avcodec/h264: Check weight values to be within the specs limits.

Fixes: integer overflows
Fixes: 911/clusterfuzz-testcase-5415105606975488

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpegReviewed-by: "Ronald S. Bultje" <rsbultje@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/h264_parse.c

@@ -59,6 +59,9 @@ int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
             if (luma_weight_flag) {
                 pwt->luma_weight[i][list][0] = get_se_golomb(gb);
                 pwt->luma_weight[i][list][1] = get_se_golomb(gb);
+                if ((int8_t)pwt->luma_weight[i][list][0] != pwt->luma_weight[i][list][0] ||
+                    (int8_t)pwt->luma_weight[i][list][1] != pwt->luma_weight[i][list][1])
+                    goto out_range_weight;
                 if (pwt->luma_weight[i][list][0] != luma_def ||
                     pwt->luma_weight[i][list][1] != 0) {
                     pwt->use_weight             = 1;
@@ -76,6 +79,9 @@ int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
                     for (j = 0; j < 2; j++) {
                         pwt->chroma_weight[i][list][j][0] = get_se_golomb(gb);
                         pwt->chroma_weight[i][list][j][1] = get_se_golomb(gb);
+                        if ((int8_t)pwt->chroma_weight[i][list][j][0] != pwt->chroma_weight[i][list][j][0] ||
+                            (int8_t)pwt->chroma_weight[i][list][j][1] != pwt->chroma_weight[i][list][j][1])
+                            goto out_range_weight;
                         if (pwt->chroma_weight[i][list][j][0] != chroma_def ||
                             pwt->chroma_weight[i][list][j][1] != 0) {
                             pwt->use_weight_chroma        = 1;
@@ -104,6 +110,9 @@ int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
     }
     pwt->use_weight = pwt->use_weight || pwt->use_weight_chroma;
     return 0;
+out_range_weight:
+    avpriv_request_sample(logctx, "Out of range weight\n");
+    return AVERROR_INVALIDDATA;
 }
 
 /**

libavcodec/h264_slice.c

@@ -1780,9 +1780,12 @@ static int h264_slice_header_parse(const H264Context *h, H264SliceContext *sl,
     }
     if ((pps->weighted_pred && sl->slice_type_nos == AV_PICTURE_TYPE_P) ||
         (pps->weighted_bipred_idc == 1 &&
-         sl->slice_type_nos == AV_PICTURE_TYPE_B))
-        ff_h264_pred_weight_table(&sl->gb, sps, sl->ref_count,
+         sl->slice_type_nos == AV_PICTURE_TYPE_B)) {
+        ret = ff_h264_pred_weight_table(&sl->gb, sps, sl->ref_count,
                                   sl->slice_type_nos, &sl->pwt, h->avctx);
+        if (ret < 0)
+            return ret;
+    }
 
     sl->explicit_ref_marking = 0;
     if (nal->ref_idc) {