refactor sshkey_from_private()

feedback/ok markus@

diff --git a/usr.bin/ssh/ssh-dss.c b/usr.bin/ssh/ssh-dss.c
index 6b2c487..2dba1ed 100644 (file)
--- a/usr.bin/ssh/ssh-dss.c
+++ b/usr.bin/ssh/ssh-dss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-dss.c,v 1.43 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: ssh-dss.c,v 1.44 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -136,6 +136,43 @@ ssh_dss_generate(struct sshkey *k, int bits)
        return 0;
 }
 
+static int
+ssh_dss_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
+       BIGNUM *dsa_p_dup = NULL, *dsa_q_dup = NULL, *dsa_g_dup = NULL;
+       BIGNUM *dsa_pub_key_dup = NULL;
+       int r = SSH_ERR_INTERNAL_ERROR;
+
+       DSA_get0_pqg(from->dsa, &dsa_p, &dsa_q, &dsa_g);
+       DSA_get0_key(from->dsa, &dsa_pub_key, NULL);
+       if ((dsa_p_dup = BN_dup(dsa_p)) == NULL ||
+           (dsa_q_dup = BN_dup(dsa_q)) == NULL ||
+           (dsa_g_dup = BN_dup(dsa_g)) == NULL ||
+           (dsa_pub_key_dup = BN_dup(dsa_pub_key)) == NULL) {
+               r = SSH_ERR_ALLOC_FAIL;
+               goto out;
+       }
+       if (!DSA_set0_pqg(to->dsa, dsa_p_dup, dsa_q_dup, dsa_g_dup)) {
+               r = SSH_ERR_LIBCRYPTO_ERROR;
+               goto out;
+       }
+       dsa_p_dup = dsa_q_dup = dsa_g_dup = NULL; /* transferred */
+       if (!DSA_set0_key(to->dsa, dsa_pub_key_dup, NULL)) {
+               r = SSH_ERR_LIBCRYPTO_ERROR;
+               goto out;
+       }
+       dsa_pub_key_dup = NULL; /* transferred */
+       /* success */
+       r = 0;
+ out:
+       BN_clear_free(dsa_p_dup);
+       BN_clear_free(dsa_q_dup);
+       BN_clear_free(dsa_g_dup);
+       BN_clear_free(dsa_pub_key_dup);
+       return r;
+}
+
 int
 ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
     const u_char *data, size_t datalen, u_int compat)
@@ -300,6 +337,7 @@ static const struct sshkey_impl_funcs sshkey_dss_funcs = {
        /* .equal = */          ssh_dss_equal,
        /* .ssh_serialize_public = */ ssh_dss_serialize_public,
        /* .generate = */       ssh_dss_generate,
+       /* .copy_public = */    ssh_dss_copy_public,
 };
 
 const struct sshkey_impl sshkey_dss_impl = {

diff --git a/usr.bin/ssh/ssh-ecdsa-sk.c b/usr.bin/ssh/ssh-ecdsa-sk.c
index 5c844d8..f3692b0 100644 (file)
--- 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 1.12 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: ssh-ecdsa-sk.c,v 1.13 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -78,6 +78,18 @@ ssh_ecdsa_sk_serialize_public(const struct sshkey *key, struct sshbuf *b,
        return 0;
 }
 
+static int
+ssh_ecdsa_sk_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       int r;
+
+       if ((r = sshkey_ecdsa_funcs.copy_public(from, to)) != 0)
+               return r;
+       if ((r = sshkey_copy_public_sk(from, to)) != 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.
@@ -345,6 +357,7 @@ static const struct sshkey_impl_funcs sshkey_ecdsa_sk_funcs = {
        /* .equal = */          ssh_ecdsa_sk_equal,
        /* .ssh_serialize_public = */ ssh_ecdsa_sk_serialize_public,
        /* .generate = */       NULL,
+       /* .copy_public = */    ssh_ecdsa_sk_copy_public,
 };
 
 const struct sshkey_impl sshkey_ecdsa_sk_impl = {

diff --git a/usr.bin/ssh/ssh-ecdsa.c b/usr.bin/ssh/ssh-ecdsa.c
index 9e57664..b2b0320 100644 (file)
--- a/usr.bin/ssh/ssh-ecdsa.c
+++ b/usr.bin/ssh/ssh-ecdsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-ecdsa.c,v 1.20 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: ssh-ecdsa.c,v 1.21 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -118,6 +118,18 @@ ssh_ecdsa_generate(struct sshkey *k, int bits)
        return 0;
 }
 
