/src/openssh/ssh-pkcs11.c

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/* $OpenBSD: ssh-pkcs11.c,v 1.64 2024/09/20 02:00:46 jsg Exp $ */
/*
 * Copyright (c) 2010 Markus Friedl.  All rights reserved.
 * Copyright (c) 2014 Pedro Martelletto. All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "includes.h"

#ifdef ENABLE_PKCS11

#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif

#include <sys/types.h>
#include <stdarg.h>
#include <stdio.h>

#include <ctype.h>
#include <string.h>
#include <dlfcn.h>

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

#include <openssl/ecdsa.h>
#include <openssl/x509.h>
#include <openssl/err.h>

#define CRYPTOKI_COMPAT
#include "pkcs11.h"

#include "log.h"
#include "misc.h"
#include "sshkey.h"
#include "ssh-pkcs11.h"
#include "digest.h"
#include "xmalloc.h"

struct pkcs11_slotinfo {
  CK_TOKEN_INFO   token;
  CK_SESSION_HANDLE session;
  int     logged_in;
};

struct pkcs11_provider {
  char      *name;
  void      *handle;
  CK_FUNCTION_LIST  *function_list;
  CK_INFO     info;
  CK_ULONG    nslots;
  CK_SLOT_ID    *slotlist;
  struct pkcs11_slotinfo  *slotinfo;
  int     valid;
  int     refcount;
  TAILQ_ENTRY(pkcs11_provider) next;
};

TAILQ_HEAD(, pkcs11_provider) pkcs11_providers;

struct pkcs11_key {
  struct pkcs11_provider  *provider;
  CK_ULONG    slotidx;
  char      *keyid;
  int     keyid_len;
};

int pkcs11_interactive = 0;

#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
static void
ossl_error(const char *msg)
{
  unsigned long    e;

  error_f("%s", msg);
  while ((e = ERR_get_error()) != 0)
    error_f("libcrypto error: %s", ERR_error_string(e, NULL));
}
#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */

int
pkcs11_init(int interactive)
{
  pkcs11_interactive = interactive;
  TAILQ_INIT(&pkcs11_providers);
  return (0);
}

/*
 * finalize a provider shared library, it's no longer usable.
 * however, there might still be keys referencing this provider,
 * so the actual freeing of memory is handled by pkcs11_provider_unref().
 * this is called when a provider gets unregistered.
 */
static void
pkcs11_provider_finalize(struct pkcs11_provider *p)
{
  CK_RV rv;
  CK_ULONG i;

  debug_f("provider \"%s\" refcount %d valid %d",
      p->name, p->refcount, p->valid);
  if (!p->valid)
    return;
  for (i = 0; i < p->nslots; i++) {
    if (p->slotinfo[i].session &&
        (rv = p->function_list->C_CloseSession(
        p->slotinfo[i].session)) != CKR_OK)
      error("C_CloseSession failed: %lu", rv);
  }
  if ((rv = p->function_list->C_Finalize(NULL)) != CKR_OK)
    error("C_Finalize failed: %lu", rv);
  p->valid = 0;
  p->function_list = NULL;
  dlclose(p->handle);
}

/*
 * remove a reference to the provider.
 * called when a key gets destroyed or when the provider is unregistered.
 */
static void
pkcs11_provider_unref(struct pkcs11_provider *p)
{
  debug_f("provider \"%s\" refcount %d", p->name, p->refcount);
  if (--p->refcount <= 0) {
    if (p->valid)
      error_f("provider \"%s\" still valid", p->name);
    free(p->name);
    free(p->slotlist);
    free(p->slotinfo);
    free(p);
  }
}

/* unregister all providers, keys might still point to the providers */
void
pkcs11_terminate(void)
{
  struct pkcs11_provider *p;

  while ((p = TAILQ_FIRST(&pkcs11_providers)) != NULL) {
    TAILQ_REMOVE(&pkcs11_providers, p, next);
    pkcs11_provider_finalize(p);
    pkcs11_provider_unref(p);
  }
}

/* lookup provider by name */
static struct pkcs11_provider *
pkcs11_provider_lookup(char *provider_id)
{
  struct pkcs11_provider *p;

  TAILQ_FOREACH(p, &pkcs11_providers, next) {
    debug("check provider \"%s\"", p->name);
    if (!strcmp(provider_id, p->name))
      return (p);
  }
  return (NULL);
}

/* unregister provider by name */
int
pkcs11_del_provider(char *provider_id)
{
  struct pkcs11_provider *p;

  if ((p = pkcs11_provider_lookup(provider_id)) != NULL) {
    TAILQ_REMOVE(&pkcs11_providers, p, next);
    pkcs11_provider_finalize(p);
    pkcs11_provider_unref(p);
    return (0);
  }
  return (-1);
}

static RSA_METHOD *rsa_method;
static int rsa_idx = 0;
#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
static EC_KEY_METHOD *ec_key_method;
static int ec_key_idx = 0;
#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */

/* release a wrapped object */
static void
pkcs11_k11_free(void *parent, void *ptr, CRYPTO_EX_DATA *ad, int idx,
    long argl, void *argp)
{
  struct pkcs11_key *k11 = ptr;

  debug_f("parent %p ptr %p idx %d", parent, ptr, idx);
  if (k11 == NULL)
    return;
  if (k11->provider)
    pkcs11_provider_unref(k11->provider);
  free(k11->keyid);
  free(k11);
}

/* find a single 'obj' for given attributes */
static int
pkcs11_find(struct pkcs11_provider *p, CK_ULONG slotidx, CK_ATTRIBUTE *attr,
    CK_ULONG nattr, CK_OBJECT_HANDLE *obj)
{
  CK_FUNCTION_LIST  *f;
  CK_SESSION_HANDLE session;
  CK_ULONG    nfound = 0;
  CK_RV     rv;
  int     ret = -1;

  f = p->function_list;
  session = p->slotinfo[slotidx].session;
  if ((rv = f->C_FindObjectsInit(session, attr, nattr)) != CKR_OK) {
    error("C_FindObjectsInit failed (nattr %lu): %lu", nattr, rv);
    return (-1);
  }
  if ((rv = f->C_FindObjects(session, obj, 1, &nfound)) != CKR_OK ||
      nfound != 1) {
    debug("C_FindObjects failed (nfound %lu nattr %lu): %lu",
        nfound, nattr, rv);
  } else
    ret = 0;
  if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK)
    error("C_FindObjectsFinal failed: %lu", rv);
  return (ret);
}

static int
pkcs11_login_slot(struct pkcs11_provider *provider, struct pkcs11_slotinfo *si,
    CK_USER_TYPE type)
{
  char      *pin = NULL, prompt[1024];
  CK_RV      rv;

  if (provider == NULL || si == NULL || !provider->valid) {
    error("no pkcs11 (valid) provider found");
    return (-1);
  }

  if (!pkcs11_interactive) {
    error("need pin entry%s",
        (si->token.flags & CKF_PROTECTED_AUTHENTICATION_PATH) ?
        " on reader keypad" : "");
    return (-1);
  }
  if (si->token.flags & CKF_PROTECTED_AUTHENTICATION_PATH)
    verbose("Deferring PIN entry to reader keypad.");
  else {
    snprintf(prompt, sizeof(prompt), "Enter PIN for '%s': ",
        si->token.label);
    if ((pin = read_passphrase(prompt, RP_ALLOW_EOF)) == NULL) {
      debug_f("no pin specified");
      return (-1);  /* bail out */
    }
  }
  rv = provider->function_list->C_Login(si->session, type, (u_char *)pin,
      (pin != NULL) ? strlen(pin) : 0);
  if (pin != NULL)
    freezero(pin, strlen(pin));

  switch (rv) {
  case CKR_OK:
  case CKR_USER_ALREADY_LOGGED_IN:
    /* success */
    break;
  case CKR_PIN_LEN_RANGE:
    error("PKCS#11 login failed: PIN length out of range");
    return -1;
  case CKR_PIN_INCORRECT:
    error("PKCS#11 login failed: PIN incorrect");
    return -1;
  case CKR_PIN_LOCKED:
    error("PKCS#11 login failed: PIN locked");
    return -1;
  default:
    error("PKCS#11 login failed: error %lu", rv);
    return -1;
  }
  si->logged_in = 1;
  return (0);
}

static int
pkcs11_login(struct pkcs11_key *k11, CK_USER_TYPE type)
{
  if (k11 == NULL || k11->provider == NULL || !k11->provider->valid) {
    error("no pkcs11 (valid) provider found");
    return (-1);
  }

  return pkcs11_login_slot(k11->provider,
      &k11->provider->slotinfo[k11->slotidx], type);
}


static int
pkcs11_check_obj_bool_attrib(struct pkcs11_key *k11, CK_OBJECT_HANDLE obj,
    CK_ATTRIBUTE_TYPE type, int *val)
{
  struct pkcs11_slotinfo  *si;
  CK_FUNCTION_LIST  *f;
  CK_BBOOL    flag = 0;
  CK_ATTRIBUTE    attr;
  CK_RV      rv;

