Merge "Add LUKSv1 inspector"

oslo_utils/imageutils/format_inspector.py

@@ -1276,6 +1276,45 @@ class GPTInspector(FileInspector):
             raise SafetyViolation('GPT MBR has no partitions defined')
 
 
+# The LUKSv1 format consists of a header with some metadata and key
+# information followed by a bulk non-sparse data payload which is the
+# encyrpted disk image.
+# https://gitlab.com/cryptsetup/cryptsetup/-/wikis/LUKS-standard/on-disk-format.pdf
+# LUKSv2 is a different but similar spec, which is not yet covered here (or
+# in qemu).
+class LUKSInspector(FileInspector):
+    NAME = 'luks'
+
+    def _initialize(self):
+        self.new_region('header', CaptureRegion(0, 592))
+        self.add_safety_check(SafetyCheck('version', self.check_version))
+
+    @property
+    def format_match(self):
+        return self.region('header').data[:6] == b'LUKS\xBA\xBE'
+
+    @property
+    def header_items(self):
+        fields = struct.unpack('>6sh32s32s32sI',
+                               self.region('header').data[:108])
+        names = ['magic', 'version', 'cipher_alg', 'cipher_mode', 'hash',
+                 'payload_offset']
+        return dict(zip(names, fields))
+
+    def check_version(self):
+        header = self.header_items
+        if header['version'] != 1:
+            raise SafetyViolation(
+                'LUKS version %i is not supported' % header['version'])
+
+    @property
+    def virtual_size(self):
+        # NOTE(danms): This will not be correct until/unless the whole stream
+        # has been read, since all we have is (effectively the size of the
+        # header. This is similar to how RawFileInspector works.
+        return super().virtual_size - self.header_items['payload_offset'] * 512
+
+
 class InspectWrapper:
     """A file-like object that wraps another and detects the format.
 
@@ -1437,6 +1476,7 @@ ALL_FORMATS = {
     'qed': QEDInspector,
     'iso': ISOInspector,
     'gpt': GPTInspector,
+    'luks': LUKSInspector,
 }
 
 

oslo_utils/tests/imageutils/test_format_inspector.py

@@ -127,6 +127,14 @@ class TestFormatInspectors(test_base.BaseTestCase):
         self._created_files.append(fn)
         return fn
 
+    def _create_luks(self, image_size, subformat):
+        fn = tempfile.mktemp(suffix='.luks')
+        cmd = ['qemu-img', 'create', '-f', 'luks',
+               '--object', 'secret,id=sec0,data=secret-passphrase',
+               '-o', 'key-secret=sec0', fn, '%i' % image_size]
+        subprocess.check_output(' '.join(cmd), shell=True)
+        return fn
+
     def _create_img(
             self, fmt, size, subformat=None, options=None,
             backing_file=None):
@@ -143,6 +151,8 @@ class TestFormatInspectors(test_base.BaseTestCase):
             return self._create_iso(size, subformat)
         if fmt == 'gpt':
             return self._create_gpt(size, subformat)
+        if fmt == 'luks':
+            return self._create_luks(size, subformat)
 
         if fmt == 'vhd':
             # QEMU calls the vhd format vpc
@@ -216,11 +226,22 @@ class TestFormatInspectors(test_base.BaseTestCase):
     def _test_format_at_block_size(self, format_name, img, block_size):
         wrapper = format_inspector.InspectWrapper(open(img, 'rb'),
                                                   format_name)
-
+        current_block_size = block_size
         while True:
-            chunk = wrapper.read(block_size)
+            chunk = wrapper.read(current_block_size)
             if not chunk:
                 break
+            # If we've already settled on a format, the block size no longer
+            # really matters for correctness since we won't be capturing and
+            # parsing anything else. Bump up the block size so we will eat
+            # the rest of the file more efficiently. This matters for formats
+            # that are non-sparse and for which the virtual_size calculation
+            # relies on the actual size of the file (i.e. raw, gpt, luks, etc)
+            try:
+                if current_block_size == block_size and wrapper.format:
+                    current_block_size = 64 * units.Ki
+            except Exception:
+                pass
 
         wrapper.close()
         self.assertIsNotNone(wrapper.format, 'Failed to detect format')
@@ -279,7 +300,7 @@ class TestFormatInspectors(test_base.BaseTestCase):
                                             subformat=subformat,
                                             safety_check=True)
 
-    @ddt.data('qcow2', 'vhd', 'vhdx', 'vmdk', 'gpt')
+    @ddt.data('qcow2', 'vhd', 'vhdx', 'vmdk', 'gpt', 'luks')
     def test_format(self, format):
         self._test_format(format)