efivarfs, osimage: fix boot entry handling
efivarfs was updated to handle partition UUIDs in the mixed-endian
format [1], enabling it to produce correct boot entries. Its interface
was changed in the process, leading to further changes in osimage.
In addition, BootEntry.Marshal will replace any backslash with a
forward slash in the EFI executable path.
[1] https://en.wikipedia.org/wiki/Universally_unique_identifier#Encoding
Change-Id: Ib8300e01fd1664d0c08bb033b1dc36addb925b20
Reviewed-on: https://review.monogon.dev/c/monogon/+/456
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/node/build/mkimage/osimage/BUILD.bazel b/metropolis/node/build/mkimage/osimage/BUILD.bazel
index d9cacae..88f1dd8 100644
--- a/metropolis/node/build/mkimage/osimage/BUILD.bazel
+++ b/metropolis/node/build/mkimage/osimage/BUILD.bazel
@@ -11,5 +11,6 @@
"@com_github_diskfs_go_diskfs//disk:go_default_library",
"@com_github_diskfs_go_diskfs//filesystem:go_default_library",
"@com_github_diskfs_go_diskfs//partition/gpt:go_default_library",
+ "@com_github_google_uuid//:go_default_library",
],
)
diff --git a/metropolis/node/build/mkimage/osimage/osimage.go b/metropolis/node/build/mkimage/osimage/osimage.go
index 2f000a6..5aeeccd 100644
--- a/metropolis/node/build/mkimage/osimage/osimage.go
+++ b/metropolis/node/build/mkimage/osimage/osimage.go
@@ -27,6 +27,7 @@
"github.com/diskfs/go-diskfs/disk"
"github.com/diskfs/go-diskfs/filesystem"
"github.com/diskfs/go-diskfs/partition/gpt"
+ "github.com/google/uuid"
"source.monogon.dev/metropolis/pkg/efivarfs"
)
@@ -372,10 +373,14 @@
t, err := diskImg.GetPartitionTable()
p := t.GetPartitions()
esp := (p[0]).(*gpt.Partition)
+ guid, err := uuid.Parse(esp.GUID)
+ if err != nil {
+ return nil, fmt.Errorf("couldn't parse the GPT GUID: %w", err)
+ }
be := efivarfs.BootEntry{
Description: "Metropolis",
Path: EFIPayloadPath,
- PartitionGUID: esp.GUID,
+ PartitionGUID: guid,
PartitionNumber: 1,
PartitionStart: esp.Start,
PartitionSize: esp.End - esp.Start + 1,
diff --git a/metropolis/pkg/efivarfs/BUILD.bazel b/metropolis/pkg/efivarfs/BUILD.bazel
index 3b1e0b0..c41bb88 100644
--- a/metropolis/pkg/efivarfs/BUILD.bazel
+++ b/metropolis/pkg/efivarfs/BUILD.bazel
@@ -5,10 +5,12 @@
srcs = [
"boot.go",
"efivarfs.go",
+ "format.go",
],
importpath = "source.monogon.dev/metropolis/pkg/efivarfs",
visibility = ["//visibility:public"],
deps = [
+ "@com_github_google_uuid//:go_default_library",
"@org_golang_x_text//encoding/unicode:go_default_library",
"@org_golang_x_text//transform:go_default_library",
],
diff --git a/metropolis/pkg/efivarfs/boot.go b/metropolis/pkg/efivarfs/boot.go
index 096ec7c..4178c8d 100644
--- a/metropolis/pkg/efivarfs/boot.go
+++ b/metropolis/pkg/efivarfs/boot.go
@@ -26,7 +26,9 @@
import (
"fmt"
"math"
+ "strings"
+ "github.com/google/uuid"
"golang.org/x/text/transform"
)
@@ -51,7 +53,7 @@
type BootEntry struct {
Description string // eg. "Linux Boot Manager"
Path string // eg. `\EFI\systemd\systemd-bootx64.efi`
- PartitionGUID string
+ PartitionGUID uuid.UUID
PartitionNumber uint32 // Starts with 1
PartitionStart uint64 // LBA
PartitionSize uint64 // LBA
@@ -63,7 +65,7 @@
// as attributes of an EFI variable) are always set to LOAD_OPTION_ACTIVE.
func (t *BootEntry) Marshal() ([]byte, error) {
if t.Description == "" ||
- t.PartitionGUID == "00000000-0000-0000-0000-000000000000" ||
+ t.PartitionGUID.String() == "00000000-0000-0000-0000-000000000000" ||
t.Path == "" ||
t.PartitionNumber == 0 ||
t.PartitionStart == 0 ||
@@ -83,7 +85,9 @@
dp = append32(dp, t.PartitionNumber)
dp = append64(dp, t.PartitionStart)
dp = append64(dp, t.PartitionSize)
- dp = append(dp, t.PartitionGUID[0:16]...) // Partition Signature
+ // Append the partition GUID in the EFI format.
+ dp = append(dp, MarshalEFIGUID(t.PartitionGUID)...)
+
dp = append(dp,
0x02, // Partition Format ("GUID Partition Table")
0x02, // Signature Type ("GUID signature")
@@ -91,7 +95,8 @@
// EFI_LOAD_OPTION.FilePathList[1]
enc := Encoding.NewEncoder()
- path, _, e := transform.Bytes(enc, []byte(t.Path))
+ bsp := strings.ReplaceAll(t.Path, "/", "\\")
+ path, _, e := transform.Bytes(enc, []byte(bsp))
if e != nil {
return nil, fmt.Errorf("while encoding Path: %v", e)
}
diff --git a/metropolis/pkg/efivarfs/format.go b/metropolis/pkg/efivarfs/format.go
new file mode 100644
index 0000000..a71dbf9
--- /dev/null
+++ b/metropolis/pkg/efivarfs/format.go
@@ -0,0 +1,33 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package efivarfs
+
+import (
+ "github.com/google/uuid"
+)
+
+// MarshalEFIGUID returns src represented in the EFI GUID format, as defined in
+// UEFI specification, version 2.9, appendix A:
+// https://uefi.org/sites/default/files/resources/UEFI_Spec_2_9_2021_03_18.pdf
+func MarshalEFIGUID(src uuid.UUID) []byte {
+ efi := make([]byte, 16)
+ transform := []int{3, 2, 1, 0, 5, 4, 7, 6, 8, 9, 10, 11, 12, 13, 14, 15}
+ for dest, from := range transform {
+ efi[dest] = src[from]
+ }
+ return efi
+}