]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
acpi/nfit, libnvdimm: Add unlock of nvdimm support for Intel DIMMs
authorDave Jiang <dave.jiang@intel.com>
Thu, 6 Dec 2018 20:40:01 +0000 (12:40 -0800)
committerDan Williams <dan.j.williams@intel.com>
Fri, 14 Dec 2018 01:54:13 +0000 (17:54 -0800)
Add support to unlock the dimm via the kernel key management APIs. The
passphrase is expected to be pulled from userspace through keyutils.
The key management and sysfs attributes are libnvdimm generic.

Encrypted keys are used to protect the nvdimm passphrase at rest. The
master key can be a trusted-key sealed in a TPM, preferred, or an
encrypted-key, more flexible, but more exposure to a potential attacker.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/acpi/nfit/intel.c
drivers/nvdimm/Kconfig
drivers/nvdimm/Makefile
drivers/nvdimm/dimm.c
drivers/nvdimm/nd.h
drivers/nvdimm/security.c [new file with mode: 0644]
include/linux/libnvdimm.h
tools/testing/nvdimm/Kbuild

index f98d680d1a399f30c50ae271dc7487cf4bbc3334..38f2cb364853d40a3e6be998ff511250eba381e0 100644 (file)
@@ -3,6 +3,7 @@
 #include <linux/libnvdimm.h>
 #include <linux/ndctl.h>
 #include <linux/acpi.h>
+#include <asm/smp.h>
 #include "intel.h"
 #include "nfit.h"
 
@@ -75,8 +76,116 @@ static int intel_security_freeze(struct nvdimm *nvdimm)
        return 0;
 }
 
+static int intel_security_change_key(struct nvdimm *nvdimm,
+               const struct nvdimm_key_data *old_data,
+               const struct nvdimm_key_data *new_data)
+{
+       struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+       struct {
+               struct nd_cmd_pkg pkg;
+               struct nd_intel_set_passphrase cmd;
+       } nd_cmd = {
+               .pkg = {
+                       .nd_command = NVDIMM_INTEL_SET_PASSPHRASE,
+                       .nd_family = NVDIMM_FAMILY_INTEL,
+                       .nd_size_in = ND_INTEL_PASSPHRASE_SIZE * 2,
+                       .nd_size_out = ND_INTEL_STATUS_SIZE,
+                       .nd_fw_size = ND_INTEL_STATUS_SIZE,
+               },
+       };
+       int rc;
+
+       if (!test_bit(NVDIMM_INTEL_SET_PASSPHRASE, &nfit_mem->dsm_mask))
+               return -ENOTTY;
+
+       if (old_data)
+               memcpy(nd_cmd.cmd.old_pass, old_data->data,
+                               sizeof(nd_cmd.cmd.old_pass));
+       memcpy(nd_cmd.cmd.new_pass, new_data->data,
+                       sizeof(nd_cmd.cmd.new_pass));
+       rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
+       if (rc < 0)
+               return rc;
+
+       switch (nd_cmd.cmd.status) {
+       case 0:
+               return 0;
+       case ND_INTEL_STATUS_INVALID_PASS:
+               return -EINVAL;
+       case ND_INTEL_STATUS_NOT_SUPPORTED:
+               return -EOPNOTSUPP;
+       case ND_INTEL_STATUS_INVALID_STATE:
+       default:
+               return -EIO;
+       }
+}
+
+static void nvdimm_invalidate_cache(void);
+
+static int intel_security_unlock(struct nvdimm *nvdimm,
+               const struct nvdimm_key_data *key_data)
+{
+       struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+       struct {
+               struct nd_cmd_pkg pkg;
+               struct nd_intel_unlock_unit cmd;
+       } nd_cmd = {
+               .pkg = {
+                       .nd_command = NVDIMM_INTEL_UNLOCK_UNIT,
+                       .nd_family = NVDIMM_FAMILY_INTEL,
+                       .nd_size_in = ND_INTEL_PASSPHRASE_SIZE,
+                       .nd_size_out = ND_INTEL_STATUS_SIZE,
+                       .nd_fw_size = ND_INTEL_STATUS_SIZE,
+               },
+       };
+       int rc;
+
+       if (!test_bit(NVDIMM_INTEL_UNLOCK_UNIT, &nfit_mem->dsm_mask))
+               return -ENOTTY;
+
+       memcpy(nd_cmd.cmd.passphrase, key_data->data,
+                       sizeof(nd_cmd.cmd.passphrase));
+       rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
+       if (rc < 0)
+               return rc;
+       switch (nd_cmd.cmd.status) {
+       case 0:
+               break;
+       case ND_INTEL_STATUS_INVALID_PASS:
+               return -EINVAL;
+       default:
+               return -EIO;
+       }
+
+       /* DIMM unlocked, invalidate all CPU caches before we read it */
+       nvdimm_invalidate_cache();
+
+       return 0;
+}
+
+/*
+ * TODO: define a cross arch wbinvd equivalent when/if
+ * NVDIMM_FAMILY_INTEL command support arrives on another arch.
+ */
+#ifdef CONFIG_X86
+static void nvdimm_invalidate_cache(void)
+{
+       wbinvd_on_all_cpus();
+}
+#else
+static void nvdimm_invalidate_cache(void)
+{
+       WARN_ON_ONCE("cache invalidation required after unlock\n");
+}
+#endif
+
 static const struct nvdimm_security_ops __intel_security_ops = {
        .state = intel_security_state,
        .freeze = intel_security_freeze,
+       .change_key = intel_security_change_key,
+#ifdef CONFIG_X86
+       .unlock = intel_security_unlock,
+#endif
 };
+
 const struct nvdimm_security_ops *intel_security_ops = &__intel_security_ops;
index 9d36473dc2a24f2100d4e748cb5540ce14931c0c..5e27918e4624a87ae40afb20235de64e16f81b6b 100644 (file)
@@ -112,4 +112,9 @@ config OF_PMEM
 
          Select Y if unsure.
 
