gif_deanimate(): Confirm that that we have enough data

... before doing any work.

Fixes a crash when fuzzing with an empty document.

Reported by: Joshua Rogers (Opera).

diff --git a/deanimate.c b/deanimate.c
index bc64de6..a6759da 100644 (file)
--- a/deanimate.c
+++ b/deanimate.c
@@ -333,6 +333,10 @@ int gif_deanimate(struct binbuffer *src, struct binbuffer *dst, int get_first_im
    {
       return 1;
    }
+   if (src->size <= 10)
+   {
+      return 1;
+   }
 
    c = buf_getbyte(src, 10);