text: /* $OpenBSD: ssh-pkcs11.c,v 1.22 2016/02/12 00:20:30 djm Exp $ */
  /*
   * Copyright (c) 2010 Markus Friedl.  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
  
  #include <sys/types.h>
  #ifdef HAVE_SYS_TIME_H
  # include <sys/time.h>
  #endif
  #include <stdarg.h>
  #include <stdio.h>
  
  #include <string.h>
  #include <dlfcn.h>
  
  #include "openbsd-compat/sys-queue.h"
  
  #include <openssl/x509.h>
  
  #define CRYPTOKI_COMPAT
  #include "pkcs11.h"
  
  #include "log.h"
  #include "misc.h"
  #include "sshkey.h"
  #include "ssh-pkcs11.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;
  	int			(*orig_finish)(RSA *rsa);
  	RSA_METHOD		rsa_method;
  	char			*keyid;
  	int			keyid_len;
  };
  
  int pkcs11_interactive = 0;
  
  int
  pkcs11_init(int interactive)
  {
  	pkcs11_interactive = interactive;
  	TAILQ_INIT(&pkcs11_providers);
  	return (0);
  }
  
  /*
   * finalize a provider shared libarary, it's no longer usable.
   * however, there might still be keys referencing this provider,
   * so the actuall 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("pkcs11_provider_finalize: %p refcount %d valid %d",
  	    p, 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("pkcs11_provider_unref: %p refcount %d", p, p->refcount);
  	if (--p->refcount <= 0) {
  		if (p->valid)
  			error("pkcs11_provider_unref: %p still valid", p);
  		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 %p %s", p, 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);
  }
  
  /* openssl callback for freeing an RSA key */
  static int
  pkcs11_rsa_finish(RSA *rsa)
  {
  	struct pkcs11_key	*k11;
  	int rv = -1;
  
  	if ((k11 = RSA_get_app_data(rsa)) != NULL) {
  		if (k11->orig_finish)
  			rv = k11->orig_finish(rsa);
  		if (k11->provider)
  			pkcs11_provider_unref(k11->provider);
  		free(k11->keyid);
  		free(k11);
  	}
  	return (rv);
  }
  
  /* 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);
  }
  
  /* 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_OBJECT_HANDLE	obj;
  	CK_ULONG		tlen = 0;
  	CK_RV			rv;
  	CK_OBJECT_CLASS	private_key_class = CKO_PRIVATE_KEY;
  	CK_BBOOL		true_val = CK_TRUE;
  	CK_MECHANISM		mech = {
  		CKM_RSA_PKCS, NULL_PTR, 0
  	};
  	CK_ATTRIBUTE		key_filter[] = {
  		{CKA_CLASS, NULL, sizeof(private_key_class) },
  		{CKA_ID, NULL, 0},
  		{CKA_SIGN, NULL, sizeof(true_val) }
  	};
  	char			*pin = NULL, prompt[1024];
  	int			rval = -1;
  
  	key_filter[0].pValue = &private_key_class;
  	key_filter[2].pValue = &true_val;
  
  	if ((k11 = RSA_get_app_data(rsa)) == NULL) {
  		error("RSA_get_app_data failed for rsa %p", rsa);
  		return (-1);
  	}
  	if (!k11->provider || !k11->provider->valid) {
  		error("no pkcs11 (valid) provider for rsa %p", rsa);
  		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_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);
  			pin = read_passphrase(prompt, RP_ALLOW_EOF);
  			if (pin == NULL)
  				return (-1);	/* bail out */
  		}
  		rv = f->C_Login(si->session, CKU_USER, (u_char *)pin,
  		    (pin != NULL) ? strlen(pin) : 0);
  		if (pin != NULL) {
  			explicit_bzero(pin, strlen(pin));
  			free(pin);
  		}
  		if (rv != CKR_OK && rv != CKR_USER_ALREADY_LOGGED_IN) {
  			error("C_Login failed: %lu", rv);
  			return (-1);
  		}
  		si->logged_in = 1;
  	}
  	key_filter[1].pValue = k11->keyid;
  	key_filter[1].ulValueLen = k11->keyid_len;
  	/* 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");
  	} else if ((rv = f->C_SignInit(si->session, &mech, obj)) != CKR_OK) {
  		error("C_SignInit failed: %lu", rv);
  	} else {
  		/* XXX handle CKR_BUFFER_TOO_SMALL */
  		tlen = RSA_size(rsa);
  		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);
  }
  
