// Copyright 2011 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package openpgp import ( "crypto/hmac" "encoding/binary" "io" "time" "github.com/keybase/go-crypto/openpgp/armor" "github.com/keybase/go-crypto/openpgp/errors" "github.com/keybase/go-crypto/openpgp/packet" "github.com/keybase/go-crypto/rsa" ) // PublicKeyType is the armor type for a PGP public key. var PublicKeyType = "PGP PUBLIC KEY BLOCK" // PrivateKeyType is the armor type for a PGP private key. var PrivateKeyType = "PGP PRIVATE KEY BLOCK" // An Entity represents the components of an OpenPGP key: a primary public key // (which must be a signing key), one or more identities claimed by that key, // and zero or more subkeys, which may be encryption keys. type Entity struct { PrimaryKey *packet.PublicKey PrivateKey *packet.PrivateKey Identities map[string]*Identity // indexed by Identity.Name Revocations []*packet.Signature // Revocations that are signed by designated revokers. Reading keys // will not verify these revocations, because it won't have access to // issuers' public keys, API consumers should do this instead (or // not, and just assume that the key is probably revoked). UnverifiedRevocations []*packet.Signature Subkeys []Subkey BadSubkeys []BadSubkey } // An Identity represents an identity claimed by an Entity and zero or more // assertions by other entities about that claim. type Identity struct { Name string // by convention, has the form "Full Name (comment) <email@example.com>" UserId *packet.UserId SelfSignature *packet.Signature Signatures []*packet.Signature Revocation *packet.Signature } // A Subkey is an additional public key in an Entity. Subkeys can be used for // encryption. type Subkey struct { PublicKey *packet.PublicKey PrivateKey *packet.PrivateKey Sig *packet.Signature Revocation *packet.Signature } // BadSubkey is one that failed reconstruction, but we'll keep it around for // informational purposes. type BadSubkey struct { Subkey Err error } // A Key identifies a specific public key in an Entity. This is either the // Entity's primary key or a subkey. type Key struct { Entity *Entity PublicKey *packet.PublicKey PrivateKey *packet.PrivateKey SelfSignature *packet.Signature KeyFlags packet.KeyFlagBits } // A KeyRing provides access to public and private keys. type KeyRing interface { // KeysById returns the set of keys that have the given key id. // fp can be optionally supplied, which is the full key fingerprint. // If it's provided, then it must match. This comes up in the case // of GPG subpacket 33. KeysById(id uint64, fp []byte) []Key // KeysByIdAndUsage returns the set of keys with the given id // that also meet the key usage given by requiredUsage. // The requiredUsage is expressed as the bitwise-OR of // packet.KeyFlag* values. // fp can be optionally supplied, which is the full key fingerprint. // If it's provided, then it must match. This comes up in the case // of GPG subpacket 33. KeysByIdUsage(id uint64, fp []byte, requiredUsage byte) []Key // DecryptionKeys returns all private keys that are valid for // decryption. DecryptionKeys() []Key } // primaryIdentity returns the Identity marked as primary or the first identity // if none are so marked. func (e *Entity) primaryIdentity() *Identity { var firstIdentity *Identity for _, ident := range e.Identities { if firstIdentity == nil { firstIdentity = ident } if ident.SelfSignature.IsPrimaryId != nil && *ident.SelfSignature.IsPrimaryId { return ident } } return firstIdentity } // encryptionKey returns the best candidate Key for encrypting a message to the // given Entity. func (e *Entity) encryptionKey(now time.Time) (Key, bool) { candidateSubkey := -1 // Iterate the keys to find the newest key var maxTime time.Time for i, subkey := range e.Subkeys { // NOTE(maxtaco) // If there is a Flags subpacket, then we