acpi/nfit, libnvdimm: Add support for issue secure erase DSM to Intel nvdimm

Add support to issue a secure erase DSM to the Intel nvdimm. The
required passphrase is acquired from an encrypted key in the kernel user
keyring. To trigger the action, "erase <keyid>" is written to the
"security" sysfs attribute.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

3 files changed, 53 insertions, 2 deletions

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 1cc3a6af3d0e..bc432b7c17b8 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -394,7 +394,8 @@ static ssize_t security_show(struct device *dev,
 #define OPS						\
 	C( OP_FREEZE,		"freeze",	1),	\
 	C( OP_DISABLE,		"disable",	2),	\
-	C( OP_UPDATE,		"update",	3)
+	C( OP_UPDATE,		"update",	3),	\
+	C( OP_ERASE,		"erase",	2)
 #undef C
 #define C(a, b, c) a
 enum nvdimmsec_op_ids { OPS };
@@ -448,6 +449,9 @@ static ssize_t __security_store(struct device *dev, const char *buf, size_t len)
 	} else if (i == OP_UPDATE) {
 		dev_dbg(dev, "update %u %u\n", key, newkey);
 		rc = nvdimm_security_update(nvdimm, key, newkey);
+	} else if (i == OP_ERASE) {
+		dev_dbg(dev, "erase %u\n", key);
+		rc = nvdimm_security_erase(nvdimm, key);
 	} else
 		return -EINVAL;
 
@@ -498,7 +502,8 @@ static umode_t nvdimm_visible(struct kobject *kobj, struct attribute *a, int n)
 		return 0;
 	/* Are there any state mutation ops? */
 	if (nvdimm->sec.ops->freeze || nvdimm->sec.ops->disable
-			|| nvdimm->sec.ops->change_key)
+			|| nvdimm->sec.ops->change_key
+			|| nvdimm->sec.ops->erase)
 		return a->mode;
 	return 0444;
 }
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index c2567f9ae07b..b4b633ccfbe9 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -61,6 +61,7 @@ int nvdimm_security_freeze(struct nvdimm *nvdimm);
 int nvdimm_security_disable(struct nvdimm *nvdimm, unsigned int keyid);
 int nvdimm_security_update(struct nvdimm *nvdimm, unsigned int keyid,
 		unsigned int new_keyid);
+int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyid);
 #else
 static inline int nvdimm_security_disable(struct nvdimm *nvdimm,
 		unsigned int keyid)
@@ -72,6 +73,10 @@ static inline int nvdimm_security_update(struct nvdimm *nvdimm, unsigned int key
 {
 	return -EOPNOTSUPP;
 }
+static inline int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyid)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 /**
diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
index df7f070e96fb..05677be3c0dd 100644
--- a/drivers/nvdimm/security.c
+++ b/drivers/nvdimm/security.c
@@ -33,6 +33,9 @@ static void *key_data(struct key *key)
 
 static void nvdimm_put_key(struct key *key)
 {
+	if (!key)
+		return;
+
 	up_read(&key->sem);
 	key_put(key);
 }
@@ -259,3 +262,41 @@ int nvdimm_security_update(struct nvdimm *nvdimm, unsigned int keyid,
 	nvdimm->sec.state = nvdimm_security_state(nvdimm);
 	return rc;
 }
+
+int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyid)
+{
+	struct device *dev = &nvdimm->dev;
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
+	struct key *key;
+	int rc;
+
+	/* 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->erase
+			|| nvdimm->sec.state < 0)
+		return -EOPNOTSUPP;
+
+	if (atomic_read(&nvdimm->busy)) {
+		dev_warn(dev, "Unable to secure erase while DIMM active.\n");
+		return -EBUSY;
+	}
+
+	if (nvdimm->sec.state >= NVDIMM_SECURITY_FROZEN) {
+		dev_warn(dev, "Incorrect security state: %d\n",
+				nvdimm->sec.state);
+		return -EIO;
+	}
+
+	key = nvdimm_lookup_user_key(nvdimm, keyid, NVDIMM_BASE_KEY);
+	if (!key)
+		return -ENOKEY;
+
+	rc = nvdimm->sec.ops->erase(nvdimm, key_data(key));
+	dev_dbg(dev, "key: %d erase: %s\n", key_serial(key),
+			rc == 0 ? "success" : "fail");
+
+	nvdimm_put_key(key);
+	nvdimm->sec.state = nvdimm_security_state(nvdimm);
+	return rc;
+}