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// Copyright 2024 The Update Framework Authors
//
// 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
//
// SPDX-License-Identifier: Apache-2.0
//
package main
import (
"crypto"
"crypto/ed25519"
"fmt"
"os"
"path/filepath"
"strings"
"time"
"github.com/sigstore/sigstore/pkg/signature"
"github.com/theupdateframework/go-tuf/v2/metadata"
"github.com/theupdateframework/go-tuf/v2/metadata/repository"
)
func main() {
// Create top-level metadata
roles := repository.New()
keys := map[string]ed25519.PrivateKey{}
// Create Targets metadata
targets := metadata.Targets(helperExpireIn(10))
roles.SetTargets("targets", targets)
// Add each target to Targets metadata
for _, targetName := range []string{"targets/map.json", "targets/sigstore-tuf-root/root.json", "targets/staging/root.json"} {
targetPath, localPath := helperGetPathForTarget(targetName)
targetFileInfo, err := metadata.TargetFile().FromFile(localPath, "sha256")
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "generating target file info failed", err))
}
roles.Targets("targets").Signed.Targets[strings.TrimPrefix(targetPath, "targets/")] = targetFileInfo
for _, eachHashValue := range targetFileInfo.Hashes {
err := copyHashPrefixed(localPath, eachHashValue.String())
if err != nil {
panic(err)
}
}
}
// Create Snapshot metadata
snapshot := metadata.Snapshot(helperExpireIn(10))
roles.SetSnapshot(snapshot)
// Create Timestamp metadata
timestamp := metadata.Timestamp(helperExpireIn(10))
roles.SetTimestamp(timestamp)
// Create Root metadata
root := metadata.Root(helperExpireIn(10))
roles.SetRoot(root)
// For this example, we generate one private key of type 'ed25519' for each top-level role
for _, name := range []string{"targets", "snapshot", "timestamp", "root"} {
_, private, err := ed25519.GenerateKey(nil)
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "key generation failed", err))
}
keys[name] = private
key, err := metadata.KeyFromPublicKey(private.Public())
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "key conversion failed", err))
}
err = roles.Root().Signed.AddKey(key, name)
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "adding key to root failed", err))
}
}
// Sign top-level metadata (in-band)
for _, name := range []string{"targets", "snapshot", "timestamp", "root"} {
key := keys[name]
signer, err := signature.LoadSigner(key, crypto.Hash(0))
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "loading a signer failed", err))
}
switch name {
case "targets":
_, err = roles.Targets("targets").Sign(signer)
case "snapshot":
_, err = roles.Snapshot().Sign(signer)
case "timestamp":
_, err = roles.Timestamp().Sign(signer)
case "root":
_, err = roles.Root().Sign(signer)
}
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "metadata signing failed", err))
}
}
// Persist metadata (consistent snapshot)
cwd, err := os.Getwd()
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "getting cwd failed", err))
}
// Save to metadata folder
cwd = filepath.Join(cwd, "metadata")
for _, name := range []string{"targets", "snapshot", "timestamp", "root"} {
switch name {
case "targets":
filename := fmt.Sprintf("%d.%s.json", roles.Targets("targets").Signed.Version, name)
err = roles.Targets("targets").ToFile(filepath.Join(cwd, filename), true)
case "snapshot":
filename := fmt.Sprintf("%d.%s.json", roles.Snapshot().Signed.Version, name)
err = roles.Snapshot().ToFile(filepath.Join(cwd, filename), true)
case "timestamp":
filename := fmt.Sprintf("%s.json", name)
err = roles.Timestamp().ToFile(filepath.Join(cwd, filename), true)
case "root":
filename := fmt.Sprintf("%d.%s.json", roles.Root().Signed.Version, name)
err = roles.Root().ToFile(filepath.Join(cwd, filename), true)
}
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "saving metadata to file failed", err))
}
}
// Save the created root metadata in the client folder, this is the initial trusted root metadata
err = roles.Root().ToFile(filepath.Join(cwd, "../../client/root.json"), true)
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "saving trusted root metadata to client folder failed", err))
}
// Verify that metadata is signed correctly
// Verify root
err = roles.Root().VerifyDelegate("root", roles.Root())
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "verifying root metadata failed", err))
}
// Verify targets
err = roles.Root().VerifyDelegate("targets", roles.Targets("targets"))
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "verifying targets metadata failed", err))
}
// Verify snapshot
err = roles.Root().VerifyDelegate("snapshot", roles.Snapshot())
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "verifying snapshot metadata failed", err))
}
// Verify timestamp
err = roles.Root().VerifyDelegate("timestamp", roles.Timestamp())
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "verifying timestamp metadata failed", err))
}
fmt.Println("Done! Metadata files location:", cwd)
}
// helperExpireIn returns time offset by years (for the sake of the example)
func helperExpireIn(years int) time.Time {
return time.Now().AddDate(years, 0, 0).UTC()
}
// helperGetPathForTarget returns local and target paths for target
func helperGetPathForTarget(name string) (string, string) {
cwd, err := os.Getwd()
if err != nil {
panic(fmt.Sprintln("generate_metadata.go:", "getting cwd failed", err))
}
// _, dir := filepath.Split(cwd)
// return filepath.Join(dir, name), filepath.Join(cwd, name)
return name, filepath.Join(cwd, name)
}
func copyHashPrefixed(src string, hash string) error {
data, err := os.ReadFile(src)
if err != nil {
return err
}
dirName, fileName := filepath.Split(src)
err = os.WriteFile(filepath.Join(dirName, fmt.Sprintf("%s.%s", hash, fileName)), data, 0644)
if err != nil {
return err
}
return nil
}
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