  *val = 0;

  if (!k11->provider || !k11->provider->valid) {
    error("no pkcs11 (valid) provider found");
    return (-1);
  }

  f = k11->provider->function_list;
  si = &k11->provider->slotinfo[k11->slotidx];

  attr.type = type;
  attr.pValue = &flag;
  attr.ulValueLen = sizeof(flag);

  rv = f->C_GetAttributeValue(si->session, obj, &attr, 1);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    return (-1);
  }
  *val = flag != 0;
  debug_f("provider \"%s\" slot %lu object %lu: attrib %lu = %d",
      k11->provider->name, k11->slotidx, obj, type, *val);
  return (0);
}

static int
pkcs11_get_key(struct pkcs11_key *k11, CK_MECHANISM_TYPE mech_type)
{
  struct pkcs11_slotinfo  *si;
  CK_FUNCTION_LIST  *f;
  CK_OBJECT_HANDLE   obj;
  CK_RV      rv;
  CK_OBJECT_CLASS    private_key_class;
  CK_BBOOL     true_val;
  CK_MECHANISM     mech;
  CK_ATTRIBUTE     key_filter[3];
  int      always_auth = 0;
  int      did_login = 0;

  if (!k11->provider || !k11->provider->valid) {
    error("no pkcs11 (valid) provider found");
    return (-1);
  }

  f = k11->provider->function_list;
  si = &k11->provider->slotinfo[k11->slotidx];

  if ((si->token.flags & CKF_LOGIN_REQUIRED) && !si->logged_in) {
    if (pkcs11_login(k11, CKU_USER) < 0) {
      error("login failed");
      return (-1);
    }
    did_login = 1;
  }

  memset(&key_filter, 0, sizeof(key_filter));
  private_key_class = CKO_PRIVATE_KEY;
  key_filter[0].type = CKA_CLASS;
  key_filter[0].pValue = &private_key_class;
  key_filter[0].ulValueLen = sizeof(private_key_class);

  key_filter[1].type = CKA_ID;
  key_filter[1].pValue = k11->keyid;
  key_filter[1].ulValueLen = k11->keyid_len;

  true_val = CK_TRUE;
  key_filter[2].type = CKA_SIGN;
  key_filter[2].pValue = &true_val;
  key_filter[2].ulValueLen = sizeof(true_val);

  /* try to find object w/CKA_SIGN first, retry w/o */
  if (pkcs11_find(k11->provider, k11->slotidx, key_filter, 3, &obj) < 0 &&
      pkcs11_find(k11->provider, k11->slotidx, key_filter, 2, &obj) < 0) {
    error("cannot find private key");
    return (-1);
  }

  memset(&mech, 0, sizeof(mech));
  mech.mechanism = mech_type;
  mech.pParameter = NULL_PTR;
  mech.ulParameterLen = 0;

  if ((rv = f->C_SignInit(si->session, &mech, obj)) != CKR_OK) {
    error("C_SignInit failed: %lu", rv);
    return (-1);
  }

  pkcs11_check_obj_bool_attrib(k11, obj, CKA_ALWAYS_AUTHENTICATE,
      &always_auth); /* ignore errors here */
  if (always_auth && !did_login) {
    debug_f("always-auth key");
    if (pkcs11_login(k11, CKU_CONTEXT_SPECIFIC) < 0) {
      error("login failed for always-auth key");
      return (-1);
    }
  }

  return (0);
}

/* openssl callback doing the actual signing operation */
static int
pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
    int padding)
{
  struct pkcs11_key *k11;
  struct pkcs11_slotinfo  *si;
  CK_FUNCTION_LIST  *f;
  CK_ULONG    tlen = 0;
  CK_RV     rv;
  int     rval = -1;

  if ((k11 = RSA_get_ex_data(rsa, rsa_idx)) == NULL) {
    error("RSA_get_ex_data failed");
    return (-1);
  }

  if (pkcs11_get_key(k11, CKM_RSA_PKCS) == -1) {
    error("pkcs11_get_key failed");
    return (-1);
  }

  f = k11->provider->function_list;
  si = &k11->provider->slotinfo[k11->slotidx];
  tlen = RSA_size(rsa);

  /* XXX handle CKR_BUFFER_TOO_SMALL */
  rv = f->C_Sign(si->session, (CK_BYTE *)from, flen, to, &tlen);
  if (rv == CKR_OK)
    rval = tlen;
  else
    error("C_Sign failed: %lu", rv);

  return (rval);
}

static int
pkcs11_rsa_private_decrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
    int padding)
{
  return (-1);
}

static int
pkcs11_rsa_start_wrapper(void)
{
  if (rsa_method != NULL)
    return (0);
  rsa_method = RSA_meth_dup(RSA_get_default_method());
  if (rsa_method == NULL)
    return (-1);
  rsa_idx = RSA_get_ex_new_index(0, "ssh-pkcs11-rsa",
      NULL, NULL, pkcs11_k11_free);
  if (rsa_idx == -1)
    return (-1);
  if (!RSA_meth_set1_name(rsa_method, "pkcs11") ||
      !RSA_meth_set_priv_enc(rsa_method, pkcs11_rsa_private_encrypt) ||
      !RSA_meth_set_priv_dec(rsa_method, pkcs11_rsa_private_decrypt)) {
    error_f("setup pkcs11 method failed");
    return (-1);
  }
  return (0);
}

/* redirect private key operations for rsa key to pkcs11 token */
static int
pkcs11_rsa_wrap(struct pkcs11_provider *provider, CK_ULONG slotidx,
    CK_ATTRIBUTE *keyid_attrib, RSA *rsa)
{
  struct pkcs11_key *k11;

  if (pkcs11_rsa_start_wrapper() == -1)
    return (-1);

  k11 = xcalloc(1, sizeof(*k11));
  k11->provider = provider;
  provider->refcount++; /* provider referenced by RSA key */
  k11->slotidx = slotidx;
  /* identify key object on smartcard */
  k11->keyid_len = keyid_attrib->ulValueLen;
  if (k11->keyid_len > 0) {
    k11->keyid = xmalloc(k11->keyid_len);
    memcpy(k11->keyid, keyid_attrib->pValue, k11->keyid_len);
  }

  if (RSA_set_method(rsa, rsa_method) != 1)
    fatal_f("RSA_set_method failed");
  if (RSA_set_ex_data(rsa, rsa_idx, k11) != 1)
    fatal_f("RSA_set_ex_data failed");
  return (0);
}

#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
/* openssl callback doing the actual signing operation */
static ECDSA_SIG *
ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
    const BIGNUM *rp, EC_KEY *ec)
{
  struct pkcs11_key *k11;
  struct pkcs11_slotinfo  *si;
  CK_FUNCTION_LIST  *f;
  CK_ULONG    siglen = 0, bnlen;
  CK_RV     rv;
  ECDSA_SIG   *ret = NULL;
  u_char      *sig;
  BIGNUM      *r = NULL, *s = NULL;

  if ((k11 = EC_KEY_get_ex_data(ec, ec_key_idx)) == NULL) {
    ossl_error("EC_KEY_get_ex_data failed for ec");
    return (NULL);
  }

  if (pkcs11_get_key(k11, CKM_ECDSA) == -1) {
    error("pkcs11_get_key failed");
    return (NULL);
  }

  f = k11->provider->function_list;
  si = &k11->provider->slotinfo[k11->slotidx];

  siglen = ECDSA_size(ec);
  sig = xmalloc(siglen);

