From patchwork Mon Jul 12 17:03:09 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: 12371769 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 415B7C07E9C for ; Mon, 12 Jul 2021 17:13:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2109E6124C for ; Mon, 12 Jul 2021 17:13:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233545AbhGLRQS (ORCPT ); Mon, 12 Jul 2021 13:16:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234224AbhGLRQR (ORCPT ); Mon, 12 Jul 2021 13:16:17 -0400 Received: from smtp-42a9.mail.infomaniak.ch (smtp-42a9.mail.infomaniak.ch [IPv6:2001:1600:3:17::42a9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BCD4C0613E8 for ; Mon, 12 Jul 2021 10:13:29 -0700 (PDT) Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4GNqpx3B5bzMpp7K; Mon, 12 Jul 2021 19:03:37 +0200 (CEST) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4GNqpx13Z7zlh8n6; Mon, 12 Jul 2021 19:03:37 +0200 (CEST) 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 v8 1/5] tools/certs: Add print-cert-tbs-hash.sh Date: Mon, 12 Jul 2021 19:03:09 +0200 Message-Id: <20210712170313.884724-2-mic@digikod.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712170313.884724-1-mic@digikod.net> References: <20210712170313.884724-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@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/20210712170313.884724-2-mic@digikod.net --- 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 a61f4f3b78a9..0b3be78d27ef 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4301,6 +4301,7 @@ 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 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 Mon Jul 12 17:03:10 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: 12371767 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 22C7BC07E9A for ; Mon, 12 Jul 2021 17:13:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED8AB611CC for ; Mon, 12 Jul 2021 17:13:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233668AbhGLRQR (ORCPT ); Mon, 12 Jul 2021 13:16:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230255AbhGLRQR (ORCPT ); Mon, 12 Jul 2021 13:16:17 -0400 X-Greylist: delayed 589 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 12 Jul 2021 10:13:28 PDT Received: from smtp-42ab.mail.infomaniak.ch (smtp-42ab.mail.infomaniak.ch [IPv6:2001:1600:3:17::42ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D75DAC0613DD for ; Mon, 12 Jul 2021 10:13:28 -0700 (PDT) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4GNqpy4r1ZzMppR6; Mon, 12 Jul 2021 19:03:38 +0200 (CEST) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4GNqpy2cvhzlh8TR; Mon, 12 Jul 2021 19:03:38 +0200 (CEST) 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 v8 2/5] certs: Check that builtin blacklist hashes are valid Date: Mon, 12 Jul 2021 19:03:10 +0200 Message-Id: <20210712170313.884724-3-mic@digikod.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712170313.884724-1-mic@digikod.net> References: <20210712170313.884724-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@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/20210712170313.884724-3-mic@digikod.net --- Changes since v7: * Rebase and fix trivial .gitignore conflict. 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 $(scrtree)/ (suggested by David Howells). * Fix hexadecimal number check. --- MAINTAINERS | 1 + certs/.gitignore | 1 + certs/Kconfig | 7 ++++-- certs/Makefile | 17 +++++++++++++- scripts/check-blacklist-hashes.awk | 37 ++++++++++++++++++++++++++++++ 5 files changed, 60 insertions(+), 3 deletions(-) create mode 100755 scripts/check-blacklist-hashes.awk diff --git a/MAINTAINERS b/MAINTAINERS index 0b3be78d27ef..04b8fb5dcdac 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4299,6 +4299,7 @@ L: keyrings@vger.kernel.org S: Maintained F: Documentation/admin-guide/module-signing.rst F: certs/ +F: scripts/check-blacklist-hashes.awk F: scripts/extract-cert.c F: scripts/sign-file.c F: tools/certs/ diff --git a/certs/.gitignore b/certs/.gitignore index 8c3763f80be3..01de9442e4e2 100644 --- a/certs/.gitignore +++ b/certs/.gitignore @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only +/blacklist_hashes_checked /x509_certificate_list /x509_revocation_list diff --git a/certs/Kconfig b/certs/Kconfig index f4e61116f94e..0fbe184ceca5 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -80,8 +80,11 @@ config SYSTEM_BLACKLIST_HASH_LIST help If set, this option should be the filename of a list of hashes in the form "", "", ... . This will be included into a C - wrapper to incorporate the list into the kernel. Each should - be a string of hex digits. + wrapper to incorporate the list into the kernel. Each must be a + string starting with a prefix ("tbs" or "bin"), then a colon (":"), and + finally an even number of hexadecimal lowercase characters (up to 128). + Certificate hashes can be generated with + tools/certs/print-cert-tbs-hash.sh . config SYSTEM_REVOCATION_LIST bool "Provide system-wide ring of revocation certificates" diff --git a/certs/Makefile b/certs/Makefile index 359239a0ee9e..e43c1a8032de 100644 --- a/certs/Makefile +++ b/certs/Makefile @@ -7,7 +7,22 @@ obj-$(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) SIGN_KEY = 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 Mon Jul 12 17:03:11 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: 12371759 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 B94D3C11F67 for ; Mon, 12 Jul 2021 17:12:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5DAF61260 for ; Mon, 12 Jul 2021 17:12:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235167AbhGLRPL (ORCPT ); Mon, 12 Jul 2021 13:15:11 -0400 Received: from smtp-42aa.mail.infomaniak.ch ([84.16.66.170]:38033 "EHLO smtp-42aa.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235038AbhGLRPL (ORCPT ); Mon, 12 Jul 2021 13:15:11 -0400 Received: from smtp-3-0001.mail.infomaniak.ch (unknown [10.4.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4GNqpz6tdDzMpnSJ; Mon, 12 Jul 2021 19:03:39 +0200 (CEST) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4GNqpz4Qnkzlmrrn; Mon, 12 Jul 2021 19:03:39 +0200 (CEST) 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 v8 3/5] certs: Make blacklist_vet_description() more strict Date: Mon, 12 Jul 2021 19:03:11 +0200 Message-Id: <20210712170313.884724-4-mic@digikod.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712170313.884724-1-mic@digikod.net> References: <20210712170313.884724-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org From: Mickaël Salaün Before exposing this new key type to user space, make sure that only meaningful blacklisted hashes are accepted. This is also checked for builtin blacklisted hashes, but a following commit make sure that the user will notice (at built time) and will fix the configuration if it already included errors. Check that a blacklist key description starts with a valid prefix and then a valid hexadecimal string. Cc: David Howells Cc: David Woodhouse Cc: Eric Snowberg Signed-off-by: Mickaël Salaün Reviewed-by: Jarkko Sakkinen Link: https://lore.kernel.org/r/20210712170313.884724-4-mic@digikod.net --- Changes since v5: * Add Reviewed-by Jarkko. Changes since v2: * Fix typo in blacklist_vet_description() comment, spotted by Tyler Hicks. * Add Jarkko's Acked-by. Changes since v1: * Return ENOPKG (instead of EINVAL) when a hash is greater than the maximum currently known hash (suggested by David Howells). --- certs/blacklist.c | 46 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index c9a435b15af4..97a35cf9a62c 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -19,6 +19,16 @@ #include "blacklist.h" #include "common.h" +/* + * According to crypto/asymmetric_keys/x509_cert_parser.c:x509_note_pkey_algo(), + * the size of the currently longest supported hash algorithm is 512 bits, + * which translates into 128 hex characters. + */ +#define MAX_HASH_LEN 128 + +static const char tbs_prefix[] = "tbs"; +static const char bin_prefix[] = "bin"; + static struct key *blacklist_keyring; #ifdef CONFIG_SYSTEM_REVOCATION_LIST @@ -32,24 +42,40 @@ extern __initconst const unsigned long revocation_certificate_list_size; */ static int blacklist_vet_description(const char *desc) { - int n = 0; - - if (*desc == ':') - return -EINVAL; - for (; *desc; desc++) - if (*desc == ':') - goto found_colon; + int i, prefix_len, tbs_step = 0, bin_step = 0; + + /* The following algorithm only works if prefix lengths match. */ + BUILD_BUG_ON(sizeof(tbs_prefix) != sizeof(bin_prefix)); + prefix_len = sizeof(tbs_prefix) - 1; + for (i = 0; *desc; desc++, i++) { + if (*desc == ':') { + if (tbs_step == prefix_len) + goto found_colon; + if (bin_step == prefix_len) + goto found_colon; + return -EINVAL; + } + if (i >= prefix_len) + return -EINVAL; + if (*desc == tbs_prefix[i]) + tbs_step++; + if (*desc == bin_prefix[i]) + bin_step++; + } return -EINVAL; found_colon: desc++; - for (; *desc; desc++) { + for (i = 0; *desc && i < MAX_HASH_LEN; desc++, i++) { if (!isxdigit(*desc) || isupper(*desc)) return -EINVAL; - n++; } + if (*desc) + /* The hash is greater than MAX_HASH_LEN. */ + return -ENOPKG; - if (n == 0 || n & 1) + /* Checks for an even number of hexadecimal characters. */ + if (i == 0 || i & 1) return -EINVAL; return 0; } From patchwork Mon Jul 12 17:03:12 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: 12371761 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 06F4AC11F6A for ; Mon, 12 Jul 2021 17:12:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E13EA61279 for ; Mon, 12 Jul 2021 17:12:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234995AbhGLRPL (ORCPT ); Mon, 12 Jul 2021 13:15:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235131AbhGLRPL (ORCPT ); Mon, 12 Jul 2021 13:15:11 -0400 Received: from smtp-42aa.mail.infomaniak.ch (smtp-42aa.mail.infomaniak.ch [IPv6:2001:1600:4:17::42aa]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC401C0613E9 for ; Mon, 12 Jul 2021 10:12:22 -0700 (PDT) Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4GNqq11FLpzMprg6; Mon, 12 Jul 2021 19:03:41 +0200 (CEST) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4GNqq06CyYzlh8n6; Mon, 12 Jul 2021 19:03:40 +0200 (CEST) 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 v8 4/5] certs: Factor out the blacklist hash creation Date: Mon, 12 Jul 2021 19:03:12 +0200 Message-Id: <20210712170313.884724-5-mic@digikod.