1# 2# Makefile for the linux kernel signature checking certificates. 3# 4 5obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o 6 7ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y) 8 9$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS)) 10 11# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871) 12$(obj)/system_certificates.o: $(obj)/x509_certificate_list 13 14# Cope with signing_key.x509 existing in $(srctree) not $(objtree) 15AFLAGS_system_certificates.o := -I$(srctree) 16 17quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2)) 18 cmd_extract_certs = scripts/extract-cert $(2) $@ || ( rm $@; exit 1) 19 20targets += x509_certificate_list 21$(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE 22 $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS)) 23endif 24 25clean-files := x509_certificate_list .x509.list 26 27ifeq ($(CONFIG_MODULE_SIG),y) 28############################################################################### 29# 30# If module signing is requested, say by allyesconfig, but a key has not been 31# supplied, then one will need to be generated to make sure the build does not 32# fail and that the kernel may be used afterwards. 33# 34############################################################################### 35ifndef CONFIG_MODULE_SIG_HASH 36$(error Could not determine digest type to use from kernel config) 37endif 38 39# We do it this way rather than having a boolean option for enabling an 40# external private key, because 'make randconfig' might enable such a 41# boolean option and we unfortunately can't make it depend on !RANDCONFIG. 42ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem") 43$(obj)/signing_key.pem: $(obj)/x509.genkey 44 @echo "###" 45 @echo "### Now generating an X.509 key pair to be used for signing modules." 46 @echo "###" 47 @echo "### If this takes a long time, you might wish to run rngd in the" 48 @echo "### background to keep the supply of entropy topped up. It" 49 @echo "### needs to be run as root, and uses a hardware random" 50 @echo "### number generator if one is available." 51 @echo "###" 52 openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \ 53 -batch -x509 -config $(obj)/x509.genkey \ 54 -outform PEM -out $(obj)/signing_key.pem \ 55 -keyout $(obj)/signing_key.pem 2>&1 56 @echo "###" 57 @echo "### Key pair generated." 58 @echo "###" 59 60$(obj)/x509.genkey: 61 @echo Generating X.509 key generation config 62 @echo >$@ "[ req ]" 63 @echo >>$@ "default_bits = 4096" 64 @echo >>$@ "distinguished_name = req_distinguished_name" 65 @echo >>$@ "prompt = no" 66 @echo >>$@ "string_mask = utf8only" 67 @echo >>$@ "x509_extensions = myexts" 68 @echo >>$@ 69 @echo >>$@ "[ req_distinguished_name ]" 70 @echo >>$@ "#O = Unspecified company" 71 @echo >>$@ "CN = Build time autogenerated kernel key" 72 @echo >>$@ "#emailAddress = unspecified.user@unspecified.company" 73 @echo >>$@ 74 @echo >>$@ "[ myexts ]" 75 @echo >>$@ "basicConstraints=critical,CA:FALSE" 76 @echo >>$@ "keyUsage=digitalSignature" 77 @echo >>$@ "subjectKeyIdentifier=hash" 78 @echo >>$@ "authorityKeyIdentifier=keyid" 79endif 80 81$(eval $(call config_filename,MODULE_SIG_KEY)) 82 83# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it 84ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME))) 85X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME) 86endif 87 88# GCC PR#66871 again. 89$(obj)/system_certificates.o: $(obj)/signing_key.x509 90 91targets += signing_key.x509 92$(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE 93 $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY)) 94endif 95