From: Gaurav Kashyap <quic_gaurkash@xxxxxxxxxxx>
Add helper functions for the SCM calls required to support
hardware-wrapped inline storage encryption keys. These SCM calls manage
wrapped keys via Qualcomm's Hardware Key Manager (HWKM), which can only
be accessed from TrustZone.
QCOM_SCM_ES_GENERATE_ICE_KEY and QCOM_SCM_ES_IMPORT_ICE_KEY create a new
long-term wrapped key, with the former making the hardware generate the
key and the latter importing a raw key. QCOM_SCM_ES_PREPARE_ICE_KEY
converts the key to ephemerally-wrapped form so that it can be used for
inline storage encryption. These are planned to be wired up to new
ioctls via the blk-crypto framework; see the proposed documentation for
the hardware-wrapped keys feature for more information.
Similarly there's also QCOM_SCM_ES_DERIVE_SW_SECRET which derives a
"software secret" from an ephemerally-wrapped key and will be wired up
to the corresponding operation in the blk_crypto_profile.
These will all be used by the ICE driver in drivers/soc/qcom/ice.c.
Signed-off-by: Gaurav Kashyap <quic_gaurkash@xxxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
[EB: merged related patches, fixed error handling, fixed naming, fixed
docs for size parameters, fixed qcom_scm_has_wrapped_key_support(),
improved comments, improved commit message.]
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
drivers/firmware/qcom/qcom_scm.c | 214 +++++++++++++++++++++++++
drivers/firmware/qcom/qcom_scm.h | 4 +
include/linux/firmware/qcom/qcom_scm.h | 8 +
3 files changed, 226 insertions(+)
diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 72bf87ddcd96..36f3ddcb9020 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -1277,10 +1277,224 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
return ret;
}
EXPORT_SYMBOL_GPL(qcom_scm_ice_set_key);
+bool qcom_scm_has_wrapped_key_support(void)
+{
+ return __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_DERIVE_SW_SECRET) &&
+ __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_GENERATE_ICE_KEY) &&
+ __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_PREPARE_ICE_KEY) &&
+ __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+ QCOM_SCM_ES_IMPORT_ICE_KEY);
+}
+EXPORT_SYMBOL_GPL(qcom_scm_has_wrapped_key_support);
+
+/**
+ * qcom_scm_derive_sw_secret() - Derive software secret from wrapped key
+ * @eph_key: an ephemerally-wrapped key
+ * @eph_key_size: size of @eph_key in bytes
+ * @sw_secret: output buffer for the software secret
+ * @sw_secret_size: size of the software secret to derive in bytes
+ *
+ * Derive a software secret from an ephemerally-wrapped key for software crypto
+ * operations. This is done by calling into the secure execution environment,
+ * which then calls into the hardware to unwrap and derive the secret.
+ *
+ * For more information on sw_secret, see the "Hardware-wrapped keys" section of
+ * Documentation/block/inline-encryption.rst.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_derive_sw_secret(const u8 *eph_key, size_t eph_key_size,
+ u8 *sw_secret, size_t sw_secret_size)
+{
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_ES,
+ .cmd = QCOM_SCM_ES_DERIVE_SW_SECRET,
+ .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RW, QCOM_SCM_VAL,
+ QCOM_SCM_RW, QCOM_SCM_VAL),
+ .owner = ARM_SMCCC_OWNER_SIP,
+ };
+ int ret;
+
+ void *eph_key_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ eph_key_size,
+ GFP_KERNEL);
+ if (!eph_key_buf)
+ return -ENOMEM;
+
+ void *sw_secret_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ sw_secret_size,
+ GFP_KERNEL);
+ if (!sw_secret_buf)
+ return -ENOMEM;
+
+ memcpy(eph_key_buf, eph_key, eph_key_size);
+ desc.args[0] = qcom_tzmem_to_phys(eph_key_buf);
+ desc.args[1] = eph_key_size;
+ desc.args[2] = qcom_tzmem_to_phys(sw_secret_buf);
+ desc.args[3] = sw_secret_size;
+
+ ret = qcom_scm_call(__scm->dev, &desc, NULL);
+ if (!ret)
+ memcpy(sw_secret, sw_secret_buf, sw_secret_size);
+
+ memzero_explicit(eph_key_buf, eph_key_size);
+ memzero_explicit(sw_secret_buf, sw_secret_size);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_derive_sw_secret);
+
+/**
+ * qcom_scm_generate_ice_key() - Generate a wrapped key for storage encryption
+ * @lt_key: output buffer for the long-term wrapped key
+ * @lt_key_size: size of @lt_key in bytes. Must be the exact wrapped key size
+ * used by the SoC.
