Merge pull request #350 from desultory/dev

Add basic dm-integrity support

Author: desultory

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "ugrd"
-version = "2.0.2"
+version = "2.1.0"
 authors = [
   { name="Desultory", email="[email protected]" },
 ]
@@ -19,7 +19,7 @@ classifiers = [
 
 dependencies = [
     "zenlib >= 3.0.2",
-    "pycpio >= 1.5.2"
+    "pycpio >= 1.5.5"
 ]
 
 [project.optional-dependencies]

src/ugrd/crypto/cryptsetup.py

@@ -1,5 +1,5 @@
 __author__ = "desultory"
-__version__ = "4.1.3"
+__version__ = "4.2.0"
 
 from json import loads
 from pathlib import Path
@@ -28,6 +28,7 @@
     "include_header",
     "validate_key",
     "validate_header",
+    "_dm-integrity",  # Internal parameter for when dm-integrity was detected. mostly used for test automation
 ]
 
 
@@ -147,6 +148,9 @@ def _get_dm_info(self, mapped_name: str) -> dict:
 def _get_dm_slave_info(self, device_info: dict) -> (str, dict):
     """Gets the device mapper slave information for a particular device."""
     slave_source = device_info["slaves"][0]
+    # For integrity backed devices, get the slave's slave
+    if self["_vblk_info"].get(slave_source, {}).get("uuid", "").startswith("CRYPT-SUBDEV"):
+        slave_source = self["_vblk_info"][slave_source]["slaves"][0]
     slave_name = self["_vblk_info"].get(slave_source, {}).get("name")
     search_paths = ["/dev/", "/dev/mapper/"]
 
@@ -207,7 +211,7 @@ def _detect_luks_aes_module(self, luks_cipher_name: str) -> None:
         self["_kmod_auto"] = crypto_config["module"]
 
 
-def _detect_luks_header_aes(self, luks_info: dict) -> dict:
+def _detect_luks_header_aes(self, luks_info: dict) -> None:
     """Checks the cipher type in the LUKS header, reads /proc/crypto to find the
     corresponding driver. If it's not builtin, adds the module to the kernel modules."""
     for keyslot in luks_info.get("keyslots", {}).values():
@@ -218,7 +222,7 @@ def _detect_luks_header_aes(self, luks_info: dict) -> dict:
             _detect_luks_aes_module(self, segment["encryption"])
 
 
-def _detect_luks_header_sha(self, luks_info: dict) -> dict:
+def _detect_luks_header_sha(self, luks_info: dict) -> None:
     """Reads the hash algorithm from the LUKS header,
     enables the corresponding kernel module using _crypto_ciphers"""
     for keyslot in luks_info.get("keyslots", {}).values():
@@ -229,6 +233,21 @@ def _detect_luks_header_sha(self, luks_info: dict) -> dict:
             self["kernel_modules"] = self._crypto_ciphers[digest["hash"]]["driver"]
 
 
+def _detect_luks_header_integrity(self, luks_info: dict, mapped_name: str) -> None:
+    """Reads the integrity algorithm from the LUKS header,
+    Enables the dm-integrity module, and returns the integrity type."""
+    for segment in luks_info.get("segments", {}).values():
+        if integrity_type := segment.get("integrity", {}).get("type"):
+            integrity_kmods = ["dm_integrity", "authenc"]
+            if integrity_type.startswith("hmac"):
+                integrity_kmods.append("hmac")
+            self.logger.info(
+                f"[{c_(mapped_name, 'blue')}]({c_(integrity_type, 'cyan')}) Enabling kernel modules for dm-integrity: {c_(', '.join(integrity_kmods), 'magenta', bright=True)}"
+            )
+            self["cryptsetup"][mapped_name]["_dm-integrity"] = integrity_type
+            return
+
+
 @contains("cryptsetup_header_validation", "Skipping cryptsetup header validation.", log_level=30)
 def _validate_cryptsetup_header(self, mapped_name: str) -> None:
     """Validates configured cryptsetup volumes against the LUKS header."""
@@ -265,6 +284,7 @@ def _validate_cryptsetup_header(self, mapped_name: str) -> None:
 
     _detect_luks_header_aes(self, luks_info)
     _detect_luks_header_sha(self, luks_info)
+    _detect_luks_header_integrity(self, luks_info, mapped_name)
 
     if not self["argon2"]:  # if argon support was not detected, check if the header wants it
         for keyslot in luks_info.get("keyslots", {}).values():

src/ugrd/fs/mounts.py

@@ -1,5 +1,5 @@
 __author__ = "desultory"
-__version__ = "7.1.4"
+__version__ = "7.2.1"
 
 from pathlib import Path
 from re import search
@@ -504,20 +504,26 @@ def _autodetect_dm(self, mountpoint, device=None) -> None:
     Ensures it's a device mapper mount, then autodetects the mount type.
     Adds kmods to the autodetect list based on the mount source.
     """
+    # If a device is explicity passed, set it as the source device
     if device:
         self.logger.debug("[%s] Using provided device for mount autodetection: %s" % (mountpoint, device))
         source_device = device
+    # If it's a mountpoint, try to resolve underlying devices
     elif mountpoint:
         source_device = _resolve_overlay_lower_device(self, mountpoint)
     else:
         raise AutodetectError("Mountpoint not found in host mounts: %s" % mountpoint)
 
