forked from aptly-dev/aptly
/
internal.go
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/
internal.go
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package pgp
import (
"bytes"
"fmt"
"io"
"os"
"path/filepath"
"sort"
"strings"
"syscall"
"time"
"github.com/pkg/errors"
// TODO: replace crypto/openpgp since it is deprecated
// https://github.com/golang/go/issues/44226
"github.com/ProtonMail/go-crypto/openpgp" //nolint:staticcheck
"github.com/ProtonMail/go-crypto/openpgp/clearsign" //nolint:staticcheck
openpgp_errors "github.com/ProtonMail/go-crypto/openpgp/errors" //nolint:staticcheck
"github.com/ProtonMail/go-crypto/openpgp/packet" //nolint:staticcheck
"golang.org/x/term"
)
// Test interface
var (
_ Signer = &GoSigner{}
_ Verifier = &GoVerifier{}
)
// Internal errors
var (
errWrongPassphrase = errors.New("unable to decrypt the key, passphrase is wrong")
)
// GoSigner is implementation of Signer interface using Go internal OpenPGP library
type GoSigner struct {
keyRef string
keyringFile, secretKeyringFile string
passphrase, passphraseFile string
batch bool
publicKeyring openpgp.EntityList
secretKeyring openpgp.EntityList
signer *openpgp.Entity
signerConfig *packet.Config
}
// SetBatch controls whether we allowed to interact with user
func (g *GoSigner) SetBatch(batch bool) {
g.batch = batch
}
// SetKey sets key ID to use when signing files
func (g *GoSigner) SetKey(keyRef string) {
g.keyRef = keyRef
}
// SetKeyRing allows to set custom keyring and secretkeyring
func (g *GoSigner) SetKeyRing(keyring, secretKeyring string) {
g.keyringFile, g.secretKeyringFile = keyring, secretKeyring
}
// SetPassphrase sets passphrase params
func (g *GoSigner) SetPassphrase(passphrase, passphraseFile string) {
g.passphrase, g.passphraseFile = passphrase, passphraseFile
}
// Init verifies availability of gpg & presence of keys
func (g *GoSigner) Init() error {
g.signerConfig = &packet.Config{
DefaultCompressionAlgo: packet.CompressionZLIB,
CompressionConfig: &packet.CompressionConfig{
Level: 9,
},
}
if g.passphraseFile != "" {
passF, err := os.Open(g.passphraseFile)
if err != nil {
return errors.Wrap(err, "error opening passphrase file")
}
defer passF.Close()
contents, err := io.ReadAll(passF)
if err != nil {
return errors.Wrap(err, "error reading passphrase file")
}
g.passphrase = strings.TrimSpace(string(contents))
}
if g.keyringFile == "" {
g.keyringFile = "pubring.gpg"
}
if g.secretKeyringFile == "" {
g.secretKeyringFile = "secring.gpg"
}
var err error
g.publicKeyring, err = loadKeyRing(g.keyringFile, false)
if err != nil {
return errors.Wrap(err, "error loading public keyring")
}
g.secretKeyring, err = loadKeyRing(g.secretKeyringFile, false)
if err != nil {
return errors.Wrap(err, "error load secret keyring")
}
if g.keyRef == "" {
// no key reference, pick the first key
for _, signer := range g.secretKeyring {
if !validEntity(signer) {
continue
}
g.signer = signer
break
}
if g.signer == nil {
return fmt.Errorf("looks like there are no keys in gpg, please create one (official manual: http://www.gnupg.org/gph/en/manual.html)")
}
} else {
pickKeyLoop:
for _, signer := range g.secretKeyring {
key := KeyFromUint64(signer.PrimaryKey.KeyId)
if key.Matches(Key(g.keyRef)) {
g.signer = signer
break
}
if !validEntity(signer) {
continue
}
for name := range signer.Identities {
if strings.Contains(name, g.keyRef) {
g.signer = signer
break pickKeyLoop
}
}
}
if g.signer == nil {
return errors.Errorf("couldn't find key for key reference %v", g.keyRef)
}
}
if g.signer.PrivateKey.Encrypted {
i := 0
for name := range g.signer.Identities {
if i == 0 {
fmt.Printf("openpgp: Passphrase is required to unlock private key \"%s\"\n", name)
} else {
fmt.Printf(" aka \"%s\"\n", name)
}
i++
}
fmt.Printf("openpgp: %s-bit %s key, ID %s, created %s\n",
keyBits(g.signer.PrimaryKey.PublicKey),
pubkeyAlgorithmName(g.signer.PrimaryKey.PubKeyAlgo),
KeyFromUint64(g.signer.PrimaryKey.KeyId),
g.signer.PrimaryKey.CreationTime.Format("2006-01-02"))
if g.passphrase == "" {
if g.batch {
return errors.New("key is locked with passphrase, but no passphrase was given in batch mode")
}
for attempt := 0; attempt < 3; attempt++ {
fmt.Print("\nEnter passphrase: ")
var bytePassphrase []byte
