auth2-chall.c revision 162856
1162856Sdes/* $OpenBSD: auth2-chall.c,v 1.31 2006/08/05 08:28:24 dtucker Exp $ */ 276259Sgreen/* 376259Sgreen * Copyright (c) 2001 Markus Friedl. All rights reserved. 492555Sdes * Copyright (c) 2001 Per Allansson. All rights reserved. 576259Sgreen * 676259Sgreen * Redistribution and use in source and binary forms, with or without 776259Sgreen * modification, are permitted provided that the following conditions 876259Sgreen * are met: 976259Sgreen * 1. Redistributions of source code must retain the above copyright 1076259Sgreen * notice, this list of conditions and the following disclaimer. 1176259Sgreen * 2. Redistributions in binary form must reproduce the above copyright 1276259Sgreen * notice, this list of conditions and the following disclaimer in the 1376259Sgreen * documentation and/or other materials provided with the distribution. 1476259Sgreen * 1576259Sgreen * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1676259Sgreen * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1776259Sgreen * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1876259Sgreen * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1976259Sgreen * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2076259Sgreen * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2176259Sgreen * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2276259Sgreen * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2376259Sgreen * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2476259Sgreen * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2576259Sgreen */ 26162856Sdes 2776259Sgreen#include "includes.h" 28162856Sdes__RCSID("$FreeBSD: head/crypto/openssh/auth2-chall.c 162856 2006-09-30 13:38:06Z des $"); 2976259Sgreen 30162856Sdes#include <sys/types.h> 31162856Sdes 32162856Sdes#include <stdarg.h> 33162856Sdes#include <stdio.h> 34162856Sdes#include <string.h> 35162856Sdes 36162856Sdes#include "xmalloc.h" 3776259Sgreen#include "ssh2.h" 38162856Sdes#include "key.h" 39162856Sdes#include "hostfile.h" 4076259Sgreen#include "auth.h" 4192555Sdes#include "buffer.h" 4276259Sgreen#include "packet.h" 4376259Sgreen#include "dispatch.h" 4476259Sgreen#include "log.h" 45147005Sdes#include "servconf.h" 4676259Sgreen 47147005Sdes/* import */ 48147005Sdesextern ServerOptions options; 49147005Sdes 5092555Sdesstatic int auth2_challenge_start(Authctxt *); 5192555Sdesstatic int send_userauth_info_request(Authctxt *); 5292555Sdesstatic void input_userauth_info_response(int, u_int32_t, void *); 5376259Sgreen 5492555Sdes#ifdef BSD_AUTH 5592555Sdesextern KbdintDevice bsdauth_device; 5698941Sdes#else 5799052Sdes#ifdef USE_PAM 58124211Sdesextern KbdintDevice sshpam_device; 5999052Sdes#endif 6098941Sdes#ifdef SKEY 6192555Sdesextern KbdintDevice skey_device; 6292555Sdes#endif 6398941Sdes#endif 6492555Sdes 6592555SdesKbdintDevice *devices[] = { 6692555Sdes#ifdef BSD_AUTH 6792555Sdes &bsdauth_device, 6898941Sdes#else 6999052Sdes#ifdef USE_PAM 70124211Sdes &sshpam_device, 7199052Sdes#endif 7298941Sdes#ifdef SKEY 7392555Sdes &skey_device, 7492555Sdes#endif 7598941Sdes#endif 7692555Sdes NULL 7792555Sdes}; 7892555Sdes 7992555Sdestypedef struct KbdintAuthctxt KbdintAuthctxt; 8092555Sdesstruct KbdintAuthctxt 8192555Sdes{ 8292555Sdes char *devices; 8392555Sdes void *ctxt; 8492555Sdes KbdintDevice *device; 8599063Sdes u_int nreq; 8692555Sdes}; 8792555Sdes 88147005Sdes#ifdef USE_PAM 89147005Sdesvoid 