From: djm <djm@openbsd.org>
Date: Fri, 28 Oct 2022 00:44:44 +0000 (+0000)
Subject: refactor sshkey_private_deserialize
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a2c931d988e31395022f1322d85edf6de1b6b1db;p=openbsd

refactor sshkey_private_deserialize

feedback/ok markus@
---

diff --git a/usr.bin/ssh/ssh-dss.c b/usr.bin/ssh/ssh-dss.c
index 85641e47c9a..de804585861 100644
--- a/usr.bin/ssh/ssh-dss.c
+++ b/usr.bin/ssh/ssh-dss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-dss.c,v 1.47 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: ssh-dss.c,v 1.48 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -227,6 +227,27 @@ ssh_dss_deserialize_public(const char *ktype, struct sshbuf *b,
 	return ret;
 }
 
+static int
+ssh_dss_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+	BIGNUM *dsa_priv_key = NULL;
+
+	if (!sshkey_is_cert(key)) {
+		if ((r = ssh_dss_deserialize_public(ktype, b, key)) != 0)
+			return r;
+	}
+
+	if ((r = sshbuf_get_bignum2(b, &dsa_priv_key)) != 0)
+		return r;
+	if (!DSA_set0_key(key->dsa, NULL, dsa_priv_key)) {
+		BN_clear_free(dsa_priv_key);
+		return SSH_ERR_LIBCRYPTO_ERROR;
+	}
+	return 0;
+}
+
 static int
 ssh_dss_sign(struct sshkey *key,
     u_char **sigp, size_t *lenp,
@@ -395,6 +416,7 @@ static const struct sshkey_impl_funcs sshkey_dss_funcs = {
 	/* .ssh_serialize_public = */ ssh_dss_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_dss_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_dss_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_dss_deserialize_private,
 	/* .generate = */	ssh_dss_generate,
 	/* .copy_public = */	ssh_dss_copy_public,
 	/* .sign = */		ssh_dss_sign,
diff --git a/usr.bin/ssh/ssh-ecdsa-sk.c b/usr.bin/ssh/ssh-ecdsa-sk.c
index fc53dba54e2..04b02e08dc4 100644
--- a/usr.bin/ssh/ssh-ecdsa-sk.c
+++ b/usr.bin/ssh/ssh-ecdsa-sk.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-ecdsa-sk.c,v 1.16 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: ssh-ecdsa-sk.c,v 1.17 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -119,6 +119,23 @@ ssh_ecdsa_sk_deserialize_public(const char *ktype, struct sshbuf *b,
 	return 0;
 }
 
+static int
+ssh_ecdsa_sk_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+
+	if (!sshkey_is_cert(key)) {
+		if ((r = sshkey_ecdsa_funcs.deserialize_public(ktype,
+		    b, key)) != 0)
+			return r;
+	}
+	if ((r = sshkey_private_deserialize_sk(b, key)) != 0)
+		return r;
+
+	return 0;
+}
+
 /*
  * Check FIDO/W3C webauthn signatures clientData field against the expected
  * format and prepare a hash of it for use in signature verification.
