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platform_system_vold/model/Disk.cpp
Paul Crowley 4eac264727 Refactor key generation to handle both normal and metadata encryption. 
Bug: 147733587
Test: Treehugger
Change-Id: Iee176037dec2621c84da325c2627f988fcebbc8d
Merged-In: Iee176037dec2621c84da325c2627f988fcebbc8d
2020-02-14 13:59:06 -08:00

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/*
* Copyright (C) 2015 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 "Disk.h"
#include "FsCrypt.h"
#include "KeyUtil.h"
#include "PrivateVolume.h"
#include "PublicVolume.h"
#include "Utils.h"
#include "VolumeBase.h"
#include "VolumeManager.h"
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <fscrypt/fscrypt.h>
#include "cryptfs.h"
#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <vector>
using android::base::ReadFileToString;
using android::base::StringPrintf;
using android::base::WriteStringToFile;
namespace android {
namespace vold {
static const char* kSgdiskPath = "/system/bin/sgdisk";
static const char* kSgdiskToken = " \t\n";
static const char* kSysfsLoopMaxMinors = "/sys/module/loop/parameters/max_part";
static const char* kSysfsMmcMaxMinorsDeprecated = "/sys/module/mmcblk/parameters/perdev_minors";
static const char* kSysfsMmcMaxMinors = "/sys/module/mmc_block/parameters/perdev_minors";
static const unsigned int kMajorBlockLoop = 7;
static const unsigned int kMajorBlockScsiA = 8;
static const unsigned int kMajorBlockScsiB = 65;
static const unsigned int kMajorBlockScsiC = 66;
static const unsigned int kMajorBlockScsiD = 67;
static const unsigned int kMajorBlockScsiE = 68;
static const unsigned int kMajorBlockScsiF = 69;
static const unsigned int kMajorBlockScsiG = 70;
static const unsigned int kMajorBlockScsiH = 71;
static const unsigned int kMajorBlockScsiI = 128;
static const unsigned int kMajorBlockScsiJ = 129;
static const unsigned int kMajorBlockScsiK = 130;
static const unsigned int kMajorBlockScsiL = 131;
static const unsigned int kMajorBlockScsiM = 132;
static const unsigned int kMajorBlockScsiN = 133;
static const unsigned int kMajorBlockScsiO = 134;
static const unsigned int kMajorBlockScsiP = 135;
static const unsigned int kMajorBlockMmc = 179;
static const unsigned int kMajorBlockExperimentalMin = 240;
static const unsigned int kMajorBlockExperimentalMax = 254;
static const unsigned int kMajorBlockDynamicMin = 234;
static const unsigned int kMajorBlockDynamicMax = 512;
static const char* kGptBasicData = "EBD0A0A2-B9E5-4433-87C0-68B6B72699C7";
static const char* kGptAndroidMeta = "19A710A2-B3CA-11E4-B026-10604B889DCF";
static const char* kGptAndroidExpand = "193D1EA4-B3CA-11E4-B075-10604B889DCF";
enum class Table {
kUnknown,
kMbr,
kGpt,
};
static bool isVirtioBlkDevice(unsigned int major) {
/*
* The new emulator's "ranchu" virtual board no longer includes a goldfish
* MMC-based SD card device; instead, it emulates SD cards with virtio-blk,
* which has been supported by upstream kernel and QEMU for quite a while.
* Unfortunately, the virtio-blk block device driver does not use a fixed
* major number, but relies on the kernel to assign one from a specific
* range of block majors, which are allocated for "LOCAL/EXPERIMENAL USE"
* per Documentation/devices.txt. This is true even for the latest Linux
* kernel (4.4; see init() in drivers/block/virtio_blk.c).
*
* This makes it difficult for vold to detect a virtio-blk based SD card.
* The current solution checks two conditions (both must be met):
*
* a) If the running environment is the emulator;
* b) If the major number is an experimental block device major number (for
* x86/x86_64 3.10 ranchu kernels, virtio-blk always gets major number
* 253, but it is safer to match the range than just one value).
