certs/Makefile

   1 # SPDX-License-Identifier: GPL-2.0
   2 #
   3 # Makefile for the linux kernel signature checking certificates.
   4 #
   5
   6 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o common.o
   7 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o common.o
   8 obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
   9 ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
  10 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
  11 else
  12 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
  13 endif
  14
  15 ifeq ($(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 $(objtree)
  23 AFLAGS_system_certificates.o := -I$(srctree)
  24
  25 quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
  26       cmd_extract_certs  = scripts/extract-cert $(2) $@
  27
  28 targets += 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)$(CONFIG_SYSTEM_TRUSTED_KEYS))
  31 endif # CONFIG_SYSTEM_TRUSTED_KEYRING
  32
  33 clean-files := x509_certificate_list .x509.list x509_revocation_list
  34
  35 ifeq ($(CONFIG_MODULE_SIG),y)
  36         SIGN_KEY = y
  37 endif
  38
  39 ifeq ($(CONFIG_IMA_APPRAISE_MODSIG),y)
  40 ifeq ($(CONFIG_MODULES),y)
  41         SIGN_KEY = y
  42 endif
  43 endif
  44
  45 ifdef 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 ###############################################################################
  53 ifndef CONFIG_MODULE_SIG_HASH
  54 $(error Could not determine digest type to use from kernel config)
  55 endif
  56
  57 redirect_openssl        = 2>&1
  58 quiet_redirect_openssl  = 2>&1
  59 silent_redirect_openssl = 2>/dev/null
  60 openssl_available       = $(shell openssl help 2>/dev/null && echo yes)
  61
  62 # We do it this way rather than having a boolean option for enabling an
  63 # external private key, because 'make randconfig' might enable such a
  64 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
  65 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
  66
  67 ifeq ($(openssl_available),yes)
  68 X509TEXT=$(shell openssl x509 -in "certs/signing_key.pem" -text 2>/dev/null)
  69 endif
  70
  71 # Support user changing key type
  72 ifdef CONFIG_MODULE_SIG_KEY_TYPE_ECDSA
  73 keytype_openssl = -newkey ec -pkeyopt ec_paramgen_curve:secp384r1
  74 ifeq ($(openssl_available),yes)
  75 $(if $(findstring id-ecPublicKey,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem"))
  76 endif
  77 endif # CONFIG_MODULE_SIG_KEY_TYPE_ECDSA
  78
  79 ifdef CONFIG_MODULE_SIG_KEY_TYPE_RSA
  80 ifeq ($(openssl_available),yes)
  81 $(if $(findstring rsaEncryption,$(X509TEXT)),,$(shell rm -f "certs/signing_key.pem"))
  82 endif
  83 endif # 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"
 123 endif # CONFIG_MODULE_SIG_KEY
 124
 125 $(eval $(call config_filename,MODULE_SIG_KEY))
 126
 127 # If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
 128 ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
 129 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
 130 endif
 131
 132 # GCC PR#66871 again.
 133 $(obj)/system_certificates.o: $(obj)/signing_key.x509
 134
 135 targets += signing_key.x509
 136 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
 137         $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
 138 endif # CONFIG_MODULE_SIG
 139
 140 ifeq ($(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
 146 quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
 147       cmd_extract_certs  = scripts/extract-cert $(2) $@
 148
 149 targets += 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))
 152 endif