diff options
Diffstat (limited to 'drivers/firmware/qcom/qcom_scm.c')
| -rw-r--r-- | drivers/firmware/qcom/qcom_scm.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c index 2380775508ac..f0569bb9411f 100644 --- a/drivers/firmware/qcom/qcom_scm.c +++ b/drivers/firmware/qcom/qcom_scm.c @@ -1282,6 +1282,220 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size, } 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. * |