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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "first_stage_mount.h"
#include <stdlib.h>
#include <sys/mount.h>
#include <unistd.h>
#include <chrono>
#include <filesystem>
#include <map>
#include <memory>
#include <set>
#include <string>
#include <vector>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <fs_avb/fs_avb.h>
#include <fs_mgr.h>
#include <fs_mgr_dm_linear.h>
#include <fs_mgr_overlayfs.h>
#include <libfiemap/image_manager.h>
#include <libgsi/libgsi.h>
#include <liblp/liblp.h>
#include <libsnapshot/snapshot.h>
#include "block_dev_initializer.h"
#include "devices.h"
#include "result.h"
#include "snapuserd_transition.h"
#include "switch_root.h"
#include "uevent.h"
#include "uevent_listener.h"
#include "util.h"
using android::base::ReadFileToString;
using android::base::Result;
using android::base::Split;
using android::base::StringPrintf;
using android::base::Timer;
using android::fiemap::IImageManager;
using android::fs_mgr::AvbHandle;
using android::fs_mgr::AvbHandleStatus;
using android::fs_mgr::AvbHashtreeResult;
using android::fs_mgr::AvbUniquePtr;
using android::fs_mgr::Fstab;
using android::fs_mgr::FstabEntry;
using android::fs_mgr::ReadDefaultFstab;
using android::fs_mgr::ReadFstabFromDt;
using android::fs_mgr::SkipMountingPartitions;
using android::fs_mgr::TransformFstabForDsu;
using android::snapshot::SnapshotManager;
using namespace std::literals;
namespace android {
namespace init {
// Class Declarations
// ------------------
class FirstStageMountVBootV2 : public FirstStageMount {
public:
friend void SetInitAvbVersionInRecovery();
FirstStageMountVBootV2(Fstab fstab);
virtual ~FirstStageMountVBootV2() = default;
bool DoCreateDevices() override;
bool DoFirstStageMount() override;
private:
bool InitDevices();
bool InitRequiredDevices(std::set<std::string> devices);
bool CreateLogicalPartitions();
bool CreateSnapshotPartitions(SnapshotManager* sm);
bool MountPartition(const Fstab::iterator& begin, bool erase_same_mounts,
Fstab::iterator* end = nullptr);
bool MountPartitions();
bool TrySwitchSystemAsRoot();
bool IsDmLinearEnabled();
void GetSuperDeviceName(std::set<std::string>* devices);
bool InitDmLinearBackingDevices(const android::fs_mgr::LpMetadata& metadata);
void UseDsuIfPresent();
// Reads all fstab.avb_keys from the ramdisk for first-stage mount.
void PreloadAvbKeys();
// Copies /avb/*.avbpubkey used for DSU from the ramdisk to /metadata for key
// revocation check by DSU installation service.
void CopyDsuAvbKeys();
bool GetDmVerityDevices(std::set<std::string>* devices);
bool SetUpDmVerity(FstabEntry* fstab_entry);
bool InitAvbHandle();
bool need_dm_verity_;
bool dsu_not_on_userdata_ = false;
bool use_snapuserd_ = false;
Fstab fstab_;
// The super path is only set after InitDevices, and is invalid before.
std::string super_path_;
std::string super_partition_name_;
BlockDevInitializer block_dev_init_;
// Reads all AVB keys before chroot into /system, as they might be used
// later when mounting other partitions, e.g., /vendor and /product.
std::map<std::string, std::vector<std::string>> preload_avb_key_blobs_;
std::vector<std::string> vbmeta_partitions_;
AvbUniquePtr avb_handle_;
};
// Static Functions
// ----------------
static inline bool IsDtVbmetaCompatible(const Fstab& fstab) {
if (std::any_of(fstab.begin(), fstab.end(),
[](const auto& entry) { return entry.fs_mgr_flags.avb; })) {
return true;
}
return is_android_dt_value_expected("vbmeta/compatible", "android,vbmeta");
}
static Result<Fstab> ReadFirstStageFstabAndroid() {
Fstab fstab;
if (!ReadFstabFromDt(&fstab)) {
if (ReadDefaultFstab(&fstab)) {
fstab.erase(std::remove_if(fstab.begin(), fstab.end(),
[](const auto& entry) {
return !entry.fs_mgr_flags.first_stage_mount;
}),
fstab.end());
} else {
return Error() << "failed to read default fstab for first stage mount";
}
}
return fstab;
}
// Note: this is a temporary solution to avoid blocking devs that depend on /vendor partition in
// Microdroid. For the proper solution the /vendor fstab should probably be defined in the DT.
