Pickle in a POST/GET request give EOFError

Romaric DEFAUX rde at audaxis.com
Thu Nov 18 12:23:01 CET 2010


Sorry for this stupid question, but how can I convert unicode to string.
I ask that because I hit an error (perhaps a bug) in mod_wsgi, and that 
crash the apache process :

TypeError: sequence of string values expected, value of type unicode found
RuntimeError: generator ignored GeneratorExit
child pid 16211 exit signal Segmentation fault (11)

Romaric Defaux

Le 18/11/2010 11:26, Michael Ricordeau a écrit :
> When loading from json datas with simplejson, strings are unicode .
>
>
> Le Thu, 18 Nov 2010 11:22:30 +0100,
> Romaric DEFAUX<rde at audaxis.com>  a écrit :
>
>    
>> Hi again,
>>
>> I try simplejson, but I have a problem. (I just replace pickle
>> everywhere by simplejson)
>>
>> Here's a test I did :
>> # python
>> Python 2.5.2 (r252:60911, Jan 20 2010, 21:48:48)
>> [GCC 4.2.4 (Ubuntu 4.2.4-1ubuntu3)] on linux2
>> Type "help", "copyright", "credits" or "license" for more information.
>>   >>>  import simplejson
>>   >>>  disk_list = []
>>   >>>  disk = {}
>>   >>>  disk['name'] = "disk1"
>>   >>>  disk['size'] = "52428800"
>>   >>>  disk_list.append(disk)
>>   >>>  print disk_list
>> [{'name': 'disk1', 'size': '52428800'}]
>>   >>>  disk = {}
>>   >>>  disk['name'] = "disk2"
>>   >>>  disk['size'] = "647648"
>>   >>>  disk_list.append(disk)
>>   >>>  print disk_list
>> [{'name': 'disk1', 'size': '52428800'}, {'name': 'disk2', 'size': '647648'}]
>>   >>>  disk_list_json = simplejson.dumps(disk_list)
>>   >>>  print disk_list_json
>> [{"name": "disk1", "size": "52428800"}, {"name": "disk2", "size": "647648"}]
>>   >>>  disk_list2 = simplejson.loads(disk_list_json)
>>   >>>  print disk_list2
>> [{u'name': u'disk1', u'size': u'52428800'}, {u'name': u'disk2', u'size':
>> u'647648'}]
>>   >>>  print repr(disk_list_json)
>> '[{"name": "disk1", "size": "52428800"}, {"name": "disk2", "size":
>> "647648"}]'
>>
>> Explanation :
>> I "dumps" with json a list of dictionnaries into disk_list_json.
>> When I "loads" it, I don't get my list of dictionnaries like before (see
>> disk_list2). It adds "u" letter everywhere.
>> Why ?
>> Thanks for help !
>>
>> Romaric Defaux
>>
>> Le 18/11/2010 09:43, Michael Ricordeau a écrit :
>>      
>>> Hi,
>>>
>>> you can use json for passing list and dict .
>>> Pickle is dangerous .
>>>
>>> Instead of pickle.loads/pickle.dumps use json.loads and json.dumps
>>> (using stdlib json in python>= 2.6 or simplejson in python<   2.6)
>>>
>>> Regards
>>>
>>>
>>>
>>> Le Thu, 18 Nov 2010 09:29:00 +0100,
>>> Romaric DEFAUX<rde at audaxis.com>   a écrit :
>>>
>>>
>>>        
>>>> Le 17/11/2010 18:52, geremy condra a écrit :
>>>>
>>>>          
>>>>> On Wed, Nov 17, 2010 at 6:44 AM, Romaric DEFAUX<rde at audaxis.com>    wrote:
>>>>>
>>>>>
>>>>>            
>>>>>> Le 16/11/2010 17:47, Romaric DEFAUX a écrit :
>>>>>>
>>>>>>
>>>>>>              
>>>>>>> Hi everybody !
>>>>>>>
>>>>>>> First time I write to this mailing list :)
>>>>>>> I started writing in python last week, that's probably why I can't
>>>>>>> understand the following problem...
>>>>>>>
>>>>>>>
>>>>>>> I create a list called web_site_list.
>>>>>>> This list contain dictionaries called web_site.
>>>>>>> And some values in this dictionaries are list too.
>>>>>>>
>>>>>>> I do that in a function and I return this :
>>>>>>> return pickle.dumps(web_site_list)
>>>>>>>
>>>>>>> This is working fine :)
>>>>>>>
>>>>>>> If I do :
>>>>>>> print "%s" % pickle.loads(system.get_web_site_list())
>>>>>>>
>>>>>>> I've got the right stuffs. For example it returns :
>>>>>>> [{'documentroot_size': '120', 'servername': '---default---', 'client':
>>>>>>> 'undefined', 'documentroot': '/var/www/', 'client_contact': 'undefined',
>>>>>>> 'serveralias': []}]
>>>>>>>
>>>>>>> I send this to a web service. I send it like that :
>>>>>>> #I put it in params
>>>>>>> def system_updateweb_site(server, login, password):
>>>>>>>           params = {}
>>>>>>>           params['login'] = login
>>>>>>>           params['password'] = password
