Exemplo n.º 1
0
/*
 * Child process.
 */
static void *
pam_child(struct pam_ctxt *ctxt)
{
	Buffer buffer;
	struct pam_conv pam_conv;
	pam_handle_t *pamh;
	int pam_err;

	pam_conv.conv = pam_child_conv;
	pam_conv.appdata_ptr = ctxt;
	buffer_init(&buffer);
	setproctitle("%s [pam]", ctxt->pam_user);
	pam_err = pam_start("sshd", ctxt->pam_user, &pam_conv, &pamh);
	if (pam_err != PAM_SUCCESS)
		goto auth_fail;
	pam_err = pam_authenticate(pamh, 0);
	if (pam_err != PAM_SUCCESS)
		goto auth_fail;
	pam_err = pam_acct_mgmt(pamh, 0);
	if (pam_err != PAM_SUCCESS)
		goto auth_fail;
	buffer_put_cstring(&buffer, "OK");
	ssh_msg_send(ctxt->pam_sock, PAM_SUCCESS, &buffer);
	buffer_free(&buffer);
	pam_end(pamh, pam_err);
	exit(0);
 auth_fail:
	buffer_put_cstring(&buffer, pam_strerror(pamh, pam_err));
	ssh_msg_send(ctxt->pam_sock, PAM_AUTH_ERR, &buffer);
	buffer_free(&buffer);
	pam_end(pamh, pam_err);
	exit(0);
}
Exemplo n.º 2
0
/*
 * Conversation function for child process.
 */
static int
pam_child_conv(int n,
	 const struct pam_message **msg,
	 struct pam_response **resp,
	 void *data)
{
	Buffer buffer;
	struct pam_ctxt *ctxt;
	int i;

	ctxt = data;
	if (n <= 0 || n > PAM_MAX_NUM_MSG)
		return (PAM_CONV_ERR);
	*resp = xmalloc(n * sizeof **resp);
	buffer_init(&buffer);
	for (i = 0; i < n; ++i) {
		resp[i]->resp_retcode = 0;
		resp[i]->resp = NULL;
		switch (msg[i]->msg_style) {
		case PAM_PROMPT_ECHO_OFF:
			buffer_put_cstring(&buffer, msg[i]->msg);
			ssh_msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
			ssh_msg_recv(ctxt->pam_sock, &buffer);
			if (buffer_get_char(&buffer) != PAM_AUTHTOK)
				goto fail;
			resp[i]->resp = buffer_get_string(&buffer, NULL);
			break;
		case PAM_PROMPT_ECHO_ON:
			buffer_put_cstring(&buffer, msg[i]->msg);
			ssh_msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
			ssh_msg_recv(ctxt->pam_sock, &buffer);
			if (buffer_get_char(&buffer) != PAM_AUTHTOK)
				goto fail;
			resp[i]->resp = buffer_get_string(&buffer, NULL);
			break;
		case PAM_ERROR_MSG:
			buffer_put_cstring(&buffer, msg[i]->msg);
			ssh_msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
			break;
		case PAM_TEXT_INFO:
			buffer_put_cstring(&buffer, msg[i]->msg);
			ssh_msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
			break;
		default:
			goto fail;
		}
		buffer_clear(&buffer);
	}
	buffer_free(&buffer);
	return (PAM_SUCCESS);
 fail:
	while (i)
		xfree(resp[--i]);
	xfree(*resp);
	*resp = NULL;
	buffer_free(&buffer);
	return (PAM_CONV_ERR);
}
Exemplo n.º 3
0
/* XXX - see also comment in auth-chall.c:verify_response */
static int
sshpam_respond(void *ctx, u_int num, char **resp)
{
	Buffer buffer;
	struct pam_ctxt *ctxt = ctx;

