From patchwork Thu Jan 21 15:55:04 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: 12037111 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 6F3EBC43381 for ; Thu, 21 Jan 2021 16:52:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 30F9223A3C for ; Thu, 21 Jan 2021 16:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731094AbhAUQwM (ORCPT ); Thu, 21 Jan 2021 11:52:12 -0500 Received: from smtp-190e.mail.infomaniak.ch ([185.125.25.14]:45077 "EHLO smtp-190e.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731039AbhAUP4W (ORCPT ); Thu, 21 Jan 2021 10:56:22 -0500 Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rc2ptdzMprhV; Thu, 21 Jan 2021 16:55:24 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rc0j8qzlh8TC; Thu, 21 Jan 2021 16:55:24 +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" , 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 v4 01/10] tools/certs: Add print-cert-tbs-hash.sh Date: Thu, 21 Jan 2021 16:55:04 +0100 Message-Id: <20210121155513.539519-2-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: 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 Signed-off-by: Mickaël Salaün --- 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 Thu Jan 21 15:55:05 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: 12037113 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 4CE64C433E9 for ; Thu, 21 Jan 2021 16:52:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05E1523A55 for ; Thu, 21 Jan 2021 16:52:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731791AbhAUQwL (ORCPT ); Thu, 21 Jan 2021 11:52:11 -0500 Received: from smtp-8fa9.mail.infomaniak.ch ([83.166.143.169]:42025 "EHLO smtp-8fa9.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731094AbhAUP4d (ORCPT ); Thu, 21 Jan 2021 10:56:33 -0500 Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rd4TrPzMr5H6; Thu, 21 Jan 2021 16:55:25 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rd2K7fzlh8TL; Thu, 21 Jan 2021 16:55:25 +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" , 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 v4 02/10] certs: Check that builtin blacklist hashes are valid Date: Thu, 21 Jan 2021 16:55:05 +0100 Message-Id: <20210121155513.539519-3-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: 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: Jarkko Sakkinen Signed-off-by: Mickaël Salaün --- 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 $(scrtree)/ (suggested by David Howells). * Fix hexadecimal number check. --- MAINTAINERS | 1 + certs/.gitignore | 1 + certs/Kconfig | 7 ++++-- certs/Makefile | 15 +++++++++++- scripts/check-blacklist-hashes.awk | 37 ++++++++++++++++++++++++++++++ 5 files changed, 58 insertions(+), 3 deletions(-) create mode 100755 scripts/check-blacklist-hashes.awk diff --git a/MAINTAINERS b/MAINTAINERS index 773a362e807f..a18fd3d283c6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4118,6 +4118,7 @@ L: keyrings@vger.kernel.org S: Maintained F: Documentation/admin-guide/module-signing.rst F: certs/ +F: scripts/check-blacklist-hashes.awk F: scripts/extract-cert.c F: scripts/sign-file.c F: tools/certs/ diff --git a/certs/.gitignore b/certs/.gitignore index 2a2483990686..42cc2ac24b93 100644 --- a/certs/.gitignore +++ b/certs/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only +blacklist_hashes_checked x509_certificate_list diff --git a/certs/Kconfig b/certs/Kconfig index c94e93d8bccf..6d09dec4a9e3 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -80,7 +80,10 @@ config SYSTEM_BLACKLIST_HASH_LIST help If set, this option should be the filename of a list of hashes in the form "", "", ... . This will be included into a C - wrapper to incorporate the list into the kernel. Each should - be a string of hex digits. + wrapper to incorporate the list into the kernel. Each must be a + string starting with a prefix ("tbs" or "bin"), then a colon (":"), and + finally an even number of hexadecimal lowercase characters (up to 128). + Certificate hashes can be generated with + tools/certs/print-cert-tbs-hash.sh . endmenu diff --git a/certs/Makefile b/certs/Makefile index f4c25b67aad9..eb45407ff282 100644 --- a/certs/Makefile +++ b/certs/Makefile @@ -6,7 +6,20 @@ obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o ifneq ($(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: $(obj)/blacklist_hashes_checked + +targets += blacklist_hashes_checked +$(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 @@ -29,7 +42,7 @@ $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREF $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS)) endif # CONFIG_SYSTEM_TRUSTED_KEYRING -clean-files := x509_certificate_list .x509.list +clean-files := x509_certificate_list .x509.list blacklist_hashes_checked ifeq ($(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 Thu Jan 21 15:55:06 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: 12037063 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 388C9C43381 for ; Thu, 21 Jan 2021 16:51:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAABB23A53 for ; Thu, 21 Jan 2021 16:51:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387939AbhAUQuv (ORCPT ); Thu, 21 Jan 2021 11:50:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43284 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731726AbhAUP6I (ORCPT ); Thu, 21 Jan 2021 10:58:08 -0500 Received: from smtp-42ae.mail.infomaniak.ch (smtp-42ae.mail.infomaniak.ch [IPv6:2001:1600:4:17::42ae]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB2C8C06178C; Thu, 21 Jan 2021 07:55:28 -0800 (PST) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rf695LzMpwDb; Thu, 21 Jan 2021 16:55:26 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rf43Fczlh8TL; Thu, 21 Jan 2021 16:55:26 +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" , 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, Ben Boeckel Subject: [PATCH v4 03/10] certs: Fix blacklisted hexadecimal hash string check Date: Thu, 21 Jan 2021 16:55:06 +0100 Message-Id: <20210121155513.539519-4-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: Mickaël Salaün When looking for a blacklisted hash, bin2hex() is used to transform a binary hash to an ascii (lowercase) hexadecimal string. This string is then search for in the description of the keys from the blacklist keyring. When adding a key to the blacklist keyring, blacklist_vet_description() checks the hash prefix and the hexadecimal string, but not that this string is lowercase. It is then valid to set hashes with uppercase hexadecimal, which will be silently ignored by the kernel. Add an additional check to blacklist_vet_description() to check that hexadecimal strings are in lowercase. Cc: David Woodhouse Signed-off-by: Mickaël Salaün Signed-off-by: David Howells Reviewed-by: Ben Boeckel --- Changes since v2: * Cherry-pick v1 patch from https://lore.kernel.org/lkml/2659836.1607940186@warthog.procyon.org.uk/ to rebase on v5.11-rc3. * Rearrange Cc order. --- certs/blacklist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 6514f9ebc943..4e1a58170d5c 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -37,7 +37,7 @@ static int blacklist_vet_description(const char *desc) found_colon: desc++; for (; *desc; desc++) { - if (!isxdigit(*desc)) + if (!isxdigit(*desc) || isupper(*desc)) return -EINVAL; n++; } From patchwork Thu Jan 21 15:55:07 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: 12037109 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 EDBE6C433DB for ; Thu, 21 Jan 2021 16:51:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A48F523A55 for ; Thu, 21 Jan 2021 16:51:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731974AbhAUQvf (ORCPT ); Thu, 21 Jan 2021 11:51:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731731AbhAUP5u (ORCPT ); Thu, 21 Jan 2021 10:57:50 -0500 Received: from smtp-bc0b.mail.infomaniak.ch (smtp-bc0b.mail.infomaniak.ch [IPv6:2001:1600:3:17::bc0b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 641F4C061794 for ; Thu, 21 Jan 2021 07:55:30 -0800 (PST) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rh3kCQzMr37d; Thu, 21 Jan 2021 16:55:28 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rh1G3Pzlpq00; Thu, 21 Jan 2021 16:55:28 +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" , 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, Mimi Zohar Subject: [PATCH v4 04/10] certs: Fix blacklist flag type confusion Date: Thu, 21 Jan 2021 16:55:07 +0100 Message-Id: <20210121155513.539519-5-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: David Howells KEY_FLAG_KEEP is not meant to be passed to keyring_alloc() or key_alloc(), as these only take KEY_ALLOC_* flags. KEY_FLAG_KEEP has the same value as