commit aff72001751f046d17209a1679d496923716b71d
author Miriam Polzer <mpolzer@google.com> Thu Aug 27 08:20:39 2020 +0200
committer Commit Bot <commit-bot@chromium.org> Mon Sep 28 20:51:50 2020 +0000
tree 56fba58cedd76c8d39d7a26cbed5ace6d5239302
parent d55ec44bfcb77ff204c3274b53394d451e0f7a03

update_engine: Enterprise channel downgrade

Powerwash and roll back when an enrolled user downgrades the channel:
- If the admin downgrades channel, check for ChannelDowngradebehavior
policy.
- If the user downgrades the channel, powerwash based on given boolean.

Add the "rollback" flag to the powerwash file to try to preserve some
data.

Note that this change is not affecting users yet: The
ChannelDowngradeBehavior policy is not available in DPanel and the UI
does not support chosing powerwash on channel downgrade for enrolled
users.

BUG=chromium:1122531
TEST=FEATURES=test emerge-amd64-generic update_engine
TEST=Set policy with YAPS and test on device

Change-Id: I2f02a6e752eed083b57484766f8e7ecc2eed7aca
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2397890
Tested-by: Miriam Polzer <mpolzer@google.com>
Commit-Queue: Miriam Polzer <mpolzer@google.com>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>

omaha_response_handler_action.cc

diff --git a/omaha_response_handler_action.cc b/omaha_response_handler_action.cc
index 040f8e7..92e0a72 100644
--- a/omaha_response_handler_action.cc
+++ b/omaha_response_handler_action.cc
@@ -188,10 +188,12 @@
   }
 
   // Powerwash if either the response requires it or the parameters indicated
-  // powerwash and we are downgrading the version.
+  // powerwash (usually because there was a channel downgrade) and we are
+  // downgrading the version. Enterprise rollback, indicated by
+  // |response.is_rollback| is dealt with separately above.
   if (response.powerwash_required) {
     install_plan_.powerwash_required = true;
-  } else if (params->ShouldPowerwash()) {
+  } else if (params->ShouldPowerwash() && !response.is_rollback) {
     base::Version new_version(response.version);
     base::Version current_version(params->app_version());
 
@@ -205,6 +207,10 @@
                    << " Current version number: " << params->app_version();
     } else if (new_version < current_version) {
       install_plan_.powerwash_required = true;
+      // Always try to preserve enrollment and wifi data for enrolled devices.
+      install_plan_.rollback_data_save_requested =
+          system_state_ && system_state_->device_policy() &&
+          system_state_->device_policy()->IsEnterpriseEnrolled();
     }
   }