// TODO(b/285855430): refactor this
// TODO(b/285855436): verify key microdroid-vendor was signed with.
// TODO(b/285855436): should be mounted on top of dm-verity device.
static Result<Fstab> ReadFirstStageFstabMicrodroid(const std::string& cmdline) {
Fstab fstab;
if (!ReadDefaultFstab(&fstab)) {
return Error() << "failed to read fstab";
}
if (cmdline.find("androidboot.microdroid.mount_vendor=1") == std::string::npos) {
// We weren't asked to mount /vendor partition, filter it out from the fstab.
auto predicate = [](const auto& entry) { return entry.mount_point == "/vendor"; };
fstab.erase(std::remove_if(fstab.begin(), fstab.end(), predicate), fstab.end());
}
return fstab;
}
static bool GetRootEntry(FstabEntry* root_entry) {
Fstab proc_mounts;
if (!ReadFstabFromFile("/proc/mounts", &proc_mounts)) {
LOG(ERROR) << "Could not read /proc/mounts and /system not in fstab, /system will not be "
"available for overlayfs";
return false;
}
auto entry = std::find_if(proc_mounts.begin(), proc_mounts.end(), [](const auto& entry) {
return entry.mount_point == "/" && entry.fs_type != "rootfs";
});
if (entry == proc_mounts.end()) {
LOG(ERROR) << "Could not get mount point for '/' in /proc/mounts, /system will not be "
"available for overlayfs";
return false;
}
*root_entry = std::move(*entry);
// We don't know if we're avb or not, so we query device mapper as if we are avb. If we get a
// success, then mark as avb, otherwise default to verify.
auto& dm = android::dm::DeviceMapper::Instance();
if (dm.GetState("vroot") != android::dm::DmDeviceState::INVALID) {
root_entry->fs_mgr_flags.avb = true;
}
return true;
}
static bool IsStandaloneImageRollback(const AvbHandle& builtin_vbmeta,
const AvbHandle& standalone_vbmeta,
const FstabEntry& fstab_entry) {
std::string old_spl = builtin_vbmeta.GetSecurityPatchLevel(fstab_entry);
std::string new_spl = standalone_vbmeta.GetSecurityPatchLevel(fstab_entry);
bool rollbacked = false;
if (old_spl.empty() || new_spl.empty() || new_spl < old_spl) {
rollbacked = true;
}
if (rollbacked) {
LOG(ERROR) << "Image rollback detected for " << fstab_entry.mount_point
<< ", SPL switches from '" << old_spl << "' to '" << new_spl << "'";
if (AvbHandle::IsDeviceUnlocked()) {
LOG(INFO) << "Allowing rollbacked standalone image when the device is unlocked";
return false;
}
}
return rollbacked;
}
Result<std::unique_ptr<FirstStageMount>> FirstStageMount::Create(const std::string& cmdline) {
Result<Fstab> fstab;
if (IsMicrodroid()) {
fstab = ReadFirstStageFstabMicrodroid(cmdline);
} else {
fstab = ReadFirstStageFstabAndroid();
}
if (!fstab.ok()) {
return fstab.error();
}
return std::make_unique<FirstStageMountVBootV2>(std::move(*fstab));
}
bool FirstStageMountVBootV2::DoCreateDevices() {
if (!InitDevices()) return false;
// Mount /metadata before creating logical partitions, since we need to
// know whether a snapshot merge is in progress.
auto metadata_partition = std::find_if(fstab_.begin(), fstab_.end(), [](const auto& entry) {
return entry.mount_point == "/metadata";
});
if (metadata_partition != fstab_.end()) {
if (MountPartition(metadata_partition, true /* erase_same_mounts */)) {
// Copies DSU AVB keys from the ramdisk to /metadata.
