Python module rewritten in pure Python

README

@@ -582,15 +582,16 @@ libsf_ai_preproc.la  if  you  want to use some of the functions from the module,
  database,       the       current       correlations,      and      so      on.
 
 It  is  also possible to write your own modules in Python language. See the file
-'example.py'  in  corr_modules/  for  a quick overview. All you need to do is to
-declare  in  your  module the functions AI_corr_index (taking two arguments, two
- alert    descriptions)   and   AI_corr_index_weight   (taking   no   argument),
- both   returning   a   real  value  descibing,  respectively,  the  correlation
- value  between  the  two  alerts  and  the  weight  of that index, both between
- 0 and  1.  You  can  also  access  the  alert  information  and  all the alerts
- acquired   so  far  by  the  module  by  importing  in  your  Python  code  the
- 'snortai'   module.   You   can   compile  it  and  install  it  by  moving  to
- 'pymodule/'                 directory                and                running
+'example_module.py'  in  corr_modules/  for  a  quick  overview. All you need to
+do  is  to  declare  in  your  module  the  functions  AI_corr_index (taking two
+arguments,      two     alert     descriptions)     and     AI_corr_index_weight
+(taking     no    argument),    both    returning   a   real   value   descibing,
+respectively,    the   correlation   value   between  the  two  alerts  and  the
+weight  of  that   index,  both  between  0  and  1.  You  can  also  access the
+alert   information    and  all  the  alerts  acquired  so  far  by  the  module
+by   importing   in    your   Python   code   the   'snortai'  module.  You  can
+compile     it     and      install     it     by    moving    to    'pymodule/'
+directory and running
 
 $ python setup.py build
 $ [sudo] python setup.py install
@@ -604,10 +605,10 @@ alerts = snortai.alerts()
 for alert in alerts:
 	# Access the alerts information
 
-The  fields  in  the  alert  class  can  be  viewed  in  pymodule/module.py  and
-corr_modules/example.py  examples.  Take  these  files as guides for interfacing
-your  Python  scripts  with SnortAI module or writing new correlation modules in
-Python.
+The     fields     in     the     alert     class     can     be    viewed    in
+pymodule/test.py   and   corr_modules/example_module.py   examples.  Take  these
+files  as  guides  for  interfacing  your  Python  scripts  with  SnortAI module
+or       writing       new       correlation       modules       in      Python.
 
 
 ===========================

corr_modules/example.py

@@ -1,28 +0,0 @@
-#!/usr/bin/python
-
-# Example correlation index in Python
-
-# XXX You may have an 'undefined reference to PyNone_Struct
-# after running Snort with your module, you're facing an
-# annoying bug due to the dynamically linked Python library.
-# I'm sorry, but I'm still looking for a solution for this,
-# and anyway it only happens when you import the module
-# 'snortai'
-
-# import snortai
-
-# Function that takes two alerts as arguments (arguments of
-# alert object: 
-# id, gid, sid, rev, description, priority, classification,
-# timestamp, from, to, from_port, to_port, latitude,
-# longitude, alerts_count) and returns a correlation index
-# between 0 and 1 expressing how correlated these two alerts are
-
-def AI_corr_index ( alert1, alert2 ):
-	return 0.0
-
-# Return the weight of this index, between 0 and 1
-
-def AI_corr_index_weight():
-	return 0.0
-

corr_modules/example_module.py

@@ -0,0 +1,34 @@
+#!/usr/bin/python
+
+# Example correlation index in Python
+# It simply does nothing (both the correlation index
+# and the correlation weight are zero), use it as
+# track for writing your own correlation modules
+
+# Go to pymodule and run
+# $ python setup.py build
+# $ [sudo] python setup.py install
+# in order to build and install the snortai Python module
+import snortai
+
+# Function that takes two alerts as arguments (arguments of
+# alert object: 
+# id, gid, sid, rev, description, priority, classification,
+# timestamp, src_addr, dst_addr, src_port, dst_port, latitude,
+# longitude) and returns a correlation index between 0 and 1
+# expressing how correlated these two alerts are
+
+def AI_corr_index ( alert1, alert2 ):
+	# alerts = snortai.alerts()
+	# for alert in alerts:
+	# 	do_something
+	#
+	# print alert1.gid, alert1.sid, alert1.rev
+	# print alert2.gid, alert2.sid, alert2.rev
+	return 0.0
+
+# Return the weight of this index, between 0 and 1
+
+def AI_corr_index_weight():
+	return 0.0
+

correlation.c

@@ -385,8 +385,8 @@ AI_alert_correlation_thread ( void *arg )
 	double (**corr_weights)() = NULL;
 