@@ -387,6 +404,7 @@ static const struct sshkey_impl_funcs sshkey_ecdsa_sk_funcs = {
 	/* .ssh_serialize_public = */ ssh_ecdsa_sk_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_ecdsa_sk_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_ecdsa_sk_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_ecdsa_sk_deserialize_private,
 	/* .generate = */	NULL,
 	/* .copy_public = */	ssh_ecdsa_sk_copy_public,
 	/* .sign = */		NULL,
diff --git a/usr.bin/ssh/ssh-ecdsa.c b/usr.bin/ssh/ssh-ecdsa.c
index 8c08b232bc0..5677396feb1 100644
--- a/usr.bin/ssh/ssh-ecdsa.c
+++ b/usr.bin/ssh/ssh-ecdsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-ecdsa.c,v 1.24 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: ssh-ecdsa.c,v 1.25 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -149,50 +149,69 @@ static int
 ssh_ecdsa_deserialize_public(const char *ktype, struct sshbuf *b,
     struct sshkey *key)
 {
-	int ret = SSH_ERR_INTERNAL_ERROR;
+	int r;
 	char *curve = NULL;
-	EC_POINT *q = NULL;
 
-	key->ecdsa_nid = sshkey_ecdsa_nid_from_name(ktype);
-	if (sshbuf_get_cstring(b, &curve, NULL) != 0) {
-		ret = SSH_ERR_INVALID_FORMAT;
+	if ((key->ecdsa_nid = sshkey_ecdsa_nid_from_name(ktype)) == -1)
+		return SSH_ERR_INVALID_ARGUMENT;
+	if ((r = sshbuf_get_cstring(b, &curve, NULL)) != 0)
 		goto out;
-	}
 	if (key->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
-		ret = SSH_ERR_EC_CURVE_MISMATCH;
+		r = SSH_ERR_EC_CURVE_MISMATCH;
 		goto out;
 	}
 	EC_KEY_free(key->ecdsa);
+	key->ecdsa = NULL;
 	if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL) {
-		ret = SSH_ERR_EC_CURVE_INVALID;
+		r = SSH_ERR_LIBCRYPTO_ERROR;
 		goto out;
 	}
-	if ((q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL) {
-		ret = SSH_ERR_ALLOC_FAIL;
+	if ((r = sshbuf_get_eckey(b, key->ecdsa)) != 0)
 		goto out;
-	}
-	if (sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa)) != 0) {
-		ret = SSH_ERR_INVALID_FORMAT;
+	if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa),
+	    EC_KEY_get0_public_key(key->ecdsa)) != 0) {
+		r = SSH_ERR_KEY_INVALID_EC_VALUE;
 		goto out;
 	}
-	if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) {
-		ret = SSH_ERR_KEY_INVALID_EC_VALUE;
-		goto out;
+	/* success */
+	r = 0;
+#ifdef DEBUG_PK
+	sshkey_dump_ec_point(EC_KEY_get0_group(key->ecdsa),
+	    EC_KEY_get0_public_key(key->ecdsa));
+#endif
+ out:
+	free(curve);
+	if (r != 0) {
+		EC_KEY_free(key->ecdsa);
+		key->ecdsa = NULL;
 	}
-	if (EC_KEY_set_public_key(key->ecdsa, q) != 1) {
-		/* XXX assume it is a allocation error */
-		ret = SSH_ERR_ALLOC_FAIL;
+	return r;
+}
+
+static int
+ssh_ecdsa_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+	BIGNUM *exponent = NULL;
+
+	if (!sshkey_is_cert(key)) {
+		if ((r = ssh_ecdsa_deserialize_public(ktype, b, key)) != 0)
+			return r;
+	}
+	if ((r = sshbuf_get_bignum2(b, &exponent)) != 0)
+		goto out;
+	if (EC_KEY_set_private_key(key->ecdsa, exponent) != 1) {
+		r = SSH_ERR_LIBCRYPTO_ERROR;
 		goto out;
 	}
-#ifdef DEBUG_PK
-	sshkey_dump_ec_point(EC_KEY_get0_group(key->ecdsa), q);
-#endif
+	if ((r = sshkey_ec_validate_private(key->ecdsa)) != 0)
+		goto out;
 	/* success */
-	ret = 0;
+	r = 0;
  out:
-	free(curve);
-	EC_POINT_free(q);
-	return ret;
+	BN_clear_free(exponent);
+	return r;
 }
 
 /* ARGSUSED */
@@ -359,6 +378,7 @@ const struct sshkey_impl_funcs sshkey_ecdsa_funcs = {
 	/* .ssh_serialize_public = */ ssh_ecdsa_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_ecdsa_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_ecdsa_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_ecdsa_deserialize_private,
 	/* .generate = */	ssh_ecdsa_generate,
 	/* .copy_public = */	ssh_ecdsa_copy_public,
 	/* .sign = */		ssh_ecdsa_sign,
diff --git a/usr.bin/ssh/ssh-ed25519-sk.c b/usr.bin/ssh/ssh-ed25519-sk.c
index b849c11f877..e0eb8ddcc64 100644
--- a/usr.bin/ssh/ssh-ed25519-sk.c
+++ b/usr.bin/ssh/ssh-ed25519-sk.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-ed25519-sk.c,v 1.14 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: ssh-ed25519-sk.c,v 1.15 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2019 Markus Friedl.  All rights reserved.