+static int
+ssh_ecdsa_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       to->ecdsa_nid = from->ecdsa_nid;
+       if ((to->ecdsa = EC_KEY_new_by_curve_name(from->ecdsa_nid)) == NULL)
+               return SSH_ERR_ALLOC_FAIL;
+       if (EC_KEY_set_public_key(to->ecdsa,
+           EC_KEY_get0_public_key(from->ecdsa)) != 1)
+               return SSH_ERR_LIBCRYPTO_ERROR; /* caller will free k->ecdsa */
+       return 0;
+}
+
 /* ARGSUSED */
 int
 ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
@@ -278,6 +290,7 @@ const struct sshkey_impl_funcs sshkey_ecdsa_funcs = {
        /* .equal = */          ssh_ecdsa_equal,
        /* .ssh_serialize_public = */ ssh_ecdsa_serialize_public,
        /* .generate = */       ssh_ecdsa_generate,
+       /* .copy_public = */    ssh_ecdsa_copy_public,
 };
 
 const struct sshkey_impl sshkey_ecdsa_nistp256_impl = {

diff --git a/usr.bin/ssh/ssh-ed25519-sk.c b/usr.bin/ssh/ssh-ed25519-sk.c
index 7131363..99676d9 100644 (file)
--- 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 1.10 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: ssh-ed25519-sk.c,v 1.11 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2019 Markus Friedl.  All rights reserved.
  *
@@ -68,6 +68,18 @@ ssh_ed25519_sk_serialize_public(const struct sshkey *key, struct sshbuf *b,
        return 0;
 }
 
+static int
+ssh_ed25519_sk_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       int r;
+
+       if ((r = sshkey_ed25519_funcs.copy_public(from, to)) != 0)
+               return r;
+       if ((r = sshkey_copy_public_sk(from, to)) != 0)
+               return r;
+       return 0;
+}
+
 int
 ssh_ed25519_sk_verify(const struct sshkey *key,
     const u_char *signature, size_t signaturelen,
@@ -202,6 +214,7 @@ static const struct sshkey_impl_funcs sshkey_ed25519_sk_funcs = {
        /* .equal = */          ssh_ed25519_sk_equal,
        /* .ssh_serialize_public = */ ssh_ed25519_sk_serialize_public,
        /* .generate = */       NULL,
+       /* .copy_public = */    ssh_ed25519_sk_copy_public,
 };
 
 const struct sshkey_impl sshkey_ed25519_sk_impl = {

diff --git a/usr.bin/ssh/ssh-ed25519.c b/usr.bin/ssh/ssh-ed25519.c
index bbf164c..db1dc96 100644 (file)
--- a/usr.bin/ssh/ssh-ed25519.c
+++ b/usr.bin/ssh/ssh-ed25519.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-ed25519.c,v 1.14 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: ssh-ed25519.c,v 1.15 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2013 Markus Friedl <markus@openbsd.org>
  *
@@ -73,6 +73,17 @@ ssh_ed25519_generate(struct sshkey *k, int bits)
        return 0;
 }
 
+static int
+ssh_ed25519_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       if (from->ed25519_pk == NULL)
+               return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */
+       if ((to->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL)
+               return SSH_ERR_ALLOC_FAIL;
+       memcpy(to->ed25519_pk, from->ed25519_pk, ED25519_PK_SZ);
+       return 0;
+}
+
 int
 ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
     const u_char *data, size_t datalen, u_int compat)
@@ -208,6 +219,7 @@ const struct sshkey_impl_funcs sshkey_ed25519_funcs = {
        /* .equal = */          ssh_ed25519_equal,
        /* .ssh_serialize_public = */ ssh_ed25519_serialize_public,
        /* .generate = */       ssh_ed25519_generate,
+       /* .copy_public = */    ssh_ed25519_copy_public,
 };
 
 const struct sshkey_impl sshkey_ed25519_impl = {

diff --git a/usr.bin/ssh/ssh-rsa.c b/usr.bin/ssh/ssh-rsa.c
index f6aa4bf..f13a082 100644 (file)
--- a/usr.bin/ssh/ssh-rsa.c
+++ b/usr.bin/ssh/ssh-rsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-rsa.c,v 1.72 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: ssh-rsa.c,v 1.73 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org>
  *
@@ -125,6 +125,32 @@ ssh_rsa_generate(struct sshkey *k, int bits)
        return ret;
 }
 
