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

[Jiangli Zhou]

> On May 6, 2016, at 4:14 AM, Ioi Lam <ioi.lam at oracle.com> wrote:
> 
> 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’;

Good catch. Allocating with an extra byte is a safer solution here.

Thanks,
Jiangli

> 
> 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
>