https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=7319

diff --git a/coders/mat.c b/coders/mat.c
index 3d797306e1324fa844f5dafac94a4c6f5cd40a18..8cadc50f0f49686df6074bc1ecfc581734492dee 100644 (file)
--- a/coders/mat.c
+++ b/coders/mat.c
@@ -537,6 +537,8 @@ ssize_t TotalSize = 0;
   while(*Size>0 && !EOFBlob(orig))
   {
     magick_size = ReadBlob(orig, (*Size < 16384) ? *Size : 16384, (unsigned char *) cache_block);
+    if (magick_size == 0)
+      break;
     zip_info.next_in = (Bytef *) cache_block;
     zip_info.avail_in = (uInt) magick_size;