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IABSD.fr/src/usr.bin/ssh/ssh-pkcs11.c

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  • Author : djm
    Date : 2021-11-18 21:11:01
    Hash : a9f89e4d
    Message : avoid xmalloc(0) for PKCS#11 keyid for ECDSA keys (we already did this for RSA keys). Avoids fatal errors for PKCS#11 libraries that return empty keyid, e.g. Microchip ATECC608B "cryptoauthlib"; bz#3364

  • usr.bin/ssh/ssh-pkcs11.c
  • /* $OpenBSD: ssh-pkcs11.c,v 1.55 2021/11/18 21:11:01 djm 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 <sys/types.h>
    #include <sys/queue.h>
    #include <stdarg.h>
    #include <stdio.h>
    
    #include <ctype.h>
    #include <string.h>
    #include <dlfcn.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;
    
    #ifdef HAVE_DLOPEN
    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
    
    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;
    #ifdef HAVE_DLOPEN
    	dlclose(p->handle);
    #endif
    }
    
    /*
     * 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);
    }
    
    #ifdef HAVE_DLOPEN
    static RSA_METHOD *rsa_method;
    static int rsa_idx = 0;
    static EC_KEY_METHOD *ec_key_method;
    static int ec_key_idx = 0;
    
    /* 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);
    	}
    
    	RSA_set_method(rsa, rsa_method);
    	RSA_set_ex_data(rsa, rsa_idx, k11);
    	return (0);
    }
    
    /* 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_key_method_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) {
    		ossl_error("d2i_ECDSA_SIG failed");
    		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("d2i_ECDSA_SIG 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);
    	}
    	EC_KEY_set_method(ec, ec_key_method);
    	EC_KEY_set_ex_data(ec, ec_key_idx, 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_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);
    }
    
    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;
    	}
    
    	key->ecdsa = ec;
    	key->ecdsa_nid = nid;
    	key->type = KEY_ECDSA;
    	key->flags |= SSHKEY_FLAG_EXT;
    	ec = NULL;	/* now owned by key */
    
    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);
    }
    
    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;
    	}
    
    	key->rsa = rsa;
    	key->type = KEY_RSA;
    	key->flags |= SSHKEY_FLAG_EXT;
    	rsa = NULL;	/* now owned by key */
    
    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;
    	EC_KEY			*ec = NULL;
    	struct sshkey		*key = NULL;
    	int			 i;
    	int			 nid;
    	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;
    		}
    
    		key->rsa = rsa;
    		key->type = KEY_RSA;
    		key->flags |= SSHKEY_FLAG_EXT;
    		rsa = NULL;	/* now owned by key */
    	} 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;
    		}
    
    		key->ecdsa = ec;
    		key->ecdsa_nid = nid;
    		key->type = KEY_ECDSA;
    		key->flags |= SSHKEY_FLAG_EXT;
    		ec = NULL;	/* now owned by key */
    	} 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);
    	EC_KEY_free(ec);
    	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;
    		case CKK_ECDSA:
    			key = pkcs11_fetch_ecdsa_pubkey(p, slotidx, &obj);
    			break;
    		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 */
    	};
    
    	*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
    pkcs11_decode_hex(const char *hex, unsigned char **dest, size_t *rlen)
    {
    	size_t	i, len;
    	char	ptr[3];
    
    	if (dest)
    		*dest = NULL;
    	if (rlen)
    		*rlen = 0;
    
    	if ((len = strlen(hex)) % 2)
    		return -1;
    	len /= 2;
    
    	*dest = xmalloc(len);
    
    	ptr[2] = '\0';
    	for (i = 0; i < len; i++) {
    		ptr[0] = hex[2 * i];
    		ptr[1] = hex[(2 * i) + 1];
    		if (!isxdigit(ptr[0]) || !isxdigit(ptr[1]))
    			return -1;
    		(*dest)[i] = (unsigned char)strtoul(ptr, NULL, 16);
    	}
    
    	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;
    	}
    	/* 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) {
    		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 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;
    	}
    	rmspace(p->info.manufacturerID, sizeof(p->info.manufacturerID));
    	rmspace(p->info.libraryDescription, sizeof(p->info.libraryDescription));
    	debug("provider %s: manufacturerID <%s> cryptokiVersion %d.%d"
    	    " libraryDescription <%s> libraryVersion %d.%d",
    	    provider_id,
    	    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) {
    		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;
    		}
    		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("provider %s slot %lu: label <%s> manufacturerID <%s> "
    		    "model <%s> serial <%s> flags 0x%lx",
    		    provider_id, (unsigned long)i,
    		    token->label, token->manufacturerID, token->model,
    		    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
    int
    pkcs11_add_provider(char *provider_id, char *pin, struct sshkey ***keyp,
        char ***labelsp)
    {
    	error("dlopen() not supported");
    	return (-1);
    }
    #endif /* HAVE_DLOPEN */