  /* XXX handle CKR_BUFFER_TOO_SMALL */
  rv = f->C_Sign(si->session, (CK_BYTE *)dgst, dgst_len, sig, &siglen);
  if (rv != CKR_OK) {
    error("C_Sign failed: %lu", rv);
    goto done;
  }
  if (siglen < 64 || siglen > 132 || siglen % 2) {
    error_f("bad signature length: %lu", (u_long)siglen);
    goto done;
  }
  bnlen = siglen/2;
  if ((ret = ECDSA_SIG_new()) == NULL) {
    error("ECDSA_SIG_new failed");
    goto done;
  }
  if ((r = BN_bin2bn(sig, bnlen, NULL)) == NULL ||
      (s = BN_bin2bn(sig+bnlen, bnlen, NULL)) == NULL) {
    ossl_error("BN_bin2bn failed");
    ECDSA_SIG_free(ret);
    ret = NULL;
    goto done;
  }
  if (!ECDSA_SIG_set0(ret, r, s)) {
    error_f("ECDSA_SIG_set0 failed");
    ECDSA_SIG_free(ret);
    ret = NULL;
    goto done;
  }
  r = s = NULL; /* now owned by ret */
  /* success */
 done:
  BN_free(r);
  BN_free(s);
  free(sig);

  return (ret);
}

static int
pkcs11_ecdsa_start_wrapper(void)
{
  int (*orig_sign)(int, const unsigned char *, int, unsigned char *,
      unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;

  if (ec_key_method != NULL)
    return (0);
  ec_key_idx = EC_KEY_get_ex_new_index(0, "ssh-pkcs11-ecdsa",
      NULL, NULL, pkcs11_k11_free);
  if (ec_key_idx == -1)
    return (-1);
  ec_key_method = EC_KEY_METHOD_new(EC_KEY_OpenSSL());
  if (ec_key_method == NULL)
    return (-1);
  EC_KEY_METHOD_get_sign(ec_key_method, &orig_sign, NULL, NULL);
  EC_KEY_METHOD_set_sign(ec_key_method, orig_sign, NULL, ecdsa_do_sign);
  return (0);
}

static int
pkcs11_ecdsa_wrap(struct pkcs11_provider *provider, CK_ULONG slotidx,
    CK_ATTRIBUTE *keyid_attrib, EC_KEY *ec)
{
  struct pkcs11_key *k11;

  if (pkcs11_ecdsa_start_wrapper() == -1)
    return (-1);

  k11 = xcalloc(1, sizeof(*k11));
  k11->provider = provider;
  provider->refcount++; /* provider referenced by ECDSA key */
  k11->slotidx = slotidx;
  /* identify key object on smartcard */
  k11->keyid_len = keyid_attrib->ulValueLen;
  if (k11->keyid_len > 0) {
    k11->keyid = xmalloc(k11->keyid_len);
    memcpy(k11->keyid, keyid_attrib->pValue, k11->keyid_len);
  }
  if (EC_KEY_set_method(ec, ec_key_method) != 1)
    fatal_f("EC_KEY_set_method failed");
  if (EC_KEY_set_ex_data(ec, ec_key_idx, k11) != 1)
    fatal_f("EC_KEY_set_ex_data failed");

  return (0);
}
#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */

/* remove trailing spaces */
static char *
rmspace(u_char *buf, size_t len)
{
  size_t i;

  if (len == 0)
    return buf;
  for (i = len - 1; i > 0; i--)
    if (buf[i] == ' ')
      buf[i] = '\0';
    else
      break;
  return buf;
}
/* Used to printf fixed-width, space-padded, unterminated strings using %.*s */
#define RMSPACE(s) (int)sizeof(s), rmspace(s, sizeof(s))

/*
 * open a pkcs11 session and login if required.
 * if pin == NULL we delay login until key use
 */
static int
pkcs11_open_session(struct pkcs11_provider *p, CK_ULONG slotidx, char *pin,
    CK_ULONG user)
{
  struct pkcs11_slotinfo  *si;
  CK_FUNCTION_LIST  *f;
  CK_RV     rv;
  CK_SESSION_HANDLE session;
  int     login_required, ret;

  f = p->function_list;
  si = &p->slotinfo[slotidx];

  login_required = si->token.flags & CKF_LOGIN_REQUIRED;

  /* fail early before opening session */
  if (login_required && !pkcs11_interactive &&
      (pin == NULL || strlen(pin) == 0)) {
    error("pin required");
    return (-SSH_PKCS11_ERR_PIN_REQUIRED);
  }
  if ((rv = f->C_OpenSession(p->slotlist[slotidx], CKF_RW_SESSION|
      CKF_SERIAL_SESSION, NULL, NULL, &session)) != CKR_OK) {
    error("C_OpenSession failed: %lu", rv);
    return (-1);
  }
  if (login_required && pin != NULL && strlen(pin) != 0) {
    rv = f->C_Login(session, user, (u_char *)pin, strlen(pin));
    if (rv != CKR_OK && rv != CKR_USER_ALREADY_LOGGED_IN) {
      error("C_Login failed: %lu", rv);
      ret = (rv == CKR_PIN_LOCKED) ?
          -SSH_PKCS11_ERR_PIN_LOCKED :
          -SSH_PKCS11_ERR_LOGIN_FAIL;
      if ((rv = f->C_CloseSession(session)) != CKR_OK)
        error("C_CloseSession failed: %lu", rv);
      return (ret);
    }
    si->logged_in = 1;
  }
  si->session = session;
  return (0);
}

static int
pkcs11_key_included(struct sshkey ***keysp, int *nkeys, struct sshkey *key)
{
  int i;

  for (i = 0; i < *nkeys; i++)
    if (sshkey_equal(key, (*keysp)[i]))
      return (1);
  return (0);
}

#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
static struct sshkey *
pkcs11_fetch_ecdsa_pubkey(struct pkcs11_provider *p, CK_ULONG slotidx,
    CK_OBJECT_HANDLE *obj)
{
  CK_ATTRIBUTE     key_attr[3];
  CK_SESSION_HANDLE  session;
  CK_FUNCTION_LIST  *f = NULL;
  CK_RV      rv;
  ASN1_OCTET_STRING *octet = NULL;
  EC_KEY      *ec = NULL;
  EC_GROUP    *group = NULL;
  struct sshkey   *key = NULL;
  const unsigned char *attrp = NULL;
  int      i;
  int      nid;

  memset(&key_attr, 0, sizeof(key_attr));
  key_attr[0].type = CKA_ID;
  key_attr[1].type = CKA_EC_POINT;
  key_attr[2].type = CKA_EC_PARAMS;

  session = p->slotinfo[slotidx].session;
  f = p->function_list;

  /* figure out size of the attributes */
  rv = f->C_GetAttributeValue(session, *obj, key_attr, 3);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    return (NULL);
  }

  /*
   * Allow CKA_ID (always first attribute) to be empty, but
   * ensure that none of the others are zero length.
   * XXX assumes CKA_ID is always first.
   */
  if (key_attr[1].ulValueLen == 0 ||
      key_attr[2].ulValueLen == 0) {
    error("invalid attribute length");
    return (NULL);
  }

  /* allocate buffers for attributes */
  for (i = 0; i < 3; i++)
    if (key_attr[i].ulValueLen > 0)
      key_attr[i].pValue = xcalloc(1, key_attr[i].ulValueLen);

