[Patches] [ python-Patches-1380952 ] Fix bug read() would hang on ssl socket if settimeout() used

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Patches item #1380952, was opened at 2005-12-15 00:14
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Category: Modules
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Arkadiusz Miskiewicz (arekm)
Assigned to: Nobody/Anonymous (nobody)
Summary: Fix bug read() would hang on ssl socket if settimeout() used

Initial Comment:
The problem has occured many times before like bugs

https://sourceforge.net/tracker/?group_id=5470&atid=
105470&func=detail&aid=1353269

https://sourceforge.net/tracker/?group_id=5470&atid=
105470&func=detail&aid=977680

https://sourceforge.net/tracker/index.php?func=detail&
aid=1098618&group_id=5470&atid=105470

This also fixes this bug:
https://sourceforge.net/tracker/index.php?func=detail&
aid=1166206&group_id=5470&atid=105470

Example test:

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(30.0)
# connect to service which issues an welcome banner 
(without need to write anything)
s.connect(("gmail.org", 995))
ss = socket.ssl(s)
# read part of return welcome banner twice,# read part 
of return welcome banner twice
ss.read(1)
ss.read(1)
s.close()

it will cause
socket.sslerror: The read operation timed out         
on the second read()

This is because _ssl.so modules doesn't handle SSL 
reads properly. The problem is in Modules/_ssl.c:
PySSL_SSLread() we have:

        sockstate = check_socket_and_wait_for_timeout
(self->Socket, self->ssl, 0); // XXXX HERE XXX
        if (sockstate == SOCKET_HAS_TIMED_OUT) {
                PyErr_SetString(PySSLErrorObject, "The 
read operation timed out");
                Py_DECREF(buf);
                return NULL;
        }
        do {....

What will happen if SSL layer already read data and 
have that data in it's own buffers? The function check_
socket_and_wait_for_timeout() doing select(readfds) 
will wait forever until timeout occurs. The solution 
is to use http://www.openssl.org/docs/ssl/SSL_pending.
html function.

The attached patch fixes the problem and also adds 
test for python test suite.
                



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