Work in progress to sandbox the uses of eval in LMS.

common/lib/capa/capa/capa_problem.py

@@ -22,7 +22,6 @@ import numpy
 import os
 import random
 import re
-import scipy
 import struct
 import sys
 
@@ -30,6 +29,7 @@ from lxml import etree
 from xml.sax.saxutils import unescape
 from copy import deepcopy
 
+<<<<<<< HEAD
 import chem
 import chem.miller
 import chem.chemcalc
@@ -38,8 +38,9 @@ import verifiers
 import verifiers.draganddrop
 
 import calc
+=======
+>>>>>>> Work in progress to sandbox the uses of eval in LMS.
 from .correctmap import CorrectMap
-import eia
 import inputtypes
 import customrender
 from .util import contextualize_text, convert_files_to_filenames
@@ -48,6 +49,8 @@ import xqueue_interface
 # to be replaced with auto-registering
 import responsetypes
 
+from codejail.safe_exec import safe_exec
+
 # dict of tagname, Response Class -- this should come from auto-registering
 response_tag_dict = dict([(x.response_tag, x) for x in responsetypes.__all__])
 
@@ -63,6 +66,7 @@ html_transforms = {'problem': {'tag': 'div'},
                    "math": {'tag': 'span'},
                    }
 
+<<<<<<< HEAD
 global_context = {'random': random,
                   'numpy': numpy,
                   'math': math,
@@ -73,6 +77,20 @@ global_context = {'random': random,
                   'chemtools': chem.chemtools,
                   'miller': chem.miller,
                   'draganddrop': verifiers.draganddrop}
+=======
+safe_exec_assumed_imports = [
+    "random",
+    "numpy",
+    "math",
+    "scipy",
+    "calc",
+    "eia",
+    ("chemcalc", "chem.chemcalc"),
+    ("chemtools", "chem.chemtools"),
+    ("miller", "chem.miller"),
+    ("draganddrop", "verifiers.draganddrop"),
+]
+>>>>>>> Work in progress to sandbox the uses of eval in LMS.
 
 # These should be removed from HTML output, including all subelements
 html_problem_semantics = ["codeparam", "responseparam", "answer", "script", "hintgroup", "openendedparam", "openendedrubric"]
@@ -144,7 +162,7 @@ class LoncapaProblem(object):
         self._process_includes()
 
         # construct script processor context (eg for customresponse problems)
-        self.context = self._extract_context(self.tree, seed=self.seed)
+        self.context = self._extract_context(self.tree)
 
         # Pre-parse the XML tree: modifies it to add ID's and perform some in-place
         # transformations.  This also creates the dict (self.responders) of Response
@@ -451,7 +469,7 @@ class LoncapaProblem(object):
 
         return path
 
-    def _extract_context(self, tree, seed=struct.unpack('i', os.urandom(4))[0]):  # private
+    def _extract_context(self, tree):
         '''
         Extract content of <script>...</script> from the problem.xml file, and exec it in the
         context of this problem.  Provides ability to randomize problems, and also set
@@ -460,14 +478,18 @@ class LoncapaProblem(object):
         Problem XML goes to Python execution context. Runs everything in script tags.
         '''
         random.seed(self.seed)
-        # save global context in here also
-        context = {'global_context': global_context}
-
-        # initialize context to have stuff in global_context
-        context.update(global_context)
 
+        # TODO: REMOVE THIS COMMENTED OUT CODE.
+        ## save global context in here also
+        #context = {'global_context': global_context}
+        #
+        ## initialize context to have stuff in global_context
+        #context.update(global_context)
+        #
         # put globals there also
-        context['__builtins__'] = globals()['__builtins__']
+        #context['__builtins__'] = globals()['__builtins__']
+
+        context = {}
 
         # pass instance of LoncapaProblem in
         context['the_lcp'] = self
@@ -501,7 +523,7 @@ class LoncapaProblem(object):
             context['script_code'] += code
             try:
                 # use "context" for global context; thus defs in code are global within code
-                exec code in context, context
+                safe_exec(code, context, future_division=True, assumed_imports=safe_exec_assumed_imports)
             except Exception as err:
                 log.exception("Error while execing script code: " + code)
                 msg = "Error while executing script code: %s" % str(err).replace('<', '&lt;')

common/lib/capa/capa/responsetypes.py

@@ -37,6 +37,8 @@ from lxml import etree
 from lxml.html.soupparser import fromstring as fromstring_bs     # uses Beautiful Soup!!! FIXME?
 import xqueue_interface
 
