/src/hpn-ssh/sshkey.c

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/* $OpenBSD: sshkey.c,v 1.142 2024/01/11 01:45:36 djm Exp $ */
/*
 * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
 * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
 * Copyright (c) 2010,2011 Damien Miller.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>
#include <netinet/in.h>

#ifdef WITH_OPENSSL
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#endif

#include "crypto_api.h"

#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <resolv.h>
#include <time.h>
#ifdef HAVE_UTIL_H
#include <util.h>
#endif /* HAVE_UTIL_H */

#include "ssh2.h"
#include "ssherr.h"
#include "misc.h"
#include "sshbuf.h"
#include "cipher.h"
#include "digest.h"
#define SSHKEY_INTERNAL
#include "sshkey.h"
#include "match.h"
#include "ssh-sk.h"

#ifdef WITH_XMSS
#include "sshkey-xmss.h"
#include "xmss_fast.h"
#endif

#include "openbsd-compat/openssl-compat.h"

/* openssh private key file format */
#define MARK_BEGIN    "-----BEGIN OPENSSH PRIVATE KEY-----\n"
#define MARK_END    "-----END OPENSSH PRIVATE KEY-----\n"
#define MARK_BEGIN_LEN    (sizeof(MARK_BEGIN) - 1)
#define MARK_END_LEN    (sizeof(MARK_END) - 1)
#define KDFNAME     "bcrypt"
#define AUTH_MAGIC    "openssh-key-v1"
#define SALT_LEN    16
#define DEFAULT_CIPHERNAME  "aes256-ctr"
#define DEFAULT_ROUNDS    24

/* Version identification string for SSH v1 identity files. */
#define LEGACY_BEGIN    "SSH PRIVATE KEY FILE FORMAT 1.1\n"

/*
 * Constants relating to "shielding" support; protection of keys expected
 * to remain in memory for long durations
 */
#define SSHKEY_SHIELD_PREKEY_LEN  (16 * 1024)
#define SSHKEY_SHIELD_CIPHER    "aes256-ctr" /* XXX want AES-EME* */
#define SSHKEY_SHIELD_PREKEY_HASH SSH_DIGEST_SHA512

int sshkey_private_serialize_opt(struct sshkey *key,
    struct sshbuf *buf, enum sshkey_serialize_rep);
static int sshkey_from_blob_internal(struct sshbuf *buf,
    struct sshkey **keyp, int allow_cert);

/* Supported key types */
extern const struct sshkey_impl sshkey_ed25519_impl;
extern const struct sshkey_impl sshkey_ed25519_cert_impl;
extern const struct sshkey_impl sshkey_ed25519_sk_impl;
extern const struct sshkey_impl sshkey_ed25519_sk_cert_impl;
#ifdef WITH_OPENSSL
# ifdef OPENSSL_HAS_ECC
#  ifdef ENABLE_SK
extern const struct sshkey_impl sshkey_ecdsa_sk_impl;
extern const struct sshkey_impl sshkey_ecdsa_sk_cert_impl;
extern const struct sshkey_impl sshkey_ecdsa_sk_webauthn_impl;
#  endif /* ENABLE_SK */
extern const struct sshkey_impl sshkey_ecdsa_nistp256_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp256_cert_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp384_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp384_cert_impl;
#  ifdef OPENSSL_HAS_NISTP521
extern const struct sshkey_impl sshkey_ecdsa_nistp521_impl;
extern const struct sshkey_impl sshkey_ecdsa_nistp521_cert_impl;
#  endif /* OPENSSL_HAS_NISTP521 */
# endif /* OPENSSL_HAS_ECC */
extern const struct sshkey_impl sshkey_rsa_impl;
extern const struct sshkey_impl sshkey_rsa_cert_impl;
extern const struct sshkey_impl sshkey_rsa_sha256_impl;
extern const struct sshkey_impl sshkey_rsa_sha256_cert_impl;
extern const struct sshkey_impl sshkey_rsa_sha512_impl;
extern const struct sshkey_impl sshkey_rsa_sha512_cert_impl;
# ifdef WITH_DSA
extern const struct sshkey_impl sshkey_dss_impl;
extern const struct sshkey_impl sshkey_dsa_cert_impl;
# endif
#endif /* WITH_OPENSSL */
#ifdef WITH_XMSS
extern const struct sshkey_impl sshkey_xmss_impl;
extern const struct sshkey_impl sshkey_xmss_cert_impl;
#endif

const struct sshkey_impl * const keyimpls[] = {
  &sshkey_ed25519_impl,
  &sshkey_ed25519_cert_impl,
#ifdef ENABLE_SK
  &sshkey_ed25519_sk_impl,
  &sshkey_ed25519_sk_cert_impl,
#endif
#ifdef WITH_OPENSSL
# ifdef OPENSSL_HAS_ECC
  &sshkey_ecdsa_nistp256_impl,
  &sshkey_ecdsa_nistp256_cert_impl,
  &sshkey_ecdsa_nistp384_impl,
  &sshkey_ecdsa_nistp384_cert_impl,
#  ifdef OPENSSL_HAS_NISTP521
  &sshkey_ecdsa_nistp521_impl,
  &sshkey_ecdsa_nistp521_cert_impl,
#  endif /* OPENSSL_HAS_NISTP521 */
#  ifdef ENABLE_SK
  &sshkey_ecdsa_sk_impl,
  &sshkey_ecdsa_sk_cert_impl,
  &sshkey_ecdsa_sk_webauthn_impl,
#  endif /* ENABLE_SK */
# endif /* OPENSSL_HAS_ECC */
# ifdef WITH_DSA
  &sshkey_dss_impl,
  &sshkey_dsa_cert_impl,
# endif
  &sshkey_rsa_impl,
  &sshkey_rsa_cert_impl,
  &sshkey_rsa_sha256_impl,
  &sshkey_rsa_sha256_cert_impl,
  &sshkey_rsa_sha512_impl,
  &sshkey_rsa_sha512_cert_impl,
#endif /* WITH_OPENSSL */
#ifdef WITH_XMSS
  &sshkey_xmss_impl,
  &sshkey_xmss_cert_impl,
#endif
  NULL
};

static const struct sshkey_impl *
sshkey_impl_from_type(int type)
{
  int i;

  for (i = 0; keyimpls[i] != NULL; i++) {
    if (keyimpls[i]->type == type)
      return keyimpls[i];
  }
  return NULL;
}

static const struct sshkey_impl *
sshkey_impl_from_type_nid(int type, int nid)
{
  int i;

  for (i = 0; keyimpls[i] != NULL; i++) {
    if (keyimpls[i]->type == type &&
        (keyimpls[i]->nid == 0 || keyimpls[i]->nid == nid))
      return keyimpls[i];
  }
  return NULL;
}

static const struct sshkey_impl *
sshkey_impl_from_key(const struct sshkey *k)
{
  if (k == NULL)
    return NULL;
  return sshkey_impl_from_type_nid(k->type, k->ecdsa_nid);
}

const char *
sshkey_type(const struct sshkey *k)
{
  const struct sshkey_impl *impl;

  if ((impl = sshkey_impl_from_key(k)) == NULL)
    return "unknown";
  return impl->shortname;
}

static const char *
sshkey_ssh_name_from_type_nid(int type, int nid)
{
  const struct sshkey_impl *impl;

  if ((impl = sshkey_impl_from_type_nid(type, nid)) == NULL)
    return "ssh-unknown";
  return impl->name;
}

int
sshkey_type_is_cert(int type)
{
  const struct sshkey_impl *impl;

  if ((impl = sshkey_impl_from_type(type)) == NULL)
    return 0;
  return impl->cert;
}

const char *
sshkey_ssh_name(const struct sshkey *k)
{
  return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid);
}

const char *
sshkey_ssh_name_plain(const struct sshkey *k)
{
  return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type),
      k->ecdsa_nid);
}

int
sshkey_type_from_name(const char *name)
{
  int i;
  const struct sshkey_impl *impl;

  for (i = 0; keyimpls[i] != NULL; i++) {
    impl = keyimpls[i];
    /* Only allow shortname matches for plain key types */
    if ((impl->name != NULL && strcmp(name, impl->name) == 0) ||
        (!impl->cert && strcasecmp(impl->shortname, name) == 0))
      return impl->type;
  }
  return KEY_UNSPEC;
}

static int
key_type_is_ecdsa_variant(int type)
{
  switch (type) {
  case KEY_ECDSA:
  case KEY_ECDSA_CERT:
  case KEY_ECDSA_SK:
  case KEY_ECDSA_SK_CERT:
    return 1;
  }
  return 0;
}

int
sshkey_ecdsa_nid_from_name(const char *name)
{
  int i;

  for (i = 0; keyimpls[i] != NULL; i++) {
    if (!key_type_is_ecdsa_variant(keyimpls[i]->type))
      continue;
    if (keyimpls[i]->name != NULL &&
        strcmp(name, keyimpls[i]->name) == 0)
      return keyimpls[i]->nid;
  }
  return -1;
}

int
sshkey_match_keyname_to_sigalgs(const char *keyname, const char *sigalgs)
{
  int ktype;

  if (sigalgs == NULL || *sigalgs == '\0' ||
      (ktype = sshkey_type_from_name(keyname)) == KEY_UNSPEC)
    return 0;
  else if (ktype == KEY_RSA) {
    return match_pattern_list("ssh-rsa", sigalgs, 0) == 1 ||
        match_pattern_list("rsa-sha2-256", sigalgs, 0) == 1 ||
        match_pattern_list("rsa-sha2-512", sigalgs, 0) == 1;
  } else if (ktype == KEY_RSA_CERT) {
    return match_pattern_list("ssh-rsa-cert-v01@openssh.com",
        sigalgs, 0) == 1 ||
        match_pattern_list("rsa-sha2-256-cert-v01@openssh.com",
        sigalgs, 0) == 1 ||
        match_pattern_list("rsa-sha2-512-cert-v01@openssh.com",
        sigalgs, 0) == 1;
  } else
    return match_pattern_list(keyname, sigalgs, 0) == 1;
}

char *
sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
{
  char *tmp, *ret = NULL;
  size_t i, nlen, rlen = 0;
  const struct sshkey_impl *impl;

  for (i = 0; keyimpls[i] != NULL; i++) {
    impl = keyimpls[i];
    if (impl->name == NULL)
      continue;
    if (!include_sigonly && impl->sigonly)
      continue;
    if ((certs_only && !impl->cert) || (plain_only && impl->cert))
      continue;
    if (ret != NULL)
      ret[rlen++] = sep;
    nlen = strlen(impl->name);
    if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
      free(ret);
      return NULL;
    }
    ret = tmp;
    memcpy(ret + rlen, impl->name, nlen + 1);
    rlen += nlen;
  }
  return ret;
}

int
sshkey_names_valid2(const char *names, int allow_wildcard, int plain_only)
{
  char *s, *cp, *p;
  const struct sshkey_impl *impl;
  int i, type;

  if (names == NULL || strcmp(names, "") == 0)
    return 0;
  if ((s = cp = strdup(names)) == NULL)
    return 0;
  for ((p = strsep(&cp, ",")); p && *p != '\0';
      (p = strsep(&cp, ","))) {
    type = sshkey_type_from_name(p);
    if (type == KEY_UNSPEC) {
      if (allow_wildcard) {
        /*
         * Try matching key types against the string.
         * If any has a positive or negative match then
         * the component is accepted.
         */
        impl = NULL;
        for (i = 0; keyimpls[i] != NULL; i++) {
          if (match_pattern_list(
              keyimpls[i]->name, p, 0) != 0) {
            impl = keyimpls[i];
            break;
          }
        }
        if (impl != NULL)
          continue;
      }
      free(s);
      return 0;
    } else if (plain_only && sshkey_type_is_cert(type)) {
      free(s);
      return 0;
    }
  }
  free(s);
  return 1;
}

u_int
sshkey_size(const struct sshkey *k)
{
  const struct sshkey_impl *impl;

  if ((impl = sshkey_impl_from_key(k)) == NULL)
    return 0;
  if (impl->funcs->size != NULL)
    return impl->funcs->size(k);
  return impl->keybits;
}

static int
sshkey_type_is_valid_ca(int type)
{
  const struct sshkey_impl *impl;

  if ((impl = sshkey_impl_from_type(type)) == NULL)
    return 0;
  /* All non-certificate types may act as CAs */
  return !impl->cert;
}

int
sshkey_is_cert(const struct sshkey *k)
{
  if (k == NULL)
    return 0;
  return sshkey_type_is_cert(k->type);
}

int
sshkey_is_sk(const struct sshkey *k)
{
  if (k == NULL)
    return 0;
  switch (sshkey_type_plain(k->type)) {
  case KEY_ECDSA_SK:
  case KEY_ED25519_SK:
    return 1;
  default:
    return 0;
  }
}

