nebula/pkclient/pkclient.go

88 lines
1.7 KiB
Go

package pkclient
import (
"crypto/ecdsa"
"crypto/x509"
"fmt"
"io"
"strconv"
"github.com/stefanberger/go-pkcs11uri"
)
type Client interface {
io.Closer
GetPubKey() ([]byte, error)
DeriveNoise(peerPubKey []byte) ([]byte, error)
Test() error
}
const NoiseKeySize = 32
func FromUrl(pkurl string) (*PKClient, error) {
uri := pkcs11uri.New()
uri.SetAllowAnyModule(true) //todo
err := uri.Parse(pkurl)
if err != nil {
return nil, err
}
module, err := uri.GetModule()
if err != nil {
return nil, err
}
slotid := 0
slot, ok := uri.GetPathAttribute("slot-id", false)
if !ok {
slotid = 0
} else {
slotid, err = strconv.Atoi(slot)
if err != nil {
return nil, err
}
}
pin, _ := uri.GetPIN()
id, _ := uri.GetPathAttribute("id", false)
label, _ := uri.GetPathAttribute("object", false)
return New(module, uint(slotid), pin, id, label)
}
func ecKeyToArray(key *ecdsa.PublicKey) []byte {
x := make([]byte, 32)
y := make([]byte, 32)
key.X.FillBytes(x)
key.Y.FillBytes(y)
return append([]byte{0x04}, append(x, y...)...)
}
func formatPubkeyFromPublicKeyInfoAttr(d []byte) ([]byte, error) {
e, err := x509.ParsePKIXPublicKey(d)
if err != nil {
return nil, err
}
switch t := e.(type) {
case *ecdsa.PublicKey:
return ecKeyToArray(e.(*ecdsa.PublicKey)), nil
default:
return nil, fmt.Errorf("unknown public key type: %T", t)
}
}
func (c *PKClient) Test() error {
pub, err := c.GetPubKey()
if err != nil {
return fmt.Errorf("failed to get public key: %w", err)
}
out, err := c.DeriveNoise(pub) //do an ECDH with ourselves as a quick test
if err != nil {
return err
}
if len(out) != NoiseKeySize {
return fmt.Errorf("got a key of %d bytes, expected %d", len(out), NoiseKeySize)
}
return nil
}