From patchwork Thu Apr 15 19:46:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris von Recklinghausen X-Patchwork-Id: 423003 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 B03D0C433ED for ; Thu, 15 Apr 2021 19:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B5DF61153 for ; Thu, 15 Apr 2021 19:46:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234969AbhDOTrV (ORCPT ); Thu, 15 Apr 2021 15:47:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:24355 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234958AbhDOTrU (ORCPT ); Thu, 15 Apr 2021 15:47:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618516017; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc; bh=NFvD14E/O2xfcZkQUJKPm+kNaCcXcWDI9yc+KeoaA1o=; b=I0YYaHvJFvWTa46y5TltxkQr8iydKOKBs/MxaNgqIFdBf6yhhIgfv8WKWaV6XgRCnq5ozZ N5XP0r+dePvIy9406iXJUSHcLx5u93phLiGXR78zyvP5wzRtjr7uE/OyZ2GNVKVevxu8nA cddu4G+C0XxrGW0dgi2z6QfTLBqRBhI= 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-333-4ljUzWjkN4CmeKKcVUJFMw-1; Thu, 15 Apr 2021 15:46:53 -0400 X-MC-Unique: 4ljUzWjkN4CmeKKcVUJFMw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A3962501FE; Thu, 15 Apr 2021 19:46:51 +0000 (UTC) Received: from crecklin.bos.com (unknown [10.10.115.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6F26310074E1; Thu, 15 Apr 2021 19:46:47 +0000 (UTC) From: Chris von Recklinghausen To: ebiggers@kernel.org, ardb@kernel.org, simo@redhat.com, rafael@kernel.org, decui@microsoft.com, linux-pm@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v8 1/1] use crc32 instead of md5 for hibernation e820 integrity check Date: Thu, 15 Apr 2021 15:46:46 -0400 Message-Id: <20210415194646.13387-1-crecklin@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hibernation fails on a system in fips mode because md5 is used for the e820 integrity check and is not available. Use crc32 instead. This patch changes the integrity check algorithm from md5 to crc32. The check is intended to detect whether the E820 memory map provided by the firmware after cold boot unexpectedly differs from the one that was in use when the hibernation image was created. In this case, the hibernation image cannot be restored, as it may cover memory regions that are no longer available to the OS. A non-cryptographic checksum such as CRC-32 is sufficient to detect such inadvertent deviations. Fixes: 62a03defeabd ("PM / hibernate: Verify the consistent of e820 memory map by md5 digest") Signed-off-by: Chris von Recklinghausen --- v1 -> v2 bump up RESTORE_MAGIC v2 -> v3 move embelishment from cover letter to commit comments (no code change) v3 -> v4 add note to comments that md5 isn't used for encryption here. v4 -> v5 reword comment per Simo's suggestion v5 -> v6 use wording from Eric Biggers, use crc32_le instead of crc32 from crypto framework (crc32_le is in the core API and removes need for #defines) v6 -> v7 reword with input from Eric/Ard/Simo, code changed per Eric's feedback v7 -> v8 More feedback per Eric - change 'Suspend' to 'Hibernation' in commit comments, rename e820_digest to e820_checksum and change it to an unsigned long. rename get_e820_md5 to compute_e820_crc32 and have it return the checksum value instead of writing it into a user supplied buffer, get rid of hibernation_e820_save in favor of calling compute_e820_crc32 directly, likewise, get rid of hibernation_e820_mismatch in favor of comparing e820_checksum to the return value of compute_e820_crc32() arch/x86/power/hibernate.c | 87 ++++++-------------------------------- 1 file changed, 12 insertions(+), 75 deletions(-) diff --git a/arch/x86/power/hibernate.c b/arch/x86/power/hibernate.c index cd3914fc9f3d..b358acdc66f4 100644 --- a/arch/x86/power/hibernate.c +++ b/arch/x86/power/hibernate.c @@ -13,8 +13,8 @@ #include #include #include - -#include +#include +#include #include #include @@ -54,95 +54,31 @@ int pfn_is_nosave(unsigned long pfn) return pfn >= nosave_begin_pfn && pfn < nosave_end_pfn; } - -#define MD5_DIGEST_SIZE 16 - struct restore_data_record { unsigned long jump_address; unsigned long jump_address_phys; unsigned long cr3; unsigned long magic; - u8 e820_digest[MD5_DIGEST_SIZE]; + unsigned long e820_checksum; }; -#if IS_BUILTIN(CONFIG_CRYPTO_MD5) /** - * get_e820_md5 - calculate md5 according to given e820 table + * compute_e820_crc32 - calculate md5 according to given e820 table * * @table: the e820 table to be calculated - * @buf: the md5 result to be stored to */ -static int get_e820_md5(struct e820_table *table, void *buf) +static inline u32 compute_e820_crc32(struct e820_table *table) { - struct crypto_shash *tfm; - struct shash_desc *desc; - int size; - int ret = 0; - - tfm = crypto_alloc_shash("md5", 0, 0); - if (IS_ERR(tfm)) - return -ENOMEM; - - desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), - GFP_KERNEL); - if (!desc) { - ret = -ENOMEM; - goto free_tfm; - } - - desc->tfm = tfm; - - size = offsetof(struct e820_table, entries) + + int size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries; - if (crypto_shash_digest(desc, (u8 *)table, size, buf)) - ret = -EINVAL; - - kfree_sensitive(desc); - -free_tfm: - crypto_free_shash(tfm); - return ret; -} - -static int hibernation_e820_save(void *buf) -{ - return get_e820_md5(e820_table_firmware, buf); + return ~crc32_le(~0, (unsigned char const *)table, size); } -static bool hibernation_e820_mismatch(void *buf) -{ - int ret; - u8 result[MD5_DIGEST_SIZE]; - - memset(result, 0, MD5_DIGEST_SIZE); - /* If there is no digest in suspend kernel, let it go. */ - if (!memcmp(result, buf, MD5_DIGEST_SIZE)) - return false; - - ret = get_e820_md5(e820_table_firmware, result); - if (ret) - return true; - - return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false; -} -#else -static int hibernation_e820_save(void *buf) -{ - return 0; -} - -static bool hibernation_e820_mismatch(void *buf) -{ - /* If md5 is not builtin for restore kernel, let it go. */ - return false; -} -#endif - #ifdef CONFIG_X86_64 -#define RESTORE_MAGIC 0x23456789ABCDEF01UL +#define RESTORE_MAGIC 0x23456789ABCDEF02UL #else -#define RESTORE_MAGIC 0x12345678UL +#define RESTORE_MAGIC 0x12345679UL #endif /** @@ -179,7 +115,8 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size) */ rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK; - return hibernation_e820_save(rdr->e820_digest); + rdr->e820_checksum = compute_e820_crc32(e820_table_firmware); + return 0; } /** @@ -200,7 +137,7 @@ int arch_hibernation_header_restore(void *addr) jump_address_phys = rdr->jump_address_phys; restore_cr3 = rdr->cr3; - if (hibernation_e820_mismatch(rdr->e820_digest)) { + if (rdr->e820_checksum != compute_e820_crc32(e820_table_firmware)) { pr_crit("Hibernate inconsistent memory map detected!\n"); return -ENODEV; }