All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Mickaël Salaün" <mic@digikod.net>
To: David Howells <dhowells@redhat.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Jarkko Sakkinen <jarkko@kernel.org>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"David S . Miller" <davem@davemloft.net>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"James Morris" <jmorris@namei.org>,
	"Mickaël Salaün" <mic@linux.microsoft.com>,
	"Mimi Zohar" <zohar@linux.ibm.com>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	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 v3 08/10] certs: Check that builtin blacklist hashes are valid
Date: Thu, 14 Jan 2021 16:19:07 +0100	[thread overview]
Message-ID: <20210114151909.2344974-9-mic@digikod.net> (raw)
In-Reply-To: <20210114151909.2344974-1-mic@digikod.net>

From: Mickaël Salaün <mic@linux.microsoft.com>

Add and use a check-blacklist-hashes.awk script to make sure that the
builtin blacklist hashes will be approved by the run time blacklist
description checks.  This is useful to debug invalid hash formats, and
it make sure that previous hashes which could have been loaded in the
kernel (but ignored) are now noticed and deal with by the user.

Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
---

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/Makefile                     | 15 +++++++++++-
 scripts/check-blacklist-hashes.awk | 37 ++++++++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100755 scripts/check-blacklist-hashes.awk

diff --git a/MAINTAINERS b/MAINTAINERS
index cc1e6a5ee6e6..bda31ccbfad0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4120,6 +4120,7 @@ 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
 
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/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 <mic@linux.microsoft.com>
+#
+# 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;
+	}
+}
-- 
2.30.0


  parent reply	other threads:[~2021-01-14 15:20 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 15:18 [PATCH v3 00/10] Enable root to update the blacklist keyring Mickaël Salaün
2021-01-14 15:19 ` [PATCH v3 01/10] certs/blacklist: fix kernel doc interface issue Mickaël Salaün
2021-01-20  3:39   ` Jarkko Sakkinen
2021-01-14 15:19 ` [PATCH v3 02/10] certs: Fix blacklisted hexadecimal hash string check Mickaël Salaün
2021-01-20  3:43   ` Jarkko Sakkinen
2021-01-20 11:12     ` Mickaël Salaün
2021-01-20 23:44       ` Jarkko Sakkinen
2021-01-14 15:19 ` [PATCH v3 03/10] PKCS#7: Fix missing include Mickaël Salaün
2021-01-20  3:44   ` Jarkko Sakkinen
2021-01-14 15:19 ` [PATCH v3 04/10] certs: Fix blacklist flag type confusion Mickaël Salaün
2021-01-20  3:55   ` Jarkko Sakkinen
2021-01-20 11:15     ` Mickaël Salaün
2021-01-20 23:45       ` Jarkko Sakkinen
2021-01-14 15:19 ` [PATCH v3 05/10] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Mickaël Salaün
2021-01-20  5:15   ` Jarkko Sakkinen
2021-01-20 11:17     ` Mickaël Salaün
2021-01-20 23:48       ` Jarkko Sakkinen
2021-01-14 15:19 ` [PATCH v3 06/10] certs: Make blacklist_vet_description() more strict Mickaël Salaün
2021-01-20  4:16   ` Jarkko Sakkinen
2021-01-20 11:23     ` Mickaël Salaün
2021-01-14 15:19 ` [PATCH v3 07/10] certs: Factor out the blacklist hash creation Mickaël Salaün
2021-01-14 15:19 ` Mickaël Salaün [this message]
2021-01-20  5:19   ` [PATCH v3 08/10] certs: Check that builtin blacklist hashes are valid Jarkko Sakkinen
2021-01-20 11:57     ` Mickaël Salaün
2021-01-20 23:53       ` Jarkko Sakkinen
2021-01-21  9:18         ` Mickaël Salaün
2021-01-21 15:21           ` Jarkko Sakkinen
2021-01-14 15:19 ` [PATCH v3 09/10] certs: Allow root user to append signed hashes to the blacklist keyring Mickaël Salaün
2021-01-15 13:06   ` Mimi Zohar
2021-01-20  5:23   ` Jarkko Sakkinen
2021-01-20 11:24     ` Mickaël Salaün
2021-01-14 15:19 ` [PATCH v3 10/10] tools/certs: Add print-cert-tbs-hash.sh Mickaël Salaün
2021-01-15  9:28 ` [PATCH v3 00/10] Enable root to update the blacklist keyring Jarkko Sakkinen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210114151909.2344974-9-mic@digikod.net \
    --to=mic@digikod.net \
    --cc=davem@davemloft.net \
    --cc=dhowells@redhat.com \
    --cc=dwmw2@infradead.org \
    --cc=herbert@gondor.apana.org.au \
    --cc=jarkko@kernel.org \
    --cc=jmorris@namei.org \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=mic@linux.microsoft.com \
    --cc=serge@hallyn.com \
    --cc=zohar@linux.ibm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.