ssh: support ECDSA private keys in OpenSSH format
This adds support for parsing OpenSSH ECDSA private keys. It
implements parsing for P-256, P-384, and P-521 keys.
Fixes golang/go#36722
Change-Id: I77c8e0a23ed6353f6667686cc79ec14661cb10db
GitHub-Last-Rev: 2324b920d080fc7ac35fbcf0a79e25161b6a7f82
GitHub-Pull-Request: golang/crypto#114
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/215540
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/ssh/keys.go b/ssh/keys.go
index 5377ec8..d63cbf6 100644
--- a/ssh/keys.go
+++ b/ssh/keys.go
@@ -1366,6 +1366,57 @@
pk := ed25519.PrivateKey(make([]byte, ed25519.PrivateKeySize))
copy(pk, key.Priv)
return &pk, nil
+ case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521:
+ key := struct {
+ Curve string
+ Pub []byte
+ D *big.Int
+ Comment string
+ Pad []byte `ssh:"rest"`
+ }{}
+
+ if err := Unmarshal(pk1.Rest, &key); err != nil {
+ return nil, err
+ }
+
+ if err := checkOpenSSHKeyPadding(key.Pad); err != nil {
+ return nil, err
+ }
+
+ var curve elliptic.Curve
+ switch key.Curve {
+ case "nistp256":
+ curve = elliptic.P256()
+ case "nistp384":
+ curve = elliptic.P384()
+ case "nistp521":
+ curve = elliptic.P521()
+ default:
+ return nil, errors.New("ssh: unhandled elliptic curve: " + key.Curve)
+ }
+
+ X, Y := elliptic.Unmarshal(curve, key.Pub)
+ if X == nil || Y == nil {
+ return nil, errors.New("ssh: failed to unmarshal public key")
+ }
+
+ if key.D.Cmp(curve.Params().N) >= 0 {
+ return nil, errors.New("ssh: scalar is out of range")
+ }
+
+ x, y := curve.ScalarBaseMult(key.D.Bytes())
+ if x.Cmp(X) != 0 || y.Cmp(Y) != 0 {
+ return nil, errors.New("ssh: public key does not match private key")
+ }
+
+ return &ecdsa.PrivateKey{
+ PublicKey: ecdsa.PublicKey{
+ Curve: curve,
+ X: X,
+ Y: Y,
+ },
+ D: key.D,
+ }, nil
default:
return nil, errors.New("ssh: unhandled key type")
}
diff --git a/ssh/testdata/keys.go b/ssh/testdata/keys.go
index 72cfaa0..a7da078 100644
--- a/ssh/testdata/keys.go
+++ b/ssh/testdata/keys.go
@@ -114,6 +114,37 @@
ANkaHTTaPojClO0dKJ/Zjs7pWOCGliebBYprQ/Y4r9QLBkC/XaWMS26gFIrjgC7D2Rv+rZ
wSD0v0RcmkITP1ZR0AAAAYcHF1ZXJuYUBMdWNreUh5ZHJvLmxvY2FsAQID
-----END OPENSSH PRIVATE KEY-----`),
+ "p256-openssh-format": []byte(`-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAaAAAABNlY2RzYS
+1zaGEyLW5pc3RwMjU2AAAACG5pc3RwMjU2AAAAQQSN5Ld/DFy8LJK0yrWg+Ryhq4/ifHry
+QyCQeT4UXSB+UGdRct7kWA0hARbTaSCh+8U/Gs5O+IkDNoTKVsgxKUMQAAAAsO3C7nPtwu
+5zAAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBI3kt38MXLwskrTK
+taD5HKGrj+J8evJDIJB5PhRdIH5QZ1Fy3uRYDSEBFtNpIKH7xT8azk74iQM2hMpWyDEpQx
+AAAAAhAIHB48R+goZaiXndfYTrwk4BT1+MeLPC2/dwe0J5d1QDAAAAE21hcmlhbm9AZW5k
+b3IubG9jYWwBAgME
+-----END OPENSSH PRIVATE KEY-----`),
+ "p384-openssh-format": []byte(`-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAiAAAABNlY2RzYS
+1zaGEyLW5pc3RwMzg0AAAACG5pc3RwMzg0AAAAYQTZb2VzEPs2NN/i1qHddKTVfwoIq3Tf
+PeQ/kcWBvuCVJfIygvpm9MeusawEPuLSEXwiNDew+YHZ9xHIvFjCmZsLuEOzuh9t9KotwM
+57H+7N+RDFzhM2j8hAaOuT5XDLKfUAAADgn/Sny5/0p8sAAAATZWNkc2Etc2hhMi1uaXN0
+cDM4NAAAAAhuaXN0cDM4NAAAAGEE2W9lcxD7NjTf4tah3XSk1X8KCKt03z3kP5HFgb7glS
+XyMoL6ZvTHrrGsBD7i0hF8IjQ3sPmB2fcRyLxYwpmbC7hDs7ofbfSqLcDOex/uzfkQxc4T
+No/IQGjrk+Vwyyn1AAAAMQDg0hwGKB/9Eq+e2FeTspi8QHW5xTD6prqsHDFx4cKk0ccgFV
+61dhFhD/8SEbYlHzEAAAATbWFyaWFub0BlbmRvci5sb2NhbAECAwQ=
+-----END OPENSSH PRIVATE KEY-----`),
+ "p521-openssh-format": []byte(`-----BEGIN OPENSSH PRIVATE KEY-----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+-----END OPENSSH PRIVATE KEY-----`),
"user": []byte(`-----BEGIN EC PRIVATE KEY-----
MHcCAQEEILYCAeq8f7V4vSSypRw7pxy8yz3V5W4qg8kSC3zJhqpQoAoGCCqGSM49
AwEHoUQDQgAEYcO2xNKiRUYOLEHM7VYAp57HNyKbOdYtHD83Z4hzNPVC4tM5mdGD
