603 lines
14 KiB
C
603 lines
14 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* Dave Safford. 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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#ifdef SRA
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#ifdef ENCRYPTION
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#include <sys/types.h>
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#include <arpa/telnet.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <ttyent.h>
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#ifndef NOPAM
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#include <security/pam_appl.h>
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#else
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#include <unistd.h>
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#endif
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#include "auth.h"
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#include "misc.h"
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#include "encrypt.h"
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#include "pk.h"
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char pka[HEXKEYBYTES+1], ska[HEXKEYBYTES+1], pkb[HEXKEYBYTES+1];
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char *user, *pass, *xuser, *xpass;
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DesData ck;
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IdeaData ik;
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extern int auth_debug_mode;
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extern char line[];
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static int sra_valid = 0;
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static int passwd_sent = 0;
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static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
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AUTHTYPE_SRA, };
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#define SRA_KEY 0
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#define SRA_USER 1
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#define SRA_CONTINUE 2
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#define SRA_PASS 3
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#define SRA_ACCEPT 4
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#define SRA_REJECT 5
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static int check_user(char *, char *);
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/* support routine to send out authentication message */
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static int
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Data(Authenticator *ap, int type, void *d, int c)
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{
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unsigned char *p = str_data + 4;
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unsigned char *cd = (unsigned char *)d;
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if (c == -1)
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c = strlen((char *)cd);
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if (auth_debug_mode) {
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printf("%s:%d: [%d] (%d)",
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str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
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str_data[3],
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type, c);
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printd(d, c);
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printf("\r\n");
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}
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*p++ = ap->type;
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*p++ = ap->way;
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*p++ = type;
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while (c-- > 0) {
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if ((*p++ = *cd++) == IAC)
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*p++ = IAC;
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}
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*p++ = IAC;
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*p++ = SE;
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if (str_data[3] == TELQUAL_IS)
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printsub('>', &str_data[2], p - (&str_data[2]));
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return(net_write(str_data, p - str_data));
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}
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int
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sra_init(Authenticator *ap __unused, int server)
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{
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if (server)
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str_data[3] = TELQUAL_REPLY;
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else
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str_data[3] = TELQUAL_IS;
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user = (char *)malloc(256);
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xuser = (char *)malloc(513);
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pass = (char *)malloc(256);
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xpass = (char *)malloc(513);
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if (user == NULL || xuser == NULL || pass == NULL || xpass ==
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NULL)
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return 0; /* malloc failed */
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passwd_sent = 0;
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genkeys(pka,ska);
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return(1);
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}
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/* client received a go-ahead for sra */
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int
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sra_send(Authenticator *ap)
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{
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/* send PKA */
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if (auth_debug_mode)
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printf("Sent PKA to server.\r\n" );
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printf("Trying SRA secure login:\r\n");
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if (!Data(ap, SRA_KEY, (void *)pka, HEXKEYBYTES)) {
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if (auth_debug_mode)
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printf("Not enough room for authentication data\r\n");
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return(0);
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}
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return(1);
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}
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/* server received an IS -- could be SRA KEY, USER, or PASS */
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void
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sra_is(Authenticator *ap, unsigned char *data, int cnt)
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{
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int valid;
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Session_Key skey;
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if (cnt-- < 1)
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goto bad;
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switch (*data++) {
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case SRA_KEY:
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if (cnt < HEXKEYBYTES) {
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Data(ap, SRA_REJECT, (void *)0, 0);
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auth_finished(ap, AUTH_USER);
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if (auth_debug_mode) {
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printf("SRA user rejected for bad PKB\r\n");
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}
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return;
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}
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if (auth_debug_mode)
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printf("Sent pka\r\n");
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if (!Data(ap, SRA_KEY, (void *)pka, HEXKEYBYTES)) {
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if (auth_debug_mode)
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printf("Not enough room\r\n");
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return;
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}
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memcpy(pkb,data,HEXKEYBYTES);
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pkb[HEXKEYBYTES] = '\0';
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common_key(ska,pkb,&ik,&ck);
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return;
