2048a2865c
Bug: 36029169 Test: tested by hand on Taimen Change-Id: I5717a8630bb2c8d8fe5c343d519c4e59862ecbdf
149 lines
4.2 KiB
C++
149 lines
4.2 KiB
C++
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "CheckEncryption.h"
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#include "FileDeviceUtils.h"
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#include "Utils.h"
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#include "VolumeManager.h"
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#include <android-base/file.h>
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#include <android-base/logging.h>
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#include <android-base/unique_fd.h>
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#include <cutils/iosched_policy.h>
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#include <private/android_filesystem_config.h>
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#include <sstream>
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#include <sys/resource.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <linux/fs.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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using android::base::unique_fd;
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using android::base::ReadFileToString;
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using android::base::WriteStringToFile;
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namespace android {
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namespace vold {
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constexpr uint32_t max_extents = 32;
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constexpr size_t bytecount = 8;
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constexpr int repeats = 256;
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bool check_file(const std::string& needle) {
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LOG(DEBUG) << "checkEncryption check_file: " << needle;
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auto haystack = android::vold::BlockDeviceForPath(needle);
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if (haystack.empty()) {
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LOG(ERROR) << "Failed to find device for path: " << needle;
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return false;
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}
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std::string randombytes;
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if (ReadRandomBytes(bytecount, randombytes) != 0) {
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LOG(ERROR) << "Failed to read random bytes";
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return false;
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}
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std::string randomhex;
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StrToHex(randombytes, randomhex);
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std::ostringstream os;
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for (int i = 0; i < repeats; i++) os << randomhex;
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auto towrite = os.str();
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if (access(needle.c_str(), F_OK) == 0) {
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if (unlink(needle.c_str()) != 0) {
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PLOG(ERROR) << "Failed to unlink " << needle;
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return false;
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}
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}
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LOG(DEBUG) << "Writing to " << needle;
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if (!WriteStringToFile(towrite, needle)) {
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PLOG(ERROR) << "Failed to write " << needle;
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return false;
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}
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sync();
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unique_fd haystack_fd(open(haystack.c_str(), O_RDONLY | O_CLOEXEC));
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if (haystack_fd.get() == -1) {
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PLOG(ERROR) << "Failed to open " << haystack;
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return false;
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}
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auto fiemap = PathFiemap(needle, max_extents);
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std::string area;
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for (uint32_t i = 0; i < fiemap->fm_mapped_extents; i++) {
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auto xt = &(fiemap->fm_extents[i]);
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LOG(DEBUG) << "Extent " << i << " at " << xt->fe_physical << " length " << xt->fe_length;
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if (lseek64(haystack_fd.get(), xt->fe_physical, SEEK_SET) == -1) {
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PLOG(ERROR) << "Failed lseek";
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return false;
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}
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auto toread = xt->fe_length;
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while (toread > 0) {
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char buf[BUFSIZ];
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size_t wlen =
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static_cast<size_t>(std::min(static_cast<typeof(toread)>(sizeof(buf)), toread));
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auto l = read(haystack_fd.get(), buf, wlen);
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if (l < 1) {
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PLOG(ERROR) << "Failed read";
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if (errno != EINTR) {
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return false;
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}
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}
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area.append(buf, l);
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toread -= l;
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}
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}
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LOG(DEBUG) << "Searching " << area.size() << " bytes of " << needle;
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LOG(DEBUG) << "First position of blob: " << area.find(randomhex);
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return true;
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}
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int CheckEncryption(const std::string& path) {
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auto deNeedle(path);
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deNeedle += "/misc";
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if (android::vold::PrepareDir(deNeedle, 01771, AID_SYSTEM, AID_MISC)) {
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return -1;
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}
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deNeedle += "/vold";
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if (android::vold::PrepareDir(deNeedle, 0700, AID_ROOT, AID_ROOT)) {
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return -1;
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}
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deNeedle += "/checkEncryption";
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auto neNeedle(path);
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neNeedle += "/unencrypted/checkEncryption";
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check_file(deNeedle);
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check_file(neNeedle);
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return 0;
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}
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} // namespace vold
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} // namespace android
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