Move enable-verity/disable-verity out of adb to a helper binary.
Test: adb enable-verity
Test: adb disable-verity
Test: adb shell enable-verity
Test: adb shell disable-verity
Test: fs_mgr/tests/adb-remount-test.sh
Change-Id: I0f21a6678b332cc9166d912aa38952d50d924566
diff --git a/set-verity-state/set-verity-state.cpp b/set-verity-state/set-verity-state.cpp
new file mode 100644
index 0000000..0a26aba
--- /dev/null
+++ b/set-verity-state/set-verity-state.cpp
@@ -0,0 +1,274 @@
+/*
+ * 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 <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <libavb_user/libavb_user.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <fs_mgr.h>
+#include <fs_mgr_overlayfs.h>
+#include <fstab/fstab.h>
+#include <log/log_properties.h>
+
+#include "fec/io.h"
+
+#ifdef ALLOW_DISABLE_VERITY
+static const bool kAllowDisableVerity = true;
+#else
+static const bool kAllowDisableVerity = false;
+#endif
+
+using android::base::unique_fd;
+
+static void suggest_run_adb_root() {
+ if (getuid() != 0) printf("Maybe run adb root?\n");
+}
+
+static bool make_block_device_writable(const std::string& dev) {
+ unique_fd fd(open(dev.c_str(), O_RDONLY | O_CLOEXEC));
+ if (fd == -1) {
+ return false;
+ }
+
+ int OFF = 0;
+ bool result = (ioctl(fd.get(), BLKROSET, &OFF) != -1);
+ return result;
+}
+
+/* Turn verity on/off */
+static bool set_verity_enabled_state(const char* block_device, const char* mount_point,
+ bool enable) {
+ if (!make_block_device_writable(block_device)) {
+ printf("Could not make block device %s writable (%s).\n", block_device, strerror(errno));
+ return false;
+ }
+
+ fec::io fh(block_device, O_RDWR);
+
+ if (!fh) {
+ printf("Could not open block device %s (%s).\n", block_device, strerror(errno));
+ suggest_run_adb_root();
+ return false;
+ }
+
+ fec_verity_metadata metadata;
+
+ if (!fh.get_verity_metadata(metadata)) {
+ printf("Couldn't find verity metadata!\n");
+ return false;
+ }
+
+ if (!enable && metadata.disabled) {
+ printf("Verity already disabled on %s\n", mount_point);
+ return false;
+ }
+
+ if (enable && !metadata.disabled) {
+ printf("Verity already enabled on %s\n", mount_point);
+ return false;
+ }
+
+ if (!fh.set_verity_status(enable)) {
+ printf("Could not set verity %s flag on device %s with error %s\n",
+ enable ? "enabled" : "disabled", block_device, strerror(errno));
+ return false;
+ }
+
+ auto change = false;
+ errno = 0;
+ if (enable ? fs_mgr_overlayfs_teardown(mount_point, &change)
+ : fs_mgr_overlayfs_setup(nullptr, mount_point, &change)) {
+ if (change) {
+ printf("%s overlayfs for %s\n", enable ? "disabling" : "using", mount_point);
+ }
+ } else if (errno) {
+ int expected_errno = enable ? EBUSY : ENOENT;
+ if (errno != expected_errno) {
+ printf("Overlayfs %s for %s failed with error %s\n", enable ? "teardown" : "setup",
+ mount_point, strerror(errno));
+ }
+ }
+ printf("Verity %s on %s\n", enable ? "enabled" : "disabled", mount_point);
+ return true;
+}
+
+/* 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() {
+ return android::base::GetProperty("ro.boot.slot_suffix", "");
+}
+
+static bool is_avb_device_locked() {
+ return android::base::GetProperty("ro.boot.vbmeta.device_state", "") == "locked";
+}
+
+static 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");
+ }
+ } else if (errno) {
+ printf("Overlayfs %s failed with error %s\n", enable ? "teardown" : "setup", strerror(errno));
+ suggest_run_adb_root();
+ }
+ return change;
+}
+
+/* Use AVB to turn verity on/off */
+static 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");
+ return false;
+ }
+
+ if (!avb_user_verity_get(ops, ab_suffix.c_str(), &verity_enabled)) {
+ printf("Error getting verity state. Try adb root first?\n");
+ return false;
+ }
+
+ if ((verity_enabled && enable_verity) || (!verity_enabled && !enable_verity)) {
+ printf("verity is already %s\n", verity_enabled ? "enabled" : "disabled");
+ return false;
+ }
+
+ if (!avb_user_verity_set(ops, ab_suffix.c_str(), enable_verity)) {
+ printf("Error setting verity\n");
+ return false;
+ }
+
+ overlayfs_setup(enable_verity);
+ printf("Successfully %s verity\n", enable_verity ? "enabled" : "disabled");
+ return true;
+}
+
+int main(int argc, char* argv[]) {
+ if (argc == 0) {
+ LOG(FATAL) << "set-verity-state called with empty argv";
+ }
+
+ std::optional<bool> enable_opt;
+ std::string procname = android::base::Basename(argv[0]);
+ if (procname == "enable-verity") {
+ enable_opt = true;
+ } else if (procname == "disable-verity") {
+ enable_opt = false;
+ }
+
+ if (!enable_opt.has_value()) {
+ if (argc != 2) {
+ printf("usage: %s [1|0]\n", argv[0]);
+ return 1;
+ }
+
+ if (strcmp(argv[1], "1") == 0) {
+ enable_opt = true;
+ } else if (strcmp(argv[1], "0") == 0) {
+ enable_opt = false;
+ } else {
+ printf("usage: %s [1|0]\n", argv[0]);
+ return 1;
+ }
+ }
+
+ bool enable = enable_opt.value();
+
+ bool any_changed = false;
+
+ // 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 (!android::base::GetBoolProperty("ro.secure", false)) {
+ overlayfs_setup(enable);
+ printf("verity not enabled - ENG build\n");
+ return 0;
+ }
+ }
+
+ // 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 (using_avb) {
+ // Yep, the system is using AVB.
+ AvbOps* ops = avb_ops_user_new();
+ if (ops == nullptr) {
+ printf("Error getting AVB ops\n");
+ return 1;
+ }
+ if (set_avb_verity_enabled_state(ops, enable)) {
+ any_changed = true;
+ }
+ avb_ops_user_free(ops);
+ } else {
+ // Not using AVB - assume VB1.0.
+
+ // read all fstab entries at once from all sources
+ android::fs_mgr::Fstab fstab;
+ if (!android::fs_mgr::ReadDefaultFstab(&fstab)) {
+ printf("Failed to read fstab\n");
+ suggest_run_adb_root();
+ return 0;
+ }
+
+ // Loop through entries looking for ones that verity manages.
+ for (const auto& entry : fstab) {
+ if (entry.fs_mgr_flags.verify) {
+ if (set_verity_enabled_state(entry.blk_device.c_str(), entry.mount_point.c_str(), enable)) {
+ any_changed = true;
+ }
+ }
+ }
+ }
+ if (!any_changed) any_changed = overlayfs_setup(enable);
+
+ if (any_changed) {
+ printf("Now reboot your device for settings to take effect\n");
+ }
+
+ return 0;
+}