/* Return the cert-less equivalent to a certified key type */
int
sshkey_type_plain(int type)
{
  switch (type) {
  case KEY_RSA_CERT:
    return KEY_RSA;
  case KEY_DSA_CERT:
    return KEY_DSA;
  case KEY_ECDSA_CERT:
    return KEY_ECDSA;
  case KEY_ECDSA_SK_CERT:
    return KEY_ECDSA_SK;
  case KEY_ED25519_CERT:
    return KEY_ED25519;
  case KEY_ED25519_SK_CERT:
    return KEY_ED25519_SK;
  case KEY_XMSS_CERT:
    return KEY_XMSS;
  default:
    return type;
  }
}

/* Return the cert equivalent to a plain key type */
static int
sshkey_type_certified(int type)
{
  switch (type) {
  case KEY_RSA:
    return KEY_RSA_CERT;
  case KEY_DSA:
    return KEY_DSA_CERT;
  case KEY_ECDSA:
    return KEY_ECDSA_CERT;
  case KEY_ECDSA_SK:
    return KEY_ECDSA_SK_CERT;
  case KEY_ED25519:
    return KEY_ED25519_CERT;
  case KEY_ED25519_SK:
    return KEY_ED25519_SK_CERT;
  case KEY_XMSS:
    return KEY_XMSS_CERT;
  default:
    return -1;
  }
}

#ifdef WITH_OPENSSL
/* XXX: these are really begging for a table-driven approach */
int
sshkey_curve_name_to_nid(const char *name)
{
  if (strcmp(name, "nistp256") == 0)
    return NID_X9_62_prime256v1;
  else if (strcmp(name, "nistp384") == 0)
    return NID_secp384r1;
# ifdef OPENSSL_HAS_NISTP521
  else if (strcmp(name, "nistp521") == 0)
    return NID_secp521r1;
# endif /* OPENSSL_HAS_NISTP521 */
  else
    return -1;
}

u_int
sshkey_curve_nid_to_bits(int nid)
{
  switch (nid) {
  case NID_X9_62_prime256v1:
    return 256;
  case NID_secp384r1:
    return 384;
# ifdef OPENSSL_HAS_NISTP521
  case NID_secp521r1:
    return 521;
# endif /* OPENSSL_HAS_NISTP521 */
  default:
    return 0;
  }
}

int
sshkey_ecdsa_bits_to_nid(int bits)
{
  switch (bits) {
  case 256:
    return NID_X9_62_prime256v1;
  case 384:
    return NID_secp384r1;
# ifdef OPENSSL_HAS_NISTP521
  case 521:
    return NID_secp521r1;
# endif /* OPENSSL_HAS_NISTP521 */
  default:
    return -1;
  }
}

const char *
sshkey_curve_nid_to_name(int nid)
{
  switch (nid) {
  case NID_X9_62_prime256v1:
    return "nistp256";
  case NID_secp384r1:
    return "nistp384";
# ifdef OPENSSL_HAS_NISTP521
  case NID_secp521r1:
    return "nistp521";
# endif /* OPENSSL_HAS_NISTP521 */
  default:
    return NULL;
  }
}

int
sshkey_ec_nid_to_hash_alg(int nid)
{
  int kbits = sshkey_curve_nid_to_bits(nid);

  if (kbits <= 0)
    return -1;

  /* RFC5656 section 6.2.1 */
  if (kbits <= 256)
    return SSH_DIGEST_SHA256;
  else if (kbits <= 384)
    return SSH_DIGEST_SHA384;
  else
    return SSH_DIGEST_SHA512;
}
#endif /* WITH_OPENSSL */

static void
cert_free(struct sshkey_cert *cert)
{
  u_int i;

  if (cert == NULL)
    return;
  sshbuf_free(cert->certblob);
  sshbuf_free(cert->critical);
  sshbuf_free(cert->extensions);
  free(cert->key_id);
  for (i = 0; i < cert->nprincipals; i++)
    free(cert->principals[i]);
  free(cert->principals);
  sshkey_free(cert->signature_key);
  free(cert->signature_type);
  freezero(cert, sizeof(*cert));
}

static struct sshkey_cert *
cert_new(void)
{
  struct sshkey_cert *cert;

  if ((cert = calloc(1, sizeof(*cert))) == NULL)
    return NULL;
  if ((cert->certblob = sshbuf_new()) == NULL ||
      (cert->critical = sshbuf_new()) == NULL ||
      (cert->extensions = sshbuf_new()) == NULL) {
    cert_free(cert);
    return NULL;
  }
  cert->key_id = NULL;
  cert->principals = NULL;
  cert->signature_key = NULL;
  cert->signature_type = NULL;
  return cert;
}

struct sshkey *
sshkey_new(int type)
{
  struct sshkey *k;
  const struct sshkey_impl *impl = NULL;

  if (type != KEY_UNSPEC &&
      (impl = sshkey_impl_from_type(type)) == NULL)
    return NULL;

  /* All non-certificate types may act as CAs */
  if ((k = calloc(1, sizeof(*k))) == NULL)
    return NULL;
  k->type = type;
  k->ecdsa_nid = -1;
  if (impl != NULL && impl->funcs->alloc != NULL) {
    if (impl->funcs->alloc(k) != 0) {
      free(k);
      return NULL;
    }
  }
  if (sshkey_is_cert(k)) {
    if ((k->cert = cert_new()) == NULL) {
      sshkey_free(k);
      return NULL;
    }
  }

  return k;
}

/* Frees common FIDO fields */
void
sshkey_sk_cleanup(struct sshkey *k)
{
  free(k->sk_application);
  sshbuf_free(k->sk_key_handle);
  sshbuf_free(k->sk_reserved);
  k->sk_application = NULL;
  k->sk_key_handle = k->sk_reserved = NULL;
}

static void
sshkey_free_contents(struct sshkey *k)
{
  const struct sshkey_impl *impl;

  if (k == NULL)
    return;
  if ((impl = sshkey_impl_from_type(k->type)) != NULL &&
      impl->funcs->cleanup != NULL)
    impl->funcs->cleanup(k);
  if (sshkey_is_cert(k))
    cert_free(k->cert);
  freezero(k->shielded_private, k->shielded_len);
  freezero(k->shield_prekey, k->shield_prekey_len);
}

void
sshkey_free(struct sshkey *k)
{
  sshkey_free_contents(k);
  freezero(k, sizeof(*k));
}

static int
cert_compare(struct sshkey_cert *a, struct sshkey_cert *b)
{
  if (a == NULL && b == NULL)
    return 1;
  if (a == NULL || b == NULL)
    return 0;
  if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob))
    return 0;
  if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob),
      sshbuf_len(a->certblob)) != 0)
    return 0;
  return 1;
}

/* Compares FIDO-specific pubkey fields only */
int
sshkey_sk_fields_equal(const struct sshkey *a, const struct sshkey *b)
{
  if (a->sk_application == NULL || b->sk_application == NULL)
    return 0;
  if (strcmp(a->sk_application, b->sk_application) != 0)
    return 0;
  return 1;
}

/*
 * Compare public portions of key only, allowing comparisons between
 * certificates and plain keys too.
 */
int
sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
{
  const struct sshkey_impl *impl;

  if (a == NULL || b == NULL ||
      sshkey_type_plain(a->type) != sshkey_type_plain(b->type))
    return 0;
  if ((impl = sshkey_impl_from_type(a->type)) == NULL)
    return 0;
  return impl->funcs->equal(a, b);
}

int
sshkey_equal(const struct sshkey *a, const struct sshkey *b)
{
  if (a == NULL || b == NULL || a->type != b->type)
    return 0;
  if (sshkey_is_cert(a)) {
    if (!cert_compare(a->cert, b->cert))
      return 0;
  }
  return sshkey_equal_public(a, b);
}


/* Serialise common FIDO key parts */
int
sshkey_serialize_sk(const struct sshkey *key, struct sshbuf *b)
{
  int r;

  if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0)
    return r;

  return 0;
}

static int
to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain,
  enum sshkey_serialize_rep opts)
{
  int type, ret = SSH_ERR_INTERNAL_ERROR;
  const char *typename;
  const struct sshkey_impl *impl;

  if (key == NULL)
    return SSH_ERR_INVALID_ARGUMENT;

  type = force_plain ? sshkey_type_plain(key->type) : key->type;

  if (sshkey_type_is_cert(type)) {
    if (key->cert == NULL)
      return SSH_ERR_EXPECTED_CERT;
    if (sshbuf_len(key->cert->certblob) == 0)
      return SSH_ERR_KEY_LACKS_CERTBLOB;
    /* Use the existing blob */
    if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0)
      return ret;
    return 0;
  }
  if ((impl = sshkey_impl_from_type(type)) == NULL)
    return SSH_ERR_KEY_TYPE_UNKNOWN;

  typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid);
  if ((ret = sshbuf_put_cstring(b, typename)) != 0)
    return ret;
  return impl->funcs->serialize_public(key, b, opts);
}

int
sshkey_putb(const struct sshkey *key, struct sshbuf *b)
{
  return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT);
}

int
sshkey_puts_opts(const struct sshkey *key, struct sshbuf *b,
    enum sshkey_serialize_rep opts)
{
  struct sshbuf *tmp;
  int r;

  if ((tmp = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  r = to_blob_buf(key, tmp, 0, opts);
  if (r == 0)
    r = sshbuf_put_stringb(b, tmp);
  sshbuf_free(tmp);
  return r;
}

int
sshkey_puts(const struct sshkey *key, struct sshbuf *b)
{
  return sshkey_puts_opts(key, b, SSHKEY_SERIALIZE_DEFAULT);
}

int
sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b)
{
  return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT);
}

static int
to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain,
    enum sshkey_serialize_rep opts)
{
  int ret = SSH_ERR_INTERNAL_ERROR;
  size_t len;
  struct sshbuf *b = NULL;

  if (lenp != NULL)
    *lenp = 0;
  if (blobp != NULL)
    *blobp = NULL;
  if ((b = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0)
    goto out;
  len = sshbuf_len(b);
  if (lenp != NULL)
    *lenp = len;
  if (blobp != NULL) {
    if ((*blobp = malloc(len)) == NULL) {
      ret = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    memcpy(*blobp, sshbuf_ptr(b), len);
  }
  ret = 0;
 out:
  sshbuf_free(b);
  return ret;
}

int
sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
{
  return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT);
}

int
sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
{
  return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT);
}

int
sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg,
    u_char **retp, size_t *lenp)
{
  u_char *blob = NULL, *ret = NULL;
  size_t blob_len = 0;
  int r = SSH_ERR_INTERNAL_ERROR;

  if (retp != NULL)
    *retp = NULL;
  if (lenp != NULL)
    *lenp = 0;
  if (ssh_digest_bytes(dgst_alg) == 0) {
    r = SSH_ERR_INVALID_ARGUMENT;
    goto out;
  }
  if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT))
      != 0)
    goto out;
  if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if ((r = ssh_digest_memory(dgst_alg, blob, blob_len,
      ret, SSH_DIGEST_MAX_LENGTH)) != 0)
    goto out;
  /* success */
  if (retp != NULL) {
    *retp = ret;
    ret = NULL;
  }
  if (lenp != NULL)
    *lenp = ssh_digest_bytes(dgst_alg);
  r = 0;
 out:
  free(ret);
  if (blob != NULL)
    freezero(blob, blob_len);
  return r;
}

static char *
fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
{
  char *ret;
  size_t plen = strlen(alg) + 1;
  size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1;

  if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL)
    return NULL;
  strlcpy(ret, alg, rlen);
  strlcat(ret, ":", rlen);
  if (dgst_raw_len == 0)
    return ret;
  if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) {
    freezero(ret, rlen);
    return NULL;
  }
  /* Trim padding characters from end */
  ret[strcspn(ret, "=")] = '\0';
  return ret;
}

static char *
fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
{
  char *retval, hex[5];
  size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2;

  if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL)
    return NULL;
  strlcpy(retval, alg, rlen);
  strlcat(retval, ":", rlen);
  for (i = 0; i < dgst_raw_len; i++) {
    snprintf(hex, sizeof(hex), "%s%02x",
        i > 0 ? ":" : "", dgst_raw[i]);
    strlcat(retval, hex, rlen);
  }
  return retval;
}

static char *
fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len)
{
  char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
  char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
      'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
  u_int i, j = 0, rounds, seed = 1;
  char *retval;

  rounds = (dgst_raw_len / 2) + 1;
  if ((retval = calloc(rounds, 6)) == NULL)
    return NULL;
  retval[j++] = 'x';
  for (i = 0; i < rounds; i++) {
    u_int idx0, idx1, idx2, idx3, idx4;
    if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
      idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
          seed) % 6;
      idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
      idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
          (seed / 6)) % 6;
      retval[j++] = vowels[idx0];
      retval[j++] = consonants[idx1];
      retval[j++] = vowels[idx2];
      if ((i + 1) < rounds) {
        idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
        idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
        retval[j++] = consonants[idx3];
        retval[j++] = '-';
        retval[j++] = consonants[idx4];
        seed = ((seed * 5) +
            ((((u_int)(dgst_raw[2 * i])) * 7) +
            ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
      }
    } else {
      idx0 = seed % 6;
      idx1 = 16;
      idx2 = seed / 6;
      retval[j++] = vowels[idx0];
      retval[j++] = consonants[idx1];
      retval[j++] = vowels[idx2];
    }
  }
  retval[j++] = 'x';
  retval[j++] = '\0';
  return retval;
}

