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remount: Merge 'remount' and 'set-verity-state'

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Dedup fs_mgr_remount.cpp and set-verity-state.cpp by merging them
together and make '/system/bin/set-verity-state' a symlink to
'/system/bin/remount'.

Bug: 241688845
Test: adb-remount-test
Change-Id: I42a2344b9bdac112bf8767d428a99cb020267546
This commit is contained in:
Yi-Yo Chiang 2022-10-31 19:45:11 +08:00
parent a799a58842
commit e8d85b5814
3 changed files with 145 additions and 308 deletions
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37
fs_mgr/Android.bp
View file

@ -251,41 +251,8 @@ cc_binary {
},
symlinks: [
"clean_scratch_files",
],
}
cc_binary {
name: "set-verity-state",
srcs: ["set-verity-state.cpp"],
shared_libs: [
"libbase",
"libbinder",
"libcrypto",
"libcrypto_utils",
"libfs_mgr_binder",
"libutils",
],
static_libs: [
"libavb_user",
],
header_libs: [
"libcutils_headers",
],
cflags: ["-Werror"],
cppflags: [
"-DALLOW_DISABLE_VERITY=0",
],
product_variables: {
debuggable: {
cppflags: [
"-UALLOW_DISABLE_VERITY",
"-DALLOW_DISABLE_VERITY=1",
],
},
},
symlinks: [
"enable-verity",
"disable-verity",
"enable-verity",
"set-verity-state",
],
}

158
fs_mgr/fs_mgr_remount.cpp
View file

@ -22,6 +22,7 @@
#include <sys/vfs.h>
#include <unistd.h>
#include <iostream>
#include <string>
#include <thread>
#include <utility>
@ -33,6 +34,7 @@
#include <android-base/strings.h>
#include <android/os/IVold.h>
#include <binder/IServiceManager.h>
#include <binder/ProcessState.h>
#include <bootloader_message/bootloader_message.h>
#include <cutils/android_reboot.h>
#include <fs_mgr_overlayfs.h>
@ -50,17 +52,34 @@ using android::fs_mgr::FstabEntry;
namespace {
void usage() {
LOG(INFO) << getprogname()
<< " [-h] [-R] [-T fstab_file] [partition]...\n"
"\t-h --help\tthis help\n"
"\t-R --reboot\tdisable verity & reboot to facilitate remount\n"
"\t-T --fstab\tcustom fstab file location\n"
"\tpartition\tspecific partition(s) (empty does all)\n"
"\n"
"Remount specified partition(s) read-write, by name or mount point.\n"
"-R notwithstanding, verity must be disabled on partition(s).\n"
"-R within a DSU guest system reboots into the DSU instead of the host system,\n"
"this command would enable DSU (one-shot) if not already enabled.";
const std::string progname = getprogname();
if (progname == "disable-verity" || progname == "enable-verity" ||
progname == "set-verity-state") {
std::cout << "Usage: disable-verity\n"
<< " enable-verity\n"
<< " set-verity-state [0|1]\n"
<< R"(
Options:
-h --help this help
-R --reboot automatic reboot if needed for new settings to take effect
-v --verbose be noisy)"
<< std::endl;
} else {
std::cout << "Usage: " << progname << " [-h] [-R] [-T fstab_file] [partition]...\n"
<< R"(
Options:
-h --help this help
-R --reboot disable verity & reboot to facilitate remount
-v --verbose be noisy
-T --fstab custom fstab file location
partition specific partition(s) (empty does all)
Remount specified partition(s) read-write, by name or mount point.
-R notwithstanding, verity must be disabled on partition(s).
-R within a DSU guest system reboots into the DSU instead of the host system,
this command would enable DSU (one-shot) if not already enabled.)"
<< std::endl;
}
}
const std::string system_mount_point(const android::fs_mgr::FstabEntry& entry) {
@ -120,8 +139,6 @@ static android::sp<android::os::IVold> GetVold() {
