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refactor(packet): Integrate changes from review in PKESK
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@lubux
lubux committed Nov 22, 2023
1 parent 1408255 commit c10c41e
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Showing 2 changed files with 44 additions and 27 deletions.
56 changes: 29 additions & 27 deletions openpgp/packet/encrypted_key.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ type EncryptedKey struct {

func (e *EncryptedKey) parse(r io.Reader) (err error) {
var buf [8]byte
_, err = readFull(r, buf[:1])
_, err = readFull(r, buf[:versionSize])
if err != nil {
return
}
Expand All @@ -51,15 +51,14 @@ func (e *EncryptedKey) parse(r io.Reader) (err error) {
}
if e.Version == 6 {
//Read a one-octet size of the following two fields.
_, err = readFull(r, buf[:1])
if err != nil {
if _, err = readFull(r, buf[:1]); err != nil {
return
}
// The size may also be zero, and the key version and
// fingerprint omitted for an "anonymous recipient"
if buf[0] != 0 {
// non-anonymous case
_, err = readFull(r, buf[:1])
_, err = readFull(r, buf[:versionSize])
if err != nil {
return
}
Expand All @@ -69,27 +68,27 @@ func (e *EncryptedKey) parse(r io.Reader) (err error) {
}
var fingerprint []byte
if e.KeyVersion == 6 {
fingerprint = make([]byte, 32)
fingerprint = make([]byte, fingerprintSizeV6)
} else if e.KeyVersion == 4 {
fingerprint = make([]byte, 20)
fingerprint = make([]byte, fingerprintSize)
}
_, err = readFull(r, fingerprint)
if err != nil {
return
}
e.KeyFingerprint = fingerprint
if e.KeyVersion == 6 {
e.KeyId = binary.BigEndian.Uint64(e.KeyFingerprint[:8])
e.KeyId = binary.BigEndian.Uint64(e.KeyFingerprint[:keyIdSize])
} else if e.KeyVersion == 4 {
e.KeyId = binary.BigEndian.Uint64(e.KeyFingerprint[12:20])
e.KeyId = binary.BigEndian.Uint64(e.KeyFingerprint[fingerprintSize-keyIdSize : fingerprintSize])
}
}
} else {
_, err = readFull(r, buf[:8])
if err != nil {
return
}
e.KeyId = binary.BigEndian.Uint64(buf[:8])
e.KeyId = binary.BigEndian.Uint64(buf[:keyIdSize])
}

_, err = readFull(r, buf[:1])
Expand Down Expand Up @@ -206,6 +205,9 @@ func (e *EncryptedKey) Decrypt(priv *PrivateKey, config *Config) error {
}
}
key, err = decodeChecksumKey(b[keyOffset:])
if err != nil {
return err
}
case PubKeyAlgoX25519, PubKeyAlgoX448:
if e.Version < 6 {
switch e.CipherFunc {
Expand All @@ -216,9 +218,8 @@ func (e *EncryptedKey) Decrypt(priv *PrivateKey, config *Config) error {
}
}
key = b[:]
}
if err != nil {
return err
default:
return errors.UnsupportedError("unsupported algorithm for decryption")
}
e.Key = key
return nil
Expand All @@ -242,13 +243,13 @@ func (e *EncryptedKey) Serialize(w io.Writer) error {
return errors.InvalidArgumentError("don't know how to serialize encrypted key type " + strconv.Itoa(int(e.Algo)))
}

packetLen := 1 /* version */ + 8 /* key id */ + 1 /* algo */ + encodedLength
packetLen := versionSize /* version */ + keyIdSize /* key id */ + algorithmSize /* algo */ + encodedLength
if e.Version == 6 {
packetLen = 1 /* version */ + 1 /* algo */ + encodedLength + 1 /* key version */
packetLen = versionSize /* version */ + algorithmSize /* algo */ + encodedLength + keyVersionSize /* key version */
if e.KeyVersion == 6 {
packetLen += 32
packetLen += fingerprintSizeV6
} else if e.KeyVersion == 4 {
packetLen += 20
packetLen += fingerprintSize
}
}

Expand Down Expand Up @@ -313,7 +314,7 @@ func (e *EncryptedKey) Serialize(w io.Writer) error {
}
}