have to follow it, and only // use keys that are marked for Encryption of Communication. If there // isn't a Flags subpacket, and this is an Encrypt-Only key (right now only ElGamal // suffices), then we implicitly use it. The check for primary below is a little // more open-ended, but for now, let's be strict and potentially open up // if we see bugs in the wild. // // One more note: old DSA/ElGamal keys tend not to have the Flags subpacket, // so this sort of thing is pretty important for encrypting to older keys. // if ((subkey.Sig.FlagsValid && subkey.Sig.FlagEncryptCommunications) || (!subkey.Sig.FlagsValid && subkey.PublicKey.PubKeyAlgo == packet.PubKeyAlgoElGamal)) && subkey.PublicKey.PubKeyAlgo.CanEncrypt() && !subkey.Sig.KeyExpired(now) && subkey.Revocation == nil && (maxTime.IsZero() || subkey.Sig.CreationTime.After(maxTime)) { candidateSubkey = i maxTime = subkey.Sig.CreationTime } } if candidateSubkey != -1 { subkey := e.Subkeys[candidateSubkey] return Key{e, subkey.PublicKey, subkey.PrivateKey, subkey.Sig, subkey.Sig.GetKeyFlags()}, true } // If we don't have any candidate subkeys for encryption and // the primary key doesn't have any usage metadata then we // assume that the primary key is ok. Or, if the primary key is // marked as ok to encrypt to, then we can obviously use it. // // NOTE(maxtaco) - see note above, how this policy is a little too open-ended // for my liking, but leave it for now. i := e.primaryIdentity() if (!i.SelfSignature.FlagsValid || i.SelfSignature.FlagEncryptCommunications) && e.PrimaryKey.PubKeyAlgo.CanEncrypt() && !i.SelfSignature.KeyExpired(now) { return Key{e, e.PrimaryKey, e.PrivateKey, i.SelfSignature, i.SelfSignature.GetKeyFlags()}, true } // This Entity appears to be signing only. return Key{}, false } // signingKey return the best candidate Key for signing a message with this // Entity. func (e *Entity) signingKey(now time.Time) (Key, bool) { candidateSubkey := -1 for i, subkey := range e.Subkeys { if (!subkey.Sig.FlagsValid || subkey.Sig.FlagSign) && subkey.PrivateKey.PrivateKey != nil && subkey.PublicKey.PubKeyAlgo.CanSign() && subkey.Revocation == nil && !subkey.Sig.KeyExpired(now) { candidateSubkey = i break } } if candidateSubkey != -1 { subkey := e.Subkeys[candidateSubkey] return Key{e, subkey.PublicKey, subkey.PrivateKey, subkey.Sig, subkey.Sig.GetKeyFlags()}, true } // If we have no candidate subkey then we assume that it's ok to sign // with the primary key. i := e.primaryIdentity() if (!i.SelfSignature.FlagsValid || i.SelfSignature.FlagSign) && e.PrimaryKey.PubKeyAlgo.CanSign() && !i.SelfSignature.KeyExpired(now) && e.PrivateKey.PrivateKey != nil { return Key{e, e.PrimaryKey, e.PrivateKey, i.SelfSignature, i.SelfSignature.GetKeyFlags()}, true } return Key{}, false } // An EntityList contains one or more Entities. type EntityList []*Entity func keyMatchesIdAndFingerprint(key *packet.PublicKey, id uint64, fp []byte) bool { if key.KeyId != id { return false } if fp == nil { return true } return hmac.Equal(fp, key.Fingerprint[:]) } // KeysById returns the set of keys that have the given key id. // fp can be optionally supplied, which is the full key fingerprint. // If it's provided, then it must match. This comes up in the case // of GPG subpacket 33. func (el EntityList) KeysById(id uint64, fp []byte) (keys []Key) { for _, e := range el { if keyMatchesIdAndFingerprint(e.PrimaryKey, id, fp) { var selfSig *packet.Signature for _, ident := range e.Identities { if selfSig == nil { selfSig = ident.SelfSignature } else if ident.SelfSignature.IsPrimaryId != nil && *ident.SelfSignature.IsPrimaryId { selfSig = ident.SelfSignature break } } var keyFlags packet.KeyFlagBits for _, ident := range e.Identities { keyFlags.Merge(ident.SelfSignature.GetKeyFlags()) } keys = append(keys, Key{e, e.PrimaryKey, e.PrivateKey, selfSig, keyFlags}) } for _, subKey := range e.Subkeys { if keyMatchesIdAndFingerprint(subKey.PublicKey, id, fp) { // If there's both a a revocation and a sig, then take the // revocation. Otherwise, we can proceed with the sig. sig := subKey.Revocation if sig == nil { sig = subKey.Sig } keys = append(keys, Key{e, subKey.PublicKey, subKey.PrivateKey, sig, sig.GetKeyFlags()}) } } } return } // KeysByIdAndUsage returns the set of keys with the given id that also meet // the key usage given by requiredUsage. The requiredUsage is expressed as // the bitwise-OR of packet.KeyFlag* values. // fp can be optionally supplied, which is the full key fingerprint. // If it's provided, then it must match. This comes up in the case // of GPG subpacket 33. func (el EntityList) KeysByIdUsage(id uint64, fp []byte, requiredUsage byte) (keys []Key) { for _, key := range el.KeysById(id, fp) { if len(key.Entity.Revocations) > 0 { continue } if key.SelfSignature.RevocationReason != nil { continue } if requiredUsage != 0 { var usage byte switch { case key.KeyFlags.Valid: usage = key.KeyFlags.BitField case key.PublicKey.PubKeyAlgo == packet.PubKeyAlgoElGamal: // We also need to handle the case where, although the sig's // flags aren't valid, the key can is implicitly usable for // encryption by virtue of being ElGamal. See also the comment // in encryptionKey() above. usage |= packet.KeyFlagEncryptCommunications usage |= packet.KeyFlagEncryptStorage case key.PublicKey.PubKeyAlgo == packet.PubKeyAlgoDSA || key.PublicKey.PubKeyAlgo == packet.PubKeyAlgoECDSA || key.PublicKey.PubKeyAlgo == packet.PubKeyAlgoEdDSA: usage |= packet.KeyFlagSign // For a primary RSA key without any key flags, be as permissiable // as possible. case key.PublicKey.PubKeyAlgo == packet.PubKeyAlgoRSA && keyMatchesIdAndFingerprint(key.Entity.PrimaryKey, id, fp): usage = (packet.KeyFlagCertify | packet.KeyFlagSign | packet.KeyFlagEncryptCommunications | packet.KeyFlagEncryptStorage) } if usage&requiredUsage != requiredUsage { continue } } keys = append(keys, key) } return } // DecryptionKeys returns all private keys that are valid for decryption. func (el EntityList) DecryptionKeys() (keys []Key) { for _, e := range el { for _, subKey := range e.Subkeys { if subKey.PrivateKey != nil && subKey.PrivateKey.PrivateKey != nil && (!subKey.Sig.FlagsValid || subKey.Sig.FlagEncryptStorage || subKey.Sig.FlagEncryptCommunications) { keys = append(keys, Key{e, subKey.PublicKey, subKey.PrivateKey, subKey.Sig, subKey.Sig.GetKeyFlags()}) } } } return } // ReadArmoredKeyRing reads one or more public/private keys from an armor keyring file. func ReadArmoredKeyRing(r io.Reader) (EntityList, error) { block, err := armor.Decode(r) if err == io.EOF { return nil, errors.InvalidArgumentError("no armored data found") } if err != nil { return nil, err } if block.Type != PublicKeyType && block.Type != PrivateKeyType { return nil, errors.InvalidArgumentError("expected public or private key block, got: " + block.Type) } return ReadKeyRing(block.Body) } // ReadKeyRing reads one or more public/private keys. Unsupported keys are // ignored as long as at least a single valid key is found. func ReadKeyRing(r io.Reader) (el EntityList, err error) { packets := packet.NewReader(r) var lastUnsupportedError error for { var e *Entity e, err = ReadEntity(packets) if err != nil { // TODO: warn about skipped unsupported/unreadable keys if _, ok := err.(errors.UnsupportedError); ok { lastUnsupportedError = err err = readToNextPublicKey(packets) } else if _, ok := err.