From 4346a16853e19b45787ce933666026903fb8f3f8 Mon Sep 17 00:00:00 2001
From: Mark Adler <madler@alumni.caltech.edu>
Date: Tue, 17 Apr 2018 22:44:41 -0700
Subject: [PATCH] Assure that the number of bits for deflatePrime() is valid.

---
 deflate.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/deflate.c b/deflate.c
index 3db6d75..a4b0977 100644
--- a/deflate.c
+++ b/deflate.c
@@ -604,7 +604,8 @@ int ZEXPORT deflatePrime (strm, bits, value)
 
     if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
     s = strm->state;
-    if (s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
+    if (bits < 0 || bits > 16 ||
+        s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
         return Z_BUF_ERROR;
     do {
         put = Buf_size - s->bi_valid;
-- 
2.27.0