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037c8489ad
linux-next/drivers/nvdimm/security.c
Dave Jiang 037c8489ad libnvdimm/security: provide fix for secure-erase to use zero-key 
Add a zero key in order to standardize hardware that want a key of 0's to
be passed. Some platforms defaults to a zero-key with security enabled
rather than allow the OS to enable the security. The zero key would allow
us to manage those platform as well. This also adds a fix to secure erase
so it can use the zero key to do crypto erase. Some other security commands
already use zero keys. This introduces a standard zero-key to allow
unification of semantics cross nvdimm security commands.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-03-30 08:26:37 -07:00

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// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2018 Intel Corporation. All rights reserved. */
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ndctl.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/cred.h>
#include <linux/key.h>
#include <linux/key-type.h>
#include <keys/user-type.h>
#include <keys/encrypted-type.h>
#include "nd-core.h"
#include "nd.h"
#define NVDIMM_BASE_KEY 0
#define NVDIMM_NEW_KEY 1
static bool key_revalidate = true;
module_param(key_revalidate, bool, 0444);
MODULE_PARM_DESC(key_revalidate, "Require key validation at init.");
static const char zero_key[NVDIMM_PASSPHRASE_LEN];
static void *key_data(struct key *key)
{
struct encrypted_key_payload *epayload = dereference_key_locked(key);
lockdep_assert_held_read(&key->sem);
return epayload->decrypted_data;
}
static void nvdimm_put_key(struct key *key)
{
if (!key)
return;
up_read(&key->sem);
key_put(key);
}
/*
* Retrieve kernel key for DIMM and request from user space if
* necessary. Returns a key held for read and must be put by
* nvdimm_put_key() before the usage goes out of scope.
*/
static struct key *nvdimm_request_key(struct nvdimm *nvdimm)
{
struct key *key = NULL;
static const char NVDIMM_PREFIX[] = "nvdimm:";
char desc[NVDIMM_KEY_DESC_LEN + sizeof(NVDIMM_PREFIX)];
struct device *dev = &nvdimm->dev;
sprintf(desc, "%s%s", NVDIMM_PREFIX, nvdimm->dimm_id);
key = request_key(&key_type_encrypted, desc, "");
if (IS_ERR(key)) {
if (PTR_ERR(key) == -ENOKEY)
dev_dbg(dev, "request_key() found no key\n");
else
dev_dbg(dev, "request_key() upcall failed\n");
key = NULL;
} else {
struct encrypted_key_payload *epayload;
down_read(&key->sem);
epayload = dereference_key_locked(key);
if (epayload->decrypted_datalen != NVDIMM_PASSPHRASE_LEN) {
up_read(&key->sem);
key_put(key);
key = NULL;
}
}
return key;
}
static struct key *nvdimm_lookup_user_key(struct nvdimm *nvdimm,
key_serial_t id, int subclass)
{
key_ref_t keyref;
struct key *key;
struct encrypted_key_payload *epayload;
struct device *dev = &nvdimm->dev;
keyref = lookup_user_key(id, 0, 0);
if (IS_ERR(keyref))
return NULL;
key = key_ref_to_ptr(keyref);
if (key->type != &key_type_encrypted) {
key_put(key);
return NULL;
}
dev_dbg(dev, "%s: key found: %#x\n", __func__, key_serial(key));
down_read_nested(&key->sem, subclass);
epayload = dereference_key_locked(key);
if (epayload->decrypted_datalen != NVDIMM_PASSPHRASE_LEN) {
up_read(&key->sem);
key_put(key);
key = NULL;
}
return key;
}
static struct key *nvdimm_key_revalidate(struct nvdimm *nvdimm)
{
struct key *key;
int rc;
if (!nvdimm->sec.ops->change_key)
return NULL;
key = nvdimm_request_key(nvdimm);
if (!key)
return NULL;
/*
* Send the same key to the hardware as new and old key to
* verify that the key is good.