  *
@@ -106,6 +106,19 @@ ssh_ed25519_sk_deserialize_public(const char *ktype, struct sshbuf *b,
 	return 0;
 }
 
+static int
+ssh_ed25519_sk_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+
+	if ((r = sshkey_ed25519_funcs.deserialize_public(ktype, b, key)) != 0)
+		return r;
+	if ((r = sshkey_private_deserialize_sk(b, key)) != 0)
+		return r;
+	return 0;
+}
+
 static int
 ssh_ed25519_sk_verify(const struct sshkey *key,
     const u_char *sig, size_t siglen,
@@ -241,6 +254,7 @@ static const struct sshkey_impl_funcs sshkey_ed25519_sk_funcs = {
 	/* .ssh_serialize_public = */ ssh_ed25519_sk_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_ed25519_sk_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_ed25519_sk_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_ed25519_sk_deserialize_private,
 	/* .generate = */	NULL,
 	/* .copy_public = */	ssh_ed25519_sk_copy_public,
 	/* .sign = */		NULL,
diff --git a/usr.bin/ssh/ssh-ed25519.c b/usr.bin/ssh/ssh-ed25519.c
index 7eba61710db..06c6a04dc1a 100644
--- a/usr.bin/ssh/ssh-ed25519.c
+++ b/usr.bin/ssh/ssh-ed25519.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-ed25519.c,v 1.18 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: ssh-ed25519.c,v 1.19 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2013 Markus Friedl <markus@openbsd.org>
  *
@@ -114,6 +114,31 @@ ssh_ed25519_deserialize_public(const char *ktype, struct sshbuf *b,
 	return 0;
 }
 
+static int
+ssh_ed25519_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+	size_t sklen = 0;
+	u_char *ed25519_sk = NULL;
+
+	if ((r = ssh_ed25519_deserialize_public(NULL, b, key)) != 0)
+		goto out;
+	if ((r = sshbuf_get_string(b, &ed25519_sk, &sklen)) != 0)
+		goto out;
+	if (sklen != ED25519_SK_SZ) {
+		r = SSH_ERR_INVALID_FORMAT;
+		goto out;
+	}
+	key->ed25519_sk = ed25519_sk;
+	ed25519_sk = NULL; /* transferred */
+	/* success */
+	r = 0;
+ out:
+	freezero(ed25519_sk, sklen);
+	return r;
+}
+
 static int
 ssh_ed25519_sign(struct sshkey *key,
     u_char **sigp, size_t *lenp,
@@ -253,6 +278,7 @@ const struct sshkey_impl_funcs sshkey_ed25519_funcs = {
 	/* .ssh_serialize_public = */ ssh_ed25519_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_ed25519_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_ed25519_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_ed25519_deserialize_private,
 	/* .generate = */	ssh_ed25519_generate,
 	/* .copy_public = */	ssh_ed25519_copy_public,
 	/* .sign = */		ssh_ed25519_sign,
diff --git a/usr.bin/ssh/ssh-rsa.c b/usr.bin/ssh/ssh-rsa.c
index cbb86001aef..31c9add11ac 100644
--- a/usr.bin/ssh/ssh-rsa.c
