avcodec/hevcdec: Check slice_cb_qp_offset / slice_cr_qp_offset

Fixes: signed integer overflow: 29 + 2147483640 cannot be represented in type 'int'
Fixes: 25413/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5697909331591168

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

@@ -815,6 +815,11 @@ static int hls_slice_header(HEVCContext *s)
         if (s->ps.pps->pic_slice_level_chroma_qp_offsets_present_flag) {
             sh->slice_cb_qp_offset = get_se_golomb(gb);
             sh->slice_cr_qp_offset = get_se_golomb(gb);
+            if (sh->slice_cb_qp_offset < -12 || sh->slice_cb_qp_offset > 12 ||
+                sh->slice_cr_qp_offset < -12 || sh->slice_cr_qp_offset > 12) {
+                av_log(s->avctx, AV_LOG_ERROR, "Invalid slice cx qp offset.\n");
+                return AVERROR_INVALIDDATA;
+            }
         } else {
             sh->slice_cb_qp_offset = 0;
             sh->slice_cr_qp_offset = 0;