From a5d4e7e3f981ce90b92a9da7da26a3c2a2e061e9 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Mon, 20 Feb 2023 20:04:18 +0100
Subject: [PATCH] avcodec/rka: avoid negative value shift

Fixes: left shift of negative value -81
Fixes: 56061/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_RKA_fuzzer-4649758062149632

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

diff --git a/libavcodec/rka.c b/libavcodec/rka.c
index 7452acf27f..1eb2289e58 100644
--- a/libavcodec/rka.c
+++ b/libavcodec/rka.c
@@ -737,7 +737,7 @@ static int decode_filter(RKAContext *s, ChContext *ctx, ACoder *ac, int off, uns
                 }
                 ctx->buf0[off] = ctx->buf1[off] + ctx->buf0[off + -1];
             } else {
-                val <<= ctx->cmode;
+                val *= 1 << ctx->cmode;
                 sum += ctx->buf0[off + -1] + val;
                 switch (s->bps) {
                 case 16: sum = av_clip_int16(sum); break;