(errors.StructuralError); ok { // Skip unreadable, badly-formatted keys lastUnsupportedError = err err = readToNextPublicKey(packets) } if err == io.EOF { err = nil break } if err != nil { el = nil break } } else { el = append(el, e) } } if len(el) == 0 && err == nil { err = lastUnsupportedError } return } // readToNextPublicKey reads packets until the start of the entity and leaves // the first packet of the new entity in the Reader. func readToNextPublicKey(packets *packet.Reader) (err error) { var p packet.Packet for { p, err = packets.Next() if err == io.EOF { return } else if err != nil { if _, ok := err.(errors.UnsupportedError); ok { err = nil continue } return } if pk, ok := p.(*packet.PublicKey); ok && !pk.IsSubkey { packets.Unread(p) return } } panic("unreachable") } // ReadEntity reads an entity (public key, identities, subkeys etc) from the // given Reader. func ReadEntity(packets *packet.Reader) (*Entity, error) { e := new(Entity) e.Identities = make(map[string]*Identity) p, err := packets.Next() if err != nil { return nil, err } var ok bool if e.PrimaryKey, ok = p.(*packet.PublicKey); !ok { if e.PrivateKey, ok = p.(*packet.PrivateKey); !ok { packets.Unread(p) return nil, errors.StructuralError("first packet was not a public/private key") } else { e.PrimaryKey = &e.PrivateKey.PublicKey } } if !e.PrimaryKey.PubKeyAlgo.CanSign() { return nil, errors.StructuralError("primary key cannot be used for signatures") } var current *Identity var revocations []*packet.Signature designatedRevokers := make(map[uint64]bool) EachPacket: for { p, err := packets.Next() if err == io.EOF { break } else if err != nil { return nil, err } switch pkt := p.(type) { case *packet.UserId: // Make a new Identity object, that we might wind up throwing away. // We'll only add it if we get a valid self-signature over this // userID. current = new(Identity) current.Name = pkt.Id current.UserId = pkt case *packet.Signature: if pkt.SigType == packet.SigTypeKeyRevocation { // These revocations won't revoke UIDs (see // SigTypeIdentityRevocation). Handle these first, // because key might have revocation coming from // another key (designated revoke). revocations = append(revocations, pkt) continue } // These are signatures by other people on this key. Let's just ignore them // from the beginning, since they shouldn't affect our key decoding one way // or the other. if pkt.IssuerKeyId != nil && *pkt.IssuerKeyId != e.PrimaryKey.KeyId { continue } // If this is a signature made by the keyholder, and the signature has stubbed out // critical packets, then *now* we need to bail out. if e := pkt.StubbedOutCriticalError; e != nil { return nil, e } // Next handle the case of a self-signature. According to RFC8440, // Section 5.2.3.3, if there are several self-signatures, // we should take the newer one. If they were both created // at the same time, but one of them has keyflags specified and the // other doesn't, keep the one with the keyflags. We have actually // seen this in the wild (see the 'Yield' test in read_test.go). // If there is a tie, and both have the same value for FlagsValid, // then "last writer wins." // // HOWEVER! We have seen yet more keys in the wild (see the 'Spiros' // test in read_test.go), in which the later self-signature is a bunch // of junk, and doesn't even specify key flags. Does it really make // sense to overwrite reasonable key flags with the empty set? I'm not // sure what that would be trying to achieve, and plus GPG seems to be // ok with this situation, and ignores the later (empty) keyflag set. // So further tighten our overwrite rules, and only allow the later // signature to overwrite the earlier signature if so doing won't // trash the key flags. if current != nil && (current.SelfSignature == nil || (!pkt.CreationTime.Before(current.SelfSignature.CreationTime) && (pkt.FlagsValid || !current.SelfSignature.FlagsValid))) && (pkt.SigType == packet.SigTypePositiveCert || pkt.SigType == packet.SigTypeGenericCert) && pkt.IssuerKeyId != nil && *pkt.IssuerKeyId == e.PrimaryKey.KeyId { if err = e.PrimaryKey.VerifyUserIdSignature(current.Name, e.PrimaryKey, pkt); err == nil { current.SelfSignature = pkt // NOTE(maxtaco) 2016.01.11 // Only register an identity once we've gotten a valid self-signature. // It's possible therefore for us to throw away `current` in the case // no valid self-signatures were found. That's OK as long as there are // other identies that make sense. // // NOTE! We might later see a revocation for this very same UID, and it // won't be undone. We've preserved this feature from the original // Google OpenPGP we forked from. e.Identities[current.Name] = current } else { // We really should warn that there was a failure here. Not raise an error // since this really shouldn't be a fail-stop error. } } else if current != nil && pkt.SigType == packet.SigTypeIdentityRevocation { if err = e.PrimaryKey.VerifyUserIdSignature(current.Name, e.PrimaryKey, pkt); err == nil { // Note: we are not removing the identity from // e.Identities. Caller can always filter by Revocation // field to ignore revoked identities. current.Revocation = pkt } } else if pkt.SigType == packet.SigTypeDirectSignature { if err = e.PrimaryKey.VerifyRevocationSignature(e.PrimaryKey, pkt); err == nil { if desig := pkt.DesignatedRevoker; desig != nil { // If it's a designated revoker signature, take last 8 octects // of fingerprint as Key ID and save it to designatedRevokers // map. We consult this map later to see if a foreign // revocation should be added to UnverifiedRevocations. keyID := binary.BigEndian.Uint64(desig.Fingerprint[len(desig.Fingerprint)-8:]) designatedRevokers[keyID] = true } } } else if current == nil { // NOTE(maxtaco) // // See https://github.com/keybase/client/issues/2666 // // There might have been a user attribute picture before this signature, // in which case this is still a valid PGP key. In the future we might // not ignore user attributes (like picture). But either way, it doesn't // make sense to bail out here. Keep looking for other valid signatures. // // Used to be: // return nil, errors.StructuralError("signature packet found before user id packet") } else { current.Signatures = append(current.Signatures, pkt) } case *packet.PrivateKey: if pkt.IsSubkey == false { packets.Unread(p) break EachPacket } err = addSubkey(e, packets, &pkt.PublicKey, pkt) if err != nil { return nil, err } case *packet.PublicKey: if pkt.IsSubkey == false { packets.Unread(p) break EachPacket } err = addSubkey(e, packets, pkt, nil) if err != nil { return nil, err } default: // we ignore unknown packets } } if len(e.Identities) == 0 { return nil, errors.StructuralError("entity without any identities") } for _, revocation := range revocations { if revocation.IssuerKeyId == nil || *revocation.IssuerKeyId == e.PrimaryKey.KeyId { // Key revokes itself, something that we can verify. err = e.PrimaryKey.VerifyRevocationSignature(e.PrimaryKey, revocation) if err == nil { e.Revocations = append(e.Revocations, revocation) } else { return nil, errors.StructuralError("revocation signature signed by alternate key") } } else if revocation.IssuerKeyId != nil { if _, ok := designatedRevokers[*revocation.IssuerKeyId]; ok { // Revocation is done by certified designated revoker, // but we can't verify the revocation. e.UnverifiedRevocations = append(e.UnverifiedRevocations, revocation) } } } return e, nil } func addSubkey(e *Entity, packets *packet.Reader, pub *packet.PublicKey, priv *packet.PrivateKey) error { var subKey Subkey subKey.PublicKey = pub subKey.PrivateKey = priv var lastErr error for { p, err := packets.Next() if err == io.EOF { break } if err != nil { return errors.StructuralError("subkey signature invalid: " + err.Error()) } sig, ok := p.