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index bcab42caa948..0d85e092a6dd 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -187,6 +187,9 @@  struct nvdimm_security_ops {
 			const struct nvdimm_key_data *nkey);
 	int (*freeze_lock)(struct nvdimm_bus *nvdimm_bus,
 			struct nvdimm *nvdimm);
+	int (*erase)(struct nvdimm_bus *nvdimm_bus,
+			struct nvdimm *nvdimm,
+			const struct nvdimm_key_data *nkey);
 };
 
 void badrange_init(struct badrange *badrange);