Python: Adjust PamAuthorization examples

They did not have proper formatting (only 2 spaces), and I restructured
them a bit more so they look like code in the wild

python/ql/src/experimental/Security/CWE-285/PamAuthorizationBad.py

@@ -1,13 +1,19 @@
-def authenticate(self, username, password, service='login', encoding='utf-8', resetcreds=True):
-  libpam                    = CDLL(find_library("pam"))
-  pam_authenticate          = libpam.pam_authenticate
-  pam_authenticate.restype  = c_int
-  pam_authenticate.argtypes = [PamHandle, c_int]
+libpam                    = CDLL(find_library("pam"))
 
-  
-  handle = PamHandle()
-  conv   = PamConv(my_conv, 0)
-  retval = pam_start(service, username, byref(conv), byref(handle))
+pam_authenticate          = libpam.pam_authenticate
+pam_authenticate.restype  = c_int
+pam_authenticate.argtypes = [PamHandle, c_int]
 
-  retval = pam_authenticate(handle, 0)  
-  return retval == 0
+def authenticate(username, password, service='login'):
+    def my_conv(n_messages, messages, p_response, app_data):
+        """
+        Simple conversation function that responds to any prompt where the echo is off with the supplied password
+        """
+        ...
+
+    handle = PamHandle()
+    conv   = PamConv(my_conv, 0)
+    retval = pam_start(service, username, byref(conv), byref(handle))
+
+    retval = pam_authenticate(handle, 0)
+    return retval == 0

python/ql/src/experimental/Security/CWE-285/PamAuthorizationGood.py

@@ -1,17 +1,25 @@
-def authenticate(self, username, password, service='login', encoding='utf-8', resetcreds=True):
-  libpam                    = CDLL(find_library("pam"))
-  pam_authenticate          = libpam.pam_authenticate
-  pam_acct_mgmt          = libpam.pam_acct_mgmt
-  pam_authenticate.restype  = c_int
-  pam_authenticate.argtypes = [PamHandle, c_int]
-  pam_acct_mgmt.restype  = c_int
-  pam_acct_mgmt.argtypes = [PamHandle, c_int]
-  
-  handle = PamHandle()
-  conv   = PamConv(my_conv, 0)
-  retval = pam_start(service, username, byref(conv), byref(handle))
+libpam                    = CDLL(find_library("pam"))
 
-  retval = pam_authenticate(handle, 0)
-  if retval == 0:
-      retval = pam_acct_mgmt(handle, 0)
-  return retval == 0
+pam_authenticate          = libpam.pam_authenticate
+pam_authenticate.restype  = c_int
+pam_authenticate.argtypes = [PamHandle, c_int]
+
+pam_acct_mgmt          = libpam.pam_acct_mgmt
+pam_acct_mgmt.restype  = c_int
+pam_acct_mgmt.argtypes = [PamHandle, c_int]
+
+def authenticate(username, password, service='login'):
+    def my_conv(n_messages, messages, p_response, app_data):
+        """
+        Simple conversation function that responds to any prompt where the echo is off with the supplied password
+        """
+        ...
+
+    handle = PamHandle()
+    conv   = PamConv(my_conv, 0)
+    retval = pam_start(service, username, byref(conv), byref(handle))
+
+    retval = pam_authenticate(handle, 0)
+    if retval == 0:
+        retval = pam_acct_mgmt(handle, 0)
+    return retval == 0