+++ b/usr.bin/ssh/ssh-rsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-rsa.c,v 1.76 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: ssh-rsa.c,v 1.77 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org>
  *
@@ -226,6 +226,60 @@ ssh_rsa_deserialize_public(const char *ktype, struct sshbuf *b,
 	return ret;
 }
 
+static int
+ssh_rsa_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+	BIGNUM *rsa_n = NULL, *rsa_e = NULL, *rsa_d = NULL;
+	BIGNUM *rsa_iqmp = NULL, *rsa_p = NULL, *rsa_q = NULL;
+
+	/* Note: can't reuse ssh_rsa_deserialize_public: e, n vs. n, e */
+	if (!sshkey_is_cert(key)) {
+		if ((r = sshbuf_get_bignum2(b, &rsa_n)) != 0 ||
+		    (r = sshbuf_get_bignum2(b, &rsa_e)) != 0)
+			goto out;
+		if (!RSA_set0_key(key->rsa, rsa_n, rsa_e, NULL)) {
+			r = SSH_ERR_LIBCRYPTO_ERROR;
+			goto out;
+		}
+		rsa_n = rsa_e = NULL; /* transferred */
+	}
+	if ((r = sshbuf_get_bignum2(b, &rsa_d)) != 0 ||
+	    (r = sshbuf_get_bignum2(b, &rsa_iqmp)) != 0 ||
+	    (r = sshbuf_get_bignum2(b, &rsa_p)) != 0 ||
+	    (r = sshbuf_get_bignum2(b, &rsa_q)) != 0)
+		goto out;
+	if (!RSA_set0_key(key->rsa, NULL, NULL, rsa_d)) {
+		r = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
+	rsa_d = NULL; /* transferred */
+	if (!RSA_set0_factors(key->rsa, rsa_p, rsa_q)) {
+		r = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
+	rsa_p = rsa_q = NULL; /* transferred */
+	if ((r = sshkey_check_rsa_length(key, 0)) != 0)
+		goto out;
+	if ((r = ssh_rsa_complete_crt_parameters(key, rsa_iqmp)) != 0)
+		goto out;
+	if (RSA_blinding_on(key->rsa, NULL) != 1) {
+		r = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
+	/* success */
+	r = 0;
+ out:
+	BN_clear_free(rsa_n);
+	BN_clear_free(rsa_e);
+	BN_clear_free(rsa_d);
+	BN_clear_free(rsa_p);
+	BN_clear_free(rsa_q);
+	BN_clear_free(rsa_iqmp);
+	return r;
+}
+
 static const char *
 rsa_hash_alg_ident(int hash_alg)
 {
@@ -645,6 +699,7 @@ static const struct sshkey_impl_funcs sshkey_rsa_funcs = {
 	/* .ssh_serialize_public = */ ssh_rsa_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_rsa_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_rsa_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_rsa_deserialize_private,
 	/* .generate = */	ssh_rsa_generate,
 	/* .copy_public = */	ssh_rsa_copy_public,
 	/* .sign = */		ssh_rsa_sign,
diff --git a/usr.bin/ssh/ssh-xmss.c b/usr.bin/ssh/ssh-xmss.c
index 2bd29882003..5601b338fd9 100644
--- a/usr.bin/ssh/ssh-xmss.c
+++ b/usr.bin/ssh/ssh-xmss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-xmss.c,v 1.13 2022/10/28 00:44:17 djm Exp $*/
+/* $OpenBSD: ssh-xmss.c,v 1.14 2022/10/28 00:44:44 djm Exp $*/
 /*
  * Copyright (c) 2017 Stefan-Lukas Gazdag.
  * Copyright (c) 2017 Markus Friedl.
