[FFmpeg-cvslog] avcodec/h264: Check weight values to be within the specs limits.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Mar 21 23:46:14 2017 +0100| [08117a40157464f8a9dcc2df393fa5fe299c1e98] | committer: Michael Niedermayer

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/ffmpeg
Reviewed-by: "Ronald S. Bultje" <rsbultje at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=08117a40157464f8a9dcc2df393fa5fe299c1e98
---

 libavcodec/h264_parse.c | 9 +++++++++
 libavcodec/h264_slice.c | 7 +++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h264_parse.c b/libavcodec/h264_parse.c
index 0c87319..ea202e7 100644
--- a/libavcodec/h264_parse.c
+++ b/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;
 }
 
 /**
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index d4d31cc..34bd6cf 100644
--- a/libavcodec/h264_slice.c
+++ b/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) {