From 53b1e703ab24c8e6b67749462df39c73de816fb8 Mon Sep 17 00:00:00 2001
From: Marrub <marrub.xz@gmail.com>
Date: Tue, 12 Mar 2019 16:28:34 -0400
Subject: [PATCH] fix load_zlib_header

---
 source/marathon/defl.rs | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/source/marathon/defl.rs b/source/marathon/defl.rs
index 72b9404..23f60d2 100644
--- a/source/marathon/defl.rs
+++ b/source/marathon/defl.rs
@@ -18,10 +18,18 @@ pub fn load_zlib_header(b: &[u8]) -> ResultS<usize>
    }
 
    let cm    = cmf & CM;
-   let cinfo = cmf & CINFO >> 4;
+   let cinfo = cmf & CINFO;
 
-   if cm != 8 || fcheck % 31 != 0 || cinfo > 7 {
-      bail!("not zlib format");
+   if cm != 8 {
+      bail!("unknown compression method");
+   }
+
+   if cinfo > 7 << 4 {
+      bail!("lz77 window size logarithm is invalid");
+   }
+
+   if fcheck % 31 != 0 {
+      bail!("invalid fcheck");
    }
 
    if flg & FDICT != 0 {