 	#ifdef HAVE_LIBPYTHON2_6
-	PyAlert *pyA = NULL,
-		   *pyB = NULL;
+	PyObject *pyA = NULL,
+		    *pyB = NULL;
 
 	PyObject *pArgs = NULL,
 		    *pRet  = NULL;
@@ -556,7 +556,8 @@ AI_alert_correlation_thread ( void *arg )
 								}
 							}
 
-							free ( pyA ); free ( pyB );
+							Py_DECREF ( pyA ); Py_DECREF ( pyB );
+							/* free ( pyA ); free ( pyB ); */
 							pyA = NULL; pyB = NULL;
 						}
 					}

modules.c

@@ -99,37 +99,61 @@ AI_get_py_weights ( size_t *n_functions )
 /**
  * \brief  Convert an AI_snort_alert object to a PyAlert object that can be managed by a Python module
  * \param  alert 	AI_snort_alert object to be converted
- * \return A PyAlert object wrapping the original AI_snort_alert object
+ * \return A PyObject object wrapping the original AI_snort_alert object
  */
 
-PyAlert*
+PyObject*
 AI_alert_to_pyalert ( AI_snort_alert *alert )
 {
-	PyAlert *pyalert = NULL;
+	PyObject *pyalert = NULL;
+
+	PyObject *pMod  = NULL,
+		    *pObj  = NULL,
+		    *pArgs = NULL;
+
 	char src_addr[INET_ADDRSTRLEN] = { 0 },
 		dst_addr[INET_ADDRSTRLEN] = { 0 };
 	
-	if ( !( pyalert = (PyAlert*) malloc ( sizeof ( PyAlert ))))
+	if ( !( pMod = PyImport_ImportModule ( "snortai" )))
 	{
-		AI_fatal_err ( "Fatal dynamic memory allocation error", __FILE__, __LINE__ );
+		PyErr_Print();
+		AI_fatal_err ( "Could not load Python module 'snortai'", __FILE__, __LINE__ );
 	}
 
-	inet_ntop ( AF_INET, &(alert->ip_src_addr), src_addr, INET_ADDRSTRLEN );
-	inet_ntop ( AF_INET, &(alert->ip_dst_addr), dst_addr, INET_ADDRSTRLEN );
+	if ( !( pObj = PyObject_GetAttrString ( pMod, "alert" )))
+	{
+		PyErr_Print();
+		AI_fatal_err ( "'alert' object not found in the Python module 'snortai'", __FILE__, __LINE__ );
+	}
 
-	pyalert->classification = alert->classification ? PyString_FromString ( alert->classification ) : Py_None;
-	pyalert->clusteredAlertsCount = alert->grouped_alerts_count;
-	pyalert->desc = alert->desc ? PyString_FromString ( alert->desc ) : Py_None;
-	pyalert->gid = alert->gid;
-	pyalert->ip_src_addr = ( strlen ( src_addr ) > 0 ) ? PyString_FromString ( src_addr ) : Py_None;
-	pyalert->ip_dst_addr = ( strlen ( dst_addr ) > 0 ) ? PyString_FromString ( dst_addr ) : Py_None;
-	pyalert->priority = alert->priority;
-	pyalert->rev = alert->rev;
-	pyalert->sid = alert->sid;
-	pyalert->tcp_src_port = ntohs ( alert->tcp_src_port );
-	pyalert->tcp_dst_port = ntohs ( alert->tcp_dst_port );
-	pyalert->timestamp = alert->timestamp;
+	Py_DECREF ( pMod );
 
+	if ( !( pArgs = Py_BuildValue ( "(OOOOOOOOOOOOO)",
+		Py_None,
+		PyLong_FromUnsignedLong ( alert->gid ),
+		PyLong_FromUnsignedLong ( alert->sid ),
+		PyLong_FromUnsignedLong ( alert->rev ),
+		PyLong_FromUnsignedLong ((long int) alert->priority ),
+		alert->classification ? PyString_FromString ( alert->classification ) : Py_None,
+		alert->desc ? PyString_FromString ( alert->desc ) : Py_None,
+		PyString_FromString ( src_addr ),
+		PyString_FromString ( dst_addr ),
+		PyLong_FromLong ((long int) ntohs ( alert->tcp_src_port )),
+		PyLong_FromLong ((long int) ntohs ( alert->tcp_dst_port )),
+		Py_None,
+		Py_None )))
+	{
+		PyErr_Print();
+		AI_fatal_err ( "Could not initialize the argument list for calling the Python 'alert' constructor", __FILE__, __LINE__ );
+	}
+
+	if ( !( pyalert = PyObject_CallObject ( pObj, pArgs )))
+	{
+		PyErr_Print();
+		AI_fatal_err ( "Could not call the constructor over the Python object 'alert'", __FILE__, __LINE__ );
+	}
+
+	Py_DECREF ( pArgs ); Py_DECREF ( pObj );
 	return pyalert;
 }		/* -----  end of function AI_alert_to_pyalert  ----- */
 #endif