/*
 * Draw an ASCII-Art representing the fingerprint so human brain can
 * profit from its built-in pattern recognition ability.
 * This technique is called "random art" and can be found in some
 * scientific publications like this original paper:
 *
 * "Hash Visualization: a New Technique to improve Real-World Security",
 * Perrig A. and Song D., 1999, International Workshop on Cryptographic
 * Techniques and E-Commerce (CrypTEC '99)
 * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
 *
 * The subject came up in a talk by Dan Kaminsky, too.
 *
 * If you see the picture is different, the key is different.
 * If the picture looks the same, you still know nothing.
 *
 * The algorithm used here is a worm crawling over a discrete plane,
 * leaving a trace (augmenting the field) everywhere it goes.
 * Movement is taken from dgst_raw 2bit-wise.  Bumping into walls
 * makes the respective movement vector be ignored for this turn.
 * Graphs are not unambiguous, because circles in graphs can be
 * walked in either direction.
 */

/*
 * Field sizes for the random art.  Have to be odd, so the starting point
 * can be in the exact middle of the picture, and FLDBASE should be >=8 .
 * Else pictures would be too dense, and drawing the frame would
 * fail, too, because the key type would not fit in anymore.
 */
#define FLDBASE   8
#define FLDSIZE_Y (FLDBASE + 1)
#define FLDSIZE_X (FLDBASE * 2 + 1)
static char *
fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len,
    const struct sshkey *k)
{
  /*
   * Chars to be used after each other every time the worm
   * intersects with itself.  Matter of taste.
   */
  char  *augmentation_string = " .o+=*BOX@%&#/^SE";
  char  *retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X];
  u_char   field[FLDSIZE_X][FLDSIZE_Y];
  size_t   i, tlen, hlen;
  u_int  b;
  int  x, y, r;
  size_t   len = strlen(augmentation_string) - 1;

  if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL)
    return NULL;

  /* initialize field */
  memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
  x = FLDSIZE_X / 2;
  y = FLDSIZE_Y / 2;

  /* process raw key */
  for (i = 0; i < dgst_raw_len; i++) {
    int input;
    /* each byte conveys four 2-bit move commands */
    input = dgst_raw[i];
    for (b = 0; b < 4; b++) {
      /* evaluate 2 bit, rest is shifted later */
      x += (input & 0x1) ? 1 : -1;
      y += (input & 0x2) ? 1 : -1;

      /* assure we are still in bounds */
      x = MAXIMUM(x, 0);
      y = MAXIMUM(y, 0);
      x = MINIMUM(x, FLDSIZE_X - 1);
      y = MINIMUM(y, FLDSIZE_Y - 1);

      /* augment the field */
      if (field[x][y] < len - 2)
        field[x][y]++;
      input = input >> 2;
    }
  }

  /* mark starting point and end point*/
  field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
  field[x][y] = len;

  /* assemble title */
  r = snprintf(title, sizeof(title), "[%s %u]",
    sshkey_type(k), sshkey_size(k));
  /* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */
  if (r < 0 || r > (int)sizeof(title))
    r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k));
  tlen = (r <= 0) ? 0 : strlen(title);

  /* assemble hash ID. */
  r = snprintf(hash, sizeof(hash), "[%s]", alg);
  hlen = (r <= 0) ? 0 : strlen(hash);

  /* output upper border */
  p = retval;
  *p++ = '+';
  for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++)
    *p++ = '-';
  memcpy(p, title, tlen);
  p += tlen;
  for (i += tlen; i < FLDSIZE_X; i++)
    *p++ = '-';
  *p++ = '+';
  *p++ = '\n';

  /* output content */
  for (y = 0; y < FLDSIZE_Y; y++) {
    *p++ = '|';
    for (x = 0; x < FLDSIZE_X; x++)
      *p++ = augmentation_string[MINIMUM(field[x][y], len)];
    *p++ = '|';
    *p++ = '\n';
  }

  /* output lower border */
  *p++ = '+';
  for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++)
    *p++ = '-';
  memcpy(p, hash, hlen);
  p += hlen;
  for (i += hlen; i < FLDSIZE_X; i++)
    *p++ = '-';
  *p++ = '+';

  return retval;
}

char *
sshkey_fingerprint(const struct sshkey *k, int dgst_alg,
    enum sshkey_fp_rep dgst_rep)
{
  char *retval = NULL;
  u_char *dgst_raw;
  size_t dgst_raw_len;

  if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0)
    return NULL;
  switch (dgst_rep) {
  case SSH_FP_DEFAULT:
    if (dgst_alg == SSH_DIGEST_MD5) {
      retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
          dgst_raw, dgst_raw_len);
    } else {
      retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
          dgst_raw, dgst_raw_len);
    }
    break;
  case SSH_FP_HEX:
    retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
        dgst_raw, dgst_raw_len);
    break;
  case SSH_FP_BASE64:
    retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
        dgst_raw, dgst_raw_len);
    break;
  case SSH_FP_BUBBLEBABBLE:
    retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
    break;
  case SSH_FP_RANDOMART:
    retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg),
        dgst_raw, dgst_raw_len, k);
    break;
  default:
    freezero(dgst_raw, dgst_raw_len);
    return NULL;
  }
  freezero(dgst_raw, dgst_raw_len);
  return retval;
}

static int
peek_type_nid(const char *s, size_t l, int *nid)
{
  const struct sshkey_impl *impl;
  int i;

  for (i = 0; keyimpls[i] != NULL; i++) {
    impl = keyimpls[i];
    if (impl->name == NULL || strlen(impl->name) != l)
      continue;
    if (memcmp(s, impl->name, l) == 0) {
      *nid = -1;
      if (key_type_is_ecdsa_variant(impl->type))
        *nid = impl->nid;
      return impl->type;
    }
  }
  return KEY_UNSPEC;
}

/* XXX this can now be made const char * */
int
sshkey_read(struct sshkey *ret, char **cpp)
{
  struct sshkey *k;
  char *cp, *blobcopy;
  size_t space;
  int r, type, curve_nid = -1;
  struct sshbuf *blob;

  if (ret == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if (ret->type != KEY_UNSPEC && sshkey_impl_from_type(ret->type) == NULL)
    return SSH_ERR_INVALID_ARGUMENT;

  /* Decode type */
  cp = *cpp;
  space = strcspn(cp, " \t");
  if (space == strlen(cp))
    return SSH_ERR_INVALID_FORMAT;
  if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC)
    return SSH_ERR_INVALID_FORMAT;

  /* skip whitespace */
  for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
    ;
  if (*cp == '\0')
    return SSH_ERR_INVALID_FORMAT;
  if (ret->type != KEY_UNSPEC && ret->type != type)
    return SSH_ERR_KEY_TYPE_MISMATCH;
  if ((blob = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;

  /* find end of keyblob and decode */
  space = strcspn(cp, " \t");
  if ((blobcopy = strndup(cp, space)) == NULL) {
    sshbuf_free(blob);
    return SSH_ERR_ALLOC_FAIL;
  }
  if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) {
    free(blobcopy);
    sshbuf_free(blob);
    return r;
  }
  free(blobcopy);
  if ((r = sshkey_fromb(blob, &k)) != 0) {
    sshbuf_free(blob);
    return r;
  }
  sshbuf_free(blob);

  /* skip whitespace and leave cp at start of comment */
  for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
    ;

  /* ensure type of blob matches type at start of line */
  if (k->type != type) {
    sshkey_free(k);
    return SSH_ERR_KEY_TYPE_MISMATCH;
  }
  if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) {
    sshkey_free(k);
    return SSH_ERR_EC_CURVE_MISMATCH;
  }

  /* Fill in ret from parsed key */
  sshkey_free_contents(ret);
  *ret = *k;
  freezero(k, sizeof(*k));

  /* success */
  *cpp = cp;
  return 0;
}

int
sshkey_to_base64(const struct sshkey *key, char **b64p)
{
  int r = SSH_ERR_INTERNAL_ERROR;
  struct sshbuf *b = NULL;
  char *uu = NULL;

  if (b64p != NULL)
    *b64p = NULL;
  if ((b = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((r = sshkey_putb(key, b)) != 0)
    goto out;
  if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  /* Success */
  if (b64p != NULL) {
    *b64p = uu;
    uu = NULL;
  }
  r = 0;
 out:
  sshbuf_free(b);
  free(uu);
  return r;
}

int
sshkey_format_text(const struct sshkey *key, struct sshbuf *b)
{
  int r = SSH_ERR_INTERNAL_ERROR;
  char *uu = NULL;

  if ((r = sshkey_to_base64(key, &uu)) != 0)
    goto out;
  if ((r = sshbuf_putf(b, "%s %s",
      sshkey_ssh_name(key), uu)) != 0)
    goto out;
  r = 0;
 out:
  free(uu);
  return r;
}

int
sshkey_write(const struct sshkey *key, FILE *f)
{
  struct sshbuf *b = NULL;
  int r = SSH_ERR_INTERNAL_ERROR;

  if ((b = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((r = sshkey_format_text(key, b)) != 0)
    goto out;
  if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) {
    if (feof(f))
      errno = EPIPE;
    r = SSH_ERR_SYSTEM_ERROR;
    goto out;
  }
  /* Success */
  r = 0;
 out:
  sshbuf_free(b);
  return r;
}

const char *
sshkey_cert_type(const struct sshkey *k)
{
  switch (k->cert->type) {
  case SSH2_CERT_TYPE_USER:
    return "user";
  case SSH2_CERT_TYPE_HOST:
    return "host";
  default:
    return "unknown";
  }
}

int
sshkey_check_rsa_length(const struct sshkey *k, int min_size)
{
#ifdef WITH_OPENSSL
  const BIGNUM *rsa_n;
  int nbits;

  if (k == NULL || k->rsa == NULL ||
      (k->type != KEY_RSA && k->type != KEY_RSA_CERT))
    return 0;
  RSA_get0_key(k->rsa, &rsa_n, NULL, NULL);
  nbits = BN_num_bits(rsa_n);
  if (nbits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
      (min_size > 0 && nbits < min_size))
    return SSH_ERR_KEY_LENGTH;
#endif /* WITH_OPENSSL */
  return 0;
}

#ifdef WITH_OPENSSL
# ifdef OPENSSL_HAS_ECC
int
sshkey_ecdsa_key_to_nid(EC_KEY *k)
{
  EC_GROUP *eg;
  int nids[] = {
    NID_X9_62_prime256v1,
    NID_secp384r1,
#  ifdef OPENSSL_HAS_NISTP521
    NID_secp521r1,
#  endif /* OPENSSL_HAS_NISTP521 */
    -1
  };
  int nid;
  u_int i;
  const EC_GROUP *g = EC_KEY_get0_group(k);