	debug2("PAM: %s entering, %u responses", __func__, num);
	switch (ctxt->pam_done) {
	case 1:
		sshpam_authenticated = 1;
		return (0);
	case 0:
		break;
	default:
		return (-1);
	}
	if (num != 1) {
		error("PAM: expected one response, got %u", num);
		return (-1);
	}
	buffer_init(&buffer);
	if (sshpam_authctxt->valid &&
	    (sshpam_authctxt->pw->pw_uid != 0 ||
	    options.permit_root_login == PERMIT_YES))
		buffer_put_cstring(&buffer, *resp);
	else
		buffer_put_cstring(&buffer, badpw);
	if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
		buffer_free(&buffer);
		return (-1);
	}
	buffer_free(&buffer);
	return (1);
}
Exemplo n.º 4
0
static int
pam_respond(void *ctx, u_int num, char **resp)
{
	Buffer buffer;
	struct pam_ctxt *ctxt = ctx;
	char *msg;

	debug2(__func__);
	switch (ctxt->pam_done) {
	case 1:
		return (0);	
	case 0:
		break;
	default:
		return (-1);
	}
	if (num != 1) {
		error("expected one response, got %u", num);
		return (-1);
	}
	buffer_init(&buffer);
	buffer_put_cstring(&buffer, *resp);
	ssh_msg_send(ctxt->pam_sock, PAM_AUTHTOK, &buffer);
	buffer_free(&buffer);
	return (1);
}
Exemplo n.º 5
0
/* XXX - see also comment in auth-chall.c:verify_response */
static int
sshpam_respond(void *ctx, u_int num, char **resp)
{
	struct sshbuf *buffer;
	struct pam_ctxt *ctxt = ctx;
	char *fake;
	int r;

	debug2("PAM: %s entering, %u responses", __func__, num);
	switch (ctxt->pam_done) {
	case 1:
		sshpam_authenticated = 1;
		return (0);
	case 0:
		break;
	default:
		return (-1);
	}
	if (num != 1) {
		error("PAM: expected one response, got %u", num);
		return (-1);
	}
	if ((buffer = sshbuf_new()) == NULL)
		fatal("%s: sshbuf_new failed", __func__);
	if (sshpam_authctxt->valid &&
	    (sshpam_authctxt->pw->pw_uid != 0 ||
	    options.permit_root_login == PERMIT_YES)) {
		if ((r = sshbuf_put_cstring(buffer, *resp)) != 0)
			fatal("%s: buffer error: %s", __func__, ssh_err(r));
	} else {
		fake = fake_password(*resp);
		if ((r = sshbuf_put_cstring(buffer, fake)) != 0)
			fatal("%s: buffer error: %s", __func__, ssh_err(r));
		free(fake);
	}
	if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, buffer) == -1) {
		sshbuf_free(buffer);
		return (-1);
	}
	sshbuf_free(buffer);
	return (1);
}
Exemplo n.º 6
0
static void
send_rexec_state(int fd, Buffer *conf)
{
	Buffer m;

	debug3("%s: entering fd = %d config len %d", __func__, fd,
	    buffer_len(conf));

	/*
	 * Protocol from reexec master to child:
	 *	string	configuration
	 *	u_int	ephemeral_key_follows
	 *	bignum	e		(only if ephemeral_key_follows == 1)
	 *	bignum	n			"
	 *	bignum	d			"
	 *	bignum	iqmp			"
	 *	bignum	p			"
	 *	bignum	q			"
	 */
	buffer_init(&m);
	buffer_put_cstring(&m, buffer_ptr(conf));

	if (sensitive_data.server_key != NULL &&
	    sensitive_data.server_key->type == KEY_RSA1) {
		buffer_put_int(&m, 1);
		buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
		buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
		buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
		buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
		buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
		buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
	} else
		buffer_put_int(&m, 0);

	if (ssh_msg_send(fd, 0, &m) == -1)
		fatal("%s: ssh_msg_send failed", __func__);

	buffer_free(&m);

	debug3("%s: done", __func__);
}
Exemplo n.º 7
0
int
main(int argc, char **argv)
{
	Buffer b;
	Options options;
#define NUM_KEYTYPES 3
	Key *keys[NUM_KEYTYPES], *key = NULL;
	struct passwd *pw;
	int key_fd[NUM_KEYTYPES], i, found, version = 2, fd;
	u_char *signature, *data;
	char *host;
	u_int slen, dlen;
	u_int32_t rnd[256];

