certs/Makefile

   1 #
   2 # Makefile for the linux kernel signature checking certificates.
   3 #
   4
   5 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
   6
   7 ifeq ($(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 $(objtree)
  15 AFLAGS_system_certificates.o := -I$(srctree)
  16
  17 quiet_cmd_extract_certs  = EXTRACT_CERTS   $(patsubst "%",%,$(2))
  18       cmd_extract_certs  = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
  19
  20 targets += 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)$(CONFIG_SYSTEM_TRUSTED_KEYS))
  23 endif
  24
  25 clean-files := x509_certificate_list .x509.list
  26
  27 ifeq ($(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 ###############################################################################
  35 ifndef CONFIG_MODULE_SIG_HASH
  36 $(error Could not determine digest type to use from kernel config)
  37 endif
  38
  39 redirect_openssl        = 2>&1
  40 quiet_redirect_openssl  = 2>&1
  41 silent_redirect_openssl = 2>/dev/null
  42
  43 # We do it this way rather than having a boolean option for enabling an
  44 # external private key, because 'make randconfig' might enable such a
  45 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
  46 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
  47 $(obj)/signing_key.pem: $(obj)/x509.genkey
  48         @$(kecho) "###"
  49         @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
  50         @$(kecho) "###"
  51         @$(kecho) "### If this takes a long time, you might wish to run rngd in the"
  52         @$(kecho) "### background to keep the supply of entropy topped up.  It"
  53         @$(kecho) "### needs to be run as root, and uses a hardware random"
  54         @$(kecho) "### number generator if one is available."
  55         @$(kecho) "###"
  56         $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
  57                 -batch -x509 -config $(obj)/x509.genkey \
  58                 -outform PEM -out $(obj)/signing_key.pem \
  59                 -keyout $(obj)/signing_key.pem \
  60                 $($(quiet)redirect_openssl)
  61         @$(kecho) "###"
  62         @$(kecho) "### Key pair generated."
  63         @$(kecho) "###"
  64
  65 $(obj)/x509.genkey:
  66         @$(kecho) Generating X.509 key generation config
  67         @echo  >$@ "[ req ]"
  68         @echo >>$@ "default_bits = 4096"
  69         @echo >>$@ "distinguished_name = req_distinguished_name"
  70         @echo >>$@ "prompt = no"
  71         @echo >>$@ "string_mask = utf8only"
  72         @echo >>$@ "x509_extensions = myexts"
  73         @echo >>$@
  74         @echo >>$@ "[ req_distinguished_name ]"
  75         @echo >>$@ "#O = Unspecified company"
  76         @echo >>$@ "CN = Build time autogenerated kernel key"
  77         @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
  78         @echo >>$@
  79         @echo >>$@ "[ myexts ]"
  80         @echo >>$@ "basicConstraints=critical,CA:FALSE"
  81         @echo >>$@ "keyUsage=digitalSignature"
  82         @echo >>$@ "subjectKeyIdentifier=hash"
  83         @echo >>$@ "authorityKeyIdentifier=keyid"
  84 endif
  85
  86 $(eval $(call config_filename,MODULE_SIG_KEY))
  87
  88 # If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
  89 ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
  90 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
  91 endif
  92
  93 # GCC PR#66871 again.
  94 $(obj)/system_certificates.o: $(obj)/signing_key.x509
  95
  96 targets += signing_key.x509
  97 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
  98         $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
  99 endif