GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.bin/ssh/sshd/../auth2-chall.c Lines: 0 141 0.0 %
Date: 2017-11-13 Branches: 0 85 0.0 %

Line Branch Exec Source
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/* $OpenBSD: auth2-chall.c,v 1.48 2017/05/30 14:29:59 markus Exp $ */
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/*
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 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
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 * Copyright (c) 2001 Per Allansson.  All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <sys/types.h>
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#include <stdio.h>
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#include <string.h>
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#include "xmalloc.h"
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#include "ssh2.h"
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#include "key.h"
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#include "hostfile.h"
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#include "auth.h"
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#include "buffer.h"
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#include "packet.h"
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#include "dispatch.h"
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#include "log.h"
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static int auth2_challenge_start(struct ssh *);
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static int send_userauth_info_request(Authctxt *);
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static int input_userauth_info_response(int, u_int32_t, struct ssh *);
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extern KbdintDevice bsdauth_device;
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KbdintDevice *devices[] = {
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	&bsdauth_device,
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	NULL
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};
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typedef struct KbdintAuthctxt KbdintAuthctxt;
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struct KbdintAuthctxt
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{
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	char *devices;
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	void *ctxt;
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	KbdintDevice *device;
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	u_int nreq;
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	u_int devices_done;
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};
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static KbdintAuthctxt *
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kbdint_alloc(const char *devs)
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{
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	KbdintAuthctxt *kbdintctxt;
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	Buffer b;
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	int i;
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	kbdintctxt = xcalloc(1, sizeof(KbdintAuthctxt));
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	if (strcmp(devs, "") == 0) {
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		buffer_init(&b);
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		for (i = 0; devices[i]; i++) {
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			if (buffer_len(&b) > 0)
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				buffer_append(&b, ",", 1);
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			buffer_append(&b, devices[i]->name,
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			    strlen(devices[i]->name));
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		}
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		if ((kbdintctxt->devices = sshbuf_dup_string(&b)) == NULL)
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			fatal("%s: sshbuf_dup_string failed", __func__);
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		buffer_free(&b);
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	} else {
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		kbdintctxt->devices = xstrdup(devs);
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	}
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	debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
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	kbdintctxt->ctxt = NULL;
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	kbdintctxt->device = NULL;
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	kbdintctxt->nreq = 0;
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	return kbdintctxt;
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}
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static void
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kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
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{
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	if (kbdintctxt->ctxt) {
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		kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
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		kbdintctxt->ctxt = NULL;
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	}
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	kbdintctxt->device = NULL;
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}
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static void
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kbdint_free(KbdintAuthctxt *kbdintctxt)
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{
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	if (kbdintctxt->device)
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		kbdint_reset_device(kbdintctxt);
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	free(kbdintctxt->devices);
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	explicit_bzero(kbdintctxt, sizeof(*kbdintctxt));
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	free(kbdintctxt);
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}
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/* get next device */
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static int
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kbdint_next_device(Authctxt *authctxt, KbdintAuthctxt *kbdintctxt)
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{
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	size_t len;
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	char *t;
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	int i;
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	if (kbdintctxt->device)
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		kbdint_reset_device(kbdintctxt);
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	do {
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		len = kbdintctxt->devices ?
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		    strcspn(kbdintctxt->devices, ",") : 0;
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		if (len == 0)
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			break;
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		for (i = 0; devices[i]; i++) {
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			if ((kbdintctxt->devices_done & (1 << i)) != 0 ||
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			    !auth2_method_allowed(authctxt,
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			    "keyboard-interactive", devices[i]->name))
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				continue;
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			if (strncmp(kbdintctxt->devices, devices[i]->name,
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			    len) == 0) {
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				kbdintctxt->device = devices[i];
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				kbdintctxt->devices_done |= 1 << i;
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			}
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		}
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		t = kbdintctxt->devices;
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		kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
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		free(t);
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		debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
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		    kbdintctxt->devices : "<empty>");
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	} while (kbdintctxt->devices && !kbdintctxt->device);
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	return kbdintctxt->device ? 1 : 0;
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}
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/*
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 * try challenge-response, set authctxt->postponed if we have to
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 * wait for the response.