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712170313.884724-1-mic@digikod.net> References: <20210712170313.884724-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@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/20210712170313.884724-5-mic@digikod.net --- 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 3d45161b271a..4b3d5166643b 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 6acd3cf13a18..1efb52bc494f 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, @@ -40,13 +47,14 @@ 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); } /* From patchwork Mon Jul 12 17:03:13 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: 12371755 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 430BCC07E99 for ; Mon, 12 Jul 2021 17:12:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24B5A61222 for ; Mon, 12 Jul 2021 17:12:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234994AbhGLRPL (ORCPT ); Mon, 12 Jul 2021 13:15:11 -0400 Received: from smtp-1908.mail.infomaniak.ch ([185.125.25.8]:47177 "EHLO smtp-1908.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230255AbhGLRPK (ORCPT ); Mon, 12 Jul 2021 13:15:10 -0400 X-Greylist: delayed 521 seconds by postgrey-1.27 at vger.kernel.org; Mon, 12 Jul 2021 13:15:10 EDT Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4GNqq23KRvzMpnT0; Mon, 12 Jul 2021 19:03:42 +0200 (CEST) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4GNqq218RMzlh8TM; Mon, 12 Jul 2021 19:03:42 +0200 (CEST) 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 v8 5/5] certs: Allow root user to append signed hashes to the blacklist keyring Date: Mon, 12 Jul 2021 19:03:13 +0200 Message-Id: <20210712170313.884724-6-mic@digikod.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712170313.884724-1-mic@digikod.net> References: <20210712170313.884724-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org From: Mickaël Salaün Add a kernel option SYSTEM_BLACKLIST_AUTH_UPDATE to enable the root user to dynamically add new keys to the blacklist keyring. This enables to invalidate new certificates, either from being loaded in a keyring, or from being trusted in a PKCS#7 certificate chain. This also enables to add new file hashes to be denied by the integrity infrastructure. Being able to untrust a certificate which could have normaly been trusted is a sensitive operation. This is why adding new hashes to the blacklist keyring is only allowed when these hashes are signed and vouched by the builtin trusted keyring. A blacklist hash is stored as a key description. The PKCS#7 signature of this description must be provided as the key payload. Marking a certificate as untrusted should be enforced while the system is running. It is then forbiden to remove such blacklist keys. Update blacklist keyring, blacklist key and revoked certificate access rights: * allows the root user to search for a specific blacklisted hash, which make sense because the descriptions are already viewable; * forbids key update (blacklist and asymmetric ones); * restricts kernel rights on the blacklist keyring to align with the root user rights. See help in tools/certs/print-cert-tbs-hash.sh . Cc: David Howells Cc: David Woodhouse Cc: Eric Snowberg Cc: Jarkko Sakkinen Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20210712170313.884724-6-mic@digikod.net --- 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, fix Kconfig conflict, and update the asymmetric key rights added to the blacklist keyring by the new add_key_to_revocation_list(): align with blacklist key rights by removing KEY_POS_WRITE as a safeguard, and add KEY_ALLOC_BYPASS_RESTRICTION to not be subject to restrict_link_for_blacklist() that only allows blacklist key types to be added to the keyring. * Change the return code for restrict_link_for_blacklist() from -EPERM to -EOPNOTSUPP to align with asymmetric key keyrings. Changes since v3: * Update commit message for print-cert-tbs-hash.sh . Changes since v2: * Add comment for blacklist_key_instantiate(). --- certs/Kconfig | 10 +++++ certs/blacklist.c | 96 ++++++++++++++++++++++++++++++++++++----------- 2 files changed, 85 insertions(+), 21 deletions(-) diff --git a/certs/Kconfig b/certs/Kconfig index 0fbe184ceca5..e0e524b7eff9 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -103,4 +103,14 @@ config SYSTEM_REVOCATION_KEYS containing X.509 certificates to be included in the default blacklist keyring. +config SYSTEM_BLACKLIST_AUTH_UPDATE + bool "Allow root to add signed