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Merged
zombiezen merged 1 commit into from
Oct 26, 2025
Merged

Store signatures in backend database and record them during realization #161

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176 changes: 176 additions & 0 deletions cmd/zb/keys.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,176 @@
// Copyright 2025 The zb Authors
// SPDX-License-Identifier: MIT

package main

import (
"cmp"
"context"
"crypto/ed25519"
"fmt"
"io"
"os"

jsonv2 "github.com/go-json-experiment/json"
"github.com/go-json-experiment/json/jsontext"
"github.com/spf13/cobra"
"zb.256lights.llc/pkg/internal/backend"
"zb.256lights.llc/pkg/zbstore"
)

type privateKeyFile struct {
Format zbstore.RealizationSignatureFormat `json:"format"`
Key []byte `json:"key,format:base64"`
}

func (f *privateKeyFile) appendToKeyring(dst *backend.Keyring) error {
switch f.Format {
case zbstore.Ed25519SignatureFormat:
if got, want := len(f.Key), ed25519.SeedSize; got != want {
return fmt.Errorf("key is wrong size (decoded is %d instead of %d bytes)", got, want)
}
dst.Ed25519 = append(dst.Ed25519, ed25519.NewKeyFromSeed(f.Key))
default:
return fmt.Errorf("unknown format %q", f.Format)
}
return nil
}

func readKeyringFromFiles(files []string) (*backend.Keyring, error) {
result := new(backend.Keyring)
for _, path := range files {
data, err := os.ReadFile(path)
if err != nil {
return nil, err
}
var parsed privateKeyFile
if err := jsonv2.Unmarshal(data, &parsed); err != nil {
return nil, fmt.Errorf("read %s: %v", path, err)
}
if err := parsed.appendToKeyring(result); err != nil {
return nil, fmt.Errorf("read %s: %v", path, err)
}
}
return result, nil
}

func newKeyCommand() *cobra.Command {
c := &cobra.Command{
Use: "key COMMAND",
Short: "operate on signing key files",
DisableFlagsInUseLine: true,
SilenceErrors: true,
SilenceUsage: true,
}
c.AddCommand(
newGenerateKeyCommand(),
newShowPublicKeyCommand(),
)
return c
}

func newGenerateKeyCommand() *cobra.Command {
c := &cobra.Command{
Use: "generate [-o PATH]",
Short: "generate a new signing key",
DisableFlagsInUseLine: true,
Args: cobra.NoArgs,
SilenceErrors: true,
SilenceUsage: true,
}
outputPath := c.Flags().StringP("output", "o", "", "`file` to write to (default is stdout)")
c.RunE = func(cmd *cobra.Command, args []string) error {
outputFile := os.Stdout
if *outputPath != "" {
var err error
outputFile, err = os.Create(*outputPath)
if err != nil {
return err
}
}
err1 := runGenerateKey(cmd.Context(), outputFile)
var err2 error
if *outputPath != "" {
err2 = outputFile.Close()
}
return cmp.Or(err1, err2)
}
return c
}

func runGenerateKey(ctx context.Context, dst io.Writer) error {
_, newKey, err := ed25519.GenerateKey(nil)
if err != nil {
return err
}
keyFile := &privateKeyFile{
Format: zbstore.Ed25519SignatureFormat,
Key: newKey.Seed(),
}
keyFileData, err := jsonv2.Marshal(keyFile, jsontext.Multiline(true))
if err != nil {
return err
}
keyFileData = append(keyFileData, '\n')
_, err = dst.Write(keyFileData)
return err
}

func newShowPublicKeyCommand() *cobra.Command {
c := &cobra.Command{
Use: "show-public [PATH [...]]",
Short: "print public key of signing keys",
DisableFlagsInUseLine: true,
Args: cobra.ArbitraryArgs,
SilenceErrors: true,
SilenceUsage: true,
}
c.RunE = func(cmd *cobra.Command, args []string) error {
ctx := cmd.Context()
if len(args) == 0 {
return runShowPublicKey(ctx, os.Stdout, os.Stdin)
}
for _, path := range args {
f, err := os.Open(path)
if err != nil {
return err
}
err = runShowPublicKey(ctx, os.Stdout, f)
f.Close()
if err != nil {
return err
}
}
return nil
}
return c
}

