From 933828251d862bc24b888d247a1cb13573e7232b Mon Sep 17 00:00:00 2001 From: Ethan Yonker Date: Thu, 1 Nov 2018 15:25:31 -0500 Subject: Add metadata decrypt support for FBE Change-Id: Ie0292f4ffea5993a4ae74fa04fc5c8252ca2cfcf --- crypto/ext4crypt/MetadataCrypt.cpp | 271 +++++++++++++++++++++++++++++++++++++ 1 file changed, 271 insertions(+) create mode 100644 crypto/ext4crypt/MetadataCrypt.cpp (limited to 'crypto/ext4crypt/MetadataCrypt.cpp') diff --git a/crypto/ext4crypt/MetadataCrypt.cpp b/crypto/ext4crypt/MetadataCrypt.cpp new file mode 100644 index 000000000..b195fa09e --- /dev/null +++ b/crypto/ext4crypt/MetadataCrypt.cpp @@ -0,0 +1,271 @@ +/* + * Copyright (C) 2016 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 "KeyBuffer.h" +#include "MetadataCrypt.h" + +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#include + +//#include +#include +#include +#include +//#include + +//#include "EncryptInplace.h" +#include "KeyStorage4.h" +#include "KeyUtil.h" +//#include "secontext.h" +#include "Utils.h" +//#include "VoldUtil.h" + +#include +#define LOG(x) std::cout +#define PLOG(x) std::cout +#include + +#define DM_CRYPT_BUF_SIZE 4096 +#define TABLE_LOAD_RETRIES 10 +#define DEFAULT_KEY_TARGET_TYPE "default-key" + +using android::vold::KeyBuffer; + +static const std::string kDmNameUserdata = "userdata"; + +void get_blkdev_size(int fd, unsigned long* nr_sec) { + if ((ioctl(fd, BLKGETSIZE, nr_sec)) == -1) { + *nr_sec = 0; + } +} + +static const char* kLookup = "0123456789abcdef"; + +android::status_t StrToHex(const KeyBuffer& str, KeyBuffer& hex) { + hex.clear(); + for (size_t i = 0; i < str.size(); i++) { + hex.push_back(kLookup[(str.data()[i] & 0xF0) >> 4]); + hex.push_back(kLookup[str.data()[i] & 0x0F]); + } + return android::OK; +} + +/*static bool mount_via_fs_mgr(const char* mount_point, const char* blk_device) { + // fs_mgr_do_mount runs fsck. Use setexeccon to run trusted + // partitions in the fsck domain. + if (setexeccon(secontextFsck())) { + PLOG(ERROR) << "Failed to setexeccon"; + return false; + } + auto mount_rc = fs_mgr_do_mount(fstab_default, const_cast(mount_point), + const_cast(blk_device), nullptr); + if (setexeccon(nullptr)) { + PLOG(ERROR) << "Failed to clear setexeccon"; + return false; + } + if (mount_rc != 0) { + LOG(ERROR) << "fs_mgr_do_mount failed with rc " << mount_rc; + return false; + } + LOG(DEBUG) << "Mounted " << mount_point; + return true; +}*/ + +static bool read_key(const std::string& key_dir, bool create_if_absent, KeyBuffer* key) { + /*if (!data_rec->key_dir) { + LOG(ERROR) << "Failed to get key_dir"; + return false; + } + std::string key_dir = data_rec->key_dir;*/ + auto dir = key_dir + "/key"; + LOG(DEBUG) << "key_dir/key: " << dir << "\n"; + /*if (fs_mkdirs(dir.c_str(), 0700)) { + PLOG(ERROR) << "Creating directories: " << dir; + return false; + }*/ + auto temp = key_dir + "/tmp"; + if (!android::vold::retrieveKey(create_if_absent, dir, temp, key)) return false; + return true; +} + +static KeyBuffer default_key_params(const std::string& real_blkdev, const KeyBuffer& key) { + KeyBuffer hex_key; + if (/*android::vold::*/StrToHex(key, hex_key) != android::OK) { + LOG(ERROR) << "Failed to turn key to hex\n"; + return KeyBuffer(); + } + auto res = KeyBuffer() + "AES-256-XTS " + hex_key + " " + real_blkdev.c_str() + " 0"; + return res; +} + +static bool get_number_of_sectors(const std::string& real_blkdev, uint64_t *nr_sec) { + android::base::unique_fd dev_fd(TEMP_FAILURE_RETRY(open( + real_blkdev.c_str(), O_RDONLY | O_CLOEXEC, 0))); + if (dev_fd == -1) { + PLOG(ERROR) << "Unable to open " << real_blkdev << " to measure size\n"; + return false; + } + unsigned long res; + // TODO: should use BLKGETSIZE64 + get_blkdev_size(dev_fd.get(), &res); + if (res == 0) { + PLOG(ERROR) << "Unable to measure size of " << real_blkdev << "\n"; + return false; + } + *nr_sec = res; + return true; +} + +static struct dm_ioctl* dm_ioctl_init(char *buffer, size_t buffer_size, + const std::string& dm_name) { + if (buffer_size < sizeof(dm_ioctl)) { + LOG(ERROR) << "dm_ioctl buffer too small\n"; + return nullptr; + } + + memset(buffer, 0, buffer_size); + struct dm_ioctl* io = (struct dm_ioctl*) buffer; + io->data_size = buffer_size; + io->data_start = sizeof(struct dm_ioctl); + io->version[0] = 4; + io->version[1] = 0; + io->version[2] = 