734114f878
Add the following:
(1) A new system keyring that is used to store information about
blacklisted certificates and signatures.
(2) A new key type (called 'blacklist') that is used to store a
blacklisted hash in its description as a hex string. The key accepts
no payload.
(3) The ability to configure a list of blacklisted hashes into the kernel
at build time. This is done by setting
CONFIG_SYSTEM_BLACKLIST_HASH_LIST to the filename of a list of hashes
that are in the form:
"<hash>", "<hash>", ..., "<hash>"
where each <hash> is a hex string representation of the hash and must
include all necessary leading zeros to pad the hash to the right size.
The above are enabled with CONFIG_SYSTEM_BLACKLIST_KEYRING.
Once the kernel is booted, the blacklist keyring can be listed:
root@andromeda ~]# keyctl show %:.blacklist
Keyring
723359729 ---lswrv 0 0 keyring: .blacklist
676257228 ---lswrv 0 0 \_ blacklist: 123412341234c55c1dcc601ab8e172917706aa32fb5eaf826813547fdf02dd46
The blacklist cannot currently be modified by userspace, but it will be
possible to load it, for example, from the UEFI blacklist database.
A later commit will make it possible to load blacklisted asymmetric keys in
here too.
Signed-off-by: David Howells <dhowells@redhat.com>
105 lines
4 KiB
Makefile
105 lines
4 KiB
Makefile
#
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# Makefile for the linux kernel signature checking certificates.
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#
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obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
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obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o
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ifneq ($(CONFIG_SYSTEM_BLACKLIST_HASH_LIST),"")
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obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_hashes.o
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else
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obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
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endif
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ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
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$(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
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# GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
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$(obj)/system_certificates.o: $(obj)/x509_certificate_list
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# Cope with signing_key.x509 existing in $(srctree) not $(objtree)
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AFLAGS_system_certificates.o := -I$(srctree)
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quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
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cmd_extract_certs = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
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targets += x509_certificate_list
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$(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
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$(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
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endif
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clean-files := x509_certificate_list .x509.list
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ifeq ($(CONFIG_MODULE_SIG),y)
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###############################################################################
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#
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# If module signing is requested, say by allyesconfig, but a key has not been
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# supplied, then one will need to be generated to make sure the build does not
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# fail and that the kernel may be used afterwards.
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#
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###############################################################################
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ifndef CONFIG_MODULE_SIG_HASH
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$(error Could not determine digest type to use from kernel config)
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endif
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redirect_openssl = 2>&1
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quiet_redirect_openssl = 2>&1
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silent_redirect_openssl = 2>/dev/null
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# We do it this way rather than having a boolean option for enabling an
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# external private key, because 'make randconfig' might enable such a
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# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
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ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
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$(obj)/signing_key.pem: $(obj)/x509.genkey
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@$(kecho) "###"
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@$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
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@$(kecho) "###"
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@$(kecho) "### If this takes a long time, you might wish to run rngd in the"
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@$(kecho) "### background to keep the supply of entropy topped up. It"
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@$(kecho) "### needs to be run as root, and uses a hardware random"
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@$(kecho) "### number generator if one is available."
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@$(kecho) "###"
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$(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
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-batch -x509 -config $(obj)/x509.genkey \
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-outform PEM -out $(obj)/signing_key.pem \
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-keyout $(obj)/signing_key.pem \
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$($(quiet)redirect_openssl)
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@$(kecho) "###"
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@$(kecho) "### Key pair generated."
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@$(kecho) "###"
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$(obj)/x509.genkey:
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@$(kecho) Generating X.509 key generation config
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@echo >$@ "[ req ]"
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@echo >>$@ "default_bits = 4096"
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@echo >>$@ "distinguished_name = req_distinguished_name"
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@echo >>$@ "prompt = no"
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@echo >>$@ "string_mask = utf8only"
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@echo >>$@ "x509_extensions = myexts"
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@echo >>$@
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@echo >>$@ "[ req_distinguished_name ]"
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@echo >>$@ "#O = Unspecified company"
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@echo >>$@ "CN = Build time autogenerated kernel key"
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@echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
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@echo >>$@
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@echo >>$@ "[ myexts ]"
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@echo >>$@ "basicConstraints=critical,CA:FALSE"
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@echo >>$@ "keyUsage=digitalSignature"
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@echo >>$@ "subjectKeyIdentifier=hash"
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@echo >>$@ "authorityKeyIdentifier=keyid"
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endif
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$(eval $(call config_filename,MODULE_SIG_KEY))
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# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
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ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
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X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
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endif
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# GCC PR#66871 again.
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$(obj)/system_certificates.o: $(obj)/signing_key.x509
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targets += signing_key.x509
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$(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
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$(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))
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endif
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