fs_mgr_overlayfs: Cleanup -user build stubs
* Categorize functions in fs_mgr_overlayfs.h into three classes:
- Type 1: common and non-critical utilities.
- Type 2: internal routines for facilitating remount.
- Type 3: external entry points for users of fs_mgr_overlayfs, like
fs_mgr_overlayfs_mount_all().
* Move type 1 to common utils header fs_mgr_priv.h & fs_mgr.cpp.
* Move type 2 to new private header fs_mgr_priv_overlayfs.h.
* Keep type 3 in fs_mgr_overlayfs.h.
* Move set-verity-state.cpp under fs_mgr so it can include
fs_mgr_priv_overlayfs.h. File is reformatted as a result. We should
eventually merge and dedup set-verity-state and fs_mgr_remount.
* Add myself to OWNERS for remount-related maintenance work.
Bug: 241179247
Bug: 241688845
Test: Full build -user and -userdebug build.
Test: Presubmit
Test: Treehugger run v2/android-gki/adb_remount
Change-Id: Id5fd0e2b12c693939d712a586dd553cc4d8bfeb1
diff --git a/fs_mgr/set-verity-state.cpp b/fs_mgr/set-verity-state.cpp
new file mode 100644
index 0000000..84ee01f
--- /dev/null
+++ b/fs_mgr/set-verity-state.cpp
@@ -0,0 +1,258 @@
+/*
+ * 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;
+}