pymodule/README

@@ -12,9 +12,10 @@ alerts = snortai.alerts()
 
 for alert in alerts:
 	# Access the information
+	print alert.gid, alert.sid, alert.rev
 
 The alert class has the following members:
 
 # id, gid, sid, rev, description, priority, classification, timestamp
-# from, to, from_port, to_port, latitude, longitude, alerts_count
+# src_addr, dst_addr, src_port, dst_port, latitude, longitude
 

pymodule/module.py

@@ -1,21 +0,0 @@
-#!/usr/bin/python
-
-# Compile snortai module by typing, in pymodule directory:
-# $ python setup.py build
-# $ [sudo] python setup.py install
-import snortai
-
-# Get the alerts from Snort module as tuple
-# (IMPORTANT: Snort and SnortAI module, as well as
-# the web server running on top of the module, must
-# be running in order to have this call successful)
-alerts = snortai.alerts()
-
-# Navigate the tuple of alerts
-# Fields:
-# id, gid, sid, rev, description, priority, classification,
-# timestamp, from, to, from_port, to_port, latitude,
-# longitude, alerts_count
-for alert in alerts:
-	print alert.gid, alert.sid, alert.rev, alert.description
-

pymodule/setup.py

@@ -1,20 +1,6 @@
-#!/usr/bin/python
+#!/usr/bin/env python
 
 from distutils.core import setup, Extension
-import commands
-import re
-
-xml_include = commands.getoutput ( 'pkg-config --cflags libxml-2.0' )
-m = re.match ( '^-I\s*(.+?)\s*$', xml_include )
-
-if m:
-	xml_include = m.group ( 1 )
-
-xml_libs = commands.getoutput ( 'pkg-config --libs libxml-2.0' )
-m = re.match ( '^-l\s*(.+?)\s*$', xml_libs )
-
-if m:
-	xml_libs = m.group ( 1 )
 
 setup (
 	name = 'snortai',
@@ -22,13 +8,6 @@ setup (
 	description = 'Python interface to SnortAI module',
 	author = 'Fabio "BlackLight" Manganiello',
 	author_email = 'blacklight@autistici.org',
-	ext_modules = [
-		Extension (
-			'snortai',
-			sources = ['snortai_module.c'],
-			include_dirs = ['..', '../include', '../uthash', xml_include],
-			libraries = [xml_libs]
-		)
-	]
+	packages = ['snortai']
 )
 

pymodule/snortai/__init__.py

@@ -0,0 +1,57 @@
+#!/usr/bin/python
+
+import urllib
+import xml.dom.minidom as xml
+
+class alert:
+	"""Class that models a Snort alert type"""
+	def __init__ ( self, id = None, gid = None, sid = None, rev = None,
+			priority = None, classification = None, description = None,
+			src_addr = None, dst_addr = None, src_port = None, dst_port = None,
+			latitude = None, longitude = None, ):
+		self.id = id
+		self.gid = gid
+		self.sid = sid
+		self.rev = rev
+		self.priority = priority
+		self.latitude = latitude
+		self.longitude = longitude
+		self.description = description
+		self.classification = classification
+		self.src_addr = src_addr
+		self.dst_addr = dst_addr
+		self.src_port = src_port
+		self.dst_port = dst_port
+
+resource_url = 'http://localhost:7654/alerts.cgi'
+response_text = None;
+
+def alerts():
+	url = urllib.urlopen ( resource_url )
+	response_text = url.read()
+	document = xml.parseString ( response_text )
+	alerts = []
+
+	for element in document.getElementsByTagName ( 'alert' ):
+		a = alert()
+
+		for attr in element.attributes.keys():
+			if attr in ['id', 'gid', 'sid', 'rev', 'priority', 'latitude', 'longitude', 'classification']:
+				setattr ( a, attr, element.attributes[attr].value )
+			elif attr == 'date':
+				setattr ( a, 'timestamp',  element.attributes[attr].value )
+			elif attr == 'label':
+				setattr ( a, 'description', element.attributes[attr].value )
+			elif attr == 'from':
+				setattr ( a, 'src_addr', element.attributes[attr].value )
+			elif attr == 'to':
+				setattr ( a, 'dst_addr', element.attributes[attr].value )
+			elif attr == 'from_port':
+				setattr ( a, 'src_port', element.attributes[attr].value )
+			elif attr == 'to_port':
+				setattr ( a, 'dst_port', element.attributes[attr].value )
+
+		alerts.append ( a )
+
+	return alerts
+

