From patchwork Fri Mar 12 17:12:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 398873 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 90963C43381 for ; Fri, 12 Mar 2021 17:13:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6255964FB5 for ; Fri, 12 Mar 2021 17:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232478AbhCLRNR (ORCPT ); Fri, 12 Mar 2021 12:13:17 -0500 Received: from smtp-42a9.mail.infomaniak.ch ([84.16.66.169]:54615 "EHLO smtp-42a9.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232311AbhCLRNM (ORCPT ); Fri, 12 Mar 2021 12:13:12 -0500 Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DxspH0687zMqqBB; Fri, 12 Mar 2021 18:13:11 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4DxspG4qrkzlh8TC; Fri, 12 Mar 2021 18:13:10 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse , Jarkko Sakkinen Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Eric Snowberg , Herbert Xu , James Morris , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , Tyler Hicks , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v7 1/5] tools/certs: Add print-cert-tbs-hash.sh Date: Fri, 12 Mar 2021 18:12:28 +0100 Message-Id: <20210312171232.2681989-2-mic@digikod.net> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210312171232.2681989-1-mic@digikod.net> References: <20210312171232.2681989-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org From: Mickaël Salaün Add a new helper print-cert-tbs-hash.sh to generate a TBSCertificate hash from a given certificate. This is useful to generate a blacklist key description used to forbid loading a specific certificate in a keyring, or to invalidate a certificate provided by a PKCS#7 file. This kind of hash formatting is required to populate the file pointed out by CONFIG_SYSTEM_BLACKLIST_HASH_LIST, but only the kernel code was available to understand how to effectively create such hash. Cc: David Howells Cc: David Woodhouse Cc: Eric Snowberg Signed-off-by: Mickaël Salaün Reviewed-by: Jarkko Sakkinen Link: https://lore.kernel.org/r/20210312171232.2681989-2-mic@digikod.net Tested-by: Eric Snowberg --- Changes since v5: * Add Reviewed-by Jarkko. Changes since v3: * Explain in the commit message that this kind of formating is not new but it wasn't documented. Changes since v1: * Fix typo. * Use "if" block instead of "||" . --- MAINTAINERS | 1 + tools/certs/print-cert-tbs-hash.sh | 91 ++++++++++++++++++++++++++++++ 2 files changed, 92 insertions(+) create mode 100755 tools/certs/print-cert-tbs-hash.sh diff --git a/MAINTAINERS b/MAINTAINERS index 00836f6452f0..773a362e807f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4120,6 +4120,7 @@ F: Documentation/admin-guide/module-signing.rst F: certs/ F: scripts/extract-cert.c F: scripts/sign-file.c +F: tools/certs/ CFAG12864B LCD DRIVER M: Miguel Ojeda Sandonis diff --git a/tools/certs/print-cert-tbs-hash.sh b/tools/certs/print-cert-tbs-hash.sh new file mode 100755 index 000000000000..c93df5387ec9 --- /dev/null +++ b/tools/certs/print-cert-tbs-hash.sh @@ -0,0 +1,91 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright © 2020, Microsoft Corporation. All rights reserved. +# +# Author: Mickaël Salaün +# +# Compute and print the To Be Signed (TBS) hash of a certificate. This is used +# as description of keys in the blacklist keyring to identify certificates. +# This output should be redirected, without newline, in a file (hash0.txt) and +# signed to create a PKCS#7 file (hash0.p7s). Both of these files can then be +# loaded in the kernel with. +# +# Exemple on a workstation: +# ./print-cert-tbs-hash.sh certificate-to-invalidate.pem > hash0.txt +# openssl smime -sign -in hash0.txt -inkey builtin-private-key.pem \ +# -signer builtin-certificate.pem -certfile certificate-chain.pem \ +# -noattr -binary -outform DER -out hash0.p7s +# +# Exemple on a managed system: +# keyctl padd blacklist "$(< hash0.txt)" %:.blacklist < hash0.p7s + +set -u -e -o pipefail + +CERT="${1:-}" +BASENAME="$(basename -- "${BASH_SOURCE[0]}")" + +if [ $# -ne 1 ] || [ ! -f "${CERT}" ]; then + echo "usage: ${BASENAME} " >&2 + exit 1 +fi + +# Checks that it is indeed a certificate (PEM or DER encoded) and exclude the +# optional PEM text header. +if ! PEM="$(openssl x509 -inform DER -in "${CERT}" 2>/dev/null || openssl x509 -in "${CERT}")"; then + echo "ERROR: Failed to parse certificate" >&2 + exit 1 +fi + +# TBSCertificate starts at the second entry. +# Cf. https://tools.ietf.org/html/rfc3280#section-4.1 +# +# Exemple of first lines printed by openssl asn1parse: +# 0:d=0 hl=4 l= 763 cons: SEQUENCE +# 4:d=1 hl=4 l= 483 cons: SEQUENCE +# 8:d=2 hl=2 l= 3 cons: cont [ 0 ] +# 10:d=3 hl=2 l= 1 prim: INTEGER :02 +# 13:d=2 hl=2 l= 20 prim: INTEGER :3CEB2CB8818D968AC00EEFE195F0DF9665328B7B +# 35:d=2 hl=2 l= 13 cons: SEQUENCE +# 37:d=3 hl=2 l= 9 prim: OBJECT :sha256WithRSAEncryption +RANGE_AND_DIGEST_RE=' +2s/^\s*\([0-9]\+\):d=\s*[0-9]\+\s\+hl=\s*[0-9]\+\s\+l=\s*\([0-9]\+\)\s\+cons:\s*SEQUENCE\s*$/\1 \2/p; +7s/^\s*[0-9]\+:d=\s*[0-9]\+\s\+hl=\s*[0-9]\+\s\+l=\s*[0-9]\+\s\+prim:\s*OBJECT\s*:\(.*\)$/\1/p; +' + +RANGE_AND_DIGEST=($(echo "${PEM}" | \ + openssl asn1parse -in - | \ + sed -n -e "${RANGE_AND_DIGEST_RE}")) + +if [ "${#RANGE_AND_DIGEST[@]}" != 3 ]; then + echo "ERROR: Failed to parse TBSCertificate." >&2 + exit 1 +fi + +OFFSET="${RANGE_AND_DIGEST[0]}" +END="$(( OFFSET + RANGE_AND_DIGEST[1] ))" +DIGEST="${RANGE_AND_DIGEST[2]}" + +# The signature hash algorithm is used by Linux to blacklist certificates. +# Cf. crypto/asymmetric_keys/x509_cert_parser.c:x509_note_pkey_algo() +DIGEST_MATCH="" +while read -r DIGEST_ITEM; do + if [ -z "${DIGEST_ITEM}" ]; then + break + fi + if echo "${DIGEST}" | grep -qiF "${DIGEST_ITEM}"; then + DIGEST_MATCH="${DIGEST_ITEM}" + break + fi +done < <(openssl list -digest-commands | tr ' ' '\n' | sort -ur) + +if [ -z "${DIGEST_MATCH}" ]; then + echo "ERROR: Unknown digest algorithm: ${DIGEST}" >&2 + exit 1 +fi + +echo "${PEM}" | \ + openssl x509 -in - -outform DER | \ + dd "bs=1" "skip=${OFFSET}" "count=${END}" "status=none" | \ + openssl dgst "-${DIGEST_MATCH}" - | \ + awk '{printf "tbs:" $2}' From patchwork Fri Mar 12 17:12:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 398872 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 F0E59C4332B for ; Fri, 12 Mar 2021 17:14:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C708264FF5 for ; Fri, 12 Mar 2021 17:14:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231928AbhCLRNv (ORCPT ); Fri, 12 Mar 2021 12:13:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231597AbhCLRNS (ORCPT ); Fri, 12 Mar 2021 12:13:18 -0500 Received: from smtp-bc0e.mail.infomaniak.ch (smtp-bc0e.mail.infomaniak.ch [IPv6:2001:1600:4:17::bc0e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52AACC061763 for ; Fri, 12 Mar 2021 09:13:17 -0800 (PST) Received: from smtp-3-0001.mail.infomaniak.ch (unknown [10.4.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DxspM4SqWzMq77Y; Fri, 12 Mar 2021 18:13:15 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4DxspJ0JVgzlh8TT; Fri, 12 Mar 2021 18:13:11 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse , Jarkko Sakkinen Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Eric Snowberg , Herbert Xu , James Morris , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , Tyler Hicks , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v7 2/5] certs: Check that builtin blacklist hashes are valid Date: Fri, 12 Mar 2021 18:12:29 +0100 