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case SRA_USER:
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/* decode KAB(u) */
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if (cnt > 512) /* Attempted buffer overflow */
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break;
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memcpy(xuser,data,cnt);
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xuser[cnt] = '\0';
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pk_decode(xuser,user,&ck);
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auth_encrypt_user(user);
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Data(ap, SRA_CONTINUE, (void *)0, 0);
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return;
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case SRA_PASS:
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if (cnt > 512) /* Attempted buffer overflow */
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break;
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/* decode KAB(P) */
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memcpy(xpass,data,cnt);
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xpass[cnt] = '\0';
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pk_decode(xpass,pass,&ck);
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/* check user's password */
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valid = check_user(user,pass);
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if(valid) {
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Data(ap, SRA_ACCEPT, (void *)0, 0);
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skey.data = ck;
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skey.type = SK_DES;
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skey.length = 8;
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encrypt_session_key(&skey, 1);
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sra_valid = 1;
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auth_finished(ap, AUTH_VALID);
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if (auth_debug_mode) {
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printf("SRA user accepted\r\n");
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}
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}
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else {
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Data(ap, SRA_CONTINUE, (void *)0, 0);
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/*
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Data(ap, SRA_REJECT, (void *)0, 0);
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sra_valid = 0;
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auth_finished(ap, AUTH_REJECT);
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*/
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if (auth_debug_mode) {
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printf("SRA user failed\r\n");
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}
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}
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return;
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default:
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if (auth_debug_mode)
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printf("Unknown SRA option %d\r\n", data[-1]);
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}
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bad:
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Data(ap, SRA_REJECT, 0, 0);
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sra_valid = 0;
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auth_finished(ap, AUTH_REJECT);
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}
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/* client received REPLY -- could be SRA KEY, CONTINUE, ACCEPT, or REJECT */
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void
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sra_reply(Authenticator *ap, unsigned char *data, int cnt)
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{
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char uprompt[256],tuser[256];
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Session_Key skey;
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size_t i;
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if (cnt-- < 1)
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return;
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switch (*data++) {
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case SRA_KEY:
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/* calculate common key */
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if (cnt < HEXKEYBYTES) {
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if (auth_debug_mode) {
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printf("SRA user rejected for bad PKB\r\n");
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}
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return;
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}
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memcpy(pkb,data,HEXKEYBYTES);
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pkb[HEXKEYBYTES] = '\0';
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common_key(ska,pkb,&ik,&ck);
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enc_user:
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/* encode user */
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memset(tuser,0,sizeof(tuser));
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sprintf(uprompt,"User (%s): ",UserNameRequested);
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telnet_gets(uprompt,tuser,255,1);
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if (tuser[0] == '\n' || tuser[0] == '\r' )
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strcpy(user,UserNameRequested);
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else {
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/* telnet_gets leaves the newline on */
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for(i=0;i<sizeof(tuser);i++) {
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if (tuser[i] == '\n') {
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tuser[i] = '\0';
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break;
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}
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}
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strcpy(user,tuser);
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}
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pk_encode(user,xuser,&ck);
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/* send it off */
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if (auth_debug_mode)
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printf("Sent KAB(U)\r\n");
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if (!Data(ap, SRA_USER, (void *)xuser, strlen(xuser))) {
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if (auth_debug_mode)
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printf("Not enough room\r\n");
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return;
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}
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break;
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case SRA_CONTINUE:
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if (passwd_sent) {
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passwd_sent = 0;
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printf("[ SRA login failed ]\r\n");
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goto enc_user;
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}
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/* encode password */
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memset(pass,0,256);
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telnet_gets("Password: ",pass,255,0);
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pk_encode(pass,xpass,&ck);
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/* send it off */
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if (auth_debug_mode)
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printf("Sent KAB(P)\r\n");
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if (!Data(ap, SRA_PASS, (void *)xpass, strlen(xpass))) {
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if (auth_debug_mode)
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printf("Not enough room\r\n");
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return;
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}
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passwd_sent = 1;
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break;
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case SRA_REJECT:
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printf("[ SRA refuses authentication ]\r\n");
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printf("Trying plaintext login:\r\n");
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auth_finished(0,AUTH_REJECT);
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return;
