Fix memory leak in __printf_fp_l (bug 26215)

[Joseph Myers]

On Fri, 10 Jul 2020, Florian Weimer via Libc-alpha wrote:

> * Joseph Myers:
> 
> > __printf_fp_l has a memory leak in the case of some I/O errors, where
> > both buffer and wbuffer have been malloced but the handling of I/O
> > errors only frees wbuffer.  This patch fixes this by moving the
> > declaration of buffer to an outer scope and ensuring that it is freed
> > when wbuffer is freed.
> 
> Do we need to treat this as a securityh vulnerability?  I don't think
> so, because there are no impacted applications as far as I can tell.

I don't know whether any of bugs 26201, 26211, 26214, 26215 (all memory 
issues in printf with valid but unusual format strings) should be 
considered as security issues.

-- 
Joseph S. Myers
joseph@codesourcery.com