KEY_ALLOC_BYPASS_RESTRICTION, but fortunately only key_create_or_update() uses it. LSMs using the key_alloc hook don't check that flag. KEY_FLAG_KEEP is then ignored but fortunately (again) the root user cannot write to the blacklist keyring, so it is not possible to remove a key/hash from it. Fix this by adding a KEY_ALLOC_SET_KEEP flag that tells key_alloc() to set KEY_FLAG_KEEP on the new key. blacklist_init() can then, correctly, pass this to keyring_alloc(). ima_mok_init() allocates another blacklist keyring (with different properties) dedicated to IMA. We can also use KEY_ALLOC_SET_KEEP in ima_mok_init() rather than setting the flag manually. Note that this doesn't fix an observable bug with the current implementation but it is required to allow addition of new hashes to the blacklist in the future without making it possible for them to be removed or modified. Fixes: 734114f8782f ("KEYS: Add a system blacklist keyring") Cc: Mimi Zohar Cc: David Woodhouse Reported-by: Mickaël Salaün Signed-off-by: David Howells [mic@linux.microsoft.com: Fix argument bit-ORing in ima_mok_init() and extend commit description] Signed-off-by: Mickaël Salaün Acked-by: Jarkko Sakkinen --- Changes since v3: * Extend ima_mok_init() description (suggested by Jarkko Sakkinen). * Add Acked-by Jarkko Sakkinen. Changes since v2: * Cherry-pick rewritten v1 patch from https://lore.kernel.org/lkml/2659836.1607940186@warthog.procyon.org.uk/ to rebase on v5.11-rc3 and fix ima_mok_init(). --- certs/blacklist.c | 2 +- include/linux/key.h | 1 + security/integrity/ima/ima_mok.c | 4 +--- security/keys/key.c | 2 ++ 4 files changed, 5 insertions(+), 4 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 4e1a58170d5c..446818e90b54 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -162,7 +162,7 @@ static int __init blacklist_init(void) KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH, KEY_ALLOC_NOT_IN_QUOTA | - KEY_FLAG_KEEP, + KEY_ALLOC_SET_KEEP, NULL, NULL); if (IS_ERR(blacklist_keyring)) panic("Can't allocate system blacklist keyring\n"); diff --git a/include/linux/key.h b/include/linux/key.h index 0f2e24f13c2b..eed3ce139a32 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -289,6 +289,7 @@ extern struct key *key_alloc(struct key_type *type, #define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */ #define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */ #define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */ +#define KEY_ALLOC_SET_KEEP 0x0020 /* Set the KEEP flag on the key/keyring */ extern void key_revoke(struct key *key); extern void key_invalidate(struct key *key); diff --git a/security/integrity/ima/ima_mok.c b/security/integrity/ima/ima_mok.c index 36cadadbfba4..5594dd38ab04 100644 --- a/security/integrity/ima/ima_mok.c +++ b/security/integrity/ima/ima_mok.c @@ -38,13 +38,11 @@ __init int ima_mok_init(void) (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_WRITE | KEY_USR_SEARCH, - KEY_ALLOC_NOT_IN_QUOTA, + KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_SET_KEEP, restriction, NULL); if (IS_ERR(ima_blacklist_keyring)) panic("Can't allocate IMA blacklist keyring."); - - set_bit(KEY_FLAG_KEEP, &ima_blacklist_keyring->flags); return 0; } device_initcall(ima_mok_init); diff --git a/security/keys/key.c b/security/keys/key.c index ebe752b137aa..c45afdd1dfbb 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -303,6 +303,8 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->flags |= 1 << KEY_FLAG_BUILTIN; if (flags & KEY_ALLOC_UID_KEYRING) key->flags |= 1 << KEY_FLAG_UID_KEYRING; + if (flags & KEY_ALLOC_SET_KEEP) + key->flags |= 1 << KEY_FLAG_KEEP; #ifdef KEY_DEBUGGING key->magic = KEY_DEBUG_MAGIC; From patchwork Thu Jan 21 15:55:08 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: 12036845 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=ham 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 03FD8C433E6 for ; Thu, 21 Jan 2021 15:57:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B73F4238A0 for ; Thu, 21 Jan 2021 15:57:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731525AbhAUP5m (ORCPT ); Thu, 21 Jan 2021 10:57:42 -0500 Received: from smtp-8fa9.mail.infomaniak.ch ([83.166.143.169]:32903 "EHLO smtp-8fa9.