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 */
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int
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auth2_challenge(struct ssh *ssh, char *devs)
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{
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	Authctxt *authctxt = ssh->authctxt;
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	debug("auth2_challenge: user=%s devs=%s",
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	    authctxt->user ? authctxt->user : "<nouser>",
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	    devs ? devs : "<no devs>");
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	if (authctxt->user == NULL || !devs)
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		return 0;
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	if (authctxt->kbdintctxt == NULL)
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		authctxt->kbdintctxt = kbdint_alloc(devs);
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	return auth2_challenge_start(ssh);
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}
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/* unregister kbd-int callbacks and context */
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void
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auth2_challenge_stop(struct ssh *ssh)
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{
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	Authctxt *authctxt = ssh->authctxt;
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	/* unregister callback */
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	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
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	if (authctxt->kbdintctxt != NULL) {
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		kbdint_free(authctxt->kbdintctxt);
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		authctxt->kbdintctxt = NULL;
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	}
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}
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/* side effect: sets authctxt->postponed if a reply was sent*/
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static int
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auth2_challenge_start(struct ssh *ssh)
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{
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	Authctxt *authctxt = ssh->authctxt;
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	KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
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	debug2("auth2_challenge_start: devices %s",
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	    kbdintctxt->devices ?  kbdintctxt->devices : "<empty>");
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	if (kbdint_next_device(authctxt, kbdintctxt) == 0) {
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		auth2_challenge_stop(ssh);
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		return 0;
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	}
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	debug("auth2_challenge_start: trying authentication method '%s'",
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	    kbdintctxt->device->name);
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	if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
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		auth2_challenge_stop(ssh);
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		return 0;
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	}
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	if (send_userauth_info_request(authctxt) == 0) {
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		auth2_challenge_stop(ssh);
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		return 0;
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	}
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	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE,
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	    &input_userauth_info_response);
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	authctxt->postponed = 1;
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	return 0;
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}
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static int
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send_userauth_info_request(Authctxt *authctxt)
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{
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	KbdintAuthctxt *kbdintctxt;
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	char *name, *instr, **prompts;
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	u_int i, *echo_on;
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	kbdintctxt = authctxt->kbdintctxt;
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	if (kbdintctxt->device->query(kbdintctxt->ctxt,
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	    &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
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		return 0;
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	packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
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	packet_put_cstring(name);
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	packet_put_cstring(instr);
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	packet_put_cstring("");		/* language not used */
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	packet_put_int(kbdintctxt->nreq);
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	for (i = 0; i < kbdintctxt->nreq; i++) {
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		packet_put_cstring(prompts[i]);
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		packet_put_char(echo_on[i]);
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	}
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	packet_send();
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	packet_write_wait();
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	for (i = 0; i < kbdintctxt->nreq; i++)
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		free(prompts[i]);
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	free(prompts);
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	free(echo_on);
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	free(name);
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	free(instr);
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	return 1;
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}
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static int
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input_userauth_info_response(int type, u_int32_t seq, struct ssh *ssh)
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{
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	Authctxt *authctxt = ssh->authctxt;
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	KbdintAuthctxt *kbdintctxt;
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	int authenticated = 0, res;
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	u_int i, nresp;
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	const char *devicename = NULL;
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	char **response = NULL;
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	if (authctxt == NULL)
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		fatal("input_userauth_info_response: no authctxt");
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	kbdintctxt = authctxt->kbdintctxt;
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	if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
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		fatal("input_userauth_info_response: no kbdintctxt");
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	if (kbdintctxt->device == NULL)
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		fatal("input_userauth_info_response: no device");
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	authctxt->postponed = 0;	/* reset */
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	nresp = packet_get_int();
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	if (nresp != kbdintctxt->nreq)
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		fatal("input_userauth_info_response: wrong number of replies");
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	if (nresp > 100)
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		fatal("input_userauth_info_response: too many replies");
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	if (nresp > 0) {
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		response = xcalloc(nresp, sizeof(char *));
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		for (i = 0; i < nresp; i++)
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			response[i] = packet_get_string(NULL);
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	}
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	packet_check_eom();
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	res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
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	for (i = 0; i < nresp; i++) {
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		explicit_bzero(response[i], strlen(response[i]));
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		free(response[i]);
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	}
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	free(response);
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	switch (res) {
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	case 0:
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		/* Success! */
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		authenticated = authctxt->valid ? 1 : 0;
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		break;
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	case 1:
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		/* Authentication needs further interaction */
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		if (send_userauth_info_request(authctxt) == 1)
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			authctxt->postponed = 1;
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		break;
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	default:
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		/* Failure! */
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		break;
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	}
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	devicename = kbdintctxt->device->name;
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	if (!authctxt->postponed) {
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		if (authenticated) {
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			auth2_challenge_stop(ssh);
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		} else {
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			/* start next device */
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			/* may set authctxt->postponed */
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			auth2_challenge_start(ssh);
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		}
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	}
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	userauth_finish(ssh, authenticated, "keyboard-interactive",
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	    devicename);
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	return 0;
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}
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void
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privsep_challenge_enable(void)
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{
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	extern KbdintDevice mm_bsdauth_device;
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	devices[0] = &mm_bsdauth_device;
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}