main_apphead_string()

[Seth Arnold]

Hello, I gave xdelta3 a very quick look as part of the Ubuntu main inclusion process:
https://bugs.launchpad.net/ubuntu/+source/xdelta3/+bug/1647222

Can main_apphead_string() be tricked by an x input that ends with a / char?

static const char*
main_apphead_string (const char* x)
{
  const char *y;   

  if (x == NULL) { return ""; }

  if (strcmp (x, "/dev/stdin") == 0 ||
      strcmp (x, "/dev/stdout") == 0 ||
      strcmp (x, "/dev/stderr") == 0) { return "-"; }
  
  // TODO: this is not portable
  return (y = strrchr (x, '/')) == NULL ? x : y + 1;
}   

If the input ends with / then the return value will point the NUL at the end. Are the callers prepared to handle this case? Or is this input forbidden elsewhere?

Thanks