+static int
+ssh_rsa_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       const BIGNUM *rsa_n, *rsa_e;
+       BIGNUM *rsa_n_dup = NULL, *rsa_e_dup = NULL;
+       int r = SSH_ERR_INTERNAL_ERROR;
+
+       RSA_get0_key(from->rsa, &rsa_n, &rsa_e, NULL);
+       if ((rsa_n_dup = BN_dup(rsa_n)) == NULL ||
+           (rsa_e_dup = BN_dup(rsa_e)) == NULL) {
+               r = SSH_ERR_ALLOC_FAIL;
+               goto out;
+       }
+       if (!RSA_set0_key(to->rsa, rsa_n_dup, rsa_e_dup, NULL)) {
+               r = SSH_ERR_LIBCRYPTO_ERROR;
+               goto out;
+       }
+       rsa_n_dup = rsa_e_dup = NULL; /* transferred */
+       /* success */
+       r = 0;
+ out:
+       BN_clear_free(rsa_n_dup);
+       BN_clear_free(rsa_e_dup);
+       return r;
+}
+
 static const char *
 rsa_hash_alg_ident(int hash_alg)
 {
@@ -540,6 +566,7 @@ static const struct sshkey_impl_funcs sshkey_rsa_funcs = {
        /* .equal = */          ssh_rsa_equal,
        /* .ssh_serialize_public = */ ssh_rsa_serialize_public,
        /* .generate = */       ssh_rsa_generate,
+       /* .copy_public = */    ssh_rsa_copy_public,
 };
 
 const struct sshkey_impl sshkey_rsa_impl = {

diff --git a/usr.bin/ssh/ssh-xmss.c b/usr.bin/ssh/ssh-xmss.c
index 30cd89c..7a3bec7 100644 (file)
--- a/usr.bin/ssh/ssh-xmss.c
+++ b/usr.bin/ssh/ssh-xmss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-xmss.c,v 1.9 2022/10/28 00:39:29 djm Exp $*/
+/* $OpenBSD: ssh-xmss.c,v 1.10 2022/10/28 00:41:17 djm Exp $*/
 /*
  * Copyright (c) 2017 Stefan-Lukas Gazdag.
  * Copyright (c) 2017 Markus Friedl.
@@ -79,6 +79,31 @@ ssh_xmss_serialize_public(const struct sshkey *key, struct sshbuf *b,
        return 0;
 }
 
+static int
+ssh_xmss_copy_public(const struct sshkey *from, struct sshkey *to)
+{
+       int r = SSH_ERR_INTERNAL_ERROR;
+       u_int32_t left;
+       size_t pklen;
+
+       if ((r = sshkey_xmss_init(to, from->xmss_name)) != 0)
+               return r;
+       if (from->xmss_pk == NULL)
+               return 0; /* XXX SSH_ERR_INTERNAL_ERROR ? */
+
+       if ((pklen = sshkey_xmss_pklen(from)) == 0 ||
+           sshkey_xmss_pklen(to) != pklen)
+               return SSH_ERR_INTERNAL_ERROR;
+       if ((to->xmss_pk = malloc(pklen)) == NULL)
+               return SSH_ERR_ALLOC_FAIL;
+       memcpy(to->xmss_pk, from->xmss_pk, pklen);
+       /* simulate number of signatures left on pubkey */
+       left = sshkey_xmss_signatures_left(from);
+       if (left)
+               sshkey_xmss_enable_maxsign(to, left);
+       return 0;
+}
+
 int
 ssh_xmss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
     const u_char *data, size_t datalen, u_int compat)
@@ -234,6 +259,7 @@ static const struct sshkey_impl_funcs sshkey_xmss_funcs = {
        /* .equal = */          ssh_xmss_equal,
        /* .ssh_serialize_public = */ ssh_xmss_serialize_public,
        /* .generate = */       sshkey_xmss_generate_private_key,
+       /* .copy_public = */    ssh_xmss_copy_public,
 };
 
 const struct sshkey_impl sshkey_xmss_impl = {

diff --git a/usr.bin/ssh/sshkey.c b/usr.bin/ssh/sshkey.c
index 74ee6b4..7a6daeb 100644 (file)
--- a/usr.bin/ssh/sshkey.c
+++ b/usr.bin/ssh/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.127 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: sshkey.c,v 1.128 2022/10/28 00:41:17 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -1405,131 +1405,31 @@ sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key)
        return r;
 }
 
