问不理解这种行为:更改指针所指向的值会导致指针值本身在C中更改？

EN

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

int main(int argc, char *argv[])
{
  srand(time(NULL));
  int secret = rand();
  char buf[8];
  char *aft_buf = buf + 8;
  printf("aft buf address = %p\n", aft_buf);
  int *canary = (int *) aft_buf;
  *canary = secret;
  printf("canary address = %p\n", canary); // this value becomes different from aft_buf. why?
  
  return 0;
}