*
* Other conditions could be used, too, e.g. the hardware name should be
* "ranchu", the device's sysfs path should end with "/block/vd[d-z]", etc.
* But just having a) and b) is enough for now.
*/
return IsRunningInEmulator() && major >= kMajorBlockExperimentalMin &&
major <= kMajorBlockExperimentalMax;
}
static bool isNvmeBlkDevice(unsigned int major, const std::string& sysPath) {
return sysPath.find("nvme") != std::string::npos && major >= kMajorBlockDynamicMin &&
major <= kMajorBlockDynamicMax;
}
Disk::Disk(const std::string& eventPath, dev_t device, const std::string& nickname, int flags)
: mDevice(device),
mSize(-1),
mNickname(nickname),
mFlags(flags),
mCreated(false),
mJustPartitioned(false) {
mId = StringPrintf("disk:%u,%u", major(device), minor(device));
mEventPath = eventPath;
mSysPath = StringPrintf("/sys/%s", eventPath.c_str());
mDevPath = StringPrintf("/dev/block/vold/%s", mId.c_str());
CreateDeviceNode(mDevPath, mDevice);
}
Disk::~Disk() {
CHECK(!mCreated);
DestroyDeviceNode(mDevPath);
}
std::shared_ptr<VolumeBase> Disk::findVolume(const std::string& id) {
for (auto vol : mVolumes) {
if (vol->getId() == id) {
return vol;
}
auto stackedVol = vol->findVolume(id);
if (stackedVol != nullptr) {
return stackedVol;
}
}
return nullptr;
}
void Disk::listVolumes(VolumeBase::Type type, std::list<std::string>& list) const {
for (const auto& vol : mVolumes) {
if (vol->getType() == type) {
list.push_back(vol->getId());
}
// TODO: consider looking at stacked volumes
}
}
status_t Disk::create() {
CHECK(!mCreated);
mCreated = true;
auto listener = VolumeManager::Instance()->getListener();
if (listener) listener->onDiskCreated(getId(), mFlags);
readMetadata();
readPartitions();
return OK;
}
status_t Disk::destroy() {
CHECK(mCreated);
destroyAllVolumes();
mCreated = false;
auto listener = VolumeManager::Instance()->getListener();
if (listener) listener->onDiskDestroyed(getId());
return OK;
}
void Disk::createPublicVolume(dev_t device) {
auto vol = std::shared_ptr<VolumeBase>(new PublicVolume(device));
if (mJustPartitioned) {
LOG(DEBUG) << "Device just partitioned; silently formatting";
vol->setSilent(true);
vol->create();
vol->format("auto");
vol->destroy();
vol->setSilent(false);
}
mVolumes.push_back(vol);
vol->setDiskId(getId());
vol->create();
}
void Disk::createPrivateVolume(dev_t device, const std::string& partGuid) {
std::string normalizedGuid;
if (NormalizeHex(partGuid, normalizedGuid)) {
LOG(WARNING) << "Invalid GUID " << partGuid;
return;
}
std::string keyRaw;
if (!ReadFileToString(BuildKeyPath(normalizedGuid), &keyRaw)) {
PLOG(ERROR) << "Failed to load key for GUID " << normalizedGuid;
return;
}
LOG(DEBUG) << "Found key for GUID " << normalizedGuid;
auto keyBuffer = KeyBuffer(keyRaw.begin(), keyRaw.end());
auto vol = std::shared_ptr<VolumeBase>(new PrivateVolume(device, keyBuffer));
if (mJustPartitioned) {
LOG(DEBUG) << "Device just partitioned; silently formatting";
vol->setSilent(true);
vol->create();
vol->format("auto");
vol->destroy();
vol->setSilent(false);
}
mVolumes.push_back(vol);
vol->setDiskId(getId());
vol->setPartGuid(partGuid);
vol->create();
}
void Disk::destroyAllVolumes() {
for (const auto& vol : mVolumes) {
vol->destroy();
}
mVolumes.clear();
