passlib.context: now raises UnknownHashError() if hash can't be identified.

this inherits from ValueError, and has same text, so backwards compatible.

5 files changed, 36 insertions, 27 deletions

diff --git a/docs/history/1.7.rst b/docs/history/1.7.rst
index 6d6293b..42ffeec 100644
--- a/docs/history/1.7.rst
+++ b/docs/history/1.7.rst
@@ -12,6 +12,18 @@ Passlib 1.7
     and will require Python >= 3.5.  The 1.7 series will be the last
     to support Python 2.7.  (See :issue:`119` for rationale).
 
+**1.7.4** (NOT YET RELEASED)
+============================
+
+Other Changes
+-------------
+* .. py:currentmodule:: passlib.context
+
+  :class:`CryptContext` will now throw :exc:`~passlib.exc.UnknownHashError` when it can't identify
+  a hash provided to methods such as :meth:`!CryptContext.verify`.
+  Previously it would throw a generic :exc:`ValueError`.
+
+
 **1.7.3** (2020-10-06)
 ======================
 
diff --git a/passlib/context.py b/passlib/context.py
index 2822d70..bc3cbf5 100644
--- a/passlib/context.py
+++ b/passlib/context.py
@@ -11,6 +11,7 @@ import time
 from warnings import warn
 # site
 # pkg
+from passlib import exc
 from passlib.exc import ExpectedStringError, ExpectedTypeError, PasslibConfigWarning
 from passlib.registry import get_crypt_handler, _validate_handler_name
 from passlib.utils import (handlers as uh, to_bytes,
@@ -1128,7 +1129,7 @@ class _CryptConfig(object):
         elif not self.schemes:
             raise KeyError("no crypt algorithms supported")
         else:
-            raise ValueError("hash could not be identified")
+            raise exc.UnknownHashError("hash could not be identified")
 
     @memoized_property
     def disabled_record(self):
diff --git a/passlib/crypto/digest.py b/passlib/crypto/digest.py
index 0a9b77a..8da9b5e 100644
--- a/passlib/crypto/digest.py
+++ b/passlib/crypto/digest.py
@@ -469,7 +469,7 @@ class HashInfo(SequenceMixin):
             helper that installs stub constructor which throws specified error <msg>.
             """
             def const(source=b""):
-                raise exc.UnknownHashError(name, message=msg)
+                raise exc.UnknownHashError(msg, name)
             if required:
                 # if caller only wants supported digests returned,
                 # just throw error immediately...
diff --git a/passlib/exc.py b/passlib/exc.py
index 4539c7d..755c7dc 100644
--- a/passlib/exc.py
+++ b/passlib/exc.py
@@ -193,17 +193,23 @@ class UnknownHashError(ValueError):
     As of version 1.7.3, this may also be raised if hash algorithm is known,
     but has been disabled due to FIPS mode (message will include phrase "disabled for fips").
 
+    As of version 1.7.4, this may be raised if a :class:`~passlib.context.CryptContext`
+    is unable to identify the algorithm used by a password hash.
+
     .. versionadded:: 1.7
 
     .. versionchanged: 1.7.3
         added 'message' argument.
+
+    .. versionchanged:: 1.7.4
+        altered call signature.
     """
-    def __init__(self, name, message=None):
-        self.name = name
+    def __init__(self, message=None, value=None):
+        self.value = value
         if message is None:
-            message = "unknown hash algorithm: %r" % name
+            message = "unknown hash algorithm: %r" % value
         self.message = message
-        ValueError.__init__(self, name, message)
+        ValueError.__init__(self, message, value)
 
     def __str__(self):
         return self.message
diff --git a/passlib/tests/test_context.py b/passlib/tests/test_context.py
index ffd37e9..09b52c0 100644
--- a/passlib/tests/test_context.py
+++ b/passlib/tests/test_context.py
@@ -1647,6 +1647,7 @@ sha512_crypt__min_rounds = 45000
         #
         # init ref info
         #
+        from passlib.exc import UnknownHashError
         from passlib.hash import md5_crypt, unix_disabled
 
         ctx = CryptContext(["des_crypt"])
@@ -1684,18 +1685,13 @@ sha512_crypt__min_rounds = 45000
 
         # test w/o disabled hash support
         self.assertTrue(ctx.is_enabled(h_ref))
-        HASH_NOT_IDENTIFIED = "hash could not be identified"
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.is_enabled, h_other)
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.is_enabled, h_dis)
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.is_enabled, h_dis_ref)
+        self.assertRaises(UnknownHashError, ctx.is_enabled, h_other)
+        self.assertRaises(UnknownHashError, ctx.is_enabled, h_dis)
+        self.assertRaises(UnknownHashError, ctx.is_enabled, h_dis_ref)
 
         # test w/ disabled hash support
         self.assertTrue(ctx2.is_enabled(h_ref))
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.is_enabled, h_other)
+        self.assertRaises(UnknownHashError, ctx.is_enabled, h_other)
         self.assertFalse(ctx2.is_enabled(h_dis))
         self.assertFalse(ctx2.is_enabled(h_dis_ref))
 
@@ -1704,24 +1700,18 @@ sha512_crypt__min_rounds = 45000
         #
 
         # test w/o disabled hash support
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.enable, "")
+        self.assertRaises(UnknownHashError, ctx.enable, "")
         self.assertRaises(TypeError, ctx.enable, None)
         self.assertEqual(ctx.enable(h_ref), h_ref)
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.enable, h_other)
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.enable, h_dis)
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.enable, h_dis_ref)
+        self.assertRaises(UnknownHashError, ctx.enable, h_other)
+        self.assertRaises(UnknownHashError, ctx.enable, h_dis)
+        self.assertRaises(UnknownHashError, ctx.enable, h_dis_ref)
 
         # test w/ disabled hash support
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx.enable, "")
+        self.assertRaises(UnknownHashError, ctx.enable, "")
         self.assertRaises(TypeError, ctx2.enable, None)
         self.assertEqual(ctx2.enable(h_ref), h_ref)
-        self.assertRaisesRegex(ValueError, HASH_NOT_IDENTIFIED,
-                               ctx2.enable, h_other)
+        self.assertRaises(UnknownHashError, ctx2.enable, h_other)
         self.assertRaisesRegex(ValueError, "cannot restore original hash",
                                ctx2.enable, h_dis)
         self.assertEqual(ctx2.enable(h_dis_ref), h_ref)