// Must be done before the following TrySwitchSystemAsRoot().
// Otherwise, ramdisk will be inaccessible after switching root.
CopyDsuAvbKeys();
}
}
if (!CreateLogicalPartitions()) return false;
return true;
}
bool FirstStageMountVBootV2::DoFirstStageMount() {
if (!IsDmLinearEnabled() && fstab_.empty()) {
// Nothing to mount.
LOG(INFO) << "First stage mount skipped (missing/incompatible/empty fstab in device tree)";
return true;
}
if (!MountPartitions()) return false;
return true;
}
bool FirstStageMountVBootV2::InitDevices() {
std::set<std::string> devices;
GetSuperDeviceName(&devices);
if (!GetDmVerityDevices(&devices)) {
return false;
}
if (!InitRequiredDevices(std::move(devices))) {
return false;
}
if (IsDmLinearEnabled()) {
auto super_symlink = "/dev/block/by-name/"s + super_partition_name_;
if (!android::base::Realpath(super_symlink, &super_path_)) {
PLOG(ERROR) << "realpath failed: " << super_symlink;
return false;
}
}
return true;
}
bool FirstStageMountVBootV2::IsDmLinearEnabled() {
for (const auto& entry : fstab_) {
if (entry.fs_mgr_flags.logical) return true;
}
return false;
}
void FirstStageMountVBootV2::GetSuperDeviceName(std::set<std::string>* devices) {
// Add any additional devices required for dm-linear mappings.
if (!IsDmLinearEnabled()) {
return;
}
devices->emplace(super_partition_name_);
}
// Creates devices with uevent->partition_name matching ones in the given set.
// Found partitions will then be removed from it for the subsequent member
// function to check which devices are NOT created.
bool FirstStageMountVBootV2::InitRequiredDevices(std::set<std::string> devices) {
if (!block_dev_init_.InitDeviceMapper()) {
return false;
}
if (devices.empty()) {
return true;
}
return block_dev_init_.InitDevices(std::move(devices));
}
bool FirstStageMountVBootV2::InitDmLinearBackingDevices(
const android::fs_mgr::LpMetadata& metadata) {
std::set<std::string> devices;
auto partition_names = android::fs_mgr::GetBlockDevicePartitionNames(metadata);
for (const auto& partition_name : partition_names) {
// The super partition was found in the earlier pass.
if (partition_name == super_partition_name_) {
continue;
}
devices.emplace(partition_name);
}
if (devices.empty()) {
return true;
}
return InitRequiredDevices(std::move(devices));
}
bool FirstStageMountVBootV2::CreateLogicalPartitions() {
if (!IsDmLinearEnabled()) {
return true;
}
if (super_path_.empty()) {
LOG(ERROR) << "Could not locate logical partition tables in partition "
<< super_partition_name_;
return false;
}
if (SnapshotManager::IsSnapshotManagerNeeded()) {
auto sm = SnapshotManager::NewForFirstStageMount();
if (!sm) {
return false;
}
if (sm->NeedSnapshotsInFirstStageMount()) {
return CreateSnapshotPartitions(sm.get());
}
}
auto metadata = android::fs_mgr::ReadCurrentMetadata(super_path_);
if (!metadata) {
LOG(ERROR) << "Could not read logical partition metadata from " << super_path_;
return false;
}
if (!InitDmLinearBackingDevices(*metadata.get())) {
return false;
}
return android::fs_mgr::CreateLogicalPartitions(*metadata.get(), super_path_);
}
bool FirstStageMountVBootV2::CreateSnapshotPartitions(SnapshotManager* sm) {
// When COW images are present for snapshots, they are stored on
// the data partition.
