maria-developers team mailing list archive

[Alexander Barkov <bar@xxxxxxxxxxx>]

Hi Sergei,

On 02/09/2016 05:01 PM, Sergei Golubchik wrote:
> Hi, Alexander!
>
> On Feb 09, Alexander Barkov wrote:
> > Hello Sergei,
> >
> > Please review a fix for MDEV-9371.
> >
> > I'd suggest to push it to 10.0 instead of 5.5,
> > as MySQL fixed this bug in 5.6 (not 5.5).
>
> I think 5.5 is fine. It's clearly a bug. And a very safe fix.
>
> > Also, I think it's worthy to backport MDEV-9332 to 10.0 as well,
> > because the patch for MDEV-9371 touches the test which
> > we modified in MDEV-9332.
>
> Dunno. Is 5.5 affected? Or only 10.0 is affected?

Both 5.5 and 10.0 are affected.

But on the other hand, backporting low level String related fixes
(like in MDEV-9332) is somewhat dangerous. Strings (like datetime)
are fragile.

Ok, never mind. Let's just have everything as planned.

I added the commend that you suggested below and pushed to 5.5.

Thanks.


> > diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
> > index aca66fc..ca0cc47 100644
> > --- a/sql/item_strfunc.cc
> > +++ b/sql/item_strfunc.cc
> > @@ -1212,7 +1212,7 @@ String *Item_func_insert::val_str(String *str)
> >      length= res->charpos((int) length, (uint32) start);
> >
> >     /* Re-testing with corrected params */
> > -  if (start > res->length())
> > +  if (start + 1 > res->length())
>
> that's fine, of course. But please, add a comment, like
>
>                                      // remember, start = args[1].val_int() - 1
>
> or something else, whatever you want, to remind about -1.
>
> >       return res; /* purecov: inspected */        // Wrong param; skip insert
> >     if (length > res->length() - start)
> >       length= res->length() - start;
>
> Regards,
> Sergei
> Chief Architect MariaDB
> and security@xxxxxxxxxxx