ssh-pkcs11-helper.c - third_party/openssh-portable - Git at Google

 /* $OpenBSD: ssh-pkcs11-helper.c,v 1.14 2018/01/08 15:18:46 markus 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"

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

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

 #include <stdarg.h>
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>

 #include "xmalloc.h"
 #include "sshbuf.h"
 #include "log.h"
 #include "misc.h"
 #include "sshkey.h"
 #include "authfd.h"
 #include "ssh-pkcs11.h"
 #include "ssherr.h"

 #ifdef ENABLE_PKCS11

 /* borrows code from sftp-server and ssh-agent */

 struct pkcs11_keyinfo {
 	struct sshkey	*key;
 	char		*providername;
 	TAILQ_ENTRY(pkcs11_keyinfo) next;
 };

 TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;

 #define MAX_MSG_LENGTH		10240 /*XXX*/

 /* input and output queue */
 struct sshbuf *iqueue;
 struct sshbuf *oqueue;

 static void
 add_key(struct sshkey *k, char *name)
 {
 	struct pkcs11_keyinfo *ki;

 	ki = xcalloc(1, sizeof(*ki));
 	ki->providername = xstrdup(name);
 	ki->key = k;
 	TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
 }

 static void
 del_keys_by_name(char *name)
 {
 	struct pkcs11_keyinfo *ki, *nxt;

 	for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
 		nxt = TAILQ_NEXT(ki, next);
 		if (!strcmp(ki->providername, name)) {
 			TAILQ_REMOVE(&pkcs11_keylist, ki, next);
 			free(ki->providername);
 			sshkey_free(ki->key);
 			free(ki);
 		}
 	}
 }

 /* lookup matching 'private' key */
 static struct sshkey *
 lookup_key(struct sshkey *k)
 {
 	struct pkcs11_keyinfo *ki;

 	TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
 		debug("check %p %s", ki, ki->providername);
 		if (sshkey_equal(k, ki->key))
 			return (ki->key);
 	}
 	return (NULL);
 }

 static void
 send_msg(struct sshbuf *m)
 {
 	int r;

 	if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 }

 static void
 process_add(void)
 {
 	char *name, *pin;
 	struct sshkey **keys;
 	int r, i, nkeys;
 	u_char *blob;
 	size_t blen;
 	struct sshbuf *msg;

 	if ((msg = sshbuf_new()) == NULL)
 		fatal("%s: sshbuf_new failed", __func__);
 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
 	    (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
 		if ((r = sshbuf_put_u8(msg,
 		    SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
 		    (r = sshbuf_put_u32(msg, nkeys)) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 		for (i = 0; i < nkeys; i++) {
 			if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
 				debug("%s: sshkey_to_blob: %s",
 				    __func__, ssh_err(r));
 				continue;
 			}
 			if ((r = sshbuf_put_string(msg, blob, blen)) != 0 ||
 			    (r = sshbuf_put_cstring(msg, name)) != 0)
 				fatal("%s: buffer error: %s",
 				    __func__, ssh_err(r));
 			free(blob);
 			add_key(keys[i], name);
 		}
 		free(keys);
 	} else {
 		if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
 	free(pin);
 	free(name);
 	send_msg(msg);
 	sshbuf_free(msg);
 }

 static void
 process_del(void)
 {
 	char *name, *pin;
 	struct sshbuf *msg;
 	int r;

 	if ((msg = sshbuf_new()) == NULL)
 		fatal("%s: sshbuf_new failed", __func__);
 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
 	    (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	del_keys_by_name(name);
 	if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
 	    SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	free(pin);
 	free(name);
 	send_msg(msg);
 	sshbuf_free(msg);
 }

 static void
 process_sign(void)
 {
 	u_char *blob, *data, *signature = NULL;
 	size_t blen, dlen, slen = 0;
 	int r, ok = -1;
 	struct sshkey *key, *found;
 	struct sshbuf *msg;

