1 # SPDX-License-Identifier: GPL-2.0
3 # Makefile for the linux kernel signature checking certificates.
6 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
7 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
8 ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
9 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
11 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
14 ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
16 $(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
18 # GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
19 $(obj)/system_certificates.o: $(obj)/x509_certificate_list
21 # Cope with signing_key.x509 existing in $(srctree) not $(objtree)
22 AFLAGS_system_certificates.o := -I$(srctree)
24 quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
25 cmd_extract_certs = scripts/extract-cert $(2) $@
27 targets += x509_certificate_list
28 $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
29 $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
30 endif # CONFIG_SYSTEM_TRUSTED_KEYRING
32 clean-files := x509_certificate_list .x509.list
34 ifeq ($(CONFIG_MODULE_SIG),y)
35 ###############################################################################
37 # If module signing is requested, say by allyesconfig, but a key has not been
38 # supplied, then one will need to be generated to make sure the build does not
39 # fail and that the kernel may be used afterwards.
41 ###############################################################################
42 ifndef CONFIG_MODULE_SIG_HASH
43 $(error Could not determine digest type to use from kernel config)
46 redirect_openssl = 2>&1
47 quiet_redirect_openssl = 2>&1
48 silent_redirect_openssl = 2>/dev/null
50 # We do it this way rather than having a boolean option for enabling an
51 # external private key, because 'make randconfig' might enable such a
52 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
53 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
54 $(obj)/signing_key.pem: $(obj)/x509.genkey
56 @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
58 @$(kecho) "### If this takes a long time, you might wish to run rngd in the"
59 @$(kecho) "### background to keep the supply of entropy topped up. It"
60 @$(kecho) "### needs to be run as root, and uses a hardware random"
61 @$(kecho) "### number generator if one is available."
63 $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
64 -batch -x509 -config $(obj)/x509.genkey \
65 -outform PEM -out $(obj)/signing_key.pem \
66 -keyout $(obj)/signing_key.pem \
67 $($(quiet)redirect_openssl)
69 @$(kecho) "### Key pair generated."
73 @$(kecho) Generating X.509 key generation config
75 @echo >>$@ "default_bits = 4096"
76 @echo >>$@ "distinguished_name = req_distinguished_name"
77 @echo >>$@ "prompt = no"
78 @echo >>$@ "string_mask = utf8only"
79 @echo >>$@ "x509_extensions = myexts"
81 @echo >>$@ "[ req_distinguished_name ]"
82 @echo >>$@ "#O = Unspecified company"
83 @echo >>$@ "CN = Build time autogenerated kernel key"
84 @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
86 @echo >>$@ "[ myexts ]"
87 @echo >>$@ "basicConstraints=critical,CA:FALSE"
88 @echo >>$@ "keyUsage=digitalSignature"
89 @echo >>$@ "subjectKeyIdentifier=hash"
90 @echo >>$@ "authorityKeyIdentifier=keyid"
91 endif # CONFIG_MODULE_SIG_KEY
93 $(eval $(call config_filename,MODULE_SIG_KEY))
95 # If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
96 ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
97 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
100 # GCC PR#66871 again.
101 $(obj)/system_certificates.o: $(obj)/signing_key.x509
103 targets += signing_key.x509
104 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
105 $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
106 endif # CONFIG_MODULE_SIG