From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH 2/5] avcodec/cdgraphics: avoid signed overflow in alpha
Date: Thu, 23 Dec 2021 22:45:47 +0100
Message-ID: <AM7PR03MB666041E6DCC025511CCBB3F88F7E9@AM7PR03MB6660.eurprd03.prod.outlook.com> (raw)
In-Reply-To: <20211223211527.20408-2-michael@niedermayer.cc>
Michael Niedermayer:
> Fixes: left shift of 255 by 24 places cannot be represented in type 'int'
> Fixes: 42766/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CDGRAPHICS_fuzzer-5142826105569280
>
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
> libavcodec/cdgraphics.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/cdgraphics.c b/libavcodec/cdgraphics.c
> index 06f83920943..f54ce5a05c0 100644
> --- a/libavcodec/cdgraphics.c
> +++ b/libavcodec/cdgraphics.c
> @@ -122,7 +122,7 @@ static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
> r = ((color >> 8) & 0x000F) * 17;
> g = ((color >> 4) & 0x000F) * 17;
> b = ((color ) & 0x000F) * 17;
> - palette[i + array_offset] = cc->alpha[i + array_offset] << 24 | r << 16 | g << 8 | b;
> + palette[i + array_offset] = (unsigned)cc->alpha[i + array_offset] << 24 | r << 16 | g << 8 | b;
> }
> cc->frame->palette_has_changed = 1;
> }
>
LGTM. Although I'd prefer uint32_t here, as this is exactly what is
needed and it fits the type of palette.
- Andreas
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next prev parent reply other threads:[~2021-12-23 21:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-23 21:15 [FFmpeg-devel] [PATCH 1/5] avcodec/targa: Check input size for uncompressed TGA before allocation Michael Niedermayer
2021-12-23 21:15 ` [FFmpeg-devel] [PATCH 2/5] avcodec/cdgraphics: avoid signed overflow in alpha Michael Niedermayer
2021-12-23 21:45 ` Andreas Rheinhardt [this message]
2021-12-25 10:43 ` Michael Niedermayer
2021-12-23 21:15 ` [FFmpeg-devel] [PATCH 3/5] avformat/flvdec: timestamps cannot use the full int64 range Michael Niedermayer
2021-12-30 20:44 ` Michael Niedermayer
2021-12-23 21:15 ` [FFmpeg-devel] [PATCH 4/5] avcodec/apedec: fix integer overflow in 8bit samples Michael Niedermayer
2021-12-30 20:42 ` Michael Niedermayer
2021-12-23 21:15 ` [FFmpeg-devel] [PATCH 5/5] avformat/mvdec: Check bytes_per_sample Michael Niedermayer
2021-12-23 23:07 ` Peter Ross
2021-12-24 3:32 ` John-Paul Stewart
2021-12-24 16:58 ` Michael Niedermayer
2021-12-24 20:29 ` John-Paul Stewart
2021-12-25 10:43 ` Michael Niedermayer
2021-12-30 21:11 ` [FFmpeg-devel] [PATCH 1/5] avcodec/targa: Check input size for uncompressed TGA before allocation Michael Niedermayer
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