[FFmpeg-devel] [PATCH] lavf/mov.c: Avoid heap allocation wraps and OOB in mov_read_{senc, saiz, udta_string}()

[Matthew Wolenetz]

I've separated and updated the mov_read_udta_string() patch, attached.
It prevents accessing MOVContext.meta_keys[0] in that method. That array is
1-based.

On Wed, Dec 14, 2016 at 5:40 PM, Andreas Cadhalpun <
andreas.cadhalpun at googlemail.com> wrote:

> On 15.12.2016 00:37, Matthew Wolenetz wrote:
> > From 8622f9398e7c89a664c4c2ceff9d35b89ff17bb5 Mon Sep 17 00:00:00 2001
> > From: Matt Wolenetz <wolenetz at chromium.org>
> > Date: Tue, 6 Dec 2016 12:54:23 -0800
> > Subject: [PATCH] lavf/mov.c: Avoid heap allocation wraps and OOB in
> >  mov_read_{senc,saiz,udta_string}()
> >
> > Core of patch is from paul at paulmehta.com
> > Reference https://crbug.com/643952
> > ---
> >  libavformat/mov.c | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/libavformat/mov.c b/libavformat/mov.c
> > index e506d20..87ad91a 100644
> > --- a/libavformat/mov.c
> > +++ b/libavformat/mov.c
> > @@ -404,7 +404,7 @@ retry:
> >                  return ret;
> >              } else if (!key && c->found_hdlr_mdta && c->meta_keys) {
> >                  uint32_t index = AV_RB32(&atom.type);
> > -                if (index < c->meta_keys_count) {
> > +                if (index < c->meta_keys_count && index > 0) {
>
> This should be in a separate patch.
>
> >                      key = c->meta_keys[index];
> >                  } else {
> >                      av_log(c->fc, AV_LOG_WARNING,
> > @@ -4502,8 +4502,8 @@ static int mov_read_senc(MOVContext *c,
> AVIOContext *pb, MOVAtom atom)
> >
> >      avio_rb32(pb);        /* entries */
> >
> > -    if (atom.size < 8) {
> > -        av_log(c->fc, AV_LOG_ERROR, "senc atom size %"PRId64" too
> small\n", atom.size);
> > +    if (atom.size < 8 || atom.size > UINT_MAX) {
> > +        av_log(c->fc, AV_LOG_ERROR, "senc atom size %"PRId64"
> invalid\n", atom.size);
> >          return AVERROR_INVALIDDATA;
> >      }
> >
> > @@ -4571,6 +4571,11 @@ static int mov_read_saiz(MOVContext *c,
> AVIOContext *pb, MOVAtom atom)
> >          return 0;
> >      }
> >
> > +    if (atom.size > UINT_MAX) {
> > +        av_log(c->fc, AV_LOG_ERROR, "saiz atom auxiliary_info_sizes
> size %"PRId64" invalid\n", atom.size);
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> >      /* save the auxiliary info sizes as is */
> >      data_size = atom.size - atom_header_size;
> >
>
> And these should also check for SIZE_MAX.
>
> Best regards,
> Andreas
> _______________________________________________
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> ffmpeg-devel at ffmpeg.org
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>
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