From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH] avcodec/get_bits: don't shift more bits than available in an unsigned with get_leb()
Date: Tue, 30 Jan 2024 23:19:30 +0100
Message-ID: <AS8P250MB074408C79280FCE3C7D44E3C8F7D2@AS8P250MB0744.EURP250.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20240130221612.970-1-jamrial@gmail.com>
James Almer:
> Signed-off-by: James Almer <jamrial@gmail.com>
> ---
> libavcodec/get_bits.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
> index 9e19d2a439..c0cc7c0a7d 100644
> --- a/libavcodec/get_bits.h
> +++ b/libavcodec/get_bits.h
> @@ -725,7 +725,7 @@ static inline unsigned get_leb(GetBitContext *s) {
> int byte = get_bits(s, 8);
> unsigned bits = byte & 0x7f;
> more = byte & 0x80;
> - if (i <= 4)
> + if (i <= 3 || (i == 4 && bits < (1 << 4)))
> leb |= bits << (i * 7);
> if (++i == 8)
> break;
This truncates more bits than necessary, which is IMO against the
documentation of this function.
- Andreas
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next prev parent reply other threads:[~2024-01-30 22:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 22:16 James Almer
2024-01-30 22:19 ` Andreas Rheinhardt [this message]
2024-01-30 22:34 ` James Almer
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