 	/* XXX support SHA2 signature flags */
 	if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
 	    (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
 	    (r = sshbuf_get_u32(iqueue, NULL)) != 0)
 		fatal("%s: buffer error: %s", __func__, ssh_err(r));

 	if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
 		error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
 	else {
 		if ((found = lookup_key(key)) != NULL) {
 #ifdef WITH_OPENSSL
 			int ret;

 			slen = RSA_size(key->rsa);
 			signature = xmalloc(slen);
 			if ((ret = RSA_private_encrypt(dlen, data, signature,
 			    found->rsa, RSA_PKCS1_PADDING)) != -1) {
 				slen = ret;
 				ok = 0;
 			}
 #endif /* WITH_OPENSSL */
 		}
 		sshkey_free(key);
 	}
 	if ((msg = sshbuf_new()) == NULL)
 		fatal("%s: sshbuf_new failed", __func__);
 	if (ok == 0) {
 		if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
 		    (r = sshbuf_put_string(msg, signature, slen)) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	} else {
 		if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
 	free(data);
 	free(blob);
 	free(signature);
 	send_msg(msg);
 	sshbuf_free(msg);
 }

 static void
 process(void)
 {
 	u_int msg_len;
 	u_int buf_len;
 	u_int consumed;
 	u_char type;
 	const u_char *cp;
 	int r;

 	buf_len = sshbuf_len(iqueue);
 	if (buf_len < 5)
 		return;		/* Incomplete message. */
 	cp = sshbuf_ptr(iqueue);
 	msg_len = get_u32(cp);
 	if (msg_len > MAX_MSG_LENGTH) {
 		error("bad message len %d", msg_len);
 		cleanup_exit(11);
 	}
 	if (buf_len < msg_len + 4)
 		return;
 	if ((r = sshbuf_consume(iqueue, 4)) != 0 ||
 	    (r = sshbuf_get_u8(iqueue, &type)) != 0)
 		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	buf_len -= 4;
 	switch (type) {
 	case SSH_AGENTC_ADD_SMARTCARD_KEY:
 		debug("process_add");
 		process_add();
 		break;
 	case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
 		debug("process_del");
 		process_del();
 		break;
 	case SSH2_AGENTC_SIGN_REQUEST:
 		debug("process_sign");
 		process_sign();
 		break;
 	default:
 		error("Unknown message %d", type);
 		break;
 	}
 	/* discard the remaining bytes from the current packet */
 	if (buf_len < sshbuf_len(iqueue)) {
 		error("iqueue grew unexpectedly");
 		cleanup_exit(255);
 	}
 	consumed = buf_len - sshbuf_len(iqueue);
 	if (msg_len < consumed) {
 		error("msg_len %d < consumed %d", msg_len, consumed);
 		cleanup_exit(255);
 	}
 	if (msg_len > consumed) {
 		if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
 }

 void
 cleanup_exit(int i)
 {
 	/* XXX */
 	_exit(i);
 }

 int
 main(int argc, char **argv)
 {
 	fd_set *rset, *wset;
 	int r, in, out, max, log_stderr = 0;
 	ssize_t len, olen, set_size;
 	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
 	LogLevel log_level = SYSLOG_LEVEL_ERROR;
 	char buf[4*4096];

 	extern char *__progname;

 	ssh_malloc_init();	/* must be called before any mallocs */
 	TAILQ_INIT(&pkcs11_keylist);
 	pkcs11_init(0);

 	seed_rng();
 	__progname = ssh_get_progname(argv[0]);

 	log_init(__progname, log_level, log_facility, log_stderr);

 	in = STDIN_FILENO;
 	out = STDOUT_FILENO;

 	max = 0;
 	if (in > max)
 		max = in;
 	if (out > max)
 		max = out;

 	if ((iqueue = sshbuf_new()) == NULL)
 		fatal("%s: sshbuf_new failed", __func__);
 	if ((oqueue = sshbuf_new()) == NULL)
 		fatal("%s: sshbuf_new failed", __func__);

 	set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
 	rset = xmalloc(set_size);
 	wset = xmalloc(set_size);

 	for (;;) {
 		memset(rset, 0, set_size);
 		memset(wset, 0, set_size);

