From: "Dai, Jianhui J" <jianhui.j.dai-at-intel.com@ffmpeg.org>
To: "ffmpeg-devel@ffmpeg.org" <ffmpeg-devel@ffmpeg.org>
Subject: [FFmpeg-devel] [PATCH v1] avcodec/cbs_vp8: Improve the bitstream position check
Date: Thu, 25 Jan 2024 00:54:27 +0000
Message-ID: <DS7PR11MB7949CF2C01F31B4B8597EC61B17A2@DS7PR11MB7949.namprd11.prod.outlook.com> (raw)
The VP8 compressed header may not be byte-aligned due to boolean
coding. Use bitwise comparison to prevent the potential overread.
Signed-off-by: Jianhui Dai <jianhui.j.dai@intel.com>
---
libavcodec/cbs_vp8.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/libavcodec/cbs_vp8.c b/libavcodec/cbs_vp8.c
index 065156c248..13acad3724 100644
--- a/libavcodec/cbs_vp8.c
+++ b/libavcodec/cbs_vp8.c
@@ -327,9 +327,10 @@ static int cbs_vp8_read_unit(CodedBitstreamContext *ctx,
if (err < 0)
return err;
+ // Position may not be byte-aligned after compressed header; using bits
+ // count comparison for accuracy.
pos = get_bits_count(&gbc);
- pos /= 8;
- av_assert0(pos <= unit->data_size);
+ av_assert0(pos <= unit->data_size * 8);
frame->data_ref = av_buffer_ref(unit->data_ref);
if (!frame->data_ref)
--
2.25.1
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next reply other threads:[~2024-01-25 0:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-25 0:54 Dai, Jianhui J [this message]
2024-02-23 0:43 ` Dai, Jianhui J
2024-03-05 5:33 ` Dai, Jianhui J
2024-03-18 11:34 ` Andreas Rheinhardt
2024-03-19 6:39 ` Dai, Jianhui J
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