From patchwork Wed Nov 22 05:38:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gaurav Kashyap (QUIC)" X-Patchwork-Id: 13464042 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="aLk+zLXk" Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67C9618C; Tue, 21 Nov 2023 21:40:10 -0800 (PST) Received: from pps.filterd (m0279868.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3AM4u8rG016527; Wed, 22 Nov 2023 05:40:08 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=qcppdkim1; bh=93z+vUlFL3zac8xz5d801XPSydcKKD4BdbQWC478ukc=; b=aLk+zLXkAYZoCQWC1L6y731KPJq3sFePbOZ3GezuZCJ1Rr69hJZ45XEv/ONzsF0AiO+0 M8kBtJAMEICOfB1BIg0B0UldaAMfiwSsun3urFIAol9Dju4J1ILEI7JZXgl9mBV5qb6g MufLM2xBSYBt2mbgYMtq8ACl4qRVkHJw/5jd87UBfpHRymLjIiEy16rXGihDoP1f6JDs IjMAmol8VsfI5myeLHMQmQMehI/dQGRY9QsRPiHQYpYZzhklbDDnP31L4vJ29JdbWZAQ KFo/RKrV92UE5q+sFQ+CfRBxcaCgXRFiAitDTTqUFSxDYd+vYjS+/ElBY07vdKpDoBlc 4w== Received: from nalasppmta03.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3ugr85u3e1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 22 Nov 2023 05:40:07 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA03.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 3AM5e6rD007072 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 22 Nov 2023 05:40:07 GMT Received: from hu-gaurkash-lv.qualcomm.com (10.49.16.6) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Tue, 21 Nov 2023 21:40:00 -0800 From: Gaurav Kashyap To: , , , , CC: , , , , , , , , Gaurav Kashyap Subject: [PATCH v3 02/12] qcom_scm: scm call for deriving a software secret Date: Tue, 21 Nov 2023 21:38:07 -0800 Message-ID: <20231122053817.3401748-3-quic_gaurkash@quicinc.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231122053817.3401748-1-quic_gaurkash@quicinc.com> References: <20231122053817.3401748-1-quic_gaurkash@quicinc.com> Precedence: bulk X-Mailing-List: linux-fscrypt@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: nalasex01a.na.qualcomm.com (10.47.209.196) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: 4DjbseLBP3oGwAVrR_P03XWZztbvUR2c X-Proofpoint-ORIG-GUID: 4DjbseLBP3oGwAVrR_P03XWZztbvUR2c X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-22_02,2023-11-21_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 impostorscore=0 phishscore=0 suspectscore=0 adultscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 mlxscore=0 clxscore=1015 mlxlogscore=799 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311060000 definitions=main-2311220040 Inline storage encryption requires deriving a sw secret from the hardware wrapped keys. For non-wrapped keys, this can be directly done as keys are in the clear. However, when keys are hardware wrapped, it can be unwrapped by HWKM (Hardware Key Manager) which is accessible only from Qualcomm Trustzone. Hence, it also makes sense that the software secret is also derived there and returned to the linux kernel . This can be invoked by using the crypto profile APIs provided by the block layer. Signed-off-by: Gaurav Kashyap --- drivers/firmware/qcom/qcom_scm.c | 71 ++++++++++++++++++++++++++ drivers/firmware/qcom/qcom_scm.h | 1 + include/linux/firmware/qcom/qcom_scm.h | 2 + 3 files changed, 74 insertions(+) diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c index 520de9b5633a..6dfb913f3e33 100644 --- a/drivers/firmware/qcom/qcom_scm.c +++ b/drivers/firmware/qcom/qcom_scm.c @@ -1214,6 +1214,77 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size, } EXPORT_SYMBOL_GPL(qcom_scm_ice_set_key); +/** + * qcom_scm_derive_sw_secret() - Derive software secret from wrapped key + * @wkey: the hardware wrapped key inaccessible to software + * @wkey_size: size of the wrapped key + * @sw_secret: the secret to be derived which is exactly the secret size + * @sw_secret_size: size of the sw_secret + * + * Derive a software secret from a hardware wrapped key for software crypto + * operations. + * For wrapped keys, the key needs to be unwrapped, in order to derive a + * software secret, which can be done in the hardware from a secure execution + * environment. + * + * For more information on sw secret, please refer to "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 *wkey, size_t wkey_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), + .args[1] = wkey_size, + .args[3] = sw_secret_size, + .owner = ARM_SMCCC_OWNER_SIP, + }; + + void *wkey_buf, *secret_buf; + dma_addr_t wkey_phys, secret_phys; + int ret; + + /* + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly + * get a physical address, while guaranteeing that we can zeroize the + * key material later using memzero_explicit(). + */ + wkey_buf = dma_alloc_coherent(__scm->dev, wkey_size, &wkey_phys, GFP_KERNEL); + if (!wkey_buf) + return -ENOMEM; + secret_buf = dma_alloc_coherent(__scm->dev, sw_secret_size, &secret_phys, GFP_KERNEL); + if (!secret_buf) { + ret = -ENOMEM; + goto err_free_wrapped; + } + + memcpy(wkey_buf, wkey, wkey_size); + desc.args[0] = wkey_phys; + desc.args[2] = secret_phys; + + ret = qcom_scm_call(__scm->dev, &desc, NULL); + if (!ret) + memcpy(sw_secret, secret_buf, sw_secret_size); + + memzero_explicit(secret_buf, sw_secret_size); + + dma_free_coherent(__scm->dev, sw_secret_size, secret_buf, secret_phys); + +err_free_wrapped: + memzero_explicit(wkey_buf, wkey_size); + + dma_free_coherent(__scm->dev, wkey_size, wkey_buf, wkey_phys); + + return ret; +} +EXPORT_SYMBOL(qcom_scm_derive_sw_secret); + /** * qcom_scm_hdcp_available() - Check if secure environment supports HDCP. * diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h index 4532907e8489..c75456aa6ac5 100644 --- a/drivers/firmware/qcom/qcom_scm.h +++ b/drivers/firmware/qcom/qcom_scm.h @@ -121,6 +121,7 @@ int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc, #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_SVC_HDCP 0x11 #define QCOM_SCM_HDCP_INVOKE 0x01 diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h index ccaf28846054..c65f2d61492d 100644 --- a/include/linux/firmware/qcom/qcom_scm.h +++ b/include/linux/firmware/qcom/qcom_scm.h @@ -103,6 +103,8 @@ 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); +int qcom_scm_derive_sw_secret(const u8 *wkey, size_t wkey_size, + u8 *sw_secret, size_t sw_secret_size); bool qcom_scm_hdcp_available(void); int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);