Re: [xml] "double"s and schema validation

[Daniel Veillard <veillard redhat com>]

On Thu, Jul 22, 2010 at 02:38:16PM +0200, Csaba Raduly wrote:
> On Wed, Jul 21, 2010 at 6:19 PM, Andrew W. Nosenko  wrote:
> > On Wed, Jul 21, 2010 at 14:23, Csaba Raduly wrote:
> > > On Tue, Jul 20, 2010 at 3:40 AM, Dan Sommers  wrote:
> ...
> > > > I tracked it down to xmlschematypes.c, starting around line 2465, where
> > > > it starts scanning the input for something suitable for sscanf("%lf").
> > > > Should that code contain an extra check that there is at least one digit
> > > > somewhere?
> > >
> > > I think you are right. This code:
> > >                while ((*cur >= '0') && (*cur <= '9')) {
> > >                    cur++;
> > >                }
> > > accepts 0 or more digits (before the period); perhaps it should check
> > > for 1 or more digits instead:
> >
> > No!  The case like ".5" instead of "0.5" is perfectly valid and widely used!
> > Whether the "." or "e" are valid string representation of the "double"
> > type or should be rejected -- it's another matter.  But zero digits
> > before dot are absolutely correct and should be allowed.
>
> Just because it's widely used it doesn't mean that it is "absolutely correct" :)
> (Also, the rules for what's a valid float in C may not be the same for XSD)
>
> Anyway, here's a revised version:
> --- xmlschemastypes2.c  2010-07-21 13:17:12.229467800 +0200
> +++ xmlschemastypes.c   2010-07-22 14:00:05.965759600 +0200
> @@ -2392,6 +2392,8 @@
>          case XML_SCHEMAS_DOUBLE:{
>                  const xmlChar *cur = value;
>                  int neg = 0;
> +                int digits_before = 0;
> +                int digits_after  = 0;
>
>          if (normOnTheFly)
>              while IS_WSP_BLANK_CH(*cur) cur++;
> @@ -2463,13 +2465,16 @@
>                  if ((cur[0] == 0) || (cur[0] == '+') || (cur[0] == '-'))
>                      goto return1;
>                  while ((*cur >= '0') && (*cur <= '9')) {
> -                    cur++;
> +                    digits_before++; cur++;
>                  }
>                  if (*cur == '.') {
>                      cur++;
> -                    while ((*cur >= '0') && (*cur <= '9'))
> -                        cur++;
> +                    while ((*cur >= '0') && (*cur <= '9')) {
> +                        digits_after++; cur++;
> +                    }
>                  }
> +                if (digits_before + digits_after == 0)
> +                    goto return1;
>                  if ((*cur == 'e') || (*cur == 'E')) {
>                      cur++;
>                      if ((*cur == '-') || (*cur == '+'))

  Okay that patch looks fine, except for mail mangling and code format,
so I applied it manually, look fine, passes regtests, so pushed to git,

 thanks !

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/