update_engine: Process Omaha response for rollback images
Omaha returns whether the image returned is a rollback in the
_rollback="true" argument. If this is set, the client has to check
whether it's OK to apply the rollback image (policy is specifically
requesting a rollback and verified boot will accept the image based
on its kernel and firmware key versions).
In addition to this, the device has to do a safe powerwash if the
image is a rollback. (We're not supporting rollbacks with partial
or no powerwash yet.)
We're also setting the rollback_happened preference to avoid force
updates happening before the policy is available again.
Chromium CL adding the error code: http://crrev.com/c/1047866
BUG=chromium:840432
TEST='cros_run_unit_tests --board=caroline --packages update_engine'
Change-Id: I1436ca96211b2a8523e78bf83602ef8b6b525570
Reviewed-on: https://chromium-review.googlesource.com/1047610
Commit-Ready: Marton Hunyady <hunyadym@chromium.org>
Tested-by: Marton Hunyady <hunyadym@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/omaha_response_handler_action.cc b/omaha_response_handler_action.cc
index f1a3310..3007f29 100644
--- a/omaha_response_handler_action.cc
+++ b/omaha_response_handler_action.cc
@@ -140,6 +140,26 @@
system_state_->prefs()->SetString(current_channel_key,
params->download_channel());
+ // Checking whether device is able to boot up the returned rollback image.
+ if (response.is_rollback) {
+ if (!params->rollback_allowed()) {
+ LOG(ERROR) << "Received rollback image but rollback is not allowed.";
+ completer.set_code(ErrorCode::kOmahaResponseInvalid);
+ return;
+ }
+ auto min_kernel_key_version = static_cast<uint32_t>(
+ system_state_->hardware()->GetMinKernelKeyVersion());
+ auto min_firmware_key_version = static_cast<uint32_t>(
+ system_state_->hardware()->GetMinFirmwareKeyVersion());
+ if (response.kernel_version < min_kernel_key_version ||
+ response.firmware_version < min_firmware_key_version) {
+ LOG(ERROR) << "Device won't be able to boot up the rollback image.";
+ completer.set_code(ErrorCode::kRollbackNotPossible);
+ return;
+ }
+ install_plan_.is_rollback = true;
+ }
+
if (params->ShouldPowerwash())
install_plan_.powerwash_required = true;