pytest/sddl: environment option for exporting as fuzz seeds

We want realistic examples for sddl fuzzing seeds, and we want
realistic examples for sddl tests, so hopefully we only need to get
it right once.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

python/samba/tests/sddl.py

@@ -20,6 +20,7 @@
 from samba.dcerpc import security
 from samba.tests import TestCase, DynamicTestCase, get_env_dir
 from samba.colour import c_RED, c_GREEN
+import os
 
 
 class SddlDecodeEncodeBase(TestCase):
@@ -32,7 +33,9 @@ class SddlDecodeEncodeBase(TestCase):
                 ("SAMBA_WRITE_WINDOWS_STRINGS_DIR",
                  cls.write_windows_strings),
                 ("SAMBA_READ_WINDOWS_STRINGS_DIR",
-                 cls.read_windows_strings)]:
+                 cls.read_windows_strings),
+                ("SAMBA_WRITE_FUZZ_STRINGS_DIR",
+                 cls.write_sddl_strings_for_fuzz_seeds)]:
             dir = get_env_dir(key)
             if dir is not None:
                 fn(dir)
@@ -77,6 +80,24 @@ class SddlDecodeEncodeBase(TestCase):
             sd = security.descriptor.from_sddl(s, self.domain_sid)
             print(sd.as_sddl(self.domain_sid))
 
+    @classmethod
+    def write_sddl_strings_for_fuzz_seeds(cls, dir):
+        """write all the SDDL strings we have into a directory as individual
+        files, using a naming convention beloved of fuzzing engines.
+
+        To run this set an environment variable; see
+        cls.setUpDynamicTestCases(), above.
+
+        Note this will only run in subclasses annotated with @DynamicTestCase.
+        """
+        from hashlib import md5
+        for sddl in cls.strings:
+            if not isinstance(sddl, str):
+                sddl = sddl[0]
+            name = md5(sddl.encode()).hexdigest()
+            with open(os.path.join(dir, name), 'w') as f:
+                f.write(sddl)
+
     @classmethod
     def write_windows_strings(cls, dir):
         """Write all test cases in the format used by