Message-Id: <20210312171232.2681989-3-mic@digikod.net> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210312171232.2681989-1-mic@digikod.net> References: <20210312171232.2681989-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org From: Mickaël Salaün Add and use a check-blacklist-hashes.awk script to make sure that the builtin blacklist hashes set with CONFIG_SYSTEM_BLACKLIST_HASH_LIST will effectively be taken into account as blacklisted hashes. This is useful to debug invalid hash formats, and it make sure that previous hashes which could have been loaded in the kernel, but silently ignored, are now noticed and deal with by the user at kernel build time. This also prevent stricter blacklist key description checking (provided by following commits) to failed for builtin hashes. Update CONFIG_SYSTEM_BLACKLIST_HASH_LIST help to explain the content of a hash string and how to generate certificate ones. Cc: David Howells Cc: David Woodhouse Cc: Eric Snowberg Cc: Jarkko Sakkinen Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20210312171232.2681989-3-mic@digikod.net Reviewed-by: Jarkko Sakkinen --- Changes since v5: * Rebase on keys-next and fix conflict as previously done by David Howells. * Enable to use a file path relative to the kernel source directory. This align with the handling of CONFIG_SYSTEM_TRUSTED_KEYS, CONFIG_MODULE_SIG_KEY and CONFIG_SYSTEM_REVOCATION_KEYS. Changes since v3: * Improve commit description. * Update CONFIG_SYSTEM_BLACKLIST_HASH_LIST help. * Remove Acked-by Jarkko Sakkinen because of the above changes. Changes since v2: * Add Jarkko's Acked-by. Changes since v1: * Prefix script path with $(scrtree)/ (suggested by David Howells). * Fix hexadecimal number check. --- MAINTAINERS | 1 + certs/.gitignore | 1 + certs/Kconfig | 7 ++++-- certs/Makefile | 17 +++++++++++++- scripts/check-blacklist-hashes.awk | 37 ++++++++++++++++++++++++++++++ 5 files changed, 60 insertions(+), 3 deletions(-) create mode 100755 scripts/check-blacklist-hashes.awk diff --git a/MAINTAINERS b/MAINTAINERS index 773a362e807f..a18fd3d283c6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4118,6 +4118,7 @@ L: keyrings@vger.kernel.org S: Maintained F: Documentation/admin-guide/module-signing.rst F: certs/ +F: scripts/check-blacklist-hashes.awk F: scripts/extract-cert.c F: scripts/sign-file.c F: tools/certs/ diff --git a/certs/.gitignore b/certs/.gitignore index 2a2483990686..42cc2ac24b93 100644 --- a/certs/.gitignore +++ b/certs/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only +blacklist_hashes_checked x509_certificate_list diff --git a/certs/Kconfig b/certs/Kconfig index ab88d2a7f3c7..cf3740c1b22b 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -80,8 +80,11 @@ config SYSTEM_BLACKLIST_HASH_LIST help If set, this option should be the filename of a list of hashes in the form "", "", ... . This will be included into a C - wrapper to incorporate the list into the kernel. Each should - be a string of hex digits. + wrapper to incorporate the list into the kernel. Each must be a + string starting with a prefix ("tbs" or "bin"), then a colon (":"), and + finally an even number of hexadecimal lowercase characters (up to 128). + Certificate hashes can be generated with + tools/certs/print-cert-tbs-hash.sh . config SYSTEM_REVOCATION_LIST bool "Provide system-wide ring of revocation certificates" diff --git a/certs/Makefile b/certs/Makefile index b6db52ebf0be..61e82b8eacd2 100644 --- a/certs/Makefile +++ b/certs/Makefile @@ -7,7 +7,22 @@ obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o c obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o common.o obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"") + +quiet_cmd_check_blacklist_hashes = CHECK $(patsubst "%",%,$(2)) + cmd_check_blacklist_hashes = $(AWK) -f $(srctree)/scripts/check-blacklist-hashes.awk $(2); touch $@ + +$(eval $(call config_filename,SYSTEM_BLACKLIST_HASH_LIST)) + +$(obj)/blacklist_hashes.o: $(obj)/blacklist_hashes_checked + +CFLAGS_blacklist_hashes.o += -I$(srctree) + +targets += blacklist_hashes_checked +$(obj)/blacklist_hashes_checked: $(SYSTEM_BLACKLIST_HASH_LIST_SRCPREFIX)$(SYSTEM_BLACKLIST_HASH_LIST_FILENAME) scripts/check-blacklist-hashes.awk FORCE + $(call if_changed,check_blacklist_hashes,$(SYSTEM_BLACKLIST_HASH_LIST_SRCPREFIX)$(CONFIG_SYSTEM_BLACKLIST_HASH_LIST)) + obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o + else obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o endif @@ -30,7 +45,7 @@ $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREF $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS)) endif # CONFIG_SYSTEM_TRUSTED_KEYRING -clean-files := x509_certificate_list .x509.list x509_revocation_list +clean-files := x509_certificate_list .x509.list x509_revocation_list blacklist_hashes_checked ifeq ($(CONFIG_MODULE_SIG),y) ############################################################################### diff --git a/scripts/check-blacklist-hashes.awk b/scripts/check-blacklist-hashes.awk new file mode 100755 index 000000000000..107c1d3204d4 --- /dev/null +++ b/scripts/check-blacklist-hashes.awk @@ -0,0 +1,37 @@ +#!/usr/bin/awk -f +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright © 2020, Microsoft Corporation. All rights reserved. +# +# Author: Mickaël Salaün +# +# Check that a CONFIG_SYSTEM_BLACKLIST_HASH_LIST file contains a valid array of +# hash strings. Such string must start with a prefix ("tbs" or "bin"), then a +# colon (":"), and finally an even number of hexadecimal lowercase characters +# (up to 128). + +BEGIN { + RS = "," +} +{ + if (!match($0, "^[ \t\n\r]*\"([^\"]*)\"[ \t\n\r]*$", part1)) { + print "Not a string (item " NR "):", $0; + exit 1; + } + if (!match(part1[1], "^(tbs|bin):(.*)$", part2)) { + print "Unknown prefix (item " NR "):", part1[1]; + exit 1; + } + if (!match(part2[2], "^([0-9a-f]+)$", part3)) { + print "Not a lowercase hexadecimal string (item " NR "):", part2[2]; + exit 1; + } + if (length(part3[1]) > 128) { + print "Hash string too long (item " NR "):", part3[1]; + exit 1; + } + if (length(part3[1]) % 2 == 1) { + print "Not an even number of hexadecimal characters (item " NR "):", part3[1]; + exit 1; + } +} From patchwork Fri Mar 12 17:12:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 398871 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 C2D3CC43619 for ; Fri, 12 Mar 2021 17:14:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FF7C65032 for ; Fri, 12 Mar 2021 17:14:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232398AbhCLRNx (ORCPT ); Fri, 12 Mar 2021 12:13:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232740AbhCLRNX (ORCPT ); Fri, 12 Mar 2021 12:13:23 -0500 Received: from smtp-1908.mail.infomaniak.ch (smtp-1908.mail.infomaniak.ch [IPv6:2001:1600:4:17::1908]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D1CBC061574 for ; Fri, 12 Mar 2021 09:13:23 -0800 (PST) Received: from smtp-3-0001.mail.infomaniak.ch (unknown [10.4.