certs/Makefile

   1 # SPDX-License-Identifier: GPL-2.0
   2 #
   3 # Makefile for the linux kernel signature checking certificates.
   4 #
   5
   6 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
   7 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
   8 ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
   9 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
  10 else
  11 obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
  12 endif
  13
  14 ifeq ($(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 $(objtree)
  22 AFLAGS_system_certificates.o := -I$(srctree)
  23
  24 quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
  25       cmd_extract_certs  = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
  26
  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)$(CONFIG_SYSTEM_TRUSTED_KEYS))
  30 endif # CONFIG_SYSTEM_TRUSTED_KEYRING
  31
  32 clean-files := x509_certificate_list .x509.list
  33
  34 ifeq ($(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 ###############################################################################
  42 ifndef CONFIG_MODULE_SIG_HASH
  43 $(error Could not determine digest type to use from kernel config)
  44 endif
  45
  46 redirect_openssl        = 2>&1
  47 quiet_redirect_openssl  = 2>&1
  48 silent_redirect_openssl = 2>/dev/null
  49
  50 # We do it this way rather than having a boolean option for enabling an
  51 # external private key, because 'make randconfig' might enable such a
  52 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
  53 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
  54 $(obj)/signing_key.pem: $(obj)/x509.genkey
  55         @$(kecho) "###"
  56         @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
  57         @$(kecho) "###"
  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."
  62         @$(kecho) "###"
  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)
  68         @$(kecho) "###"
  69         @$(kecho) "### Key pair generated."
  70         @$(kecho) "###"
  71
  72 $(obj)/x509.genkey:
  73         @$(kecho) Generating X.509 key generation config
  74         @echo  >$@ "[ req ]"
  75         @echo >>$@ "default_bits = 4096"
  76         @echo >>$@ "distinguished_name = req_distinguished_name"
  77         @echo >>$@ "prompt = no"
  78         @echo >>$@ "string_mask = utf8only"
  79         @echo >>$@ "x509_extensions = myexts"
  80         @echo >>$@
  81         @echo >>$@ "[ req_distinguished_name ]"
  82         @echo >>$@ "#O = Unspecified company"
  83         @echo >>$@ "CN = Build time autogenerated kernel key"
  84         @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
  85         @echo >>$@
  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
  92
  93 $(eval $(call config_filename,MODULE_SIG_KEY))
  94
  95 # If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
  96 ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
  97 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
  98 endif
  99
 100 # GCC PR#66871 again.
 101 $(obj)/system_certificates.o: $(obj)/signing_key.x509
 102
 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