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case SRA_ACCEPT:
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printf("[ SRA accepts you ]\r\n");
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skey.data = ck;
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skey.type = SK_DES;
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skey.length = 8;
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encrypt_session_key(&skey, 0);
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auth_finished(ap, AUTH_VALID);
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return;
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default:
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if (auth_debug_mode)
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printf("Unknown SRA option %d\r\n", data[-1]);
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return;
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}
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}
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int
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sra_status(Authenticator *ap __unused, char *name, int level)
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{
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if (level < AUTH_USER)
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return(level);
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if (UserNameRequested && sra_valid) {
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strcpy(name, UserNameRequested);
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return(AUTH_VALID);
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} else
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return(AUTH_USER);
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}
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#define BUMP(buf, len) while (*(buf)) {++(buf), --(len);}
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#define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);}
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void
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sra_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
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{
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char lbuf[32];
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int i;
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buf[buflen-1] = '\0'; /* make sure its NULL terminated */
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buflen -= 1;
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switch(data[3]) {
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case SRA_CONTINUE:
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strncpy((char *)buf, " CONTINUE ", buflen);
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goto common;
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case SRA_REJECT: /* Rejected (reason might follow) */
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strncpy((char *)buf, " REJECT ", buflen);
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goto common;
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case SRA_ACCEPT: /* Accepted (name might follow) */
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strncpy((char *)buf, " ACCEPT ", buflen);
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common:
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BUMP(buf, buflen);
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if (cnt <= 4)
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break;
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ADDC(buf, buflen, '"');
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for (i = 4; i < cnt; i++)
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ADDC(buf, buflen, data[i]);
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ADDC(buf, buflen, '"');
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ADDC(buf, buflen, '\0');
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break;
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case SRA_KEY: /* Authentication data follows */
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strncpy((char *)buf, " KEY ", buflen);
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goto common2;
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case SRA_USER:
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strncpy((char *)buf, " USER ", buflen);
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goto common2;
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case SRA_PASS:
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strncpy((char *)buf, " PASS ", buflen);
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goto common2;
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default:
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sprintf(lbuf, " %d (unknown)", data[3]);
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strncpy((char *)buf, lbuf, buflen);
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common2:
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BUMP(buf, buflen);
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for (i = 4; i < cnt; i++) {
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sprintf(lbuf, " %d", data[i]);
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strncpy((char *)buf, lbuf, buflen);
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BUMP(buf, buflen);
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}
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break;
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}
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}
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static int
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isroot(const char *usr)
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{
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struct passwd *pwd;
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if ((pwd=getpwnam(usr))==NULL)
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return 0;
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return (!pwd->pw_uid);
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}
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static int
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rootterm(char *ttyn)
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{
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struct ttyent *t;
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return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
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}
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#ifdef NOPAM
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static int
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check_user(char *name, char *cred)
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{
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char *cp;
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char *xpasswd, *salt;
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if (isroot(name) && !rootterm(line))
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{
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crypt("AA","*"); /* Waste some time to simulate success */
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return(0);
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}
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if (pw = sgetpwnam(name)) {
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if (pw->pw_shell == NULL) {
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pw = (struct passwd *) NULL;
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return(0);
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}
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salt = pw->pw_passwd;
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xpasswd = crypt(cred, salt);
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/* The strcmp does not catch null passwords! */
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if (pw == NULL || *pw->pw_passwd == '\0' ||
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strcmp(xpasswd, pw->pw_passwd)) {
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pw = (struct passwd *) NULL;
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return(0);
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}
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return(1);
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}
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return(0);
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}
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#else
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/*
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* The following is stolen from ftpd, which stole it from the imap-uw
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* PAM module and login.c. It is needed because we can't really
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* "converse" with the user, having already gone to the trouble of
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* getting their username and password through an encrypted channel.
