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/*
* Copyright (C) 2014 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.
*/
#define TRACE_TAG ADB
#include "sysdeps.h"
#include <fcntl.h>
#include <inttypes.h>
#include <libavb_user/libavb_user.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/stat.h>
#include "android-base/properties.h"
#include "android-base/stringprintf.h"
#include <log/log_properties.h>
#include "adb.h"
#include "adb_io.h"
#include "adb_unique_fd.h"
#include "fs_mgr.h"
#include "remount_service.h"
#include "fec/io.h"
struct fstab *fstab;
#ifdef ALLOW_ADBD_DISABLE_VERITY
static const bool kAllowDisableVerity = true;
#else
static const bool kAllowDisableVerity = false;
#endif
/* Turn verity on/off */
static bool set_verity_enabled_state(int fd, const char* block_device, const char* mount_point,
bool enable) {
if (!make_block_device_writable(block_device)) {
WriteFdFmt(fd, "Could not make block device %s writable (%s).\n",
block_device, strerror(errno));
return false;
}
fec::io fh(block_device, O_RDWR);
if (!fh) {
WriteFdFmt(fd, "Could not open block device %s (%s).\n", block_device, strerror(errno));
WriteFdFmt(fd, "Maybe run adb root?\n");
return false;
}
fec_verity_metadata metadata;
if (!fh.get_verity_metadata(metadata)) {
WriteFdFmt(fd, "Couldn't find verity metadata!\n");
return false;
}
if (!enable && metadata.disabled) {
WriteFdFmt(fd, "Verity already disabled on %s\n", mount_point);
return false;
}
if (enable && !metadata.disabled) {
WriteFdFmt(fd, "Verity already enabled on %s\n", mount_point);
return false;
}
if (!fh.set_verity_status(enable)) {
WriteFdFmt(fd, "Could not set verity %s flag on device %s with error %s\n",
enable ? "enabled" : "disabled",
block_device, strerror(errno));
return false;
}
WriteFdFmt(fd, "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.
*
* Note that since sometime in O androidboot.slot_suffix is deprecated
* and androidboot.slot should be used instead. Since bootloaders may
* be out of sync with the OS, we check both and for extra safety
* prepend a leading underscore if there isn't one already.
*/
static std::string get_ab_suffix() {
std::string ab_suffix = android::base::GetProperty("ro.boot.slot_suffix", "");
if (ab_suffix == "") {
ab_suffix = android::base::GetProperty("ro.boot.slot", "");
}
if (ab_suffix.size() > 0 && ab_suffix[0] != '_') {
ab_suffix = std::string("_") + ab_suffix;
}
return ab_suffix;
}
/* Use AVB to turn verity on/off */
static bool set_avb_verity_enabled_state(int fd, AvbOps* ops, bool enable_verity) {
std::string ab_suffix = get_ab_suffix();
bool verity_enabled;
if (!avb_user_verity_get(ops, ab_suffix.c_str(), &verity_enabled)) {
WriteFdFmt(fd, "Error getting verity state\n");
return false;
}
if ((verity_enabled && enable_verity) || (!verity_enabled && !enable_verity)) {
WriteFdFmt(fd, "verity is already %s\n", verity_enabled ? "enabled" : "disabled");
return false;
}
if (!avb_user_verity_set(ops, ab_suffix.c_str(), enable_verity)) {
WriteFdFmt(fd, "Error setting verity\n");
return false;
}
WriteFdFmt(fd, "Successfully %s verity\n", enable_verity ? "enabled" : "disabled");
return true;
}
void set_verity_enabled_state_service(int fd, void* cookie) {
unique_fd closer(fd);
bool any_changed = false;
bool enable = (cookie != NULL);
// 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) {
WriteFdFmt(fd, "%s-verity only works for userdebug builds\n",
enable ? "enable" : "disable");
}
if (!android::base::GetBoolProperty("ro.secure", false)) {
WriteFdFmt(fd, "verity not enabled - ENG build\n");
return;
}
}
// Should never be possible to disable dm-verity on a USER build
// regardless of using AVB or VB1.0.
if (!__android_log_is_debuggable()) {
WriteFdFmt(fd, "verity cannot be disabled/enabled - USER build\n");
return;
}
if (using_avb) {
// Yep, the system is using AVB.
AvbOps* ops = avb_ops_user_new();
if (ops == nullptr) {
WriteFdFmt(fd, "Error getting AVB ops\n");
return;
}
if (set_avb_verity_enabled_state(fd, 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
fstab = fs_mgr_read_fstab_default();
if (!fstab) {
WriteFdFmt(fd, "Failed to read fstab\nMaybe run adb root?\n");
return;
}
// Loop through entries looking for ones that vold manages.
for (int i = 0; i < fstab->num_entries; i++) {
if (fs_mgr_is_verified(&fstab->recs[i])) {
if (set_verity_enabled_state(fd, fstab->recs[i].blk_device,
fstab->recs[i].mount_point, enable)) {
any_changed = true;
}
}
}
}
if (any_changed) {
WriteFdFmt(fd, "Now reboot your device for settings to take effect\n");
}
}
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