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>

2 files changed, 21 insertions, 7 deletions

diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
index f8bb746a549f..6bea6852bf27 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 b579f962451d..cad719876ef4 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;