1 # SPDX-License-Identifier: GPL-2.0
3 # Makefile for the linux kernel signature checking certificates.
6 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
7 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o common.o
8 obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
9 ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
10 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
12 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
15 ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
17 $(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
19 # GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
20 $(obj)/system_certificates.o: $(obj)/x509_certificate_list
22 # Cope with signing_key.x509 existing in $(srctree) not $(objtree)
23 AFLAGS_system_certificates.o := -I$(srctree)
25 quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
26 cmd_extract_certs = scripts/extract-cert $(2) $@
28 targets += x509_certificate_list
29 $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
30 $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
31 endif # CONFIG_SYSTEM_TRUSTED_KEYRING
33 clean-files := x509_certificate_list .x509.list x509_revocation_list
35 ifeq ($(CONFIG_MODULE_SIG),y)
36 ###############################################################################
38 # If module signing is requested, say by allyesconfig, but a key has not been
39 # supplied, then one will need to be generated to make sure the build does not
40 # fail and that the kernel may be used afterwards.
42 ###############################################################################
43 ifndef CONFIG_MODULE_SIG_HASH
44 $(error Could not determine digest type to use from kernel config)
47 redirect_openssl = 2>&1
48 quiet_redirect_openssl = 2>&1
49 silent_redirect_openssl = 2>/dev/null
50 openssl_available = $(shell openssl help 2>/dev/null && echo yes)
52 # We do it this way rather than having a boolean option for enabling an
53 # external private key, because 'make randconfig' might enable such a
54 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
55 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
57 ifeq ($(openssl_available),yes)
58 X509TEXT=$(shell openssl x509 -in "certs/signing_key.pem" -text 2>/dev/null)
60 $(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem"))
63 $(obj)/signing_key.pem: $(obj)/x509.genkey
65 @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
67 @$(kecho) "### If this takes a long time, you might wish to run rngd in the"
68 @$(kecho) "### background to keep the supply of entropy topped up. It"
69 @$(kecho) "### needs to be run as root, and uses a hardware random"
70 @$(kecho) "### number generator if one is available."
72 $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
73 -batch -x509 -config $(obj)/x509.genkey \
74 -outform PEM -out $(obj)/signing_key.pem \
75 -keyout $(obj)/signing_key.pem \
76 $($(quiet)redirect_openssl)
78 @$(kecho) "### Key pair generated."
82 @$(kecho) Generating X.509 key generation config
84 @echo >>$@ "default_bits = 4096"
85 @echo >>$@ "distinguished_name = req_distinguished_name"
86 @echo >>$@ "prompt = no"
87 @echo >>$@ "string_mask = utf8only"
88 @echo >>$@ "x509_extensions = myexts"
90 @echo >>$@ "[ req_distinguished_name ]"
91 @echo >>$@ "#O = Unspecified company"
92 @echo >>$@ "CN = Build time autogenerated kernel key"
93 @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
95 @echo >>$@ "[ myexts ]"
96 @echo >>$@ "basicConstraints=critical,CA:FALSE"
97 @echo >>$@ "keyUsage=digitalSignature"
98 @echo >>$@ "subjectKeyIdentifier=hash"
99 @echo >>$@ "authorityKeyIdentifier=keyid"
100 endif # CONFIG_MODULE_SIG_KEY
102 $(eval $(call config_filename,MODULE_SIG_KEY))
104 # If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
105 ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
106 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
109 # GCC PR#66871 again.
110 $(obj)/system_certificates.o: $(obj)/signing_key.x509
112 targets += signing_key.x509
113 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
114 $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
115 endif # CONFIG_MODULE_SIG
117 ifeq ($(CONFIG_SYSTEM_REVOCATION_LIST),y)
119 $(eval $(call config_filename,SYSTEM_REVOCATION_KEYS))
121 $(obj)/revocation_certificates.o: $(obj)/x509_revocation_list
123 quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
124 cmd_extract_certs = scripts/extract-cert $(2) $@
126 targets += x509_revocation_list
127 $(obj)/x509_revocation_list: scripts/extract-cert $(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(SYSTEM_REVOCATION_KEYS_FILENAME) FORCE
128 $(call if_changed,extract_certs,$(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_REVOCATION_KEYS))