From patchwork Wed Feb 15 14:51:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alexandre Ghiti X-Patchwork-Id: 654824 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29B51C636D4 for ; Wed, 15 Feb 2023 14:54:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229740AbjBOOyW (ORCPT ); Wed, 15 Feb 2023 09:54:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229574AbjBOOyV (ORCPT ); Wed, 15 Feb 2023 09:54:21 -0500 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12C9F2884E for ; Wed, 15 Feb 2023 06:54:20 -0800 (PST) Received: by mail-wm1-x334.google.com with SMTP id hg24-20020a05600c539800b003e1f5f2a29cso1755460wmb.4 for ; Wed, 15 Feb 2023 06:54:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=o4BvO75ZXrS10LcJgsz5zZo07cuKH8B95qcklsNq3N4=; b=eJwhJ0KloQW4mUrbp/N3CD+WQpxcec1WXR77m6jHwd2ZBGUgvgl59M61JDT9YepATU GcEXqyFBrXjKS40imQJoOKr008H1gWwgRIDNGNNLxMJr6Be/ZBn8lMJjqGXSL5vBz1oc 4UxXpwDr5Aw3SHaLbU2+tEqHHkpSpIXrlyccNsgfJZj6JTRIgFX+oUH73RUl8pk754gt HUIm85UIWorCz5T435tLoiMQWdCWQJSK0vJtREOnuBnhF7B6plkQT56+vEtDlDoBWZaw zszx7g1tyrR10lOVOMhlWI8NNdUcTzF54Si7ByUYk+Ff+n5JtKXZ+nQ4q0DouiKsN1dB ju2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=o4BvO75ZXrS10LcJgsz5zZo07cuKH8B95qcklsNq3N4=; b=vgisVaVn5G8elehajj+1ezF4iLyt2UoCe2u8xrpkrUVoni/KXe+ypQYIzLk9dxwUoJ 6H37gRkJAL7L5tDDjStzFmgeHGp+aYYDNpENQ5bIL0+nB5PCvjy/0b/pFIoIhG5SuXmy YCm62DNzEeNjiOhqw+Yo6lzYO7D1CY3IdO5xtdQ7BlCCE75b6V2s6MttHVUo3I8VdqbQ 4C1A4HMkwMWPWRWBVlQcTeaXJM6DJGmWHe2xqDcgOucGDX6OhVEC2gc59ujuxkxIrLCE kdC3zNlJDSi0ezP9ccvmd5KTpY54orIJCV96GEfVAm6s2TgThqpjJam7f4D2cCgpXHwS 0v5w== X-Gm-Message-State: AO0yUKVsCwBvisK2xNc86rL7UNgskxt29Ayt27LbrRhh8URVsdh/RF/t RsDM1ExCaWa8Lws75MphlM9NaA== X-Google-Smtp-Source: AK7set+z1EuF/qTEsW13BueUE8joVeOlGJPKhW0X4Yacc2kbVno1G0GuXcjMOyleMwbiyg2+WUkCcg== X-Received: by 2002:a05:600c:5128:b0:3de:e8c5:d833 with SMTP id o40-20020a05600c512800b003dee8c5d833mr2690072wms.22.1676472858522; Wed, 15 Feb 2023 06:54:18 -0800 (PST) Received: from alex-rivos.home (lfbn-lyo-1-450-160.w2-7.abo.wanadoo.fr. [2.7.42.160]) by smtp.gmail.com with ESMTPSA id i29-20020a1c541d000000b003dc4fd6e624sm2358568wmb.19.2023.02.15.06.54.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Feb 2023 06:54:18 -0800 (PST) From: Alexandre Ghiti To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Ard Biesheuvel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org Cc: Alexandre Ghiti Subject: [PATCH 3/4] arm64: libstub: Move KASLR handling functions to efi-stub-helper.c Date: Wed, 15 Feb 2023 15:51:12 +0100 Message-Id: <20230215145113.465558-4-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230215145113.465558-1-alexghiti@rivosinc.com> References: <20230215145113.465558-1-alexghiti@rivosinc.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org This prepares for riscv to use the same functions to handle the pĥysical kernel move when KASLR is enabled. Signed-off-by: Alexandre Ghiti --- drivers/firmware/efi/libstub/arm64-stub.c | 110 +------------ .../firmware/efi/libstub/efi-stub-helper.c | 147 ++++++++++++++++++ drivers/firmware/efi/libstub/efistub.h | 8 + 3 files changed, 162 insertions(+), 103 deletions(-) diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 7327b98d8e3f..86ea9bfa6513 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -14,42 +14,6 @@ #include "efistub.h" -/* - * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail - * to provide space, and fail to zero it). Check for this condition by double - * checking that the first and the last byte of the image are covered by the - * same EFI memory map entry. - */ -static bool check_image_region(u64 base, u64 size) -{ - struct efi_boot_memmap *map; - efi_status_t status; - bool ret = false; - int map_offset; - - status = efi_get_memory_map(&map, false); - if (status != EFI_SUCCESS) - return false; - - for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { - efi_memory_desc_t *md = (void *)map->map + map_offset; - u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; - - /* - * Find