  /* retrieve ID, public point and curve parameters of EC key */
  rv = f->C_GetAttributeValue(session, *obj, key_attr, 3);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    goto fail;
  }

  ec = EC_KEY_new();
  if (ec == NULL) {
    error("EC_KEY_new failed");
    goto fail;
  }

  attrp = key_attr[2].pValue;
  group = d2i_ECPKParameters(NULL, &attrp, key_attr[2].ulValueLen);
  if (group == NULL) {
    ossl_error("d2i_ECPKParameters failed");
    goto fail;
  }

  if (EC_KEY_set_group(ec, group) == 0) {
    ossl_error("EC_KEY_set_group failed");
    goto fail;
  }

  if (key_attr[1].ulValueLen <= 2) {
    error("CKA_EC_POINT too small");
    goto fail;
  }

  attrp = key_attr[1].pValue;
  octet = d2i_ASN1_OCTET_STRING(NULL, &attrp, key_attr[1].ulValueLen);
  if (octet == NULL) {
    ossl_error("d2i_ASN1_OCTET_STRING failed");
    goto fail;
  }
  attrp = octet->data;
  if (o2i_ECPublicKey(&ec, &attrp, octet->length) == NULL) {
    ossl_error("o2i_ECPublicKey failed");
    goto fail;
  }

  nid = sshkey_ecdsa_key_to_nid(ec);
  if (nid < 0) {
    error("couldn't get curve nid");
    goto fail;
  }

  if (pkcs11_ecdsa_wrap(p, slotidx, &key_attr[0], ec))
    goto fail;

  key = sshkey_new(KEY_UNSPEC);
  if (key == NULL) {
    error("sshkey_new failed");
    goto fail;
  }

  EVP_PKEY_free(key->pkey);
  if ((key->pkey = EVP_PKEY_new()) == NULL)
    fatal("EVP_PKEY_new failed");
  if (EVP_PKEY_set1_EC_KEY(key->pkey, ec) != 1)
    fatal("EVP_PKEY_set1_EC_KEY failed");
  key->ecdsa_nid = nid;
  key->type = KEY_ECDSA;
  key->flags |= SSHKEY_FLAG_EXT;

fail:
  for (i = 0; i < 3; i++)
    free(key_attr[i].pValue);
  if (ec)
    EC_KEY_free(ec);
  if (group)
    EC_GROUP_free(group);
  if (octet)
    ASN1_OCTET_STRING_free(octet);

  return (key);
}
#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */

static struct sshkey *
pkcs11_fetch_rsa_pubkey(struct pkcs11_provider *p, CK_ULONG slotidx,
    CK_OBJECT_HANDLE *obj)
{
  CK_ATTRIBUTE     key_attr[3];
  CK_SESSION_HANDLE  session;
  CK_FUNCTION_LIST  *f = NULL;
  CK_RV      rv;
  RSA     *rsa = NULL;
  BIGNUM      *rsa_n, *rsa_e;
  struct sshkey   *key = NULL;
  int      i;

  memset(&key_attr, 0, sizeof(key_attr));
  key_attr[0].type = CKA_ID;
  key_attr[1].type = CKA_MODULUS;
  key_attr[2].type = CKA_PUBLIC_EXPONENT;

  session = p->slotinfo[slotidx].session;
  f = p->function_list;

  /* figure out size of the attributes */
  rv = f->C_GetAttributeValue(session, *obj, key_attr, 3);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    return (NULL);
  }

  /*
   * Allow CKA_ID (always first attribute) to be empty, but
   * ensure that none of the others are zero length.
   * XXX assumes CKA_ID is always first.
   */
  if (key_attr[1].ulValueLen == 0 ||
      key_attr[2].ulValueLen == 0) {
    error("invalid attribute length");
    return (NULL);
  }

  /* allocate buffers for attributes */
  for (i = 0; i < 3; i++)
    if (key_attr[i].ulValueLen > 0)
      key_attr[i].pValue = xcalloc(1, key_attr[i].ulValueLen);

  /* retrieve ID, modulus and public exponent of RSA key */
  rv = f->C_GetAttributeValue(session, *obj, key_attr, 3);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    goto fail;
  }

  rsa = RSA_new();
  if (rsa == NULL) {
    error("RSA_new failed");
    goto fail;
  }

  rsa_n = BN_bin2bn(key_attr[1].pValue, key_attr[1].ulValueLen, NULL);
  rsa_e = BN_bin2bn(key_attr[2].pValue, key_attr[2].ulValueLen, NULL);
  if (rsa_n == NULL || rsa_e == NULL) {
    error("BN_bin2bn failed");
    goto fail;
  }
  if (!RSA_set0_key(rsa, rsa_n, rsa_e, NULL))
    fatal_f("set key");
  rsa_n = rsa_e = NULL; /* transferred */

  if (pkcs11_rsa_wrap(p, slotidx, &key_attr[0], rsa))
    goto fail;

  key = sshkey_new(KEY_UNSPEC);
  if (key == NULL) {
    error("sshkey_new failed");
    goto fail;
  }

  EVP_PKEY_free(key->pkey);
  if ((key->pkey = EVP_PKEY_new()) == NULL)
    fatal("EVP_PKEY_new failed");
  if (EVP_PKEY_set1_RSA(key->pkey, rsa) != 1)
    fatal("EVP_PKEY_set1_RSA failed");
  key->type = KEY_RSA;
  key->flags |= SSHKEY_FLAG_EXT;

fail:
  for (i = 0; i < 3; i++)
    free(key_attr[i].pValue);
  RSA_free(rsa);

  return (key);
}

static int
pkcs11_fetch_x509_pubkey(struct pkcs11_provider *p, CK_ULONG slotidx,
    CK_OBJECT_HANDLE *obj, struct sshkey **keyp, char **labelp)
{
  CK_ATTRIBUTE     cert_attr[3];
  CK_SESSION_HANDLE  session;
  CK_FUNCTION_LIST  *f = NULL;
  CK_RV      rv;
  X509      *x509 = NULL;
  X509_NAME   *x509_name = NULL;
  EVP_PKEY    *evp;
  RSA     *rsa = NULL;
#ifdef OPENSSL_HAS_ECC
  EC_KEY      *ec = NULL;
#endif
  struct sshkey   *key = NULL;
  int      i;
#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
  int      nid;
#endif
  const u_char    *cp;
  char      *subject = NULL;

  *keyp = NULL;
  *labelp = NULL;

  memset(&cert_attr, 0, sizeof(cert_attr));
  cert_attr[0].type = CKA_ID;
  cert_attr[1].type = CKA_SUBJECT;
  cert_attr[2].type = CKA_VALUE;

  session = p->slotinfo[slotidx].session;
  f = p->function_list;

  /* figure out size of the attributes */
  rv = f->C_GetAttributeValue(session, *obj, cert_attr, 3);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    return -1;
  }

  /*
   * Allow CKA_ID (always first attribute) to be empty, but
   * ensure that none of the others are zero length.
   * XXX assumes CKA_ID is always first.
   */
  if (cert_attr[1].ulValueLen == 0 ||
      cert_attr[2].ulValueLen == 0) {
    error("invalid attribute length");
    return -1;
  }

  /* allocate buffers for attributes */
  for (i = 0; i < 3; i++)
    if (cert_attr[i].ulValueLen > 0)
      cert_attr[i].pValue = xcalloc(1, cert_attr[i].ulValueLen);

  /* retrieve ID, subject and value of certificate */
  rv = f->C_GetAttributeValue(session, *obj, cert_attr, 3);
  if (rv != CKR_OK) {
    error("C_GetAttributeValue failed: %lu", rv);
    goto out;
  }