}
status_t Disk::readMetadata() {
mSize = -1;
mLabel.clear();
if (GetBlockDevSize(mDevPath, &mSize) != OK) {
mSize = -1;
}
unsigned int majorId = major(mDevice);
switch (majorId) {
case kMajorBlockLoop: {
mLabel = "Virtual";
break;
}
// clang-format off
case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC:
case kMajorBlockScsiD: case kMajorBlockScsiE: case kMajorBlockScsiF:
case kMajorBlockScsiG: case kMajorBlockScsiH: case kMajorBlockScsiI:
case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
case kMajorBlockScsiM: case kMajorBlockScsiN: case kMajorBlockScsiO:
case kMajorBlockScsiP: {
// clang-format on
std::string path(mSysPath + "/device/vendor");
std::string tmp;
if (!ReadFileToString(path, &tmp)) {
PLOG(WARNING) << "Failed to read vendor from " << path;
return -errno;
}
tmp = android::base::Trim(tmp);
mLabel = tmp;
break;
}
case kMajorBlockMmc: {
std::string path(mSysPath + "/device/manfid");
std::string tmp;
if (!ReadFileToString(path, &tmp)) {
PLOG(WARNING) << "Failed to read manufacturer from " << path;
return -errno;
}
tmp = android::base::Trim(tmp);
int64_t manfid;
if (!android::base::ParseInt(tmp, &manfid)) {
PLOG(WARNING) << "Failed to parse manufacturer " << tmp;
return -EINVAL;
}
// Our goal here is to give the user a meaningful label, ideally
// matching whatever is silk-screened on the card. To reduce
// user confusion, this list doesn't contain white-label manfid.
switch (manfid) {
// clang-format off
case 0x000003: mLabel = "SanDisk"; break;
case 0x00001b: mLabel = "Samsung"; break;
case 0x000028: mLabel = "Lexar"; break;
case 0x000074: mLabel = "Transcend"; break;
// clang-format on
}
break;
}
default: {
if (isVirtioBlkDevice(majorId)) {
LOG(DEBUG) << "Recognized experimental block major ID " << majorId
<< " as virtio-blk (emulator's virtual SD card device)";
mLabel = "Virtual";
break;
}
if (isNvmeBlkDevice(majorId, mSysPath)) {
std::string path(mSysPath + "/device/model");
std::string tmp;
if (!ReadFileToString(path, &tmp)) {
PLOG(WARNING) << "Failed to read vendor from " << path;
return -errno;
}
mLabel = tmp;
break;
}
LOG(WARNING) << "Unsupported block major type " << majorId;
return -ENOTSUP;
}
}
auto listener = VolumeManager::Instance()->getListener();
if (listener) listener->onDiskMetadataChanged(getId(), mSize, mLabel, mSysPath);
return OK;
}
status_t Disk::readPartitions() {
int maxMinors = getMaxMinors();
if (maxMinors < 0) {
return -ENOTSUP;
}
destroyAllVolumes();
// Parse partition table
std::vector<std::string> cmd;
cmd.push_back(kSgdiskPath);
cmd.push_back("--android-dump");
cmd.push_back(mDevPath);
std::vector<std::string> output;
status_t res = ForkExecvp(cmd, &output);
if (res != OK) {
LOG(WARNING) << "sgdisk failed to scan " << mDevPath;
auto listener = VolumeManager::Instance()->getListener();
if (listener) listener->onDiskScanned(getId());
mJustPartitioned = false;
return res;
}
Table table = Table::kUnknown;
bool foundParts = false;
for (const auto& line : output) {
auto split = android::base::Split(line, kSgdiskToken);
auto it = split.begin();
if (it == split.end()) continue;
if (*it == "DISK") {
if (++it == split.end()) continue;
if (*it == "mbr") {
table = Table::kMbr;
} else if (*it == "gpt") {
table = Table::kGpt;
