[PATCH 5.0 026/137] libnvdimm/security: provide fix for secure-erase to use zero-key

From: Greg Kroah-Hartman
Date: Wed May 15 2019 - 07:46:00 EST


[ Upstream commit 037c8489ade669e0f09ad40d5b91e5e1159a14b1 ]

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@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/nvdimm/security.c | 17 ++++++++++++-----
tools/testing/nvdimm/test/nfit.c | 11 +++++++++--
2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
index f8bb746a549f7..6bea6852bf278 100644
--- a/drivers/nvdimm/security.c
+++ b/drivers/nvdimm/security.c
@@ -22,6 +22,8 @@ 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);
@@ -286,8 +288,9 @@ 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;
+ 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);
@@ -319,11 +322,15 @@ int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyid,
return -EOPNOTSUPP;
}

- key = nvdimm_lookup_user_key(nvdimm, keyid, NVDIMM_BASE_KEY);
- if (!key)
- return -ENOKEY;
+ 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, key_data(key), pass_type);
+ 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");
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index b579f962451d6..cad719876ef45 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -225,6 +225,8 @@ static struct workqueue_struct *nfit_wq;

static struct gen_pool *nfit_pool;

+static const char zero_key[NVDIMM_PASSPHRASE_LEN];
+
static struct nfit_test *to_nfit_test(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
@@ -1059,8 +1061,7 @@ static int nd_intel_test_cmd_secure_erase(struct nfit_test *t,
struct device *dev = &t->pdev.dev;
struct nfit_test_sec *sec = &dimm_sec_info[dimm];

- if (!(sec->state & ND_INTEL_SEC_STATE_ENABLED) ||
- (sec->state & ND_INTEL_SEC_STATE_FROZEN)) {
+ if (sec->state & ND_INTEL_SEC_STATE_FROZEN) {
nd_cmd->status = ND_INTEL_STATUS_INVALID_STATE;
dev_dbg(dev, "secure erase: wrong security state\n");
} else if (memcmp(nd_cmd->passphrase, sec->passphrase,
@@ -1068,6 +1069,12 @@ static int nd_intel_test_cmd_secure_erase(struct nfit_test *t,
nd_cmd->status = ND_INTEL_STATUS_INVALID_PASS;
dev_dbg(dev, "secure erase: wrong passphrase\n");
} else {
+ if (!(sec->state & ND_INTEL_SEC_STATE_ENABLED)
+ && (memcmp(nd_cmd->passphrase, zero_key,
+ ND_INTEL_PASSPHRASE_SIZE) != 0)) {
+ dev_dbg(dev, "invalid zero key\n");
+ return 0;
+ }
memset(sec->passphrase, 0, ND_INTEL_PASSPHRASE_SIZE);
memset(sec->master_passphrase, 0, ND_INTEL_PASSPHRASE_SIZE);
sec->state = 0;
--
2.20.1