[Ffmpeg-devel] [PATCH] fix jpegls unitialized data reading
Sun Dec 10 02:28:37 CET 2006
On Sat, Dec 09, 2006 at 11:52:54PM +0100, Reimar D?ffinger wrote:
> On Sat, Dec 09, 2006 at 11:48:17PM +0100, Reimar D?ffinger wrote:
> > On Sat, Dec 09, 2006 at 11:29:57PM +0100, Reimar D?ffinger wrote:
> > > + put_bits(&pb2, 16, 0);
> > > flush_put_bits(&pb2);
> > > /* do escape coding */
> > > - size = put_bits_count(&pb2) >> 3;
> > > + size = (put_bits_count(&pb2) >> 3) - 2;
> > Just initializing 8 extra bits instead of 16 is enough, because v ==
> > 0xff is not possible when we already hit the end before reading v
> > completely.
> > Actually that even means that 7 bits extra initialization would be
> > enough, but that would be complicate to compensate due to
> > flush_put_bits.
> > Of course, just a memset of buf2 to 0 right at the start works, too.
> Sorry, yet another correction. init_get_bits should get the larger size,
> too, in case somebody adds thorough checking of get_bits limits e.g. for
> debugging purposes.
hmm what about align_put_bits() ?
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
More information about the ffmpeg-devel