measure: introduce support for a .fmw section

UKIs container can be used to bundle a firmware image that can be measured and
used on a confidential computing environment. Add support to introduce a .fmw
section in UKI that can be used for a firmware image. ukify tool has been
also changed to support addition of a firmware image in UKI. For example:

ukify.py build \
        --stub ./build/src/boot/efi/linuxx64.efi.stub \
        --linux bzImage \
        --cmdline='blah blah debug' \
        --firmware ~/OVMF.fd \
        --output=root/efi/boot/bootx64.efi

Co-authored-by: harald.hoyer@gmail.com

man/systemd-stub.xml

@@ -75,6 +75,9 @@
       <listitem><para>An optional <literal>.ucode</literal> section with an initrd containing microcode, to
       be handed to the kernel before any other initrd. This initrd must not be compressed.</para></listitem>
 
+      <listitem><para>An optional <literal>.fmw</literal> section with the firmware image.
+      </para></listitem>
+
       <listitem><para>An optional <literal>.splash</literal> section with an image (in the Windows
       <filename>.BMP</filename> format) to show on screen before invoking the kernel.</para></listitem>
 

src/fundamental/uki.c

@@ -23,5 +23,6 @@ const char* const unified_sections[_UNIFIED_SECTION_MAX + 1] = {
         [UNIFIED_SECTION_PROFILE]    = ".profile",
         [UNIFIED_SECTION_DTBAUTO]    = ".dtbauto",
         [UNIFIED_SECTION_HWIDS]      = ".hwids",
+        [UNIFIED_SECTION_FIRMWARE]   = ".fmw",
         NULL,
 };

src/fundamental/uki.h

@@ -20,6 +20,7 @@ typedef enum UnifiedSection {
         UNIFIED_SECTION_PROFILE,
         UNIFIED_SECTION_DTBAUTO,
         UNIFIED_SECTION_HWIDS,
+        UNIFIED_SECTION_FIRMWARE,
         _UNIFIED_SECTION_MAX,
 } UnifiedSection;
 

src/measure/measure.c

@@ -105,6 +105,7 @@ static int help(int argc, char *argv[], void *userdata) {
                "     --linux=PATH        Path to Linux kernel image file        %7$s .linux\n"
                "     --osrel=PATH        Path to os-release file                %7$s .osrel\n"
                "     --cmdline=PATH      Path to file with kernel command line  %7$s .cmdline\n"
+               "     --firmware=PATH     Path to firmware image file            %7$s .fmw\n"
                "     --initrd=PATH       Path to initrd image file              %7$s .initrd\n"
                "     --ucode=PATH        Path to microcode image file           %7$s .ucode\n"
                "     --splash=PATH       Path to splash bitmap file             %7$s .splash\n"
@@ -159,8 +160,9 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_PCRPKEY,
                 ARG_PROFILE,
                 ARG_HWIDS,
+                ARG_DTBAUTO,
                 _ARG_SECTION_LAST,
-                ARG_DTBAUTO = _ARG_SECTION_LAST,
+                ARG_FIRMWARE = _ARG_SECTION_LAST,
                 ARG_BANK,
                 ARG_PRIVATE_KEY,
                 ARG_PRIVATE_KEY_SOURCE,
@@ -181,6 +183,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "osrel",              required_argument, NULL, ARG_OSREL              },
                 { "cmdline",            required_argument, NULL, ARG_CMDLINE            },
                 { "initrd",             required_argument, NULL, ARG_INITRD             },
+                { "firmware",           required_argument, NULL, ARG_FIRMWARE           },
                 { "ucode",              required_argument, NULL, ARG_UCODE              },
                 { "splash",             required_argument, NULL, ARG_SPLASH             },
                 { "dtb",                required_argument, NULL, ARG_DTB                },

src/ukify/ukify.py

@@ -240,6 +240,7 @@ class UkifyConfig:
     devicetree: Path
     efi_arch: str
     initrd: list[Path]
+    firmware: Path
     join_profiles: list[Path]
     json: Union[Literal['pretty'], Literal['short'], Literal['off']]
     linux: Optional[Path]
@@ -362,6 +363,7 @@ class Uname:
 DEFAULT_SECTIONS_TO_SHOW = {
     '.linux':   'binary',
     '.initrd':  'binary',
+    '.fmw':     'binary',
     '.ucode':   'binary',
     '.splash':  'binary',
     '.dtb':     'binary',
@@ -1050,6 +1052,7 @@ def make_uki(opts: UkifyConfig) -> None:
         ('.splash',  opts.splash,     True),
         ('.pcrpkey', pcrpkey,         True),
         ('.initrd',  initrd,          True),
+        ('.fmw',     opts.firmware,   True),
         ('.ucode',   opts.microcode,  True),
     ]  # fmt: skip
 
@@ -1106,6 +1109,7 @@ def make_uki(opts: UkifyConfig) -> None:
         '.osrel',
         '.cmdline',
         '.initrd',
+        '.fmw',
         '.ucode',
         '.splash',
         '.dtb',
@@ -1584,6 +1588,12 @@ CONFIG_ITEMS = [
         config_key='UKI/Initrd',
         config_push=ConfigItem.config_list_prepend,
     ),
+    ConfigItem(
+        '--firmware',
+        type=Path,
+        help='firmware file [.fmw section]',
+        config_key='UKI/Firmware',
+    ),
     ConfigItem(
         '--microcode',
         metavar='UCODE',