+from codejail.safe_exec import safe_exec
+
 log = logging.getLogger(__name__)
 
 
@@ -968,14 +970,20 @@ def sympy_check2():
             cfn = xml.get('cfn')
             if cfn:
                 log.debug("cfn = %s" % cfn)
-                if cfn in self.context:
-                    self.code = self.context[cfn]
-                else:
-                    msg = "%s: can't find cfn %s in context" % (
-                        unicode(self), cfn)
-                    msg += "\nSee XML source line %s" % getattr(self.xml, 'sourceline',
-                                                                '<unavailable>')
-                    raise LoncapaProblemError(msg)
+
+                def make_check_function(script_code, cfn):
+                    def check_function(expect, ans):
+                        code = (script_code + "\n" +
+                                "cfn_return = %s(expect, ans)\n" % cfn)
+                        globals_dict = {
+                            'expect': expect,
+                            'ans': ans,
+                        }
+                        safe_exec(code, globals_dict)
+                        return globals_dict['cfn_return']
+                    return check_function
+
+                self.code = make_check_function(self.context['script_code'], cfn)
 
         if not self.code:
             if answer is None:
@@ -1074,6 +1082,7 @@ def sympy_check2():
         # exec the check function
         if isinstance(self.code, basestring):
             try:
+                raise Exception("exec 1")
                 exec self.code in self.context['global_context'], self.context
                 correct = self.context['correct']
                 messages = self.context['messages']
@@ -1083,32 +1092,15 @@ def sympy_check2():
                 self._handle_exec_exception(err)
 
         else:
-            # self.code is not a string; assume its a function
+            # self.code is not a string; it's a function we created earlier.
 
             # this is an interface to the Tutor2 check functions
             fn = self.code
             ret = None
             log.debug(" submission = %s" % submission)
             try:
-                answer_given = submission[0] if (
-                    len(idset) == 1) else submission
-                # handle variable number of arguments in check function, for backwards compatibility
-                # with various Tutor2 check functions
-                args = [self.expect, answer_given,
-                        student_answers, self.answer_ids[0]]
-                argspec = inspect.getargspec(fn)
-                nargs = len(argspec.args) - len(argspec.defaults or [])
-                kwargs = {}
-                for argname in argspec.args[nargs:]:
-                    kwargs[argname] = self.context[
-                        argname] if argname in self.context else None
-
-                log.debug('[customresponse] answer_given=%s' % answer_given)
-                log.debug('nargs=%d, args=%s, kwargs=%s' % (
-                    nargs, args, kwargs))
-
-                ret = fn(*args[:nargs], **kwargs)
-
+                answer_given = submission[0] if (len(idset) == 1) else submission
+                ret = fn(self.expect, answer_given)
             except Exception as err:
                 self._handle_exec_exception(err)
 
@@ -1265,6 +1257,7 @@ class SymbolicResponse(CustomResponse):
     def setup_response(self):
         self.xml.set('cfn', 'symmath_check')
         code = "from symmath import *"
+        raise Exception("exec 2")
         exec code in self.context, self.context
         CustomResponse.setup_response(self)
 
@@ -1378,6 +1371,7 @@ class CodeResponse(LoncapaResponse):
         penv = {}
         penv['__builtins__'] = globals()['__builtins__']
         try:
+            raise Exception("exec 3")
             exec(code, penv, penv)
         except Exception as err:
             log.error(
@@ -1925,18 +1919,12 @@ class SchematicResponse(LoncapaResponse):
             self.code = answer.text
 
     def get_score(self, student_answers):
-        from capa_problem import global_context
-        submission = [json.loads(student_answers[
-                                 k]) for k in sorted(self.answer_ids)]
+        #from capa_problem import global_context
+        submission = [
+            json.loads(student_answers[k]) for k in sorted(self.answer_ids)
+        ]
         self.context.update({'submission': submission})
-
-        try:
-            exec self.code in global_context, self.context
-
-        except Exception as err:
-            _, _, traceback_obj = sys.exc_info()
-            raise ResponseError, ResponseError(err.message), traceback_obj
-
+        safe_exec(self.code, {}, self.context)
         cmap = CorrectMap()
         cmap.set_dict(dict(zip(sorted(
             self.answer_ids), self.context['correct'])))

common/lib/codejail/codejail/safe_exec.py

@@ -19,6 +19,11 @@ def jsonable_dict(d):
     return jd
 
 def safe_exec(code, globals_dict, locals_dict=None, future_division=False, assumed_imports=None):
+    """Execute code safely.
+
+    Returns None.  The code can modify globals in `global_dict`.
+
+    """
     if future_division:
         code = "from __future__ import division\n" + code
 

common/test/data/embedded_python/course/2013_Spring.xml

 <course>
-  <chapter url_name="GradedChapter">
+  <chapter url_name="EmbeddedPythonChapter">
 