(*packet.Signature) if !ok { // Hit a non-signature packet, so assume we're up to the next key packets.Unread(p) break } if st := sig.SigType; st != packet.SigTypeSubkeyBinding && st != packet.SigTypeSubkeyRevocation { // Note(maxtaco): // We used to error out here, but instead, let's fast-forward past // packets that are in the wrong place (like misplaced 0x13 signatures) // until we get to one that works. For a test case, // see TestWithBadSubkeySignaturePackets. continue } err = e.PrimaryKey.VerifyKeySignature(subKey.PublicKey, sig) if err != nil { // Non valid signature, so again, no need to abandon all hope, just continue; // make a note of the error we hit. lastErr = errors.StructuralError("subkey signature invalid: " + err.Error()) continue } switch sig.SigType { case packet.SigTypeSubkeyBinding: // Does the "new" sig set expiration to later date than // "previous" sig? if subKey.Sig == nil || subKey.Sig.ExpiresBeforeOther(sig) { subKey.Sig = sig } case packet.SigTypeSubkeyRevocation: // First writer wins if subKey.Revocation == nil { subKey.Revocation = sig } } } if subKey.Sig != nil { e.Subkeys = append(e.Subkeys, subKey) } else { if lastErr == nil { lastErr = errors.StructuralError("Subkey wasn't signed; expected a 'binding' signature") } e.BadSubkeys = append(e.BadSubkeys, BadSubkey{Subkey: subKey, Err: lastErr}) } return nil } const defaultRSAKeyBits = 2048 // NewEntity returns an Entity that contains a fresh RSA/RSA keypair with a // single identity composed of the given full name, comment and email, any of // which may be empty but must not contain any of "()<>\x00". // If config is nil, sensible defaults will be used. func NewEntity(name, comment, email string, config *packet.Config) (*Entity, error) { currentTime := config.Now() bits := defaultRSAKeyBits if config != nil && config.RSABits != 0 { bits = config.RSABits } uid := packet.NewUserId(name, comment, email) if uid == nil { return nil, errors.InvalidArgumentError("user id field contained invalid characters") } signingPriv, err := rsa.GenerateKey(config.Random(), bits) if err != nil { return nil, err } encryptingPriv, err := rsa.GenerateKey(config.Random(), bits) if err != nil { return nil, err } e := &Entity{ PrimaryKey: packet.NewRSAPublicKey(currentTime, &signingPriv.PublicKey), PrivateKey: packet.NewRSAPrivateKey(currentTime, signingPriv), Identities: make(map[string]*Identity), } isPrimaryId := true e.Identities[uid.Id] = &Identity{ Name: uid.Name, UserId: uid, SelfSignature: &packet.Signature{ CreationTime: currentTime, SigType: packet.SigTypePositiveCert, PubKeyAlgo: packet.PubKeyAlgoRSA, Hash: config.Hash(), IsPrimaryId: &isPrimaryId, FlagsValid: true, FlagSign: true, FlagCertify: true, IssuerKeyId: &e.PrimaryKey.KeyId, }, } e.Subkeys = make([]Subkey, 1) e.Subkeys[0] = Subkey{ PublicKey: packet.NewRSAPublicKey(currentTime, &encryptingPriv.PublicKey), PrivateKey: packet.NewRSAPrivateKey(currentTime, encryptingPriv), Sig: &packet.Signature{ CreationTime: currentTime, SigType: packet.SigTypeSubkeyBinding, PubKeyAlgo: packet.PubKeyAlgoRSA, Hash: config.Hash(), FlagsValid: true, FlagEncryptStorage: true, FlagEncryptCommunications: true, IssuerKeyId: &e.PrimaryKey.KeyId, }, } e.Subkeys[0].PublicKey.IsSubkey = true e.Subkeys[0].PrivateKey.IsSubkey = true return e, nil } // SerializePrivate serializes an Entity, including private key material, to // the given Writer. For now, it must only be used on an Entity returned from // NewEntity. // If config is nil, sensible defaults will be used. func (e *Entity) SerializePrivate(w io.Writer, config *packet.Config) (err error) { err = e.PrivateKey.Serialize(w) if err != nil { return } for _, ident := range e.Identities { err = ident.UserId.Serialize(w) if err != nil { return } if e.PrivateKey.PrivateKey != nil { err = ident.SelfSignature.SignUserId(ident.UserId.Id, e.PrimaryKey, e.PrivateKey, config) if err != nil { return } } err = ident.SelfSignature.Serialize(w) if err != nil { return } } for _, subkey := range e.Subkeys { err = subkey.PrivateKey.Serialize(w) if