[FFmpeg-cvslog] avcodec/imc: Clear padding of buf16

[Michael Niedermayer]

ffmpeg | branch: release/6.1 | Michael Niedermayer <michael at niedermayer.cc> | Sun Aug  3 14:39:53 2025 +0200| [6f8a9bea331c8d9be5bee54c1f2df9afda0da0fb] | committer: Michael Niedermayer

avcodec/imc: Clear padding of buf16

Fixes: use of uninitialized memory
Fixes: 423673969/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IAC_fuzzer-6685890556788736

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 715df4b1ff398758ca1b8a82c3d16940bc63fc56)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6f8a9bea331c8d9be5bee54c1f2df9afda0da0fb
---

 libavcodec/imc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/imc.c b/libavcodec/imc.c
index 754ceff958..eb6709a876 100644
--- a/libavcodec/imc.c
+++ b/libavcodec/imc.c
@@ -971,6 +971,8 @@ static int imc_decode_frame(AVCodecContext *avctx, AVFrame *frame,
 
     LOCAL_ALIGNED_16(uint16_t, buf16, [(IMC_BLOCK_SIZE + AV_INPUT_BUFFER_PADDING_SIZE) / 2]);
 
+    memset(buf16 + IMC_BLOCK_SIZE/2, 0, AV_INPUT_BUFFER_PADDING_SIZE);
+
     q->avctx = avctx;
 
     if (buf_size < IMC_BLOCK_SIZE * avctx->ch_layout.nb_channels) {