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jmacd / xdelta

open-source binary diff, delta/differential compression tools, VCDIFF/RFC 3284 delta compression
http://xdelta.org
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main_apphead_string() #233

Open setharnold opened 7 years ago

setharnold commented 7 years ago

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