blacklist keys" + depends on SYSTEM_BLACKLIST_KEYRING + depends on SYSTEM_DATA_VERIFICATION + help + If set, provide the ability to load new blacklist keys at run time if + they are signed and vouched by a certificate from the builtin trusted + keyring. The PKCS#7 signature of the description is set in the key + payload. Blacklist keys cannot be removed. + endmenu diff --git a/certs/blacklist.c b/certs/blacklist.c index b254c87ceb3a..486ce0dd8e9c 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include "blacklist.h" #include "common.h" @@ -26,6 +27,9 @@ */ #define MAX_HASH_LEN 128 +#define BLACKLIST_KEY_PERM (KEY_POS_SEARCH | KEY_POS_VIEW | \ + KEY_USR_SEARCH | KEY_USR_VIEW) + static const char tbs_prefix[] = "tbs"; static const char bin_prefix[] = "bin"; @@ -80,19 +84,51 @@ static int blacklist_vet_description(const char *desc) return 0; } -/* - * The hash to be blacklisted is expected to be in the description. There will - * be no payload. - */ -static int blacklist_preparse(struct key_preparsed_payload *prep) +static int blacklist_key_instantiate(struct key *key, + struct key_preparsed_payload *prep) { - if (prep->datalen > 0) - return -EINVAL; - return 0; +#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE + int err; +#endif + + /* Sets safe default permissions for keys loaded by user space. */ + key->perm = BLACKLIST_KEY_PERM; + + /* + * Skips the authentication step for builtin hashes, they are not + * signed but still trusted. + */ + if (key->flags & (1 << KEY_FLAG_BUILTIN)) + goto out; + +#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE + /* + * Verifies the description's PKCS#7 signature against the builtin + * trusted keyring. + */ + err = verify_pkcs7_signature(key->description, + strlen(key->description), prep->data, prep->datalen, + NULL, VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL); + if (err) + return err; +#else + /* + * It should not be possible to come here because the keyring doesn't + * have KEY_USR_WRITE and the only other way to call this function is + * for builtin hashes. + */ + WARN_ON_ONCE(1); + return -EPERM; +#endif + +out: + return generic_key_instantiate(key, prep); } -static void blacklist_free_preparse(struct key_preparsed_payload *prep) +static int blacklist_key_update(struct key *key, + struct key_preparsed_payload *prep) { + return -EPERM; } static void blacklist_describe(const struct key *key, struct seq_file *m) @@ -103,9 +139,8 @@ static void blacklist_describe(const struct key *key, struct seq_file *m) static struct key_type key_type_blacklist = { .name = "blacklist", .vet_description = blacklist_vet_description, - .preparse = blacklist_preparse, - .free_preparse = blacklist_free_preparse, - .instantiate = generic_key_instantiate, + .instantiate = blacklist_key_instantiate, + .update = blacklist_key_update, .describe = blacklist_describe, }; @@ -154,8 +189,7 @@ static int mark_raw_hash_blacklisted(const char *hash) hash, NULL, 0, - ((KEY_POS_ALL & ~KEY_POS_SETATTR) | - KEY_USR_VIEW), + BLACKLIST_KEY_PERM, KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); if (IS_ERR(key)) { @@ -232,8 +266,10 @@ int add_key_to_revocation_list(const char *data, size_t size) NULL, data, size, - ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW), - KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); + KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH + | KEY_USR_VIEW, + KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN + | KEY_ALLOC_BYPASS_RESTRICTION); if (IS_ERR(key)) { pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key)); @@ -260,25 +296,43 @@ int is_key_on_revocation_list(struct pkcs7_message *pkcs7) } #endif +static int restrict_link_for_blacklist(struct key *dest_keyring, + const struct key_type *type, const union key_payload *payload, + struct key *restrict_key) +{ + if (type == &key_type_blacklist) + return 0; + return -EOPNOTSUPP; +} + /* * Initialise the blacklist */ static int __init blacklist_init(void) { const char *const *bl; + struct key_restriction *restriction; if (register_key_type(&key_type_blacklist) < 0) panic("Can't allocate system blacklist key type\n"); + restriction = kzalloc(sizeof(*restriction), GFP_KERNEL); + if (!restriction) + panic("Can't allocate blacklist keyring restriction\n"); + restriction->check = restrict_link_for_blacklist; + blacklist_keyring = keyring_alloc(".blacklist", GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), - (KEY_POS_ALL & ~KEY_POS_SETATTR) | - KEY_USR_VIEW | KEY_USR_READ | - KEY_USR_SEARCH, - KEY_ALLOC_NOT_IN_QUOTA | + KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | + KEY_POS_WRITE | + KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH +#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE + | KEY_USR_WRITE +#endif + , KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_SET_KEEP, - NULL, NULL); + restriction, NULL); if (IS_ERR(blacklist_keyring)) panic("Can't allocate system blacklist keyring\n");