From: Georg Brandl <georg@python.org>
Date: Mon, 4 Jul 2005 17:16:07 +0000 (+0000)
Subject: bug #1177468: don't cache /dev/urandom file descriptor in os.urandom
X-Git-Tag: v2.5a0~1615
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9e43acf2f31e67a976475c2c9f8674dd27571cc6;p=thirdparty%2FPython%2Fcpython.git

bug #1177468: don't cache /dev/urandom file descriptor in os.urandom
---

diff --git a/Lib/os.py b/Lib/os.py
index 5824609b14da..bf1b08638333 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -715,22 +715,18 @@ except NameError: # statvfs_result may not exist
     pass
 
 if not _exists("urandom"):
-    _urandomfd = None
     def urandom(n):
         """urandom(n) -> str
 
         Return a string of n random bytes suitable for cryptographic use.
 
         """
-        global _urandomfd
-        if _urandomfd is None:
-            try:
-                _urandomfd = open("/dev/urandom", O_RDONLY)
-            except:
-                _urandomfd = NotImplementedError
-        if _urandomfd is NotImplementedError:
+        try:
+            _urandomfd = open("/dev/urandom", O_RDONLY)
+        except:
             raise NotImplementedError("/dev/urandom (or equivalent) not found")
         bytes = ""
         while len(bytes) < n:
             bytes += read(_urandomfd, n - len(bytes))
+        close(_urandomfd)
         return bytes
diff --git a/Misc/NEWS b/Misc/NEWS
index 8d86efde286c..bcc696ae9752 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -150,6 +150,9 @@ Extension Modules
 Library
 -------
 
+- Bug #1177468: Don't cache the /dev/urandom file descriptor for os.urandom,
+  as this can cause problems with apps closing all file descriptors.
+
 - Bug #839151: Fix an attempt to access sys.argv in the warnings module
   though this can be missing in embedded interpreters