0; + io->flags = 0; + dm_name.copy(io->name, sizeof(io->name)); + return io; +} + +static bool create_crypto_blk_dev(const std::string& dm_name, uint64_t nr_sec, + const std::string& target_type, const KeyBuffer& crypt_params, + std::string* crypto_blkdev) { + PLOG(INFO) << "starting create_crypto_blk_dev\n"; + android::base::unique_fd dm_fd(TEMP_FAILURE_RETRY(open( + "/dev/device-mapper", O_RDWR | O_CLOEXEC, 0))); + if (dm_fd == -1) { + PLOG(ERROR) << "Cannot open device-mapper\n"; + return false; + } + alignas(struct dm_ioctl) char buffer[DM_CRYPT_BUF_SIZE]; + auto io = dm_ioctl_init(buffer, sizeof(buffer), dm_name); + if (!io || ioctl(dm_fd.get(), DM_DEV_CREATE, io) != 0) { + PLOG(ERROR) << "Cannot create dm-crypt device " << dm_name << "\n"; + return false; + } + + // Get the device status, in particular, the name of its device file + io = dm_ioctl_init(buffer, sizeof(buffer), dm_name); + if (ioctl(dm_fd.get(), DM_DEV_STATUS, io) != 0) { + PLOG(ERROR) << "Cannot retrieve dm-crypt device status " << dm_name << "\n"; + return false; + } + *crypto_blkdev = std::string() + "/dev/block/dm-" + std::to_string( + (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00)); + + io = dm_ioctl_init(buffer, sizeof(buffer), dm_name); + size_t paramix = io->data_start + sizeof(struct dm_target_spec); + size_t nullix = paramix + crypt_params.size(); + size_t endix = (nullix + 1 + 7) & 8; // Add room for \0 and align to 8 byte boundary + + if (endix > sizeof(buffer)) { + LOG(ERROR) << "crypt_params too big for DM_CRYPT_BUF_SIZE\n"; + return false; + } + + io->target_count = 1; + auto tgt = (struct dm_target_spec *) (buffer + io->data_start); + tgt->status = 0; + tgt->sector_start = 0; + tgt->length = nr_sec; + target_type.copy(tgt->target_type, sizeof(tgt->target_type)); + memcpy(buffer + paramix, crypt_params.data(), + std::min(crypt_params.size(), sizeof(buffer) - paramix)); + buffer[nullix] = '\0'; + tgt->next = endix; + + for (int i = 0; ; i++) { + if (ioctl(dm_fd.get(), DM_TABLE_LOAD, io) == 0) { + break; + } + if (i+1 >= TABLE_LOAD_RETRIES) { + PLOG(ERROR) << "DM_TABLE_LOAD ioctl failed\n"; + return false; + } + PLOG(INFO) << "DM_TABLE_LOAD ioctl failed, retrying\n"; + usleep(500000); + } + + // Resume this device to activate it + io = dm_ioctl_init(buffer, sizeof(buffer), dm_name); + if (ioctl(dm_fd.get(), DM_DEV_SUSPEND, io)) { + PLOG(ERROR) << "Cannot resume dm-crypt device " << dm_name << "\n"; + return false; + } + return true; +} + +bool e4crypt_mount_metadata_encrypted(const std::string& mount_point, bool needs_encrypt, const std::string& key_dir, const std::string& blk_device, std::string* crypto_blkdev) { + LOG(DEBUG) << "e4crypt_mount_metadata_encrypted: " << mount_point << " " << needs_encrypt << "\n"; + /*auto encrypted_state = android::base::GetProperty("ro.crypto.state", ""); + if (encrypted_state != "") { + LOG(DEBUG) << "e4crypt_enable_crypto got unexpected starting state: " << encrypted_state; + return false; + } + auto data_rec = fs_mgr_get_entry_for_mount_point(fstab_default, mount_point); + if (!data_rec) { + LOG(ERROR) << "Failed to get data_rec"; + return false; + }*/ + KeyBuffer key; + if (!read_key(key_dir, needs_encrypt, &key)) return false; + uint64_t nr_sec; + if (!get_number_of_sectors(blk_device, &nr_sec)) return false; + //std::string crypto_blkdev; + if (!create_crypto_blk_dev(kDmNameUserdata, nr_sec, DEFAULT_KEY_TARGET_TYPE, + default_key_params(blk_device, key), /*&*/crypto_blkdev)) + return false; + // FIXME handle the corrupt case + /*if (needs_encrypt) { + LOG(INFO) << "Beginning inplace encryption, nr_sec: " << nr_sec; + off64_t size_already_done = 0; + auto rc = + cryptfs_enable_inplace(const_cast(crypto_blkdev.c_str()), data_rec->blk_device, + nr_sec, &size_already_done, nr_sec, 0, false); + if (rc != 0) { + LOG(ERROR) << "Inplace crypto failed with code: " << rc; + return false; + } + if (static_cast(size_already_done) != nr_sec) { + LOG(ERROR) << "Inplace crypto only got up to sector: " << size_already_done; + return false; + } + LOG(INFO) << "Inplace encryption complete"; + } + + LOG(DEBUG) << "Mounting metadata-encrypted filesystem:" << mount_point; + mount_via_fs_mgr(data_rec->mount_point, crypto_blkdev.c_str());*/ + LOG(DEBUG) << "crypto block device '" << *crypto_blkdev << "\n"; + return true; +} -- cgit v1.2.3