Parse UKIs produced by ukify

ecleankernel/file.py

@@ -6,6 +6,7 @@
 import enum
 import errno
 import importlib
+import logging
 import os
 import shutil
 import struct
@@ -247,16 +248,29 @@ def read_version_from_efi(self,
                 if len(buf) != 40:
                     raise UnrecognizedKernelError(
                         f"PE file {self.path}: EOF in section table!")
-                if buf[:8] == b".linux\0\0":
-                    offset = struct.unpack_from("<I", buf, 20)[0]
+                size = struct.unpack_from("<I", buf, 8)[0]
+                offset = struct.unpack_from("<I", buf, 20)[0]
+                if buf[:8] == b".uname\0\0":
+                    # ukify writes uname -r output into the .uname section
+                    # https://uapi-group.org/specifications/specs/unified_kernel_image/
+                    f.seek(initial_offset + offset)
+                    # the ' (ukify)' suffix is a hack to avoid raising
+                    # an exception in read_internal_version()
+                    ver = f.read(size) + b' (ukify)'
+                    logging.debug(
+                        f"Found version {ver!r} in '.uname' section")
+                    return ver
+                elif buf[:8] == b".linux\0\0":
                     f.seek(initial_offset + offset)
                     for func in (self.read_version_from_bzimage,
                                  self.read_version_from_raw,
                                  ):
                         verbuf = func(f)
                         if verbuf is not None:
+                            logging.debug(
+                                f"Found version {verbuf!r} in"
+                                f" '.linux' section (generic)")
                             return verbuf
-                    break
             return None
 
     def __repr__(self) -> str:

test/test_file.py

@@ -56,6 +56,7 @@ def write_compress(path: Path,
 
 def write_efistub(path: Path,
                   version_line: bytes,
+                  uname: bool = False,
                   ) -> None:
     """Write an EFIstub kernel image at `path`, with `version_line`"""
 
@@ -68,23 +69,34 @@ def write_efistub(path: Path,
         f.write(b"PE\0\0\0\0\4\0" + 12 * b"\0" + b"\x08\0\0\0")
         # opt header (padding)
         f.write(8 * b"\0")
-        # 4 sections
+        # 5 sections
+        section = b".cmdline"
+        val = b"\0\0\0\0"
+        if uname:
+            section = b".uname\0\0" + bytes([len(version_line)])
+            val = b"\x68\1\0\0"
+
         sections = {
             b".code": b"\0\0\0\0",
             b".data": b"\0\0\0\0",
-            b".linux": b"\x80\1\0\0",
+            section: val,
+            b".linux": b"\xA8\1\0\0",
             b".initrd": b"\0\0\0\0",
         }
         for name, offset in sections.items():
             f.write(name + (20 - len(name)) * b"\0" + offset + 16 * b"\0")
-        # padding
-        f.write(64 * b"\0")
+        # .uname/padding
+        if uname:
+            f.write(version_line + (64 - len(version_line)) * b'\0')
+        else:
+            f.write(64 * b'\0')
         # bzImage
         f.write(0x202 * b'\0')
         f.write(b'HdrS')
         f.write(8 * b'\0')
         f.write(b'\x10\x00')
-        f.write(version_line)
+        if not uname:
+            f.write(version_line)
 
 
 class KernelImageTests(unittest.TestCase):
@@ -122,6 +134,20 @@ def test_read_internal_version_efistub(self) -> None:
             KernelImage(path).read_internal_version(),
             "1.2.3")
 
+    def test_read_internal_version_efistub_uname(self) -> None:
+        path = Path(self.td.name) / "vmlinuz"
+        write_efistub(path, b"1.2.3 built on test", True)
+        self.assertEqual(
+            KernelImage(path).read_internal_version(),
+            "1.2.3")
+
+    def test_read_internal_version_efistub_uname_nowhitespace(self) -> None:
+        path = Path(self.td.name) / "vmlinuz"
+        write_efistub(path, b"1.2.3", True)
+        self.assertEqual(
+            KernelImage(path).read_internal_version(),
+            "1.2.3")
+
     def test_very_short(self) -> None:
         path = Path(self.td.name) / 'vmlinuz'
         with open(path, 'wb') as f: