From patchwork Wed Oct 20 06:14:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dov Murik X-Patchwork-Id: 12571657 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B445DC433EF for ; Wed, 20 Oct 2021 06:14:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97FDF6136F for ; Wed, 20 Oct 2021 06:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229591AbhJTGRG (ORCPT ); Wed, 20 Oct 2021 02:17:06 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53076 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229715AbhJTGRE (ORCPT ); Wed, 20 Oct 2021 02:17:04 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 19K5gNdP015104; Wed, 20 Oct 2021 02:14:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=fGRye17iV9B/XxoNx8fhI19L3gsprfmWejtgtwWuGOQ=; b=sps6NDlHP9tA7dweUW1RC9h6zNOw67RZ0Xmy25bv+X20+f7pI9uzBn4HCvkotPH4v7Yo /nLT62KRXpYp/9QTx+7rfp5bEnRXBt/uNDuU5RrnFKzs23WvKMY5r0nserX78Jk7mb2G Q5CbRKNlazPpv5U3BAWLsFmuqOW8VhO5Chns1DEci1PKJxZ868+EaXTcQA5G6SJDbW1g CxZTNAqDhdEsh8uPBa/x3VuVfDXQRbZXfKoLkiAB3di3J5YRf/7NlYXCay0sLJJKECNj izKq/PjxkjJR0mwVKKZuoOOKdbzj2rn1ioyT7N/8X96i4V9MNbFVy5Gt3VJ9kiErZkuK /g== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 3btb5k2v7t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Oct 2021 02:14:27 -0400 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 19K4kmxR025311; Wed, 20 Oct 2021 02:14:26 -0400 Received: from ppma01dal.us.ibm.com (83.d6.3fa9.ip4.static.sl-reverse.com [169.63.214.131]) by mx0b-001b2d01.pphosted.com with ESMTP id 3btb5k2v7h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Oct 2021 02:14:26 -0400 Received: from pps.filterd (ppma01dal.us.ibm.com [127.0.0.1]) by ppma01dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 19K6C95h023406; Wed, 20 Oct 2021 06:14:25 GMT Received: from b01cxnp23034.gho.pok.ibm.com (b01cxnp23034.gho.pok.ibm.com [9.57.198.29]) by ppma01dal.us.ibm.com with ESMTP id 3bqpccf6qq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Oct 2021 06:14:25 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 19K6ENNM42926564 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Oct 2021 06:14:23 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 31811AC067; Wed, 20 Oct 2021 06:14:23 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CF970AC05F; Wed, 20 Oct 2021 06:14:22 +0000 (GMT) Received: from amdrome3.watson.ibm.com (unknown [9.2.130.16]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Wed, 20 Oct 2021 06:14:22 +0000 (GMT) From: Dov Murik To: linux-efi@vger.kernel.org Cc: Dov Murik , Borislav Petkov , Ashish Kalra , Brijesh Singh , Tom Lendacky , Ard Biesheuvel , James Morris , "Serge E. Hallyn" , Andi Kleen , Greg KH , Andrew Scull , Dave Hansen , "Dr. David Alan Gilbert" , James Bottomley , Tobin Feldman-Fitzthum , Jim Cadden , Daniele Buono , linux-coco@lists.linux.dev, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 1/3] efi/libstub: Copy confidential computing secret area Date: Wed, 20 Oct 2021 06:14:06 +0000 Message-Id: <20211020061408.3447533-2-dovmurik@linux.ibm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211020061408.3447533-1-dovmurik@linux.ibm.com> References: <20211020061408.3447533-1-dovmurik@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 3so5gxdGT4rYymXjOUkXoisozRchWFKs X-Proofpoint-ORIG-GUID: LRLCKAcO0HpGailTb4-Kh0vbhfo1wEBn X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.182.1,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.0.607.475 