	/* Ensure that stdin and stdout are connected */
	if ((fd = open(_PATH_DEVNULL, O_RDWR)) < 2)
		exit(1);
	/* Leave /dev/null fd iff it is attached to stderr */
	if (fd > 2)
		close(fd);

	i = 0;
	key_fd[i++] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
	key_fd[i++] = open(_PATH_HOST_ECDSA_KEY_FILE, O_RDONLY);
	key_fd[i++] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);

	original_real_uid = getuid();	/* XXX readconf.c needs this */
	if ((pw = getpwuid(original_real_uid)) == NULL)
		fatal("getpwuid failed");
	pw = pwcopy(pw);

	permanently_set_uid(pw);

#ifdef DEBUG_SSH_KEYSIGN
	log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
#endif

	/* verify that ssh-keysign is enabled by the admin */
	initialize_options(&options);
	(void)read_config_file(_PATH_HOST_CONFIG_FILE, "", &options, 0);
	fill_default_options(&options);
	if (options.enable_ssh_keysign != 1)
		fatal("ssh-keysign not enabled in %s",
		    _PATH_HOST_CONFIG_FILE);

	for (i = found = 0; i < NUM_KEYTYPES; i++) {
		if (key_fd[i] != -1)
			found = 1;
	}
	if (found == 0)
		fatal("could not open any host key");

	OpenSSL_add_all_algorithms();
	for (i = 0; i < 256; i++)
		rnd[i] = arc4random();
	RAND_seed(rnd, sizeof(rnd));

	found = 0;
	for (i = 0; i < NUM_KEYTYPES; i++) {
		keys[i] = NULL;
		if (key_fd[i] == -1)
			continue;
		keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
		    NULL, NULL);
		close(key_fd[i]);
		if (keys[i] != NULL)
			found = 1;
	}
	if (!found)
		fatal("no hostkey found");

	buffer_init(&b);
	if (ssh_msg_recv(STDIN_FILENO, &b) < 0)
		fatal("ssh_msg_recv failed");
	if (buffer_get_char(&b) != version)
		fatal("bad version");
	fd = buffer_get_int(&b);
	if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
		fatal("bad fd");
	if ((host = get_local_name(fd)) == NULL)
		fatal("cannot get local name for fd");

	data = buffer_get_string(&b, &dlen);
	if (valid_request(pw, host, &key, data, dlen) < 0)
		fatal("not a valid request");
	xfree(host);

	found = 0;
	for (i = 0; i < NUM_KEYTYPES; i++) {
		if (keys[i] != NULL &&
		    key_equal_public(key, keys[i])) {
			found = 1;
			break;
		}
	}
	if (!found)
		fatal("no matching hostkey found");

	if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
		fatal("key_sign failed");
	xfree(data);

	/* send reply */
	buffer_clear(&b);
	buffer_put_string(&b, signature, slen);
	if (ssh_msg_send(STDOUT_FILENO, version, &b) == -1)
		fatal("ssh_msg_send failed");

	return (0);
}
Exemplo n.º 8
0
/*
 * Authentication thread.
 */
static void *
sshpam_thread(void *ctxtp)
{
	struct pam_ctxt *ctxt = ctxtp;
	Buffer buffer;
	struct pam_conv sshpam_conv;
	int flags = (options.permit_empty_passwd == 0 ?
	    PAM_DISALLOW_NULL_AUTHTOK : 0);
#ifndef UNSUPPORTED_POSIX_THREADS_HACK
	extern char **environ;
	char **env_from_pam;
	u_int i;
	const char *pam_user;
	const char **ptr_pam_user = &pam_user;
	char *tz = getenv("TZ");

	sshpam_err = pam_get_item(sshpam_handle, PAM_USER,
	    (sshpam_const void **)ptr_pam_user);
	if (sshpam_err != PAM_SUCCESS)
		goto auth_fail;

	environ[0] = NULL;
	if (tz != NULL)
		if (setenv("TZ", tz, 1) == -1)
			error("PAM: could not set TZ environment: %s",
			    strerror(errno));

	if (sshpam_authctxt != NULL) {
		setproctitle("%s [pam]",
		    sshpam_authctxt->valid ? pam_user : "******");
	}
#endif

	sshpam_conv.conv = sshpam_thread_conv;
	sshpam_conv.appdata_ptr = ctxt;

	if (sshpam_authctxt == NULL)
		fatal("%s: PAM authctxt not initialized", __func__);