} else {
LOG(WARNING) << "Invalid partition table " << *it;
continue;
}
} else if (*it == "PART") {
foundParts = true;
if (++it == split.end()) continue;
int i = 0;
if (!android::base::ParseInt(*it, &i, 1, maxMinors)) {
LOG(WARNING) << "Invalid partition number " << *it;
continue;
}
dev_t partDevice = makedev(major(mDevice), minor(mDevice) + i);
if (table == Table::kMbr) {
if (++it == split.end()) continue;
int type = 0;
if (!android::base::ParseInt("0x" + *it, &type)) {
LOG(WARNING) << "Invalid partition type " << *it;
continue;
}
switch (type) {
case 0x06: // FAT16
case 0x07: // HPFS/NTFS/exFAT
case 0x0b: // W95 FAT32 (LBA)
case 0x0c: // W95 FAT32 (LBA)
case 0x0e: // W95 FAT16 (LBA)
createPublicVolume(partDevice);
break;
}
} else if (table == Table::kGpt) {
if (++it == split.end()) continue;
auto typeGuid = *it;
if (++it == split.end()) continue;
auto partGuid = *it;
if (android::base::EqualsIgnoreCase(typeGuid, kGptBasicData)) {
createPublicVolume(partDevice);
} else if (android::base::EqualsIgnoreCase(typeGuid, kGptAndroidExpand)) {
createPrivateVolume(partDevice, partGuid);
}
}
}
}
// Ugly last ditch effort, treat entire disk as partition
if (table == Table::kUnknown || !foundParts) {
LOG(WARNING) << mId << " has unknown partition table; trying entire device";
std::string fsType;
std::string unused;
if (ReadMetadataUntrusted(mDevPath, &fsType, &unused, &unused) == OK) {
createPublicVolume(mDevice);
} else {
LOG(WARNING) << mId << " failed to identify, giving up";
}
}
auto listener = VolumeManager::Instance()->getListener();
if (listener) listener->onDiskScanned(getId());
mJustPartitioned = false;
return OK;
}
status_t Disk::unmountAll() {
for (const auto& vol : mVolumes) {
vol->unmount();
}
return OK;
}
status_t Disk::partitionPublic() {
int res;
destroyAllVolumes();
mJustPartitioned = true;
// First nuke any existing partition table
std::vector<std::string> cmd;
cmd.push_back(kSgdiskPath);
cmd.push_back("--zap-all");
cmd.push_back(mDevPath);
// Zap sometimes returns an error when it actually succeeded, so
// just log as warning and keep rolling forward.
if ((res = ForkExecvp(cmd)) != 0) {
LOG(WARNING) << "Failed to zap; status " << res;
}
// Now let's build the new MBR table. We heavily rely on sgdisk to
// force optimal alignment on the created partitions.
cmd.clear();
cmd.push_back(kSgdiskPath);
cmd.push_back("--new=0:0:-0");
cmd.push_back("--typecode=0:0c00");
cmd.push_back("--gpttombr=1");
cmd.push_back(mDevPath);
if ((res = ForkExecvp(cmd)) != 0) {
LOG(ERROR) << "Failed to partition; status " << res;
return res;
}
return OK;
}
status_t Disk::partitionPrivate() {
return partitionMixed(0);
}
status_t Disk::partitionMixed(int8_t ratio) {
int res;
destroyAllVolumes();
mJustPartitioned = true;
// First nuke any existing partition table
std::vector<std::string> cmd;
cmd.push_back(kSgdiskPath);
cmd.push_back("--zap-all");
cmd.push_back(mDevPath);
// Zap sometimes returns an error when it actually succeeded, so
// just log as warning and keep rolling forward.
if ((res = ForkExecvp(cmd)) != 0) {
LOG(WARNING) << "Failed to zap; status " << res;
}
// We've had some success above, so generate both the private partition
// GUID and encryption key and persist them.
