login_skey.c revision 1.3
1/* $OpenBSD: login_skey.c,v 1.3 2001/06/25 22:10:29 millert Exp $ */ 2 3/*- 4 * Copyright (c) 1995 Berkeley Software Design, Inc. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Berkeley Software Design, 17 * Inc. 18 * 4. The name of Berkeley Software Design, Inc. may not be used to endorse 19 * or promote products derived from this software without specific prior 20 * written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN, INC. ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN, INC. BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * BSDI $From: login_skey.c,v 1.3 1996/09/04 05:24:56 prb Exp $ 35 */ 36#include <sys/types.h> 37#include <sys/param.h> 38#include <sys/stat.h> 39#include <sys/time.h> 40#include <sys/resource.h> 41 42#include <ctype.h> 43#include <fcntl.h> 44#include <paths.h> 45#include <pwd.h> 46#include <readpassphrase.h> 47#include <stdio.h> 48#include <stdlib.h> 49#include <string.h> 50#include <syslog.h> 51#include <unistd.h> 52 53#include <login_cap.h> 54#include <bsd_auth.h> 55#include <sha1.h> 56#include <skey.h> 57 58void timedout __P((int)); 59 60int 61main(argc, argv) 62 int argc; 63 char **argv; 64{ 65 FILE *back = NULL; 66 char *class = 0; 67 char *username = 0; 68 struct skey skey; 69 char skeyprompt[SKEY_MAX_CHALLENGE+17]; 70 char passbuf[SKEY_MAX_PW_LEN+1]; 71 int c, haskey; 72 int mode = 0; 73 74 skeyprompt[0] = '\0'; 75 76 (void)signal(SIGQUIT, SIG_IGN); 77 (void)signal(SIGINT, SIG_IGN); 78 (void)signal(SIGALRM, timedout); 79 (void)setpriority(PRIO_PROCESS, 0, 0); 80 81 openlog(NULL, LOG_ODELAY, LOG_AUTH); 82 83 while ((c = getopt(argc, argv, "ds:v:")) != EOF) 84 switch(c) { 85 case 'd': /* to remain undocumented */ 86 back = stdout; 87 break; 88 case 'v': 89 break; 90 case 's': /* service */ 91 if (strcmp(optarg, "login") == 0) 92 mode = 0; 93 else if (strcmp(optarg, "challenge") == 0) 94 mode = 1; 95 else if (strcmp(optarg, "response") == 0) 96 mode = 2; 97 else { 98 syslog(LOG_ERR, "%s: invalid service", optarg); 99 exit(1); 100 } 101 break; 102 default: 103 syslog(LOG_ERR, "usage error"); 104 exit(1); 105 } 106 107 switch(argc - optind) { 108 case 2: 109 class = argv[optind + 1]; 110 case 1: 111 username = argv[optind]; 112 break; 113 default: 114 syslog(LOG_ERR, "usage error"); 115 exit(1); 116 } 117 118 119 if (back == NULL && (back = fdopen(3, "r+")) == NULL) { 120 syslog(LOG_ERR, "reopening back channel: %m"); 121 exit(1); 122 } 123 124 if (mode == 2) { 125 mode = 0; 126 c = -1; 127 /* XXX - redo these loops! */ 128 while (++c < sizeof(skeyprompt) && 129 read(3, &skeyprompt[c], 1) == 1) { 130 if (skeyprompt[c] == '\0') { 131 mode++; 132 break; 133 } 134 } 135 if (mode == 1) { 136 c = -1; 137 while (++c < sizeof(passbuf) && 138 read(3, &passbuf[c], 1) == 1) { 139 if (passbuf[c] == '\0') { 140 mode++; 141 break; 142 } 143 } 144 } 145 if (mode < 2) { 146 syslog(LOG_ERR, "protocol error on back channel"); 147 exit(1); 148 } 149 /* 150 * Sigh. S/Key really is a stateful protocol. 151 * We must assume that a user will only try to 152 * authenticate one at a time and that this call to 153 * skeychallenge will produce the same results as 154 * the call to skeychallenge when mode was 1. 155 * 156 * Furthermore, RFC2289 requires that an entry be 157 * locked against a partial guess race which is 158 * simply not possible if the calling program queries 159 * the user for the passphrase itself. Oh well. 160 */ 161 haskey = (skeychallenge(&skey, username, skeyprompt) == 0); 162 } else { 163 /* 164 * Attempt an S/Key challenge. 165 * The OpenBSD skeychallenge() will always fill in a 166 * challenge, even if it has to cons one up. 167 */ 168 haskey = (skeychallenge(&skey, username, skeyprompt) == 0); 169 strcat(skeyprompt, "\nS/Key Password: "); 170 if (mode == 1) { 171 fprintf(back, BI_VALUE " challenge %s\n", 172 auth_mkvalue(skeyprompt)); 173 fprintf(back, BI_CHALLENGE "\n"); 174 exit(0); 175 } 176 177 /* Time out getting passphrase after 2 minutes to avoid a DoS */ 178 if (haskey) 179 alarm(120); 180 readpassphrase(skeyprompt, passbuf, sizeof(passbuf), 0); 181 if (passbuf[0] == '\0') 182 readpassphrase("S/Key Password [echo on]: ", 183 passbuf, sizeof(passbuf), RPP_ECHO_ON); 184 alarm(0); 185 } 186 187 if (haskey && skeyverify(&skey, passbuf) == 0) { 188 if (mode == 0) { 189 if (skey.n <= 1) 190 printf("Warning! You MUST change your " 191 "S/Key password now!\n"); 192 else if (skey.n < 5) 193 printf("Warning! Change S/Key password soon\n"); 194 } 195 fprintf(back, BI_AUTH "\n"); 196 fprintf(back, BI_SECURE "\n"); 197 exit(0); 198 } 199 fprintf(back, BI_REJECT "\n"); 200 exit(1); 201} 202 203void 204timedout(signo) 205 int signo; 206{ 207 208 _exit(1); 209} 210