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DxspQ11zgzMq5Vl; Fri, 12 Mar 2021 18:13:18 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4DxspP5lvtzlh8TB; Fri, 12 Mar 2021 18:13:17 +0100 (CET) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: David Howells , David Woodhouse , Jarkko Sakkinen Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , Eric Snowberg , Herbert Xu , James Morris , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , "Serge E . Hallyn" , Tyler Hicks , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v7 4/5] certs: Factor out the blacklist hash creation Date: Fri, 12 Mar 2021 18:12:31 +0100 Message-Id: <20210312171232.2681989-5-mic@digikod.net> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210312171232.2681989-1-mic@digikod.net> References: <20210312171232.2681989-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org From: Mickaël Salaün Factor out the blacklist hash creation with the get_raw_hash() helper. This also centralize the "tbs" and "bin" prefixes and make them private, which help to manage them consistently. Cc: David Howells Cc: David S. Miller Cc: David Woodhouse Cc: Eric Snowberg Cc: Herbert Xu Cc: Jarkko Sakkinen Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20210312171232.2681989-5-mic@digikod.net Reviewed-by: Jarkko Sakkinen --- Changes since v6: * Rebase on keys-cve-2020-26541-v3: commit ebd9c2ae369a ("integrity: Load mokx variables into the blacklist keyring"). Changes since v5: * Rebase on keys-next and fix conflict as previously done by David Howells. * Fix missing part to effectively handle UEFI DBX blacklisting. * Remove Jarkko's Acked-by because of the above changes. Changes since v2: * Add Jarkko's Acked-by. --- certs/blacklist.c | 76 ++++++++++++++----- crypto/asymmetric_keys/x509_public_key.c | 3 +- include/keys/system_keyring.h | 14 +++- .../platform_certs/keyring_handler.c | 26 +------ 4 files changed, 73 insertions(+), 46 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 97a35cf9a62c..b254c87ceb3a 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -109,11 +109,43 @@ static struct key_type key_type_blacklist = { .describe = blacklist_describe, }; +static char *get_raw_hash(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type) +{ + size_t type_len; + const char *type_prefix; + char *buffer, *p; + + switch (hash_type) { + case BLACKLIST_HASH_X509_TBS: + type_len = sizeof(tbs_prefix) - 1; + type_prefix = tbs_prefix; + break; + case BLACKLIST_HASH_BINARY: + type_len = sizeof(bin_prefix) - 1; + type_prefix = bin_prefix; + break; + default: + WARN_ON_ONCE(1); + return ERR_PTR(-EINVAL); + } + buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + p = memcpy(buffer, type_prefix, type_len); + p += type_len; + *p++ = ':'; + bin2hex(p, hash, hash_len); + p += hash_len * 2; + *p = '\0'; + return buffer; +} + /** - * mark_hash_blacklisted - Add a hash to the system blacklist + * mark_raw_hash_blacklisted - Add a hash to the system blacklist * @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783") */ -int mark_hash_blacklisted(const char *hash) +static int mark_raw_hash_blacklisted(const char *hash) { key_ref_t key; @@ -133,29 +165,36 @@ int mark_hash_blacklisted(const char *hash) return 0; } +int mark_hash_blacklisted(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type) +{ + const char *buffer; + int err; + + buffer = get_raw_hash(hash, hash_len, hash_type); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + err = mark_raw_hash_blacklisted(buffer); + kfree(buffer); + return err; +} + /** * is_hash_blacklisted - Determine if a hash is blacklisted * @hash: The hash to be checked as a binary blob * @hash_len: The length of the binary hash - * @type: Type of hash + * @hash_type: Type of hash */ -int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type) +int is_hash_blacklisted(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type) { key_ref_t kref; - size_t type_len = strlen(type); - char *buffer, *p; + const char *buffer; int ret = 0; - buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL); - if (!buffer) - return -ENOMEM; - p = memcpy(buffer, type, type_len); - p += type_len; - *p++ = ':'; - bin2hex(p, hash, hash_len); - p += hash_len * 2; - *p = 