  /*
   * The group may be stored in a ASN.1 encoded private key in one of two
   * ways: as a "named group", which is reconstituted by ASN.1 object ID
   * or explicit group parameters encoded into the key blob. Only the
   * "named group" case sets the group NID for us, but we can figure
   * it out for the other case by comparing against all the groups that
   * are supported.
   */
  if ((nid = EC_GROUP_get_curve_name(g)) > 0)
    return nid;
  for (i = 0; nids[i] != -1; i++) {
    if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
      return -1;
    if (EC_GROUP_cmp(g, eg, NULL) == 0)
      break;
    EC_GROUP_free(eg);
  }
  if (nids[i] != -1) {
    /* Use the group with the NID attached */
    EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE);
    if (EC_KEY_set_group(k, eg) != 1) {
      EC_GROUP_free(eg);
      return -1;
    }
  }
  return nids[i];
}
# endif /* OPENSSL_HAS_ECC */
#endif /* WITH_OPENSSL */

int
sshkey_generate(int type, u_int bits, struct sshkey **keyp)
{
  struct sshkey *k;
  int ret = SSH_ERR_INTERNAL_ERROR;
  const struct sshkey_impl *impl;

  if (keyp == NULL || sshkey_type_is_cert(type))
    return SSH_ERR_INVALID_ARGUMENT;
  *keyp = NULL;
  if ((impl = sshkey_impl_from_type(type)) == NULL)
    return SSH_ERR_KEY_TYPE_UNKNOWN;
  if (impl->funcs->generate == NULL)
    return SSH_ERR_FEATURE_UNSUPPORTED;
  if ((k = sshkey_new(KEY_UNSPEC)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  k->type = type;
  if ((ret = impl->funcs->generate(k, bits)) != 0) {
    sshkey_free(k);
    return ret;
  }
  /* success */
  *keyp = k;
  return 0;
}

int
sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key)
{
  u_int i;
  const struct sshkey_cert *from;
  struct sshkey_cert *to;
  int r = SSH_ERR_INTERNAL_ERROR;

  if (to_key == NULL || (from = from_key->cert) == NULL)
    return SSH_ERR_INVALID_ARGUMENT;

  if ((to = cert_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;

  if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 ||
      (r = sshbuf_putb(to->critical, from->critical)) != 0 ||
      (r = sshbuf_putb(to->extensions, from->extensions)) != 0)
    goto out;

  to->serial = from->serial;
  to->type = from->type;
  if (from->key_id == NULL)
    to->key_id = NULL;
  else if ((to->key_id = strdup(from->key_id)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  to->valid_after = from->valid_after;
  to->valid_before = from->valid_before;
  if (from->signature_key == NULL)
    to->signature_key = NULL;
  else if ((r = sshkey_from_private(from->signature_key,
      &to->signature_key)) != 0)
    goto out;
  if (from->signature_type != NULL &&
      (to->signature_type = strdup(from->signature_type)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) {
    r = SSH_ERR_INVALID_ARGUMENT;
    goto out;
  }
  if (from->nprincipals > 0) {
    if ((to->principals = calloc(from->nprincipals,
        sizeof(*to->principals))) == NULL) {
      r = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    for (i = 0; i < from->nprincipals; i++) {
      to->principals[i] = strdup(from->principals[i]);
      if (to->principals[i] == NULL) {
        to->nprincipals = i;
        r = SSH_ERR_ALLOC_FAIL;
        goto out;
      }
    }
  }
  to->nprincipals = from->nprincipals;

  /* success */
  cert_free(to_key->cert);
  to_key->cert = to;
  to = NULL;
  r = 0;
 out:
  cert_free(to);
  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;
  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;
  }
  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 */
  *pkp = n;
  n = NULL;
  r = 0;
 out:
  sshkey_free(n);
  return r;
}

int
sshkey_is_shielded(struct sshkey *k)
{
  return k != NULL && k->shielded_private != NULL;
}

int
sshkey_shield_private(struct sshkey *k)
{
  struct sshbuf *prvbuf = NULL;
  u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH];
  struct sshcipher_ctx *cctx = NULL;
  const struct sshcipher *cipher;
  size_t i, enclen = 0;
  struct sshkey *kswap = NULL, tmp;
  int r = SSH_ERR_INTERNAL_ERROR;

#ifdef DEBUG_PK
  fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
#endif
  if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
    r = SSH_ERR_INVALID_ARGUMENT;
    goto out;
  }
  if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
      ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
    r = SSH_ERR_INTERNAL_ERROR;
    goto out;
  }

  /* Prepare a random pre-key, and from it an ephemeral key */
  if ((prekey = malloc(SSHKEY_SHIELD_PREKEY_LEN)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN);
  if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
      prekey, SSHKEY_SHIELD_PREKEY_LEN,
      keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
    goto out;
#ifdef DEBUG_PK
  fprintf(stderr, "%s: key+iv\n", __func__);
  sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
      stderr);
#endif
  if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
      keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0,
      CIPHER_ENCRYPT, CIPHER_SERIAL)) != 0)
    goto out;

  /* Serialise and encrypt the private key using the ephemeral key */
  if ((prvbuf = sshbuf_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0)
    goto out;
  if ((r = sshkey_private_serialize_opt(k, prvbuf,
      SSHKEY_SERIALIZE_SHIELD)) != 0)
    goto out;
  /* pad to cipher blocksize */
  i = 0;
  while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) {
    if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0)
      goto out;
  }
#ifdef DEBUG_PK
  fprintf(stderr, "%s: serialised\n", __func__);
  sshbuf_dump(prvbuf, stderr);
#endif
  /* encrypt */
  enclen = sshbuf_len(prvbuf);
  if ((enc = malloc(enclen)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if ((r = cipher_crypt(cctx, 0, enc, sshbuf_ptr(prvbuf),
      sshbuf_len(prvbuf), 0, 0)) != 0)
    goto out;
#ifdef DEBUG_PK
  fprintf(stderr, "%s: encrypted\n", __func__);
  sshbuf_dump_data(enc, enclen, stderr);
#endif

  /* Make a scrubbed, public-only copy of our private key argument */
  if ((r = sshkey_from_private(k, &kswap)) != 0)
    goto out;

  /* Swap the private key out (it will be destroyed below) */
  tmp = *kswap;
  *kswap = *k;
  *k = tmp;

  /* Insert the shielded key into our argument */
  k->shielded_private = enc;
  k->shielded_len = enclen;
  k->shield_prekey = prekey;
  k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN;
  enc = prekey = NULL; /* transferred */
  enclen = 0;

  /* preserve key fields that are required for correct operation */
  k->sk_flags = kswap->sk_flags;

  /* success */
  r = 0;

 out:
  /* XXX behaviour on error - invalidate original private key? */
  cipher_free(cctx);
  explicit_bzero(keyiv, sizeof(keyiv));
  explicit_bzero(&tmp, sizeof(tmp));
  freezero(enc, enclen);
  freezero(prekey, SSHKEY_SHIELD_PREKEY_LEN);
  sshkey_free(kswap);
  sshbuf_free(prvbuf);
  return r;
}

/* Check deterministic padding after private key */
static int
private2_check_padding(struct sshbuf *decrypted)
{
  u_char pad;
  size_t i;
  int r;

  i = 0;
  while (sshbuf_len(decrypted)) {
    if ((r = sshbuf_get_u8(decrypted, &pad)) != 0)
      goto out;
    if (pad != (++i & 0xff)) {
      r = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
  }
  /* success */
  r = 0;
 out:
  explicit_bzero(&pad, sizeof(pad));
  explicit_bzero(&i, sizeof(i));
  return r;
}

int
sshkey_unshield_private(struct sshkey *k)
{
  struct sshbuf *prvbuf = NULL;
  u_char *cp, keyiv[SSH_DIGEST_MAX_LENGTH];
  struct sshcipher_ctx *cctx = NULL;
  const struct sshcipher *cipher;
  struct sshkey *kswap = NULL, tmp;
  int r = SSH_ERR_INTERNAL_ERROR;

#ifdef DEBUG_PK
  fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
#endif
  if (!sshkey_is_shielded(k))
    return 0; /* nothing to do */

  if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
    r = SSH_ERR_INVALID_ARGUMENT;
    goto out;
  }
  if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
      ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
    r = SSH_ERR_INTERNAL_ERROR;
    goto out;
  }
  /* check size of shielded key blob */
  if (k->shielded_len < cipher_blocksize(cipher) ||
      (k->shielded_len % cipher_blocksize(cipher)) != 0) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* Calculate the ephemeral key from the prekey */
  if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
      k->shield_prekey, k->shield_prekey_len,
      keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
    goto out;
  if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
      keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0,
      CIPHER_DECRYPT, CIPHER_SERIAL)) != 0)
    goto out;
#ifdef DEBUG_PK
  fprintf(stderr, "%s: key+iv\n", __func__);
  sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
      stderr);
#endif

  /* Decrypt and parse the shielded private key using the ephemeral key */
  if ((prvbuf = sshbuf_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0)
    goto out;
  /* decrypt */
#ifdef DEBUG_PK
  fprintf(stderr, "%s: encrypted\n", __func__);
  sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr);
#endif
  if ((r = cipher_crypt(cctx, 0, cp, k->shielded_private, k->shielded_len,
      0, 0)) != 0)
    goto out;
#ifdef DEBUG_PK
  fprintf(stderr, "%s: serialised\n", __func__);
  sshbuf_dump(prvbuf, stderr);
#endif
  /* Parse private key */
  if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0)
    goto out;

  if ((r = private2_check_padding(prvbuf)) != 0)
    goto out;

  /* Swap the parsed key back into place */
  tmp = *kswap;
  *kswap = *k;
  *k = tmp;

  /* success */
  r = 0;

 out:
  cipher_free(cctx);
  explicit_bzero(keyiv, sizeof(keyiv));
  explicit_bzero(&tmp, sizeof(tmp));
  sshkey_free(kswap);
  sshbuf_free(prvbuf);
  return r;
}

static int
cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf)
{
  struct sshbuf *principals = NULL, *crit = NULL;
  struct sshbuf *exts = NULL, *ca = NULL;
  u_char *sig = NULL;
  size_t signed_len = 0, slen = 0, kidlen = 0;
  int ret = SSH_ERR_INTERNAL_ERROR;

  /* Copy the entire key blob for verification and later serialisation */
  if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0)
    return ret;

  /* Parse body of certificate up to signature */
  if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 ||
      (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 ||
      (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 ||
      (ret = sshbuf_froms(b, &principals)) != 0 ||
      (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 ||
      (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 ||
      (ret = sshbuf_froms(b, &crit)) != 0 ||
      (ret = sshbuf_froms(b, &exts)) != 0 ||
      (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 ||
      (ret = sshbuf_froms(b, &ca)) != 0) {
    /* XXX debug print error for ret */
    ret = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* Signature is left in the buffer so we can calculate this length */
  signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b);

  if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) {
    ret = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  if (key->cert->type != SSH2_CERT_TYPE_USER &&
      key->cert->type != SSH2_CERT_TYPE_HOST) {
    ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE;
    goto out;
  }

  /* Parse principals section */
  while (sshbuf_len(principals) > 0) {
    char *principal = NULL;
    char **oprincipals = NULL;

    if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) {
      ret = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
    if ((ret = sshbuf_get_cstring(principals, &principal,
        NULL)) != 0) {
      ret = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
    oprincipals = key->cert->principals;
    key->cert->principals = recallocarray(key->cert->principals,
        key->cert->nprincipals, key->cert->nprincipals + 1,
        sizeof(*key->cert->principals));
    if (key->cert->principals == NULL) {
      free(principal);
      key->cert->principals = oprincipals;
      ret = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    key->cert->principals[key->cert->nprincipals++] = principal;
  }

  /*
   * Stash a copies of the critical options and extensions sections
   * for later use.
   */
  if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 ||
      (exts != NULL &&
      (ret = sshbuf_putb(key->cert->extensions, exts)) != 0))
    goto out;

  /*
   * Validate critical options and extensions sections format.
   */
  while (sshbuf_len(crit) != 0) {
    if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 ||
        (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) {
      sshbuf_reset(key->cert->critical);
      ret = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
  }
  while (exts != NULL && sshbuf_len(exts) != 0) {
    if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 ||
        (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) {
      sshbuf_reset(key->cert->extensions);
      ret = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
  }

  /* Parse CA key and check signature */
  if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) {
    ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    goto out;
  }
  if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) {
    ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    goto out;
  }
  if ((ret = sshkey_verify(key->cert->signature_key, sig, slen,
      sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0)
    goto out;
  if ((ret = sshkey_get_sigtype(sig, slen,
      &key->cert->signature_type)) != 0)
    goto out;

  /* Success */
  ret = 0;
 out:
  sshbuf_free(ca);
  sshbuf_free(crit);
  sshbuf_free(exts);
  sshbuf_free(principals);
  free(sig);
  return ret;
}

int
sshkey_deserialize_sk(struct sshbuf *b, struct sshkey *key)
{
  /* Parse additional security-key application string */
  if (sshbuf_get_cstring(b, &key->sk_application, NULL) != 0)
    return SSH_ERR_INVALID_FORMAT;
  return 0;
}

static int
sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp,
    int allow_cert)
{
  int type, ret = SSH_ERR_INTERNAL_ERROR;
  char *ktype = NULL;
  struct sshkey *key = NULL;
  struct sshbuf *copy;
  const struct sshkey_impl *impl;