     <vertical url_name="Homework1">
-      <problem url_name="H1P1">
+      <problem url_name="schematic_problem">
           <schematicresponse>
             <center>
-                <schematic height="500" width="600" parts="g,n,s" analyses="dc,tran" submit_analyses="{&quot;tran&quot;:[[&quot;Z&quot;,0.0000004,0.0000009,0.0000014,0.0000019,0.0000024,0.0000029,0.0000034,0.000039]]}" initial_value="[[&quot;w&quot;,[112,96,128,96]],[&quot;w&quot;,[256,96,240,96]],[&quot;w&quot;,[192,96,240,96]],[&quot;s&quot;,[240,96,0],{&quot;color&quot;:&quot;cyan&quot;,&quot;offset&quot;:&quot;&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:3},[&quot;Z&quot;]],[&quot;w&quot;,[32,224,192,224]],[&quot;w&quot;,[96,48,192,48]],[&quot;L&quot;,[256,96,3],{&quot;label&quot;:&quot;Z&quot;,&quot;_json_&quot;:6},[&quot;Z&quot;]],[&quot;r&quot;,[192,48,0],{&quot;name&quot;:&quot;Rpullup&quot;,&quot;r&quot;:&quot;10K&quot;,&quot;_json_&quot;:7},[&quot;1&quot;,&quot;Z&quot;]],[&quot;w&quot;,[32,144,32,192]],[&quot;w&quot;,[32,224,32,192]],[&quot;w&quot;,[48,192,32,192]],[&quot;w&quot;,[32,96,32,144]],[&quot;w&quot;,[48,144,32,144]],[&quot;w&quot;,[32,48,32,96]],[&quot;w&quot;,[48,96,32,96]],[&quot;w&quot;,[32,48,48,48]],[&quot;g&quot;,[32,224,0],{&quot;_json_&quot;:16},[&quot;0&quot;]],[&quot;v&quot;,[96,192,1],{&quot;name&quot;:&quot;VC&quot;,&quot;value&quot;:&quot;square(3,0,250K)&quot;,&quot;_json_&quot;:17},[&quot;C&quot;,&quot;0&quot;]],[&quot;v&quot;,[96,144,1],{&quot;name&quot;:&quot;VB&quot;,&quot;value&quot;:&quot;square(3,0,500K)&quot;,&quot;_json_&quot;:18},[&quot;B&quot;,&quot;0&quot;]],[&quot;v&quot;,[96,96,1],{&quot;name&quot;:&quot;VA&quot;,&quot;value&quot;:&quot;square(3,0,1000K)&quot;,&quot;_json_&quot;:19},[&quot;A&quot;,&quot;0&quot;]],[&quot;v&quot;,[96,48,1],{&quot;name&quot;:&quot;Vpwr&quot;,&quot;value&quot;:&quot;dc(3)&quot;,&quot;_json_&quot;:20},[&quot;1&quot;,&quot;0&quot;]],[&quot;L&quot;,[96,96,2],{&quot;label&quot;:&quot;A&quot;,&quot;_json_&quot;:21},[&quot;A&quot;]],[&quot;w&quot;,[96,96,104,96]],[&quot;L&quot;,[96,144,2],{&quot;label&quot;:&quot;B&quot;,&quot;_json_&quot;:23},[&quot;B&quot;]],[&quot;w&quot;,[96,144,104,144]],[&quot;L&quot;,[96,192,2],{&quot;label&quot;:&quot;C&quot;,&quot;_json_&quot;:25},[&quot;C&quot;]],[&quot;w&quot;,[96,192,104,192]],[&quot;w&quot;,[192,96,192,112]],[&quot;s&quot;,[112,96,0],{&quot;color&quot;:&quot;red&quot;,&quot;offset&quot;:&quot;15&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:28},[&quot;A&quot;]],[&quot;w&quot;,[104,96,112,96]],[&quot;s&quot;,[112,144,0],{&quot;color&quot;:&quot;green&quot;,&quot;offset&quot;:&quot;10&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:30},[&quot;B&quot;]],[&quot;w&quot;,[104,144,112,144]],[&quot;w&quot;,[128,144,112,144]],[&quot;s&quot;,[112,192,0],{&quot;color&quot;:&quot;blue&quot;,&quot;offset&quot;:&quot;5&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:33},[&quot;C&quot;]],[&quot;w&quot;,[104,192,112,192]],[&quot;w&quot;,[128,192,112,192]],[&quot;view&quot;,0,0,2,&quot;5&quot;,&quot;10&quot;,&quot;10MEG&quot;,null,&quot;100&quot;,&quot;4us&quot;]]"/>
+                <schematic height="500" width="600" parts="g,n,s" analyses="dc,tran"
