From patchwork Tue Jul 7 03:01:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11647447 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7B27014E3 for ; Tue, 7 Jul 2020 03:05:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63F8E2070C for ; Tue, 7 Jul 2020 03:05:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727831AbgGGDF1 (ORCPT ); Mon, 6 Jul 2020 23:05:27 -0400 Received: from mga11.intel.com ([192.55.52.93]:35863 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726869AbgGGDF0 (ORCPT ); Mon, 6 Jul 2020 23:05:26 -0400 IronPort-SDR: ikc1fUcfDzhhylFBA6/oMZOZe9upAvJCY7CUYVmJ66wZgBabXENKiPduDD6KEzgYKO6Ld3HgZH GVQVFqqOcSAA== X-IronPort-AV: E=McAfee;i="6000,8403,9674"; a="145632006" X-IronPort-AV: E=Sophos;i="5.75,321,1589266800"; d="scan'208";a="145632006" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2020 20:05:25 -0700 IronPort-SDR: LHqi0812G2a6+wqKMx2/fhwzgijeCdHRxhPq3Y3UJOtfvTV7UHJ5ORBEiSsNwdO19i/hMIX5w5 OjYjZYdQoHPA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,321,1589266800"; d="scan'208";a="388368710" Received: from apiccion-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.45.178]) by fmsmga001.fm.intel.com with ESMTP; 06 Jul 2020 20:05:14 -0700 From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jarkko Sakkinen , linux-security-module@vger.kernel.org, Jethro Beekman , Andy Lutomirski , akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, sean.j.christopherson@intel.com, tglx@linutronix.de, yaozhangx@google.com Subject: [PATCH v34 15/24] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Date: Tue, 7 Jul 2020 06:01:55 +0300 Message-Id: <20200707030204.126021-16-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200707030204.126021-1-jarkko.sakkinen@linux.intel.com> References: <20200707030204.126021-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Provisioning Certification Enclave (PCE), the root of trust for other enclaves, generates a signing key from a fused key called Provisioning Certification Key. PCE can then use this key to certify an attestation key of a Quoting Enclave (QE), e.g. we get the chain of trust down to the hardware if the Intel signed PCE is used. To use the needed keys, ATTRIBUTE.PROVISIONKEY is required but should be only allowed for those who actually need it so that only the trusted parties can certify QE's. Obviously the attestation service should know the public key of the used PCE and that way detect illegit attestation, but whitelisting the legit users still adds an additional layer of defence. Add new device file called /dev/sgx/provision. The sole purpose of this file is to provide file descriptors that act as privilege tokens to allow to build enclaves with ATTRIBUTE.PROVISIONKEY set. A new ioctl called SGX_IOC_ENCLAVE_SET_ATTRIBUTE is used to assign this token to an enclave. Cc: linux-security-module@vger.kernel.org Acked-by: Jethro Beekman Suggested-by: Andy Lutomirski Signed-off-by: Jarkko Sakkinen --- arch/x86/include/uapi/asm/sgx.h | 11 ++++++++ arch/x86/kernel/cpu/sgx/driver.c | 18 ++++++++++++ arch/x86/kernel/cpu/sgx/driver.h | 2 ++ arch/x86/kernel/cpu/sgx/ioctl.c | 47 ++++++++++++++++++++++++++++++++ 4 files changed, 78 insertions(+) diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h index 5edb08ab8fd0..57d0d30c79b3 100644 --- a/arch/x86/include/uapi/asm/sgx.h +++ b/arch/x86/include/uapi/asm/sgx.h @@ -25,6 +25,8 @@ enum sgx_page_flags { _IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages) #define SGX_IOC_ENCLAVE_INIT \ _IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init) +#define SGX_IOC_ENCLAVE_SET_ATTRIBUTE \ + _IOW(SGX_MAGIC, 0x03, struct sgx_enclave_set_attribute) /** * struct sgx_enclave_create - parameter structure for the @@ -63,4 +65,13 @@ struct