+ *
+ * Generate a key using the built-in HW module in the SoC. The resulting key is
+ * returned wrapped with the platform-specific Key Encryption Key.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_generate_ice_key(u8 *lt_key, size_t lt_key_size)
+{
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_ES,
+ .cmd = QCOM_SCM_ES_GENERATE_ICE_KEY,
+ .arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, QCOM_SCM_VAL),
+ .owner = ARM_SMCCC_OWNER_SIP,
+ };
+ int ret;
+
+ void *lt_key_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ lt_key_size,
+ GFP_KERNEL);
+ if (!lt_key_buf)
+ return -ENOMEM;
+
+ desc.args[0] = qcom_tzmem_to_phys(lt_key_buf);
+ desc.args[1] = lt_key_size;
+
+ ret = qcom_scm_call(__scm->dev, &desc, NULL);
+ if (!ret)
+ memcpy(lt_key, lt_key_buf, lt_key_size);
+
+ memzero_explicit(lt_key_buf, lt_key_size);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_generate_ice_key);
+
+/**
+ * qcom_scm_prepare_ice_key() - Re-wrap a key with the per-boot ephemeral key
+ * @lt_key: a long-term wrapped key
+ * @lt_key_size: size of @lt_key in bytes
+ * @eph_key: output buffer for the ephemerally-wrapped key
+ * @eph_key_size: size of @eph_key in bytes. Must be the exact wrapped key size
+ * used by the SoC.
+ *
+ * Given a long-term wrapped key, re-wrap it with the per-boot ephemeral key for
+ * added protection. The resulting key will only be valid for the current boot.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_prepare_ice_key(const u8 *lt_key, size_t lt_key_size,
+ u8 *eph_key, size_t eph_key_size)
+{
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_ES,
+ .cmd = QCOM_SCM_ES_PREPARE_ICE_KEY,
+ .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, QCOM_SCM_VAL,
+ QCOM_SCM_RW, QCOM_SCM_VAL),
+ .owner = ARM_SMCCC_OWNER_SIP,
+ };
+ int ret;
+
+ void *lt_key_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ lt_key_size,
+ GFP_KERNEL);
+ if (!lt_key_buf)
+ return -ENOMEM;
+
+ void *eph_key_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ eph_key_size,
+ GFP_KERNEL);
+ if (!eph_key_buf)
+ return -ENOMEM;
+
+ memcpy(lt_key_buf, lt_key, lt_key_size);
+ desc.args[0] = qcom_tzmem_to_phys(lt_key_buf);
+ desc.args[1] = lt_key_size;
+ desc.args[2] = qcom_tzmem_to_phys(eph_key_buf);
+ desc.args[3] = eph_key_size;
+
+ ret = qcom_scm_call(__scm->dev, &desc, NULL);
+ if (!ret)
+ memcpy(eph_key, eph_key_buf, eph_key_size);
+
+ memzero_explicit(lt_key_buf, lt_key_size);
+ memzero_explicit(eph_key_buf, eph_key_size);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_prepare_ice_key);
+
+/**
+ * qcom_scm_import_ice_key() - Import key for storage encryption
+ * @raw_key: the raw key to import
+ * @raw_key_size: size of @raw_key in bytes
+ * @lt_key: output buffer for the long-term wrapped key
+ * @lt_key_size: size of @lt_key in bytes. Must be the exact wrapped key size
+ * used by the SoC.
