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remount: Check device mapper to see if verity is already disabled

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No matter verity is enabled or disabled, androidboot.veritymode is
always "enforcing" on emulator kernel cmdline.

This is a violation of the AVB contract:
https://cs.android.com/android/platform/superproject/+/master:external/avb/README.md#handling-dm-verity-errors

Before emulator can fix this, workaround this by checking the device
mapper table to see if verity is disabled or not.
If no "<partition>-verity" device is present, than assume verity is
already disabled.

Also log mountpoints that are successfully remounted.

Bug: 241688845
Bug: 259207493
Test: adb-remount-test
Test: Run adb remount on emulator
Change-Id: Id5767b05cbfb48adf2a8c372dfdad4d15b98e091
This commit is contained in:
Yi-Yo Chiang 2022-11-17 19:09:16 +08:00
parent 4cdb6cf415
commit f48d5778a1
1 changed files with 20 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

33
fs_mgr/fs_mgr_remount.cpp
View file

@ -386,16 +386,15 @@ bool RemountPartition(Fstab& fstab, Fstab& mounts, FstabEntry& entry) {
}
// Now remount!
if (::mount(blk_device.c_str(), mount_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
nullptr) == 0) {
return true;
}
if ((errno == EINVAL) && (mount_point != entry.mount_point)) {
mount_point = entry.mount_point;
if (::mount(blk_device.c_str(), mount_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
for (const auto& mnt_point : {mount_point, entry.mount_point}) {
if (::mount(blk_device.c_str(), mnt_point.c_str(), entry.fs_type.c_str(), MS_REMOUNT,
nullptr) == 0) {
LOG(INFO) << "Remounted " << mnt_point << " as RW";
return true;
}
if (errno != EINVAL || mount_point == entry.mount_point) {
break;
}
}
PLOG(ERROR) << "failed to remount partition dev:" << blk_device << " mnt:" << mount_point;
@ -484,8 +483,16 @@ bool do_remount(Fstab& fstab, const std::vector<std::string>& partition_args,
return false;
}
if (verity_result.want_reboot) {
check_result->reboot_later = true;
check_result->disabled_verity = true;
// TODO(b/259207493): emulator has incorrect androidboot.veritymode value, causing
// .want_reboot to always be true. In order to workaround this, double check device mapper
// to see if verity is already disabled.
for (const auto& partition : partitions) {
if (fs_mgr_is_verity_enabled(partition)) {
check_result->reboot_later = true;
check_result->disabled_verity = true;
break;
}
}
}
// Optionally setup overlayfs backing.
@ -660,10 +667,10 @@ int main(int argc, char* argv[]) {
} else if (check_result.setup_overlayfs) {
LOG(INFO) << "Overlayfs enabled.";
}
if (remount_success) {
LOG(INFO) << "remount succeeded";
} else {
LOG(ERROR) << "remount failed";
if (remount_success && check_result.remounted_anything) {
LOG(INFO) << "Remount succeeded";
} else if (!remount_success) {
LOG(ERROR) << "Remount failed";
}
if (check_result.reboot_later) {
if (auto_reboot) {