90147005Sdesremove_kbdint_device(const char *devname) 91147005Sdes{ 92147005Sdes int i, j; 93147005Sdes 94147005Sdes for (i = 0; devices[i] != NULL; i++) 95147005Sdes if (strcmp(devices[i]->name, devname) == 0) { 96147005Sdes for (j = i; devices[j] != NULL; j++) 97147005Sdes devices[j] = devices[j+1]; 98147005Sdes i--; 99147005Sdes } 100147005Sdes} 101147005Sdes#endif 102147005Sdes 10392555Sdesstatic KbdintAuthctxt * 10492555Sdeskbdint_alloc(const char *devs) 10592555Sdes{ 10692555Sdes KbdintAuthctxt *kbdintctxt; 10792555Sdes Buffer b; 10892555Sdes int i; 10992555Sdes 110147005Sdes#ifdef USE_PAM 111147005Sdes if (!options.use_pam) 112147005Sdes remove_kbdint_device("pam"); 113147005Sdes#endif 114147005Sdes 11592555Sdes kbdintctxt = xmalloc(sizeof(KbdintAuthctxt)); 11692555Sdes if (strcmp(devs, "") == 0) { 11792555Sdes buffer_init(&b); 11892555Sdes for (i = 0; devices[i]; i++) { 11992555Sdes if (buffer_len(&b) > 0) 12092555Sdes buffer_append(&b, ",", 1); 12192555Sdes buffer_append(&b, devices[i]->name, 12292555Sdes strlen(devices[i]->name)); 12392555Sdes } 12492555Sdes buffer_append(&b, "\0", 1); 12592555Sdes kbdintctxt->devices = xstrdup(buffer_ptr(&b)); 12692555Sdes buffer_free(&b); 12792555Sdes } else { 12892555Sdes kbdintctxt->devices = xstrdup(devs); 12992555Sdes } 13092555Sdes debug("kbdint_alloc: devices '%s'", kbdintctxt->devices); 13192555Sdes kbdintctxt->ctxt = NULL; 13292555Sdes kbdintctxt->device = NULL; 13399063Sdes kbdintctxt->nreq = 0; 13492555Sdes 13592555Sdes return kbdintctxt; 13692555Sdes} 13792555Sdesstatic void 13892555Sdeskbdint_reset_device(KbdintAuthctxt *kbdintctxt) 13992555Sdes{ 14092555Sdes if (kbdintctxt->ctxt) { 14192555Sdes kbdintctxt->device->free_ctx(kbdintctxt->ctxt); 14292555Sdes kbdintctxt->ctxt = NULL; 14392555Sdes } 14492555Sdes kbdintctxt->device = NULL; 14592555Sdes} 14692555Sdesstatic void 14792555Sdeskbdint_free(KbdintAuthctxt *kbdintctxt) 14892555Sdes{ 14992555Sdes if (kbdintctxt->device) 15092555Sdes kbdint_reset_device(kbdintctxt); 15192555Sdes if (kbdintctxt->devices) { 15292555Sdes xfree(kbdintctxt->devices); 15392555Sdes kbdintctxt->devices = NULL; 15492555Sdes } 15592555Sdes xfree(kbdintctxt); 15692555Sdes} 15792555Sdes/* get next device */ 15892555Sdesstatic int 15992555Sdeskbdint_next_device(KbdintAuthctxt *kbdintctxt) 16092555Sdes{ 16192555Sdes size_t len; 16292555Sdes char *t; 16392555Sdes int i; 16492555Sdes 16592555Sdes if (kbdintctxt->device) 16692555Sdes kbdint_reset_device(kbdintctxt); 16792555Sdes do { 16892555Sdes len = kbdintctxt->devices ? 16992555Sdes strcspn(kbdintctxt->devices, ",") : 0; 17092555Sdes 17192555Sdes if (len == 0) 17292555Sdes break; 17392555Sdes for (i = 0; devices[i]; i++) 17492555Sdes if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0) 17592555Sdes kbdintctxt->device = devices[i]; 17692555Sdes t = kbdintctxt->devices; 17792555Sdes kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL; 17892555Sdes xfree(t); 17992555Sdes debug2("kbdint_next_device: devices %s", kbdintctxt->devices ? 180149753Sdes kbdintctxt->devices : "<empty>"); 18192555Sdes } while (kbdintctxt->devices && !kbdintctxt->device); 18292555Sdes 18392555Sdes return kbdintctxt->device ? 1 : 0; 18492555Sdes} 18592555Sdes 18676259Sgreen/* 18792555Sdes * try challenge-response, set authctxt->postponed if we have to 18876259Sgreen * wait for the response. 