+ *
+ * Import a raw key and return a long-term wrapped key. Uses the SoC's HWKM to
+ * wrap the raw key using the platform-specific Key Encryption Key.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+int qcom_scm_import_ice_key(const u8 *raw_key, size_t raw_key_size,
+ u8 *lt_key, size_t lt_key_size)
+{
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_ES,
+ .cmd = QCOM_SCM_ES_IMPORT_ICE_KEY,
+ .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, QCOM_SCM_VAL,
+ QCOM_SCM_RW, QCOM_SCM_VAL),
+ .owner = ARM_SMCCC_OWNER_SIP,
+ };
+ int ret;
+
+ void *raw_key_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ raw_key_size,
+ GFP_KERNEL);
+ if (!raw_key_buf)
+ return -ENOMEM;
+
+ void *lt_key_buf __free(qcom_tzmem) = qcom_tzmem_alloc(__scm->mempool,
+ lt_key_size,
+ GFP_KERNEL);
+ if (!lt_key_buf)
+ return -ENOMEM;
+
+ memcpy(raw_key_buf, raw_key, raw_key_size);
+ desc.args[0] = qcom_tzmem_to_phys(raw_key_buf);
+ desc.args[1] = raw_key_size;
+ desc.args[2] = qcom_tzmem_to_phys(lt_key_buf);
+ desc.args[3] = lt_key_size;
+
+ ret = qcom_scm_call(__scm->dev, &desc, NULL);
+ if (!ret)
+ memcpy(lt_key, lt_key_buf, lt_key_size);
+
+ memzero_explicit(raw_key_buf, raw_key_size);
+ memzero_explicit(lt_key_buf, lt_key_size);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_scm_import_ice_key);
+
/**
* qcom_scm_hdcp_available() - Check if secure environment supports HDCP.
*
* Return true if HDCP is supported, false if not.
*/
diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h
index e36b2f67607f..097369d38b84 100644
--- a/drivers/firmware/qcom/qcom_scm.h
+++ b/drivers/firmware/qcom/qcom_scm.h
@@ -126,10 +126,14 @@ struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
#define QCOM_SCM_OCMEM_UNLOCK_CMD 0x02
#define QCOM_SCM_SVC_ES 0x10 /* Enterprise Security */
#define QCOM_SCM_ES_INVALIDATE_ICE_KEY 0x03
#define QCOM_SCM_ES_CONFIG_SET_ICE_KEY 0x04
+#define QCOM_SCM_ES_DERIVE_SW_SECRET 0x07
+#define QCOM_SCM_ES_GENERATE_ICE_KEY 0x08
+#define QCOM_SCM_ES_PREPARE_ICE_KEY 0x09
+#define QCOM_SCM_ES_IMPORT_ICE_KEY 0x0a
#define QCOM_SCM_SVC_HDCP 0x11
#define QCOM_SCM_HDCP_INVOKE 0x01
#define QCOM_SCM_SVC_LMH 0x13
diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
index 4621aec0328c..983e1591bbba 100644
--- a/include/linux/firmware/qcom/qcom_scm.h
+++ b/include/linux/firmware/qcom/qcom_scm.h
@@ -103,10 +103,18 @@ int qcom_scm_ocmem_unlock(enum qcom_scm_ocmem_client id, u32 offset, u32 size);
bool qcom_scm_ice_available(void);
int qcom_scm_ice_invalidate_key(u32 index);
int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
enum qcom_scm_ice_cipher cipher, u32 data_unit_size);
+bool qcom_scm_has_wrapped_key_support(void);
+int qcom_scm_derive_sw_secret(const u8 *eph_key, size_t eph_key_size,
+ u8 *sw_secret, size_t sw_secret_size);
+int qcom_scm_generate_ice_key(u8 *lt_key, size_t lt_key_size);
+int qcom_scm_prepare_ice_key(const u8 *lt_key, size_t lt_key_size,
+ u8 *eph_key, size_t eph_key_size);
+int qcom_scm_import_ice_key(const u8 *raw_key, size_t raw_key_size,
+ u8 *lt_key, size_t lt_key_size);
bool qcom_scm_hdcp_available(void);
int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);
int qcom_scm_iommu_set_pt_format(u32 sec_id, u32 ctx_num, u32 pt_fmt);
--
2.47.1