definitions=2021-10-20_02,2021-10-19_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 mlxscore=0 adultscore=0 spamscore=0 clxscore=1015 impostorscore=0 suspectscore=0 mlxlogscore=999 malwarescore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109230001 definitions=main-2110200032 Precedence: bulk List-ID: Confidential computing (coco) hardware such as AMD SEV (Secure Encrypted Virtualization) allows a guest owner to inject secrets into the VMs memory without the host/hypervisor being able to read them. Firmware support for secret injection is available in OVMF, which reserves a memory area for secret injection and includes a pointer to it the in EFI config table entry LINUX_EFI_COCO_SECRET_TABLE_GUID. However, OVMF doesn't force the guest OS to keep this memory area reserved. If EFI exposes such a table entry, efi/libstub will copy this area to a reserved memory for future use inside the kernel. A pointer to the new copy is kept in the EFI table under LINUX_EFI_COCO_SECRET_AREA_GUID. The new functionality can be enabled with CONFIG_EFI_COCO_SECRET=y. Signed-off-by: Dov Murik --- drivers/firmware/efi/Kconfig | 12 +++++ drivers/firmware/efi/libstub/Makefile | 1 + drivers/firmware/efi/libstub/coco.c | 68 +++++++++++++++++++++++++ drivers/firmware/efi/libstub/efi-stub.c | 2 + drivers/firmware/efi/libstub/efistub.h | 6 +++ drivers/firmware/efi/libstub/x86-stub.c | 2 + include/linux/efi.h | 6 +++ 7 files changed, 97 insertions(+) create mode 100644 drivers/firmware/efi/libstub/coco.c diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index 2c3dac5ecb36..68d1c5e6a7b5 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -284,3 +284,15 @@ config EFI_CUSTOM_SSDT_OVERLAYS See Documentation/admin-guide/acpi/ssdt-overlays.rst for more information. + +config EFI_COCO_SECRET + bool "Copy and reserve EFI Confidential Computing secret area" + depends on EFI + default n + help + Copy memory reserved by EFI for Confidential Computing (coco) + injected secrets, if EFI exposes such a table entry. + + If you say Y here, the EFI stub copy the EFI secret area (if + available) and reserve it for use inside the kernel. This will + allow the virt/coo/efi_secret module to access the secrets. diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index d0537573501e..fdada3fd5d9b 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -66,6 +66,7 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o fdt.o string.o \ $(patsubst %.c,lib-%.o,$(efi-deps-y)) +lib-$(CONFIG_EFI_COCO_SECRET) += coco.o lib-$(CONFIG_ARM) += arm32-stub.o lib-$(CONFIG_ARM64) += arm64-stub.o lib-$(CONFIG_X86) += x86-stub.o diff --git a/drivers/firmware/efi/libstub/coco.c b/drivers/firmware/efi/libstub/coco.c new file mode 100644 index 000000000000..bf546b6a3f72 --- /dev/null +++ b/drivers/firmware/efi/libstub/coco.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Confidential computing (coco) secret area handling + * + * Copyright (C) 2021 IBM Corporation + * Author: Dov Murik + */ + +#include +#include +#include + +#include "efistub.h" + +#define LINUX_EFI_COCO_SECRET_TABLE_GUID \ + EFI_GUID(0xadf956ad, 0xe98c, 0x484c, 0xae, 0x11, 0xb5, 0x1c, 0x7d, 0x33, 0x64, 0x47) + +/** + * struct efi_coco_secret_table - EFI config table that points to the + * confidential computing secret area. The guid + * LINUX_EFI_COCO_SECRET_TABLE_GUID holds this table. + * @base: Physical address of the EFI secret area + * @size: Size (in bytes) of the EFI secret area + */ +struct efi_coco_secret_table { + u64 base; + u64 size; +} __attribute((packed)); + +/* + * Create a copy of EFI's confidential computing secret area (if available) so + * that the secrets are accessible in the kernel after ExitBootServices. + */ +void efi_copy_coco_secret_area(void) +{ + efi_guid_t linux_secret_area_guid = LINUX_EFI_COCO_SECRET_AREA_GUID; + efi_status_t status; + struct efi_coco_secret_table *secret_table; + struct linux_efi_coco_secret_area *secret_area; + + secret_table = get_efi_config_table(LINUX_EFI_COCO_SECRET_TABLE_GUID); + if (!secret_table) + return; + + if (secret_table->size == 0 || secret_table->size >= SZ_4G) + return; + + /* Allocate space for the secret area and copy it */ + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, + sizeof(*secret_area) + secret_table->size, (void **)&secret_area); + + if (status != EFI_SUCCESS) { + efi_err("Unable to allocate memory for confidential computing secret area copy\n"); + return; + } + + secret_area->size = secret_table->size; + memcpy(secret_area->area, (void *)(unsigned long)secret_table->base, secret_table->size); + + status = efi_bs_call(install_configuration_table, &linux_secret_area_guid, secret_area); + if (status != EFI_SUCCESS) + goto err_free; + + return; + +err_free: + efi_bs_call(free_pool, secret_area); +} diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c index 26e69788f27a..18b3acd15c85 100644 --- a/drivers/firmware/efi/libstub/efi-stub.c +++ b/drivers/firmware/efi/libstub/efi-stub.c @@ -205,6 +205,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, efi_retrieve_tpm2_eventlog(); + efi_copy_coco_secret_area(); + /* Ask the firmware to clear memory on unclean shutdown */ efi_enable_reset_attack_mitigation(); diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index cde0a2ef507d..a23771547790 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -858,4 +858,10 @@ efi_enable_reset_attack_mitigation(void) { } void efi_retrieve_tpm2_eventlog(void); +#ifdef CONFIG_EFI_COCO_SECRET +void efi_copy_coco_secret_area(void); +#else +static inline void efi_copy_coco_secret_area(void) { } +#endif + #endif diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index f14c4ff5839f..4ad85e1b6191 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -793,6 +793,8 @@ unsigned long efi_main(efi_handle_t handle, efi_retrieve_tpm2_eventlog(); + efi_copy_coco_secret_area(); + setup_graphics(boot_params); setup_efi_pci(boot_params); diff --git a/include/linux/efi.h b/include/linux/efi.h index 6b5d36babfcc..9021dd521302 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -359,6 +359,7 @@ void efi_native_runtime_setup(void); #define LINUX_EFI_MEMRESERVE_TABLE_GUID EFI_GUID(0x888eb0c6, 0x8ede, 0x4ff5, 0xa8, 0xf0, 0x9a, 0xee, 0x5c, 0xb9, 0x77, 0xc2) #define LINUX_EFI_INITRD_MEDIA_GUID EFI_GUID(0x5568e427, 0x68fc, 0x4f3d, 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68) #define LINUX_EFI_MOK_VARIABLE_TABLE_GUID EFI_GUID(0xc451ed2b, 0x9694, 0x45d3, 0xba, 0xba, 0xed, 0x9f, 0x89, 0x88, 0xa3, 0x89) +#define LINUX_EFI_COCO_SECRET_AREA_GUID EFI_GUID(0x940ed1e9, 0xd3da, 0x408b, 0xb3, 0x07, 0xe3, 0x2d, 0x25, 0x4a, 0x65, 0x16) /* OEM GUIDs */ #define DELLEMC_EFI_RCI2_TABLE_GUID EFI_GUID(0x2d9f28a2, 0xa886, 0x456a, 0x97, 0xa8, 0xf1, 0x1e, 0xf2, 0x4f, 0xf4, 0x55) @@ -1282,4 +1283,9 @@ static inline struct efi_mokvar_table_entry *efi_mokvar_entry_find( } #endif +struct linux_efi_coco_secret_area { + u32 size; + u8 area[]; +}; + #endif /* _LINUX_EFI_H */