+                    submit_analyses="{&quot;tran&quot;:[[&quot;Z&quot;,0.0000004,0.0000009,0.0000014,0.0000019,0.0000024,0.0000029,0.0000034,0.000039]]}" 
+                    initial_value="[[&quot;w&quot;,[112,96,128,96]],[&quot;w&quot;,[256,96,240,96]],[&quot;w&quot;,[192,96,240,96]],[&quot;s&quot;,[240,96,0],{&quot;color&quot;:&quot;cyan&quot;,&quot;offset&quot;:&quot;&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:3},[&quot;Z&quot;]],[&quot;w&quot;,[32,224,192,224]],[&quot;w&quot;,[96,48,192,48]],[&quot;L&quot;,[256,96,3],{&quot;label&quot;:&quot;Z&quot;,&quot;_json_&quot;:6},[&quot;Z&quot;]],[&quot;r&quot;,[192,48,0],{&quot;name&quot;:&quot;Rpullup&quot;,&quot;r&quot;:&quot;10K&quot;,&quot;_json_&quot;:7},[&quot;1&quot;,&quot;Z&quot;]],[&quot;w&quot;,[32,144,32,192]],[&quot;w&quot;,[32,224,32,192]],[&quot;w&quot;,[48,192,32,192]],[&quot;w&quot;,[32,96,32,144]],[&quot;w&quot;,[48,144,32,144]],[&quot;w&quot;,[32,48,32,96]],[&quot;w&quot;,[48,96,32,96]],[&quot;w&quot;,[32,48,48,48]],[&quot;g&quot;,[32,224,0],{&quot;_json_&quot;:16},[&quot;0&quot;]],[&quot;v&quot;,[96,192,1],{&quot;name&quot;:&quot;VC&quot;,&quot;value&quot;:&quot;square(3,0,250K)&quot;,&quot;_json_&quot;:17},[&quot;C&quot;,&quot;0&quot;]],[&quot;v&quot;,[96,144,1],{&quot;name&quot;:&quot;VB&quot;,&quot;value&quot;:&quot;square(3,0,500K)&quot;,&quot;_json_&quot;:18},[&quot;B&quot;,&quot;0&quot;]],[&quot;v&quot;,[96,96,1],{&quot;name&quot;:&quot;VA&quot;,&quot;value&quot;:&quot;square(3,0,1000K)&quot;,&quot;_json_&quot;:19},[&quot;A&quot;,&quot;0&quot;]],[&quot;v&quot;,[96,48,1],{&quot;name&quot;:&quot;Vpwr&quot;,&quot;value&quot;:&quot;dc(3)&quot;,&quot;_json_&quot;:20},[&quot;1&quot;,&quot;0&quot;]],[&quot;L&quot;,[96,96,2],{&quot;label&quot;:&quot;A&quot;,&quot;_json_&quot;:21},[&quot;A&quot;]],[&quot;w&quot;,[96,96,104,96]],[&quot;L&quot;,[96,144,2],{&quot;label&quot;:&quot;B&quot;,&quot;_json_&quot;:23},[&quot;B&quot;]],[&quot;w&quot;,[96,144,104,144]],[&quot;L&quot;,[96,192,2],{&quot;label&quot;:&quot;C&quot;,&quot;_json_&quot;:25},[&quot;C&quot;]],[&quot;w&quot;,[96,192,104,192]],[&quot;w&quot;,[192,96,192,112]],[&quot;s&quot;,[112,96,0],{&quot;color&quot;:&quot;red&quot;,&quot;offset&quot;:&quot;15&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:28},[&quot;A&quot;]],[&quot;w&quot;,[104,96,112,96]],[&quot;s&quot;,[112,144,0],{&quot;color&quot;:&quot;green&quot;,&quot;offset&quot;:&quot;10&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:30},[&quot;B&quot;]],[&quot;w&quot;,[104,144,112,144]],[&quot;w&quot;,[128,144,112,144]],[&quot;s&quot;,[112,192,0],{&quot;color&quot;:&quot;blue&quot;,&quot;offset&quot;:&quot;5&quot;,&quot;plot offset&quot;:&quot;0&quot;,&quot;_json_&quot;:33},[&quot;C&quot;]],[&quot;w&quot;,[104,192,112,192]],[&quot;w&quot;,[128,192,112,192]],[&quot;view&quot;,0,0,2,&quot;5&quot;,&quot;10&quot;,&quot;10MEG&quot;,null,&quot;100&quot;,&quot;4us&quot;]]"
+                    />
             </center>
             <answer type="loncapa/python">
 # for a schematic response, submission[i] is the json representation
@@ -44,6 +47,51 @@ correct = ['correct' if okay else 'incorrect']
 