}
}
} // namespace
enum RemountStatus {
REMOUNT_SUCCESS = 0,
UNKNOWN_PARTITION = 5,
@ -421,6 +438,68 @@ static RemountStatus RemountPartition(Fstab& fstab, Fstab& mounts, FstabEntry& e
return REMOUNT_FAILED;
}
struct SetVerityStateResult {
bool success = false;
bool want_reboot = false;
};
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 {};
}
LOG(INFO) << "Successfully " << (enable_verity ? "enabled" : "disabled") << " verity";
return {.success = true, .want_reboot = true};
}
bool SetupOrTeardownOverlayfs(bool enable) {
bool want_reboot = false;
if (enable) {
if (!fs_mgr_overlayfs_setup(nullptr, &want_reboot)) {
LOG(ERROR) << "Overlayfs setup failed.";
return want_reboot;
}
if (want_reboot) {
printf("enabling overlayfs\n");
}
} else {
auto rv = fs_mgr_overlayfs_teardown(nullptr, &want_reboot);
if (rv == OverlayfsTeardownResult::Error) {
LOG(ERROR) << "Overlayfs teardown failed.";
return want_reboot;
}
if (rv == OverlayfsTeardownResult::Busy) {
LOG(ERROR) << "Overlayfs is still active until reboot.";
return true;
}
if (want_reboot) {
printf("disabling overlayfs\n");
}
}
return want_reboot;
}
static int do_remount(Fstab& fstab, const std::vector<std::string>& partition_args,
RemountCheckResult* check_result) {
Fstab partitions;
@ -466,6 +545,8 @@ static int do_remount(Fstab& fstab, const std::vector<std::string>& partition_ar
return retval;
}
} // namespace
int main(int argc, char* argv[]) {
// Do not use MyLogger() when running as clean_scratch_files, as stdout/stderr of daemon process
// are discarded.
@ -518,8 +599,25 @@ int main(int argc, char* argv[]) {
android::base::SetLogger(MyLogger(verbose));
}
for (; argc > optind; ++optind) {
partition_args.emplace_back(argv[optind]);
bool remount = false;
bool enable_verity = false;
const std::string progname = getprogname();
if (progname == "enable-verity") {
enable_verity = true;
} else if (progname == "disable-verity") {
enable_verity = false;
} else if (progname == "set-verity-state") {
if (optind < argc && (argv[optind] == "1"s || argv[optind] == "0"s)) {
enable_verity = (argv[optind] == "1"s);
} else {
usage();
return 1;
}
} else {
remount = true;
for (; optind < argc; ++optind) {
partition_args.emplace_back(argv[optind]);
}
}
// Make sure we are root.
@ -541,6 +639,36 @@ int main(int argc, char* argv[]) {
return 1;
}
// Start a threadpool to service waitForService() callbacks as
// fs_mgr_overlayfs_* might call waitForService() to get the image service.
android::ProcessState::self()->startThreadPool();
if (!remount) {
// Figure out if we're using VB1.0 or VB2.0 (aka AVB) - by
// contract, androidboot.vbmeta.digest is set by the bootloader
// when using AVB).
if (android::base::GetProperty("ro.boot.vbmeta.digest", "").empty()) {
LOG(ERROR) << "Expected AVB device, VB1.0 is no longer supported";
return 1;
}
auto ret = SetVerityState(enable_verity);
// Disable any overlayfs unconditionally if we want verity enabled.
// Enable overlayfs only if verity is successfully disabled or is already disabled.
if (enable_verity || ret.success) {
ret.want_reboot |= SetupOrTeardownOverlayfs(!enable_verity);
}
if (ret.want_reboot) {
if (auto_reboot) {
reboot(progname);
}
std::cout << "Reboot the device for new settings to take effect" << std::endl;
}
return ret.success ? 0 : 1;
}
// Make sure checkpointing is disabled if necessary.
if (auto rv = VerifyCheckpointing(); rv != REMOUNT_SUCCESS) {
return rv;

