RFR(xs): 8155574: ClassLoader::initialize_module_loader_map crashes if the char_buf is not NULL terminated

[Ioi Lam]

Hi Calvin,

     char* char_buf = (char*)buffer;
-   int buflen = (int)strlen(char_buf);
     char* begin_ptr = char_buf;
     char* end_ptr = strchr(begin_ptr, '\n');

The strchr() function also expects the buffer to be NUL terminated. So 
you might have problem later

  985     end_ptr = strchr(begin_ptr, '\n');   <<<<< HERE
  986   }

It will be must safer if you allocate an extra byte, and explicitly set 
it to zero:

  char* buffer = NEW_RESOURCE_ARRAY(char, size+1);
  buffer[size] = '\0';

Thanks
- Ioi



On 5/5/16 11:20 AM, Calvin Cheung wrote:
>
> Please review this small change for fixing char_buf may not be NULL 
> terminated.
> Instead of finding the length of char_buf by using strlen(), this fix 
> uses the size returned from JImageFindResource().
>
> bug: https://bugs.openjdk.java.net/browse/JDK-8155574
> webrev: http://cr.openjdk.java.net/~ccheung/8155574/webrev.00/
>
> Testing:
>     JPRT
>     RBT on hotspot_runtime
>
> thanks,
> Calvin