ACPR/android_system_core
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

set-verity-state: Use ro.boot.veritymode to determine current verity state

Browse source 
On a device that don't use overlayfs remount (e.g. no EXT4 dup blocks;
this can be simulated by patching fs_mgr_wants_overlayfs()), if we run
disable-verity or enable-verity twice in a row then the second
invocation would not suggest a reboot:

  adb disable-verity
  > Successfully disabled verity
  > Reboot to take effect...
  adb disable-verity
  > Verity is already disabled
              ^^^ this is WRONG! verity is disabled only after a reboot

It behaves like this because it suggest a reboot only if the vbmeta
verity (HASHTREE) flag is changed.
Read the ro.boot.veritymode property instead to determine the current
dm-verity state and suggest a reboot by comparing current and future
verity state:
* If AVB verification is disabled, then ro.boot.veritymode is undefined
  (probably empty), don't suggest reboot in this case as it's pointless.
* Otherwise suggest a reboot if the new state (which would take effect
  after reboot) differs from the current verity state.
* Reference:
  https://android.googlesource.com/platform/external/avb/+/master/README.md#handling-dm_verity-errors

Bug: 241688845
Test: adb-remount-test
Test: Run "adb enable-verity" & "adb disable-verity" multiple times
Change-Id: If1df5bee6e5dcbda580b3dff6c32da93d08bbb46
This commit is contained in:
Yi-Yo Chiang 2022-11-03 21:20:08 +08:00
parent 2a501a11dc
commit ab4dd01395
1 changed files with 17 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

31
fs_mgr/fs_mgr_remount.cpp
View file

@ -445,30 +445,33 @@ struct SetVerityStateResult {
SetVerityStateResult SetVerityState(bool enable_verity) {
const auto ab_suffix = android::base::GetProperty("ro.boot.slot_suffix", "");
bool verity_enabled = false;
std::unique_ptr<AvbOps, decltype(&avb_ops_user_free)> ops(avb_ops_user_new(),
&avb_ops_user_free);
if (!ops) {
LOG(ERROR) << "Error getting AVB ops";
return {};
}
if (!avb_user_verity_get(ops.get(), ab_suffix.c_str(), &verity_enabled)) {
LOG(ERROR) << "Error getting verity state";
return {};
}
if ((verity_enabled && enable_verity) || (!verity_enabled && !enable_verity)) {
LOG(INFO) << "Verity is already " << (verity_enabled ? "enabled" : "disabled");
return {.success = true, .want_reboot = false};
}
if (!avb_user_verity_set(ops.get(), ab_suffix.c_str(), enable_verity)) {
LOG(ERROR) << "Error setting verity state";
return {};
}
bool verification_enabled = false;
if (!avb_user_verification_get(ops.get(), ab_suffix.c_str(), &verification_enabled)) {
LOG(ERROR) << "Error getting verification state";
return {};
}
if (!verification_enabled) {
LOG(WARNING) << "AVB verification is disabled, "
<< (enable_verity ? "enabling" : "disabling")
<< " verity state may have no effect";
return {.success = true, .want_reboot = false};
}
const auto verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
const bool was_enabled = (verity_mode != "disabled");
if ((was_enabled && enable_verity) || (!was_enabled && !enable_verity)) {
LOG(INFO) << "Verity is already " << (enable_verity ? "enabled" : "disabled");
return {.success = true, .want_reboot = false};
}
LOG(INFO) << "Successfully " << (enable_verity ? "enabled" : "disabled") << " verity";
return {.success = true, .want_reboot = true};
}