avformat/mxfdec: More offset_temp checks

Fixes: signed integer overflow: 9223372036854775807 - -1927491430256034080 cannot be represented in type 'long'
Fixes: 70607/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-5282235077951488

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

libavformat/mxfdec.c

@@ -1921,6 +1921,11 @@ static int mxf_edit_unit_absolute_offset(MXFContext *mxf, MXFIndexTable *index_t
             return mxf_absolute_bodysid_offset(mxf, index_table->body_sid, offset_temp, offset_out, partition_out);
         } else {
             /* EditUnitByteCount == 0 for VBR indexes, which is fine since they use explicit StreamOffsets */
+            if (s->edit_unit_byte_count && (s->index_duration > INT64_MAX / s->edit_unit_byte_count ||
+                s->edit_unit_byte_count * s->index_duration > INT64_MAX - offset_temp)
+            )
+                return AVERROR_INVALIDDATA;
+
             offset_temp += s->edit_unit_byte_count * s->index_duration;
         }
     }