Re: [PATCH] Fix out-of-bouds access (src/common/wchar.c)

On Thu, Feb 17, 2022 at 05:24:58PM +0900, Kyotaro Horiguchi wrote:
> At Thu, 17 Feb 2022 15:50:09 +0800, Julien Rouhaud <rjuju123@gmail.com> wrote in 
> > On Thu, Feb 17, 2022 at 03:51:26PM +0900, Kyotaro Horiguchi wrote:
> > > So, the function doesn't return 63 for all registered names and wrong
> > > names.
> > > 
> > > So other possibilities I can think of are..
> > > - Someone had broken pg_encname_tbl[]
> > > - Cosmic ray hit, or ill memory cell.
> > > - Coverity worked wrong way.
> > > 
> > > Could you show the workload for the Coverity warning here?
> > 
> > The 63 upthread was hypothetical right?  pg_encoding_max_length() shouldn't be
> 
> I understand that Coverity complaind pg_verify_mbstr_len is fed with
> encoding = 63 by length_in_encoding.  I don't know what made Coverity
> think so.

Not sure either.  As you said this assumes that pg_char_to_encoding() can
return something higher than _PG_LAST_ENCODING_ and I also fail to see how that
could happen.