Subject: backport of the CVE-2017-17969 fix from 7zip 18.00-beta
From: Antoine Beaupré <[email-masked]>
Date: Sun, 28 Jan 2018 21:19:50 +0100

---
 CPP/7zip/Compress/ShrinkDecoder.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/CPP/7zip/Compress/ShrinkDecoder.cpp b/CPP/7zip/Compress/ShrinkDecoder.cpp
index 80b7e67..4acdce5 100644
--- a/CPP/7zip/Compress/ShrinkDecoder.cpp
+++ b/CPP/7zip/Compress/ShrinkDecoder.cpp
@@ -121,7 +121,12 @@ HRESULT CDecoder::CodeReal(ISequentialInStream *inStream, ISequentialOutStream *
     {
       _stack[i++] = _suffixes[cur];
       cur = _parents[cur];
-    }
+      if (i >= kNumItems)
+        break;
+     }
+
+    if (i >= kNumItems)
+      break;
     
     _stack[i++] = (Byte)cur;
     lastChar2 = (Byte)cur;