+config NVDIMM_KEYS
+       def_bool y
+       depends on ENCRYPTED_KEYS
+       depends on (LIBNVDIMM=ENCRYPTED_KEYS) || LIBNVDIMM=m
+
 endif
index e8847045dac006e7fe884f6306bbc40c16a5512b..6f2a088afad6887db9eda81bfbfb26316f365a0f 100644 (file)
@@ -27,3 +27,4 @@ libnvdimm-$(CONFIG_ND_CLAIM) += claim.o
 libnvdimm-$(CONFIG_BTT) += btt_devs.o
 libnvdimm-$(CONFIG_NVDIMM_PFN) += pfn_devs.o
 libnvdimm-$(CONFIG_NVDIMM_DAX) += dax_devs.o
+libnvdimm-$(CONFIG_NVDIMM_KEYS) += security.o
index 9899c97138a396b4d87bcc8d906c2f47be214634..1b3d9e7b2ffe22c88d7a48ca78c7102b4780210a 100644 (file)
@@ -34,7 +34,11 @@ static int nvdimm_probe(struct device *dev)
                return rc;
        }
 
-       /* reset locked, to be validated below... */
+       /*
+        * The locked status bit reflects explicit status codes from the
+        * label reading commands, revalidate it each time the driver is
+        * activated and re-reads the label area.
+        */
        nvdimm_clear_locked(dev);
 
        ndd = kzalloc(sizeof(*ndd), GFP_KERNEL);
@@ -51,6 +55,16 @@ static int nvdimm_probe(struct device *dev)
        get_device(dev);
        kref_init(&ndd->kref);
 
+       /*
+        * Attempt to unlock, if the DIMM supports security commands,
+        * otherwise the locked indication is determined by explicit
+        * status codes from the label reading commands.
+        */
+       rc = nvdimm_security_unlock(dev);
+       if (rc < 0)
+               dev_err(dev, "failed to unlock dimm: %d\n", rc);
+
+
        /*
         * EACCES failures reading the namespace label-area-properties
         * are interpreted as the DIMM capacity being locked but the
index e79cc8e5c1143807d3482ec2254b123f57e134df..cfde992684e7db07de208b94b0f4b382e59701d3 100644 (file)
@@ -250,6 +250,14 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
 void nvdimm_set_aliasing(struct device *dev);
 void nvdimm_set_locked(struct device *dev);
 void nvdimm_clear_locked(struct device *dev);
+#if IS_ENABLED(CONFIG_NVDIMM_KEYS)
+int nvdimm_security_unlock(struct device *dev);
+#else
+static inline int nvdimm_security_unlock(struct device *dev)
+{
+       return 0;
+}
+#endif
 struct nd_btt *to_nd_btt(struct device *dev);
 
 struct nd_gen_sb {
diff --git a/drivers/nvdimm/security.c b/drivers/nvdimm/security.c
new file mode 100644 (file)
index 0000000..51d77a6
--- /dev/null
@@ -0,0 +1,148 @@
+// 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"
+
+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)
+{
+       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_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 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;
+}
index 42c815f97c026c23423f6da11321e99b741668f5..0f0ab276134e52f0e7ca8f6146e0c9ed80837639 100644 (file)
@@ -163,9 +163,21 @@ enum nvdimm_security_state {
        NVDIMM_SECURITY_OVERWRITE,
 };
 
+#define NVDIMM_PASSPHRASE_LEN          32
+#define NVDIMM_KEY_DESC_LEN            22
+
+struct nvdimm_key_data {
+       u8 data[NVDIMM_PASSPHRASE_LEN];
+};
+
 struct nvdimm_security_ops {
        enum nvdimm_security_state (*state)(struct nvdimm *nvdimm);
        int (*freeze)(struct nvdimm *nvdimm);
+       int (*change_key)(struct nvdimm *nvdimm,
+                       const struct nvdimm_key_data *old_data,
+                       const struct nvdimm_key_data *new_data);
+       int (*unlock)(struct nvdimm *nvdimm,
+                       const struct nvdimm_key_data *key_data);
 };
 
 void badrange_init(struct badrange *badrange);
index 4a2f3cff2a75281261bced7657a73274f4aad4f6..33ea4077720519482137699239fda6325bbb097b 100644 (file)
@@ -80,6 +80,7 @@ libnvdimm-$(CONFIG_ND_CLAIM) += $(NVDIMM_SRC)/claim.o
 libnvdimm-$(CONFIG_BTT) += $(NVDIMM_SRC)/btt_devs.o
 libnvdimm-$(CONFIG_NVDIMM_PFN) += $(NVDIMM_SRC)/pfn_devs.o
 libnvdimm-$(CONFIG_NVDIMM_DAX) += $(NVDIMM_SRC)/dax_devs.o
+libnvdimm-$(CONFIG_NVDIMM_KEYS) += $(NVDIMM_SRC)/security.o
 libnvdimm-y += libnvdimm_test.o
 libnvdimm-y += config_check.o