@@ -155,6 +155,43 @@ ssh_xmss_deserialize_public(const char *ktype, struct sshbuf *b,
 	return ret;
 }
 
+static int
+ssh_xmss_deserialize_private(const char *ktype, struct sshbuf *b,
+    struct sshkey *key)
+{
+	int r;
+	char *xmss_name = NULL;
+	size_t pklen = 0, sklen = 0;
+	u_char *xmss_pk = NULL, *xmss_sk = NULL;
+
+	/* Note: can't reuse ssh_xmss_deserialize_public because of sk order */
+	if ((r = sshbuf_get_cstring(b, &xmss_name, NULL)) != 0 ||
+	    (r = sshbuf_get_string(b, &xmss_pk, &pklen)) != 0 ||
+	    (r = sshbuf_get_string(b, &xmss_sk, &sklen)) != 0)
+		goto out;
+	if (!sshkey_is_cert(key) &&
+	    (r = sshkey_xmss_init(key, xmss_name)) != 0)
+		goto out;
+	if (pklen != sshkey_xmss_pklen(key) ||
+	    sklen != sshkey_xmss_sklen(key)) {
+		r = SSH_ERR_INVALID_FORMAT;
+		goto out;
+	}
+	key->xmss_pk = xmss_pk;
+	key->xmss_sk = xmss_sk;
+	xmss_pk = xmss_sk = NULL;
+	/* optional internal state */
+	if ((r = sshkey_xmss_deserialize_state_opt(key, b)) != 0)
+		goto out;
+	/* success */
+	r = 0;
+ out:
+	free(xmss_name);
+	freezero(xmss_pk, pklen);
+	freezero(xmss_sk, sklen);
+	return r;
+}
+
 static int
 ssh_xmss_sign(struct sshkey *key,
     u_char **sigp, size_t *lenp,
@@ -314,6 +351,7 @@ static const struct sshkey_impl_funcs sshkey_xmss_funcs = {
 	/* .ssh_serialize_public = */ ssh_xmss_serialize_public,
 	/* .ssh_deserialize_public = */ ssh_xmss_deserialize_public,
 	/* .ssh_serialize_private = */ ssh_xmss_serialize_private,
+	/* .ssh_deserialize_private = */ ssh_xmss_deserialize_private,
 	/* .generate = */	sshkey_xmss_generate_private_key,
 	/* .copy_public = */	ssh_xmss_copy_public,
 	/* .sign = */		ssh_xmss_sign,
diff --git a/usr.bin/ssh/sshkey.c b/usr.bin/ssh/sshkey.c
index 0644d593a41..c61b4e2fb55 100644
--- a/usr.bin/ssh/sshkey.c
+++ b/usr.bin/ssh/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.132 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: sshkey.c,v 1.133 2022/10/28 00:44:44 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -2430,24 +2430,33 @@ sshkey_private_serialize(struct sshkey *key, struct sshbuf *b)
 	    SSHKEY_SERIALIZE_DEFAULT);
 }
 
+/* Shared deserialization of FIDO private key components */
+int
+sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k)
+{
+	int r;
+
+	if ((k->sk_key_handle = sshbuf_new()) == NULL ||
+	    (k->sk_reserved = sshbuf_new()) == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+	if ((r = sshbuf_get_cstring(buf, &k->sk_application, NULL)) != 0 ||
+	    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
+	    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
+	    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
+		return r;
+
+	return 0;
+}
+
 int
 sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
 {
-	char *tname = NULL, *curve = NULL, *xmss_name = NULL;
+	const struct sshkey_impl *impl;
+	char *tname = NULL;
 	char *expect_sk_application = NULL;
+	u_char *expect_ed25519_pk = NULL;
 	struct sshkey *k = NULL;
-	size_t pklen = 0, sklen = 0;
 	int type, r = SSH_ERR_INTERNAL_ERROR;
-	u_char *ed25519_pk = NULL, *ed25519_sk = NULL;
-	u_char *expect_ed25519_pk = NULL;
