[FFmpeg-devel] [PATCH] libavformat/amr.c: Check return value from avio_read()

[John Rummell]

Updated to return AVERROR_INVALIDDATA.

On Wed, Apr 1, 2020 at 12:33 PM Michael Niedermayer <michael at niedermayer.cc>
wrote:

> On Mon, Mar 30, 2020 at 09:48:13PM -0700, John Rummell wrote:
> > Hit send too soon. Patch attached.
> >
> > On Mon, Mar 30, 2020 at 9:44 PM John Rummell <jrummell at chromium.org>
> wrote:
> >
> > > Another uninitialized memory access detected by the Chromium fuzzers.
> > >
>
> >  amr.c |    6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > db486a31c1d3c7f4f51a7e5f5333f871744d6c87
> 0001-libavformat-amr.c-Check-return-value-from-avio_read.patch
> > From 0ef90d64a760f730652f3832da2abca47cff62d6 Mon Sep 17 00:00:00 2001
> > From: John Rummell <jrummell at chromium.org>
> > Date: Mon, 30 Mar 2020 21:30:33 -0700
> > Subject: [PATCH] libavformat/amr.c: Check return value from avio_read()
> >
> > If the buffer doesn't contain enough bytes when reading a stream,
> > fail rather than continuing on with initialized data. Caught by
> > Chromium fuzzeras (crbug.com/1065731).
> > ---
> >  libavformat/amr.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/libavformat/amr.c b/libavformat/amr.c
> > index eccbbde5b0..8570d43302 100644
> > --- a/libavformat/amr.c
> > +++ b/libavformat/amr.c
> > @@ -89,13 +89,15 @@ static int amr_read_header(AVFormatContext *s)
> >      AVStream *st;
> >      uint8_t header[9];
> >
> > -    avio_read(pb, header, 6);
> > +    if (avio_read(pb, header, 6) != 6)
> > +        return -1;
> >
> >      st = avformat_new_stream(s, NULL);
> >      if (!st)
> >          return AVERROR(ENOMEM);
> >      if (memcmp(header, AMR_header, 6)) {
> > -        avio_read(pb, header + 6, 3);
> > +        if (avio_read(pb, header + 6, 3) != 3)
> > +            return -1;
>
> I see some of the existing code uses -1 instead of AVERROR*
> but i think for newly added cases AVERROR* codes would be better
>
> thx
>
> [...]
>
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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