  /* Decode DER-encoded cert subject */
  cp = cert_attr[1].pValue;
  if ((x509_name = d2i_X509_NAME(NULL, &cp,
      cert_attr[1].ulValueLen)) == NULL ||
      (subject = X509_NAME_oneline(x509_name, NULL, 0)) == NULL)
    subject = xstrdup("invalid subject");
  X509_NAME_free(x509_name);

  cp = cert_attr[2].pValue;
  if ((x509 = d2i_X509(NULL, &cp, cert_attr[2].ulValueLen)) == NULL) {
    error("d2i_x509 failed");
    goto out;
  }

  if ((evp = X509_get_pubkey(x509)) == NULL) {
    error("X509_get_pubkey failed");
    goto out;
  }

  if (EVP_PKEY_base_id(evp) == EVP_PKEY_RSA) {
    if (EVP_PKEY_get0_RSA(evp) == NULL) {
      error("invalid x509; no rsa key");
      goto out;
    }
    if ((rsa = RSAPublicKey_dup(EVP_PKEY_get0_RSA(evp))) == NULL) {
      error("RSAPublicKey_dup failed");
      goto out;
    }

    if (pkcs11_rsa_wrap(p, slotidx, &cert_attr[0], rsa))
      goto out;

    key = sshkey_new(KEY_UNSPEC);
    if (key == NULL) {
      error("sshkey_new failed");
      goto out;
    }

    EVP_PKEY_free(key->pkey);
    if ((key->pkey = EVP_PKEY_new()) == NULL)
      fatal("EVP_PKEY_new failed");
    if (EVP_PKEY_set1_RSA(key->pkey, rsa) != 1)
      fatal("EVP_PKEY_set1_RSA failed");
    key->type = KEY_RSA;
    key->flags |= SSHKEY_FLAG_EXT;
#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
  } else if (EVP_PKEY_base_id(evp) == EVP_PKEY_EC) {
    if (EVP_PKEY_get0_EC_KEY(evp) == NULL) {
      error("invalid x509; no ec key");
      goto out;
    }
    if ((ec = EC_KEY_dup(EVP_PKEY_get0_EC_KEY(evp))) == NULL) {
      error("EC_KEY_dup failed");
      goto out;
    }

    nid = sshkey_ecdsa_key_to_nid(ec);
    if (nid < 0) {
      error("couldn't get curve nid");
      goto out;
    }

    if (pkcs11_ecdsa_wrap(p, slotidx, &cert_attr[0], ec))
      goto out;

    key = sshkey_new(KEY_UNSPEC);
    if (key == NULL) {
      error("sshkey_new failed");
      goto out;
    }

    EVP_PKEY_free(key->pkey);
    if ((key->pkey = EVP_PKEY_new()) == NULL)
      fatal("EVP_PKEY_new failed");
    if (EVP_PKEY_set1_EC_KEY(key->pkey, ec) != 1)
      fatal("EVP_PKEY_set1_EC_KEY failed");
    key->ecdsa_nid = nid;
    key->type = KEY_ECDSA;
    key->flags |= SSHKEY_FLAG_EXT;
#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */
  } else {
    error("unknown certificate key type");
    goto out;
  }
 out:
  for (i = 0; i < 3; i++)
    free(cert_attr[i].pValue);
  X509_free(x509);
  RSA_free(rsa);
#ifdef OPENSSL_HAS_ECC
  EC_KEY_free(ec);
#endif
  if (key == NULL) {
    free(subject);
    return -1;
  }
  /* success */
  *keyp = key;
  *labelp = subject;
  return 0;
}

#if 0
static int
have_rsa_key(const RSA *rsa)
{
  const BIGNUM *rsa_n, *rsa_e;

  RSA_get0_key(rsa, &rsa_n, &rsa_e, NULL);
  return rsa_n != NULL && rsa_e != NULL;
}
#endif

static void
note_key(struct pkcs11_provider *p, CK_ULONG slotidx, const char *context,
    struct sshkey *key)
{
  char *fp;

  if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
      SSH_FP_DEFAULT)) == NULL) {
    error_f("sshkey_fingerprint failed");
    return;
  }
  debug2("%s: provider %s slot %lu: %s %s", context, p->name,
      (u_long)slotidx, sshkey_type(key), fp);
  free(fp);
}

/*
 * lookup certificates for token in slot identified by slotidx,
 * add 'wrapped' public keys to the 'keysp' array and increment nkeys.
 * keysp points to an (possibly empty) array with *nkeys keys.
 */
static int
pkcs11_fetch_certs(struct pkcs11_provider *p, CK_ULONG slotidx,
    struct sshkey ***keysp, char ***labelsp, int *nkeys)
{
  struct sshkey   *key = NULL;
  CK_OBJECT_CLASS    key_class;
  CK_ATTRIBUTE     key_attr[1];
  CK_SESSION_HANDLE  session;
  CK_FUNCTION_LIST  *f = NULL;
  CK_RV      rv;
  CK_OBJECT_HANDLE   obj;
  CK_ULONG     n = 0;
  int      ret = -1;
  char      *label;

  memset(&key_attr, 0, sizeof(key_attr));
  memset(&obj, 0, sizeof(obj));

  key_class = CKO_CERTIFICATE;
  key_attr[0].type = CKA_CLASS;
  key_attr[0].pValue = &key_class;
  key_attr[0].ulValueLen = sizeof(key_class);

  session = p->slotinfo[slotidx].session;
  f = p->function_list;

  rv = f->C_FindObjectsInit(session, key_attr, 1);
  if (rv != CKR_OK) {
    error("C_FindObjectsInit failed: %lu", rv);
    goto fail;
  }

  while (1) {
    CK_CERTIFICATE_TYPE ck_cert_type;

    rv = f->C_FindObjects(session, &obj, 1, &n);
    if (rv != CKR_OK) {
      error("C_FindObjects failed: %lu", rv);
      goto fail;
    }
    if (n == 0)
      break;

    memset(&ck_cert_type, 0, sizeof(ck_cert_type));
    memset(&key_attr, 0, sizeof(key_attr));
    key_attr[0].type = CKA_CERTIFICATE_TYPE;
    key_attr[0].pValue = &ck_cert_type;
    key_attr[0].ulValueLen = sizeof(ck_cert_type);

    rv = f->C_GetAttributeValue(session, obj, key_attr, 1);
    if (rv != CKR_OK) {
      error("C_GetAttributeValue failed: %lu", rv);
      goto fail;
    }

    key = NULL;
    label = NULL;
    switch (ck_cert_type) {
    case CKC_X_509:
      if (pkcs11_fetch_x509_pubkey(p, slotidx, &obj,
          &key, &label) != 0) {
        error("failed to fetch key");
        continue;
      }
      break;
    default:
      error("skipping unsupported certificate type %lu",
          ck_cert_type);
      continue;
    }
    note_key(p, slotidx, __func__, key);
    if (pkcs11_key_included(keysp, nkeys, key)) {
      debug2_f("key already included");
      sshkey_free(key);
    } else {
      /* expand key array and add key */
      *keysp = xrecallocarray(*keysp, *nkeys,
          *nkeys + 1, sizeof(struct sshkey *));
      (*keysp)[*nkeys] = key;
      if (labelsp != NULL) {
        *labelsp = xrecallocarray(*labelsp, *nkeys,
            *nkeys + 1, sizeof(char *));
        (*labelsp)[*nkeys] = xstrdup((char *)label);
      }
      *nkeys = *nkeys + 1;
      debug("have %d keys", *nkeys);
    }
  }

  ret = 0;
fail:
  rv = f->C_FindObjectsFinal(session);
  if (rv != CKR_OK) {
    error("C_FindObjectsFinal failed: %lu", rv);
    ret = -1;
  }

  return (ret);
}

/*
 * lookup public keys for token in slot identified by slotidx,
 * add 'wrapped' public keys to the 'keysp' array and increment nkeys.
 * keysp points to an (possibly empty) array with *nkeys keys.
 */
static int
pkcs11_fetch_keys(struct pkcs11_provider *p, CK_ULONG slotidx,
    struct sshkey ***keysp, char ***labelsp, int *nkeys)
{
  struct sshkey   *key = NULL;
  CK_OBJECT_CLASS    key_class;
  CK_ATTRIBUTE     key_attr[2];
  CK_SESSION_HANDLE  session;
  CK_FUNCTION_LIST  *f = NULL;
  CK_RV      rv;
  CK_OBJECT_HANDLE   obj;
  CK_ULONG     n = 0;
  int      ret = -1;

  memset(&key_attr, 0, sizeof(key_attr));
  memset(&obj, 0, sizeof(obj));

