avcodec/iff: Skip overflowing runs in decode_delta_d()

Fixes: Timeout (107sec - 75ms>
Fixes: 18812/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-6295585225441280

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/iff.c

@@ -1359,6 +1359,8 @@ static void decode_delta_d(uint8_t *dst,
             bytestream2_seek_p(&pb, (offset / planepitch_byte) * pitch + (offset % planepitch_byte) + k * planepitch, SEEK_SET);
             if (opcode >= 0) {
                 uint32_t x = bytestream2_get_be32(&gb);
+                if (opcode && 4 + (opcode - 1LL) * pitch > bytestream2_get_bytes_left_p(&pb))
+                    continue;
                 while (opcode && bytestream2_get_bytes_left_p(&pb) > 0) {
                     bytestream2_put_be32(&pb, x);
                     bytestream2_skip_p(&pb, pitch - 4);