if (!InitRequiredDevices({"userdata"})) {
return false;
}
use_snapuserd_ = sm->IsSnapuserdRequired();
if (use_snapuserd_) {
if (sm->UpdateUsesUserSnapshots()) {
LaunchFirstStageSnapuserd(SnapshotDriver::DM_USER);
} else {
LaunchFirstStageSnapuserd(SnapshotDriver::DM_SNAPSHOT);
}
}
sm->SetUeventRegenCallback([this](const std::string& device) -> bool {
if (android::base::StartsWith(device, "/dev/block/dm-")) {
return block_dev_init_.InitDmDevice(device);
}
if (android::base::StartsWith(device, "/dev/dm-user/")) {
return block_dev_init_.InitDmUser(android::base::Basename(device));
}
return block_dev_init_.InitDevices({device});
});
if (!sm->CreateLogicalAndSnapshotPartitions(super_path_)) {
return false;
}
if (use_snapuserd_) {
CleanupSnapuserdSocket();
}
return true;
}
bool FirstStageMountVBootV2::MountPartition(const Fstab::iterator& begin, bool erase_same_mounts,
Fstab::iterator* end) {
// Sets end to begin + 1, so we can just return on failure below.
if (end) {
*end = begin + 1;
}
if (!fs_mgr_create_canonical_mount_point(begin->mount_point)) {
return false;
}
if (begin->fs_mgr_flags.logical) {
if (!fs_mgr_update_logical_partition(&(*begin))) {
return false;
}
if (!block_dev_init_.InitDmDevice(begin->blk_device)) {
return false;
}
}
if (!SetUpDmVerity(&(*begin))) {
PLOG(ERROR) << "Failed to setup verity for '" << begin->mount_point << "'";
return false;
}
bool mounted = (fs_mgr_do_mount_one(*begin) == 0);
// Try other mounts with the same mount point.
Fstab::iterator current = begin + 1;
for (; current != fstab_.end() && current->mount_point == begin->mount_point; current++) {
if (!mounted) {
// blk_device is already updated to /dev/dm-<N> by SetUpDmVerity() above.
// Copy it from the begin iterator.
current->blk_device = begin->blk_device;
mounted = (fs_mgr_do_mount_one(*current) == 0);
}
}
if (erase_same_mounts) {
current = fstab_.erase(begin, current);
}
if (end) {
*end = current;
}
return mounted;
}
void FirstStageMountVBootV2::PreloadAvbKeys() {
for (const auto& entry : fstab_) {
// No need to cache the key content if it's empty, or is already cached.
if (entry.avb_keys.empty() || preload_avb_key_blobs_.count(entry.avb_keys)) {
continue;
}
// Determines all key paths first.
std::vector<std::string> key_paths;
if (is_dir(entry.avb_keys.c_str())) { // fstab_keys might be a dir, e.g., /avb.
const char* avb_key_dir = entry.avb_keys.c_str();
std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(avb_key_dir), closedir);
if (!dir) {
LOG(ERROR) << "Failed to opendir: " << dir;
continue;
}
// Gets all key pathes under the dir.
struct dirent* de;
while ((de = readdir(dir.get()))) {
if (de->d_type != DT_REG) continue;
std::string full_path = StringPrintf("%s/%s", avb_key_dir, de->d_name);
key_paths.emplace_back(std::move(full_path));
}
std::sort(key_paths.begin(), key_paths.end());
} else {
// avb_keys are key paths separated by ":", if it's not a dir.
key_paths = Split(entry.avb_keys, ":");
}
// Reads the key content then cache it.
std::vector<std::string> key_blobs;
for (const auto& path : key_paths) {
std::string key_value;
if (!ReadFileToString(path, &key_value)) {
continue;
}
key_blobs.emplace_back(std::move(key_value));
}
// Maps entry.avb_keys to actual key blobs.
preload_avb_key_blobs_[entry.avb_keys] = std::move(key_blobs);
}
}
// If system is in the fstab then we're not a system-as-root device, and in
// this case, we mount system first then pivot to it. From that point on,
// we are effectively identical to a system-as-root device.
bool FirstStageMountVBootV2::TrySwitchSystemAsRoot() {
UseDsuIfPresent();
// Preloading all AVB keys from the ramdisk before switching root to /system.
