wvdec: check for eof in wv_read_block_header()

Fixes Ticket #3865
Found-by: Piotr Bandurski <ami_stuff@o2.pl>
Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/wvdec.c

@@ -124,7 +124,7 @@ static int wv_read_block_header(AVFormatContext *ctx, AVIOContext *pb)
                    "Cannot determine additional parameters\n");
             return AVERROR_INVALIDDATA;
         }
-        while (avio_tell(pb) < block_end) {
+        while (avio_tell(pb) < block_end && !avio_feof(pb)) {
             int id, size;
             id   = avio_r8(pb);
             size = (id & 0x80) ? avio_rl24(pb) : avio_r8(pb);