func (vr *VerifyRequest) VerifySignature() bool {
armorData := reArmor(vr.CamliSig)
block, _ := armor.Decode(bytes.NewBufferString(armorData))
if block == nil {
return vr.fail("can't parse camliSig armor")
}
var p packet.Packet
var err os.Error
p, err = packet.Read(block.Body)
if err != nil {
return vr.fail("error reading PGP packet from camliSig: " + err.String())
}
sig, ok := p.(*packet.Signature)
if !ok {
return vr.fail("PGP packet isn't a signature packet")
}
if sig.Hash != crypto.SHA1 && sig.Hash != crypto.SHA256 {
return vr.fail("I can only verify SHA1 or SHA256 signatures")
}
if sig.SigType != packet.SigTypeBinary {
return vr.fail("I can only verify binary signatures")
}
hash := sig.Hash.New()
hash.Write(vr.bp) // payload bytes
err = vr.PublicKeyPacket.VerifySignature(hash, sig)
if err != nil {
return vr.fail(fmt.Sprintf("bad signature: %s", err))
}
vr.SignerKeyId = vr.PublicKeyPacket.KeyIdString()
return true
}
// CheckDetachedSignature takes a signed file and a detached signature and
// returns the signer if the signature is valid. If the signer isn't know,
// UnknownIssuerError is returned.
func CheckDetachedSignature(keyring KeyRing, signed, signature io.Reader) (signer *Entity, err os.Error) {
p, err := packet.Read(signature)
if err != nil {
return
}
sig, ok := p.(*packet.Signature)
if !ok {
return nil, error.StructuralError("non signature packet found")
}
if sig.IssuerKeyId == nil {
return nil, error.StructuralError("signature doesn't have an issuer")
}
keys := keyring.KeysById(*sig.IssuerKeyId)
if len(keys) == 0 {
return nil, error.UnknownIssuerError
}
h, wrappedHash, err := hashForSignature(sig.Hash, sig.SigType)
if err != nil {
return
}
_, err = io.Copy(wrappedHash, signed)
if err != nil && err != os.EOF {
return
}
for _, key := range keys {
if key.SelfSignature.FlagsValid && !key.SelfSignature.FlagSign {
continue
}
err = key.PublicKey.VerifySignature(h, sig)
if err == nil {
return key.Entity, nil
}
}
if err != nil {
return
}
return nil, error.UnknownIssuerError
}
func openArmoredPublicKeyFile(reader io.ReadCloser) (*packet.PublicKey, os.Error) {
defer reader.Close()
var lr = io.LimitReader(reader, publicKeyMaxSize)
block, _ := armor.Decode(lr)
if block == nil {
return nil, os.NewError("Couldn't find PGP block in public key file")
}
if block.Type != "PGP PUBLIC KEY BLOCK" {
return nil, os.NewError("Invalid public key blob.")
}
p, err := packet.Read(block.Body)
if err != nil {
return nil, os.NewError(fmt.Sprintf("Invalid public key blob: %v", err))
}
pk, ok := p.(*packet.PublicKey)
if !ok {
return nil, os.NewError(fmt.Sprintf("Invalid public key blob; not a public key packet"))
}
return pk, nil
}