PreloadAvbKeys();
auto system_partition = std::find_if(fstab_.begin(), fstab_.end(), [](const auto& entry) {
return entry.mount_point == "/system";
});
if (system_partition == fstab_.end()) return true;
if (use_snapuserd_) {
SaveRamdiskPathToSnapuserd();
}
if (!MountPartition(system_partition, false /* erase_same_mounts */)) {
PLOG(ERROR) << "Failed to mount /system";
return false;
}
if (dsu_not_on_userdata_ && fs_mgr_verity_is_check_at_most_once(*system_partition)) {
LOG(ERROR) << "check_at_most_once forbidden on external media";
return false;
}
SwitchRoot("/system");
return true;
}
bool FirstStageMountVBootV2::MountPartitions() {
if (!TrySwitchSystemAsRoot()) return false;
if (!SkipMountingPartitions(&fstab_, true /* verbose */)) return false;
for (auto current = fstab_.begin(); current != fstab_.end();) {
// We've already mounted /system above.
if (current->mount_point == "/system") {
++current;
continue;
}
// Handle overlayfs entries later.
if (current->fs_type == "overlay") {
++current;
continue;
}
// Skip raw partition entries such as boot, dtbo, etc.
// Having emmc fstab entries allows us to probe current->vbmeta_partition
// in InitDevices() when they are AVB chained partitions.
if (current->fs_type == "emmc") {
++current;
continue;
}
Fstab::iterator end;
if (!MountPartition(current, false /* erase_same_mounts */, &end)) {
if (current->fs_mgr_flags.no_fail) {
LOG(INFO) << "Failed to mount " << current->mount_point
<< ", ignoring mount for no_fail partition";
} else if (current->fs_mgr_flags.formattable) {
LOG(INFO) << "Failed to mount " << current->mount_point
<< ", ignoring mount for formattable partition";
} else {
PLOG(ERROR) << "Failed to mount " << current->mount_point;
return false;
}
}
current = end;
}
for (const auto& entry : fstab_) {
if (entry.fs_type == "overlay") {
fs_mgr_mount_overlayfs_fstab_entry(entry);
}
}
// If we don't see /system or / in the fstab, then we need to create an root entry for
// overlayfs.
if (!GetEntryForMountPoint(&fstab_, "/system") && !GetEntryForMountPoint(&fstab_, "/")) {
FstabEntry root_entry;
if (GetRootEntry(&root_entry)) {
fstab_.emplace_back(std::move(root_entry));
}
}
// heads up for instantiating required device(s) for overlayfs logic
auto init_devices = [this](std::set<std::string> devices) -> bool {
for (auto iter = devices.begin(); iter != devices.end();) {
if (android::base::StartsWith(*iter, "/dev/block/dm-")) {
if (!block_dev_init_.InitDmDevice(*iter)) {
return false;
}
iter = devices.erase(iter);
} else {
iter++;
}
}
return InitRequiredDevices(std::move(devices));
};
MapScratchPartitionIfNeeded(&fstab_, init_devices);
fs_mgr_overlayfs_mount_all(&fstab_);
return true;
}
// Preserves /avb/*.avbpubkey to /metadata/gsi/dsu/avb/, so they can be used for
// key revocation check by DSU installation service. Note that failing to
// copy files to /metadata is NOT fatal, because it is auxiliary to perform
// public key matching before booting into DSU images on next boot. The actual
// public key matching will still be done on next boot to DSU.
void FirstStageMountVBootV2::CopyDsuAvbKeys() {
std::error_code ec;
// Removing existing keys in gsi::kDsuAvbKeyDir as they might be stale.
std::filesystem::remove_all(gsi::kDsuAvbKeyDir, ec);
if (ec) {
LOG(ERROR) << "Failed to remove directory " << gsi::kDsuAvbKeyDir << ": " << ec.message();
}
// Copy keys from the ramdisk /avb/* to gsi::kDsuAvbKeyDir.
