[Python-bugs-list] [ python-Bugs-781722 ] py-2.3 socket.inet_pton() segfault.

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Bugs item #781722, was opened at 2003-08-01 16:40
Message generated for change (Settings changed) made by nnorwitz
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=781722&group_id=5470

Category: Extension Modules
Group: Python 2.3
Status: Open
Resolution: None
>Priority: 7
Submitted By: Wojtek Walczak (gminick)
Assigned to: Nobody/Anonymous (nobody)
Summary: py-2.3 socket.inet_pton() segfault.

Initial Comment:
It works (read: segfaults) only when compiled without 
IPv6 support. Code to exploit this bug:

import socket
socket.inet_pton(socket.AF_INET6, '5aef:2b::8')

It segfaults because of that code from 
Modules/socketmodule.c:
---
#ifdef ENABLE_IPV6
   char packed[MAX(sizeof(struct in_addr), sizeof(struct 
in6_addr))];
#else
   char packed[sizeof(struct in_addr)];
#endif
   if (!PyArg_ParseTuple(args, "is:inet_pton", &af, &ip)) {
      return NULL;
   }

   retval = inet_pton(af, ip, packed);
---
Because IPv6 is disabled packet is defined in that way:

char packed[sizeof(struct in_addr)];

but we're still able to ask inet_pton() to convert some 
IPv6 address because socket.AF_INET6 constant is 
available, but packet buffer is too small to hold IPv6 data.
A simple patch:
#---------------------------------
--- ../../orig/Python-2.3/Modules/socketmodule.c        
Thu Jul 17 18:58:48 2003
+++ socketmodule.c      Fri Aug  1 22:13:30 2003
@@ -2962,6 +2962,14 @@
                return NULL;
        }
 
+#ifndef ENABLE_IPV6
+   if(af == AF_INET6) {
+      PyErr_SetString(socket_error,
+         "can't use AF_INET6, IPv6 is disabled");
+      return NULL;
+   }
+#endif
+
        retval = inet_pton(af, ip, packed);
        if (retval < 0) {
                PyErr_SetFromErrno(socket_error);
#----------------------------------

Sorry, if you know about this one already.

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