safe_crypt() now handles "*0" and similar error returns from crypt()

2 files changed, 31 insertions, 12 deletions

diff --git a/passlib/tests/test_utils.py b/passlib/tests/test_utils.py
index 9d641e1..734479b 100644
--- a/passlib/tests/test_utils.py
+++ b/passlib/tests/test_utils.py
@@ -139,15 +139,19 @@ class MiscTest(TestCase):
         self.assertTrue(test_crypt("test", h1))
         self.assertFalse(test_crypt("test", h1x))
 
-        # test crypt.crypt() returning None is supported.
-        # (Python's Modules/_cryptmodule.c notes some platforms may do this
-        # when algorithm is not supported - but don't say which platforms)
+        # check crypt returning variant error indicators
+        # some platforms return None on errors, others empty string,
+        # The BSDs in some cases return ":"
         import passlib.utils as mod
         orig = mod._crypt
         try:
-            mod._crypt = lambda secret, hash: None
-            self.assertEqual(safe_crypt("test", "aa"), None)
-            self.assertFalse(test_crypt("test", h1))
+            fake = None
+            mod._crypt = lambda secret, hash: fake
+            for fake in [None, "", ":", ":0", "*0"]:
+                self.assertEqual(safe_crypt("test", "aa"), None)
+                self.assertFalse(test_crypt("test", h1))
+            fake = 'xxx'
+            self.assertEqual(safe_crypt("test", "aa"), "xxx")
         finally:
             mod._crypt = orig
 
diff --git a/passlib/utils/__init__.py b/passlib/utils/__init__.py
index 3edfaca..323b98f 100644
--- a/passlib/utils/__init__.py
+++ b/passlib/utils/__init__.py
@@ -1256,6 +1256,14 @@ except ImportError: #pragma: no cover
 else:
     has_crypt = True
     _NULL = '\x00'
+
+    # some crypt() variants will return various constant strings when
+    # an invalid/unrecognized config string is passed in; instead of
+    # returning NULL / None. examples include ":", ":0", "*0", etc.
+    # safe_crypt() returns None for any string starting with one of the
+    # chars in this string...
+    _invalid_prefixes = u("*:!")
+
     if PY3:
         def safe_crypt(secret, hash):
             if isinstance(secret, bytes):
@@ -1281,8 +1289,10 @@ else:
                 raise ValueError("null character in secret")
             if isinstance(hash, bytes):
                 hash = hash.decode("ascii")
-            # NOTE: may return None on some OSes, if hash not supported.
-            return _crypt(secret, hash)
+            result = _crypt(secret, hash)
+            if not result or result[0] in _invalid_prefixes:
+                return None
+            return result
     else:
         def safe_crypt(secret, hash):
             if isinstance(secret, unicode):
@@ -1291,12 +1301,13 @@ else:
                 raise ValueError("null character in secret")
             if isinstance(hash, unicode):
                 hash = hash.encode("ascii")
-            # NOTE: may return None on some OSes, if hash not supported.
             result = _crypt(secret, hash)
-            if result is None:
+            if not result:
                 return None
-            else:
-                return result.decode("ascii")
+            result = result.decode("ascii")
+            if result[0] in _invalid_prefixes:
+                return None
+            return result
 
 _add_doc(safe_crypt, """wrapper around stdlib's crypt.
 
@@ -1322,6 +1333,10 @@ _add_doc(safe_crypt, """wrapper around stdlib's crypt.
         * Some OSes will return ``None`` if they don't recognize
           the algorithm being used (though most will simply fall
           back to des-crypt).
+
+        * Some OSes will return an error string if the input config
+          is recognized but malformed; current code converts these to ``None``
+          as well.
     """)
 
 def test_crypt(secret, hash):