  /* 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;
  	const RSA_METHOD	*def = RSA_get_default_method();
  
  	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);
  	}
  	k11->orig_finish = def->finish;
  	memcpy(&k11->rsa_method, def, sizeof(k11->rsa_method));
  	k11->rsa_method.name = "pkcs11";
  	k11->rsa_method.rsa_priv_enc = pkcs11_rsa_private_encrypt;
  	k11->rsa_method.rsa_priv_dec = pkcs11_rsa_private_decrypt;
  	k11->rsa_method.finish = pkcs11_rsa_finish;
  	RSA_set_method(rsa, &k11->rsa_method);
  	RSA_set_app_data(rsa, k11);
  	return (0);
  }
  
  /* remove trailing spaces */
  static void
  rmspace(u_char *buf, size_t len)
  {
  	size_t i;
  
  	if (!len)
  		return;
  	for (i = len - 1;  i > 0; i--)
  		if (i == len - 1 || buf[i] == ' ')
  			buf[i] = '\0';
  		else
  			break;
  }
  
  /*
   * 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_RV			rv;
  	CK_FUNCTION_LIST	*f;
  	CK_SESSION_HANDLE	session;
  	int			login_required;
  
  	f = p->function_list;
  	login_required = p->slotinfo[slotidx].token.flags & CKF_LOGIN_REQUIRED;
  	if (pin && login_required && !strlen(pin)) {
  		error("pin required");
  		return (-1);
  	}
  	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) {
  		rv = f->C_Login(session, CKU_USER,
  		    (u_char *)pin, strlen(pin));
  		if (rv != CKR_OK && rv != CKR_USER_ALREADY_LOGGED_IN) {
  			error("C_Login failed: %lu", rv);
  			if ((rv = f->C_CloseSession(session)) != CKR_OK)
  				error("C_CloseSession failed: %lu", rv);
  			return (-1);
  		}
  		p->slotinfo[slotidx].logged_in = 1;
  	}
  	p->slotinfo[slotidx].session = session;
  	return (0);
  }
  
  /*
   * 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_filter(struct pkcs11_provider *, CK_ULONG,
      CK_ATTRIBUTE [], CK_ATTRIBUTE [3], struct sshkey ***, int *)
  	__attribute__((__bounded__(__minbytes__,4, 3 * sizeof(CK_ATTRIBUTE))));
  
  static int
  pkcs11_fetch_keys(struct pkcs11_provider *p, CK_ULONG slotidx,
      struct sshkey ***keysp, int *nkeys)
  {
  	CK_OBJECT_CLASS	pubkey_class = CKO_PUBLIC_KEY;
  	CK_OBJECT_CLASS	cert_class = CKO_CERTIFICATE;
  	CK_ATTRIBUTE		pubkey_filter[] = {
  		{ CKA_CLASS, NULL, sizeof(pubkey_class) }
  	};
  	CK_ATTRIBUTE		cert_filter[] = {
  		{ CKA_CLASS, NULL, sizeof(cert_class) }
  	};
  	CK_ATTRIBUTE		pubkey_attribs[] = {
  		{ CKA_ID, NULL, 0 },
  		{ CKA_MODULUS, NULL, 0 },
  		{ CKA_PUBLIC_EXPONENT, NULL, 0 }
  	};
  	CK_ATTRIBUTE		cert_attribs[] = {
  		{ CKA_ID, NULL, 0 },
  		{ CKA_SUBJECT, NULL, 0 },
  		{ CKA_VALUE, NULL, 0 }
  	};
  	pubkey_filter[0].pValue = &pubkey_class;
  	cert_filter[0].pValue = &cert_class;
  