	buffer_init(&buffer);
	sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
	    (const void *)&sshpam_conv);
	if (sshpam_err != PAM_SUCCESS)
		goto auth_fail;
	sshpam_err = pam_authenticate(sshpam_handle, flags);
	if (sshpam_err != PAM_SUCCESS)
		goto auth_fail;

	if (compat20) {
		if (!do_pam_account()) {
			sshpam_err = PAM_ACCT_EXPIRED;
			goto auth_fail;
		}
		if (sshpam_authctxt->force_pwchange) {
			sshpam_err = pam_chauthtok(sshpam_handle,
			    PAM_CHANGE_EXPIRED_AUTHTOK);
			if (sshpam_err != PAM_SUCCESS)
				goto auth_fail;
			sshpam_password_change_required(0);
		}
	}

	buffer_put_cstring(&buffer, "OK");

#ifndef UNSUPPORTED_POSIX_THREADS_HACK
	/* Export variables set by do_pam_account */
	buffer_put_int(&buffer, sshpam_account_status);
	buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);

	/* Export any environment strings set in child */
	for(i = 0; environ[i] != NULL; i++)
		; /* Count */
	buffer_put_int(&buffer, i);
	for(i = 0; environ[i] != NULL; i++)
		buffer_put_cstring(&buffer, environ[i]);

	/* Export any environment strings set by PAM in child */
	env_from_pam = pam_getenvlist(sshpam_handle);
	for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
		; /* Count */
	buffer_put_int(&buffer, i);
	for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
		buffer_put_cstring(&buffer, env_from_pam[i]);
#endif /* UNSUPPORTED_POSIX_THREADS_HACK */

	/* XXX - can't do much about an error here */
	ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
	buffer_free(&buffer);
	pthread_exit(NULL);

 auth_fail:
	buffer_put_cstring(&buffer,
	    pam_strerror(sshpam_handle, sshpam_err));
	/* XXX - can't do much about an error here */
	if (sshpam_err == PAM_ACCT_EXPIRED)
		ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer);
	else
		ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
	buffer_free(&buffer);
	pthread_exit(NULL);

	return (NULL); /* Avoid warning for non-pthread case */
}
Exemplo n.º 9
0
/*
 * Conversation function for authentication thread.
 */
static int
sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
    struct pam_response **resp, void *data)
{
	Buffer buffer;
	struct pam_ctxt *ctxt;
	struct pam_response *reply;
	int i;

	debug3("PAM: %s entering, %d messages", __func__, n);
	*resp = NULL;

	if (data == NULL) {
		error("PAM: conversation function passed a null context");
		return (PAM_CONV_ERR);
	}
	ctxt = data;
	if (n <= 0 || n > PAM_MAX_NUM_MSG)
		return (PAM_CONV_ERR);

	if ((reply = calloc(n, sizeof(*reply))) == NULL)
		return (PAM_CONV_ERR);

	buffer_init(&buffer);
	for (i = 0; i < n; ++i) {
		switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
		case PAM_PROMPT_ECHO_OFF:
			buffer_put_cstring(&buffer,
			    PAM_MSG_MEMBER(msg, i, msg));
			if (ssh_msg_send(ctxt->pam_csock,
			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
				goto fail;
			if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
				goto fail;
			if (buffer_get_char(&buffer) != PAM_AUTHTOK)
				goto fail;
			reply[i].resp = buffer_get_string(&buffer, NULL);
			break;
		case PAM_PROMPT_ECHO_ON:
			buffer_put_cstring(&buffer,
			    PAM_MSG_MEMBER(msg, i, msg));
			if (ssh_msg_send(ctxt->pam_csock,
			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
				goto fail;
			if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
				goto fail;
			if (buffer_get_char(&buffer) != PAM_AUTHTOK)
				goto fail;
			reply[i].resp = buffer_get_string(&buffer, NULL);
			break;
		case PAM_ERROR_MSG:
			buffer_put_cstring(&buffer,
			    PAM_MSG_MEMBER(msg, i, msg));
			if (ssh_msg_send(ctxt->pam_csock,
			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
				goto fail;
			break;
		case PAM_TEXT_INFO:
			buffer_put_cstring(&buffer,
			    PAM_MSG_MEMBER(msg, i, msg));
			if (ssh_msg_send(ctxt->pam_csock,
			    PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
				goto fail;
			break;
		default:
			goto fail;
		}
		buffer_clear(&buffer);
	}
	buffer_free(&buffer);
	*resp = reply;
	return (PAM_SUCCESS);

