From: Daan De Meyer <daan.j.demeyer@gmail.com>
Date: Wed, 15 Oct 2025 19:39:02 +0000 (+0200)
Subject: Look for .sdmagic before we consider a PE binary a UKI/addon
X-Git-Tag: v26~77
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d1b84f5fb3f62e9867aab1c6bac6583d6b112415;p=thirdparty%2Fmkosi.git

Look for .sdmagic before we consider a PE binary a UKI/addon

In ubuntu devel they started using the stubble bootloader for their
kernel images which includes a .linux and a .osrel section which means
it identifies as a UKI so we skip it. Let's additionally look for
.sdmagic as a workaround to fix this for now.

To implement this we can't make use of bootctl kernel-identify anymore
so we reimplement the logic ourselves with pefile. While we're at it,
we move KernelType to bootloader.py as it makes more sense to live there
than in qemu.py.
---

diff --git a/mkosi/__init__.py b/mkosi/__init__.py
index be4338ee7..bbe56b1ae 100644
--- a/mkosi/__init__.py
+++ b/mkosi/__init__.py
@@ -29,6 +29,7 @@ from typing import Any, Optional, Union, cast
 
 from mkosi.archive import can_extract_tar, extract_tar, make_cpio, make_tar
 from mkosi.bootloader import (
+    KernelType,
     efi_boot_binary,
     extract_pe_section,
     gen_kernel_images,
@@ -106,7 +107,6 @@ from mkosi.mounts import (
 from mkosi.pager import page
 from mkosi.partition import Partition, finalize_root, finalize_roothash
 from mkosi.qemu import (
-    KernelType,
     copy_ephemeral,
     finalize_credentials,
     finalize_kernel_command_line_extra,
diff --git a/mkosi/bootloader.py b/mkosi/bootloader.py
index c7af8a8bd..4ebf1d8f5 100644
--- a/mkosi/bootloader.py
+++ b/mkosi/bootloader.py
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
+import enum
 import itertools
 import logging
 import os
@@ -30,13 +31,52 @@ from mkosi.context import Context
 from mkosi.distributions import Distribution
 from mkosi.log import complete_step, die, log_step
 from mkosi.partition import Partition
-from mkosi.qemu import KernelType
 from mkosi.run import CompletedProcess, run, workdir
 from mkosi.sandbox import umask
-from mkosi.util import _FILE, PathString, flatten
+from mkosi.util import _FILE, PathString, StrEnum, flatten
 from mkosi.versioncomp import GenericVersion
 
 
+class KernelType(StrEnum):
+    pe = enum.auto()
+    uki = enum.auto()
+    addon = enum.auto()
+    unknown = enum.auto()
+
+    @classmethod
+    def identify(cls, config: Config, path: Path) -> "KernelType":
+        pefile = textwrap.dedent(
+            f"""\
+            import pefile
+
+            try:
+                pe = pefile.PE("{workdir(path)}", fast_load=True)
+                sections = {{s.Name.decode().strip("\\0") for s in pe.sections}}
+
+                if all(s in sections for s in (".linux", ".sdmagic", ".osrel")):
+                    print("{KernelType.uki}")
+                elif (
+                    all(s in sections for s in (".linux", ".sdmagic")) and
+                    any(s in sections for s in (".cmdline", ".dtb", ".initrd", ".ucode"))
+                ):
+                    print("{KernelType.addon}")
+                else:
+                    print("{KernelType.pe}")
+            except pefile.PEFormatError:
+                print("{KernelType.unknown}")
+            """
+        )
+
+        result = run(
+            [python_binary(config)],
+            input=pefile,
+            stdout=subprocess.PIPE,
+            sandbox=config.sandbox(options=["--ro-bind", path, workdir(path)]),
+        )
+
+        return KernelType(result.stdout.strip())
+
+
 def want_efi(config: Config) -> bool:
     # Do we want to make the image bootable on EFI firmware?
     # Note that this returns True also in the case where autodetection might later cause the system to not be
diff --git a/mkosi/qemu.py b/mkosi/qemu.py
index c3d3a7b2d..d3ea1924d 100644
--- a/mkosi/qemu.py
+++ b/mkosi/qemu.py
@@ -28,6 +28,7 @@ from collections.abc import Iterator, Sequence
 from pathlib import Path
 from typing import Optional
 
+from mkosi.bootloader import KernelType
 from mkosi.config import (
     Args,
     Config,
@@ -157,34 +158,6 @@ def find_unused_vsock_cid(config: Config, vfd: int) -> int:
     die("Failed to find an unused VSock connection ID")
 
 
-class KernelType(StrEnum):
-    pe = enum.auto()
-    uki = enum.auto()
-    unknown = enum.auto()
-
-    @classmethod
-    def identify(cls, config: Config, path: Path) -> "KernelType":
-        if not config.find_binary("bootctl"):
-            logging.warning("bootctl is not installed, assuming 'unknown' kernel type")
-            return KernelType.unknown
-
-        if (v := systemd_tool_version("bootctl", sandbox=config.sandbox)) < 253:
-            logging.warning(f"bootctl {v} doesn't know kernel-identify verb, assuming 'unknown' kernel type")
-            return KernelType.unknown
-
-        type = run(
-            ["bootctl", "kernel-identify", workdir(path)],
-            stdout=subprocess.PIPE,
-            sandbox=config.sandbox(options=["--ro-bind", path, workdir(path)]),
-        ).stdout.strip()
-
-        try:
-            return cls(type)
-        except ValueError:
-            logging.warning(f"Unknown kernel type '{type}', assuming 'unknown'")
-            return KernelType.unknown
-
-
 def find_qemu_binary(config: Config) -> Path:
     options = [f"qemu-system-{config.architecture.to_qemu()}"]