18976259Sgreen */ 19076259Sgreenint 19176259Sgreenauth2_challenge(Authctxt *authctxt, char *devs) 19276259Sgreen{ 19392555Sdes debug("auth2_challenge: user=%s devs=%s", 19492555Sdes authctxt->user ? authctxt->user : "<nouser>", 19592555Sdes devs ? devs : "<no devs>"); 19676259Sgreen 19792555Sdes if (authctxt->user == NULL || !devs) 19876259Sgreen return 0; 19992555Sdes if (authctxt->kbdintctxt == NULL) 20092555Sdes authctxt->kbdintctxt = kbdint_alloc(devs); 20192555Sdes return auth2_challenge_start(authctxt); 20292555Sdes} 20392555Sdes 20492555Sdes/* unregister kbd-int callbacks and context */ 20592555Sdesvoid 20692555Sdesauth2_challenge_stop(Authctxt *authctxt) 20792555Sdes{ 20892555Sdes /* unregister callback */ 20992555Sdes dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL); 21092555Sdes if (authctxt->kbdintctxt != NULL) { 21192555Sdes kbdint_free(authctxt->kbdintctxt); 21292555Sdes authctxt->kbdintctxt = NULL; 21392555Sdes } 21492555Sdes} 21592555Sdes 21692555Sdes/* side effect: sets authctxt->postponed if a reply was sent*/ 21792555Sdesstatic int 21892555Sdesauth2_challenge_start(Authctxt *authctxt) 21992555Sdes{ 22092555Sdes KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt; 22192555Sdes 22292555Sdes debug2("auth2_challenge_start: devices %s", 22392555Sdes kbdintctxt->devices ? kbdintctxt->devices : "<empty>"); 22492555Sdes 22592555Sdes if (kbdint_next_device(kbdintctxt) == 0) { 22692555Sdes auth2_challenge_stop(authctxt); 22776259Sgreen return 0; 22892555Sdes } 22992555Sdes debug("auth2_challenge_start: trying authentication method '%s'", 23092555Sdes kbdintctxt->device->name); 23192555Sdes 23292555Sdes if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) { 23392555Sdes auth2_challenge_stop(authctxt); 23492555Sdes return 0; 23592555Sdes } 23692555Sdes if (send_userauth_info_request(authctxt) == 0) { 23792555Sdes auth2_challenge_stop(authctxt); 23892555Sdes return 0; 23992555Sdes } 24076259Sgreen dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, 24176259Sgreen &input_userauth_info_response); 24292555Sdes 24376259Sgreen authctxt->postponed = 1; 24476259Sgreen return 0; 24576259Sgreen} 24676259Sgreen 24792555Sdesstatic int 24892555Sdessend_userauth_info_request(Authctxt *authctxt) 24976259Sgreen{ 25092555Sdes KbdintAuthctxt *kbdintctxt; 25192555Sdes char *name, *instr, **prompts; 252149753Sdes u_int i, *echo_on; 25376259Sgreen 25492555Sdes kbdintctxt = authctxt->kbdintctxt; 25592555Sdes if (kbdintctxt->device->query(kbdintctxt->ctxt, 25699063Sdes &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on)) 25792555Sdes return 0; 25892555Sdes 25976259Sgreen packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST); 26092555Sdes packet_put_cstring(name); 26192555Sdes packet_put_cstring(instr); 26298684Sdes packet_put_cstring(""); /* language not used */ 26399063Sdes packet_put_int(kbdintctxt->nreq); 26499063Sdes for (i = 0; i < kbdintctxt->nreq; i++) { 26592555Sdes packet_put_cstring(prompts[i]); 26692555Sdes packet_put_char(echo_on[i]); 26792555Sdes } 26876259Sgreen packet_send(); 26976259Sgreen packet_write_wait(); 27092555Sdes 27199063Sdes for (i = 0; i < kbdintctxt->nreq; i++) 27292555Sdes xfree(prompts[i]); 27392555Sdes xfree(prompts); 27492555Sdes xfree(echo_on); 27592555Sdes xfree(name); 27692555Sdes xfree(instr); 27792555Sdes return 1; 27876259Sgreen} 27976259Sgreen 28092555Sdesstatic void 28192555Sdesinput_userauth_info_response(int type, u_int32_t seq, void *ctxt) 28276259Sgreen{ 28376259Sgreen