110 lines
3.2 KiB
C++
Executable File
110 lines
3.2 KiB
C++
Executable File
/*
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* Copyright (C) 2022 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 "androidfw/ApkParsing.h"
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#include <algorithm>
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#include <array>
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#include <stdlib.h>
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#include <string_view>
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#include <sys/types.h>
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const std::string_view APK_LIB = "lib/";
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const size_t APK_LIB_LEN = APK_LIB.size();
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const std::string_view LIB_PREFIX = "/lib";
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const size_t LIB_PREFIX_LEN = LIB_PREFIX.size();
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const std::string_view LIB_SUFFIX = ".so";
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const size_t LIB_SUFFIX_LEN = LIB_SUFFIX.size();
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static const std::array<std::string_view, 2> abis = {"arm64-v8a", "x86_64"};
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namespace android::util {
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const char* ValidLibraryPathLastSlash(const char* fileName, bool suppress64Bit, bool debuggable) {
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// Make sure the filename is at least to the minimum library name size.
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const size_t fileNameLen = strlen(fileName);
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static const size_t minLength = APK_LIB_LEN + 2 + LIB_PREFIX_LEN + 1 + LIB_SUFFIX_LEN;
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if (fileNameLen < minLength) {
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return nullptr;
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}
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const char* lastSlash = strrchr(fileName, '/');
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if (!lastSlash) {
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return nullptr;
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}
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// Skip directories.
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if (*(lastSlash + 1) == 0) {
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return nullptr;
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}
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// Make sure the filename is safe.
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if (!isFilenameSafe(lastSlash + 1)) {
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return nullptr;
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}
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// Make sure there aren't subdirectories by checking if the next / after lib/ is the last slash
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if (memchr(fileName + APK_LIB_LEN, '/', fileNameLen - APK_LIB_LEN) != lastSlash) {
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return nullptr;
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}
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if (!debuggable) {
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// Make sure the filename starts with lib and ends with ".so".
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if (strncmp(fileName + fileNameLen - LIB_SUFFIX_LEN, LIB_SUFFIX.data(), LIB_SUFFIX_LEN) != 0
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|| strncmp(lastSlash, LIB_PREFIX.data(), LIB_PREFIX_LEN) != 0) {
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return nullptr;
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}
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}
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// Don't include 64 bit versions if they are suppressed
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if (suppress64Bit && std::find(abis.begin(), abis.end(), std::string_view(
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fileName + APK_LIB_LEN, lastSlash - fileName - APK_LIB_LEN)) != abis.end()) {
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return nullptr;
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}
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return lastSlash;
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}
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bool isFilenameSafe(const char* filename) {
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off_t offset = 0;
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for (;;) {
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switch (*(filename + offset)) {
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case 0:
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// Null.
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// If we've reached the end, all the other characters are good.
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return true;
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case 'A' ... 'Z':
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case 'a' ... 'z':
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case '0' ... '9':
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case '+':
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case ',':
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case '-':
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case '.':
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case '/':
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case '=':
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case '_':
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offset++;
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break;
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default:
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// We found something that is not good.
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return false;
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}
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}
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// Should not reach here.
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}
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} |