std::string partGuidRaw;
if (GenerateRandomUuid(partGuidRaw) != OK) {
LOG(ERROR) << "Failed to generate GUID";
return -EIO;
}
KeyBuffer key;
if (!generateStorageKey(cryptfs_get_keygen(), &key)) {
LOG(ERROR) << "Failed to generate key";
return -EIO;
}
std::string keyRaw(key.begin(), key.end());
std::string partGuid;
StrToHex(partGuidRaw, partGuid);
if (!WriteStringToFile(keyRaw, BuildKeyPath(partGuid))) {
LOG(ERROR) << "Failed to persist key";
return -EIO;
} else {
LOG(DEBUG) << "Persisted key for GUID " << partGuid;
}
// Now let's build the new GPT table. We heavily rely on sgdisk to
// force optimal alignment on the created partitions.
cmd.clear();
cmd.push_back(kSgdiskPath);
// If requested, create a public partition first. Mixed-mode partitioning
// like this is an experimental feature.
if (ratio > 0) {
if (ratio < 10 || ratio > 90) {
LOG(ERROR) << "Mixed partition ratio must be between 10-90%";
return -EINVAL;
}
uint64_t splitMb = ((mSize / 100) * ratio) / 1024 / 1024;
cmd.push_back(StringPrintf("--new=0:0:+%" PRId64 "M", splitMb));
cmd.push_back(StringPrintf("--typecode=0:%s", kGptBasicData));
cmd.push_back("--change-name=0:shared");
}
// Define a metadata partition which is designed for future use; there
// should only be one of these per physical device, even if there are
// multiple private volumes.
cmd.push_back("--new=0:0:+16M");
cmd.push_back(StringPrintf("--typecode=0:%s", kGptAndroidMeta));
cmd.push_back("--change-name=0:android_meta");
// Define a single private partition filling the rest of disk.
cmd.push_back("--new=0:0:-0");
cmd.push_back(StringPrintf("--typecode=0:%s", kGptAndroidExpand));
cmd.push_back(StringPrintf("--partition-guid=0:%s", partGuid.c_str()));
cmd.push_back("--change-name=0:android_expand");
cmd.push_back(mDevPath);
if ((res = ForkExecvp(cmd)) != 0) {
LOG(ERROR) << "Failed to partition; status " << res;
return res;
}
return OK;
}
int Disk::getMaxMinors() {
// Figure out maximum partition devices supported
unsigned int majorId = major(mDevice);
switch (majorId) {
case kMajorBlockLoop: {
std::string tmp;
if (!ReadFileToString(kSysfsLoopMaxMinors, &tmp)) {
LOG(ERROR) << "Failed to read max minors";
return -errno;
}
return std::stoi(tmp);
}
// clang-format off
case kMajorBlockScsiA: case kMajorBlockScsiB: case kMajorBlockScsiC:
case kMajorBlockScsiD: case kMajorBlockScsiE: case kMajorBlockScsiF:
case kMajorBlockScsiG: case kMajorBlockScsiH: case kMajorBlockScsiI:
case kMajorBlockScsiJ: case kMajorBlockScsiK: case kMajorBlockScsiL:
case kMajorBlockScsiM: case kMajorBlockScsiN: case kMajorBlockScsiO:
case kMajorBlockScsiP: {
// clang-format on
// Per Documentation/devices.txt this is static
return 15;
}
case kMajorBlockMmc: {
// Per Documentation/devices.txt this is dynamic
std::string tmp;
if (!ReadFileToString(kSysfsMmcMaxMinors, &tmp) &&
!ReadFileToString(kSysfsMmcMaxMinorsDeprecated, &tmp)) {
LOG(ERROR) << "Failed to read max minors";
return -errno;
}
return std::stoi(tmp);
}
default: {
if (isVirtioBlkDevice(majorId)) {
// drivers/block/virtio_blk.c has "#define PART_BITS 4", so max is
// 2^4 - 1 = 15
return 15;
}
if (isNvmeBlkDevice(majorId, mSysPath)) {
// despite kernel nvme driver supports up to 1M minors,
// #define NVME_MINORS (1U << MINORBITS)
// sgdisk can not support more than 127 partitions, due to
// #define MAX_MBR_PARTS 128
return 127;
}
}
}
LOG(ERROR) << "Unsupported block major type " << majorId;
return -ENOTSUP;
}
} // namespace vold
} // namespace android
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