Merge "set-verity-state: Refactor & remove even more dead code" (2db51770) · Commits · e / os / android_system_core

set-verity-state/Android.bp

+0 −3

Original line number	Diff line number	Diff line
		@@ -11,10 +11,7 @@ cc_binary {
		"libbase",
		"libcrypto",
		"libcrypto_utils",
		"libcutils",
		"libfs_mgr_binder",
		"liblog",
		"libutils",
		],
		static_libs: [
		"libavb_user",

set-verity-state/set-verity-state.cpp

+59 −53

Original line number	Diff line number	Diff line
		@@ -14,85 +14,105 @@
		* limitations under the License.
		*/

		#include <errno.h>
		#include <libavb_user/libavb_user.h>
		#include <stdio.h>

		#include <android-base/file.h>
		#include <android-base/logging.h>
		#include <android-base/properties.h>
		#include <fs_mgr_overlayfs.h>
		#include <log/log_properties.h>
		#include <libavb_user/libavb_user.h>

		using namespace std::string_literals;

		namespace {

		#ifdef ALLOW_DISABLE_VERITY
		static const bool kAllowDisableVerity = true;
		const bool kAllowDisableVerity = true;
		#else
		static const bool kAllowDisableVerity = false;
		const bool kAllowDisableVerity = false;
		#endif

		static void suggest_run_adb_root() {
		if (getuid() != 0) printf("Maybe run adb root?\n");
		}

		/* 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.
		*/
		static std::string get_ab_suffix() {
		std::string get_ab_suffix() {
		return android::base::GetProperty("ro.boot.slot_suffix", "");
		}

		static bool is_avb_device_locked() {
		bool is_avb_device_locked() {
		return android::base::GetProperty("ro.boot.vbmeta.device_state", "") == "locked";
		}

		static bool overlayfs_setup(bool enable) {
		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();
		}

		bool overlayfs_setup(bool enable) {
		auto change = false;
		errno = 0;
		if (enable ? fs_mgr_overlayfs_teardown(nullptr, &change)
		: fs_mgr_overlayfs_setup(nullptr, nullptr, &change)) {
		if (change) {
		printf("%s overlayfs\n", enable ? "disabling" : "using");
		LOG(INFO) << (enable ? "disabling" : "using") << " overlayfs";
		}
		} else if (errno) {
		printf("Overlayfs %s failed with error %s\n", enable ? "teardown" : "setup", strerror(errno));
		suggest_run_adb_root();
		PLOG(ERROR) << "Failed to " << (enable ? "teardown" : "setup") << " overlayfs";
		}
		return change;
		}

		/* Use AVB to turn verity on/off */
		static bool set_avb_verity_enabled_state(AvbOps* ops, bool enable_verity) {
		bool set_avb_verity_enabled_state(AvbOps* ops, bool enable_verity) {
		std::string ab_suffix = get_ab_suffix();
		bool verity_enabled;

		if (is_avb_device_locked()) {
		printf("Device is locked. Please unlock the device first\n");
		LOG(ERROR) << "Device is locked. Please unlock the device first";
		return false;
		}

		if (!avb_user_verity_get(ops, ab_suffix.c_str(), &verity_enabled)) {
		printf("Error getting verity state. Try adb root first?\n");
		LOG(ERROR) << "Error getting verity state";
		return false;
		}

		if ((verity_enabled && enable_verity) \|\| (!verity_enabled && !enable_verity)) {
		printf("verity is already %s\n", verity_enabled ? "enabled" : "disabled");
		LOG(INFO) << "verity is already " << (verity_enabled ? "enabled" : "disabled");
		return false;
		}

		if (!avb_user_verity_set(ops, ab_suffix.c_str(), enable_verity)) {
		printf("Error setting verity\n");
		LOG(ERROR) << "Error setting verity state";
		return false;
		}

		printf("Successfully %s verity\n", enable_verity ? "enabled" : "disabled");
		LOG(INFO) << "Successfully " << (enable_verity ? "enabled" : "disabled") << " verity";
		return true;
		}

		void MyLogger(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 (severity == android::base::ERROR \|\| message[0] != '[') {
		fprintf(stderr, "%s\n", message);
		}
		static auto logd = android::base::LogdLogger();
		logd(id, severity, tag, file, line, message);
		}

		} // namespace

		int main(int argc, char* argv[]) {
		android::base::InitLogging(argv, MyLogger);

		if (argc == 0) {
		LOG(FATAL) << "set-verity-state called with empty argv";
		}
		@@ -110,44 +130,30 @@ int main(int argc, char* argv[]) {
		return 1;
		}

		// 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).
		bool using_avb = !android::base::GetProperty("ro.boot.vbmeta.digest", "").empty();

		// If using AVB, dm-verity is used on any build so we want it to
		// be possible to disable/enable on any build (except USER). For
		// VB1.0 dm-verity is only enabled on certain builds.
		if (!using_avb) {
		if (!kAllowDisableVerity) {
		printf("%s only works for userdebug builds\n", argv[0]);
		if (!kAllowDisableVerity \|\| !is_debuggable()) {
		errno = EPERM;
		PLOG(ERROR) << "Cannot disable/enable verity on user build";
		return 1;
		}

		if (!android::base::GetBoolProperty("ro.secure", false)) {
		overlayfs_setup(enable);
		printf("verity not enabled - ENG build\n");
		return 0;
		}
		if (getuid() != 0) {
		errno = EACCES;
		PLOG(ERROR) << "Must be running as root (adb root)";
		return 1;
		}

		// Should never be possible to disable dm-verity on a USER build
		// regardless of using AVB or VB1.0.
		if (!__android_log_is_debuggable()) {
		printf("verity cannot be disabled/enabled - USER build\n");
		return 0;
		if (!is_using_avb()) {
		LOG(ERROR) << "Expected AVB device, VB1.0 is no longer supported";
		return 1;
		}

		bool any_changed = false;
		if (using_avb) {
		// Yep, the system is using AVB.
		AvbOps* ops = avb_ops_user_new();
		if (ops == nullptr) {
		printf("Error getting AVB ops\n");
		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 1;
		}
		any_changed \|= set_avb_verity_enabled_state(ops, enable);
		avb_ops_user_free(ops);
		}

		bool any_changed = set_avb_verity_enabled_state(ops.get(), enable);
		any_changed \|= overlayfs_setup(enable);

		if (any_changed) {