-	u_char *xmss_pk = NULL, *xmss_sk = NULL;
-#ifdef WITH_OPENSSL
-	BIGNUM *exponent = NULL;
-	BIGNUM *rsa_n = NULL, *rsa_e = NULL, *rsa_d = NULL;
-	BIGNUM *rsa_iqmp = NULL, *rsa_p = NULL, *rsa_q = NULL;
-	BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL;
-	BIGNUM *dsa_pub_key = NULL, *dsa_priv_key = NULL;
-#endif /* WITH_OPENSSL */
 
 	if (kp != NULL)
 		*kp = NULL;
@@ -2480,225 +2489,21 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
 		expect_ed25519_pk = k->ed25519_pk;
 		k->sk_application = NULL;
 		k->ed25519_pk = NULL;
+		/* XXX xmss too or refactor */
 	} else {
 		if ((k = sshkey_new(type)) == NULL) {
 			r = SSH_ERR_ALLOC_FAIL;
 			goto out;
 		}
 	}
-	switch (type) {
-#ifdef WITH_OPENSSL
-	case KEY_DSA:
-		if ((r = sshbuf_get_bignum2(buf, &dsa_p)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &dsa_q)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &dsa_g)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &dsa_pub_key)) != 0)
-			goto out;
-		if (!DSA_set0_pqg(k->dsa, dsa_p, dsa_q, dsa_g)) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		dsa_p = dsa_q = dsa_g = NULL; /* transferred */
-		if (!DSA_set0_key(k->dsa, dsa_pub_key, NULL)) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		dsa_pub_key = NULL; /* transferred */
-		/* FALLTHROUGH */
-	case KEY_DSA_CERT:
-		if ((r = sshbuf_get_bignum2(buf, &dsa_priv_key)) != 0)
-			goto out;
-		if (!DSA_set0_key(k->dsa, NULL, dsa_priv_key)) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		dsa_priv_key = NULL; /* transferred */
-		break;
-	case KEY_ECDSA:
-		if ((k->ecdsa_nid = sshkey_ecdsa_nid_from_name(tname)) == -1) {
-			r = SSH_ERR_INVALID_ARGUMENT;
-			goto out;
-		}
-		if ((r = sshbuf_get_cstring(buf, &curve, NULL)) != 0)
-			goto out;
-		if (k->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
-			r = SSH_ERR_EC_CURVE_MISMATCH;
-			goto out;
-		}
-		k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
-		if (k->ecdsa  == NULL) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		if ((r = sshbuf_get_eckey(buf, k->ecdsa)) != 0)
-			goto out;
-		/* FALLTHROUGH */
-	case KEY_ECDSA_CERT:
-		if ((r = sshbuf_get_bignum2(buf, &exponent)) != 0)
-			goto out;
-		if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
-		    EC_KEY_get0_public_key(k->ecdsa))) != 0 ||
-		    (r = sshkey_ec_validate_private(k->ecdsa)) != 0)
-			goto out;
-		break;
-	case KEY_ECDSA_SK:
-		if ((k->ecdsa_nid = sshkey_ecdsa_nid_from_name(tname)) == -1) {
-			r = SSH_ERR_INVALID_ARGUMENT;
-			goto out;
-		}
-		if ((r = sshbuf_get_cstring(buf, &curve, NULL)) != 0)
-			goto out;
-		if (k->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
-			r = SSH_ERR_EC_CURVE_MISMATCH;
-			goto out;
-		}
-		if ((k->sk_key_handle = sshbuf_new()) == NULL ||
-		    (k->sk_reserved = sshbuf_new()) == NULL) {
-			r = SSH_ERR_ALLOC_FAIL;
-			goto out;
-		}
-		k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
-		if (k->ecdsa  == NULL) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		if ((r = sshbuf_get_eckey(buf, k->ecdsa)) != 0 ||
-		    (r = sshbuf_get_cstring(buf, &k->sk_application,
-		    NULL)) != 0 ||
-		    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