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731413AbhAUP5N (ORCPT ); Thu, 21 Jan 2021 10:57:13 -0500 Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rj6QQxzMr5H9; Thu, 21 Jan 2021 16:55:29 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rj43ZDzlppyh; Thu, 21 Jan 2021 16:55:29 +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" , 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 v4 05/10] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Date: Thu, 21 Jan 2021 16:55:08 +0100 Message-Id: <20210121155513.539519-6-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: Mickaël Salaün Use GLOBAL_ROOT_UID and GLOBAL_ROOT_GID definitions, and add appropriate include files. Cc: David Woodhouse Signed-off-by: Mickaël Salaün Signed-off-by: David Howells --- Changes since v2: * Cherry-pick v1 patch from https://lore.kernel.org/lkml/2659836.1607940186@warthog.procyon.org.uk/ to rebase on v5.11-rc3. --- certs/blacklist.c | 4 ++-- certs/system_keyring.c | 5 +++-- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 446818e90b54..8a64b9e89cae 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include "blacklist.h" @@ -156,8 +157,7 @@ static int __init blacklist_init(void) blacklist_keyring = keyring_alloc(".blacklist", - KUIDT_INIT(0), KGIDT_INIT(0), - current_cred(), + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH, diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 798291177186..4b693da488f1 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -98,7 +99,7 @@ static __init int system_trusted_keyring_init(void) builtin_trusted_keys = keyring_alloc(".builtin_trusted_keys", - KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), + 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, @@ -109,7 +110,7 @@ static __init int system_trusted_keyring_init(void) #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING secondary_trusted_keys = keyring_alloc(".secondary_trusted_keys", - KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), ((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH | KEY_USR_WRITE), From patchwork Thu Jan 21 15:55:09 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: 12037067 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 4C766C433E6 for ; Thu, 21 Jan 2021 16:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04B2223A56 for ; Thu, 21 Jan 2021 16:51:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731953AbhAUQvA (ORCPT ); Thu, 21 Jan 2021 11:51:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731897AbhAUP6I (ORCPT ); Thu, 21 Jan 2021 10:58:08 -0500 Received: from smtp-190e.mail.infomaniak.ch (smtp-190e.mail.infomaniak.ch [IPv6:2001:1600:4:17::190e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA4FFC0617AB for ; Thu, 21 Jan 2021 07:55:32 -0800 (PST) Received: from smtp-3-0000.mail.infomaniak.ch (unknown [10.4.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rl18rszMpnPf; Thu, 21 Jan 2021 16:55:31 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rk5yXDzlh8TW; Thu, 21 Jan 2021 16:55:30 +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" , 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 v4 06/10] certs: Make blacklist_vet_description() more strict Date: Thu, 21 Jan 2021 16:55:09 +0100 Message-Id: <20210121155513.539519-7-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: 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 Signed-off-by: Mickaël Salaün Acked-by: Jarkko Sakkinen --- 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 8a64b9e89cae..069050884bd2 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -18,6 +18,16 @@ #include #include "blacklist.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; /* @@ -26,24 +36,40 @@ static struct key *blacklist_keyring; */ 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 Thu Jan 21 15:55:10 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: 12037065 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 2B2BFC433DB for ; Thu, 21 Jan 2021 16:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB57723A53 for ; Thu, 21 Jan 2021 16:51:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731943AbhAUQu6 (ORCPT ); Thu, 21 Jan 2021 11:50:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731953AbhAUP6I (ORCPT ); Thu, 21 Jan 2021 10:58:08 -0500 Received: from smtp-bc0d.mail.infomaniak.ch (smtp-bc0d.mail.infomaniak.ch [IPv6:2001:1600:3:17::bc0d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CB03C061352 for ; Thu, 21 Jan 2021 07:55:34 -0800 (PST) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rm4WDMzMr6dq; Thu, 21 Jan 2021 16:55:32 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rm1Cf9zlppys; Thu, 21 Jan 2021 16:55:32 +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" , 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, Alex Shi , Ben Boeckel Subject: [PATCH v4 07/10] certs/blacklist: fix kernel doc interface issue Date: Thu, 21 Jan 2021 16:55:10 +0100 Message-Id: <20210121155513.539519-8-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: Alex Shi certs/blacklist.c:84: warning: Function parameter or member 'hash' not described in 'mark_hash_blacklisted' Cc: David Woodhouse Cc: keyrings@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Alex Shi Signed-off-by: David Howells Reviewed-by: Ben Boeckel Signed-off-by: Mickaël Salaün Reviewed-by: Jarkko Sakkinen --- Changes since v3: * Add Reviewed-by Jarkko Sakkinen. Changes since v2: * Cherry-pick patch from https://lore.kernel.org/lkml/2659836.1607940186@warthog.procyon.org.uk/ to avoid future merge conflicts. * Rearrange Signed-off-by and Reviewed-by order. --- certs/blacklist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 069050884bd2..334ab7b964bc 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -105,7 +105,7 @@ static struct key_type key_type_blacklist = { /** * mark_hash_blacklisted - Add a hash to the system blacklist - * @hash - The hash as a hex string with a type prefix (eg. "tbs:23aa429783") + * @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783") */ int mark_hash_blacklisted(const char *hash) { From patchwork Thu Jan 21 15:55:11 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: 12037059 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 411F2C433DB for ; Thu, 21 Jan 2021 16:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5ED023A3C for ; Thu, 21 Jan 2021 16:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729940AbhAUP6a (ORCPT ); Thu, 21 Jan 2021 10:58:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732052AbhAUP6Y (ORCPT ); Thu, 21 Jan 2021 10:58:24 -0500 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 2F40DC061356 for ; Thu, 21 Jan 2021 07:55:36 -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 4DM6Rp69g2zMqbYZ; Thu, 21 Jan 2021 16:55:34 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rn480Nzlh8Tc; Thu, 21 Jan 2021 16:55:33 +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" , 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 v4 08/10] certs: Factor out the blacklist hash creation Date: Thu, 21 Jan 2021 16:55:11 +0100 Message-Id: <20210121155513.539519-9-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: 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: Herbert Xu Signed-off-by: Mickaël Salaün Acked-by: Jarkko Sakkinen --- Changes since v2: * Add Jarkko's Acked-by. --- certs/blacklist.c | 73 ++++++++++++++----- crypto/asymmetric_keys/x509_public_key.c | 3 +- include/keys/system_keyring.h | 14 +++- .../platform_certs/keyring_handler.c | 26 +------ 4 files changed, 70 insertions(+), 46 deletions(-) diff --git a/certs/blacklist.c b/certs/blacklist.c index 334ab7b964bc..1e63971bea94 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -103,11 +103,43 @@ 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; @@ -127,29 +159,33 @@ 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; + + buffer = get_raw_hash(hash, hash_len, hash_type); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + kfree(buffer); + return 0; +} /** * 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)) { @@ -164,7 +200,8 @@ 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; @@ -194,7 +231,7 @@ 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 fb8b07daa9d1..b184d8743e23 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, @@ -32,13 +39,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted( #endif #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 c5ba695c10e3..4a78fa1fde53 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 Thu Jan 21 15:55:12 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: 12037061 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,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 A54B2C433E9 for ; Thu, 21 Jan 2021 16:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D8D423A3C for ; Thu, 21 Jan 2021 16:50:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733047AbhAUQuN (ORCPT ); Thu, 21 Jan 2021 11:50:13 -0500 Received: from smtp-8fa9.mail.infomaniak.ch ([83.166.143.169]:45615 "EHLO smtp-8fa9.