static constexpr char kRamdiskAvbKeyDir[] = "/avb";
std::filesystem::copy(kRamdiskAvbKeyDir, gsi::kDsuAvbKeyDir, ec);
if (ec) {
LOG(ERROR) << "Failed to copy " << kRamdiskAvbKeyDir << " into " << gsi::kDsuAvbKeyDir
<< ": " << ec.message();
}
}
void FirstStageMountVBootV2::UseDsuIfPresent() {
std::string error;
if (!android::gsi::CanBootIntoGsi(&error)) {
LOG(INFO) << "DSU " << error << ", proceeding with normal boot";
return;
}
auto init_devices = [this](std::set<std::string> devices) -> bool {
if (devices.count("userdata") == 0 || devices.size() > 1) {
dsu_not_on_userdata_ = true;
}
return InitRequiredDevices(std::move(devices));
};
std::string active_dsu;
if (!gsi::GetActiveDsu(&active_dsu)) {
LOG(ERROR) << "Failed to GetActiveDsu";
return;
}
LOG(INFO) << "DSU slot: " << active_dsu;
auto images = IImageManager::Open("dsu/" + active_dsu, 0ms);
if (!images || !images->MapAllImages(init_devices)) {
LOG(ERROR) << "DSU partition layout could not be instantiated";
return;
}
if (!android::gsi::MarkSystemAsGsi()) {
PLOG(ERROR) << "DSU indicator file could not be written";
return;
}
// Publish the logical partition names for TransformFstabForDsu() and ReadFstabFromFile().
const auto dsu_partitions = images->GetAllBackingImages();
WriteFile(gsi::kGsiLpNamesFile, android::base::Join(dsu_partitions, ","));
TransformFstabForDsu(&fstab_, active_dsu, dsu_partitions);
}
FirstStageMountVBootV2::FirstStageMountVBootV2(Fstab fstab)
: need_dm_verity_(false), fstab_(std::move(fstab)), avb_handle_(nullptr) {
super_partition_name_ = fs_mgr_get_super_partition_name();
std::string device_tree_vbmeta_parts;
read_android_dt_file("vbmeta/parts", &device_tree_vbmeta_parts);
for (auto&& partition : Split(device_tree_vbmeta_parts, ",")) {
if (!partition.empty()) {
vbmeta_partitions_.emplace_back(std::move(partition));
}
}
for (const auto& entry : fstab_) {
if (!entry.vbmeta_partition.empty()) {
vbmeta_partitions_.emplace_back(entry.vbmeta_partition);
}
}
if (vbmeta_partitions_.empty()) {
LOG(ERROR) << "Failed to read vbmeta partitions.";
}
}
bool FirstStageMountVBootV2::GetDmVerityDevices(std::set<std::string>* devices) {
need_dm_verity_ = false;
std::set<std::string> logical_partitions;
// fstab_rec->blk_device has A/B suffix.
for (const auto& fstab_entry : fstab_) {
if (fstab_entry.fs_mgr_flags.avb) {
need_dm_verity_ = true;
}
// Skip pseudo filesystems.
if (fstab_entry.fs_type == "overlay") {
continue;
}
if (fstab_entry.fs_mgr_flags.logical) {
// Don't try to find logical partitions via uevent regeneration.
logical_partitions.emplace(basename(fstab_entry.blk_device.c_str()));
} else {
devices->emplace(basename(fstab_entry.blk_device.c_str()));
}
}
// Any partitions needed for verifying the partitions used in first stage mount, e.g. vbmeta
// must be provided as vbmeta_partitions.
if (need_dm_verity_) {
if (vbmeta_partitions_.empty()) {
LOG(ERROR) << "Missing vbmeta partitions";
return false;
}
std::string ab_suffix = fs_mgr_get_slot_suffix();
for (const auto& partition : vbmeta_partitions_) {
std::string partition_name = partition + ab_suffix;
if (logical_partitions.count(partition_name)) {
continue;
}
// devices is of type std::set so it's not an issue to emplace a
// partition twice. e.g., /vendor might be in both places:
// - device_tree_vbmeta_parts_ = "vbmeta,boot,system,vendor"
// - mount_fstab_recs_: /vendor_a
devices->emplace(partition_name);
}
}
return true;
}
bool FirstStageMountVBootV2::SetUpDmVerity(FstabEntry* fstab_entry) {
AvbHashtreeResult hashtree_result;
// It's possible for a fstab_entry to have both avb_keys and avb flag.
