xref: /openbmc/linux/certs/Makefile (revision 6219b20e) 
1# SPDX-License-Identifier: GPL-2.0
2#
3# Makefile for the linux kernel signature checking certificates.
4#
5
6obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
7obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o common.o
8obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
9ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
10obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
11else
12obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
13endif
14
15ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
16
17$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
18
19# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
20$(obj)/system_certificates.o: $(obj)/x509_certificate_list
21
22# Cope with signing_key.x509 existing in $(srctree) not $(objtree)
23AFLAGS_system_certificates.o := -I$(srctree)
24
25quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
26      cmd_extract_certs  = scripts/extract-cert $(2) $@
27
28targets += x509_certificate_list
29$(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)$(CONFIG_SYSTEM_TRUSTED_KEYS))
31endif # CONFIG_SYSTEM_TRUSTED_KEYRING
32
33clean-files := x509_certificate_list .x509.list x509_revocation_list
34
35ifeq ($(CONFIG_MODULE_SIG),y)
36	SIGN_KEY = y
37endif
38
39ifeq ($(CONFIG_IMA_APPRAISE_MODSIG),y)
40ifeq ($(CONFIG_MODULES),y)
41	SIGN_KEY = y
42endif
43endif
44
45ifdef SIGN_KEY
46###############################################################################
47#
48# If module signing is requested, say by allyesconfig, but a key has not been
49# supplied, then one will need to be generated to make sure the build does not
50# fail and that the kernel may be used afterwards.
51#
52###############################################################################
53ifndef CONFIG_MODULE_SIG_HASH
54$(error Could not determine digest type to use from kernel config)
55endif
56
57redirect_openssl	= 2>&1
58quiet_redirect_openssl	= 2>&1
59silent_redirect_openssl = 2>/dev/null
60openssl_available       = $(shell openssl help 2>/dev/null && echo yes)
61
62# We do it this way rather than having a boolean option for enabling an
63# external private key, because 'make randconfig' might enable such a
64# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
65ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
66
67ifeq ($(openssl_available),yes)
68X509TEXT=$(shell openssl x509 -in "certs/signing_key.pem" -text 2>/dev/null)
69endif
70
71# Support user changing key type
72ifdef CONFIG_MODULE_SIG_KEY_TYPE_ECDSA
73keytype_openssl = -newkey ec -pkeyopt ec_paramgen_curve:secp384r1
74ifeq ($(openssl_available),yes)
75$(if $(findstring id-ecPublicKey,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem"))
76endif
77endif # CONFIG_MODULE_SIG_KEY_TYPE_ECDSA
78
79ifdef CONFIG_MODULE_SIG_KEY_TYPE_RSA
80ifeq ($(openssl_available),yes)
81$(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem"))
82endif
83endif # CONFIG_MODULE_SIG_KEY_TYPE_RSA
84
85$(obj)/signing_key.pem: $(obj)/x509.genkey
86	@$(kecho) "###"
87	@$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
88	@$(kecho) "###"
89	@$(kecho) "### If this takes a long time, you might wish to run rngd in the"
90	@$(kecho) "### background to keep the supply of entropy topped up.  It"
91	@$(kecho) "### needs to be run as root, and uses a hardware random"
92	@$(kecho) "### number generator if one is available."
93	@$(kecho) "###"
94	$(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
95		-batch -x509 -config $(obj)/x509.genkey \
96		-outform PEM -out $(obj)/signing_key.pem \
97		-keyout $(obj)/signing_key.pem \
98		$(keytype_openssl) \
99		$($(quiet)redirect_openssl)
100	@$(kecho) "###"
101	@$(kecho) "### Key pair generated."
102	@$(kecho) "###"
103
104$(obj)/x509.genkey:
105	@$(kecho) Generating X.509 key generation config
106	@echo  >$@ "[ req ]"
107	@echo >>$@ "default_bits = 4096"
108	@echo >>$@ "distinguished_name = req_distinguished_name"
109	@echo >>$@ "prompt = no"
110	@echo >>$@ "string_mask = utf8only"
111	@echo >>$@ "x509_extensions = myexts"
112	@echo >>$@
113	@echo >>$@ "[ req_distinguished_name ]"
114	@echo >>$@ "#O = Unspecified company"
115	@echo >>$@ "CN = Build time autogenerated kernel key"
116	@echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
117	@echo >>$@
118	@echo >>$@ "[ myexts ]"
119	@echo >>$@ "basicConstraints=critical,CA:FALSE"
120	@echo >>$@ "keyUsage=digitalSignature"
121	@echo >>$@ "subjectKeyIdentifier=hash"
122	@echo >>$@ "authorityKeyIdentifier=keyid"
123endif # CONFIG_MODULE_SIG_KEY
124
125$(eval $(call config_filename,MODULE_SIG_KEY))
126
127# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
128ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
129X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
130endif
131
132# GCC PR#66871 again.
133$(obj)/system_certificates.o: $(obj)/signing_key.x509
134
135targets += signing_key.x509
136$(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
137	$(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
138endif # CONFIG_MODULE_SIG
139
140ifeq ($(CONFIG_SYSTEM_REVOCATION_LIST),y)
141
142$(eval $(call config_filename,SYSTEM_REVOCATION_KEYS))
143
144$(obj)/revocation_certificates.o: $(obj)/x509_revocation_list
145
146quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
147      cmd_extract_certs  = scripts/extract-cert $(2) $@
148
149targets += x509_revocation_list
150$(obj)/x509_revocation_list: scripts/extract-cert $(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(SYSTEM_REVOCATION_KEYS_FILENAME) FORCE
151	$(call if_changed,extract_certs,$(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_REVOCATION_KEYS))
152endif
153