the region that covers base, and return whether - * it covers base+size bytes. - */ - if (base >= md->phys_addr && base < end) { - ret = (base + size) <= end; - break; - } - } - - efi_bs_call(free_pool, map); - - return ret; -} - efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, @@ -59,31 +23,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, { efi_status_t status; unsigned long kernel_size, kernel_memsize = 0; - u32 phys_seed = 0; - u64 min_kimg_align = efi_get_kimg_min_align(); - - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { - efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; - void *p; - - if (efi_nokaslr) { - efi_info("KASLR disabled on kernel command line\n"); - } else if (efi_bs_call(handle_protocol, image_handle, - &li_fixed_proto, &p) == EFI_SUCCESS) { - efi_info("Image placement fixed by loader\n"); - } else { - status = efi_get_random_bytes(sizeof(phys_seed), - (u8 *)&phys_seed); - if (status == EFI_NOT_FOUND) { - efi_info("EFI_RNG_PROTOCOL unavailable\n"); - efi_nokaslr = true; - } else if (status != EFI_SUCCESS) { - efi_err("efi_get_random_bytes() failed (0x%lx)\n", - status); - efi_nokaslr = true; - } - } - } if (image->image_base != _text) efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n"); @@ -95,50 +34,15 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, kernel_size = _edata - _text; kernel_memsize = kernel_size + (_end - _edata); *reserve_size = kernel_memsize; + *image_addr = (unsigned long)_text; - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { - /* - * If KASLR is enabled, and we have some randomness available, - * locate the kernel at a randomized offset in physical memory. - */ - status = efi_random_alloc(*reserve_size, min_kimg_align, - reserve_addr, phys_seed, - EFI_LOADER_CODE); - if (status != EFI_SUCCESS) - efi_warn("efi_random_alloc() failed: 0x%lx\n", status); - } else { - status = EFI_OUT_OF_RESOURCES; - } - - if (status != EFI_SUCCESS) { - if (!check_image_region((u64)_text, kernel_memsize)) { - efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); - } else if (IS_ALIGNED((u64)_text, min_kimg_align) && - (u64)_end < EFI_ALLOC_LIMIT) { - /* - * Just execute from wherever we were loaded by the - * UEFI PE/COFF loader if the placement is suitable. - */ - *image_addr = (u64)_text; - *reserve_size = 0; - goto clean_image_to_poc; - } - - status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, - ULONG_MAX, min_kimg_align, - EFI_LOADER_CODE); - - if (status != EFI_SUCCESS) { - efi_err("Failed to relocate kernel\n"); - *reserve_size = 0; - return status; - } - } - - *image_addr = *reserve_addr; - memcpy((void *)*image_addr, _text, kernel_size); + status = efi_kaslr_relocate_kernel(image_addr, + reserve_addr, reserve_size, + kernel_size, kernel_memsize, + efi_kaslr_get_phys_seed(image_handle)); + if (status != EFI_SUCCESS) + return status; -clean_image_to_poc: /* * Clean the copied Image to the PoC, and ensure it is not shadowed by * stale icache entries from before relocation. diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index f5a4bdacac64..ebf72beee4f5 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -651,3 +651,150 @@ efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key) return status; } + +/** + * efi_kaslr_get_phys_seed() - Get random seed for physical kernel KASLR + * @image_handle: Handle to the image + * + * If KASLR is not disabled, obtain a random seed using EFI_RNG_PROTOCOL + * that will be used to move the kernel physical mapping. + * + * Return: the random seed + */ +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle) +{ + efi_status_t status; + u32 phys_seed; + efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; + void *p; + + if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) + return 0; + + if (efi_nokaslr) { + efi_info("KASLR disabled on kernel command line\n"); + } else if (efi_bs_call(handle_protocol, image_handle, + &li_fixed_proto, &p) == EFI_SUCCESS) { + efi_info("Image placement fixed by