  key_class = CKO_PUBLIC_KEY;
  key_attr[0].type = CKA_CLASS;
  key_attr[0].pValue = &key_class;
  key_attr[0].ulValueLen = sizeof(key_class);

  session = p->slotinfo[slotidx].session;
  f = p->function_list;

  rv = f->C_FindObjectsInit(session, key_attr, 1);
  if (rv != CKR_OK) {
    error("C_FindObjectsInit failed: %lu", rv);
    goto fail;
  }

  while (1) {
    CK_KEY_TYPE ck_key_type;
    CK_UTF8CHAR label[256];

    rv = f->C_FindObjects(session, &obj, 1, &n);
    if (rv != CKR_OK) {
      error("C_FindObjects failed: %lu", rv);
      goto fail;
    }
    if (n == 0)
      break;

    memset(&ck_key_type, 0, sizeof(ck_key_type));
    memset(&key_attr, 0, sizeof(key_attr));
    key_attr[0].type = CKA_KEY_TYPE;
    key_attr[0].pValue = &ck_key_type;
    key_attr[0].ulValueLen = sizeof(ck_key_type);
    key_attr[1].type = CKA_LABEL;
    key_attr[1].pValue = &label;
    key_attr[1].ulValueLen = sizeof(label) - 1;

    rv = f->C_GetAttributeValue(session, obj, key_attr, 2);
    if (rv != CKR_OK) {
      error("C_GetAttributeValue failed: %lu", rv);
      goto fail;
    }

    label[key_attr[1].ulValueLen] = '\0';

    switch (ck_key_type) {
    case CKK_RSA:
      key = pkcs11_fetch_rsa_pubkey(p, slotidx, &obj);
      break;
#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
    case CKK_ECDSA:
      key = pkcs11_fetch_ecdsa_pubkey(p, slotidx, &obj);
      break;
#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */
    default:
      /* XXX print key type? */
      key = NULL;
      error("skipping unsupported key type");
    }

    if (key == NULL) {
      error("failed to fetch key");
      continue;
    }
    note_key(p, slotidx, __func__, key);
    if (pkcs11_key_included(keysp, nkeys, key)) {
      debug2_f("key already included");
      sshkey_free(key);
    } else {
      /* expand key array and add key */
      *keysp = xrecallocarray(*keysp, *nkeys,
          *nkeys + 1, sizeof(struct sshkey *));
      (*keysp)[*nkeys] = key;
      if (labelsp != NULL) {
        *labelsp = xrecallocarray(*labelsp, *nkeys,
            *nkeys + 1, sizeof(char *));
        (*labelsp)[*nkeys] = xstrdup((char *)label);
      }
      *nkeys = *nkeys + 1;
      debug("have %d keys", *nkeys);
    }
  }

  ret = 0;
fail:
  rv = f->C_FindObjectsFinal(session);
  if (rv != CKR_OK) {
    error("C_FindObjectsFinal failed: %lu", rv);
    ret = -1;
  }

  return (ret);
}

#ifdef WITH_PKCS11_KEYGEN
#define FILL_ATTR(attr, idx, typ, val, len) \
  { (attr[idx]).type=(typ); (attr[idx]).pValue=(val); (attr[idx]).ulValueLen=len; idx++; }

static struct sshkey *
pkcs11_rsa_generate_private_key(struct pkcs11_provider *p, CK_ULONG slotidx,
    char *label, CK_ULONG bits, CK_BYTE keyid, u_int32_t *err)
{
  struct pkcs11_slotinfo  *si;
  char      *plabel = label ? label : "";
  int      npub = 0, npriv = 0;
  CK_RV      rv;
  CK_FUNCTION_LIST  *f;
  CK_SESSION_HANDLE  session;
  CK_BBOOL     true_val = CK_TRUE, false_val = CK_FALSE;
  CK_OBJECT_HANDLE   pubKey, privKey;
  CK_ATTRIBUTE     tpub[16], tpriv[16];
  CK_MECHANISM     mech = {
      CKM_RSA_PKCS_KEY_PAIR_GEN, NULL_PTR, 0
  };
  CK_BYTE      pubExponent[] = {
      0x01, 0x00, 0x01 /* RSA_F4 in bytes */
  };
  pubkey_filter[0].pValue = &pubkey_class;
  cert_filter[0].pValue = &cert_class;

  *err = 0;

  FILL_ATTR(tpub, npub, CKA_TOKEN, &true_val, sizeof(true_val));
  FILL_ATTR(tpub, npub, CKA_LABEL, plabel, strlen(plabel));
  FILL_ATTR(tpub, npub, CKA_ENCRYPT, &false_val, sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_VERIFY, &true_val, sizeof(true_val));
  FILL_ATTR(tpub, npub, CKA_VERIFY_RECOVER, &false_val,
      sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_WRAP, &false_val, sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_DERIVE, &false_val, sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_MODULUS_BITS, &bits, sizeof(bits));
  FILL_ATTR(tpub, npub, CKA_PUBLIC_EXPONENT, pubExponent,
      sizeof(pubExponent));
  FILL_ATTR(tpub, npub, CKA_ID, &keyid, sizeof(keyid));

  FILL_ATTR(tpriv, npriv, CKA_TOKEN,  &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_LABEL,  plabel, strlen(plabel));
  FILL_ATTR(tpriv, npriv, CKA_PRIVATE,  &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_SENSITIVE,  &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_DECRYPT,  &false_val, sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_SIGN,  &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_SIGN_RECOVER,  &false_val,
      sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_UNWRAP,  &false_val, sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_DERIVE,  &false_val, sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_ID, &keyid, sizeof(keyid));

  f = p->function_list;
  si = &p->slotinfo[slotidx];
  session = si->session;

  if ((rv = f->C_GenerateKeyPair(session, &mech, tpub, npub, tpriv, npriv,
      &pubKey, &privKey)) != CKR_OK) {
    error_f("key generation failed: error 0x%lx", rv);
    *err = rv;
    return NULL;
  }

  return pkcs11_fetch_rsa_pubkey(p, slotidx, &pubKey);
}

static int
h2i(char c)
{
  if (c >= '0' && c <= '9')
    return c - '0';
  else if (c >= 'a' && c <= 'f')
    return c - 'a' + 10;
  else if (c >= 'A' && c <= 'F')
    return c - 'A' + 10;
  else
    return -1;
}

static int
pkcs11_decode_hex(const char *hex, unsigned char **dest, size_t *rlen)
{
  size_t  i, len;

  if (dest)
    *dest = NULL;
  if (rlen)
    *rlen = 0;

  if ((len = strlen(hex)) % 2)
    return -1;
  len /= 2;

  *dest = xmalloc(len);

  for (i = 0; i < len; i++) {
    int hi, low;

    hi = h2i(hex[2 * i]);
    lo = h2i(hex[(2 * i) + 1]);
    if (hi == -1 || lo == -1)
      return -1;
    (*dest)[i] = (hi << 4) | lo;
  }

  if (rlen)
    *rlen = len;

  return 0;
}

static struct ec_curve_info {
  const char  *name;
  const char  *oid;
  const char  *oid_encoded;
  size_t     size;
} ec_curve_infos[] = {
  {"prime256v1",  "1.2.840.10045.3.1.7",  "06082A8648CE3D030107", 256},
  {"secp384r1", "1.3.132.0.34",   "06052B81040022", 384},
  {"secp521r1", "1.3.132.0.35",   "06052B81040023", 521},
  {NULL,    NULL,     NULL,     0},
};

static struct sshkey *
pkcs11_ecdsa_generate_private_key(struct pkcs11_provider *p, CK_ULONG slotidx,
    char *label, CK_ULONG bits, CK_BYTE keyid, u_int32_t *err)
{
  struct pkcs11_slotinfo  *si;
  char      *plabel = label ? label : "";
  int      i;
  size_t       ecparams_size;
  unsigned char   *ecparams = NULL;
  int      npub = 0, npriv = 0;
  CK_RV      rv;
  CK_FUNCTION_LIST  *f;
  CK_SESSION_HANDLE  session;
  CK_BBOOL     true_val = CK_TRUE, false_val = CK_FALSE;
  CK_OBJECT_HANDLE   pubKey, privKey;
  CK_MECHANISM     mech = {
      CKM_EC_KEY_PAIR_GEN, NULL_PTR, 0
  };
  CK_ATTRIBUTE     tpub[16], tpriv[16];

