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 8ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"") 9obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o 10else 11obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o 12endif 13 14ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y) 15 16$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS)) 17 18# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871) 19$(obj)/system_certificates.o: $(obj)/x509_certificate_list 20 21# Cope with signing_key.x509 existing in $(srctree) not $(objtree) 22AFLAGS_system_certificates.o := -I$(srctree) 23 24quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2)) 25 cmd_extract_certs = scripts/extract-cert $(2) $@ 26 27targets += x509_certificate_list 28$(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)$(CONFIG_SYSTEM_TRUSTED_KEYS)) 30endif # CONFIG_SYSTEM_TRUSTED_KEYRING 31 32clean-files := x509_certificate_list .x509.list 33 34ifeq ($(CONFIG_MODULE_SIG),y) 35############################################################################### 36# 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. 40# 41############################################################################### 42ifndef CONFIG_MODULE_SIG_HASH 43$(error Could not determine digest type to use from kernel config) 44endif 45 46redirect_openssl = 2>&1 47quiet_redirect_openssl = 2>&1 48silent_redirect_openssl = 2>/dev/null 49openssl_available = $(shell openssl help 2>/dev/null && echo yes) 50 51# We do it this way rather than having a boolean option for enabling an 52# external private key, because 'make randconfig' might enable such a 53# boolean option and we unfortunately can't make it depend on !RANDCONFIG. 54ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem") 55 56ifeq ($(openssl_available),yes) 57X509TEXT=$(shell openssl x509 -in "certs/signing_key.pem" -text 2>/dev/null) 58 59$(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem")) 60endif 61 62$(obj)/signing_key.pem: $(obj)/x509.genkey 63 @$(kecho) "###" 64 @$(kecho) "### Now generating an X.509 key pair to be used for signing modules." 65 @$(kecho) "###" 66 @$(kecho) "### If this takes a long time, you might wish to run rngd in the" 67 @$(kecho) "### background to keep the supply of entropy topped up. It" 68 @$(kecho) "### needs to be run as root, and uses a hardware random" 69 @$(kecho) "### number generator if one is available." 70 @$(kecho) "###" 71 $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \ 72 -batch -x509 -config $(obj)/x509.genkey \ 73 -outform PEM -out $(obj)/signing_key.pem \ 74 -keyout $(obj)/signing_key.pem \ 75 $($(quiet)redirect_openssl) 76 @$(kecho) "###" 77 @$(kecho) "### Key pair generated." 78 @$(kecho) "###" 79 80$(obj)/x509.genkey: 81 @$(kecho) Generating X.509 key generation config 82 @echo >$@ "[ req ]" 83 @echo >>$@ "default_bits = 4096" 84 @echo >>$@ "distinguished_name = req_distinguished_name" 85 @echo >>$@ "prompt = no" 86 @echo >>$@ "string_mask = utf8only" 87 @echo >>$@ "x509_extensions = myexts" 88 @echo >>$@ 89 @echo >>$@ "[ req_distinguished_name ]" 90 @echo >>$@ "#O = Unspecified company" 91 @echo >>$@ "CN = Build time autogenerated kernel key" 92 @echo >>$@ "#emailAddress = unspecified.user@unspecified.company" 93 @echo >>$@ 94 @echo >>$@ "[ myexts ]" 95 @echo >>$@ "basicConstraints=critical,CA:FALSE" 96 @echo >>$@ "keyUsage=digitalSignature" 97 @echo >>$@ "subjectKeyIdentifier=hash" 98 @echo >>$@ "authorityKeyIdentifier=keyid" 99endif # CONFIG_MODULE_SIG_KEY 100 101$(eval $(call config_filename,MODULE_SIG_KEY)) 102 103# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it 104ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME))) 105X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME) 106endif 107 108# GCC PR#66871 again. 109$(obj)/system_certificates.o: $(obj)/signing_key.x509 110 111targets += signing_key.x509 112$(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE 113 $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY)) 114endif # CONFIG_MODULE_SIG 115