+    # Get the name of the device from the path
     device_name = source_device.split("/")[-1]
+    # Check that it's a device mapper mount (by prefix or path)
+    # If it's not, skip this autodetection by returning early
     if not any(device_name.startswith(prefix) for prefix in ["dm-", "md"]):
         if not source_device.startswith("/dev/mapper/"):
             self.logger.debug("Mount is not a device mapper mount: %s" % source_device)
             return
 
+    # Get the source device using blkid info/virtual block device info
     if source_device not in self["_blkid_info"]:
         if device_name in self["_vblk_info"]:
             source_name = self["_vblk_info"][device_name]["name"]
@@ -535,6 +541,7 @@ def _autodetect_dm(self, mountpoint, device=None) -> None:
     major, minor = _get_device_id(source_device)
     self.logger.debug("[%s] Major: %s, Minor: %s" % (source_device, major, minor))
 
+    # Get the virtual block device name using the major/minor
     for name, info in self["_vblk_info"].items():
         if info["major"] == str(major) and info["minor"] == str(minor):
             dev_name = name
@@ -544,27 +551,43 @@ def _autodetect_dm(self, mountpoint, device=None) -> None:
             "[%s] Unable to find device mapper device with maj: %s min: %s" % (source_device, major, minor)
         )
 
+    # Check that the virtual block device has slaves defined
     if len(self["_vblk_info"][dev_name]["slaves"]) == 0:
         raise AutodetectError("No slaves found for device mapper device, unknown type: %s" % source_device.name)
+    # Treat the first slave as the source for autodetection
     slave_source = self["_vblk_info"][dev_name]["slaves"][0]
+    # If the slave source is a CRYPT-SUBDEV device, use its slave instead
+    if self["_vblk_info"].get(slave_source, {}).get("uuid", "").startswith("CRYPT-SUBDEV"):
+        slave_source = self["_vblk_info"][slave_source]["slaves"][0]
+        self.logger.info(f"[{c_(dev_name, 'blue')}] Slave is a CRYPT-SUBDEV, using its slave instead: {c_(slave_source, 'cyan')}")
+        # Add the kmod for it
+        self.logger.info(f"[{c_(dev_name, 'blue')}] Adding kmod for CRYPT-SUBDEV: {c_('dm-crypt', 'magenta')}")
+        self["_kmod_auto"] = ["dm_integrity", "authenc"]
+
     autodetect_mount_kmods(self, slave_source)
 
+    # Check that the source device name matches the devie mapper name
+    if source_device.name != self["_vblk_info"][dev_name]["name"] and source_device.name != dev_name:
+        raise ValidationError(
+            "Device mapper device name mismatch: %s != %s" % (source_device.name, self["_vblk_info"][dev_name]["name"])
+        )
+
+    # Get block info using the slave source device
     try:
         blkid_info = self["_blkid_info"][f"/dev/{slave_source}"]
     except KeyError:
         if slave_source in self["_vblk_info"]:
+            # If the slave source isn't used in blkid, use the /dev/mapper path with the slave name
             blkid_info = self["_blkid_info"][f"/dev/mapper/{self['_vblk_info'][slave_source]['name']}"]
         else:
             return self.logger.warning(f"No blkid info found for device mapper slave: {c_(slave_source, 'yellow')}")
-    if source_device.name != self["_vblk_info"][dev_name]["name"] and source_device.name != dev_name:
-        raise ValidationError(
-            "Device mapper device name mismatch: %s != %s" % (source_device.name, self["_vblk_info"][dev_name]["name"])
-        )
 
     self.logger.debug(
         "[%s] Device mapper info: %s\nDevice config: %s"
         % (source_device.name, self["_vblk_info"][dev_name], blkid_info)
     )
+
+    # With the blkid info, run the appropriate autodetect function based on the type
     if blkid_info.get("type") == "crypto_LUKS" or source_device.name in self.get("cryptsetup", {}):
         autodetect_luks(self, source_device, dev_name, blkid_info)
     elif blkid_info.get("type") == "LVM2_member":
@@ -579,8 +602,19 @@ def _autodetect_dm(self, mountpoint, device=None) -> None:
             raise AutodetectError("[%s] No type found for device mapper device: %s" % (dev_name, source_device))
         raise ValidationError("Unknown device mapper device type: %s" % blkid_info.get("type"))
 
