Fix interpreter loader (#115)

* Correctly compute total interp size

* Rename

* Make staticmethod

* Add basic loading test

manticore/models/linux.py

@@ -731,11 +731,7 @@ class Linux(object):
 
                 if base == 0 and interpreter.header.e_type == 'ET_DYN':
                     assert vaddr == 0
-                    total_size = 0
+                    total_size = self._interp_total_size(interpreter)
-                    for _elf_segment in interpreter.iter_segments():
-                        if _elf_segment.header.p_type == 'PT_LOAD':
-                            _memsz = elf_segment.header.p_memsz + (_elf_segment.header.p_vaddr & (align-1))
-                            total_size += cpu.memory._ceil(_memsz)
                     base = stack_base - total_size 
 
                 if base == 0:
@@ -1766,6 +1762,20 @@ class Linux(object):
             for reg, val in x86_defaults.iteritems():
                 cpu.regfile.write(reg, val)
 
+    @staticmethod
+    def _interp_total_size(interp):
+        '''
+        Compute total load size of interpreter.
+
+        :param ELFFile interp: interpreter ELF .so
+        :return: total load size of interpreter, not aligned
+        :rtype: int
+        '''
+        load_segs = filter(lambda x: x.header.p_type == 'PT_LOAD', interp.iter_segments())
+        last = load_segs[-1]
+        return last.header.p_vaddr + last.header.p_memsz
+
+
 ############################################################################
 # Symbolic versions follows
 

tests/test_linux.py

@@ -4,6 +4,9 @@ from manticore.models import linux
 
 
 class LinuxTest(unittest.TestCase):
+    '''
+    TODO(mark): these tests assumes /bin/ls is a dynamic x64 binary
+    '''
     BIN_PATH = '/bin/ls'
 
     def setUp(self):
@@ -22,9 +25,6 @@ class LinuxTest(unittest.TestCase):
             self.assertEqual(cpu.regfile.read(reg), val)
 
     def test_stack_init(self):
-        '''
-        TODO(mark): this test assumes /bin/ls is a x64 binary
-        '''
         argv = ['arg1', 'arg2', 'arg3']
         real_argv = [self.BIN_PATH] + argv
         envp = ['env1', 'env2', 'env3']
@@ -41,3 +41,19 @@ class LinuxTest(unittest.TestCase):
 
         for i, env in enumerate(envp):
             self.assertEqual(self.linux._read_string(cpu, cpu.read_int(envp_ptr + i*8)), env)
+
+    def test_load_maps(self):
+        mappings = self.linux.current.memory.mappings()
+
+        # stack should be last
+        last_map = mappings[-1]
+        last_map_perms = last_map[2]
+        self.assertEqual(last_map_perms, 'rwx')
+
+        # binary should be first two
+        first_map, second_map = mappings[:2]
+        first_map_name = first_map[4]
+        second_map_name = second_map[4]
+        self.assertEqual(first_map_name, '/bin/ls')
+        self.assertEqual(second_map_name, '/bin/ls')
+