set-verity-state: Use ro.boot.veritymode to determine current verity state
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
diff --git a/fs_mgr/fs_mgr_remount.cpp b/fs_mgr/fs_mgr_remount.cpp
index eac3ff2..1040a18 100644
--- a/fs_mgr/fs_mgr_remount.cpp
+++ b/fs_mgr/fs_mgr_remount.cpp
@@ -445,30 +445,33 @@
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};
}