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

[Michael Niedermayer]

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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