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731642AbhAUP6J (ORCPT ); Thu, 21 Jan 2021 10:58:09 -0500 Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rr1BKfzMr5GF; Thu, 21 Jan 2021 16:55:36 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rq5lVXzlppys; Thu, 21 Jan 2021 16:55:35 +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" , 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, Ben Boeckel Subject: [PATCH v4 09/10] PKCS#7: Fix missing include Date: Thu, 21 Jan 2021 16:55:12 +0100 Message-Id: <20210121155513.539519-10-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: From: Mickaël Salaün Add missing linux/types.h for size_t. [DH: Changed from stddef.h] Signed-off-by: Mickaël Salaün Signed-off-by: David Howells Reviewed-by: Ben Boeckel Reviewed-by: Jarkko Sakkinen --- Changes since v3: * Add Reviewed-by Jarkko Sakkinen. Changes since v2: * Cherry-pick v1 patch from https://lore.kernel.org/lkml/2659836.1607940186@warthog.procyon.org.uk/ to rebase on v5.11-rc3. --- include/linux/verification.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/verification.h b/include/linux/verification.h index 911ab7c2b1ab..a655923335ae 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -8,6 +8,8 @@ #ifndef _LINUX_VERIFICATION_H #define _LINUX_VERIFICATION_H +#include + /* * Indicate that both builtin trusted keys and secondary trusted keys * should be used. From patchwork Thu Jan 21 15:55:13 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: 12037057 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 AC63DC433DB for ; Thu, 21 Jan 2021 16:49:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 462FC23A33 for ; Thu, 21 Jan 2021 16:49:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732565AbhAUQsf (ORCPT ); Thu, 21 Jan 2021 11:48:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732418AbhAUP6j (ORCPT ); Thu, 21 Jan 2021 10:58:39 -0500 Received: from smtp-bc0d.mail.infomaniak.ch (smtp-bc0d.mail.infomaniak.ch [IPv6:2001:1600:3:17::bc0d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B727BC06121E; Thu, 21 Jan 2021 07:55:39 -0800 (PST) Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DM6Rt3tfRzMr6Zf; Thu, 21 Jan 2021 16:55:38 +0100 (CET) Received: from localhost (unknown [23.97.221.149]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4DM6Rs17JVzlh8Tg; Thu, 21 Jan 2021 16:55:37 +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" , 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 v4 10/10] certs: Allow root user to append signed hashes to the blacklist keyring Date: Thu, 21 Jan 2021 16:55:13 +0100 Message-Id: <20210121155513.539519-11-mic@digikod.net> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210121155513.539519-1-mic@digikod.net> References: <20210121155513.539519-1-mic@digikod.net> MIME-Version: 1.0 Precedence: bulk List-ID: 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 and blacklist key 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; * 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 Signed-off-by: Mickaël Salaün --- 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 | 90 +++++++++++++++++++++++++++++++++++++---------- 2 files changed, 81 insertions(+), 19 deletions(-) diff --git a/certs/Kconfig b/certs/Kconfig index 6d09dec4a9e3..16003ce65b0a 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -86,4 +86,14 @@ config SYSTEM_BLACKLIST_HASH_LIST Certificate hashes can be generated with tools/certs/print-cert-tbs-hash.sh . +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 1e63971bea94..07c592ae5307 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include "blacklist.h" @@ -25,6 +26,9 @@ */ #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"; @@ -74,19 +78,51 @@ 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) @@ -97,9 +133,8 @@ 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, }; @@ -148,8 +183,7 @@ 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)) { @@ -208,25 +242,43 @@ int is_binary_blacklisted(const u8 *hash, size_t hash_len) } EXPORT_SYMBOL_GPL(is_binary_blacklisted); +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 -EPERM; + return 0; +} + /* * 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");