0; - + buffer = get_raw_hash(hash, hash_len, hash_type); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); kref = keyring_search(make_key_ref(blacklist_keyring, true), &key_type_blacklist, buffer, false); if (!IS_ERR(kref)) { @@ -170,7 +209,8 @@ EXPORT_SYMBOL_GPL(is_hash_blacklisted); int is_binary_blacklisted(const u8 *hash, size_t hash_len) { - if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED) + if (is_hash_blacklisted(hash, hash_len, BLACKLIST_HASH_BINARY) == + -EKEYREJECTED) return -EPERM; return 0; @@ -243,7 +283,7 @@ static int __init blacklist_init(void) panic("Can't allocate system blacklist keyring\n"); for (bl = blacklist_hashes; *bl; bl++) - if (mark_hash_blacklisted(*bl) < 0) + if (mark_raw_hash_blacklisted(*bl) < 0) pr_err("- blacklisting failed\n"); return 0; } diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index ae450eb8be14..3b7dba5e4cd9 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -81,7 +81,8 @@ int x509_get_sig_params(struct x509_certificate *cert) if (ret < 0) goto error_2; - ret = is_hash_blacklisted(sig->digest, sig->digest_size, "tbs"); + ret = is_hash_blacklisted(sig->digest, sig->digest_size, + BLACKLIST_HASH_X509_TBS); if (ret == -EKEYREJECTED) { pr_err("Cert %*phN is blacklisted\n", sig->digest_size, sig->digest); diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h index 875e002a4180..d2597f8d6d7e 100644 --- a/include/keys/system_keyring.h +++ b/include/keys/system_keyring.h @@ -10,6 +10,13 @@ #include +enum blacklist_hash_type { + /* TBSCertificate hash */ + BLACKLIST_HASH_X509_TBS = 1, + /* Raw data hash */ + BLACKLIST_HASH_BINARY = 2, +}; + #ifdef CONFIG_SYSTEM_TRUSTED_KEYRING extern int restrict_link_by_builtin_trusted(struct key *keyring, @@ -33,13 +40,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted( extern struct pkcs7_message *pkcs7; #ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING -extern int mark_hash_blacklisted(const char *hash); +extern int mark_hash_blacklisted(const u8 *hash, size_t hash_len, + enum blacklist_hash_type hash_type); extern int is_hash_blacklisted(const u8 *hash, size_t hash_len, - const char *type); + enum blacklist_hash_type hash_type); extern int is_binary_blacklisted(const u8 *hash, size_t hash_len); #else static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len, - const char *type) + enum blacklist_hash_type hash_type) { return 0; } diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c index 5604bd57c990..9e4f156b356e 100644 --- a/security/integrity/platform_certs/keyring_handler.c +++ b/security/integrity/platform_certs/keyring_handler.c @@ -15,35 +15,13 @@ static efi_guid_t efi_cert_x509_sha256_guid __initdata = EFI_CERT_X509_SHA256_GUID; static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID; -/* - * Blacklist a hash. - */ -static __init void uefi_blacklist_hash(const char *source, const void *data, - size_t len, const char *type, - size_t type_len) -{ - char *hash, *p; - - hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL); - if (!hash) - return; - p = memcpy(hash, type, type_len); - p += type_len; - bin2hex(p, data, len); - p += len * 2; - *p = 0; - - mark_hash_blacklisted(hash); - kfree(hash); -} - /* * Blacklist an X509 TBS hash. */ static __init void uefi_blacklist_x509_tbs(const char *source, const void *data, size_t len) { - uefi_blacklist_hash(source, data, len, "tbs:", 4); + mark_hash_blacklisted(data, len, BLACKLIST_HASH_X509_TBS); } /* @@ -52,7 +30,7 @@ static __init void uefi_blacklist_x509_tbs(const char *source, static __init void uefi_blacklist_binary(const char *source, const void *data, size_t len) { - uefi_blacklist_hash(source, data, len, "bin:", 4); + mark_hash_blacklisted(data, len, BLACKLIST_HASH_BINARY); } /*