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/*
* Copyright (C) 2017 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 "CheckEncryption.h"
#include "FileDeviceUtils.h"
#include "Utils.h"
#include "VolumeManager.h"
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
#include <cutils/iosched_policy.h>
#include <private/android_filesystem_config.h>
#include <sstream>
#include <sys/resource.h>
#include <sys/time.h>
#include <unistd.h>
#include <assert.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
using android::base::unique_fd;
using android::base::ReadFileToString;
using android::base::WriteStringToFile;
namespace android {
namespace vold {
constexpr uint32_t max_extents = 32;
constexpr size_t bytecount = 8;
constexpr int repeats = 256;
bool check_file(const std::string& needle) {
LOG(DEBUG) << "checkEncryption check_file: " << needle;
auto haystack = android::vold::BlockDeviceForPath(needle);
if (haystack.empty()) {
LOG(ERROR) << "Failed to find device for path: " << needle;
return false;
}
std::string randombytes;
if (ReadRandomBytes(bytecount, randombytes) != 0) {
LOG(ERROR) << "Failed to read random bytes";
return false;
}
std::string randomhex;
StrToHex(randombytes, randomhex);
std::ostringstream os;
for (int i = 0; i < repeats; i++) os << randomhex;
auto towrite = os.str();
if (access(needle.c_str(), F_OK) == 0) {
if (unlink(needle.c_str()) != 0) {
PLOG(ERROR) << "Failed to unlink " << needle;
return false;
}
}
LOG(DEBUG) << "Writing to " << needle;
if (!WriteStringToFile(towrite, needle)) {
PLOG(ERROR) << "Failed to write " << needle;
return false;
}
sync();
unique_fd haystack_fd(open(haystack.c_str(), O_RDONLY | O_CLOEXEC));
if (haystack_fd.get() == -1) {
PLOG(ERROR) << "Failed to open " << haystack;
return false;
}
auto fiemap = PathFiemap(needle, max_extents);
std::string area;
for (uint32_t i = 0; i < fiemap->fm_mapped_extents; i++) {
auto xt = &(fiemap->fm_extents[i]);
LOG(DEBUG) << "Extent " << i << " at " << xt->fe_physical << " length " << xt->fe_length;
if (lseek64(haystack_fd.get(), xt->fe_physical, SEEK_SET) == -1) {
PLOG(ERROR) << "Failed lseek";
return false;
}
auto toread = xt->fe_length;
while (toread > 0) {
char buf[BUFSIZ];
size_t wlen =
static_cast<size_t>(std::min(static_cast<typeof(toread)>(sizeof(buf)), toread));
auto l = read(haystack_fd.get(), buf, wlen);
if (l < 1) {
PLOG(ERROR) << "Failed read";
if (errno != EINTR) {
return false;
}
}
area.append(buf, l);
toread -= l;
}
}
LOG(DEBUG) << "Searching " << area.size() << " bytes of " << needle;
LOG(DEBUG) << "First position of blob: " << area.find(randomhex);
return true;
}
int CheckEncryption(const std::string& path) {
auto deNeedle(path);
deNeedle += "/misc";
if (android::vold::PrepareDir(deNeedle, 01771, AID_SYSTEM, AID_MISC)) {
return -1;
}
deNeedle += "/vold";
if (android::vold::PrepareDir(deNeedle, 0700, AID_ROOT, AID_ROOT)) {
return -1;
}
deNeedle += "/checkEncryption";
auto neNeedle(path);
neNeedle += "/unencrypted/checkEncryption";
check_file(deNeedle);
check_file(neNeedle);
return 0;
}
} // namespace vold
} // namespace android
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