+int
+sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to)
+{
+       /* Append security-key application string */
+       if ((to->sk_application = strdup(from->sk_application)) == NULL)
+               return SSH_ERR_ALLOC_FAIL;
+       return 0;
+}
+
 int
 sshkey_from_private(const struct sshkey *k, struct sshkey **pkp)
 {
        struct sshkey *n = NULL;
        int r = SSH_ERR_INTERNAL_ERROR;
-#ifdef WITH_OPENSSL
-       const BIGNUM *rsa_n, *rsa_e;
-       BIGNUM *rsa_n_dup = NULL, *rsa_e_dup = NULL;
-       const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
-       BIGNUM *dsa_p_dup = NULL, *dsa_q_dup = NULL, *dsa_g_dup = NULL;
-       BIGNUM *dsa_pub_key_dup = NULL;
-#endif /* WITH_OPENSSL */
+       const struct sshkey_impl *impl;
 
        *pkp = NULL;
+       if ((impl = sshkey_impl_from_key(k)) == NULL)
+               return SSH_ERR_KEY_TYPE_UNKNOWN;
        if ((n = sshkey_new(k->type)) == NULL) {
                r = SSH_ERR_ALLOC_FAIL;
                goto out;
        }
-       switch (k->type) {
-#ifdef WITH_OPENSSL
-       case KEY_DSA:
-       case KEY_DSA_CERT:
-               DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
-               DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
-               if ((dsa_p_dup = BN_dup(dsa_p)) == NULL ||
-                   (dsa_q_dup = BN_dup(dsa_q)) == NULL ||
-                   (dsa_g_dup = BN_dup(dsa_g)) == NULL ||
-                   (dsa_pub_key_dup = BN_dup(dsa_pub_key)) == NULL) {
-                       r = SSH_ERR_ALLOC_FAIL;
-                       goto out;
-               }
-               if (!DSA_set0_pqg(n->dsa, dsa_p_dup, dsa_q_dup, dsa_g_dup)) {
-                       r = SSH_ERR_LIBCRYPTO_ERROR;
-                       goto out;
-               }
-               dsa_p_dup = dsa_q_dup = dsa_g_dup = NULL; /* transferred */
-               if (!DSA_set0_key(n->dsa, dsa_pub_key_dup, NULL)) {
-                       r = SSH_ERR_LIBCRYPTO_ERROR;
-                       goto out;
-               }
-               dsa_pub_key_dup = NULL; /* transferred */
-
-               break;
-       case KEY_ECDSA:
-       case KEY_ECDSA_CERT:
-       case KEY_ECDSA_SK:
-       case KEY_ECDSA_SK_CERT:
-               n->ecdsa_nid = k->ecdsa_nid;
-               n->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
-               if (n->ecdsa == NULL) {
-                       r = SSH_ERR_ALLOC_FAIL;
-                       goto out;
-               }
-               if (EC_KEY_set_public_key(n->ecdsa,
-                   EC_KEY_get0_public_key(k->ecdsa)) != 1) {
-                       r = SSH_ERR_LIBCRYPTO_ERROR;
-                       goto out;
-               }
-               if (k->type != KEY_ECDSA_SK && k->type != KEY_ECDSA_SK_CERT)
-                       break;
-               /* Append security-key application string */
-               if ((n->sk_application = strdup(k->sk_application)) == NULL)
-                       goto out;
-               break;
-       case KEY_RSA:
-       case KEY_RSA_CERT:
-               RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
-               if ((rsa_n_dup = BN_dup(rsa_n)) == NULL ||
-                   (rsa_e_dup = BN_dup(rsa_e)) == NULL) {
-                       r = SSH_ERR_ALLOC_FAIL;
-                       goto out;
-               }
-               if (!RSA_set0_key(n->rsa, rsa_n_dup, rsa_e_dup, NULL)) {
-                       r = SSH_ERR_LIBCRYPTO_ERROR;
-                       goto out;
-               }
-               rsa_n_dup = rsa_e_dup = NULL; /* transferred */
-               break;
-#endif /* WITH_OPENSSL */
-       case KEY_ED25519:
-       case KEY_ED25519_CERT:
-       case KEY_ED25519_SK:
-       case KEY_ED25519_SK_CERT:
-               if (k->ed25519_pk != NULL) {
-                       if ((n->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
-                               r = SSH_ERR_ALLOC_FAIL;
-                               goto out;
-                       }
-                       memcpy(n->ed25519_pk, k->ed25519_pk, ED25519_PK_SZ);
-               }
-               if (k->type != KEY_ED25519_SK &&
-                   k->type != KEY_ED25519_SK_CERT)
-                       break;
-               /* Append security-key application string */
-               if ((n->sk_application = strdup(k->sk_application)) == NULL)
-                       goto out;
-               break;
-#ifdef WITH_XMSS
-       case KEY_XMSS:
-       case KEY_XMSS_CERT:
-               if ((r = sshkey_xmss_init(n, k->xmss_name)) != 0)
-                       goto out;
-               if (k->xmss_pk != NULL) {
-                       u_int32_t left;
-                       size_t pklen = sshkey_xmss_pklen(k);
-                       if (pklen == 0 || sshkey_xmss_pklen(n) != pklen) {
-                               r = SSH_ERR_INTERNAL_ERROR;
-                               goto out;
-                       }
-                       if ((n->xmss_pk = malloc(pklen)) == NULL) {
-                               r = SSH_ERR_ALLOC_FAIL;
-                               goto out;
-                       }
-                       memcpy(n->xmss_pk, k->xmss_pk, pklen);
-                       /* simulate number of signatures left on pubkey */
-                       left = sshkey_xmss_signatures_left(k);
-                       if (left)
-                               sshkey_xmss_enable_maxsign(n, left);
-               }
-               break;
-#endif /* WITH_XMSS */
-       default:
-               r = SSH_ERR_KEY_TYPE_UNKNOWN;
+       if ((r = impl->funcs->copy_public(k, n)) != 0)
                goto out;
-       }
        if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0)
                goto out;
        /* success */
@@ -1538,15 +1438,6 @@ sshkey_from_private(const struct sshkey *k, struct sshkey **pkp)
        r = 0;
  out:
        sshkey_free(n);
-#ifdef WITH_OPENSSL
-       BN_clear_free(rsa_n_dup);
-       BN_clear_free(rsa_e_dup);
-       BN_clear_free(dsa_p_dup);
-       BN_clear_free(dsa_q_dup);
-       BN_clear_free(dsa_g_dup);
-       BN_clear_free(dsa_pub_key_dup);
-#endif /* WITH_OPENSSL */
-
        return r;
 }
 

diff --git a/usr.bin/ssh/sshkey.h b/usr.bin/ssh/sshkey.h
index c90724a..899614d 100644 (file)
--- a/usr.bin/ssh/sshkey.h
+++ b/usr.bin/ssh/sshkey.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.h,v 1.56 2022/10/28 00:39:29 djm Exp $ */
+/* $OpenBSD: sshkey.h,v 1.57 2022/10/28 00:41:17 djm Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -166,6 +166,7 @@ struct sshkey_impl_funcs {
        int (*serialize_public)(const struct sshkey *, struct sshbuf *,
            const char *, enum sshkey_serialize_rep);
        int (*generate)(struct sshkey *, int);  /* optional */
+       int (*copy_public)(const struct sshkey *, struct sshkey *);
 };
 
 struct sshkey_impl {
@@ -307,6 +308,7 @@ void         sshkey_sig_details_free(struct sshkey_sig_details *);
 int    sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b);
 void   sshkey_sk_cleanup(struct sshkey *k);
 int    sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b);
+int    sshkey_copy_public_sk(const struct sshkey *from, struct sshkey *to);
 
 int ssh_rsa_sign(const struct sshkey *key,
     u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,