loader\n"); + } else { + status = efi_get_random_bytes(sizeof(phys_seed), + (u8 *)&phys_seed); + if (status == EFI_SUCCESS) + return phys_seed; + else if (status == EFI_NOT_FOUND) { + efi_info("EFI_RNG_PROTOCOL unavailable\n"); + efi_nokaslr = true; + } else if (status != EFI_SUCCESS) { + efi_err("efi_get_random_bytes() failed (0x%lx)\n", + status); + efi_nokaslr = true; + } + } + + return 0; +} + +/* + * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail + * to provide space, and fail to zero it). Check for this condition by double + * checking that the first and the last byte of the image are covered by the + * same EFI memory map entry. + */ +static bool check_image_region(u64 base, u64 size) +{ + struct efi_boot_memmap *map; + efi_status_t status; + bool ret = false; + int map_offset; + + status = efi_get_memory_map(&map, false); + if (status != EFI_SUCCESS) + return false; + + for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { + efi_memory_desc_t *md = (void *)map->map + map_offset; + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; + + /* + * Find the region that covers base, and return whether + * it covers base+size bytes. + */ + if (base >= md->phys_addr && base < end) { + ret = (base + size) <= end; + break; + } + } + + efi_bs_call(free_pool, map); + + return ret; +} + +/** + * efi_kaslr_relocate_kernel() - Relocate the kernel (random if KASLR enabled) + * @image_addr: Pointer to the current kernel location + * @reserve_addr: Pointer to the relocated kernel location + * @reserve_size: Size of the relocated kernel + * @kernel_size: Size of the text + data + * @kernel_memsize: Size of the text + data + bss + * @phys_seed: Random seed used for the relocation + * + * If KASLR is not enabled, this function relocates the kernel to a fixed + * address (or leave it as its current location). If KASLR is enabled, the + * kernel physical location is randomized using the seed in parameter. + * + * Return: status code, EFI_SUCCESS if relocation is successful + */ +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, + unsigned long *reserve_addr, + unsigned long *reserve_size, + unsigned long kernel_size, + unsigned long kernel_memsize, + u32 phys_seed) +{ + efi_status_t status; + u64 min_kimg_align = efi_get_kimg_min_align(); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { + /* + * If KASLR is enabled, and we have some randomness available, + * locate the kernel at a randomized offset in physical memory. + */ + status = efi_random_alloc(*reserve_size, min_kimg_align, + reserve_addr, phys_seed, + EFI_LOADER_CODE); + if (status != EFI_SUCCESS) + efi_warn("efi_random_alloc() failed: 0x%lx\n", status); + } else { + status = EFI_OUT_OF_RESOURCES; + } + + if (status != EFI_SUCCESS) { + if (!check_image_region(*image_addr, kernel_memsize)) { + efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); + } else if (IS_ALIGNED(*image_addr, min_kimg_align) && + (u64)_end < EFI_ALLOC_LIMIT) { + /* + * Just execute from wherever we were loaded by the + * UEFI PE/COFF loader if the placement is suitable. + */ + *reserve_size = 0; + return EFI_SUCCESS; + } + + status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, + ULONG_MAX, min_kimg_align, + EFI_LOADER_CODE); + + if (status != EFI_SUCCESS) { + efi_err("Failed to relocate kernel\n"); + *reserve_size = 0; + return status; + } + } + + memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size); + *image_addr = *reserve_addr; + + return status; +} diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 5b8f2c411ed8..747f33763df0 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -1076,4 +1076,12 @@ struct efi_smbios_type1_record { const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize); +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, + unsigned long *reserve_addr, + unsigned long *reserve_size, + unsigned long kernel_size, + unsigned long kernel_memsize, + u32 phys_seed); +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle); + #endif