-		    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
-		    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
-			goto out;
-		if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
-		    EC_KEY_get0_public_key(k->ecdsa))) != 0)
-			goto out;
-		break;
-	case KEY_ECDSA_SK_CERT:
-		if ((k->sk_key_handle = sshbuf_new()) == NULL ||
-		    (k->sk_reserved = sshbuf_new()) == NULL) {
-			r = SSH_ERR_ALLOC_FAIL;
-			goto out;
-		}
-		if ((r = sshbuf_get_cstring(buf, &k->sk_application,
-		    NULL)) != 0 ||
-		    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
-		    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
-		    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
-			goto out;
-		if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
-		    EC_KEY_get0_public_key(k->ecdsa))) != 0)
-			goto out;
-		break;
-	case KEY_RSA:
-		if ((r = sshbuf_get_bignum2(buf, &rsa_n)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &rsa_e)) != 0)
-			goto out;
-		if (!RSA_set0_key(k->rsa, rsa_n, rsa_e, NULL)) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		rsa_n = rsa_e = NULL; /* transferred */
-		/* FALLTHROUGH */
-	case KEY_RSA_CERT:
-		if ((r = sshbuf_get_bignum2(buf, &rsa_d)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &rsa_iqmp)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &rsa_p)) != 0 ||
-		    (r = sshbuf_get_bignum2(buf, &rsa_q)) != 0)
-			goto out;
-		if (!RSA_set0_key(k->rsa, NULL, NULL, rsa_d)) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		rsa_d = NULL; /* transferred */
-		if (!RSA_set0_factors(k->rsa, rsa_p, rsa_q)) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		rsa_p = rsa_q = NULL; /* transferred */
-		if ((r = sshkey_check_rsa_length(k, 0)) != 0)
-			goto out;
-		if ((r = ssh_rsa_complete_crt_parameters(k, rsa_iqmp)) != 0)
-			goto out;
-		break;
-#endif /* WITH_OPENSSL */
-	case KEY_ED25519:
-	case KEY_ED25519_CERT:
-		if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0 ||
-		    (r = sshbuf_get_string(buf, &ed25519_sk, &sklen)) != 0)
-			goto out;
-		if (pklen != ED25519_PK_SZ || sklen != ED25519_SK_SZ) {
-			r = SSH_ERR_INVALID_FORMAT;
-			goto out;
-		}
-		k->ed25519_pk = ed25519_pk;
-		k->ed25519_sk = ed25519_sk;
-		ed25519_pk = ed25519_sk = NULL; /* transferred */
-		break;
-	case KEY_ED25519_SK:
-	case KEY_ED25519_SK_CERT:
-		if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0)
-			goto out;
-		if (pklen != ED25519_PK_SZ) {
-			r = SSH_ERR_INVALID_FORMAT;
-			goto out;
-		}
-		if ((k->sk_key_handle = sshbuf_new()) == NULL ||
-		    (k->sk_reserved = sshbuf_new()) == NULL) {
-			r = SSH_ERR_ALLOC_FAIL;
-			goto out;
-		}
-		if ((r = sshbuf_get_cstring(buf, &k->sk_application,
-		    NULL)) != 0 ||
-		    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
-		    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
-		    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
-			goto out;
-		k->ed25519_pk = ed25519_pk;
-		ed25519_pk = NULL; /* transferred */
-		break;
-#ifdef WITH_XMSS
-	case KEY_XMSS:
-	case KEY_XMSS_CERT:
-		if ((r = sshbuf_get_cstring(buf, &xmss_name, NULL)) != 0 ||
