From 37d3ff14871a25429fb93167aeace0589be45426 Mon Sep 17 00:00:00 2001
From: Nadeem Vawda <nadeem.vawda@gmail.com>
Date: Sun, 5 Aug 2012 02:19:09 +0200
Subject: #15546: Fix {GzipFile,LZMAFile}.read1()'s handling of pathological
 input data.

---
 Lib/gzip.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'Lib/gzip.py')

diff --git a/Lib/gzip.py b/Lib/gzip.py
index 8b8942642e..5bcfe6123a 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -385,7 +385,10 @@ class GzipFile(io.BufferedIOBase):
             return b''
 
         try:
-            self._read()
+            # For certain input data, a single call to _read() may not return
+            # any data. In this case, retry until we get some data or reach EOF.
+            while self.extrasize <= 0:
+                self._read()
         except EOFError:
             pass
         if size < 0 or size > self.extrasize:
-- 
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