[FFmpeg-devel] [PATCH 02/11] avcodec/proresdec: Consider negative bits left

From: Michael Niedermayer <michael@niedermayer.cc>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: [FFmpeg-devel] [PATCH 02/11] avcodec/proresdec: Consider negative bits left
Date: Sat, 20 Jul 2024 02:52:32 +0200
Message-ID: <20240720005241.726089-2-michael@niedermayer.cc> (raw)
In-Reply-To: <20240720005241.726089-1-michael@niedermayer.cc>

Fixes: 70036/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PRORES_fuzzer-6298797647396864
Fixes: shift exponent 40 is too large for 32-bit type 'uint32_t' (aka 'unsigned int')

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/proresdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/proresdec.c b/libavcodec/proresdec.c
index ec1d0bd0be9..6a256107b49 100644
--- a/libavcodec/proresdec.c
+++ b/libavcodec/proresdec.c
@@ -511,7 +511,7 @@ static av_always_inline int decode_ac_coeffs(AVCodecContext *avctx, GetBitContex
 
     for (pos = block_mask;;) {
         bits_left = gb->size_in_bits - re_index;
-        if (!bits_left || (bits_left < 32 && !SHOW_UBITS(re, gb, bits_left)))
+        if (bits_left <= 0 || (bits_left < 32 && !SHOW_UBITS(re, gb, bits_left)))
             break;
 
         DECODE_CODEWORD(run, run_to_cb[FFMIN(run,  15)], LAST_SKIP_BITS);
-- 
2.45.2

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