pymodule/snortai_module.c

@@ -17,6 +17,12 @@
  * =====================================================================================
  */
 
+/* This is the old C-based module for Python interface to SnortAI
+ * and it is now completely *DEPRECATED* and kept only for
+ * back-compatibility purposes. Use the pure Python interface
+ * instead, running python setup.py build && sudo python setup.py install
+ * will build and install the new Python module */
+
 #ifndef HAVE_LIBPYTHON2_6
 #define HAVE_LIBPYTHON2_6 1
 #endif

pymodule/test.py

@@ -0,0 +1,8 @@
+#!/usr/bin/python
+
+import snortai
+
+alerts = snortai.alerts()
+
+for alert in alerts:
+	print alert.gid, alert.sid, alert.rev

spp_ai.h

@@ -31,6 +31,25 @@
 #include	<netinet/in.h>
 #include	<pthread.h>
 
+/*******************************************/
+#ifdef HAVE_LIBPYTHON2_6
+/* Avoid conflicts with Snort header files */
+#ifdef _POSIX_C_SOURCE
+#undef _POSIX_C_SOURCE
+#endif
+
+#ifdef _XOPEN_C_SOURCE
+#undef _XOPEN_C_SOURCE
+#endif
+
+#ifdef _XOPEN_SOURCE
+#undef _XOPEN_SOURCE
+#endif
+
+#include	<Python.h>
+#endif
+/*******************************************/
+
 #define 	PRIVATE 		static
 
 /** Default interval in seconds for the thread cleaning up TCP streams */
@@ -543,61 +562,6 @@ typedef struct  {
 	UT_hash_handle             hh;
 } AI_alert_type_pair;
 /*****************************************************************/
-#ifdef HAVE_LIBPYTHON2_6
-
-/*******************************************/
-/* Avoid conflicts with Snort header files */
-#ifdef _POSIX_C_SOURCE
-#undef _POSIX_C_SOURCE
-#endif
-
-#ifdef _XOPEN_C_SOURCE
-#undef _XOPEN_C_SOURCE
-#endif
-
-#ifdef _XOPEN_SOURCE
-#undef _XOPEN_SOURCE
-#endif
-/*******************************************/
-
-#include	<Python.h>
-
-/** Definition of the alert type for Python binding */
-typedef struct _PyAlert
-{
-	PyObject_HEAD
-
-	unsigned int id;
-
-	/* Identifiers of the alert */
-	unsigned int gid;
-	unsigned int sid;
-	unsigned int rev;
-
-	/* Snort priority, description,
-	 * classification and timestamp
-	 * of the alert */
-	unsigned short  priority;
-	PyObject*       desc;
-	PyObject*       classification;
-	time_t          timestamp;
-
-	PyObject*       ip_src_addr;
-	PyObject*       ip_dst_addr;
-	unsigned short  tcp_src_port;
-	unsigned short  tcp_dst_port;
-
-	double          latitude;
-	double          longitude;
-
-	unsigned int    clusteredAlertsCount;
-
-	struct _PyAlert *next;
-} PyAlert;
-
-#endif
-/*****************************************************************/
-
 
 /** Enumeration for describing the table in the output database */
 enum  { ALERTS_TABLE, IPV4_HEADERS_TABLE, TCP_HEADERS_TABLE, PACKET_STREAMS_TABLE, CLUSTERED_ALERTS_TABLE, CORRELATED_ALERTS_TABLE, N_TABLES };
@@ -678,7 +642,7 @@ double(**AI_get_corr_weights ( size_t* ))( void );
 
 PyObject** AI_get_py_functions ( size_t* );
 PyObject** AI_get_py_weights ( size_t* );
-PyAlert* AI_alert_to_pyalert ( AI_snort_alert* );
+PyObject* AI_alert_to_pyalert ( AI_snort_alert* );
 
 #endif