*/
rc = nvdimm->sec.ops->change_key(nvdimm, key_data(key),
key_data(key), NVDIMM_USER);
if (rc < 0) {
nvdimm_put_key(key);
key = NULL;
}
return key;
}
static int __nvdimm_security_unlock(struct nvdimm *nvdimm)
{
struct device *dev = &nvdimm->dev;
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
struct key *key = NULL;
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->unlock
|| nvdimm->sec.state < 0)
return -EIO;
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_dbg(dev, "Security operation in progress.\n");
return -EBUSY;
}
/*
* If the pre-OS has unlocked the DIMM, attempt to send the key
* from request_key() to the hardware for verification. Failure
* to revalidate the key against the hardware results in a
* freeze of the security configuration. I.e. if the OS does not
* have the key, security is being managed pre-OS.
*/
if (nvdimm->sec.state == NVDIMM_SECURITY_UNLOCKED) {
if (!key_revalidate)
return 0;
key = nvdimm_key_revalidate(nvdimm);
if (!key)
return nvdimm_security_freeze(nvdimm);
} else
key = nvdimm_request_key(nvdimm);
if (!key)
return -ENOKEY;
rc = nvdimm->sec.ops->unlock(nvdimm, key_data(key));
dev_dbg(dev, "key: %d unlock: %s\n", key_serial(key),
rc == 0 ? "success" : "fail");
nvdimm_put_key(key);
nvdimm->sec.state = nvdimm_security_state(nvdimm, NVDIMM_USER);
return rc;
}
int nvdimm_security_unlock(struct device *dev)
{
struct nvdimm *nvdimm = to_nvdimm(dev);
int rc;
nvdimm_bus_lock(dev);
rc = __nvdimm_security_unlock(nvdimm);
nvdimm_bus_unlock(dev);
return rc;
}
int nvdimm_security_disable(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->disable
|| nvdimm->sec.state < 0)
return -EOPNOTSUPP;
if (nvdimm->sec.state >= NVDIMM_SECURITY_FROZEN) {
dev_dbg(dev, "Incorrect security state: %d\n",
nvdimm->sec.state);
return -EIO;
}
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_dbg(dev, "Security operation in progress.\n");
return -EBUSY;
}
key = nvdimm_lookup_user_key(nvdimm, keyid, NVDIMM_BASE_KEY);
if (!key)
return -ENOKEY;
rc = nvdimm->sec.ops->disable(nvdimm, key_data(key));
dev_dbg(dev, "key: %d disable: %s\n", key_serial(key),
rc == 0 ? "success" : "fail");
nvdimm_put_key(key);
nvdimm->sec.state = nvdimm_security_state(nvdimm, NVDIMM_USER);
return rc;
}
int nvdimm_security_update(struct nvdimm *nvdimm, unsigned int keyid,
unsigned int new_keyid,
enum nvdimm_passphrase_type pass_type)
{
struct device *dev = &nvdimm->dev;
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
struct key *key, *newkey;
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->change_key
|| nvdimm->sec.state < 0)
return -EOPNOTSUPP;
if (nvdimm->sec.state >= NVDIMM_SECURITY_FROZEN) {
dev_dbg(dev, "Incorrect security state: %d\n",
nvdimm->sec.state);
return -EIO;
}
if (keyid == 0)
key = NULL;
else {
key = nvdimm_lookup_user_key(nvdimm, keyid, NVDIMM_BASE_KEY);
if (!key)
return -ENOKEY;
}
newkey = nvdimm_lookup_user_key(nvdimm, new_keyid, NVDIMM_NEW_KEY);
if (!newkey) {
nvdimm_put_key(key);
return -ENOKEY;
}
rc = nvdimm->sec.ops->change_key(nvdimm, key ? key_data(key) : NULL,
key_data(newkey), pass_type);
dev_dbg(dev, "key: %d %d update%s: %s\n",
key_serial(key), key_serial(newkey),
pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
rc == 0 ? "success" : "fail");
nvdimm_put_key(newkey);
nvdimm_put_key(key);
if (pass_type == NVDIMM_MASTER)
nvdimm->sec.ext_state = nvdimm_security_state(nvdimm,
NVDIMM_MASTER);
else
nvdimm->sec.state = nvdimm_security_state(nvdimm,
NVDIMM_USER);
return rc;
}
int nvdimm_security_erase(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);
struct key *key = NULL;
int rc;
const void *data;
/* 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_dbg(dev, "Unable to secure erase while DIMM active.\n");
