linux/certs/Makefile
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   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$(error Could not determine digest type to use from kernel config)
  55endif
  56
  57redirect_openssl        = 2>&1
  58quiet_redirect_openssl  = 2>&1
  59silent_redirect_openssl = 2>/dev/null
  60
  61# We do it this way rather than having a boolean option for enabling an
  62# external private key, because 'make randconfig' might enable such a
  63# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
  64ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
  65$(obj)/signing_key.pem: $(obj)/x509.genkey
  66        @$(kecho) "###"
  67        @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
  68        @$(kecho) "###"
  69        @$(kecho) "### If this takes a long time, you might wish to run rngd in the"
  70        @$(kecho) "### background to keep the supply of entropy topped up.  It"
  71        @$(kecho) "### needs to be run as root, and uses a hardware random"
  72        @$(kecho) "### number generator if one is available."
  73        @$(kecho) "###"
  74        $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
  75                -batch -x509 -config $(obj)/x509.genkey \
  76                -outform PEM -out $(obj)/signing_key.pem \
  77                -keyout $(obj)/signing_key.pem \
  78                $($(quiet)redirect_openssl)
  79        @$(kecho) "###"
  80        @$(kecho) "### Key pair generated."
  81        @$(kecho) "###"
  82
  83$(obj)/x509.genkey:
  84        @$(kecho) Generating X.509 key generation config
  85        @echo  >$@ "[ req ]"
  86        @echo >>$@ "default_bits = 4096"
  87        @echo >>$@ "distinguished_name = req_distinguished_name"
  88        @echo >>$@ "prompt = no"
  89        @echo >>$@ "string_mask = utf8only"
  90        @echo >>$@ "x509_extensions = myexts"
  91        @echo >>$@
  92        @echo >>$@ "[ req_distinguished_name ]"
  93        @echo >>$@ "#O = Unspecified company"
  94        @echo >>$@ "CN = Build time autogenerated kernel key"
  95        @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
  96        @echo >>$@
  97        @echo >>$@ "[ myexts ]"
  98        @echo >>$@ "basicConstraints=critical,CA:FALSE"
  99        @echo >>$@ "keyUsage=digitalSignature"
 100        @echo >>$@ "subjectKeyIdentifier=hash"
 101        @echo >>$@ "authorityKeyIdentifier=keyid"
 102endif # CONFIG_MODULE_SIG_KEY
 103
 104$(eval $(call config_filename,MODULE_SIG_KEY))
 105
 106# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
 107ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
 108X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
 109endif
 110
 111# GCC PR#66871 again.
 112$(obj)/system_certificates.o: $(obj)/signing_key.x509
 113
 114targets += signing_key.x509
 115$(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
 116        $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
 117endif # CONFIG_MODULE_SIG
 118
 119ifeq ($(CONFIG_SYSTEM_REVOCATION_LIST),y)
 120
 121$(eval $(call config_filename,SYSTEM_REVOCATION_KEYS))
 122
 123$(obj)/revocation_certificates.o: $(obj)/x509_revocation_list
 124
 125quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
 126      cmd_extract_certs  = scripts/extract-cert $(2) $@
 127
 128targets += x509_revocation_list
 129$(obj)/x509_revocation_list: scripts/extract-cert $(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(SYSTEM_REVOCATION_KEYS_FILENAME) FORCE
 130        $(call if_changed,extract_certs,$(SYSTEM_REVOCATION_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_REVOCATION_KEYS))
 131endif
 132