func runShowPublicKey(ctx context.Context, dst io.Writer, src io.Reader) error {
keyFile := new(privateKeyFile)
if err := jsonv2.UnmarshalRead(src, keyFile, jsonv2.RejectUnknownMembers(false)); err != nil {
return err
}
k := new(backend.Keyring)
if err := keyFile.appendToKeyring(k); err != nil {
return err
}
var result struct {
Format zbstore.RealizationSignatureFormat `json:"format"`
PublicKey []byte `json:"publicKey,format:base64"`
}
switch {
case len(k.Ed25519) > 0:
result.Format = zbstore.Ed25519SignatureFormat
result.PublicKey = k.Ed25519[0].Public().(ed25519.PublicKey)
default:
return nil
}
data, err := jsonv2.Marshal(result, jsontext.Multiline(true))
if err != nil {
return err
}
data = append(data, '\n')
_, err = dst.Write(data)
return err
}
1 change: 1 addition & 0 deletions cmd/zb/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,7 @@ func main() {
newBuildCommand(g),
newDerivationCommand(g),
newEvalCommand(g),
newKeyCommand(),
newNARCommand(),
newServeCommand(g),
newStoreCommand(g),
Expand Down
7 changes: 7 additions & 0 deletions cmd/zb/serve.go
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@ type serveOptions struct {
buildDir string
buildUsersGroup string
logDir string
keyFiles []string
sandbox bool
sandboxPaths map[string]backend.SandboxPath
allowKeepFailed bool
Expand Down Expand Up @@ -82,6 +83,7 @@ func newServeCommand(g *globalConfig) *cobra.Command {
c.Flags().StringVar(&opts.buildDir, "build-root", os.TempDir(), "`dir`ectory to store temporary build artifacts")
c.Flags().StringVar(&opts.logDir, "log-directory", filepath.Join(filepath.Dir(string(zbstore.DefaultDirectory())), "var", "log", "zb"), "`dir`ectory to store builder logs in")
c.Flags().StringVar(&opts.buildUsersGroup, "build-users-group", opts.buildUsersGroup, "name of Unix `group` of users to run builds as")
c.Flags().StringArrayVar(&opts.keyFiles, "signing-key", nil, "key `file` for signing realizations (can be passed multiple times)")
c.Flags().BoolVar(&opts.sandbox, "sandbox", opts.sandbox, "run builders in a restricted environment")
sandboxPaths := make(map[string]string)
c.Flags().Var(pathMapFlag(sandboxPaths), "sandbox-path", "`path` to allow in sandbox (can be passed multiple times)")
Expand Down Expand Up @@ -113,6 +115,10 @@ func runServe(ctx context.Context, g *globalConfig, opts *serveOptions) error {
}
return fmt.Errorf("sandboxing requested but unable to use (are you running with admin privileges?)")
}
keyring, err := readKeyringFromFiles(opts.keyFiles)
if err != nil {
return err
}
storeDirGroupID, buildUsers, err := buildUsersForGroup(ctx, opts.buildUsersGroup)
if err != nil {
return err
Expand Down Expand Up @@ -203,6 +209,7 @@ func runServe(ctx context.Context, g *globalConfig, opts *serveOptions) error {
AllowKeepFailed: opts.allowKeepFailed,
CoresPerBuild: opts.coresPerBuild,
BuildLogRetention: opts.buildLogRetention,
Keyring: keyring,
})
defer func() {
if err := backendServer.Close(); err != nil {
Expand Down
52 changes: 52 additions & 0 deletions internal/backend/backend.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ package backend

import (
"context"
"crypto/ed25519"
"errors"
"fmt"
"io"
Expand Down Expand Up @@ -83,6 +84,10 @@ type Options struct {
// BuildLogRetention is the length of time to retain build logs.
// If non-positive, then build logs will be not be automatically deleted.
BuildLogRetention time.Duration

// Keyring is a set of keys that will be used to sign realizations
// that this server realizes.
Keyring *Keyring
}

// A SandboxPath is the set of options for SandboxPaths in [Options].
Expand Down Expand Up @@ -128,6 +133,7 @@ type Server struct {
db *sqlitemigration.Pool
allowKeepFailed bool
buildContext func(context.Context, string) context.Context
keyring *Keyring

sandbox bool
sandboxPaths map[string]SandboxPath
Expand Down Expand Up @@ -169,6 +175,7 @@ func NewServer(dir zbstore.Directory, dbPath string, opts *Options) *Server {
users: users,
activeBuilds: make(map[uuid.UUID]context.CancelFunc),
buildContext: opts.BuildContext,
keyring: opts.Keyring.Clone(),

db: sqlitemigration.NewPool(dbPath, loadSchema(), sqlitemigration.Options{
Flags: sqlite.OpenCreate | sqlite.OpenReadWrite,
Expand Down Expand Up @@ -894,6 +901,51 @@ func (s *Server) optimizeDatabase(ctx context.Context) {
}
}

// A Keyring is a set of private keys to use for signing.
// Nil or the zero value is an empty set of keys.
type Keyring struct {
Ed25519 []ed25519.PrivateKey
}

// Clone returns a new keyring with contents identical to k.
// If k is nil, then Clone returns nil.
func (k *Keyring) Clone() *Keyring {
if k == nil {
return nil
}
k2 := new(Keyring)
if len(k.Ed25519) > 0 {
k2.Ed25519 = make([]ed25519.PrivateKey, len(k.Ed25519))
for i, key := range k.Ed25519 {
k2.Ed25519[i] = slices.Clone(key)
}
}
return k2
}

// Sign creates signatures for the realization using all the private keys in the keyring.
func (k *Keyring) Sign(ref zbstore.RealizationOutputReference, r *zbstore.Realization) ([]*zbstore.RealizationSignature, error) {
n := 0
if k != nil {
n = len(k.Ed25519)
}
if n == 0 {
return nil, nil
}

result := make([]*zbstore.RealizationSignature, 0, n)
var returnedError error
for _, key := range k.Ed25519 {
sig, err := zbstore.SignRealizationWithEd25519(ref, r, key)
if err != nil {
returnedError = errors.Join(returnedError, err)
continue
}
result = append(result, sig)
}
return result, returnedError
}

func parseBuildID(id string) (_ uuid.UUID, ok bool) {
u, err := uuid.Parse(id)
if err != nil || id != u.String() {
Expand Down
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