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[209.85.220.65]) by mx.google.com with SMTPS id c10sor33393663pgq.28.2018.12.20.02.17.00 for (Google Transport Security); Thu, 20 Dec 2018 02:17:00 -0800 (PST) Received-SPF: pass (google.com: domain of sumit.garg@linaro.org designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=JGq7F3Xo; spf=pass (google.com: domain of sumit.garg@linaro.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=sumit.garg@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=lmJ5zibTAVNRPPc6FEVhSaOZlC0eklES57rQGeEpEMs=; b=JGq7F3XosAyMbse4qmunxmQST+EUxN60RbAWSwxFGRQb55ZSsEEbCSbziK6lkZ71au Ib6yPrlaeFGHIKOyNNg2WJxU/WfeNSNiQSMG/uD7Ra6wPhWnIMIbpsSLcH+MRehxNjoN RX4/SBqn138EOYEA8X2quA0SfrUyrcJTZG2+c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=lmJ5zibTAVNRPPc6FEVhSaOZlC0eklES57rQGeEpEMs=; b=r6ybzhQq/TJlAy8ADApioSRH5acvd/xKvEHa0HT3y+J0w1OwX6Qnu2sNoE1tKB9Sus Jvw9kP2bNo/PK8GRB6vww7WUX1heSY3D10t6RN0uNfgvgAsRVdttKW+VlH8IM7qGNTmf s4625BXNxNLO+SR6i9WFmHUOaJ7U6656MjfrRP5lagkm5IxcWHX0zJXgOwDCvvNXmNCC Zo5wbr5UF6YMxPVo2Dkg7OZVY9rJa5Y+wRMRG1zQ7qMrD4b0cFrgvx7S08o10ZDEydx4 s4K8RL5PtALHs3WbFM9xhCfZF0DH/IfjjYswU53gVhh8dqGQlSEnJSGfYqtpH1HqPzZg 64Jw== X-Gm-Message-State: AA+aEWZ9tnskNlQdgpHs3Y54ufveo+1cuSPBYytxE5UDrg/b61dViRQu 7tACw5JK5yJTr6lVzRR/RfVnfF7c X-Google-Smtp-Source: AFSGD/WnutfzFF8Y6cT07zZfTzAZB9dFSdxuFLar2gCLSeuWu9l/bEfdJkxp8IzGPl3uZ/hA7jJWjw== X-Received: by 2002:a63:a452:: with SMTP id c18mr22859395pgp.204.1545301020299; Thu, 20 Dec 2018 02:17:00 -0800 (PST) Return-Path: Received: from localhost.localdomain ([117.196.232.175]) by smtp.gmail.com with ESMTPSA id f67sm44097089pff.29.2018.12.20.02.16.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 20 Dec 2018 02:16:59 -0800 (PST) From: Sumit Garg To: daniel.thompson@linaro.org Cc: patches@linaro.org, Sumit Garg Subject: [PATCH v2 2/2] hwrng: add OP-TEE based rng driver Date: Thu, 20 Dec 2018 15:46:38 +0530 Message-Id: <1545300998-10069-3-git-send-email-sumit.garg@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1545300998-10069-1-git-send-email-sumit.garg@linaro.org> References: <1545300998-10069-1-git-send-email-sumit.garg@linaro.org> 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 | 280 +++++++++++++++++++++++++++++++++++++ 4 files changed, 301 insertions(+) create mode 100644 drivers/char/hw_random/optee-rng.c -- 2.7.4 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..0dbe210 --- /dev/null +++ b/drivers/char/hw_random/optee-rng.c @@ -0,0 +1,280 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Linaro Ltd. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define PFX KBUILD_MODNAME ": " + +#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 + +/* + * PTA_CMD_GET_RNG_INFO - Get RNG information + * + * param[0] (out value) - value.a: RNG data-rate + * 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(PFX "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(PFX "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 = max / MAX_ENTROPY_REQ_SZ + 1; + + /* New random numbers are generated approximately 1byte per 2ms */ + while (read < max) { + if ((max - read) < MAX_ENTROPY_REQ_SZ) + rng_size = get_optee_rng_data(data, (max - read)); + else + rng_size = get_optee_rng_data(data, MAX_ENTROPY_REQ_SZ); + + data += rng_size; + read += rng_size; + + if (wait) { + if (timeout-- == 0) + return read; + if ((max - read) < MAX_ENTROPY_REQ_SZ) + msleep((1000 * (max - read)) / + ta_rng_data_rate); + else + msleep((1000 * MAX_ENTROPY_REQ_SZ) / + 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(PFX "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(PFX "missing \"uuid\" property\n"); + return -ENXIO; + } + + if (uuid_parse(uuid, ta_rng_uuid)) { + pr_warn(PFX "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(PFX "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 tee_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, tee_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(PFX "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(PFX " 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");