return -EBUSY;
}
if (nvdimm->sec.state >= NVDIMM_SECURITY_FROZEN) {
dev_dbg(dev, "Incorrect security state: %d\n",
nvdimm->sec.state);
return -EIO;
}
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_dbg(dev, "Security operation in progress.\n");
return -EBUSY;
}
if (nvdimm->sec.ext_state != NVDIMM_SECURITY_UNLOCKED
&& pass_type == NVDIMM_MASTER) {
dev_dbg(dev,
"Attempt to secure erase in wrong master state.\n");
return -EOPNOTSUPP;
}
if (keyid != 0) {
key = nvdimm_lookup_user_key(nvdimm, keyid, NVDIMM_BASE_KEY);
if (!key)
return -ENOKEY;
data = key_data(key);
} else
data = zero_key;
rc = nvdimm->sec.ops->erase(nvdimm, data, pass_type);
dev_dbg(dev, "key: %d erase%s: %s\n", key_serial(key),
pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
rc == 0 ? "success" : "fail");
nvdimm_put_key(key);
nvdimm->sec.state = nvdimm_security_state(nvdimm, NVDIMM_USER);
return rc;
}
int nvdimm_security_overwrite(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->overwrite
|| nvdimm->sec.state < 0)
return -EOPNOTSUPP;
if (atomic_read(&nvdimm->busy)) {
dev_dbg(dev, "Unable to overwrite while DIMM active.\n");
return -EBUSY;
}
if (dev->driver == NULL) {
dev_dbg(dev, "Unable to overwrite while DIMM active.\n");
return -EINVAL;
}
if (nvdimm->sec.state >= NVDIMM_SECURITY_FROZEN) {
dev_dbg(dev, "Incorrect security state: %d\n",
nvdimm->sec.state);
return -EIO;
}
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_dbg(dev, "Security operation in progress.\n");
return -EBUSY;
}
if (keyid == 0)
key = NULL;
else {
key = nvdimm_lookup_user_key(nvdimm, keyid, NVDIMM_BASE_KEY);
if (!key)
return -ENOKEY;
}
rc = nvdimm->sec.ops->overwrite(nvdimm, key ? key_data(key) : NULL);
dev_dbg(dev, "key: %d overwrite submission: %s\n", key_serial(key),
rc == 0 ? "success" : "fail");
nvdimm_put_key(key);
if (rc == 0) {
set_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
set_bit(NDD_WORK_PENDING, &nvdimm->flags);
nvdimm->sec.state = NVDIMM_SECURITY_OVERWRITE;
/*
* Make sure we don't lose device while doing overwrite
* query.
*/
get_device(dev);
queue_delayed_work(system_wq, &nvdimm->dwork, 0);
}
return rc;
}
void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
{
struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nvdimm->dev);
int rc;
unsigned int tmo;
/* The bus lock should be held at the top level of the call stack */
lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
/*
* Abort and release device if we no longer have the overwrite
* flag set. It means the work has been canceled.
*/
if (!test_bit(NDD_WORK_PENDING, &nvdimm->flags))
return;
tmo = nvdimm->sec.overwrite_tmo;
if (!nvdimm->sec.ops || !nvdimm->sec.ops->query_overwrite
|| nvdimm->sec.state < 0)
return;
rc = nvdimm->sec.ops->query_overwrite(nvdimm);
if (rc == -EBUSY) {
/* setup delayed work again */
tmo += 10;
queue_delayed_work(system_wq, &nvdimm->dwork, tmo * HZ);
nvdimm->sec.overwrite_tmo = min(15U * 60U, tmo);
return;
}
if (rc < 0)
dev_dbg(&nvdimm->dev, "overwrite failed\n");
else
dev_dbg(&nvdimm->dev, "overwrite completed\n");
if (nvdimm->sec.overwrite_state)
sysfs_notify_dirent(nvdimm->sec.overwrite_state);
nvdimm->sec.overwrite_tmo = 0;
clear_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
put_device(&nvdimm->dev);
nvdimm->sec.state = nvdimm_security_state(nvdimm, NVDIMM_USER);
nvdimm->sec.ext_state = nvdimm_security_state(nvdimm, NVDIMM_MASTER);
}
void nvdimm_security_overwrite_query(struct work_struct *work)
{
struct nvdimm *nvdimm =
container_of(work, typeof(*nvdimm), dwork.work);
nvdimm_bus_lock(&nvdimm->dev);
__nvdimm_security_overwrite_query(nvdimm);
nvdimm_bus_unlock(&nvdimm->dev);
}
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