-		    (r = sshbuf_get_string(buf, &xmss_pk, &pklen)) != 0 ||
-		    (r = sshbuf_get_string(buf, &xmss_sk, &sklen)) != 0)
-			goto out;
-		if (type == KEY_XMSS &&
-		    (r = sshkey_xmss_init(k, xmss_name)) != 0)
-			goto out;
-		if (pklen != sshkey_xmss_pklen(k) ||
-		    sklen != sshkey_xmss_sklen(k)) {
-			r = SSH_ERR_INVALID_FORMAT;
-			goto out;
-		}
-		k->xmss_pk = xmss_pk;
-		k->xmss_sk = xmss_sk;
-		xmss_pk = xmss_sk = NULL;
-		/* optional internal state */
-		if ((r = sshkey_xmss_deserialize_state_opt(k, buf)) != 0)
-			goto out;
-		break;
-#endif /* WITH_XMSS */
-	default:
-		r = SSH_ERR_KEY_TYPE_UNKNOWN;
+	if ((impl = sshkey_impl_from_type(type)) == NULL) {
+		r = SSH_ERR_INTERNAL_ERROR;
 		goto out;
 	}
-#ifdef WITH_OPENSSL
-	/* enable blinding */
-	switch (k->type) {
-	case KEY_RSA:
-	case KEY_RSA_CERT:
-		if (RSA_blinding_on(k->rsa, NULL) != 1) {
-			r = SSH_ERR_LIBCRYPTO_ERROR;
-			goto out;
-		}
-		break;
-	}
-#endif /* WITH_OPENSSL */
+	if ((r = impl->funcs->deserialize_private(tname, buf, k)) != 0)
+		goto out;
+
+	/* XXX xmss too or refactor */
 	if ((expect_sk_application != NULL && (k->sk_application == NULL ||
 	    strcmp(expect_sk_application, k->sk_application) != 0)) ||
 	    (expect_ed25519_pk != NULL && (k->ed25519_pk == NULL ||
@@ -2714,27 +2519,7 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
 	}
  out:
 	free(tname);
-	free(curve);
-#ifdef WITH_OPENSSL
-	BN_clear_free(exponent);
-	BN_clear_free(dsa_p);
-	BN_clear_free(dsa_q);
-	BN_clear_free(dsa_g);
-	BN_clear_free(dsa_pub_key);
-	BN_clear_free(dsa_priv_key);
-	BN_clear_free(rsa_n);
-	BN_clear_free(rsa_e);
-	BN_clear_free(rsa_d);
-	BN_clear_free(rsa_p);
-	BN_clear_free(rsa_q);
-	BN_clear_free(rsa_iqmp);
-#endif /* WITH_OPENSSL */
 	sshkey_free(k);
-	freezero(ed25519_pk, pklen);
-	freezero(ed25519_sk, sklen);
-	free(xmss_name);
-	freezero(xmss_pk, pklen);
-	freezero(xmss_sk, sklen);
 	free(expect_sk_application);
 	free(expect_ed25519_pk);
 	return r;
diff --git a/usr.bin/ssh/sshkey.h b/usr.bin/ssh/sshkey.h
index ea3771393f7..e90a1eec8cb 100644
--- a/usr.bin/ssh/sshkey.h
+++ b/usr.bin/ssh/sshkey.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.h,v 1.60 2022/10/28 00:44:17 djm Exp $ */
+/* $OpenBSD: sshkey.h,v 1.61 2022/10/28 00:44:44 djm Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -169,6 +169,8 @@ struct sshkey_impl_funcs {
 	    struct sshkey *);
 	int (*serialize_private)(const struct sshkey *, struct sshbuf *,
 	    enum sshkey_serialize_rep);
+	int (*deserialize_private)(const char *, struct sshbuf *,
+	    struct sshkey *);
 	int (*generate)(struct sshkey *, int);	/* optional */
 	int (*copy_public)(const struct sshkey *, struct sshkey *);
 	int (*sign)(struct sshkey *, u_char **, size_t *,
@@ -322,6 +324,7 @@ int	sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to);
 int	sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key);
 int	sshkey_serialize_private_sk(const struct sshkey *key,
     struct sshbuf *buf);
+int	sshkey_private_deserialize_sk(struct sshbuf *buf, struct sshkey *k);
 #ifdef WITH_OPENSSL
 int	check_rsa_length(const RSA *rsa); /* XXX remove */
 #endif