 fail:
	for(i = 0; i < n; i++) {
		free(reply[i].resp);
	}
	free(reply);
	buffer_free(&buffer);
	return (PAM_CONV_ERR);
}
Exemplo n.º 10
0
/*
 * Conversation function for authentication thread.
 */
static int
sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
    struct pam_response **resp, void *data)
{
	struct sshbuf *buffer;
	struct pam_ctxt *ctxt;
	struct pam_response *reply;
	int r, i;
	u_char status;

	debug3("PAM: %s entering, %d messages", __func__, n);
	*resp = NULL;

	if (data == NULL) {
		error("PAM: conversation function passed a null context");
		return (PAM_CONV_ERR);
	}
	ctxt = data;
	if (n <= 0 || n > PAM_MAX_NUM_MSG)
		return (PAM_CONV_ERR);

	if ((reply = calloc(n, sizeof(*reply))) == NULL)
		return PAM_CONV_ERR;
	if ((buffer = sshbuf_new()) == NULL) {
		free(reply);
		return PAM_CONV_ERR;
	}

	for (i = 0; i < n; ++i) {
		switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
		case PAM_PROMPT_ECHO_OFF:
		case PAM_PROMPT_ECHO_ON:
			if ((r = sshbuf_put_cstring(buffer,
			    PAM_MSG_MEMBER(msg, i, msg))) != 0)
				fatal("%s: buffer error: %s",
				    __func__, ssh_err(r));
			if (ssh_msg_send(ctxt->pam_csock,
			    PAM_MSG_MEMBER(msg, i, msg_style), buffer) == -1)
				goto fail;

			if (ssh_msg_recv(ctxt->pam_csock, buffer) == -1)
				goto fail;
			if ((r = sshbuf_get_u8(buffer, &status)) != 0)
				fatal("%s: buffer error: %s",
				    __func__, ssh_err(r));
			if (status != PAM_AUTHTOK)
				goto fail;
			if ((r = sshbuf_get_cstring(buffer,
			    &reply[i].resp, NULL)) != 0)
				fatal("%s: buffer error: %s",
				    __func__, ssh_err(r));
			break;
		case PAM_ERROR_MSG:
		case PAM_TEXT_INFO:
			if ((r = sshbuf_put_cstring(buffer,
			    PAM_MSG_MEMBER(msg, i, msg))) != 0)
				fatal("%s: buffer error: %s",
				    __func__, ssh_err(r));
			if (ssh_msg_send(ctxt->pam_csock,
			    PAM_MSG_MEMBER(msg, i, msg_style), buffer) == -1)
				goto fail;
			break;
		default:
			goto fail;
		}
		sshbuf_reset(buffer);
	}
	sshbuf_free(buffer);
	*resp = reply;
	return (PAM_SUCCESS);

 fail:
	for(i = 0; i < n; i++) {
		free(reply[i].resp);
	}
	free(reply);
	sshbuf_free(buffer);
	return (PAM_CONV_ERR);
}
Exemplo n.º 11
0
int
main(int argc, char **argv)
{
	struct sshbuf *b;
	Options options;
#define NUM_KEYTYPES 4
	struct sshkey *keys[NUM_KEYTYPES], *key = NULL;
	struct passwd *pw;
	int r, key_fd[NUM_KEYTYPES], i, found, version = 2, fd;
	u_char *signature, *data, rver;
	char *host, *fp;
	size_t slen, dlen;
#ifdef WITH_OPENSSL
	u_int32_t rnd[256];
#endif

	if (pledge("stdio rpath getpw dns id", NULL) != 0)
		fatal("%s: pledge: %s", __progname, strerror(errno));

