You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
93 lines
2.2 KiB
93 lines
2.2 KiB
/**
|
|
* Copyright (C) 2018 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.
|
|
*/
|
|
#define _GNU_SOURCE
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stdlib.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/ptrace.h>
|
|
#include <sys/stat.h>
|
|
#include <unistd.h>
|
|
#include <../includes/common.h>
|
|
|
|
volatile char *mem = 0;
|
|
|
|
// child
|
|
int check_zero_page() {
|
|
char *temp =
|
|
(char *)mmap(0, 4096, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
|
|
int zeropage = *(int *)temp;
|
|
munmap(temp, 4096);
|
|
return zeropage;
|
|
}
|
|
|
|
// child
|
|
int do_child(int val) {
|
|
// enable tracing and wait until parent is finished unlocking zero page
|
|
ptrace(PTRACE_TRACEME, 0, 0, 0);
|
|
sleep(2);
|
|
|
|
mprotect((void *)mem, 4096, PROT_READ | PROT_WRITE);
|
|
|
|
// try to corrupt zero page
|
|
mem[0] = val;
|
|
|
|
int zeropage = check_zero_page();
|
|
return zeropage ? EXIT_VULNERABLE : 0;
|
|
}
|
|
|
|
// parent
|
|
int do_trace(pid_t child) {
|
|
int status = 0;
|
|
sleep(1); // wait until child is set up
|
|
kill(child, SIGSTOP); // pause child
|
|
waitpid(child, &status, 0);
|
|
|
|
// unlock zero page
|
|
status = ptrace(PTRACE_PEEKDATA, child, mem, 0);
|
|
|
|
// stop tracing so child can continue
|
|
ptrace(PTRACE_DETACH, child, 0, 0);
|
|
kill(child, SIGCONT);
|
|
return status;
|
|
}
|
|
|
|
int main(void) {
|
|
|
|
char value = 0xAA;
|
|
|
|
mem = (volatile char *)mmap(0, 4096, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
|
|
mprotect((void *)mem, 4096, PROT_NONE);
|
|
|
|
pid_t child = fork();
|
|
|
|
if (child == 0) {
|
|
return do_child(value);
|
|
} else {
|
|
do_trace(child);
|
|
}
|
|
|
|
int status = 0;
|
|
waitpid(child, &status, 0); // wait for child to exit naturally
|
|
int exit = WEXITSTATUS(status); // get child exit status
|
|
|
|
munmap((void *)mem, 4096);
|
|
|
|
return exit;
|
|
}
|