#ifdef DEBUG_PK /* XXX */
  sshbuf_dump(b, stderr);
#endif
  if (keyp != NULL)
    *keyp = NULL;
  if ((copy = sshbuf_fromb(b)) == NULL) {
    ret = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (sshbuf_get_cstring(b, &ktype, NULL) != 0) {
    ret = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  type = sshkey_type_from_name(ktype);
  if (!allow_cert && sshkey_type_is_cert(type)) {
    ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    goto out;
  }
  if ((impl = sshkey_impl_from_type(type)) == NULL) {
    ret = SSH_ERR_KEY_TYPE_UNKNOWN;
    goto out;
  }
  if ((key = sshkey_new(type)) == NULL) {
    ret = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (sshkey_type_is_cert(type)) {
    /* Skip nonce that precedes all certificates */
    if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
      ret = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
  }
  if ((ret = impl->funcs->deserialize_public(ktype, b, key)) != 0)
    goto out;

  /* Parse certificate potion */
  if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0)
    goto out;

  if (key != NULL && sshbuf_len(b) != 0) {
    ret = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  ret = 0;
  if (keyp != NULL) {
    *keyp = key;
    key = NULL;
  }
 out:
  sshbuf_free(copy);
  sshkey_free(key);
  free(ktype);
  return ret;
}

int
sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp)
{
  struct sshbuf *b;
  int r;

  if ((b = sshbuf_from(blob, blen)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  r = sshkey_from_blob_internal(b, keyp, 1);
  sshbuf_free(b);
  return r;
}

int
sshkey_fromb(struct sshbuf *b, struct sshkey **keyp)
{
  return sshkey_from_blob_internal(b, keyp, 1);
}

int
sshkey_froms(struct sshbuf *buf, struct sshkey **keyp)
{
  struct sshbuf *b;
  int r;

  if ((r = sshbuf_froms(buf, &b)) != 0)
    return r;
  r = sshkey_from_blob_internal(b, keyp, 1);
  sshbuf_free(b);
  return r;
}

int
sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep)
{
  int r;
  struct sshbuf *b = NULL;
  char *sigtype = NULL;

  if (sigtypep != NULL)
    *sigtypep = NULL;
  if ((b = sshbuf_from(sig, siglen)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0)
    goto out;
  /* success */
  if (sigtypep != NULL) {
    *sigtypep = sigtype;
    sigtype = NULL;
  }
  r = 0;
 out:
  free(sigtype);
  sshbuf_free(b);
  return r;
}

/*
 *
 * Checks whether a certificate's signature type is allowed.
 * Returns 0 (success) if the certificate signature type appears in the
 * "allowed" pattern-list, or the key is not a certificate to begin with.
 * Otherwise returns a ssherr.h code.
 */
int
sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed)
{
  if (key == NULL || allowed == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if (!sshkey_type_is_cert(key->type))
    return 0;
  if (key->cert == NULL || key->cert->signature_type == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1)
    return SSH_ERR_SIGN_ALG_UNSUPPORTED;
  return 0;
}

/*
 * Returns the expected signature algorithm for a given public key algorithm.
 */
const char *
sshkey_sigalg_by_name(const char *name)
{
  const struct sshkey_impl *impl;
  int i;

  for (i = 0; keyimpls[i] != NULL; i++) {
    impl = keyimpls[i];
    if (strcmp(impl->name, name) != 0)
      continue;
    if (impl->sigalg != NULL)
      return impl->sigalg;
    if (!impl->cert)
      return impl->name;
    return sshkey_ssh_name_from_type_nid(
        sshkey_type_plain(impl->type), impl->nid);
  }
  return NULL;
}

/*
 * Verifies that the signature algorithm appearing inside the signature blob
 * matches that which was requested.
 */
int
sshkey_check_sigtype(const u_char *sig, size_t siglen,
    const char *requested_alg)
{
  const char *expected_alg;
  char *sigtype = NULL;
  int r;

  if (requested_alg == NULL)
    return 0;
  if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0)
    return r;
  r = strcmp(expected_alg, sigtype) == 0;
  free(sigtype);
  return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED;
}

int
sshkey_sign(struct sshkey *key,
    u_char **sigp, size_t *lenp,
    const u_char *data, size_t datalen,
    const char *alg, const char *sk_provider, const char *sk_pin, u_int compat)
{
  int was_shielded = sshkey_is_shielded(key);
  int r2, r = SSH_ERR_INTERNAL_ERROR;
  const struct sshkey_impl *impl;

  if (sigp != NULL)
    *sigp = NULL;
  if (lenp != NULL)
    *lenp = 0;
  if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
    return SSH_ERR_INVALID_ARGUMENT;
  if ((impl = sshkey_impl_from_key(key)) == NULL)
    return SSH_ERR_KEY_TYPE_UNKNOWN;
  if ((r = sshkey_unshield_private(key)) != 0)
    return r;
  if (sshkey_is_sk(key)) {
    r = sshsk_sign(sk_provider, key, sigp, lenp, data,
        datalen, compat, sk_pin);
  } else {
    if (impl->funcs->sign == NULL)
      r = SSH_ERR_SIGN_ALG_UNSUPPORTED;
    else {
      r = impl->funcs->sign(key, sigp, lenp, data, datalen,
          alg, sk_provider, sk_pin, compat);
     }
  }
  if (was_shielded && (r2 = sshkey_shield_private(key)) != 0)
    return r2;
  return r;
}

/*
 * ssh_key_verify returns 0 for a correct signature  and < 0 on error.
 * If "alg" specified, then the signature must use that algorithm.
 */
int
sshkey_verify(const struct sshkey *key,
    const u_char *sig, size_t siglen,
    const u_char *data, size_t dlen, const char *alg, u_int compat,
    struct sshkey_sig_details **detailsp)
{
  const struct sshkey_impl *impl;

  if (detailsp != NULL)
    *detailsp = NULL;
  if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE)
    return SSH_ERR_INVALID_ARGUMENT;
  if ((impl = sshkey_impl_from_key(key)) == NULL)
    return SSH_ERR_KEY_TYPE_UNKNOWN;
  return impl->funcs->verify(key, sig, siglen, data, dlen,
      alg, compat, detailsp);
}

/* Convert a plain key to their _CERT equivalent */
int
sshkey_to_certified(struct sshkey *k)
{
  int newtype;

  if ((newtype = sshkey_type_certified(k->type)) == -1)
    return SSH_ERR_INVALID_ARGUMENT;
  if ((k->cert = cert_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  k->type = newtype;
  return 0;
}

/* Convert a certificate to its raw key equivalent */
int
sshkey_drop_cert(struct sshkey *k)
{
  if (!sshkey_type_is_cert(k->type))
    return SSH_ERR_KEY_TYPE_UNKNOWN;
  cert_free(k->cert);
  k->cert = NULL;
  k->type = sshkey_type_plain(k->type);
  return 0;
}

/* Sign a certified key, (re-)generating the signed certblob. */
int
sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg,
    const char *sk_provider, const char *sk_pin,
    sshkey_certify_signer *signer, void *signer_ctx)
{
  const struct sshkey_impl *impl;
  struct sshbuf *principals = NULL;
  u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32];
  size_t i, ca_len, sig_len;
  int ret = SSH_ERR_INTERNAL_ERROR;
  struct sshbuf *cert = NULL;
  char *sigtype = NULL;

  if (k == NULL || k->cert == NULL ||
      k->cert->certblob == NULL || ca == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if (!sshkey_is_cert(k))
    return SSH_ERR_KEY_TYPE_UNKNOWN;
  if (!sshkey_type_is_valid_ca(ca->type))
    return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
  if ((impl = sshkey_impl_from_key(k)) == NULL)
    return SSH_ERR_INTERNAL_ERROR;

  /*
   * If no alg specified as argument but a signature_type was set,
   * then prefer that. If both were specified, then they must match.
   */
  if (alg == NULL)
    alg = k->cert->signature_type;
  else if (k->cert->signature_type != NULL &&
      strcmp(alg, k->cert->signature_type) != 0)
    return SSH_ERR_INVALID_ARGUMENT;

  /*
   * If no signing algorithm or signature_type was specified and we're
   * using a RSA key, then default to a good signature algorithm.
   */
  if (alg == NULL && ca->type == KEY_RSA)
    alg = "rsa-sha2-512";

  if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0)
    return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;

  cert = k->cert->certblob; /* for readability */
  sshbuf_reset(cert);
  if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0)
    goto out;

  /* -v01 certs put nonce first */
  arc4random_buf(&nonce, sizeof(nonce));
  if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0)
    goto out;

  /* Public key next */
  if ((ret = impl->funcs->serialize_public(k, cert,
      SSHKEY_SERIALIZE_DEFAULT)) != 0)
    goto out;

  /* Then remaining cert fields */
  if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 ||
      (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 ||
      (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0)
    goto out;

  if ((principals = sshbuf_new()) == NULL) {
    ret = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  for (i = 0; i < k->cert->nprincipals; i++) {
    if ((ret = sshbuf_put_cstring(principals,
        k->cert->principals[i])) != 0)
      goto out;
  }
  if ((ret = sshbuf_put_stringb(cert, principals)) != 0 ||
      (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 ||
      (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 ||
      (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 ||
      (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 ||
      (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */
      (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0)
    goto out;

  /* Sign the whole mess */
  if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert),
      sshbuf_len(cert), alg, sk_provider, sk_pin, 0, signer_ctx)) != 0)
    goto out;
  /* Check and update signature_type against what was actually used */
  if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0)
    goto out;
  if (alg != NULL && strcmp(alg, sigtype) != 0) {
    ret = SSH_ERR_SIGN_ALG_UNSUPPORTED;
    goto out;
  }
  if (k->cert->signature_type == NULL) {
    k->cert->signature_type = sigtype;
    sigtype = NULL;
  }
  /* Append signature and we are done */
  if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0)
    goto out;
  ret = 0;
 out:
  if (ret != 0)
    sshbuf_reset(cert);
  free(sig_blob);
  free(ca_blob);
  free(sigtype);
  sshbuf_free(principals);
  return ret;
}

static int
default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp,
    const u_char *data, size_t datalen,
    const char *alg, const char *sk_provider, const char *sk_pin,
    u_int compat, void *ctx)
{
  if (ctx != NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  return sshkey_sign(key, sigp, lenp, data, datalen, alg,
      sk_provider, sk_pin, compat);
}

int
sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg,
    const char *sk_provider, const char *sk_pin)
{
  return sshkey_certify_custom(k, ca, alg, sk_provider, sk_pin,
      default_key_sign, NULL);
}

int
sshkey_cert_check_authority(const struct sshkey *k,
    int want_host, int require_principal, int wildcard_pattern,
    uint64_t verify_time, const char *name, const char **reason)
{
  u_int i, principal_matches;

  if (reason == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if (!sshkey_is_cert(k)) {
    *reason = "Key is not a certificate";
    return SSH_ERR_KEY_CERT_INVALID;
  }
  if (want_host) {
    if (k->cert->type != SSH2_CERT_TYPE_HOST) {
      *reason = "Certificate invalid: not a host certificate";
      return SSH_ERR_KEY_CERT_INVALID;
    }
  } else {
    if (k->cert->type != SSH2_CERT_TYPE_USER) {
      *reason = "Certificate invalid: not a user certificate";
      return SSH_ERR_KEY_CERT_INVALID;
    }
  }
  if (verify_time < k->cert->valid_after) {
    *reason = "Certificate invalid: not yet valid";
    return SSH_ERR_KEY_CERT_INVALID;
  }
  if (verify_time >= k->cert->valid_before) {
    *reason = "Certificate invalid: expired";
    return SSH_ERR_KEY_CERT_INVALID;
  }
  if (k->cert->nprincipals == 0) {
    if (require_principal) {
      *reason = "Certificate lacks principal list";
      return SSH_ERR_KEY_CERT_INVALID;
    }
  } else if (name != NULL) {
    principal_matches = 0;
    for (i = 0; i < k->cert->nprincipals; i++) {
      if (wildcard_pattern) {
        if (match_pattern(k->cert->principals[i],
            name)) {
          principal_matches = 1;
          break;
        }
      } else if (strcmp(name, k->cert->principals[i]) == 0) {
        principal_matches = 1;
        break;
      }
    }
    if (!principal_matches) {
      *reason = "Certificate invalid: name is not a listed "
          "principal";
      return SSH_ERR_KEY_CERT_INVALID;
    }
  }
  return 0;
}

int
sshkey_cert_check_authority_now(const struct sshkey *k,
    int want_host, int require_principal, int wildcard_pattern,
    const char *name, const char **reason)
{
  time_t now;

  if ((now = time(NULL)) < 0) {
    /* yikes - system clock before epoch! */
    *reason = "Certificate invalid: not yet valid";
    return SSH_ERR_KEY_CERT_INVALID;
  }
  return sshkey_cert_check_authority(k, want_host, require_principal,
      wildcard_pattern, (uint64_t)now, name, reason);
}

int
sshkey_cert_check_host(const struct sshkey *key, const char *host,
    int wildcard_principals, const char *ca_sign_algorithms,
    const char **reason)
{
  int r;

  if ((r = sshkey_cert_check_authority_now(key, 1, 0, wildcard_principals,
      host, reason)) != 0)
    return r;
  if (sshbuf_len(key->cert->critical) != 0) {
    *reason = "Certificate contains unsupported critical options";
    return SSH_ERR_KEY_CERT_INVALID;
  }
  if (ca_sign_algorithms != NULL &&
      (r = sshkey_check_cert_sigtype(key, ca_sign_algorithms)) != 0) {
    *reason = "Certificate signed with disallowed algorithm";
    return SSH_ERR_KEY_CERT_INVALID;
  }
  return 0;
}

size_t
sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l)
{
  char from[32], to[32], ret[128];

