From patchwork Wed Jan 15 16:35:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 208272 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04702C32771 for ; Wed, 15 Jan 2020 16:36:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BA00A2465A for ; Wed, 15 Jan 2020 16:36:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CSjTlGm4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729092AbgAOQgS (ORCPT ); Wed, 15 Jan 2020 11:36:18 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:42405 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729074AbgAOQgS (ORCPT ); Wed, 15 Jan 2020 11:36:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579106176; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lb0NDxMEx0ddgTbHUh0qQbJhrjsgTsDPRcVNGdh2q24=; b=CSjTlGm4QCRPHvWkei3DbeNI0HL775jk1H2iTd32oJYwZm03snmcTyR3rnojBn9nlNLiba Qh9sw01fk+QglL++r3MCCaI5oXUyZNQV3jgiMDCJqqYM0xQySTojpX2A3LMk+4NKid+nvd aXihJn/IEwtmDCysSUNEIl2nd/eIsaE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-189-qaQDJskDPCOS_wPla5GI2g-1; Wed, 15 Jan 2020 11:36:15 -0500 X-MC-Unique: qaQDJskDPCOS_wPla5GI2g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 51C88100550E; Wed, 15 Jan 2020 16:36:12 +0000 (UTC) Received: from shalem.localdomain.com (ovpn-116-188.ams2.redhat.com [10.36.116.188]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6318C5DA76; Wed, 15 Jan 2020 16:36:08 +0000 (UTC) From: Hans de Goede To: Ard Biesheuvel , Darren Hart , Andy Shevchenko , Luis Chamberlain , Greg Kroah-Hartman , "Rafael J . Wysocki" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Jonathan Corbet , Dmitry Torokhov Cc: Hans de Goede , Peter Jones , Dave Olsthoorn , x86@kernel.org, platform-driver-x86@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-input@vger.kernel.org, Ard Biesheuvel Subject: [PATCH v12 02/10] efi: Add embedded peripheral firmware support Date: Wed, 15 Jan 2020 17:35:46 +0100 Message-Id: <20200115163554.101315-3-hdegoede@redhat.com> In-Reply-To: <20200115163554.101315-1-hdegoede@redhat.com> References: <20200115163554.101315-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Just like with PCI options ROMs, which we save in the setup_efi_pci* functions from arch/x86/boot/compressed/eboot.c, the EFI code / ROM itself sometimes may contain data which is useful/necessary for peripheral drivers to have access to. Specifically the EFI code may contain an embedded copy of firmware which needs to be (re)loaded into the peripheral. Normally such firmware would be part of linux-firmware, but in some cases this is not feasible, for 2 reasons: 1) The firmware is customized for a specific use-case of the chipset / use with a specific hardware model, so we cannot have a single firmware file for the chipset. E.g. touchscreen controller firmwares are compiled specifically for the hardware model they are used with, as they are calibrated for a specific model digitizer. 2) Despite repeated attempts we have failed to get permission to redistribute the firmware. This is especially a problem with customized firmwares, these get created by the chip vendor for a specific ODM and the copyright may partially belong with the ODM, so the chip vendor cannot give a blanket permission to distribute these. This commit adds support for finding peripheral firmware embedded in the EFI code and makes the found firmware available through the new efi_get_embedded_fw() function. Support for loading these firmwares through the standard firmware loading mechanism is added in a follow-up commit in this patch-series. Note we check the EFI_BOOT_SERVICES_CODE for embedded firmware near the end of start_kernel(), just before calling rest_init(), this is on purpose because the typical EFI_BOOT_SERVICES_CODE memory-segment is too large for early_memremap(), so the check must be done after mm_init(). This relies on EFI_BOOT_SERVICES_CODE not being free-ed until efi_free_boot_services() is called, which means that this will only work on x86 for now. Reported-by: Dave Olsthoorn Suggested-by: Peter Jones Acked-by: Ard Biesheuvel Signed-off-by: Hans de Goede --- Changes in v12: - Use memcmp instead of type-punned pointer casting to compare the prefix - Make efi_get_embedded_fw() return a const u8 * pointer to the efi_embedded_fw copy of the firmware instead of doing a vmemdup and and returning that Changes in v9: - At least touchscreen_dmi.c uses the same dmi_table for its own private data and the fw_desc structs, putting the fw_desc struct first in the data driver_data points to so that the dmi_table can be shared with efi_check_for_embedded_firmwares(). But not all entries there have embedded-fw so in some cases the fw_desc is empty (zero-ed out). This can lead to a possible crash because fw_desc->length now is