	/* Ensure that stdin and stdout are connected */
	if ((fd = open(_PATH_DEVNULL, O_RDWR)) < 2)
		exit(1);
	/* Leave /dev/null fd iff it is attached to stderr */
	if (fd > 2)
		close(fd);

	i = 0;
	/* XXX This really needs to read sshd_config for the paths */
	key_fd[i++] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
	key_fd[i++] = open(_PATH_HOST_ECDSA_KEY_FILE, O_RDONLY);
	key_fd[i++] = open(_PATH_HOST_ED25519_KEY_FILE, O_RDONLY);
	key_fd[i++] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);

	original_real_uid = getuid();	/* XXX readconf.c needs this */
	if ((pw = getpwuid(original_real_uid)) == NULL)
		fatal("getpwuid failed");
	pw = pwcopy(pw);

	permanently_set_uid(pw);

	seed_rng();

#ifdef DEBUG_SSH_KEYSIGN
	log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
#endif

	/* verify that ssh-keysign is enabled by the admin */
	initialize_options(&options);
	(void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, "", "", &options, 0);
	fill_default_options(&options);
	if (options.enable_ssh_keysign != 1)
		fatal("ssh-keysign not enabled in %s",
		    _PATH_HOST_CONFIG_FILE);

	for (i = found = 0; i < NUM_KEYTYPES; i++) {
		if (key_fd[i] != -1)
			found = 1;
	}
	if (found == 0)
		fatal("could not open any host key");

#ifdef WITH_OPENSSL
	OpenSSL_add_all_algorithms();
	arc4random_buf(rnd, sizeof(rnd));
	RAND_seed(rnd, sizeof(rnd));
#endif

	found = 0;
	for (i = 0; i < NUM_KEYTYPES; i++) {
		keys[i] = NULL;
		if (key_fd[i] == -1)
			continue;
		r = sshkey_load_private_type_fd(key_fd[i], KEY_UNSPEC,
		    NULL, &key, NULL);
		close(key_fd[i]);
		if (r != 0)
			debug("parse key %d: %s", i, ssh_err(r));
		else if (key != NULL) {
			keys[i] = key;
			found = 1;
		}
	}
	if (!found)
		fatal("no hostkey found");

	if (pledge("stdio dns", NULL) != 0)
		fatal("%s: pledge: %s", __progname, strerror(errno));

	if ((b = sshbuf_new()) == NULL)
		fatal("%s: sshbuf_new failed", __progname);
	if (ssh_msg_recv(STDIN_FILENO, b) < 0)
		fatal("ssh_msg_recv failed");
	if ((r = sshbuf_get_u8(b, &rver)) != 0)
		fatal("%s: buffer error: %s", __progname, ssh_err(r));
	if (rver != version)
		fatal("bad version: received %d, expected %d", rver, version);
	if ((r = sshbuf_get_u32(b, (u_int *)&fd)) != 0)
		fatal("%s: buffer error: %s", __progname, ssh_err(r));
	if (fd < 0 || fd == STDIN_FILENO || fd == STDOUT_FILENO)
		fatal("bad fd");
	if ((host = get_local_name(fd)) == NULL)
		fatal("cannot get local name for fd");

	if ((r = sshbuf_get_string(b, &data, &dlen)) != 0)
		fatal("%s: buffer error: %s", __progname, ssh_err(r));
	if (valid_request(pw, host, &key, data, dlen) < 0)
		fatal("not a valid request");
	free(host);

	found = 0;
	for (i = 0; i < NUM_KEYTYPES; i++) {
		if (keys[i] != NULL &&
		    sshkey_equal_public(key, keys[i])) {
			found = 1;
			break;
		}
	}
	if (!found) {
		if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
		    SSH_FP_DEFAULT)) == NULL)
			fatal("%s: sshkey_fingerprint failed", __progname);
		fatal("no matching hostkey found for key %s %s",
		    sshkey_type(key), fp ? fp : "");
	}

	if ((r = sshkey_sign(keys[i], &signature, &slen, data, dlen, NULL, 0))
	    != 0)
		fatal("sshkey_sign failed: %s", ssh_err(r));
	free(data);

	/* send reply */
	sshbuf_reset(b);
	if ((r = sshbuf_put_string(b, signature, slen)) != 0)
		fatal("%s: buffer error: %s", __progname, ssh_err(r));
	if (ssh_msg_send(STDOUT_FILENO, version, b) == -1)
		fatal("ssh_msg_send failed");

	return (0);
}