 		/*
 		 * Ensure that we can read a full buffer and handle
 		 * the worst-case length packet it can generate,
 		 * otherwise apply backpressure by stopping reads.
 		 */
 		if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
 		    (r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
 			FD_SET(in, rset);
 		else if (r != SSH_ERR_NO_BUFFER_SPACE)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));

 		olen = sshbuf_len(oqueue);
 		if (olen > 0)
 			FD_SET(out, wset);

 #ifdef __Fuchsia___
 		if (fuchsia_select(max+1, rset, wset, NULL) < 0) {
 #else
 		if (select(max+1, rset, wset, NULL, NULL) < 0) {
 #endif
 			if (errno == EINTR)
 				continue;
 			error("select: %s", strerror(errno));
 			cleanup_exit(2);
 		}

 		/* copy stdin to iqueue */
 		if (FD_ISSET(in, rset)) {
 			len = read(in, buf, sizeof buf);
 			if (len == 0) {
 				debug("read eof");
 				cleanup_exit(0);
 			} else if (len < 0) {
 				error("read: %s", strerror(errno));
 				cleanup_exit(1);
 			} else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
 				fatal("%s: buffer error: %s",
 				    __func__, ssh_err(r));
 			}
 		}
 		/* send oqueue to stdout */
 		if (FD_ISSET(out, wset)) {
 			len = write(out, sshbuf_ptr(oqueue), olen);
 			if (len < 0) {
 				error("write: %s", strerror(errno));
 				cleanup_exit(1);
 			} else if ((r = sshbuf_consume(oqueue, len)) != 0) {
 				fatal("%s: buffer error: %s",
 				    __func__, ssh_err(r));
 			}
 		}

 		/*
 		 * Process requests from client if we can fit the results
 		 * into the output buffer, otherwise stop processing input
 		 * and let the output queue drain.
 		 */
 		if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
 			process();
 		else if (r != SSH_ERR_NO_BUFFER_SPACE)
 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
 }
 #else /* ENABLE_PKCS11 */
 int
 main(int argc, char **argv)
 {
 	extern char *__progname;

 	__progname = ssh_get_progname(argv[0]);
 	log_init(__progname, SYSLOG_LEVEL_ERROR, SYSLOG_FACILITY_AUTH, 0);
 	fatal("PKCS#11 support disabled at compile time");
 }
 #endif /* ENABLE_PKCS11 */
	/* $OpenBSD: ssh-pkcs11-helper.c,v 1.14 2018/01/08 15:18:46 markus 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"

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

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

	#include <stdarg.h>
	#include <string.h>
	#include <unistd.h>
	#include <errno.h>

	#include "xmalloc.h"
	#include "sshbuf.h"
	#include "log.h"
	#include "misc.h"
	#include "sshkey.h"
	#include "authfd.h"
	#include "ssh-pkcs11.h"
	#include "ssherr.h"

	#ifdef ENABLE_PKCS11

	/* borrows code from sftp-server and ssh-agent */

	struct pkcs11_keyinfo {
	struct sshkey *key;
	char *providername;
	TAILQ_ENTRY(pkcs11_keyinfo) next;
	};

	TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;

	#define MAX_MSG_LENGTH 10240 /XXX/

	/* input and output queue */
	struct sshbuf *iqueue;
	struct sshbuf *oqueue;

	static void
	add_key(struct sshkey k, char name)
	{
	struct pkcs11_keyinfo *ki;

	ki = xcalloc(1, sizeof(*ki));
	ki->providername = xstrdup(name);
	ki->key = k;
	TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
	}

	static void
	del_keys_by_name(char *name)
	{
	struct pkcs11_keyinfo ki, nxt;

	for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
	nxt = TAILQ_NEXT(ki, next);
	if (!strcmp(ki->providername, name)) {
	TAILQ_REMOVE(&pkcs11_keylist, ki, next);
	free(ki->providername);
	sshkey_free(ki->key);
	free(ki);
	}
	}
	}

	/* lookup matching 'private' key */
	static struct sshkey *
	lookup_key(struct sshkey *k)
	{
	struct pkcs11_keyinfo *ki;

	TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
	debug("check %p %s", ki, ki->providername);
	if (sshkey_equal(k, ki->key))
	return (ki->key);
	}
	return (NULL);
	}

	static void
	send_msg(struct sshbuf *m)
	{
	int r;

	if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}

	static void
	process_add(void)
	{
	char name, pin;
	struct sshkey **keys;
	int r, i, nkeys;
	u_char *blob;
	size_t blen;
	struct sshbuf *msg;

	if ((msg = sshbuf_new()) == NULL)
	fatal("%s: sshbuf_new failed", __func__);
	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 \|\|
	(r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
	if ((r = sshbuf_put_u8(msg,
	SSH2_AGENT_IDENTITIES_ANSWER)) != 0 \|\|
	(r = sshbuf_put_u32(msg, nkeys)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	for (i = 0; i < nkeys; i++) {
	if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
	debug("%s: sshkey_to_blob: %s",
	__func__, ssh_err(r));
	continue;
	}
	if ((r = sshbuf_put_string(msg, blob, blen)) != 0 \|\|
	(r = sshbuf_put_cstring(msg, name)) != 0)
	fatal("%s: buffer error: %s",
	__func__, ssh_err(r));
	free(blob);
	add_key(keys[i], name);
	}
	free(keys);
	} else {
	if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}
	free(pin);
	free(name);
	send_msg(msg);
	sshbuf_free(msg);
	}

	static void
	process_del(void)
	{
	char name, pin;
	struct sshbuf *msg;
	int r;

	if ((msg = sshbuf_new()) == NULL)
	fatal("%s: sshbuf_new failed", __func__);
	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 \|\|
	(r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	del_keys_by_name(name);
	if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
	SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	free(pin);
	free(name);
	send_msg(msg);
	sshbuf_free(msg);
	}

	static void
	process_sign(void)
	{
	u_char blob, data, *signature = NULL;
	size_t blen, dlen, slen = 0;
	int r, ok = -1;
	struct sshkey key, found;
	struct sshbuf *msg;

	/* XXX support SHA2 signature flags */
	if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 \|\|
	(r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 \|\|
	(r = sshbuf_get_u32(iqueue, NULL)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));

	if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
	error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
	else {
	if ((found = lookup_key(key)) != NULL) {
	#ifdef WITH_OPENSSL
	int ret;

	slen = RSA_size(key->rsa);
	signature = xmalloc(slen);
	if ((ret = RSA_private_encrypt(dlen, data, signature,
	found->rsa, RSA_PKCS1_PADDING)) != -1) {
	slen = ret;
	ok = 0;
	}
	#endif /* WITH_OPENSSL */
	}
	sshkey_free(key);
	}
	if ((msg = sshbuf_new()) == NULL)
	fatal("%s: sshbuf_new failed", __func__);
	if (ok == 0) {
	if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 \|\|
	(r = sshbuf_put_string(msg, signature, slen)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	} else {
	if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}
	free(data);
	free(blob);
	free(signature);
	send_msg(msg);
	sshbuf_free(msg);
	}

	static void
	process(void)
	{
	u_int msg_len;
	u_int buf_len;
	u_int consumed;
	u_char type;
	const u_char *cp;
	int r;

	buf_len = sshbuf_len(iqueue);
	if (buf_len < 5)
	return; /* Incomplete message. */
	cp = sshbuf_ptr(iqueue);
	msg_len = get_u32(cp);
	if (msg_len > MAX_MSG_LENGTH) {
	error("bad message len %d", msg_len);
	cleanup_exit(11);
	}
	if (buf_len < msg_len + 4)
	return;
	if ((r = sshbuf_consume(iqueue, 4)) != 0 \|\|
	(r = sshbuf_get_u8(iqueue, &type)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	buf_len -= 4;
	switch (type) {
	case SSH_AGENTC_ADD_SMARTCARD_KEY:
	debug("process_add");
	process_add();
	break;
	case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
	debug("process_del");
	process_del();
	break;
	case SSH2_AGENTC_SIGN_REQUEST:
	debug("process_sign");
	process_sign();
	break;
	default:
	error("Unknown message %d", type);
	break;
	}
	/* discard the remaining bytes from the current packet */
	if (buf_len < sshbuf_len(iqueue)) {
	error("iqueue grew unexpectedly");
	cleanup_exit(255);
	}
	consumed = buf_len - sshbuf_len(iqueue);
	if (msg_len < consumed) {
	error("msg_len %d < consumed %d", msg_len, consumed);
	cleanup_exit(255);
	}
	if (msg_len > consumed) {
	if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}
	}

