Return-Path: Received: from mail-pl1-f195.google.com ([209.85.214.195]:33298 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730453AbeL0LIT (ORCPT ); Thu, 27 Dec 2018 06:08:19 -0500 Received: by mail-pl1-f195.google.com with SMTP id z23so8670295plo.0 for ; Thu, 27 Dec 2018 03:08:18 -0800 (PST) From: Sumit Garg To: linux-crypto@vger.kernel.org, devicetree@vger.kernel.org Cc: mpm@selenic.com, herbert@gondor.apana.org.au, robh+dt@kernel.org, mark.rutland@arm.com, arnd@arndb.de, gregkh@linuxfoundation.org, jens.wiklander@linaro.org, daniel.thompson@linaro.org, ard.biesheuvel@linaro.org, bhsharma@redhat.com, tee-dev@lists.linaro.org, Sumit Garg Subject: [PATCH v1 2/2] hwrng: add OP-TEE based rng driver Date: Thu, 27 Dec 2018 16:37:11 +0530 Message-Id: <1545908831-25910-3-git-send-email-sumit.garg@linaro.org> In-Reply-To: <1545908831-25910-1-git-send-email-sumit.garg@linaro.org> References: <1545908831-25910-1-git-send-email-sumit.garg@linaro.org> Sender: linux-crypto-owner@vger.kernel.org List-ID: On ARM SoC's with TrustZone enabled, peripherals like entropy sources might not be accessible to normal world (linux in this case) and rather accessible to secure world (OP-TEE in this case) only. So this driver aims to provides a generic interface to OP-TEE based random number generator service. Signed-off-by: Sumit Garg --- MAINTAINERS | 5 + drivers/char/hw_random/Kconfig | 15 ++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/optee-rng.c | 273 +++++++++++++++++++++++++++++++++++++ 4 files changed, 294 insertions(+) create mode 100644 drivers/char/hw_random/optee-rng.c diff --git a/MAINTAINERS b/MAINTAINERS index 0767f1d..fe0fb74 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11100,6 +11100,11 @@ M: Jens Wiklander S: Maintained F: drivers/tee/optee/ +OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER +M: Sumit Garg +S: Maintained +F: drivers/char/hw_random/optee-rng.c + OPA-VNIC DRIVER M: Dennis Dalessandro M: Niranjana Vishwanathapura diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index dac895d..25a7d8f 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -424,6 +424,21 @@ config HW_RANDOM_EXYNOS will be called exynos-trng. If unsure, say Y. + +config HW_RANDOM_OPTEE + tristate "OP-TEE based Random Number Generator support" + depends on OPTEE + default HW_RANDOM + help + This driver provides support for OP-TEE based Random Number + Generator on ARM SoCs where hardware entropy sources are not + accessible to normal world (Linux). + + To compile this driver as a module, choose M here: the module + will be called optee-rng. + + If unsure, say Y. + endif # HW_RANDOM config UML_RANDOM diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index e35ec3c..7c9ef4a 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -38,3 +38,4 @@ obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o obj-$(CONFIG_HW_RANDOM_S390) += s390-trng.o obj-$(CONFIG_HW_RANDOM_KEYSTONE) += ks-sa-rng.o +obj-$(CONFIG_HW_RANDOM_OPTEE) += optee-rng.o diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c new file mode 100644 index 0000000..8c63730 --- /dev/null +++ b/drivers/char/hw_random/optee-rng.c @@ -0,0 +1,273 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Linaro Ltd. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define TEE_ERROR_HEALTH_TEST_FAIL 0x00000001 + +/* + * TA_CMD_GET_ENTROPY - Get Entropy from RNG + * + * param[0] (inout memref) - Entropy buffer memory reference + * param[1] unused + * param[2] unused + * param[3] unused + * + * Result: + * TEE_SUCCESS - Invoke command success + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param + * TEE_ERROR_NOT_SUPPORTED - Requested entropy size greater than size of pool + * TEE_ERROR_HEALTH_TEST_FAIL - Continuous health testing failed + */ +#define TA_CMD_GET_ENTROPY 0x0 + +/* + * TA_CMD_GET_RNG_INFO - Get RNG information + * + * param[0] (out value) - value.a: RNG data-rate in bytes per second + * value.b: Quality/Entropy per 1024 bit of data + * param[1] unused + * param[2] unused + * param[3] unused + * + * Result: + * TEE_SUCCESS - Invoke command success + * TEE_ERROR_BAD_PARAMETERS - Incorrect input param + */ +#define TA_CMD_GET_RNG_INFO 0x1 + +#define MAX_ENTROPY_REQ_SZ (4 * 1024) + +static struct tee_context *ctx; +static struct tee_shm *entropy_shm_pool; +static u32 ta_rng_data_rate; +static u32 ta_rng_seesion_id; + +static size_t get_optee_rng_data(void *buf, size_t req_size) +{ + u32 ret = 0; + u8 *rng_data = NULL; + size_t rng_size = 0; + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct tee_param param[4] = {0}; + + /* Invoke TA_CMD_GET_RNG function of Trusted App */ + inv_arg.func = TA_CMD_GET_ENTROPY; + inv_arg.session = ta_rng_seesion_id; + inv_arg.num_params = 4; + + /* Fill invoke cmd params */ + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT; + param[0].u.memref.shm = entropy_shm_pool; + param[0].u.memref.size = req_size; + param[0].u.memref.shm_offs = 0; + + ret = tee_client_invoke_func(ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + pr_err("TA_CMD_GET_ENTROPY invoke function error: %x\n", + inv_arg.ret); + return 0; + } + + rng_data = tee_shm_get_va(entropy_shm_pool, 0); + if (IS_ERR(rng_data)) { + pr_err("tee_shm_get_va failed\n"); + return 0; + } + + rng_size = param[0].u.memref.size; + memcpy(buf, rng_data, rng_size); + + return rng_size; +} + +static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) +{ + u8 *data = buf; + size_t read = 0, rng_size = 0; + int timeout = 1; + + if (max > MAX_ENTROPY_REQ_SZ) + max = MAX_ENTROPY_REQ_SZ; + + while (read == 0) { + rng_size = get_optee_rng_data(data, (max - read)); + + data += rng_size; + read += rng_size; + + if (wait) { + if (timeout-- == 0) + return read; + msleep((1000 * (max - read)) / ta_rng_data_rate); + } else { + return read; + } + } + + return read; +} + +static int optee_rng_init(struct hwrng *rng) +{ + entropy_shm_pool = tee_shm_alloc(ctx, MAX_ENTROPY_REQ_SZ, + TEE_SHM_MAPPED | TEE_SHM_DMA_BUF); + if (IS_ERR(entropy_shm_pool)) { + pr_err("tee_shm_alloc failed\n"); + return PTR_ERR(entropy_shm_pool); + } + + return 0; +} + +static void optee_rng_cleanup(struct hwrng *rng) +{ + tee_shm_free(entropy_shm_pool); +} + +static struct hwrng optee_rng = { + .name = "optee-rng", + .init = optee_rng_init, + .cleanup = optee_rng_cleanup, + .read = optee_rng_read, +}; + +static const struct of_device_id optee_match[] = { + { .compatible = "linaro,optee-tz" }, + {}, +}; + +static int get_optee_rng_uuid(uuid_t *ta_rng_uuid) +{ + struct device_node *fw_np; + struct device_node *np; + const char *uuid; + + /* Node is supposed to be below /firmware */ + fw_np = of_find_node_by_name(NULL, "firmware"); + if (!fw_np) + return -ENODEV; + + np = of_find_matching_node(fw_np, optee_match); + if (!np || !of_device_is_available(np)) + return -ENODEV; + + if (of_property_read_string(np, "rng-uuid", &uuid)) { + pr_warn("missing \"uuid\" property\n"); + return -ENXIO; + } + + if (uuid_parse(uuid, ta_rng_uuid)) { + pr_warn("incorrect rng ta uuid\n"); + return -EINVAL; + } + + return 0; +} + +static int get_optee_rng_info(void) +{ + u32 ret = 0; + struct tee_ioctl_invoke_arg inv_arg = {0}; + struct tee_param param[4] = {0}; + + /* Invoke TA_CMD_GET_RNG function of Trusted App */ + inv_arg.func = TA_CMD_GET_RNG_INFO; + inv_arg.session = ta_rng_seesion_id; + inv_arg.num_params = 4; + + /* Fill invoke cmd params */ + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT; + + ret = tee_client_invoke_func(ctx, &inv_arg, param); + if ((ret < 0) || (inv_arg.ret != 0)) { + pr_err("TA_CMD_GET_RNG_INFO invoke function error: %x\n", + inv_arg.ret); + return -EINVAL; + } + + ta_rng_data_rate = param[0].u.value.a; + optee_rng.quality = param[0].u.value.b; + + return 0; +} + +static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data) +{ + if (ver->impl_id == TEE_IMPL_ID_OPTEE) + return 1; + else + return 0; +} + +static int __init mod_init(void) +{ + int ret = 0, err = -ENODEV; + struct tee_ioctl_open_session_arg sess_arg = {0}; + uuid_t ta_rng_uuid = {0}; + + err = get_optee_rng_uuid(&ta_rng_uuid); + if (err) + return err; + + /* Open context with TEE driver */ + ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL); + if (IS_ERR(ctx)) + return -ENODEV; + + /* Open session with hwrng Trusted App */ + memcpy(sess_arg.uuid, ta_rng_uuid.b, TEE_IOCTL_UUID_LEN); + sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC; + sess_arg.num_params = 0; + + ret = tee_client_open_session(ctx, &sess_arg, NULL); + if ((ret < 0) || (sess_arg.ret != 0)) { + pr_err("tee_client_open_session failed, error: %x\n", + sess_arg.ret); + err = -EINVAL; + goto out_ctx; + } + ta_rng_seesion_id = sess_arg.session; + + err = get_optee_rng_info(); + if (err) + goto out_sess; + + err = hwrng_register(&optee_rng); + if (err) { + pr_err("registering failed (%d)\n", err); + goto out_sess; + } + + return 0; + +out_sess: + tee_client_close_session(ctx, ta_rng_seesion_id); +out_ctx: + tee_client_close_context(ctx); + + return err; +} + +static void __exit mod_exit(void) +{ + tee_client_close_session(ctx, ta_rng_seesion_id); + tee_client_close_context(ctx); + hwrng_unregister(&optee_rng); +} + +module_init(mod_init); +module_exit(mod_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sumit Garg "); +MODULE_DESCRIPTION("OP-TEE based random number generator driver"); +MODULE_SOFTDEP("pre: optee"); -- 2.7.4