  *from = *to = '\0';
  if (cert->valid_after == 0 &&
      cert->valid_before == 0xffffffffffffffffULL)
    return strlcpy(s, "forever", l);

  if (cert->valid_after != 0)
    format_absolute_time(cert->valid_after, from, sizeof(from));
  if (cert->valid_before != 0xffffffffffffffffULL)
    format_absolute_time(cert->valid_before, to, sizeof(to));

  if (cert->valid_after == 0)
    snprintf(ret, sizeof(ret), "before %s", to);
  else if (cert->valid_before == 0xffffffffffffffffULL)
    snprintf(ret, sizeof(ret), "after %s", from);
  else
    snprintf(ret, sizeof(ret), "from %s to %s", from, to);

  return strlcpy(s, ret, l);
}

/* Common serialization for FIDO private keys */
int
sshkey_serialize_private_sk(const struct sshkey *key, struct sshbuf *b)
{
  int r;

  if ((r = sshbuf_put_cstring(b, key->sk_application)) != 0 ||
      (r = sshbuf_put_u8(b, key->sk_flags)) != 0 ||
      (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 ||
      (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0)
    return r;

  return 0;
}

int
sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
    enum sshkey_serialize_rep opts)
{
  int r = SSH_ERR_INTERNAL_ERROR;
  int was_shielded = sshkey_is_shielded(key);
  struct sshbuf *b = NULL;
  const struct sshkey_impl *impl;

  if ((impl = sshkey_impl_from_key(key)) == NULL)
    return SSH_ERR_INTERNAL_ERROR;
  if ((r = sshkey_unshield_private(key)) != 0)
    return r;
  if ((b = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0)
    goto out;
  if (sshkey_is_cert(key)) {
    if (key->cert == NULL ||
        sshbuf_len(key->cert->certblob) == 0) {
      r = SSH_ERR_INVALID_ARGUMENT;
      goto out;
    }
    if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0)
      goto out;
  }
  if ((r = impl->funcs->serialize_private(key, b, opts)) != 0)
    goto out;

  /*
   * success (but we still need to append the output to buf after
   * possibly re-shielding the private key)
   */
  r = 0;
 out:
  if (was_shielded)
    r = sshkey_shield_private(key);
  if (r == 0)
    r = sshbuf_putb(buf, b);
  sshbuf_free(b);

  return r;
}

int
sshkey_private_serialize(struct sshkey *key, struct sshbuf *b)
{
  return sshkey_private_serialize_opt(key, 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)
{
  const struct sshkey_impl *impl;
  char *tname = NULL;
  char *expect_sk_application = NULL;
  u_char *expect_ed25519_pk = NULL;
  struct sshkey *k = NULL;
  int type, r = SSH_ERR_INTERNAL_ERROR;

  if (kp != NULL)
    *kp = NULL;
  if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0)
    goto out;
  type = sshkey_type_from_name(tname);
  if (sshkey_type_is_cert(type)) {
    /*
     * Certificate key private keys begin with the certificate
     * itself. Make sure this matches the type of the enclosing
     * private key.
     */
    if ((r = sshkey_froms(buf, &k)) != 0)
      goto out;
    if (k->type != type) {
      r = SSH_ERR_KEY_CERT_MISMATCH;
      goto out;
    }
    /* For ECDSA keys, the group must match too */
    if (k->type == KEY_ECDSA &&
        k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) {
      r = SSH_ERR_KEY_CERT_MISMATCH;
      goto out;
    }
    /*
     * Several fields are redundant between certificate and
     * private key body, we require these to match.
     */
    expect_sk_application = k->sk_application;
    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;
    }
  }
  if ((impl = sshkey_impl_from_type(type)) == NULL) {
    r = SSH_ERR_INTERNAL_ERROR;
    goto out;
  }
  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 ||
      memcmp(expect_ed25519_pk, k->ed25519_pk, ED25519_PK_SZ) != 0))) {
    r = SSH_ERR_KEY_CERT_MISMATCH;
    goto out;
  }
  /* success */
  r = 0;
  if (kp != NULL) {
    *kp = k;
    k = NULL;
  }
 out:
  free(tname);
  sshkey_free(k);
  free(expect_sk_application);
  free(expect_ed25519_pk);
  return r;
}

#if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
int
sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
{
  EC_POINT *nq = NULL;
  BIGNUM *order = NULL, *x = NULL, *y = NULL, *tmp = NULL;
  int ret = SSH_ERR_KEY_INVALID_EC_VALUE;

  /*
   * NB. This assumes OpenSSL has already verified that the public
   * point lies on the curve. This is done by EC_POINT_oct2point()
   * implicitly calling EC_POINT_is_on_curve(). If this code is ever
   * reachable with public points not unmarshalled using
   * EC_POINT_oct2point then the caller will need to explicitly check.
   */

  /*
   * We shouldn't ever hit this case because bignum_get_ecpoint()
   * refuses to load GF2m points.
   */
  if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
      NID_X9_62_prime_field)
    goto out;

  /* Q != infinity */
  if (EC_POINT_is_at_infinity(group, public))
    goto out;

  if ((x = BN_new()) == NULL ||
      (y = BN_new()) == NULL ||
      (order = BN_new()) == NULL ||
      (tmp = BN_new()) == NULL) {
    ret = SSH_ERR_ALLOC_FAIL;
    goto out;
  }

  /* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */
  if (EC_GROUP_get_order(group, order, NULL) != 1 ||
      EC_POINT_get_affine_coordinates_GFp(group, public,
      x, y, NULL) != 1) {
    ret = SSH_ERR_LIBCRYPTO_ERROR;
    goto out;
  }
  if (BN_num_bits(x) <= BN_num_bits(order) / 2 ||
      BN_num_bits(y) <= BN_num_bits(order) / 2)
    goto out;

  /* nQ == infinity (n == order of subgroup) */
  if ((nq = EC_POINT_new(group)) == NULL) {
    ret = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) {
    ret = SSH_ERR_LIBCRYPTO_ERROR;
    goto out;
  }
  if (EC_POINT_is_at_infinity(group, nq) != 1)
    goto out;

  /* x < order - 1, y < order - 1 */
  if (!BN_sub(tmp, order, BN_value_one())) {
    ret = SSH_ERR_LIBCRYPTO_ERROR;
    goto out;
  }
  if (BN_cmp(x, tmp) >= 0 || BN_cmp(y, tmp) >= 0)
    goto out;
  ret = 0;
 out:
  BN_clear_free(x);
  BN_clear_free(y);
  BN_clear_free(order);
  BN_clear_free(tmp);
  EC_POINT_free(nq);
  return ret;
}

int
sshkey_ec_validate_private(const EC_KEY *key)
{
  BIGNUM *order = NULL, *tmp = NULL;
  int ret = SSH_ERR_KEY_INVALID_EC_VALUE;

  if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) {
    ret = SSH_ERR_ALLOC_FAIL;
    goto out;
  }

  /* log2(private) > log2(order)/2 */
  if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) {
    ret = SSH_ERR_LIBCRYPTO_ERROR;
    goto out;
  }
  if (BN_num_bits(EC_KEY_get0_private_key(key)) <=
      BN_num_bits(order) / 2)
    goto out;

  /* private < order - 1 */
  if (!BN_sub(tmp, order, BN_value_one())) {
    ret = SSH_ERR_LIBCRYPTO_ERROR;
    goto out;
  }
  if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0)
    goto out;
  ret = 0;
 out:
  BN_clear_free(order);
  BN_clear_free(tmp);
  return ret;
}

void
sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point)
{
  BIGNUM *x = NULL, *y = NULL;

  if (point == NULL) {
    fputs("point=(NULL)\n", stderr);
    return;
  }
  if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) {
    fprintf(stderr, "%s: BN_new failed\n", __func__);
    goto out;
  }
  if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
      NID_X9_62_prime_field) {
    fprintf(stderr, "%s: group is not a prime field\n", __func__);
    goto out;
  }
  if (EC_POINT_get_affine_coordinates_GFp(group, point,
      x, y, NULL) != 1) {
    fprintf(stderr, "%s: EC_POINT_get_affine_coordinates_GFp\n",
        __func__);
    goto out;
  }
  fputs("x=", stderr);
  BN_print_fp(stderr, x);
  fputs("\ny=", stderr);
  BN_print_fp(stderr, y);
  fputs("\n", stderr);
 out:
  BN_clear_free(x);
  BN_clear_free(y);
}

void
sshkey_dump_ec_key(const EC_KEY *key)
{
  const BIGNUM *exponent;

  sshkey_dump_ec_point(EC_KEY_get0_group(key),
      EC_KEY_get0_public_key(key));
  fputs("exponent=", stderr);
  if ((exponent = EC_KEY_get0_private_key(key)) == NULL)
    fputs("(NULL)", stderr);
  else
    BN_print_fp(stderr, EC_KEY_get0_private_key(key));
  fputs("\n", stderr);
}
#endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */

static int
sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob,
    const char *passphrase, const char *comment, const char *ciphername,
    int rounds)
{
  u_char *cp, *key = NULL, *pubkeyblob = NULL;
  u_char salt[SALT_LEN];
  size_t i, pubkeylen, keylen, ivlen, blocksize, authlen;
  u_int check;
  int r = SSH_ERR_INTERNAL_ERROR;
  struct sshcipher_ctx *ciphercontext = NULL;
  const struct sshcipher *cipher;
  const char *kdfname = KDFNAME;
  struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL;

  if (rounds <= 0)
    rounds = DEFAULT_ROUNDS;
  if (passphrase == NULL || !strlen(passphrase)) {
    ciphername = "none";
    kdfname = "none";
  } else if (ciphername == NULL)
    ciphername = DEFAULT_CIPHERNAME;
  /*
   * NOTE: Without OpenSSL, this string comparison is still safe, even
   * though it will never match because the multithreaded cipher is not
   * enabled.
   */
  else if (strcmp(ciphername, "chacha20-poly1305-mt@hpnssh.org") == 0)
    ciphername = "chacha20-poly1305@openssh.com";
  if ((cipher = cipher_by_name(ciphername)) == NULL) {
    r = SSH_ERR_INVALID_ARGUMENT;
    goto out;
  }

  if ((kdf = sshbuf_new()) == NULL ||
      (encoded = sshbuf_new()) == NULL ||
      (encrypted = sshbuf_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  blocksize = cipher_blocksize(cipher);
  keylen = cipher_keylen(cipher);
  ivlen = cipher_ivlen(cipher);
  authlen = cipher_authlen(cipher);
  if ((key = calloc(1, keylen + ivlen)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (strcmp(kdfname, "bcrypt") == 0) {
    arc4random_buf(salt, SALT_LEN);
    if (bcrypt_pbkdf(passphrase, strlen(passphrase),
        salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) {
      r = SSH_ERR_INVALID_ARGUMENT;
      goto out;
    }
    if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 ||
        (r = sshbuf_put_u32(kdf, rounds)) != 0)
      goto out;
  } else if (strcmp(kdfname, "none") != 0) {
    /* Unsupported KDF type */
    r = SSH_ERR_KEY_UNKNOWN_CIPHER;
    goto out;
  }
  if ((r = cipher_init(&ciphercontext, cipher, key, keylen, key + keylen,
      ivlen, 0, CIPHER_ENCRYPT, CIPHER_SERIAL)) != 0)
    goto out;

  if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 ||
      (r = sshbuf_put_cstring(encoded, ciphername)) != 0 ||
      (r = sshbuf_put_cstring(encoded, kdfname)) != 0 ||
      (r = sshbuf_put_stringb(encoded, kdf)) != 0 ||
      (r = sshbuf_put_u32(encoded, 1)) != 0 || /* number of keys */
      (r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 ||
      (r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0)
    goto out;

