update_engine: Add GetMinFirmwareKeyVersion to read tpm_fwver value
Add function to read the minimum allowed firmware key version, ie.
crossystem tpm_fwver.
This is the firmware key version equivalent of crrev.com/c/927827.
BUG=chromium:840432
TEST='cros_run_unit_tests --board=caroline --packages update_engine'
Change-Id: Iadd56b3283028722c94e4ebc7cf5b6470cf1fec9
Reviewed-on: https://chromium-review.googlesource.com/1049667
Commit-Ready: Marton Hunyady <hunyadym@chromium.org>
Tested-by: Marton Hunyady <hunyadym@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
diff --git a/common/hardware_interface.h b/common/hardware_interface.h
index 9f3f618..4946b91 100644
--- a/common/hardware_interface.h
+++ b/common/hardware_interface.h
@@ -73,6 +73,11 @@
// -1 on error, or if not running on Chrome OS.
virtual int GetMinKernelKeyVersion() const = 0;
+ // Returns the minimum firmware key version that verified boot on Chrome OS
+ // will allow to boot. This is the value of crossystem tpm_fwver. Returns
+ // -1 on error, or if not running on Chrome OS.
+ virtual int GetMinFirmwareKeyVersion() const = 0;
+
// Sets the maximum kernel key version that verified boot should roll
// forward to. This is the value of crossystem max_kernel_rollforward.
// Returns false if the value cannot be set, or if not running on Chrome OS.