less then 8, so if the segment size is close enough to a multiple of the page_size, then the memcmp to check the prefix my segfault. Crashing the machine. v9 checks for and skips these empty fw_desc entries avoiding this. - Rename found_fw_list to efi_embedded_fw_list and export it for use by lib/test_firmware.c Changes in v8: - Properly deal with the (theoretical?) case of an EFI segment being smaller then the fw we are looking for - Log a warning when efi_get_embedded_fw get called while we did not (yet) check for embedded firmwares Changes in v7: - Split drivers/firmware/efi and drivers/base/firmware_loader changes into 2 patches - Use new, standalone, lib/crypto/sha256.c code Changes in v6: - Rework code to remove casts from if (prefix == mem) comparison - Use SHA256 hashes instead of crc32 sums - Add new READING_FIRMWARE_EFI_EMBEDDED read_file_id and use it - Call security_kernel_read_file(NULL, READING_FIRMWARE_EFI_EMBEDDED) to check if this is allowed before looking at EFI embedded fw - Document why we are not using the UEFI PI Firmware Volume protocol Changes in v5: - Rename the EFI_BOOT_SERVICES flag to EFI_PRESERVE_BS_REGIONS Changes in v4: - Drop note in docs about EFI_FIRMWARE_VOLUME_PROTOCOL, it is not part of UEFI proper, so the EFI maintainers don't want us referring people to it - Use new EFI_BOOT_SERVICES flag - Put the new fw_get_efi_embedded_fw() function in its own fallback_efi.c file which only gets built when EFI_EMBEDDED_FIRMWARE is selected - Define an empty stub for fw_get_efi_embedded_fw() in fallback.h hwen EFI_EMBEDDED_FIRMWARE is not selected, to avoid the need for #ifdefs in firmware_loader/main.c - Properly call security_kernel_post_read_file() on the firmware returned by efi_get_embedded_fw() to make sure that we are allowed to use it Changes in v3: - Fix the docs using "efi-embedded-fw" as property name instead of "efi-embedded-firmware" Changes in v2: - Rebased on driver-core/driver-core-next - Add documentation describing the EFI embedded firmware mechanism to: Documentation/driver-api/firmware/request_firmware.rst - Add a new EFI_EMBEDDED_FIRMWARE Kconfig bool and only build the embedded fw support if this is set. This is an invisible option which should be selected by drivers which need this - Remove the efi_embedded_fw_desc and dmi_system_id-s for known devices from the efi-embedded-fw code, instead drivers using this are expected to export a dmi_system_id array, with each entries' driver_data pointing to a efi_embedded_fw_desc struct and register this with the efi-embedded-fw code - Use kmemdup to make a copy instead of efi_mem_reserve()-ing the firmware, this avoids us messing with the EFI memmap and avoids the need to make changes to efi_mem_desc_lookup() - Make the firmware-loader code only fallback to efi_get_embedded_fw() if the passed in device has the "efi-embedded-firmware" device-property bool set - Skip usermodehelper fallback when "efi-embedded-firmware" device-property is set --- arch/x86/platform/efi/efi.c | 1 + drivers/firmware/efi/Kconfig | 5 + drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/embedded-firmware.c | 147 +++++++++++++++++++++++ include/linux/efi.h | 6 + include/linux/efi_embedded_fw.h | 41 +++++++ 6 files changed, 201 insertions(+) create mode 100644 drivers/firmware/efi/embedded-firmware.c create mode 100644 include/linux/efi_embedded_fw.h diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 51ee2e2a18d6..cc10a925d9e7 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -944,6 +944,7 @@ static void __init __efi_enter_virtual_mode(void) goto err; } + efi_check_for_embedded_firmwares(); efi_free_boot_services(); /* diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index ecc83e2f032c..613828d3f106 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -239,6 +239,11 @@ config EFI_DISABLE_PCI_DMA endmenu +config EFI_EMBEDDED_FIRMWARE + bool + depends on EFI + select CRYPTO_LIB_SHA256 + config UEFI_CPER bool diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index 554d795270d9..256d6121b2b3 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_EFI_TEST) += test/ obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o +obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o fake_map-y += fake_mem.o fake_map-$(CONFIG_X86) += x86_fake_mem.o diff --git a/drivers/firmware/efi/embedded-firmware.c b/drivers/firmware/efi/embedded-firmware.c new file mode 100644 index 000000000000..1bc9cdae2eed --- /dev/null +++ b/drivers/firmware/efi/embedded-firmware.