// In this case, try avb_keys first, then fallback to avb flag.
if (!fstab_entry->avb_keys.empty()) {
if (!InitAvbHandle()) return false;
// Checks if hashtree should be disabled from the top-level /vbmeta.
if (avb_handle_->status() == AvbHandleStatus::kHashtreeDisabled ||
avb_handle_->status() == AvbHandleStatus::kVerificationDisabled) {
LOG(ERROR) << "Top-level vbmeta is disabled, skip Hashtree setup for "
<< fstab_entry->mount_point;
return true; // Returns true to mount the partition directly.
} else {
auto avb_standalone_handle = AvbHandle::LoadAndVerifyVbmeta(
*fstab_entry, preload_avb_key_blobs_[fstab_entry->avb_keys]);
if (!avb_standalone_handle) {
LOG(ERROR) << "Failed to load offline vbmeta for " << fstab_entry->mount_point;
// Fallbacks to built-in hashtree if fs_mgr_flags.avb is set.
if (!fstab_entry->fs_mgr_flags.avb) return false;
LOG(INFO) << "Fallback to built-in hashtree for " << fstab_entry->mount_point;
hashtree_result =
avb_handle_->SetUpAvbHashtree(fstab_entry, false /* wait_for_verity_dev */);
} else {
// Sets up hashtree via the standalone handle.
if (IsStandaloneImageRollback(*avb_handle_, *avb_standalone_handle, *fstab_entry)) {
return false;
}
hashtree_result = avb_standalone_handle->SetUpAvbHashtree(
fstab_entry, false /* wait_for_verity_dev */);
}
}
} else if (fstab_entry->fs_mgr_flags.avb) {
if (!InitAvbHandle()) return false;
hashtree_result =
avb_handle_->SetUpAvbHashtree(fstab_entry, false /* wait_for_verity_dev */);
} else {
return true; // No need AVB, returns true to mount the partition directly.
}
switch (hashtree_result) {
case AvbHashtreeResult::kDisabled:
return true; // Returns true to mount the partition.
case AvbHashtreeResult::kSuccess:
// The exact block device name (fstab_rec->blk_device) is changed to
// "/dev/block/dm-XX". Needs to create it because ueventd isn't started in init
// first stage.
return block_dev_init_.InitDmDevice(fstab_entry->blk_device);
default:
return false;
}
}
bool FirstStageMountVBootV2::InitAvbHandle() {
if (avb_handle_) return true; // Returns true if the handle is already initialized.
avb_handle_ = AvbHandle::Open();
if (!avb_handle_) {
PLOG(ERROR) << "Failed to open AvbHandle";
return false;
}
// Sets INIT_AVB_VERSION here for init to set ro.boot.avb_version in the second stage.
setenv("INIT_AVB_VERSION", avb_handle_->avb_version().c_str(), 1);
return true;
}
void SetInitAvbVersionInRecovery() {
if (!IsRecoveryMode()) {
LOG(INFO) << "Skipped setting INIT_AVB_VERSION (not in recovery mode)";
return;
}
auto fstab = ReadFirstStageFstabAndroid();
if (!fstab.ok()) {
LOG(ERROR) << fstab.error();
return;
}
if (!IsDtVbmetaCompatible(*fstab)) {
LOG(INFO) << "Skipped setting INIT_AVB_VERSION (not vbmeta compatible)";
return;
}
// Initializes required devices for the subsequent AvbHandle::Open()
// to verify AVB metadata on all partitions in the verified chain.
// We only set INIT_AVB_VERSION when the AVB verification succeeds, i.e., the
// Open() function returns a valid handle.
// We don't need to mount partitions here in recovery mode.
FirstStageMountVBootV2 avb_first_mount(std::move(*fstab));
if (!avb_first_mount.InitDevices()) {
LOG(ERROR) << "Failed to init devices for INIT_AVB_VERSION";
return;
}
AvbUniquePtr avb_handle = AvbHandle::Open();
if (!avb_handle) {
PLOG(ERROR) << "Failed to open AvbHandle for INIT_AVB_VERSION";
return;
}
setenv("INIT_AVB_VERSION", avb_handle->avb_version().c_str(), 1);
}
} // namespace init
} // namespace android