[FFmpeg-devel] [PATCH] check for invalid sym values in indeo decoder (issue 2523)

[Daniel Kang]

On Fri, Jan 14, 2011 at 8:42 PM, Michael Niedermayer <michaelni at gmx.at>wrote:

>  On Tue, Jan 11, 2011 at 05:00:55PM -0500, Daniel Kang wrote:
> > On Tue, Jan 11, 2011 at 4:21 PM, Kostya <kostya.shishkov at gmail.com>
> wrote:
> >
> > > On Tue, Jan 11, 2011 at 03:26:19PM -0500, Daniel Kang wrote:
> > > > On Tue, Jan 11, 2011 at 11:24 AM, Michael Niedermayer <
> michaelni at gmx.at
> > > >wrote:
> > > >
> > > [...]
> > > > >
> > > > > this is a error condition and continuing with undefined values
> makes no
> > > > > sense
> > > > > also i suspect only one of teh 2 checks is needed
> > > >
> > > >
> > > > I have updated the message and return an error. The invalid sym in
> this
> > > > case are -1. I am not sure if the other check is needed, as the
> sample
> > > > file does not encounter values greater than 256.
> > >
> > > else{} is not needed there, just move assignment under the check
> >
> >
> > Patch updated without the else.
>
> >  ivi_common.c |    4 ++++
> >  1 file changed, 4 insertions(+)
> > 74f624d397ede46b559b689765719acfd7bba1e5  indeo_invalid_sym_check.diff
> > From 9d36b5fc04f984f30dce1c4fd4f3f513f4d59c32 Mon Sep 17 00:00:00 2001
> > From: Daniel Kang <daniel.d.kang at gmail.com>
> > Date: Sun, 9 Jan 2011 18:50:28 -0500
> > Subject: [PATCH] Check for invalid indeo sym value
> >
> > ---
> >  libavcodec/ivi_common.c |    4 ++++
> >  1 files changed, 4 insertions(+), 0 deletions(-)
> >
> > diff --git a/libavcodec/ivi_common.c b/libavcodec/ivi_common.c
> > index b158458..0788959 100644
> > --- a/libavcodec/ivi_common.c
> > +++ b/libavcodec/ivi_common.c
> > @@ -404,6 +404,10 @@ int ff_ivi_decode_blocks(GetBitContext *gb,
> IVIBandDesc *band, IVITile *tile)
> >                          hi  = get_vlc2(gb, band->blk_vlc.tab->table,
> IVI_VLC_BITS, 1);
> >                          val = IVI_TOSIGNED((hi << 6) | lo); /* merge
> them and convert into signed val */
> >                      } else {
> > +                        if (sym < 0 || sym >= 256) {
>
> this can be simplifed to
> if(sym >= 256U)
>
> because 256U is unsigned and that makes the comparission unsigned and
> negative
> values are when looked at unsigned large
>
> otherwise ok from my side as well


Patch updated with only one check.
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