Authctxt *authctxt = ctxt; 28492555Sdes KbdintAuthctxt *kbdintctxt; 285149753Sdes int authenticated = 0, res, len; 286149753Sdes u_int i, nresp; 28792555Sdes char **response = NULL, *method; 28876259Sgreen 28976259Sgreen if (authctxt == NULL) 29076259Sgreen fatal("input_userauth_info_response: no authctxt"); 29192555Sdes kbdintctxt = authctxt->kbdintctxt; 29292555Sdes if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL) 29392555Sdes fatal("input_userauth_info_response: no kbdintctxt"); 29492555Sdes if (kbdintctxt->device == NULL) 29592555Sdes fatal("input_userauth_info_response: no device"); 29676259Sgreen 29776259Sgreen authctxt->postponed = 0; /* reset */ 29876259Sgreen nresp = packet_get_int(); 29999063Sdes if (nresp != kbdintctxt->nreq) 30099063Sdes fatal("input_userauth_info_response: wrong number of replies"); 30199063Sdes if (nresp > 100) 30299063Sdes fatal("input_userauth_info_response: too many replies"); 30392555Sdes if (nresp > 0) { 304162856Sdes response = xcalloc(nresp, sizeof(char *)); 30592555Sdes for (i = 0; i < nresp; i++) 30692555Sdes response[i] = packet_get_string(NULL); 30792555Sdes } 30892555Sdes packet_check_eom(); 30992555Sdes 310147005Sdes res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response); 31192555Sdes 31292555Sdes for (i = 0; i < nresp; i++) { 31392555Sdes memset(response[i], 'r', strlen(response[i])); 31492555Sdes xfree(response[i]); 31592555Sdes } 31692555Sdes if (response) 31776259Sgreen xfree(response); 31892555Sdes 31992555Sdes switch (res) { 32092555Sdes case 0: 32192555Sdes /* Success! */ 322147005Sdes authenticated = authctxt->valid ? 1 : 0; 32392555Sdes break; 32492555Sdes case 1: 32592555Sdes /* Authentication needs further interaction */ 32692555Sdes if (send_userauth_info_request(authctxt) == 1) 32792555Sdes authctxt->postponed = 1; 32892555Sdes break; 32992555Sdes default: 33092555Sdes /* Failure! */ 33192555Sdes break; 33276259Sgreen } 33376259Sgreen 33492555Sdes len = strlen("keyboard-interactive") + 2 + 33592555Sdes strlen(kbdintctxt->device->name); 33692555Sdes method = xmalloc(len); 33792555Sdes snprintf(method, len, "keyboard-interactive/%s", 33892555Sdes kbdintctxt->device->name); 33992555Sdes 34092555Sdes if (!authctxt->postponed) { 34192555Sdes if (authenticated) { 34292555Sdes auth2_challenge_stop(authctxt); 34392555Sdes } else { 34492555Sdes /* start next device */ 34592555Sdes /* may set authctxt->postponed */ 34692555Sdes auth2_challenge_start(authctxt); 34792555Sdes } 34892555Sdes } 34976259Sgreen userauth_finish(authctxt, authenticated, method); 35092555Sdes xfree(method); 35176259Sgreen} 35298684Sdes 35398684Sdesvoid 35498684Sdesprivsep_challenge_enable(void) 35598684Sdes{ 356124211Sdes#if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY) 357124211Sdes int n = 0; 358124211Sdes#endif 35998684Sdes#ifdef BSD_AUTH 36098684Sdes extern KbdintDevice mm_bsdauth_device; 36198684Sdes#endif 36299052Sdes#ifdef USE_PAM 363124211Sdes extern KbdintDevice mm_sshpam_device; 36499052Sdes#endif 36598684Sdes#ifdef SKEY 36698684Sdes extern KbdintDevice mm_skey_device; 36798684Sdes#endif 36899052Sdes 36998684Sdes#ifdef BSD_AUTH 37099052Sdes devices[n++] = &mm_bsdauth_device; 37198684Sdes#else 37299052Sdes#ifdef USE_PAM 373124211Sdes devices[n++] = &mm_sshpam_device; 37499052Sdes#endif 37598684Sdes#ifdef SKEY 37699052Sdes devices[n++] = &mm_skey_device; 37798684Sdes#endif 37898684Sdes#endif 37998684Sdes} 380