err != nil { return } // Workaround shortcoming of SignKey(), which doesn't work to reverse-sign // sub-signing keys. So if requested, just reuse the signatures already // available to us (if we read this key from a keyring). if e.PrivateKey.PrivateKey != nil && !config.ReuseSignatures() { err = subkey.Sig.SignKey(subkey.PublicKey, e.PrivateKey, config) if err != nil { return } } if subkey.Revocation != nil { err = subkey.Revocation.Serialize(w) if err != nil { return } } err = subkey.Sig.Serialize(w) if err != nil { return } } return nil } // Serialize writes the public part of the given Entity to w. (No private // key material will be output). func (e *Entity) Serialize(w io.Writer) error { err := e.PrimaryKey.Serialize(w) if err != nil { return err } for _, ident := range e.Identities { err = ident.UserId.Serialize(w) if err != nil { return err } err = ident.SelfSignature.Serialize(w) if err != nil { return err } for _, sig := range ident.Signatures { err = sig.Serialize(w) if err != nil { return err } } } for _, subkey := range e.Subkeys { err = subkey.PublicKey.Serialize(w) if err != nil { return err } if subkey.Revocation != nil { err = subkey.Revocation.Serialize(w) if err != nil { return err } } err = subkey.Sig.Serialize(w) if err != nil { return err } } return nil } // SignIdentity adds a signature to e, from signer, attesting that identity is // associated with e. The provided identity must already be an element of // e.Identities and the private key of signer must have been decrypted if // necessary. // If config is nil, sensible defaults will be used. func (e *Entity) SignIdentity(identity string, signer *Entity, config *packet.Config) error { if signer.PrivateKey == nil { return errors.InvalidArgumentError("signing Entity must have a private key") } if signer.PrivateKey.Encrypted { return errors.InvalidArgumentError("signing Entity's private key must be decrypted") } ident, ok := e.Identities[identity] if !ok { return errors.InvalidArgumentError("given identity string not found in Entity") } sig := &packet.Signature{ SigType: packet.SigTypeGenericCert, PubKeyAlgo: signer.PrivateKey.PubKeyAlgo, Hash: config.Hash(), CreationTime: config.Now(), IssuerKeyId: &signer.PrivateKey.KeyId, } if err := sig.SignUserId(identity, e.PrimaryKey, signer.PrivateKey, config); err != nil { return err } ident.Signatures = append(ident.Signatures, sig) return nil } // CopySubkeyRevocations copies subkey revocations from the src Entity over // to the receiver entity. We need this because `gpg --export-secret-key` does // not appear to output subkey revocations. In this case we need to manually // merge with the output of `gpg --export`. func (e *Entity) CopySubkeyRevocations(src *Entity) { m := make(map[[20]byte]*packet.Signature) for _, subkey := range src.Subkeys { if subkey.Revocation != nil { m[subkey.PublicKey.Fingerprint] = subkey.Revocation } } for i, subkey := range e.Subkeys { if r := m[subkey.PublicKey.Fingerprint]; r != nil { e.Subkeys[i].Revocation = r } } } // CheckDesignatedRevokers will try to confirm any of designated // revocation of entity. For this function to work, revocation // issuer's key should be found in keyring. First successfully // verified designated revocation is returned along with the key that // verified it. func FindVerifiedDesignatedRevoke(keyring KeyRing, entity *Entity) (*packet.Signature, *Key) { for _, sig := range entity.UnverifiedRevocations { if sig.IssuerKeyId == nil { continue } issuerKeyId := *sig.IssuerKeyId issuerFingerprint := sig.IssuerFingerprint keys := keyring.KeysByIdUsage(issuerKeyId, issuerFingerprint, packet.KeyFlagSign) if len(keys) == 0 { continue } for _, key := range keys { err := key.PublicKey.VerifyRevocationSignature(entity.PrimaryKey, sig) if err == nil { return sig, &key } } } return nil, nil }