>>>>>>>           params['action'] = 'updateweb_site'
>>>>>>>           params['servername'] = get_servername()
>>>>>>>           params['hosted_web_site'] = get_web_site_list()
>>>>>>>           return call_system_ws(server, params)
>>>>>>>
>>>>>>> #Here's how I send it (I tried in GET and POST)
>>>>>>> def call_system_ws(host, params):
>>>>>>>           query_string = urllib.urlencode(params)
>>>>>>> #GET
>>>>>>> #       f = urllib.urlopen("http://%s/ws?%s" % (host, query_string))
>>>>>>> #POST
>>>>>>>           f = urllib.urlopen("http://%s/ws" % (host), query_string)
>>>>>>>           result = f.readline().strip()
>>>>>>>           if result == 'ERROR':
>>>>>>>                   msg = f.readline().strip()
>>>>>>>                   return (False, msg)
>>>>>>>           return (True, result)
>>>>>>>
>>>>>>>
>>>>>>> On the server side :
>>>>>>>                           if action == 'updateweb_site':
>>>>>>>                                   if not (fields.has_key('servername') and
>>>>>>> fields.has_key('hosted_web_site')):
>>>>>>>                                           raise WSError('missing parameter :
>>>>>>> servername or hosted_web_site')
>>>>>>>                                           log ('ERROR : missing parameter :
>>>>>>> servername or hosted_web_site')
>>>>>>>                                   else:
>>>>>>>
>>>>>>>     servername=g.db.escape_string(fields['servername'])
>>>>>>>
>>>>>>>     hosted_web_site=g.db.escape_string(fields['hosted_web_site'])
>>>>>>>                                           output =
>>>>>>> systemserver.updateweb_site(cursor, servername, hosted_web_site)
>>>>>>>
>>>>>>> In systemserver.py :
>>>>>>> def updateweb_site(cursor, host, hosted_web_site):
>>>>>>>           web_site_list = pickle.loads(hosted_web_site)
>>>>>>>           return "%s" % (web_site_list)
>>>>>>>
>>>>>>> I catch this error :*
>>>>>>>
>>>>>>> <type 'exceptions.EOFError'>*:
>>>>>>>
>>>>>>> args = ()
>>>>>>> message = ''
>>>>>>>
>>>>>>> Why ?
>>>>>>>
>>>>>>> If I just print hosted_web_site, I get this on my web page :
>>>>>>>
>>>>>>>
>>>>>>> (lp0\n(dp1\nS\'documentroot_size\'\np2\nS\'120\'\np3\nsS\'servername\'\np4\nS\'default\'\np5\nsS\'client\'\np6\nS\'undefined\'\np7\nsS\'documentroot\'\np8\nS\'/var/www/\'\np9\nsS\'client_contact\'\np10\ng7\nsS\'serveralias\'\np11\n(lp12\nsa.
>>>>>>>
>>>>>>> It's the "pickled view" of
>>>>>>> [{'documentroot_size': '120', 'servername': '---default---', 'client':
>>>>>>> 'undefined', 'documentroot': '/var/www/', 'client_contact': 'undefined',
>>>>>>> 'serveralias': []}]
>>>>>>>
>>>>>>> Can someone help me please ? I spend my afternoon to google to try to find
>>>>>>> a solution...
>>>>>>>
>>>>>>>
>>>>>>> Thanks in advance !!!
>>>>>>>
>>>>>>> Romaric Defaux
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>                
>>>>>> After entirely rewrite my code to not use Web service but socket (a real
>>>>>> client/server program) I finally found the problem... And it's not linked to
>>>>>> the POST or GET method...
>>>>>> It's because of that :
>>>>>> g.db.escape_string(fields['hosted_web_site'])
>>>>>> (escape_string is the function in MySQLdb library)
>>>>>> It escapes the simple quote of the pickled object, and break it...
>>>>>>
>>>>>> It's good to know, NEVER escape a pickled object :)
>>>>>>
>>>>>> Romaric Defaux
>>>>>>
>>>>>>
>>>>>>              
>>>>> I'm not sure I understand what you're doing here, but I trust you've
>>>>> read about and understand the security problems with pickle?
>>>>>
>>>>> Geremy Condra
>>>>>
>>>>>
>>>>>            
>>>> I read quickly the security problems with pickle. But I don't feel
>>>> concern about that because I run my program in a private network, not
>>>> over internet. And now I use socket to communicate on a non-standard
>>>> port, not anymore web service on the 80 port. If I plan to run it
>>>> through wan, I will encrypt datas for sure with SSL or something like
>>>> that :)
>>>>
>>>> Romaric Defaux
>>>>
>>>>
>>>>          
>>
>>      

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