       </problem>
 
+
+
+<problem url_name="cfn_problem">
+  <text>
+    <script type="text/python" system_path="python_lib">
+def test_csv(expect, ans):
+   # Take out all spaces in expected answer
+   expect = [i.strip(' ') for i in str(expect).split(',')]
+   # Take out all spaces in student solution
+   ans = [i.strip(' ') for i in str(ans).split(',')]
+
+   def strip_q(x):
+      # Strip quotes around strings if students have entered them
+      stripped_ans = []
+      for item in x:
+         if item[0] == "'" and item[-1]=="'":
+            item = item.strip("'")
+         elif item[0] == '"' and item[-1] == '"':
+            item = item.strip('"')
+         stripped_ans.append(item)
+      return stripped_ans
+
+   return strip_q(expect) == strip_q(ans)
+</script>
+    <ol class="enumerate">
+      <li>
+        <pre>
+num = 0
+while num &lt;= 5:
+    print(num)
+    num += 1
+
+print("Outside of loop")
+print(num)
+ </pre>
+        <p>
+          <customresponse cfn="test_csv" expect="0, 1, 2, 3, 4, 5, 'Outside of loop', 6">
+            <textline size="50" correct_answer="0, 1, 2, 3, 4, 5, 'Outside of loop', 6"/>
+          </customresponse>
+        </p>
+      </li>
+    </ol>
+  </text>
+</problem>
+
     </vertical>
   </chapter>
 </course>

lms/djangoapps/courseware/tests/tests.py

@@ -986,7 +986,7 @@ class TestSchematicResponse(TestSubmittingProblems):
         return resp
 
     def test_get_graded(self):
-        resp = self.submit_question_answer('H1P1',
+        resp = self.submit_question_answer('schematic_problem',
             [['transient', {'Z': [
             [0.0000004, 2.8],
             [0.0000009, 2.8],
@@ -1001,8 +1001,8 @@ class TestSchematicResponse(TestSubmittingProblems):
         respdata = json.loads(resp.content)
         self.assertEqual(respdata['success'], 'correct')
 
-        self.reset_question_answer('H1P1')
-        resp = self.submit_question_answer('H1P1',
+        self.reset_question_answer('schematic_problem')
+        resp = self.submit_question_answer('schematic_problem',
             [['transient', {'Z': [
             [0.0000004, 2.8],
             [0.0000009, 0.0],       # wrong.
@@ -1016,3 +1016,31 @@ class TestSchematicResponse(TestSubmittingProblems):
             )
         respdata = json.loads(resp.content)
         self.assertEqual(respdata['success'], 'incorrect')
+
+
+@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
+class TestCustomResponseCfnFunction(TestSubmittingProblems):
+    """Check that cfn functions work properly."""
+
+    course_slug = "embedded_python"
+    course_when = "2013_Spring"
+
+    def submit_question_answer(self, problem_url_name, responses):
+        """Particular to the embedded_python/2013_Spring course."""
+        problem_location = self.problem_location(problem_url_name)
+        modx_url = self.modx_url(problem_location, 'problem_check')
+        resp = self.client.post(modx_url, {
+            'input_i4x-edX-embedded_python-problem-{0}_2_1'.format(problem_url_name): responses,
+            })
+        return resp
+
+    def test_get_graded(self):
+        resp = self.submit_question_answer('cfn_problem', "0, 1, 2, 3, 4, 5, 'Outside of loop', 6")
+        respdata = json.loads(resp.content)
+        self.assertEqual(respdata['success'], 'correct')
+
+        self.reset_question_answer('cfn_problem')
+
+        resp = self.submit_question_answer('cfn_problem', "xyzzy!")
+        respdata = json.loads(resp.content)
+        self.assertEqual(respdata['success'], 'incorrect')