// SerializeEncryptedKey serializes an encrypted key packet to w that contains
// SerializeEncryptedKeyAEAD serializes an encrypted key packet to w that contains
// key, encrypted to pub.
// If aeadSupported is set, PKESK v6 is used else v4.
// If config is nil, sensible defaults will be used.
Expand All @@ -328,7 +329,7 @@ func SerializeEncryptedKeyAEAD(w io.Writer, pub *PublicKey, cipherFunc CipherFun
// If config is nil, sensible defaults will be used.
func SerializeEncryptedKeyAEADwithHiddenOption(w io.Writer, pub *PublicKey, cipherFunc CipherFunction, aeadSupported bool, key []byte, hidden bool, config *Config) error {
var buf [36]byte // max possible header size is v6
lenHeaderWritten := 1
lenHeaderWritten := versionSize
version := 3

if aeadSupported {
Expand Down Expand Up @@ -357,12 +358,13 @@ func SerializeEncryptedKeyAEADwithHiddenOption(w io.Writer, pub *PublicKey, ciph
if version == 6 {
if !hidden {
// A one-octet size of the following two fields.
buf[1] = byte(1 + len(pub.Fingerprint))
buf[1] = byte(keyVersionSize + len(pub.Fingerprint))
// A one octet key version number.
buf[2] = byte(pub.Version)
lenHeaderWritten += keyVersionSize + 1
// The fingerprint of the public key
copy(buf[3:len(pub.Fingerprint)+3], pub.Fingerprint)
lenHeaderWritten += len(pub.Fingerprint) + 2
copy(buf[lenHeaderWritten:lenHeaderWritten+len(pub.Fingerprint)], pub.Fingerprint)
lenHeaderWritten += len(pub.Fingerprint)
} else {
// The size may also be zero, and the key version
// and fingerprint omitted for an "anonymous recipient"
Expand All @@ -371,12 +373,12 @@ func SerializeEncryptedKeyAEADwithHiddenOption(w io.Writer, pub *PublicKey, ciph
}
} else {
if !hidden {
binary.BigEndian.PutUint64(buf[1:9], pub.KeyId)
binary.BigEndian.PutUint64(buf[versionSize:(versionSize+keyIdSize)], pub.KeyId)
}
lenHeaderWritten += 8
lenHeaderWritten += keyIdSize
}
buf[lenHeaderWritten] = byte(pub.PubKeyAlgo)
lenHeaderWritten += 1
lenHeaderWritten += algorithmSize

var keyBlock []byte
switch pub.PubKeyAlgo {
Expand Down Expand Up @@ -423,9 +425,9 @@ func SerializeEncryptedKey(w io.Writer, pub *PublicKey, cipherFunc CipherFunctio
return SerializeEncryptedKeyAEAD(w, pub, cipherFunc, config.AEAD() != nil, key, config)
}

// SerializeEncryptedKey serializes an encrypted key packet to w that contains
// key, encrypted to pub.
// PKESKv6 is used if config.AEAD() is not nil.
// SerializeEncryptedKeyWithHiddenOption serializes an encrypted key packet to w that contains
// key, encrypted to pub. PKESKv6 is used if config.AEAD() is not nil.
// The hidden option controls if the packet should be anonymous, i.e., omit key metadata.
// If config is nil, sensible defaults will be used.
func SerializeEncryptedKeyWithHiddenOption(w io.Writer, pub *PublicKey, cipherFunc CipherFunction, key []byte, hidden bool, config *Config) error {
return SerializeEncryptedKeyAEADwithHiddenOption(w, pub, cipherFunc, config.AEAD() != nil, key, hidden, config)
Expand Down
15 changes: 15 additions & 0 deletions openpgp/packet/packet.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -656,3 +656,18 @@ type TrustLevel uint8

// TrustAmount represents a trust amount per RFC4880 5.2.3.13
type TrustAmount uint8

const (
// versionSize is the length in bytes of the version value.
versionSize = 1
// algorithmSize is the length in bytes of the key algorithm value.
algorithmSize = 1
// keyVersionSize is the length in bytes of the key version value
keyVersionSize = 1
// keyIdSize is the length in bytes of the key identifier value.
keyIdSize = 8
// fingerprintSizeV6 is the length in bytes of the key fingerprint in v6.
fingerprintSizeV6 = 32
// fingerprintSize is the length in bytes of the key fingerprint.
fingerprintSize = 20
)

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