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for extracting embedded firmware for peripherals from EFI code, + * + * Copyright (c) 2018 Hans de Goede + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +/* Exported for use by lib/test_firmware.c only */ +LIST_HEAD(efi_embedded_fw_list); +EXPORT_SYMBOL_GPL(efi_embedded_fw_list); + +static bool checked_for_fw; + +static const struct dmi_system_id * const embedded_fw_table[] = { + NULL +}; + +/* + * Note the efi_check_for_embedded_firmwares() code currently makes the + * following 2 assumptions. This may needs to be revisited if embedded firmware + * is found where this is not true: + * 1) The firmware is only found in EFI_BOOT_SERVICES_CODE memory segments + * 2) The firmware always starts at an offset which is a multiple of 8 bytes + */ +static int __init efi_check_md_for_embedded_firmware( + efi_memory_desc_t *md, const struct efi_embedded_fw_desc *desc) +{ + struct sha256_state sctx; + struct efi_embedded_fw *fw; + u8 sha256[32]; + u64 i, size; + u8 *map; + + size = md->num_pages << EFI_PAGE_SHIFT; + map = memremap(md->phys_addr, size, MEMREMAP_WB); + if (!map) { + pr_err("Error mapping EFI mem at %#llx\n", md->phys_addr); + return -ENOMEM; + } + + for (i = 0; (i + desc->length) <= size; i += 8) { + if (memcmp(map + i, desc->prefix, EFI_EMBEDDED_FW_PREFIX_LEN)) + continue; + + sha256_init(&sctx); + sha256_update(&sctx, map + i, desc->length); + sha256_final(&sctx, sha256); + if (memcmp(sha256, desc->sha256, 32) == 0) + break; + } + if ((i + desc->length) > size) { + memunmap(map); + return -ENOENT; + } + + pr_info("Found EFI embedded fw '%s'\n", desc->name); + + fw = kmalloc(sizeof(*fw), GFP_KERNEL); + if (!fw) { + memunmap(map); + return -ENOMEM; + } + + fw->data = kmemdup(map + i, desc->length, GFP_KERNEL); + memunmap(map); + if (!fw->data) { + kfree(fw); + return -ENOMEM; + } + + fw->name = desc->name; + fw->length = desc->length; + list_add(&fw->list, &efi_embedded_fw_list); + + return 0; +} + +void __init efi_check_for_embedded_firmwares(void) +{ + const struct efi_embedded_fw_desc *fw_desc; + const struct dmi_system_id *dmi_id; + efi_memory_desc_t *md; + int i, r; + + for (i = 0; embedded_fw_table[i]; i++) { + dmi_id = dmi_first_match(embedded_fw_table[i]); + if (!dmi_id) + continue; + + fw_desc = dmi_id->driver_data; + + /* + * In some drivers the struct driver_data contains may contain + * other driver specific data after the fw_desc struct; and + * the fw_desc struct itself may be empty, skip these. + */ + if (!fw_desc->name) + continue; + + for_each_efi_memory_desc(md) { + if (md->type != EFI_BOOT_SERVICES_CODE) + continue; + + r = efi_check_md_for_embedded_firmware(md, fw_desc); + if (r == 0) + break; + } + } + + checked_for_fw = true; +} + +int efi_get_embedded_fw(const char *name, const u8 **data, size_t *size) +{ + struct efi_embedded_fw *iter, *fw = NULL; + + if (!checked_for_fw) { + pr_warn("Warning %s called while we did not check for embedded fw\n", + __func__); + return -ENOENT; + } + + list_for_each_entry(iter, &efi_embedded_fw_list, list) { + if (strcmp(name, iter->name) == 0) { + fw = iter; + break; + } + } + + if (!fw) + return -ENOENT; + + *data = fw->data; + *size = fw->length; + + return 0; +} +EXPORT_SYMBOL_GPL(efi_get_embedded_fw); diff --git a/include/linux/efi.h b/include/linux/efi.h index a6e1a2d8511e..23392b88bcc0 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1554,6 +1554,12 @@ static inline void efi_enable_reset_attack_mitigation(void) { } #endif +#ifdef CONFIG_EFI_EMBEDDED_FIRMWARE +void efi_check_for_embedded_firmwares(void); +#else +static inline void efi_check_for_embedded_firmwares(void) { } +#endif + efi_status_t efi_random_get_seed(void); void efi_retrieve_tpm2_eventlog(void); diff --git a/include/linux/efi_embedded_fw.h b/include/linux/efi_embedded_fw.h new file mode 100644 index 000000000000..3d066c6370c6 --- /dev/null +++ b/include/linux/efi_embedded_fw.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_EFI_EMBEDDED_FW_H +#define _LINUX_EFI_EMBEDDED_FW_H + +#include +#include + +#define EFI_EMBEDDED_FW_PREFIX_LEN 8 + +/* + * This struct and efi_embedded_fw_list are private to the efi-embedded fw + * implementation they are in this header for use by lib/test_firmware.c only! + */ +struct efi_embedded_fw { + struct list_head list; + const char *name; + const u8 *data; + size_t length; +}; + +extern struct list_head efi_embedded_fw_list; + +/** + * struct efi_embedded_fw_desc - This struct is used by the EFI embedded-fw + * code to search for embedded firmwares. + * + * @name: Name to register the firmware with if found + * @prefix: First 8 bytes of the firmware + * @length: Length of the firmware in bytes including prefix + * @sha256: SHA256 of the firmware + */ +struct efi_embedded_fw_desc { + const char *name; + u8 prefix[EFI_EMBEDDED_FW_PREFIX_LEN]; + u32 length; + u8 sha256[32]; +}; + +int efi_get_embedded_fw(const char *name, const u8 **dat, size_t *sz); + +#endif