258
fs_mgr/set-verity-state.cpp
View file

@ -1,258 +0,0 @@
/*
* Copyright (C) 2019 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 <getopt.h>
#include <stdio.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <binder/ProcessState.h>
#include <cutils/android_reboot.h>
#include <fs_mgr_overlayfs.h>
#include <libavb_user/libavb_user.h>
#include "fs_mgr_priv_overlayfs.h"
using namespace std::string_literals;
namespace {
void print_usage() {
printf("Usage:\n"
"\tdisable-verity\n"
"\tenable-verity\n"
"\tset-verity-state [0|1]\n"
"Options:\n"
"\t-h --help\tthis help\n"
"\t-R --reboot\tautomatic reboot if needed for new settings to take effect\n"
"\t-v --verbose\tbe noisy\n");
}
#ifdef ALLOW_DISABLE_VERITY
const bool kAllowDisableVerity = true;
#else
const bool kAllowDisableVerity = false;
#endif
static bool SetupOrTeardownOverlayfs(bool enable) {
bool want_reboot = false;
if (enable) {
if (!fs_mgr_overlayfs_setup(nullptr, &want_reboot)) {
LOG(ERROR) << "Overlayfs setup failed.";
return want_reboot;
}
if (want_reboot) {
printf("enabling overlayfs\n");
}
} else {
auto rv = fs_mgr_overlayfs_teardown(nullptr, &want_reboot);
if (rv == OverlayfsTeardownResult::Error) {
LOG(ERROR) << "Overlayfs teardown failed.";
return want_reboot;
}
if (rv == OverlayfsTeardownResult::Busy) {
LOG(ERROR) << "Overlayfs is still active until reboot.";
return true;
}
if (want_reboot) {
printf("disabling overlayfs\n");
}
}
return want_reboot;
}
/* Helper function to get A/B suffix, if any. If the device isn't
* using A/B the empty string is returned. Otherwise either "_a",
* "_b", ... is returned.
*/
std::string get_ab_suffix() {
return android::base::GetProperty("ro.boot.slot_suffix", "");
}
bool is_avb_device_locked() {
return android::base::GetProperty("ro.boot.vbmeta.device_state", "") == "locked";
}
bool is_debuggable() {
return android::base::GetBoolProperty("ro.debuggable", false);
}
bool is_using_avb() {
// Figure out if we're using VB1.0 or VB2.0 (aka AVB) - by
// contract, androidboot.vbmeta.digest is set by the bootloader
// when using AVB).
return !android::base::GetProperty("ro.boot.vbmeta.digest", "").empty();
}
[[noreturn]] void reboot(const std::string& name) {
LOG(INFO) << "Rebooting device for new settings to take effect";
::sync();
android::base::SetProperty(ANDROID_RB_PROPERTY, "reboot," + name);
::sleep(60);
LOG(ERROR) << "Failed to reboot";
::exit(1);
}
struct SetVerityStateResult {
bool success = false;
bool want_reboot = false;
};
/* Use AVB to turn verity on/off */
SetVerityStateResult SetVerityState(bool enable_verity) {
std::string ab_suffix = get_ab_suffix();
bool verity_enabled = false;
if (is_avb_device_locked()) {
LOG(ERROR) << "Device must be bootloader unlocked to change verity state";
return {};
}
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 {};
}
LOG(INFO) << "Successfully " << (enable_verity ? "enabled" : "disabled") << " verity";
return {.success = true, .want_reboot = true};
}
class MyLogger {
public:
explicit MyLogger(bool verbose) : verbose_(verbose) {}
void operator()(android::base::LogId id, android::base::LogSeverity severity, const char* tag,
const char* file, unsigned int line, const char* message) {
// Hide log starting with '[fs_mgr]' unless it's an error.
if (verbose_ || severity >= android::base::ERROR || message[0] != '[') {
fprintf(stderr, "%s\n", message);
}
logd_(id, severity, tag, file, line, message);
}
private:
android::base::LogdLogger logd_;
bool verbose_;
};
} // namespace
int main(int argc, char* argv[]) {
bool auto_reboot = false;
bool verbose = false;
struct option longopts[] = {
{"help", no_argument, nullptr, 'h'},
{"reboot", no_argument, nullptr, 'R'},
{"verbose", no_argument, nullptr, 'v'},
{0, 0, nullptr, 0},
};
for (int opt; (opt = ::getopt_long(argc, argv, "hRv", longopts, nullptr)) != -1;) {
switch (opt) {
case 'h':
print_usage();
return 0;
case 'R':
auto_reboot = true;
break;
case 'v':
verbose = true;
break;
default:
print_usage();
return 1;
}
}
android::base::InitLogging(argv, MyLogger(verbose));
bool enable_verity = false;
const std::string progname = getprogname();
if (progname == "enable-verity") {
enable_verity = true;
} else if (progname == "disable-verity") {
enable_verity = false;
} else if (optind < argc && (argv[optind] == "1"s || argv[optind] == "0"s)) {
// progname "set-verity-state"
enable_verity = (argv[optind] == "1"s);
} else {
print_usage();
return 1;
}
if (!kAllowDisableVerity || !is_debuggable()) {
errno = EPERM;
PLOG(ERROR) << "Cannot disable/enable verity on user build";
return 1;
}
if (getuid() != 0) {
errno = EACCES;
PLOG(ERROR) << "Must be running as root (adb root)";
return 1;
}
if (!is_using_avb()) {
LOG(ERROR) << "Expected AVB device, VB1.0 is no longer supported";
return 1;
}
int exit_code = 0;
bool want_reboot = false;
auto ret = SetVerityState(enable_verity);
if (ret.success) {
want_reboot |= ret.want_reboot;
} else {
exit_code = 1;
}
// Disable any overlayfs unconditionally if we want verity enabled.
// Enable overlayfs only if verity is successfully disabled or is already disabled.
if (enable_verity || ret.success) {
// Start a threadpool to service waitForService() callbacks as
// fs_mgr_overlayfs_* might call waitForService() to get the image service.
android::ProcessState::self()->startThreadPool();
want_reboot |= SetupOrTeardownOverlayfs(!enable_verity);
}
if (want_reboot) {
if (auto_reboot) {
reboot(progname);
}
printf("Reboot the device for new settings to take effect\n");
}
return exit_code;
}