  	if (pkcs11_fetch_keys_filter(p, slotidx, pubkey_filter, pubkey_attribs,
  	    keysp, nkeys) < 0 ||
  	    pkcs11_fetch_keys_filter(p, slotidx, cert_filter, cert_attribs,
  	    keysp, nkeys) < 0)
  		return (-1);
  	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);
  }
  
  static int
  pkcs11_fetch_keys_filter(struct pkcs11_provider *p, CK_ULONG slotidx,
      CK_ATTRIBUTE filter[], CK_ATTRIBUTE attribs[3],
      struct sshkey ***keysp, int *nkeys)
  {
  	struct sshkey		*key;
  	RSA			*rsa;
  	X509 			*x509;
  	EVP_PKEY		*evp;
  	int			i;
  	const u_char		*cp;
  	CK_RV			rv;
  	CK_OBJECT_HANDLE	obj;
  	CK_ULONG		nfound;
  	CK_SESSION_HANDLE	session;
  	CK_FUNCTION_LIST	*f;
  
  	f = p->function_list;
  	session = p->slotinfo[slotidx].session;
  	/* setup a filter the looks for public keys */
  	if ((rv = f->C_FindObjectsInit(session, filter, 1)) != CKR_OK) {
  		error("C_FindObjectsInit failed: %lu", rv);
  		return (-1);
  	}
  	while (1) {
  		/* XXX 3 attributes in attribs[] */
  		for (i = 0; i < 3; i++) {
  			attribs[i].pValue = NULL;
  			attribs[i].ulValueLen = 0;
  		}
  		if ((rv = f->C_FindObjects(session, &obj, 1, &nfound)) != CKR_OK
  		    || nfound == 0)
  			break;
  		/* found a key, so figure out size of the attributes */
  		if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3))
  		    != CKR_OK) {
  			error("C_GetAttributeValue failed: %lu", rv);
  			continue;
  		}
  		/*
  		 * 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 (attribs[1].ulValueLen == 0 ||
  		    attribs[2].ulValueLen == 0) {
  			continue;
  		}
  		/* allocate buffers for attributes */
  		for (i = 0; i < 3; i++) {
  			if (attribs[i].ulValueLen > 0) {
  				attribs[i].pValue = xmalloc(
  				    attribs[i].ulValueLen);
  			}
  		}
  
  		/*
  		 * retrieve ID, modulus and public exponent of RSA key,
  		 * or ID, subject and value for certificates.
  		 */
  		rsa = NULL;
  		if ((rv = f->C_GetAttributeValue(session, obj, attribs, 3))
  		    != CKR_OK) {
  			error("C_GetAttributeValue failed: %lu", rv);
  		} else if (attribs[1].type == CKA_MODULUS ) {
  			if ((rsa = RSA_new()) == NULL) {
  				error("RSA_new failed");
  			} else {
  				rsa->n = BN_bin2bn(attribs[1].pValue,
  				    attribs[1].ulValueLen, NULL);
  				rsa->e = BN_bin2bn(attribs[2].pValue,
  				    attribs[2].ulValueLen, NULL);
  			}
  		} else {
  			cp = attribs[2].pValue;
  			if ((x509 = X509_new()) == NULL) {
  				error("X509_new failed");
  			} else if (d2i_X509(&x509, &cp, attribs[2].ulValueLen)
  			    == NULL) {
  				error("d2i_X509 failed");
  			} else if ((evp = X509_get_pubkey(x509)) == NULL ||
  			    evp->type != EVP_PKEY_RSA ||
  			    evp->pkey.rsa == NULL) {
  				debug("X509_get_pubkey failed or no rsa");
  			} else if ((rsa = RSAPublicKey_dup(evp->pkey.rsa))
  			    == NULL) {
  				error("RSAPublicKey_dup");
  			}
  			if (x509)
  				X509_free(x509);
  		}
  		if (rsa && rsa->n && rsa->e &&
  		    pkcs11_rsa_wrap(p, slotidx, &attribs[0], rsa) == 0) {
  			key = sshkey_new(KEY_UNSPEC);
  			key->rsa = rsa;
  			key->type = KEY_RSA;
  			key->flags |= SSHKEY_FLAG_EXT;
  			if (pkcs11_key_included(keysp, nkeys, key)) {
  				sshkey_free(key);
  			} else {
  				/* expand key array and add key */
  				*keysp = xreallocarray(*keysp, *nkeys + 1,
  				    sizeof(struct sshkey *));
  				(*keysp)[*nkeys] = key;
  				*nkeys = *nkeys + 1;
  				debug("have %d keys", *nkeys);
  			}
  		} else if (rsa) {
  			RSA_free(rsa);
  		}
  		for (i = 0; i < 3; i++)
  			free(attribs[i].pValue);
  	}
  	if ((rv = f->C_FindObjectsFinal(session)) != CKR_OK)
  		error("C_FindObjectsFinal failed: %lu", rv);
  	return (0);
  }
  