  *err = 0;

  for (i = 0; ec_curve_infos[i].name; i++) {
    if (ec_curve_infos[i].size == bits)
      break;
  }
  if (!ec_curve_infos[i].name) {
    error_f("invalid key size %lu", bits);
    return NULL;
  }
  if (pkcs11_decode_hex(ec_curve_infos[i].oid_encoded, &ecparams,
      &ecparams_size) == -1) {
    error_f("invalid oid");
    return NULL;
  }

  FILL_ATTR(tpub, npub, CKA_TOKEN, &true_val, sizeof(true_val));
  FILL_ATTR(tpub, npub, CKA_LABEL, plabel, strlen(plabel));
  FILL_ATTR(tpub, npub, CKA_ENCRYPT, &false_val, sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_VERIFY, &true_val, sizeof(true_val));
  FILL_ATTR(tpub, npub, CKA_VERIFY_RECOVER, &false_val,
      sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_WRAP, &false_val, sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_DERIVE, &false_val, sizeof(false_val));
  FILL_ATTR(tpub, npub, CKA_EC_PARAMS, ecparams, ecparams_size);
  FILL_ATTR(tpub, npub, CKA_ID, &keyid, sizeof(keyid));

  FILL_ATTR(tpriv, npriv, CKA_TOKEN, &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_LABEL, plabel, strlen(plabel));
  FILL_ATTR(tpriv, npriv, CKA_PRIVATE, &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_SENSITIVE, &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_DECRYPT, &false_val, sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_SIGN, &true_val, sizeof(true_val));
  FILL_ATTR(tpriv, npriv, CKA_SIGN_RECOVER, &false_val,
      sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_UNWRAP, &false_val, sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_DERIVE, &false_val, sizeof(false_val));
  FILL_ATTR(tpriv, npriv, CKA_ID, &keyid, sizeof(keyid));

  f = p->function_list;
  si = &p->slotinfo[slotidx];
  session = si->session;

  if ((rv = f->C_GenerateKeyPair(session, &mech, tpub, npub, tpriv, npriv,
      &pubKey, &privKey)) != CKR_OK) {
    error_f("key generation failed: error 0x%lx", rv);
    *err = rv;
    return NULL;
  }

  return pkcs11_fetch_ecdsa_pubkey(p, slotidx, &pubKey);
}
#endif /* WITH_PKCS11_KEYGEN */

/*
 * register a new provider, fails if provider already exists. if
 * keyp is provided, fetch keys.
 */
static int
pkcs11_register_provider(char *provider_id, char *pin,
    struct sshkey ***keyp, char ***labelsp,
    struct pkcs11_provider **providerp, CK_ULONG user)
{
  int nkeys, need_finalize = 0;
  int ret = -1;
  struct pkcs11_provider *p = NULL;
  void *handle = NULL;
  CK_RV (*getfunctionlist)(CK_FUNCTION_LIST **);
  CK_RV rv;
  CK_FUNCTION_LIST *f = NULL;
  CK_TOKEN_INFO *token;
  CK_ULONG i;

  if (providerp == NULL)
    goto fail;
  *providerp = NULL;

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

  if (pkcs11_provider_lookup(provider_id) != NULL) {
    debug_f("provider already registered: %s", provider_id);
    goto fail;
  }
  if (lib_contains_symbol(provider_id, "C_GetFunctionList") != 0) {
    error("provider %s is not a PKCS11 library", provider_id);
    goto fail;
  }
  /* open shared pkcs11-library */
  if ((handle = dlopen(provider_id, RTLD_NOW)) == NULL) {
    error("dlopen %s failed: %s", provider_id, dlerror());
    goto fail;
  }
  if ((getfunctionlist = dlsym(handle, "C_GetFunctionList")) == NULL)
    fatal("dlsym(C_GetFunctionList) failed: %s", dlerror());
  p = xcalloc(1, sizeof(*p));
  p->name = xstrdup(provider_id);
  p->handle = handle;
  /* setup the pkcs11 callbacks */
  if ((rv = (*getfunctionlist)(&f)) != CKR_OK) {
    error("C_GetFunctionList for provider %s failed: %lu",
        provider_id, rv);
    goto fail;
  }
  p->function_list = f;
  if ((rv = f->C_Initialize(NULL)) != CKR_OK) {
    error("C_Initialize for provider %s failed: %lu",
        provider_id, rv);
    goto fail;
  }
  need_finalize = 1;
  if ((rv = f->C_GetInfo(&p->info)) != CKR_OK) {
    error("C_GetInfo for provider %s failed: %lu",
        provider_id, rv);
    goto fail;
  }
  debug("provider %s: manufacturerID <%.*s> cryptokiVersion %d.%d"
      " libraryDescription <%.*s> libraryVersion %d.%d",
      provider_id,
      RMSPACE(p->info.manufacturerID),
      p->info.cryptokiVersion.major,
      p->info.cryptokiVersion.minor,
      RMSPACE(p->info.libraryDescription),
      p->info.libraryVersion.major,
      p->info.libraryVersion.minor);
  if ((rv = f->C_GetSlotList(CK_TRUE, NULL, &p->nslots)) != CKR_OK) {
    error("C_GetSlotList failed: %lu", rv);
    goto fail;
  }
  if (p->nslots == 0) {
    debug_f("provider %s returned no slots", provider_id);
    ret = -SSH_PKCS11_ERR_NO_SLOTS;
    goto fail;
  }
  p->slotlist = xcalloc(p->nslots, sizeof(CK_SLOT_ID));
  if ((rv = f->C_GetSlotList(CK_TRUE, p->slotlist, &p->nslots))
      != CKR_OK) {
    error("C_GetSlotList for provider %s failed: %lu",
        provider_id, rv);
    goto fail;
  }
  p->slotinfo = xcalloc(p->nslots, sizeof(struct pkcs11_slotinfo));
  p->valid = 1;
  nkeys = 0;
  for (i = 0; i < p->nslots; i++) {
    token = &p->slotinfo[i].token;
    if ((rv = f->C_GetTokenInfo(p->slotlist[i], token))
        != CKR_OK) {
      error("C_GetTokenInfo for provider %s slot %lu "
          "failed: %lu", provider_id, (u_long)i, rv);
      continue;
    }
    if ((token->flags & CKF_TOKEN_INITIALIZED) == 0) {
      debug2_f("ignoring uninitialised token in "
          "provider %s slot %lu", provider_id, (u_long)i);
      continue;
    }
    debug("provider %s slot %lu: label <%.*s> "
        "manufacturerID <%.*s> model <%.*s> serial <%.*s> "
        "flags 0x%lx",
        provider_id, (unsigned long)i,
        RMSPACE(token->label), RMSPACE(token->manufacturerID),
        RMSPACE(token->model), RMSPACE(token->serialNumber),
        token->flags);
    /*
     * open session, login with pin and retrieve public
     * keys (if keyp is provided)
     */
    if ((ret = pkcs11_open_session(p, i, pin, user)) != 0 ||
        keyp == NULL)
      continue;
    pkcs11_fetch_keys(p, i, keyp, labelsp, &nkeys);
    pkcs11_fetch_certs(p, i, keyp, labelsp, &nkeys);
    if (nkeys == 0 && !p->slotinfo[i].logged_in &&
        pkcs11_interactive) {
      /*
       * Some tokens require login before they will
       * expose keys.
       */
      if (pkcs11_login_slot(p, &p->slotinfo[i],
          CKU_USER) < 0) {
        error("login failed");
        continue;
      }
      pkcs11_fetch_keys(p, i, keyp, labelsp, &nkeys);
      pkcs11_fetch_certs(p, i, keyp, labelsp, &nkeys);
    }
  }

  /* now owned by caller */
  *providerp = p;

