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Unify key generation self-signature (#208)
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- Serialized signature sub-packets are now ordered by their ID.
- The creation time, issuer key ID, and key flag sub-packets are now critical.
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lubux authored Jun 24, 2024
1 parent dc5f72b commit 7f9da72
Showing 1 changed file with 88 additions and 89 deletions.
177 changes: 88 additions & 89 deletions openpgp/packet/signature.go
Original file line number Diff line number Diff line change
Expand Up @@ -1182,28 +1182,68 @@ type outputSubpacket struct {
func (sig *Signature) buildSubpackets(issuer PublicKey) (subpackets []outputSubpacket, err error) {
creationTime := make([]byte, 4)
binary.BigEndian.PutUint32(creationTime, uint32(sig.CreationTime.Unix()))
subpackets = append(subpackets, outputSubpacket{true, creationTimeSubpacket, false, creationTime})

// Signature Creation Time
subpackets = append(subpackets, outputSubpacket{true, creationTimeSubpacket, true, creationTime})
// Signature Expiration Time
if sig.SigLifetimeSecs != nil && *sig.SigLifetimeSecs != 0 {
sigLifetime := make([]byte, 4)
binary.BigEndian.PutUint32(sigLifetime, *sig.SigLifetimeSecs)
subpackets = append(subpackets, outputSubpacket{true, signatureExpirationSubpacket, true, sigLifetime})
}
// Trust Signature
if sig.TrustLevel != 0 {
subpackets = append(subpackets, outputSubpacket{true, trustSubpacket, true, []byte{byte(sig.TrustLevel), byte(sig.TrustAmount)}})
}
// Regular Expression
if sig.TrustRegularExpression != nil {
// RFC specifies the string should be null-terminated; add a null byte to the end
subpackets = append(subpackets, outputSubpacket{true, regularExpressionSubpacket, true, []byte(*sig.TrustRegularExpression + "\000")})
}
// Key Expiration Time
if sig.KeyLifetimeSecs != nil && *sig.KeyLifetimeSecs != 0 {
keyLifetime := make([]byte, 4)
binary.BigEndian.PutUint32(keyLifetime, *sig.KeyLifetimeSecs)
subpackets = append(subpackets, outputSubpacket{true, keyExpirationSubpacket, true, keyLifetime})
}
// Preferred Symmetric Ciphers for v1 SEIPD
if len(sig.PreferredSymmetric) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefSymmetricAlgosSubpacket, false, sig.PreferredSymmetric})
}
// Issuer Key ID
if sig.IssuerKeyId != nil && sig.Version == 4 {
keyId := make([]byte, 8)
binary.BigEndian.PutUint64(keyId, *sig.IssuerKeyId)
subpackets = append(subpackets, outputSubpacket{true, issuerSubpacket, false, keyId})
subpackets = append(subpackets, outputSubpacket{true, issuerSubpacket, true, keyId})
}
if sig.IssuerFingerprint != nil {
contents := append([]uint8{uint8(issuer.Version)}, sig.IssuerFingerprint...)
subpackets = append(subpackets, outputSubpacket{true, issuerFingerprintSubpacket, sig.Version >= 5, contents})
// Notation Data
for _, notation := range sig.Notations {
subpackets = append(
subpackets,
outputSubpacket{
true,
notationDataSubpacket,
notation.IsCritical,
notation.getData(),
})
}
if sig.SignerUserId != nil {
subpackets = append(subpackets, outputSubpacket{true, signerUserIdSubpacket, false, []byte(*sig.SignerUserId)})
// Preferred Hash Algorithms
if len(sig.PreferredHash) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefHashAlgosSubpacket, false, sig.PreferredHash})
}
if sig.SigLifetimeSecs != nil && *sig.SigLifetimeSecs != 0 {
sigLifetime := make([]byte, 4)
binary.BigEndian.PutUint32(sigLifetime, *sig.SigLifetimeSecs)
subpackets = append(subpackets, outputSubpacket{true, signatureExpirationSubpacket, true, sigLifetime})
// Preferred Compression Algorithms
if len(sig.PreferredCompression) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefCompressionSubpacket, false, sig.PreferredCompression})
}

// Primary User ID
if sig.IsPrimaryId != nil && *sig.IsPrimaryId {
subpackets = append(subpackets, outputSubpacket{true, primaryUserIdSubpacket, false, []byte{1}})
}
// Policy URI
if len(sig.PolicyURI) > 0 {
subpackets = append(subpackets, outputSubpacket{true, policyUriSubpacket, false, []uint8(sig.PolicyURI)})
}
// Key Flags
// Key flags may only appear in self-signatures or certification signatures.