  /* set up the buffer that will be encrypted */

  /* Random check bytes */
  check = arc4random();
  if ((r = sshbuf_put_u32(encrypted, check)) != 0 ||
      (r = sshbuf_put_u32(encrypted, check)) != 0)
    goto out;

  /* append private key and comment*/
  if ((r = sshkey_private_serialize_opt(prv, encrypted,
      SSHKEY_SERIALIZE_FULL)) != 0 ||
      (r = sshbuf_put_cstring(encrypted, comment)) != 0)
    goto out;

  /* padding */
  i = 0;
  while (sshbuf_len(encrypted) % blocksize) {
    if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0)
      goto out;
  }

  /* length in destination buffer */
  if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0)
    goto out;

  /* encrypt */
  if ((r = sshbuf_reserve(encoded,
      sshbuf_len(encrypted) + authlen, &cp)) != 0)
    goto out;
  if ((r = cipher_crypt(ciphercontext, 0, cp, sshbuf_ptr(encrypted),
      sshbuf_len(encrypted), 0, authlen)) != 0)
    goto out;

  sshbuf_reset(blob);

  /* assemble uuencoded key */
  if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 ||
      (r = sshbuf_dtob64(encoded, blob, 1)) != 0 ||
      (r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0)
    goto out;

  /* success */
  r = 0;

 out:
  sshbuf_free(kdf);
  sshbuf_free(encoded);
  sshbuf_free(encrypted);
  cipher_free(ciphercontext);
  explicit_bzero(salt, sizeof(salt));
  if (key != NULL)
    freezero(key, keylen + ivlen);
  if (pubkeyblob != NULL)
    freezero(pubkeyblob, pubkeylen);
  return r;
}

static int
private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp)
{
  const u_char *cp;
  size_t encoded_len;
  int r;
  u_char last;
  struct sshbuf *encoded = NULL, *decoded = NULL;

  if (blob == NULL || decodedp == NULL)
    return SSH_ERR_INVALID_ARGUMENT;

  *decodedp = NULL;

  if ((encoded = sshbuf_new()) == NULL ||
      (decoded = sshbuf_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }

  /* check preamble */
  cp = sshbuf_ptr(blob);
  encoded_len = sshbuf_len(blob);
  if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) ||
      memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  cp += MARK_BEGIN_LEN;
  encoded_len -= MARK_BEGIN_LEN;

  /* Look for end marker, removing whitespace as we go */
  while (encoded_len > 0) {
    if (*cp != '\n' && *cp != '\r') {
      if ((r = sshbuf_put_u8(encoded, *cp)) != 0)
        goto out;
    }
    last = *cp;
    encoded_len--;
    cp++;
    if (last == '\n') {
      if (encoded_len >= MARK_END_LEN &&
          memcmp(cp, MARK_END, MARK_END_LEN) == 0) {
        /* \0 terminate */
        if ((r = sshbuf_put_u8(encoded, 0)) != 0)
          goto out;
        break;
      }
    }
  }
  if (encoded_len == 0) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* decode base64 */
  if ((r = sshbuf_b64tod(decoded, (char *)sshbuf_ptr(encoded))) != 0)
    goto out;

  /* check magic */
  if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) ||
      memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  /* success */
  *decodedp = decoded;
  decoded = NULL;
  r = 0;
 out:
  sshbuf_free(encoded);
  sshbuf_free(decoded);
  return r;
}

static int
private2_decrypt(struct sshbuf *decoded, const char *passphrase,
    struct sshbuf **decryptedp, struct sshkey **pubkeyp)
{
  char *ciphername = NULL, *kdfname = NULL;
  const struct sshcipher *cipher = NULL;
  int r = SSH_ERR_INTERNAL_ERROR;
  size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0;
  struct sshbuf *kdf = NULL, *decrypted = NULL;
  struct sshcipher_ctx *ciphercontext = NULL;
  struct sshkey *pubkey = NULL;
  u_char *key = NULL, *salt = NULL, *dp;
  u_int blocksize, rounds, nkeys, encrypted_len, check1, check2;

  if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL)
    return SSH_ERR_INVALID_ARGUMENT;

  *decryptedp = NULL;
  *pubkeyp = NULL;

  if ((decrypted = sshbuf_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }

  /* parse public portion of key */
  if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 ||
      (r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 ||
      (r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 ||
      (r = sshbuf_froms(decoded, &kdf)) != 0 ||
      (r = sshbuf_get_u32(decoded, &nkeys)) != 0)
    goto out;

  if (nkeys != 1) {
    /* XXX only one key supported at present */
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  if ((r = sshkey_froms(decoded, &pubkey)) != 0 ||
      (r = sshbuf_get_u32(decoded, &encrypted_len)) != 0)
    goto out;

  if (strcmp(ciphername, "chacha20-poly1305-mt@hpnssh.org") == 0)
    strcpy(ciphername, "chacha20-poly1305@openssh.com");
  if ((cipher = cipher_by_name(ciphername)) == NULL) {
    r = SSH_ERR_KEY_UNKNOWN_CIPHER;
    goto out;
  }
  if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) {
    r = SSH_ERR_KEY_UNKNOWN_CIPHER;
    goto out;
  }
  if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  if ((passphrase == NULL || strlen(passphrase) == 0) &&
      strcmp(kdfname, "none") != 0) {
    /* passphrase required */
    r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    goto out;
  }

  /* check size of encrypted key blob */
  blocksize = cipher_blocksize(cipher);
  if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* setup key */
  keylen = cipher_keylen(cipher);
  ivlen = cipher_ivlen(cipher);
  authlen = cipher_authlen(cipher);
  if ((key = calloc(1, keylen + ivlen)) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (strcmp(kdfname, "bcrypt") == 0) {
    if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 ||
        (r = sshbuf_get_u32(kdf, &rounds)) != 0)
      goto out;
    if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen,
        key, keylen + ivlen, rounds) < 0) {
      r = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
  }

  /* check that an appropriate amount of auth data is present */
  if (sshbuf_len(decoded) < authlen ||
      sshbuf_len(decoded) - authlen < encrypted_len) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* decrypt private portion of key */
  if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 ||
      (r = cipher_init(&ciphercontext, cipher, key, keylen, key + keylen,
      ivlen, 0, CIPHER_DECRYPT, CIPHER_SERIAL)) != 0)
    goto out;
  if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded),
      encrypted_len, 0, authlen)) != 0) {
    /* an integrity error here indicates an incorrect passphrase */
    if (r == SSH_ERR_MAC_INVALID)
      r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    goto out;
  }
  if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0)
    goto out;
  /* there should be no trailing data */
  if (sshbuf_len(decoded) != 0) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* check check bytes */
  if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 ||
      (r = sshbuf_get_u32(decrypted, &check2)) != 0)
    goto out;
  if (check1 != check2) {
    r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    goto out;
  }
  /* success */
  *decryptedp = decrypted;
  decrypted = NULL;
  *pubkeyp = pubkey;
  pubkey = NULL;
  r = 0;
 out:
  cipher_free(ciphercontext);
  free(ciphername);
  free(kdfname);
  sshkey_free(pubkey);
  if (salt != NULL) {
    explicit_bzero(salt, slen);
    free(salt);
  }
  if (key != NULL) {
    explicit_bzero(key, keylen + ivlen);
    free(key);
  }
  sshbuf_free(kdf);
  sshbuf_free(decrypted);
  return r;
}

static int
sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase,
    struct sshkey **keyp, char **commentp)
{
  char *comment = NULL;
  int r = SSH_ERR_INTERNAL_ERROR;
  struct sshbuf *decoded = NULL, *decrypted = NULL;
  struct sshkey *k = NULL, *pubkey = NULL;

  if (keyp != NULL)
    *keyp = NULL;
  if (commentp != NULL)
    *commentp = NULL;

  /* Undo base64 encoding and decrypt the private section */
  if ((r = private2_uudecode(blob, &decoded)) != 0 ||
      (r = private2_decrypt(decoded, passphrase,
      &decrypted, &pubkey)) != 0)
    goto out;

  if (type != KEY_UNSPEC &&
      sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) {
    r = SSH_ERR_KEY_TYPE_MISMATCH;
    goto out;
  }

  /* Load the private key and comment */
  if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 ||
      (r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0)
    goto out;

  /* Check deterministic padding after private section */
  if ((r = private2_check_padding(decrypted)) != 0)
    goto out;

  /* Check that the public key in the envelope matches the private key */
  if (!sshkey_equal(pubkey, k)) {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* success */
  r = 0;
  if (keyp != NULL) {
    *keyp = k;
    k = NULL;
  }
  if (commentp != NULL) {
    *commentp = comment;
    comment = NULL;
  }
 out:
  free(comment);
  sshbuf_free(decoded);
  sshbuf_free(decrypted);
  sshkey_free(k);
  sshkey_free(pubkey);
  return r;
}

static int
sshkey_parse_private2_pubkey(struct sshbuf *blob, int type,
    struct sshkey **keyp)
{
  int r = SSH_ERR_INTERNAL_ERROR;
  struct sshbuf *decoded = NULL;
  struct sshkey *pubkey = NULL;
  u_int nkeys = 0;

  if (keyp != NULL)
    *keyp = NULL;

  if ((r = private2_uudecode(blob, &decoded)) != 0)
    goto out;
  /* parse public key from unencrypted envelope */
  if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 ||
      (r = sshbuf_skip_string(decoded)) != 0 || /* cipher */
      (r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */
      (r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */
      (r = sshbuf_get_u32(decoded, &nkeys)) != 0)
    goto out;

  if (nkeys != 1) {
    /* XXX only one key supported at present */
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }

  /* Parse the public key */
  if ((r = sshkey_froms(decoded, &pubkey)) != 0)
    goto out;

  if (type != KEY_UNSPEC &&
      sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) {
    r = SSH_ERR_KEY_TYPE_MISMATCH;
    goto out;
  }

  /* success */
  r = 0;
  if (keyp != NULL) {
    *keyp = pubkey;
    pubkey = NULL;
  }
 out:
  sshbuf_free(decoded);
  sshkey_free(pubkey);
  return r;
}

#ifdef WITH_OPENSSL
/* convert SSH v2 key to PEM or PKCS#8 format */
static int
sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf,
    int format, const char *_passphrase, const char *comment)
{
  int was_shielded = sshkey_is_shielded(key);
  int success, r;
  int blen, len = strlen(_passphrase);
  u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
  const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
  char *bptr;
  BIO *bio = NULL;
  struct sshbuf *blob;
  EVP_PKEY *pkey = NULL;

  if (len > 0 && len <= 4)
    return SSH_ERR_PASSPHRASE_TOO_SHORT;
  if ((blob = sshbuf_new()) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  if ((bio = BIO_new(BIO_s_mem())) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if (format == SSHKEY_PRIVATE_PKCS8 && (pkey = EVP_PKEY_new()) == NULL) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }
  if ((r = sshkey_unshield_private(key)) != 0)
    goto out;

  switch (key->type) {
#ifdef WITH_DSA
  case KEY_DSA:
    if (format == SSHKEY_PRIVATE_PEM) {
      success = PEM_write_bio_DSAPrivateKey(bio, key->dsa,
          cipher, passphrase, len, NULL, NULL);
    } else {
      success = EVP_PKEY_set1_DSA(pkey, key->dsa);
    }
    break;
#endif
#ifdef OPENSSL_HAS_ECC
  case KEY_ECDSA:
    if (format == SSHKEY_PRIVATE_PEM) {
      success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa,
          cipher, passphrase, len, NULL, NULL);
    } else {
      success = EVP_PKEY_set1_EC_KEY(pkey, key->ecdsa);
    }
    break;
#endif
  case KEY_RSA:
    if (format == SSHKEY_PRIVATE_PEM) {
      success = PEM_write_bio_RSAPrivateKey(bio, key->rsa,
          cipher, passphrase, len, NULL, NULL);
    } else {
      success = EVP_PKEY_set1_RSA(pkey, key->rsa);
    }
    break;
  default:
    success = 0;
    break;
  }
  if (success == 0) {
    r = SSH_ERR_LIBCRYPTO_ERROR;
    goto out;
  }
  if (format == SSHKEY_PRIVATE_PKCS8) {
    if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher,
        passphrase, len, NULL, NULL)) == 0) {
      r = SSH_ERR_LIBCRYPTO_ERROR;
      goto out;
    }
  }
  if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) {
    r = SSH_ERR_INTERNAL_ERROR;
    goto out;
  }
  if ((r = sshbuf_put(blob, bptr, blen)) != 0)
    goto out;
  r = 0;
 out:
  if (was_shielded)
    r = sshkey_shield_private(key);
  if (r == 0)
    r = sshbuf_putb(buf, blob);

