Commit f1255a3c authored by Aymeric Augustin's avatar Aymeric Augustin
Browse files

Fixed #18144 -- Restored compatibility with SHA1 hashes with empty salt. 

Thanks dahool for the report and initial version of the patch.
parent 509798ae

django/conf/global_settings.py

+1 −0
Original line number Diff line number Diff line
@@ -510,6 +510,7 @@ PASSWORD_HASHERS = ( 
    'django.contrib.auth.hashers.BCryptPasswordHasher',

    'django.contrib.auth.hashers.SHA1PasswordHasher',

    'django.contrib.auth.hashers.MD5PasswordHasher',

    'django.contrib.auth.hashers.UnsaltedSHA1PasswordHasher',

    'django.contrib.auth.hashers.UnsaltedMD5PasswordHasher',

    'django.contrib.auth.hashers.CryptPasswordHasher',

)

django/contrib/auth/hashers.py

+46 −6
Original line number Diff line number Diff line
@@ -127,9 +127,14 @@ def identify_hasher(encoded): 
    get_hasher() to return hasher. Raises ValueError if

    algorithm cannot be identified, or if hasher is not loaded.

    """

    # Ancient versions of Django created plain MD5 passwords and accepted

    # MD5 passwords with an empty salt.

    if ((len(encoded) == 32 and '$' not in encoded) or

            (len(encoded) == 37 and encoded.startswith('md5$$'))):

        algorithm = 'unsalted_md5'

    # Ancient versions of Django accepted SHA1 passwords with an empty salt.

    elif len(encoded) == 46 and encoded.startswith('sha1$$'):

        algorithm = 'unsalted_sha1'

    else:

        algorithm = encoded.split('$', 1)[0]

    return get_hasher(algorithm)
@@ -350,14 +355,48 @@ class MD5PasswordHasher(BasePasswordHasher): 
        ])





class UnsaltedSHA1PasswordHasher(BasePasswordHasher):

    """

    Very insecure algorithm that you should *never* use; stores SHA1 hashes

    with an empty salt.



    This class is implemented because Django used to accept such password

    hashes. Some older Django installs still have these values lingering

    around so we need to handle and upgrade them properly.

    """

    algorithm = "unsalted_sha1"



    def salt(self):

        return ''



    def encode(self, password, salt):

        assert salt == ''

        hash = hashlib.sha1(force_bytes(password)).hexdigest()

        return 'sha1$$%s' % hash



    def verify(self, password, encoded):

        encoded_2 = self.encode(password, '')

        return constant_time_compare(encoded, encoded_2)



    def safe_summary(self, encoded):

        assert encoded.startswith('sha1$$')

        hash = encoded[6:]

        return SortedDict([

            (_('algorithm'), self.algorithm),

            (_('hash'), mask_hash(hash)),

        ])





class UnsaltedMD5PasswordHasher(BasePasswordHasher):

    """

    I am an incredibly insecure algorithm you should *never* use;

    stores unsalted MD5 hashes without the algorithm prefix.

    Incredibly insecure algorithm that you should *never* use; stores unsalted

    MD5 hashes without the algorithm prefix, also accepts MD5 hashes with an

    empty salt.



    This class is implemented because Django used to store passwords

    this way. Some older Django installs still have these values

    lingering around so we need to handle and upgrade them properly.

    This class is implemented because Django used to store passwords this way

    and to accept such password hashes. Some older Django installs still have

    these values lingering around so we need to handle and upgrade them

    properly.

    """

    algorithm = "unsalted_md5"
@@ -365,6 +404,7 @@ class UnsaltedMD5PasswordHasher(BasePasswordHasher): 
        return ''



    def encode(self, password, salt):

        assert salt == ''

        return hashlib.md5(force_bytes(password)).hexdigest()



    def verify(self, password, encoded):

django/contrib/auth/tests/hashers.py

+14 −3
Original line number Diff line number Diff line
@@ -60,7 +60,7 @@ class TestUtilsHashPass(unittest.TestCase): 
        self.assertEqual(identify_hasher(encoded).algorithm, "md5")



    def test_unsalted_md5(self):

        encoded = make_password('lètmein', 'seasalt', 'unsalted_md5')

        encoded = make_password('lètmein', '', 'unsalted_md5')

        self.assertEqual(encoded, '88a434c88cca4e900f7874cd98123f43')

        self.assertTrue(is_password_usable(encoded))

        self.assertTrue(check_password('lètmein', encoded))
@@ -72,6 +72,17 @@ class TestUtilsHashPass(unittest.TestCase): 
        self.assertTrue(check_password('lètmein', alt_encoded))

        self.assertFalse(check_password('lètmeinz', alt_encoded))



    def test_unsalted_sha1(self):

        encoded = make_password('lètmein', '', 'unsalted_sha1')

        self.assertEqual(encoded, 'sha1$$6d138ca3ae545631b3abd71a4f076ce759c5700b')

        self.assertTrue(is_password_usable(encoded))

        self.assertTrue(check_password('lètmein', encoded))

        self.assertFalse(check_password('lètmeinz', encoded))

        self.assertEqual(identify_hasher(encoded).algorithm, "unsalted_sha1")

        # Raw SHA1 isn't acceptable

        alt_encoded = encoded[6:]

        self.assertFalse(check_password('lètmein', alt_encoded))



    @skipUnless(crypt, "no crypt module to generate password.")

    def test_crypt(self):

        encoded = make_password('lètmei', 'ab', 'crypt')