bytePassphrase, err = term.ReadPassword(int(syscall.Stdin))
if err != nil {
return errors.Wrap(err, "error reading passphare")
}
g.passphrase = string(bytePassphrase)
err = g.decryptKey()
if err == nil || err != errWrongPassphrase {
break
}
fmt.Print("\nWrong passphrase, please try again.\n")
}
} else {
err = g.decryptKey()
}
if err != nil {
return err
}
}
return nil
}
func (g *GoSigner) decryptKey() error {
err := g.signer.PrivateKey.Decrypt([]byte(g.passphrase))
if err == nil {
return nil
}
if e, ok := err.(openpgp_errors.StructuralError); ok {
if string(e) == "private key checksum failure" {
return errWrongPassphrase
}
}
return errors.Wrap(err, "error unlocking private key")
}
// DetachedSign signs file with detached signature in ASCII format
func (g *GoSigner) DetachedSign(source string, destination string) error {
fmt.Printf("openpgp: signing file '%s'...\n", filepath.Base(source))
message, err := os.Open(source)
if err != nil {
return errors.Wrap(err, "error opening source file")
}
defer message.Close()
signature, err := os.Create(destination)
if err != nil {
return errors.Wrap(err, "error creating signature file")
}
defer signature.Close()
err = openpgp.ArmoredDetachSign(signature, g.signer, message, g.signerConfig)
if err != nil {
return errors.Wrap(err, "error creating detached signature")
}
return nil
}
// ClearSign clear-signs the file
func (g *GoSigner) ClearSign(source string, destination string) error {
fmt.Printf("openpgp: clearsigning file '%s'...\n", filepath.Base(source))
message, err := os.Open(source)
if err != nil {
return errors.Wrap(err, "error opening source file")
}
defer message.Close()
clearsigned, err := os.Create(destination)
if err != nil {
return errors.Wrap(err, "error creating clearsigned file")
}
defer clearsigned.Close()
stream, err := clearsign.Encode(clearsigned, g.signer.PrivateKey, g.signerConfig)
if err != nil {
return errors.Wrap(err, "error initializing clear signer")
}
_, err = io.Copy(stream, message)
if err != nil {
stream.Close()
return errors.Wrap(err, "error generating clearsigned signature")
}
err = stream.Close()
if err != nil {
return errors.Wrap(err, "error generating clearsigned signature")
}
return nil
}
// GoVerifier is implementation of Verifier interface using Go internal OpenPGP library
type GoVerifier struct {
keyRingFiles []string
trustedKeyring openpgp.EntityList
}
// InitKeyring verifies that gpg is installed and some keys are trusted
func (g *GoVerifier) InitKeyring() error {
var err error
if len(g.keyRingFiles) == 0 {
g.trustedKeyring, err = loadKeyRing("trustedkeys.gpg", true)
if err != nil {
return errors.Wrap(err, "failure loading trustedkeys.gpg keyring")
}
} else {
for _, file := range g.keyRingFiles {
var keyring openpgp.EntityList
keyring, err = loadKeyRing(file, false)
if err != nil {
return errors.Wrapf(err, "failure loading %s keyring", file)
}
g.trustedKeyring = append(g.trustedKeyring, keyring...)
}
}
if len(g.trustedKeyring) == 0 {
fmt.Printf("\nLooks like your keyring with trusted keys is empty. You might consider importing some keys.\n")
if len(g.keyRingFiles) == 0 {
// using default keyring
fmt.Printf("If you're running Debian or Ubuntu, it's a good idea to import current archive keys by running:\n\n")
fmt.Printf(" gpg --no-default-keyring --keyring /usr/share/keyrings/debian-archive-keyring.gpg --export | gpg --no-default-keyring --keyring trustedkeys.gpg --import\n")
fmt.Printf("\n(for Ubuntu, use /usr/share/keyrings/ubuntu-archive-keyring.gpg)\n\n")
}
}
return nil
}
// AddKeyring adds custom keyrings to the list
func (g *GoVerifier) AddKeyring(keyring string) {
g.keyRingFiles = append(g.keyRingFiles, keyring)
}
func (g *GoVerifier) showImportKeyTip(signers []signatureResult) {
if len(g.keyRingFiles) == 0 {
fmt.Printf("\nLooks like some keys are missing in your trusted keyring, you may consider importing them from keyserver:\n\n")
keys := make([]string, 0)
for _, signer := range signers {
if signer.Entity != nil {
continue
}
keys = append(keys, string(KeyFromUint64(signer.IssuerKeyID)))
}
fmt.Printf("gpg --no-default-keyring --keyring trustedkeys.gpg --keyserver keyserver.ubuntu.com --recv-keys %s\n\n",
strings.Join(keys, " "))
