security/intel/cbnt: Generate KM from Kconfig symbols
Add an option to generate the Key Manifest from Kconfig options.
Change-Id: I3a448f37c81148625c7879dcb64da4d517567067
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50410
Reviewed-by: Christian Walter <christian.walter@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/security/intel/cbnt/Kconfig b/src/security/intel/cbnt/Kconfig
index 8c4d999..0f4c216 100644
--- a/src/security/intel/cbnt/Kconfig
+++ b/src/security/intel/cbnt/Kconfig
@@ -21,13 +21,22 @@
default y
select INTEL_CBNT_NEED_KM_PUB_KEY
select INTEL_CBNT_NEED_KM_PRIV_KEY
+ select INTEL_CBNT_NEED_BPM_PUB_KEY if !INTEL_CBNT_BG_PROV_KM_USE_CFG_FILE
help
Select y to generate the Key Manifest (KM).
Select n to include a KM binary.
+config INTEL_CBNT_BG_PROV_KM_USE_CFG_FILE
+ bool "KM: use a CBnT json config file"
+ depends on INTEL_CBNT_GENERATE_KM
+ default y
+ help
+ Select y to generate KM from a json config file.
+ Select n to generate KM from Kconfig options
+
config INTEL_CBNT_BG_PROV_CFG_FILE
string "CBnT json config file"
- depends on INTEL_CBNT_GENERATE_KM
+ depends on INTEL_CBNT_BG_PROV_KM_USE_CFG_FILE
help
Location of the bg-prov json config file.
Either get a sample JSON config file:
@@ -71,6 +80,45 @@
help
Location of the boot policy manifest (BPM) private key file in .pem format.
+if !INTEL_CBNT_BG_PROV_KM_USE_CFG_FILE && INTEL_CBNT_GENERATE_KM
+
+menu "KM options"
+
+config INTEL_CBNT_KM_REVISION
+ int "KM revision"
+ default 1
+ help
+ Version of the Key Manifest defined by the Platform Manufacturer.
+ The actual value is transparent to Boot Guard and is not processed by Boot Guard.
+
+config INTEL_CBNT_KM_SVN
+ int "KM security Version Number"
+ range 0 15
+ default 0
+ help
+ This value is determined by the Platform Manufacturer.
+ Boot Guard uses this to compare it to the Key Manifest
+ Revocation Value (Revocation.KMSVN) in FPF.
+
+ If KMSVN < Revocation.KMSVN, the KM will be revoked. It will trigger ENF (the
+ enforcement policy).
+ IF KMSVN > Revocation.KMSVN, the Revocation.KMSVN will be set to the KMSVN.
+
+ Note: Once the value reaches 0Fh, revocation saturates and one can no longer
+ revoke newer KMs.
+
+config INTEL_CBNT_KM_ID
+ int "KM ID"
+ default 1
+ help
+ This identifies the Key Manifest to be used for a platform.
+ This must match the Key Manifest Identifier programmed in
+ the field programmable fuses.
+
+endmenu
+
+endif # !INTEL_CBNT_BG_PROV_KM_USE_CFG_FILE
+
config INTEL_CBNT_KEY_MANIFEST_BINARY
string "KM (Key Manifest) binary location"
depends on !INTEL_CBNT_GENERATE_KM
diff --git a/src/security/intel/cbnt/Makefile.inc b/src/security/intel/cbnt/Makefile.inc
index b508974..62b12f0 100644
--- a/src/security/intel/cbnt/Makefile.inc
+++ b/src/security/intel/cbnt/Makefile.inc
@@ -44,9 +44,22 @@
endif
ifeq ($(CONFIG_INTEL_CBNT_GENERATE_KM),y)
+ifeq ($(CONFIG_INTEL_CBNT_BG_PROV_KM_USE_CFG_FILE),y)
$(obj)/km_unsigned.bin: $(obj)/km_pub.pem $(BG_PROV) $(CBNT_CFG)
printf " BG_PROV creating unsigned KM using config file\n"
$(BG_PROV) km-gen $@ $< --config=$(CBNT_CFG)
+else
+PK_HASH_ALG_SHA256:=11 # Hardcode as no other options are available for CBnT
+$(obj)/km_unsigned.bin: $(obj)/km_pub.pem $(obj)/bpm_pub.pem $(BG_PROV)
+ printf " BG_PROV creating unsigned KM\n"
+ $(BG_PROV) km-gen $@ $< --revision=$(CONFIG_INTEL_CBNT_KM_REVISION) \
+ --svn=$(CONFIG_INTEL_CBNT_KM_SVN) \
+ --id=$(CONFIG_INTEL_CBNT_KM_ID) \
+ --pkhashalg=$(PK_HASH_ALG_SHA256) \
+ --bpmpubkey=$(obj)/bpm_pub.pem \
+ --bpmhashalgo=$(PK_HASH_ALG_SHA256) \
+ --out=$(obj)/km_cfg.json
+endif
$(obj)/km.bin: $(obj)/km_unsigned.bin $(BG_PROV) $(call strip_quotes, $(CONFIG_INTEL_CBNT_KM_PRIV_KEY_FILE))
printf " BG_PROV signing KM\n"