avcodec/hevcdec: Check luma/chroma_log2_weight_denom

Fixes: signed integer overflow: 3 + 2147483647 cannot be represented in type 'int'
Fixes: 5888/clusterfuzz-testcase-minimized-5634701067812864

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/hevcdec.c

@@ -151,12 +151,18 @@ static int pred_weight_table(HEVCContext *s, GetBitContext *gb)
     int luma_log2_weight_denom;
 
     luma_log2_weight_denom = get_ue_golomb_long(gb);
-    if (luma_log2_weight_denom < 0 || luma_log2_weight_denom > 7)
+    if (luma_log2_weight_denom < 0 || luma_log2_weight_denom > 7) {
         av_log(s->avctx, AV_LOG_ERROR, "luma_log2_weight_denom %d is invalid\n", luma_log2_weight_denom);
+        return AVERROR_INVALIDDATA;
+    }
     s->sh.luma_log2_weight_denom = av_clip_uintp2(luma_log2_weight_denom, 3);
     if (s->ps.sps->chroma_format_idc != 0) {
-        int delta = get_se_golomb(gb);
-        s->sh.chroma_log2_weight_denom = av_clip_uintp2(s->sh.luma_log2_weight_denom + delta, 3);
+        int64_t chroma_log2_weight_denom = luma_log2_weight_denom + (int64_t)get_se_golomb(gb);
+        if (chroma_log2_weight_denom < 0 || chroma_log2_weight_denom > 7) {
+            av_log(s->avctx, AV_LOG_ERROR, "chroma_log2_weight_denom %"PRId64" is invalid\n", chroma_log2_weight_denom);
+            return AVERROR_INVALIDDATA;
+        }
+        s->sh.chroma_log2_weight_denom = chroma_log2_weight_denom;
     }
 
     for (i = 0; i < s->sh.nb_refs[L0]; i++) {