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* [PATCH v4 00/10] Enable root to update the blacklist keyring
@ 2021-01-21 15:55 Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 01/10] tools/certs: Add print-cert-tbs-hash.sh Mickaël Salaün
                   ` (10 more replies)
  0 siblings, 11 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

This fourth patch series mainly reorder patches and add more
documentation as requested by Jarkko.  This series is based on
v5.11-rc4.

The goal of these patches is to add a new configuration option to enable the
root user to load signed keys in the blacklist keyring.  This keyring is useful
to "untrust" certificates or files.  Enabling to safely update this keyring
without recompiling the kernel makes it more usable.

Previous patch series:
https://lore.kernel.org/lkml/20210114151909.2344974-1-mic@digikod.net/

Regards,

Alex Shi (1):
  certs/blacklist: fix kernel doc interface issue

David Howells (1):
  certs: Fix blacklist flag type confusion

Mickaël Salaün (8):
  tools/certs: Add print-cert-tbs-hash.sh
  certs: Check that builtin blacklist hashes are valid
  certs: Fix blacklisted hexadecimal hash string check
  certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID
  certs: Make blacklist_vet_description() more strict
  certs: Factor out the blacklist hash creation
  PKCS#7: Fix missing include
  certs: Allow root user to append signed hashes to the blacklist
    keyring

 MAINTAINERS                                   |   2 +
 certs/.gitignore                              |   1 +
 certs/Kconfig                                 |  17 +-
 certs/Makefile                                |  15 +-
 certs/blacklist.c                             | 217 ++++++++++++++----
 certs/system_keyring.c                        |   5 +-
 crypto/asymmetric_keys/x509_public_key.c      |   3 +-
 include/keys/system_keyring.h                 |  14 +-
 include/linux/key.h                           |   1 +
 include/linux/verification.h                  |   2 +
 scripts/check-blacklist-hashes.awk            |  37 +++
 security/integrity/ima/ima_mok.c              |   4 +-
 .../platform_certs/keyring_handler.c          |  26 +--
 security/keys/key.c                           |   2 +
 tools/certs/print-cert-tbs-hash.sh            |  91 ++++++++
 15 files changed, 350 insertions(+), 87 deletions(-)
 create mode 100755 scripts/check-blacklist-hashes.awk
 create mode 100755 tools/certs/print-cert-tbs-hash.sh


base-commit: 19c329f6808995b142b3966301f217c831e7cf31
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 01/10] tools/certs: Add print-cert-tbs-hash.sh
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 02/10] certs: Check that builtin blacklist hashes are valid Mickaël Salaün
                   ` (9 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

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

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 <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
---

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 <miguel.ojeda.sandonis@gmail.com>
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 <mic@linux.microsoft.com>
+#
+# 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: ${BASENAME} <certificate>" >&2
+	exit 1
+fi
+
+# Checks that it is indeed a certificate (PEM or DER encoded) and exclude the
+# optional PEM text header.
+if ! PEM="$(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}'
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 02/10] certs: Check that builtin blacklist hashes are valid
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 01/10] tools/certs: Add print-cert-tbs-hash.sh Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 03/10] certs: Fix blacklisted hexadecimal hash string check Mickaël Salaün
                   ` (8 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

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

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

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 "<hash>", "<hash>", ... .  This will be included into a C
-	  wrapper to incorporate the list into the kernel.  Each <hash> should
-	  be a string of hex digits.
+	  wrapper to incorporate the list into the kernel.  Each <hash> 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 <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


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 03/10] certs: Fix blacklisted hexadecimal hash string check
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 01/10] tools/certs: Add print-cert-tbs-hash.sh Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 02/10] certs: Check that builtin blacklist hashes are valid Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 04/10] certs: Fix blacklist flag type confusion Mickaël Salaün
                   ` (7 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module,
	Ben Boeckel

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

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 <dwmw2@infradead.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Ben Boeckel <mathstuf@gmail.com>
---

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++;
 	}
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 04/10] certs: Fix blacklist flag type confusion
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (2 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 03/10] certs: Fix blacklisted hexadecimal hash string check Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 05/10] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Mickaël Salaün
                   ` (6 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module, Mimi Zohar

From: David Howells <dhowells@redhat.com>

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 <zohar@linux.vnet.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Reported-by: Mickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: David Howells <dhowells@redhat.com>
[mic@linux.microsoft.com: Fix argument bit-ORing in ima_mok_init() and
extend commit description]
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
---

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;
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 05/10] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (3 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 04/10] certs: Fix blacklist flag type confusion Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 06/10] certs: Make blacklist_vet_description() more strict Mickaël Salaün
                   ` (5 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

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

Use GLOBAL_ROOT_UID and GLOBAL_ROOT_GID definitions, and add appropriate
include files.

