4 files changed, 43 insertions, 15 deletions
diff --git a/certs/Makefile b/certs/Makefile
index 88a73b28d254..9486ed924731 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -4,24 +4,22 @@
 #
 
 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
-obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
+obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o blacklist_hashes.o
 obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
-ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),)
 
 $(obj)/blacklist_hashes.o: $(obj)/blacklist_hash_list
 CFLAGS_blacklist_hashes.o := -I $(obj)
 
 quiet_cmd_check_and_copy_blacklist_hash_list = GEN     $@
       cmd_check_and_copy_blacklist_hash_list = \
-	$(AWK) -f $(srctree)/scripts/check-blacklist-hashes.awk $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST) >&2; \
-	cat $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST) > $@
+	$(if $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST), \
+	$(AWK) -f $(srctree)/$(src)/check-blacklist-hashes.awk $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST) >&2; \
+	{ cat $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST); echo $(comma) NULL; } > $@, \
+	echo NULL > $@)
 
 $(obj)/blacklist_hash_list: $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST) FORCE
 	$(call if_changed,check_and_copy_blacklist_hash_list)
-obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
-else
-obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
-endif
+
 targets += blacklist_hash_list
 
 quiet_cmd_extract_certs  = CERT    $@
diff --git a/certs/blacklist_hashes.c b/certs/blacklist_hashes.c
index 86d66fe11348..0c5476abebd9 100644
--- a/certs/blacklist_hashes.c
+++ b/certs/blacklist_hashes.c
@@ -3,5 +3,4 @@
 
 const char __initconst *const blacklist_hashes[] = {
 #include "blacklist_hash_list"
-	, NULL
 };
diff --git a/certs/blacklist_nohashes.c b/certs/blacklist_nohashes.c
deleted file mode 100644
index 753b703ef0ef..000000000000
--- a/certs/blacklist_nohashes.c
+++ /dev/null
@@ -1,6 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include "blacklist.h"
-
-const char __initconst *const blacklist_hashes[] = {
-	NULL
-};
diff --git a/certs/check-blacklist-hashes.awk b/certs/check-blacklist-hashes.awk
new file mode 100755
index 000000000000..107c1d3204d4
--- /dev/null
+++ b/certs/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;
+	}
+}