AuxXxilium/linux_dsm_epyc7002
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linux_dsm_epyc7002/drivers/nvdimm/security.c
Dave Jiang 7d988097c5 acpi/nfit, libnvdimm/security: Add security DSM overwrite support 
Add support for the NVDIMM_FAMILY_INTEL "ovewrite" capability as
described by the Intel DSM spec v1.7. This will allow triggering of
overwrite on Intel NVDIMMs. The overwrite operation can take tens of
minutes. When the overwrite DSM is issued successfully, the NVDIMMs will
be unaccessible. The kernel will do backoff polling to detect when the
overwrite process is completed. According to the DSM spec v1.7, the 128G
NVDIMMs can take up to 15mins to perform overwrite and larger DIMMs will
take longer.

Given that overwrite puts the DIMM in an indeterminate state until it
completes introduce the NDD_SECURITY_OVERWRITE flag to prevent other
operations from executing when overwrite is happening. The
NDD_WORK_PENDING flag is added to denote that there is a device reference
on the nvdimm device for an async workqueue thread context.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-12-21 12:44:41 -08:00

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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 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_warn(dev, "request_key() found no key\n");
else
dev_warn(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));
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_warn(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);
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_warn(dev, "Incorrect security state: %d\n",
nvdimm->sec.state);
return -EIO;
}
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_warn(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);
return rc;
}
int nvdimm_security_update(struct nvdimm *nvdimm, unsigned int keyid,
unsigned int new_keyid)
{
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_warn(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));
dev_dbg(dev, "key: %d %d update: %s\n",
key_serial(key), key_serial(newkey),
rc == 0 ? "success" : "fail");
nvdimm_put_key(newkey);
nvdimm_put_key(key);
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;
}
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_warn(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->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;
}
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_warn(dev, "Unable to overwrite while DIMM active.\n");
return -EBUSY;
}
if (dev->driver == NULL) {
dev_warn(dev, "Unable to overwrite while DIMM active.\n");
return -EINVAL;
}
if (nvdimm->sec.state >= NVDIMM_SECURITY_FROZEN) {
dev_warn(dev, "Incorrect security state: %d\n",
nvdimm->sec.state);
return -EIO;
}
if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
dev_warn(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_warn(&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);
}
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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