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

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 <linux/ctype.h>
 #include <linux/err.h>
 #include <linux/seq_file.h>
+#include <linux/uidgid.h>
 #include <keys/system_keyring.h>
 #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 <linux/cred.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/uidgid.h>
 #include <linux/verification.h>
 #include <keys/asymmetric-type.h>
 #include <keys/system_keyring.h>
@@ -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),
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 06/10] certs: Make blacklist_vet_description() more strict
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (4 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 05/10] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 07/10] certs/blacklist: fix kernel doc interface issue Mickaël Salaün
                   ` (4 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

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

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 <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:
* 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 <keys/system_keyring.h>
 #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;
 }
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 07/10] certs/blacklist: fix kernel doc interface issue
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (5 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 06/10] certs: Make blacklist_vet_description() more strict Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 08/10] certs: Factor out the blacklist hash creation Mickaël Salaün
                   ` (3 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module, Alex Shi,
	Ben Boeckel

From: Alex Shi <alex.shi@linux.alibaba.com>

certs/blacklist.c:84: warning: Function parameter or member 'hash' not
described in 'mark_hash_blacklisted'

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: keyrings@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Ben Boeckel <mathstuf@gmail.com>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
---

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)
 {
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 08/10] certs: Factor out the blacklist hash creation
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (6 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 07/10] certs/blacklist: fix kernel doc interface issue Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 09/10] PKCS#7: Fix missing include Mickaël Salaün
                   ` (2 subsequent siblings)
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

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

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 <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
---

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 <linux/key.h>
 
+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);
 }
 
 /*
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 09/10] PKCS#7: Fix missing include
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (7 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 08/10] certs: Factor out the blacklist hash creation Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-21 15:55 ` [PATCH v4 10/10] certs: Allow root user to append signed hashes to the blacklist keyring Mickaël Salaün
  2021-01-28 16:52 ` [PATCH v4 00/10] Enable root to update " David Howells
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module,
	Ben Boeckel

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

Add missing linux/types.h for size_t.

[DH: Changed from stddef.h]

Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Ben Boeckel <mathstuf@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
---

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 <linux/types.h>
+
 /*
  * Indicate that both builtin trusted keys and secondary trusted keys
  * should be used.
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH v4 10/10] certs: Allow root user to append signed hashes to the blacklist keyring
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (8 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 09/10] PKCS#7: Fix missing include Mickaël Salaün
@ 2021-01-21 15:55 ` Mickaël Salaün
  2021-01-28 16:52 ` [PATCH v4 00/10] Enable root to update " David Howells
  10 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-21 15:55 UTC (permalink / raw)
  To: David Howells, David Woodhouse, Jarkko Sakkinen
  Cc: Mickaël Salaün, David S . Miller, Herbert Xu,
	James Morris, Mickaël Salaün, Mimi Zohar,
	Serge E . Hallyn, Tyler Hicks, keyrings, linux-crypto,
	linux-integrity, linux-kernel, linux-security-module

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

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 <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
---

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 <linux/err.h>
 #include <linux/seq_file.h>
 #include <linux/uidgid.h>
+#include <linux/verification.h>
 #include <keys/system_keyring.h>
 #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");
 
-- 
2.30.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v4 00/10] Enable root to update the blacklist keyring
  2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
                   ` (9 preceding siblings ...)
  2021-01-21 15:55 ` [PATCH v4 10/10] certs: Allow root user to append signed hashes to the blacklist keyring Mickaël Salaün
@ 2021-01-28 16:52 ` David Howells
  2021-01-28 17:38   ` Mickaël Salaün
  2021-01-30 19:39   ` Jarkko Sakkinen
  10 siblings, 2 replies; 15+ messages in thread
From: David Howells @ 2021-01-28 16:52 UTC (permalink / raw)
  To: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?=
  Cc: dhowells, David Woodhouse, Jarkko Sakkinen, David S . Miller,
	Herbert Xu, James Morris, =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?=,
	Mimi Zohar, Serge E . Hallyn, Tyler Hicks, keyrings,
	linux-crypto, linux-integrity, linux-kernel,
	linux-security-module


Hi Mickaël,

I could pull your patches (unless Jarkko wants to), but can you please drop
the patches that are also in my keys-misc branch lest one or other (or both)
of our branches get dropped in the next merge window due to conflicts?

Ideally, can you base your branch on my keys-misc branch?