sgx_enclave_init { __u64 sigstruct; }; +/** + * struct sgx_enclave_set_attribute - parameter structure for the + * %SGX_IOC_ENCLAVE_SET_ATTRIBUTE ioctl + * @attribute_fd: file handle of the attribute file in the securityfs + */ +struct sgx_enclave_set_attribute { + __u64 attribute_fd; +}; + #endif /* _UAPI_ASM_X86_SGX_H */ diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c index 20c3254675e9..1cebb6e9c9b7 100644 --- a/arch/x86/kernel/cpu/sgx/driver.c +++ b/arch/x86/kernel/cpu/sgx/driver.c @@ -139,6 +139,10 @@ static const struct file_operations sgx_encl_fops = { .get_unmapped_area = sgx_get_unmapped_area, }; +const struct file_operations sgx_provision_fops = { + .owner = THIS_MODULE, +}; + static struct miscdevice sgx_dev_enclave = { .minor = MISC_DYNAMIC_MINOR, .name = "enclave", @@ -146,6 +150,13 @@ static struct miscdevice sgx_dev_enclave = { .fops = &sgx_encl_fops, }; +static struct miscdevice sgx_dev_provision = { + .minor = MISC_DYNAMIC_MINOR, + .name = "provision", + .nodename = "sgx/provision", + .fops = &sgx_provision_fops, +}; + int __init sgx_drv_init(void) { unsigned int eax, ebx, ecx, edx; @@ -186,5 +197,12 @@ int __init sgx_drv_init(void) return ret; } + ret = misc_register(&sgx_dev_provision); + if (ret) { + pr_err("Creating /dev/sgx/provision failed with %d.\n", ret); + misc_deregister(&sgx_dev_enclave); + return ret; + } + return 0; } diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h index e4063923115b..72747d01c046 100644 --- a/arch/x86/kernel/cpu/sgx/driver.h +++ b/arch/x86/kernel/cpu/sgx/driver.h @@ -23,6 +23,8 @@ extern u64 sgx_attributes_reserved_mask; extern u64 sgx_xfrm_reserved_mask; extern u32 sgx_xsave_size_tbl[64]; +extern const struct file_operations sgx_provision_fops; + long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg); int sgx_drv_init(void); diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index b5c021147937..e4ec07a56d39 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -670,6 +670,50 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg) return ret; } +/** + * sgx_ioc_enclave_set_attribute - handler for %SGX_IOC_ENCLAVE_SET_ATTRIBUTE + * @filep: open file to /dev/sgx + * @arg: userspace pointer to a struct sgx_enclave_set_attribute instance + * + * Mark the enclave as being allowed to access a restricted attribute bit. + * The requested attribute is specified via the attribute_fd field in the + * provided struct sgx_enclave_set_attribute. The attribute_fd must be a + * handle to an SGX attribute file, e.g. "/dev/sgx/provision". + * + * Failure to explicitly request access to a restricted attribute will cause + * sgx_ioc_enclave_init() to fail. Currently, the only restricted attribute + * is access to the PROVISION_KEY. + * + * Note, access to the EINITTOKEN_KEY is disallowed entirely. + * + * Return: 0 on success, -errno otherwise + */ +static long sgx_ioc_enclave_set_attribute(struct sgx_encl *encl, + void __user *arg) +{ + struct sgx_enclave_set_attribute params; + struct file *attribute_file; + int ret; + + if (copy_from_user(¶ms, arg, sizeof(params))) + return -EFAULT; + + attribute_file = fget(params.attribute_fd); + if (!attribute_file) + return -EINVAL; + + if (attribute_file->f_op != &sgx_provision_fops) { + ret = -EINVAL; + goto out; + } + + encl->allowed_attributes |= SGX_ATTR_PROVISIONKEY; + ret = 0; + +out: + fput(attribute_file); + return ret; +} long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) { @@ -690,6 +734,9 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) case SGX_IOC_ENCLAVE_INIT: ret = sgx_ioc_enclave_init(encl, (void __user *)arg); break; + case SGX_IOC_ENCLAVE_SET_ATTRIBUTE: + ret = sgx_ioc_enclave_set_attribute(encl, (void __user *)arg); + break; default: ret = -ENOIOCTLCMD; break;