+    # Run autodetect on all slaves, in case of nested device mapper devices
     for slave in self["_vblk_info"][dev_name]["slaves"]:
         try:
+            # If the slave is a CRYPT-SUBDEV, iterate over its slaves instead
+            if self["_vblk_info"][slave]["uuid"].startswith("CRYPT-SUBDEV"):
+                for crypt_slave in self["_vblk_info"][slave]["slaves"]:
+                    _autodetect_dm(self, mountpoint, crypt_slave)
+                    self.logger.info(
+                        "[%s] Autodetected device mapper container: %s"
+                        % (c_(source_device.name, "blue", bright=True), c_(crypt_slave, "cyan"))
+                    )
+                continue
+            # Otherwise, just autodetect the slave device
             _autodetect_dm(self, mountpoint, slave)  # Just pass the slave device name, as it will be re-detected
             self.logger.info(
                 "[%s] Autodetected device mapper container: %s"

src/ugrd/fs/test_image.py

@@ -1,13 +1,14 @@
-__version__ = "2.0.0"
+__version__ = "2.1.0"
 
+from re import match
 from tempfile import TemporaryDirectory
 
 from zenlib.util import colorize as c_
 from zenlib.util import contains
 
-
 MIN_FS_SIZES = {"btrfs": 110, "f2fs": 50}
 
+
 @contains("test_flag", "A test flag must be set to create a test image", raise_exception=True)
 def init_banner(self):
     """Initialize the test image banner, set a random flag if not set."""
@@ -33,12 +34,13 @@ def _allocate_image(self, image_path, padding=0):
 
     with open(image_path, "wb") as f:
         total_size = (self.test_image_size + padding) * (2**20)  # Convert MB to bytes
-        self.logger.info(f"Allocating {self.test_image_size + padding}MB test image file: { c_(f.name, 'green')}")
-        self.logger.debug(f"[{f.name}] Total bytes: { c_(total_size, 'green')}")
+        self.logger.info(f"Allocating {self.test_image_size + padding}MB test image file: {c_(f.name, 'green')}")
+        self.logger.debug(f"[{f.name}] Total bytes: {c_(total_size, 'green')}")
         f.write(b"\0" * total_size)
 
+
 def _copy_fs_contents(self, image_path, build_dir):
-    """ Mount and copy the filesystem contents into the image,
+    """Mount and copy the filesystem contents into the image,
     for filesystems which cannot be created directly from a directory"""
     try:
         with TemporaryDirectory() as tmp_dir:
@@ -84,6 +86,14 @@ def make_test_luks_image(self, image_path):
     keyfile_path = _get_luks_keyfile(self)
     self.logger.info("Using LUKS keyfile: %s" % c_(keyfile_path, "green"))
     self.logger.info("Creating LUKS image: %s" % c_(image_path, "green"))
+    extra_args = []
+    if integrity_type := _get_luks_config(self).get("_dm-integrity"):
+        # If it's the type reported in the header like <type>(<algo>), turn it into <type>-<algo> for arg usage
+        if m := match(r"^(?P<type>\w+)\((?P<algo>[\w-]+)\)$", integrity_type):
+            integrity_type = f"{m['type']}-{m['algo']}"
+        self.logger.info(f"[{c_(image_path, 'green')}] LUKS integrity type: {c_(integrity_type, 'cyan')}")
+        extra_args.extend(["--integrity", integrity_type])
+
     self._run(
         [
             "cryptsetup",
@@ -94,6 +104,9 @@ def make_test_luks_image(self, image_path):
             "--batch-mode",
             "--key-file",
             keyfile_path,
+            "--pbkdf-memory",
+            "8192",  # Only use 8MB of memory for PBKDF to speed up test image creation and avoid high memory usage
+            *extra_args,
         ]
     )
     self.logger.info("Opening LUKS image: %s" % c_(image_path, "magenta"))

tests/test_cryptsetup.py

@@ -31,6 +31,16 @@ def test_cryptsetup_included_key(self):
         generator = InitramfsGenerator(logger=self.logger, config="tests/cryptsetup_included_key.toml")
         generator.build()
 
+    def test_cryptsetup_integrity(self):
+        """Tests LUKS based roots using a keyfile included in the initramfs with integrity protection"""
+        generator = InitramfsGenerator(
+            logger=self.logger,
+            config="tests/cryptsetup_included_key.toml",
+            _kmod_auto=["dm-integrity", "authenc"],  # Specify this because its usually auto-detected during header validation
+            cryptsetup={"root": {"_dm-integrity": "hmac(sha256)"}},  # Use the type like defined in the header, not the proper args to test processing
+        )
+        generator.build()
+
 
 if __name__ == "__main__":
     main()