  TAILQ_INSERT_TAIL(&pkcs11_providers, p, next);
  p->refcount++;  /* add to provider list */

  return (nkeys);
fail:
  if (need_finalize && (rv = f->C_Finalize(NULL)) != CKR_OK)
    error("C_Finalize for provider %s failed: %lu",
        provider_id, rv);
  if (p) {
    free(p->name);
    free(p->slotlist);
    free(p->slotinfo);
    free(p);
  }
  if (handle)
    dlclose(handle);
  if (ret > 0)
    ret = -1;
  return (ret);
}

/*
 * register a new provider and get number of keys hold by the token,
 * fails if provider already exists
 */
int
pkcs11_add_provider(char *provider_id, char *pin, struct sshkey ***keyp,
    char ***labelsp)
{
  struct pkcs11_provider *p = NULL;
  int nkeys;

  nkeys = pkcs11_register_provider(provider_id, pin, keyp, labelsp,
      &p, CKU_USER);

  /* no keys found or some other error, de-register provider */
  if (nkeys <= 0 && p != NULL) {
    TAILQ_REMOVE(&pkcs11_providers, p, next);
    pkcs11_provider_finalize(p);
    pkcs11_provider_unref(p);
  }
  if (nkeys == 0)
    debug_f("provider %s returned no keys", provider_id);

  return (nkeys);
}

#ifdef WITH_PKCS11_KEYGEN
struct sshkey *
pkcs11_gakp(char *provider_id, char *pin, unsigned int slotidx, char *label,
    unsigned int type, unsigned int bits, unsigned char keyid, u_int32_t *err)
{
  struct pkcs11_provider  *p = NULL;
  struct pkcs11_slotinfo  *si;
  CK_FUNCTION_LIST  *f;
  CK_SESSION_HANDLE  session;
  struct sshkey   *k = NULL;
  int      ret = -1, reset_pin = 0, reset_provider = 0;
  CK_RV      rv;

  *err = 0;

  if ((p = pkcs11_provider_lookup(provider_id)) != NULL)
    debug_f("provider \"%s\" available", provider_id);
  else if ((ret = pkcs11_register_provider(provider_id, pin, NULL, NULL,
      &p, CKU_SO)) < 0) {
    debug_f("could not register provider %s", provider_id);
    goto out;
  } else
    reset_provider = 1;

  f = p->function_list;
  si = &p->slotinfo[slotidx];
  session = si->session;

  if ((rv = f->C_SetOperationState(session , pin, strlen(pin),
      CK_INVALID_HANDLE, CK_INVALID_HANDLE)) != CKR_OK) {
    debug_f("could not supply SO pin: %lu", rv);
    reset_pin = 0;
  } else
    reset_pin = 1;

  switch (type) {
  case KEY_RSA:
    if ((k = pkcs11_rsa_generate_private_key(p, slotidx, label,
        bits, keyid, err)) == NULL) {
      debug_f("failed to generate RSA key");
      goto out;
    }
    break;
  case KEY_ECDSA:
    if ((k = pkcs11_ecdsa_generate_private_key(p, slotidx, label,
        bits, keyid, err)) == NULL) {
      debug_f("failed to generate ECDSA key");
      goto out;
    }
    break;
  default:
    *err = SSH_PKCS11_ERR_GENERIC;
    debug_f("unknown type %d", type);
    goto out;
  }

out:
  if (reset_pin)
    f->C_SetOperationState(session , NULL, 0, CK_INVALID_HANDLE,
        CK_INVALID_HANDLE);

  if (reset_provider)
    pkcs11_del_provider(provider_id);

  return (k);
}

struct sshkey *
pkcs11_destroy_keypair(char *provider_id, char *pin, unsigned long slotidx,
    unsigned char keyid, u_int32_t *err)
{
  struct pkcs11_provider  *p = NULL;
  struct pkcs11_slotinfo  *si;
  struct sshkey   *k = NULL;
  int      reset_pin = 0, reset_provider = 0;
  CK_ULONG     nattrs;
  CK_FUNCTION_LIST  *f;
  CK_SESSION_HANDLE  session;
  CK_ATTRIBUTE     attrs[16];
  CK_OBJECT_CLASS    key_class;
  CK_KEY_TYPE    key_type;
  CK_OBJECT_HANDLE   obj = CK_INVALID_HANDLE;
  CK_RV      rv;

  *err = 0;

  if ((p = pkcs11_provider_lookup(provider_id)) != NULL) {
    debug_f("using provider \"%s\"", provider_id);
  } else if (pkcs11_register_provider(provider_id, pin, NULL, NULL, &p,
      CKU_SO) < 0) {
    debug_f("could not register provider %s",
        provider_id);
    goto out;
  } else
    reset_provider = 1;

  f = p->function_list;
  si = &p->slotinfo[slotidx];
  session = si->session;

  if ((rv = f->C_SetOperationState(session , pin, strlen(pin),
      CK_INVALID_HANDLE, CK_INVALID_HANDLE)) != CKR_OK) {
    debug_f("could not supply SO pin: %lu", rv);
    reset_pin = 0;
  } else
    reset_pin = 1;

  /* private key */
  nattrs = 0;
  key_class = CKO_PRIVATE_KEY;
  FILL_ATTR(attrs, nattrs, CKA_CLASS, &key_class, sizeof(key_class));
  FILL_ATTR(attrs, nattrs, CKA_ID, &keyid, sizeof(keyid));

  if (pkcs11_find(p, slotidx, attrs, nattrs, &obj) == 0 &&
      obj != CK_INVALID_HANDLE) {
    if ((rv = f->C_DestroyObject(session, obj)) != CKR_OK) {
      debug_f("could not destroy private key 0x%hhx",
          keyid);
      *err = rv;
      goto out;
    }
  }

  /* public key */
  nattrs = 0;
  key_class = CKO_PUBLIC_KEY;
  FILL_ATTR(attrs, nattrs, CKA_CLASS, &key_class, sizeof(key_class));
  FILL_ATTR(attrs, nattrs, CKA_ID, &keyid, sizeof(keyid));

  if (pkcs11_find(p, slotidx, attrs, nattrs, &obj) == 0 &&
      obj != CK_INVALID_HANDLE) {

    /* get key type */
    nattrs = 0;
    FILL_ATTR(attrs, nattrs, CKA_KEY_TYPE, &key_type,
        sizeof(key_type));
    rv = f->C_GetAttributeValue(session, obj, attrs, nattrs);
    if (rv != CKR_OK) {
      debug_f("could not get key type of public key 0x%hhx",
          keyid);
      *err = rv;
      key_type = -1;
    }
    if (key_type == CKK_RSA)
      k = pkcs11_fetch_rsa_pubkey(p, slotidx, &obj);
    else if (key_type == CKK_ECDSA)
      k = pkcs11_fetch_ecdsa_pubkey(p, slotidx, &obj);

    if ((rv = f->C_DestroyObject(session, obj)) != CKR_OK) {
      debug_f("could not destroy public key 0x%hhx", keyid);
      *err = rv;
      goto out;
    }
  }

out:
  if (reset_pin)
    f->C_SetOperationState(session , NULL, 0, CK_INVALID_HANDLE,
        CK_INVALID_HANDLE);

  if (reset_provider)
    pkcs11_del_provider(provider_id);

  return (k);
}
#endif /* WITH_PKCS11_KEYGEN */
#else /* ENABLE_PKCS11 */

#include <sys/types.h>
#include <stdarg.h>
#include <stdio.h>

#include "log.h"
#include "sshkey.h"

int
pkcs11_init(int interactive)
{
  error("%s: dlopen() not supported", __func__);
  return (-1);
}

int
pkcs11_add_provider(char *provider_id, char *pin, struct sshkey ***keyp,
    char ***labelsp)
{
  error("%s: dlopen() not supported", __func__);
  return (-1);
}

void
pkcs11_terminate(void)
{
  error("%s: dlopen() not supported", __func__);
}
#endif /* ENABLE_PKCS11 */

Coverage Report

Created: 2025-07-01 07:01