  EVP_PKEY_free(pkey);
  sshbuf_free(blob);
  BIO_free(bio);
  return r;
}
#endif /* WITH_OPENSSL */

/* Serialise "key" to buffer "blob" */
int
sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
    const char *passphrase, const char *comment,
    int format, const char *openssh_format_cipher, int openssh_format_rounds)
{
  switch (key->type) {
#ifdef WITH_OPENSSL
  case KEY_DSA:
  case KEY_ECDSA:
  case KEY_RSA:
    break; /* see below */
#endif /* WITH_OPENSSL */
  case KEY_ED25519:
  case KEY_ED25519_SK:
#ifdef WITH_XMSS
  case KEY_XMSS:
#endif /* WITH_XMSS */
#ifdef WITH_OPENSSL
  case KEY_ECDSA_SK:
#endif /* WITH_OPENSSL */
    return sshkey_private_to_blob2(key, blob, passphrase,
        comment, openssh_format_cipher, openssh_format_rounds);
  default:
    return SSH_ERR_KEY_TYPE_UNKNOWN;
  }

#ifdef WITH_OPENSSL
  switch (format) {
  case SSHKEY_PRIVATE_OPENSSH:
    return sshkey_private_to_blob2(key, blob, passphrase,
        comment, openssh_format_cipher, openssh_format_rounds);
  case SSHKEY_PRIVATE_PEM:
  case SSHKEY_PRIVATE_PKCS8:
    return sshkey_private_to_blob_pem_pkcs8(key, blob,
        format, passphrase, comment);
  default:
    return SSH_ERR_INVALID_ARGUMENT;
  }
#endif /* WITH_OPENSSL */
}

#ifdef WITH_OPENSSL
static int
translate_libcrypto_error(unsigned long pem_err)
{
  int pem_reason = ERR_GET_REASON(pem_err);

  switch (ERR_GET_LIB(pem_err)) {
  case ERR_LIB_PEM:
    switch (pem_reason) {
    case PEM_R_BAD_PASSWORD_READ:
#ifdef PEM_R_PROBLEMS_GETTING_PASSWORD
    case PEM_R_PROBLEMS_GETTING_PASSWORD:
#endif
#ifdef PEM_R_BAD_DECRYPT
    case PEM_R_BAD_DECRYPT:
#endif
      return SSH_ERR_KEY_WRONG_PASSPHRASE;
    default:
      return SSH_ERR_INVALID_FORMAT;
    }
  case ERR_LIB_EVP:
    switch (pem_reason) {
#ifdef EVP_R_BAD_DECRYPT
    case EVP_R_BAD_DECRYPT:
      return SSH_ERR_KEY_WRONG_PASSPHRASE;
#endif
#ifdef EVP_R_BN_DECODE_ERROR
    case EVP_R_BN_DECODE_ERROR:
#endif
    case EVP_R_DECODE_ERROR:
#ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR
    case EVP_R_PRIVATE_KEY_DECODE_ERROR:
#endif
      return SSH_ERR_INVALID_FORMAT;
    default:
      return SSH_ERR_LIBCRYPTO_ERROR;
    }
  case ERR_LIB_ASN1:
    return SSH_ERR_INVALID_FORMAT;
  }
  return SSH_ERR_LIBCRYPTO_ERROR;
}

static void
clear_libcrypto_errors(void)
{
  while (ERR_get_error() != 0)
    ;
}

/*
 * Translate OpenSSL error codes to determine whether
 * passphrase is required/incorrect.
 */
static int
convert_libcrypto_error(void)
{
  /*
   * Some password errors are reported at the beginning
   * of the error queue.
   */
  if (translate_libcrypto_error(ERR_peek_error()) ==
      SSH_ERR_KEY_WRONG_PASSPHRASE)
    return SSH_ERR_KEY_WRONG_PASSPHRASE;
  return translate_libcrypto_error(ERR_peek_last_error());
}

static int
pem_passphrase_cb(char *buf, int size, int rwflag, void *u)
{
  char *p = (char *)u;
  size_t len;

  if (p == NULL || (len = strlen(p)) == 0)
    return -1;
  if (size < 0 || len > (size_t)size)
    return -1;
  memcpy(buf, p, len);
  return (int)len;
}

static int
sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type,
    const char *passphrase, struct sshkey **keyp)
{
  EVP_PKEY *pk = NULL;
  struct sshkey *prv = NULL;
  BIO *bio = NULL;
  int r;

  if (keyp != NULL)
    *keyp = NULL;

  if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX)
    return SSH_ERR_ALLOC_FAIL;
  if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) !=
      (int)sshbuf_len(blob)) {
    r = SSH_ERR_ALLOC_FAIL;
    goto out;
  }

  clear_libcrypto_errors();
  if ((pk = PEM_read_bio_PrivateKey(bio, NULL, pem_passphrase_cb,
      (char *)passphrase)) == NULL) {
    /*
     * libcrypto may return various ASN.1 errors when attempting
     * to parse a key with an incorrect passphrase.
     * Treat all format errors as "incorrect passphrase" if a
     * passphrase was supplied.
     */
    if (passphrase != NULL && *passphrase != '\0')
      r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    else
      r = convert_libcrypto_error();
    goto out;
  }
  if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA &&
      (type == KEY_UNSPEC || type == KEY_RSA)) {
    if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
      r = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    prv->rsa = EVP_PKEY_get1_RSA(pk);
    prv->type = KEY_RSA;
#ifdef DEBUG_PK
    RSA_print_fp(stderr, prv->rsa, 8);
#endif
    if (RSA_blinding_on(prv->rsa, NULL) != 1) {
      r = SSH_ERR_LIBCRYPTO_ERROR;
      goto out;
    }
    if ((r = sshkey_check_rsa_length(prv, 0)) != 0)
      goto out;
#ifdef WITH_DSA
  } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_DSA &&
      (type == KEY_UNSPEC || type == KEY_DSA)) {
    if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
      r = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    prv->dsa = EVP_PKEY_get1_DSA(pk);
    prv->type = KEY_DSA;
#ifdef DEBUG_PK
    DSA_print_fp(stderr, prv->dsa, 8);
#endif
#endif
#ifdef OPENSSL_HAS_ECC
  } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC &&
      (type == KEY_UNSPEC || type == KEY_ECDSA)) {
    if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
      r = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
    prv->type = KEY_ECDSA;
    prv->ecdsa_nid = sshkey_ecdsa_key_to_nid(prv->ecdsa);
    if (prv->ecdsa_nid == -1 ||
        sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
        sshkey_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
        EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
        sshkey_ec_validate_private(prv->ecdsa) != 0) {
      r = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
# ifdef DEBUG_PK
    if (prv != NULL && prv->ecdsa != NULL)
      sshkey_dump_ec_key(prv->ecdsa);
# endif
#endif /* OPENSSL_HAS_ECC */
#ifdef OPENSSL_HAS_ED25519
  } else if (EVP_PKEY_base_id(pk) == EVP_PKEY_ED25519 &&
      (type == KEY_UNSPEC || type == KEY_ED25519)) {
    size_t len;

    if ((prv = sshkey_new(KEY_UNSPEC)) == NULL ||
        (prv->ed25519_sk = calloc(1, ED25519_SK_SZ)) == NULL ||
        (prv->ed25519_pk = calloc(1, ED25519_PK_SZ)) == NULL) {
      r = SSH_ERR_ALLOC_FAIL;
      goto out;
    }
    prv->type = KEY_ED25519;
    len = ED25519_PK_SZ;
    if (!EVP_PKEY_get_raw_public_key(pk, prv->ed25519_pk, &len)) {
      r = SSH_ERR_LIBCRYPTO_ERROR;
      goto out;
    }
    if (len != ED25519_PK_SZ) {
      r = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
    len = ED25519_SK_SZ - ED25519_PK_SZ;
    if (!EVP_PKEY_get_raw_private_key(pk, prv->ed25519_sk, &len)) {
      r = SSH_ERR_LIBCRYPTO_ERROR;
      goto out;
    }
    if (len != ED25519_SK_SZ - ED25519_PK_SZ) {
      r = SSH_ERR_INVALID_FORMAT;
      goto out;
    }
    /* Append the public key to our private key */
    memcpy(prv->ed25519_sk + (ED25519_SK_SZ - ED25519_PK_SZ),
        prv->ed25519_pk, ED25519_PK_SZ);
# ifdef DEBUG_PK
    sshbuf_dump_data(prv->ed25519_sk, ED25519_SK_SZ, stderr);
# endif
#endif /* OPENSSL_HAS_ED25519 */
  } else {
    r = SSH_ERR_INVALID_FORMAT;
    goto out;
  }
  r = 0;
  if (keyp != NULL) {
    *keyp = prv;
    prv = NULL;
  }
 out:
  BIO_free(bio);
  EVP_PKEY_free(pk);
  sshkey_free(prv);
  return r;
}
#endif /* WITH_OPENSSL */

int
sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
    const char *passphrase, struct sshkey **keyp, char **commentp)
{
  int r = SSH_ERR_INTERNAL_ERROR;

  if (keyp != NULL)
    *keyp = NULL;
  if (commentp != NULL)
    *commentp = NULL;

  switch (type) {
  case KEY_XMSS:
    /* No fallback for new-format-only keys */
    return sshkey_parse_private2(blob, type, passphrase,
        keyp, commentp);
  default:
    r = sshkey_parse_private2(blob, type, passphrase, keyp,
        commentp);
    /* Only fallback to PEM parser if a format error occurred. */
    if (r != SSH_ERR_INVALID_FORMAT)
      return r;
#ifdef WITH_OPENSSL
    return sshkey_parse_private_pem_fileblob(blob, type,
        passphrase, keyp);
#else
    return SSH_ERR_INVALID_FORMAT;
#endif /* WITH_OPENSSL */
  }
}

int
sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase,
    struct sshkey **keyp, char **commentp)
{
  if (keyp != NULL)
    *keyp = NULL;
  if (commentp != NULL)
    *commentp = NULL;

  return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC,
      passphrase, keyp, commentp);
}

void
sshkey_sig_details_free(struct sshkey_sig_details *details)
{
  freezero(details, sizeof(*details));
}

int
sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type,
    struct sshkey **pubkeyp)
{
  int r = SSH_ERR_INTERNAL_ERROR;

  if (pubkeyp != NULL)
    *pubkeyp = NULL;
  /* only new-format private keys bundle a public key inside */
  if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0)
    return r;
  return 0;
}

#ifdef WITH_XMSS
/*
 * serialize the key with the current state and forward the state
 * maxsign times.
 */
int
sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b,
    u_int32_t maxsign, int printerror)
{
  int r, rupdate;

  if (maxsign == 0 ||
      sshkey_type_plain(k->type) != KEY_XMSS)
    return sshkey_private_serialize_opt(k, b,
        SSHKEY_SERIALIZE_DEFAULT);
  if ((r = sshkey_xmss_get_state(k, printerror)) != 0 ||
      (r = sshkey_private_serialize_opt(k, b,
      SSHKEY_SERIALIZE_STATE)) != 0 ||
      (r = sshkey_xmss_forward_state(k, maxsign)) != 0)
    goto out;
  r = 0;
out:
  if ((rupdate = sshkey_xmss_update_state(k, printerror)) != 0) {
    if (r == 0)
      r = rupdate;
  }
  return r;
}

u_int32_t
sshkey_signatures_left(const struct sshkey *k)
{
  if (sshkey_type_plain(k->type) == KEY_XMSS)
    return sshkey_xmss_signatures_left(k);
  return 0;
}

int
sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
{
  if (sshkey_type_plain(k->type) != KEY_XMSS)
    return SSH_ERR_INVALID_ARGUMENT;
  return sshkey_xmss_enable_maxsign(k, maxsign);
}

int
sshkey_set_filename(struct sshkey *k, const char *filename)
{
  if (k == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if (sshkey_type_plain(k->type) != KEY_XMSS)
    return 0;
  if (filename == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  if ((k->xmss_filename = strdup(filename)) == NULL)
    return SSH_ERR_ALLOC_FAIL;
  return 0;
}
#else
int
sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b,
    u_int32_t maxsign, int printerror)
{
  return sshkey_private_serialize_opt(k, b, SSHKEY_SERIALIZE_DEFAULT);
}

u_int32_t
sshkey_signatures_left(const struct sshkey *k)
{
  return 0;
}

int
sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
{
  return SSH_ERR_INVALID_ARGUMENT;
}

int
sshkey_set_filename(struct sshkey *k, const char *filename)
{
  if (k == NULL)
    return SSH_ERR_INVALID_ARGUMENT;
  return 0;
}
#endif /* WITH_XMSS */

Coverage Report

Created: 2024-06-18 06:23