fmt.Printf("Sometimes keys are stored in repository root in file named Release.key, to import such key:\n\n")
fmt.Printf("wget -O - https://some.repo/repository/Release.key | gpg --no-default-keyring --keyring trustedkeys.gpg --import\n\n")
}
}
func (g *GoVerifier) printLog(signers []signatureResult) {
for _, signer := range signers {
fmt.Printf("openpgp: Signature made %s using %s key ID %s\n",
signer.CreationTime.Format(time.RFC1123),
pubkeyAlgorithmName(signer.PubKeyAlgo),
KeyFromUint64(signer.IssuerKeyID))
if signer.Entity != nil {
i := 0
names := make([]string, 0, len(signer.Entity.Identities))
for name := range signer.Entity.Identities {
names = append(names, name)
}
sort.Strings(names)
for _, name := range names {
if i == 0 {
fmt.Printf("openpgp: Good signature from \"%s\"\n", name)
} else {
fmt.Printf(" aka \"%s\"\n", name)
}
i++
}
} else {
fmt.Printf("openpgp: Can't check signature: public key not found\n")
}
}
}
// VerifyDetachedSignature verifies combination of signature and cleartext using gpgv
func (g *GoVerifier) VerifyDetachedSignature(signature, cleartext io.Reader, showKeyTip bool) error {
var signatureBuf bytes.Buffer
signers, missingKeys, err := checkArmoredDetachedSignature(g.trustedKeyring, cleartext, io.TeeReader(signature, &signatureBuf))
if err == io.EOF {
// most probably not armored signature
signers, missingKeys, err = checkDetachedSignature(g.trustedKeyring, cleartext, &signatureBuf)
}
g.printLog(signers)
if showKeyTip && missingKeys > 0 {
g.showImportKeyTip(signers)
}
if err != nil {
return errors.Wrap(err, "failed to verify detached signature")
}
return nil
}
// IsClearSigned returns true if file contains signature
func (g *GoVerifier) IsClearSigned(clearsigned io.Reader) (bool, error) {
signedBuffer, err := io.ReadAll(clearsigned)
if err != nil {
return false, errors.Wrap(err, "failed to read clearsigned data")
}
block, _ := clearsign.Decode(signedBuffer)
return block != nil, nil
}
// VerifyClearsigned verifies clearsigned file using gpgv
func (g *GoVerifier) VerifyClearsigned(clearsigned io.Reader, showKeyTip bool) (*KeyInfo, error) {
signedBuffer, err := io.ReadAll(clearsigned)
if err != nil {
return nil, errors.Wrap(err, "failed to read clearsigned data")
}
block, _ := clearsign.Decode(signedBuffer)
if block == nil {
return nil, errors.New("no clearsigned data found")
}
signers, missingKeys, err := checkDetachedSignature(g.trustedKeyring, bytes.NewBuffer(block.Bytes), block.ArmoredSignature.Body)
g.printLog(signers)
if showKeyTip && missingKeys > 0 {
g.showImportKeyTip(signers)
}
if err != nil {
return nil, errors.Wrap(err, "failed to verify signature")
}
result := &KeyInfo{}
for _, signer := range signers {
if signer.Entity != nil {
result.GoodKeys = append(result.GoodKeys, KeyFromUint64(signer.IssuerKeyID))
} else {
result.MissingKeys = append(result.MissingKeys, KeyFromUint64(signer.IssuerKeyID))
}
}
return result, nil
}
// ExtractClearsigned extracts cleartext from clearsigned file WITHOUT signature verification
func (g *GoVerifier) ExtractClearsigned(clearsigned io.Reader) (text *os.File, err error) {
var signedBuffer []byte
signedBuffer, err = io.ReadAll(clearsigned)
if err != nil {
return nil, errors.Wrap(err, "failed to read clearsigned data")
}
block, _ := clearsign.Decode(signedBuffer)
if block == nil {
return nil, errors.New("no clearsigned data found")
}
text, err = os.CreateTemp("", "aptly-gpg")
if err != nil {
return
}
defer os.Remove(text.Name())
_, err = text.Write(block.Bytes)
if err != nil {
return
}
_, err = text.Seek(0, 0)
return
}
var gnupgHome string
func loadKeyRing(name string, ignoreMissing bool) (openpgp.EntityList, error) {
// if path doesn't contain slashes, treat it as relative to GnuPG home directory
if !strings.Contains(name, "/") {
name = filepath.Join(gnupgHome, name)
}
f, err := os.Open(name)
if err != nil {
if os.IsNotExist(err) {
if !ignoreMissing {
fmt.Printf("opengpg: failure opening keyring '%s': %s\n", name, err)
}
return nil, nil
}
return nil, err
}
defer f.Close()
return openpgp.ReadKeyRing(f)
}
func init() {
gnupgHome = os.Getenv("GNUPGHOME")
if gnupgHome == "" {
// use default location
gnupgHome = filepath.Join(os.Getenv("HOME"), ".gnupg")
}
}