4xm: add assert to check that the pointer from read_huffman_tables is within the array

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 2 insertions, 0 deletions

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index 39254f7c07..9ea84364b0 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -760,6 +760,8 @@ static int decode_i_frame(FourXContext *f, const uint8_t *buf, int length)
     if (!prestream)
         return -1;
 
+    av_assert0(prestream <= buf + length);
+
     init_get_bits(&f->gb, buf + 4, 8 * bitstream_size);
 
     prestream_size = length + buf - prestream;