	void
	cleanup_exit(int i)
	{
	/* XXX */
	_exit(i);
	}

	int
	main(int argc, char **argv)
	{
	fd_set rset, wset;
	int r, in, out, max, log_stderr = 0;
	ssize_t len, olen, set_size;
	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
	LogLevel log_level = SYSLOG_LEVEL_ERROR;
	char buf[4*4096];

	extern char *__progname;

	ssh_malloc_init(); /* must be called before any mallocs */
	TAILQ_INIT(&pkcs11_keylist);
	pkcs11_init(0);

	seed_rng();
	__progname = ssh_get_progname(argv[0]);

	log_init(__progname, log_level, log_facility, log_stderr);

	in = STDIN_FILENO;
	out = STDOUT_FILENO;

	max = 0;
	if (in > max)
	max = in;
	if (out > max)
	max = out;

	if ((iqueue = sshbuf_new()) == NULL)
	fatal("%s: sshbuf_new failed", __func__);
	if ((oqueue = sshbuf_new()) == NULL)
	fatal("%s: sshbuf_new failed", __func__);

	set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
	rset = xmalloc(set_size);
	wset = xmalloc(set_size);

	for (;;) {
	memset(rset, 0, set_size);
	memset(wset, 0, set_size);

	/*
	* Ensure that we can read a full buffer and handle
	* the worst-case length packet it can generate,
	* otherwise apply backpressure by stopping reads.
	*/
	if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
	(r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
	FD_SET(in, rset);
	else if (r != SSH_ERR_NO_BUFFER_SPACE)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));

	olen = sshbuf_len(oqueue);
	if (olen > 0)
	FD_SET(out, wset);

	#ifdef __Fuchsia___
	if (fuchsia_select(max+1, rset, wset, NULL) < 0) {
	#else
	if (select(max+1, rset, wset, NULL, NULL) < 0) {
	#endif
	if (errno == EINTR)
	continue;
	error("select: %s", strerror(errno));
	cleanup_exit(2);
	}

	/* copy stdin to iqueue */
	if (FD_ISSET(in, rset)) {
	len = read(in, buf, sizeof buf);
	if (len == 0) {
	debug("read eof");
	cleanup_exit(0);
	} else if (len < 0) {
	error("read: %s", strerror(errno));
	cleanup_exit(1);
	} else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
	fatal("%s: buffer error: %s",
	__func__, ssh_err(r));
	}
	}
	/* send oqueue to stdout */
	if (FD_ISSET(out, wset)) {
	len = write(out, sshbuf_ptr(oqueue), olen);
	if (len < 0) {
	error("write: %s", strerror(errno));
	cleanup_exit(1);
	} else if ((r = sshbuf_consume(oqueue, len)) != 0) {
	fatal("%s: buffer error: %s",
	__func__, ssh_err(r));
	}
	}

	/*
	* Process requests from client if we can fit the results
	* into the output buffer, otherwise stop processing input
	* and let the output queue drain.
	*/
	if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
	process();
	else if (r != SSH_ERR_NO_BUFFER_SPACE)
	fatal("%s: buffer error: %s", __func__, ssh_err(r));
	}
	}
	#else /* ENABLE_PKCS11 */
	int
	main(int argc, char **argv)
	{
	extern char *__progname;

	__progname = ssh_get_progname(argv[0]);
	log_init(__progname, SYSLOG_LEVEL_ERROR, SYSLOG_FACILITY_AUTH, 0);
	fatal("PKCS#11 support disabled at compile time");
	}
	#endif /* ENABLE_PKCS11 */