  /* register a new provider, fails if provider already exists */
  int
  pkcs11_add_provider(char *provider_id, char *pin, struct sshkey ***keyp)
  {
  	int nkeys, need_finalize = 0;
  	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;
  
  	*keyp = NULL;
  	if (pkcs11_provider_lookup(provider_id) != NULL) {
  		error("provider already registered: %s", provider_id);
  		goto fail;
  	}
  	/* open shared pkcs11-libarary */
  	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) {
  		error("dlsym(C_GetFunctionList) failed: %s", dlerror());
  		goto fail;
  	}
  	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 failed: %lu", rv);
  		goto fail;
  	}
  	p->function_list = f;
  	if ((rv = f->C_Initialize(NULL)) != CKR_OK) {
  		error("C_Initialize failed: %lu", rv);
  		goto fail;
  	}
  	need_finalize = 1;
  	if ((rv = f->C_GetInfo(&p->info)) != CKR_OK) {
  		error("C_GetInfo failed: %lu", rv);
  		goto fail;
  	}
  	rmspace(p->info.manufacturerID, sizeof(p->info.manufacturerID));
  	rmspace(p->info.libraryDescription, sizeof(p->info.libraryDescription));
  	debug("manufacturerID <%s> cryptokiVersion %d.%d"
  	    " libraryDescription <%s> libraryVersion %d.%d",
  	    p->info.manufacturerID,
  	    p->info.cryptokiVersion.major,
  	    p->info.cryptokiVersion.minor,
  	    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) {
  		error("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 failed: %lu", 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 failed: %lu", rv);
  			continue;
  		}
  		if ((token->flags & CKF_TOKEN_INITIALIZED) == 0) {
  			debug2("%s: ignoring uninitialised token in slot %lu",
  			    __func__, (unsigned long)i);
  			continue;
  		}
  		rmspace(token->label, sizeof(token->label));
  		rmspace(token->manufacturerID, sizeof(token->manufacturerID));
  		rmspace(token->model, sizeof(token->model));
  		rmspace(token->serialNumber, sizeof(token->serialNumber));
  		debug("label <%s> manufacturerID <%s> model <%s> serial <%s>"
  		    " flags 0x%lx",
  		    token->label, token->manufacturerID, token->model,
  		    token->serialNumber, token->flags);
  		/* open session, login with pin and retrieve public keys */
  		if (pkcs11_open_session(p, i, pin) == 0)
  			pkcs11_fetch_keys(p, i, keyp, &nkeys);
  	}
  	if (nkeys > 0) {
  		TAILQ_INSERT_TAIL(&pkcs11_providers, p, next);
  		p->refcount++;	/* add to provider list */
  		return (nkeys);
  	}
  	error("no keys");
  	/* don't add the provider, since it does not have any keys */
  fail:
  	if (need_finalize && (rv = f->C_Finalize(NULL)) != CKR_OK)
  		error("C_Finalize failed: %lu", rv);
  	if (p) {
  		free(p->slotlist);
  		free(p->slotinfo);
  		free(p);
  	}
  	if (handle)
  		dlclose(handle);
  	return (-1);
  }
  
  #else
  
  int
  pkcs11_init(int interactive)
  {
  	return (0);
  }
  
  void
  pkcs11_terminate(void)
  {
  	return;
  }
  
  #endif /* ENABLE_PKCS11 */
  