Thanks,
David


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v4 00/10] Enable root to update the blacklist keyring
  2021-01-28 16:52 ` [PATCH v4 00/10] Enable root to update " David Howells
@ 2021-01-28 17:38   ` Mickaël Salaün
  2021-01-28 18:00     ` Mickaël Salaün
  2021-01-30 19:39   ` Jarkko Sakkinen
  1 sibling, 1 reply; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-28 17:38 UTC (permalink / raw)
  To: David Howells, Jarkko Sakkinen
  Cc: David Woodhouse, David S . Miller, Herbert Xu, James Morris,
	Mickaël Salaün, Mimi Zohar, Serge E . Hallyn,
	Tyler Hicks, keyrings, linux-crypto, linux-integrity,
	linux-kernel, linux-security-module



On 28/01/2021 17:52, David Howells wrote:
> 
> Hi Mickaël,
Hi David,

> 
> I could pull your patches (unless Jarkko wants to), but can you please drop
> the patches that are also in my keys-misc branch lest one or other (or both)
> of our branches get dropped in the next merge window due to conflicts?
> 
> Ideally, can you base your branch on my keys-misc branch?

Sure, I'm rebasing and testing a new patch series.

> 
> Thanks,
> David
> 

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v4 00/10] Enable root to update the blacklist keyring
  2021-01-28 17:38   ` Mickaël Salaün
@ 2021-01-28 18:00     ` Mickaël Salaün
  0 siblings, 0 replies; 15+ messages in thread
From: Mickaël Salaün @ 2021-01-28 18:00 UTC (permalink / raw)
  To: David Howells, Jarkko Sakkinen
  Cc: David Woodhouse, David S . Miller, Herbert Xu, James Morris,
	Mickaël Salaün, Mimi Zohar, Serge E . Hallyn,
	Tyler Hicks, keyrings, linux-crypto, linux-integrity,
	linux-kernel, linux-security-module

I noticed that commits in your branch are not up to date with latest
Jarkoo reviews on my patches (see changes since v2). There is no
conflict if you replace conflicting patches from your branch by patches
from this series. Could you replace your duplicate commits with this
patch series?


On 28/01/2021 18:38, Mickaël Salaün wrote:
> 
> 
> On 28/01/2021 17:52, David Howells wrote:
>>
>> Hi Mickaël,
> Hi David,
> 
>>
>> I could pull your patches (unless Jarkko wants to), but can you please drop
>> the patches that are also in my keys-misc branch lest one or other (or both)
>> of our branches get dropped in the next merge window due to conflicts?
>>
>> Ideally, can you base your branch on my keys-misc branch?
> 
> Sure, I'm rebasing and testing a new patch series.
> 
>>
>> Thanks,
>> David
>>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v4 00/10] Enable root to update the blacklist keyring
  2021-01-28 16:52 ` [PATCH v4 00/10] Enable root to update " David Howells
  2021-01-28 17:38   ` Mickaël Salaün
@ 2021-01-30 19:39   ` Jarkko Sakkinen
  1 sibling, 0 replies; 15+ messages in thread
From: Jarkko Sakkinen @ 2021-01-30 19:39 UTC (permalink / raw)
  To: David Howells, Mickaël Salaün
  Cc: David Woodhouse, David S . Miller, Herbert Xu, James Morris,
	Mickaël Salaün, Mimi Zohar, Serge E . Hallyn,
	Tyler Hicks, keyrings, linux-crypto, linux-integrity,
	linux-kernel, linux-security-module

On Thu, 2021-01-28 at 16:52 +0000, David Howells wrote:
> 
> Hi Mickaël,
> 
> I could pull your patches (unless Jarkko wants to), but can you please drop
> the patches that are also in my keys-misc branch lest one or other (or both)
> of our branches get dropped in the next merge window due to conflicts?
> 
> Ideally, can you base your branch on my keys-misc branch?

David, please pull :-)

If possible add to all:

Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

Was a chaotic week. My test environment was broken until Wed because
of issues with BuildRoot (that I reported and BR devs were able to
reproduce related to LINUX_OVERRIDE_SRCDIR).

> Thanks,
> David

/Jarkko

^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, back to index

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-21 15:55 [PATCH v4 00/10] Enable root to update the blacklist keyring Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 01/10] tools/certs: Add print-cert-tbs-hash.sh Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 02/10] certs: Check that builtin blacklist hashes are valid Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 03/10] certs: Fix blacklisted hexadecimal hash string check Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 04/10] certs: Fix blacklist flag type confusion Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 05/10] certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 06/10] certs: Make blacklist_vet_description() more strict Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 07/10] certs/blacklist: fix kernel doc interface issue Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 08/10] certs: Factor out the blacklist hash creation Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 09/10] PKCS#7: Fix missing include Mickaël Salaün
2021-01-21 15:55 ` [PATCH v4 10/10] certs: Allow root user to append signed hashes to the blacklist keyring Mickaël Salaün
2021-01-28 16:52 ` [PATCH v4 00/10] Enable root to update " David Howells
2021-01-28 17:38   ` Mickaël Salaün
2021-01-28 18:00     ` Mickaël Salaün
2021-01-30 19:39   ` Jarkko Sakkinen

Keyrings Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/keyrings/0 keyrings/git/0.git

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