if sig.FlagsValid {
var flags byte
if sig.FlagCertify {
Expand All @@ -1227,80 +1267,56 @@ func (sig *Signature) buildSubpackets(issuer PublicKey) (subpackets []outputSubp
if sig.FlagGroupKey {
flags |= KeyFlagGroupKey
}
subpackets = append(subpackets, outputSubpacket{true, keyFlagsSubpacket, false, []byte{flags}})
subpackets = append(subpackets, outputSubpacket{true, keyFlagsSubpacket, true, []byte{flags}})
}

for _, notation := range sig.Notations {
subpackets = append(
subpackets,
outputSubpacket{
true,
notationDataSubpacket,
notation.IsCritical,
notation.getData(),
})
// Signer's User ID
if sig.SignerUserId != nil {
subpackets = append(subpackets, outputSubpacket{true, signerUserIdSubpacket, false, []byte(*sig.SignerUserId)})
}

for _, recipient := range sig.IntendedRecipients {
subpackets = append(
subpackets,
outputSubpacket{
true,
intendedRecipientSubpacket,
false,
recipient.Serialize(),
})
// Reason for Revocation
// Revocation reason appears only in revocation signatures and is serialized as per section 5.2.3.23.
if sig.RevocationReason != nil {
subpackets = append(subpackets, outputSubpacket{true, reasonForRevocationSubpacket, true,
append([]uint8{uint8(*sig.RevocationReason)}, []uint8(sig.RevocationReasonText)...)})
}

// The following subpackets may only appear in self-signatures.

// Features
var features = byte(0x00)
if sig.SEIPDv1 {
features |= 0x01
}
if sig.SEIPDv2 {
features |= 0x08
}

if features != 0x00 {
subpackets = append(subpackets, outputSubpacket{true, featuresSubpacket, false, []byte{features}})
}

if sig.TrustLevel != 0 {
subpackets = append(subpackets, outputSubpacket{true, trustSubpacket, true, []byte{byte(sig.TrustLevel), byte(sig.TrustAmount)}})
}

if sig.TrustRegularExpression != nil {
// RFC specifies the string should be null-terminated; add a null byte to the end
subpackets = append(subpackets, outputSubpacket{true, regularExpressionSubpacket, true, []byte(*sig.TrustRegularExpression + "\000")})
}

if sig.KeyLifetimeSecs != nil && *sig.KeyLifetimeSecs != 0 {
keyLifetime := make([]byte, 4)
binary.BigEndian.PutUint32(keyLifetime, *sig.KeyLifetimeSecs)
subpackets = append(subpackets, outputSubpacket{true, keyExpirationSubpacket, true, keyLifetime})
}

if sig.IsPrimaryId != nil && *sig.IsPrimaryId {
subpackets = append(subpackets, outputSubpacket{true, primaryUserIdSubpacket, false, []byte{1}})
}

if len(sig.PreferredSymmetric) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefSymmetricAlgosSubpacket, false, sig.PreferredSymmetric})
}

if len(sig.PreferredHash) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefHashAlgosSubpacket, false, sig.PreferredHash})
// Embedded Signature
// EmbeddedSignature appears only in subkeys capable of signing and is serialized as per section 5.2.3.26.
if sig.EmbeddedSignature != nil {
var buf bytes.Buffer
err = sig.EmbeddedSignature.serializeBody(&buf)
if err != nil {
return
}
subpackets = append(subpackets, outputSubpacket{true, embeddedSignatureSubpacket, true, buf.Bytes()})
}

if len(sig.PreferredCompression) > 0 {
subpackets = append(subpackets, outputSubpacket{true, prefCompressionSubpacket, false, sig.PreferredCompression})
// Issuer Fingerprint
if sig.IssuerFingerprint != nil {
contents := append([]uint8{uint8(issuer.Version)}, sig.IssuerFingerprint...)
subpackets = append(subpackets, outputSubpacket{true, issuerFingerprintSubpacket, sig.Version >= 5, contents})
}

if len(sig.PolicyURI) > 0 {
subpackets = append(subpackets, outputSubpacket{true, policyUriSubpacket, false, []uint8(sig.PolicyURI)})
// Intended Recipient Fingerprint
for _, recipient := range sig.IntendedRecipients {
subpackets = append(
subpackets,
outputSubpacket{
true,
intendedRecipientSubpacket,
false,
recipient.Serialize(),
})
}

// Preferred AEAD Ciphersuites
if len(sig.PreferredCipherSuites) > 0 {
serialized := make([]byte, len(sig.PreferredCipherSuites)*2)
for i, cipherSuite := range sig.PreferredCipherSuites {
Expand All @@ -1309,23 +1325,6 @@ func (sig *Signature) buildSubpackets(issuer PublicKey) (subpackets []outputSubp
}
subpackets = append(subpackets, outputSubpacket{true, prefCipherSuitesSubpacket, false, serialized})
}

// Revocation reason appears only in revocation signatures and is serialized as per section 5.2.3.23.
if sig.RevocationReason != nil {
subpackets = append(subpackets, outputSubpacket{true, reasonForRevocationSubpacket, true,
append([]uint8{uint8(*sig.RevocationReason)}, []uint8(sig.RevocationReasonText)...)})
}

// EmbeddedSignature appears only in subkeys capable of signing and is serialized as per section 5.2.3.26.
if sig.EmbeddedSignature != nil {
var buf bytes.Buffer
err = sig.EmbeddedSignature.serializeBody(&buf)
if err != nil {
return
}
subpackets = append(subpackets, outputSubpacket{true, embeddedSignatureSubpacket, true, buf.Bytes()})
}

return
}

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