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*/
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#define COPY_STRING(s) (s ? strdup(s):NULL)
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struct cred_t {
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const char *uname;
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const char *pass;
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};
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typedef struct cred_t cred_t;
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static int
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auth_conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata)
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{
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int i;
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cred_t *cred = (cred_t *) appdata;
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struct pam_response *reply =
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malloc(sizeof(struct pam_response) * num_msg);
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if (reply == NULL)
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return PAM_BUF_ERR;
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for (i = 0; i < num_msg; i++) {
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switch (msg[i]->msg_style) {
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case PAM_PROMPT_ECHO_ON: /* assume want user name */
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reply[i].resp_retcode = PAM_SUCCESS;
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reply[i].resp = COPY_STRING(cred->uname);
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/* PAM frees resp. */
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break;
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case PAM_PROMPT_ECHO_OFF: /* assume want password */
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reply[i].resp_retcode = PAM_SUCCESS;
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reply[i].resp = COPY_STRING(cred->pass);
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/* PAM frees resp. */
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break;
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case PAM_TEXT_INFO:
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case PAM_ERROR_MSG:
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reply[i].resp_retcode = PAM_SUCCESS;
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reply[i].resp = NULL;
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break;
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default: /* unknown message style */
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free(reply);
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return PAM_CONV_ERR;
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}
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}
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*resp = reply;
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return PAM_SUCCESS;
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}
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/*
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* The PAM version as a side effect may put a new username in *name.
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*/
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static int
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check_user(char *name, char *cred)
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{
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pam_handle_t *pamh = NULL;
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const void *item;
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int rval;
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int e;
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cred_t auth_cred = { name, cred };
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struct pam_conv conv = { &auth_conv, &auth_cred };
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e = pam_start("telnetd", name, &conv, &pamh);
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if (e != PAM_SUCCESS) {
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syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e));
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return 0;
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}
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#if 0 /* Where can we find this value? */
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e = pam_set_item(pamh, PAM_RHOST, remotehost);
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if (e != PAM_SUCCESS) {
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syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
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pam_strerror(pamh, e));
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
e = pam_authenticate(pamh, 0);
|
|
switch (e) {
|
|
case PAM_SUCCESS:
|
|
/*
|
|
* With PAM we support the concept of a "template"
|
|
* user. The user enters a login name which is
|
|
* authenticated by PAM, usually via a remote service
|
|
* such as RADIUS or TACACS+. If authentication
|
|
* succeeds, a different but related "template" name
|
|
* is used for setting the credentials, shell, and
|
|
* home directory. The name the user enters need only
|
|
* exist on the remote authentication server, but the
|
|
* template name must be present in the local password
|
|
* database.
|
|
*
|
|
* This is supported by two various mechanisms in the
|
|
* individual modules. However, from the application's
|
|
* point of view, the template user is always passed
|
|
* back as a changed value of the PAM_USER item.
|
|
*/
|
|
if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
|
|
PAM_SUCCESS) {
|
|
strcpy(name, item);
|
|
} else
|
|
syslog(LOG_ERR, "Couldn't get PAM_USER: %s",
|
|
pam_strerror(pamh, e));
|
|
if (isroot(name) && !rootterm(line))
|
|
rval = 0;
|
|
else
|
|
rval = 1;
|
|
break;
|
|
|
|
case PAM_AUTH_ERR:
|
|
case PAM_USER_UNKNOWN:
|
|
case PAM_MAXTRIES:
|
|
rval = 0;
|
|
break;
|
|
|
|
default:
|
|
syslog(LOG_ERR, "auth_pam: %s", pam_strerror(pamh, e));
|
|
rval = 0;
|
|
break;
|
|
}
|
|
|
|
if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
|
|
syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
|
|
rval = 0;
|
|
}
|
|
return rval;
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif /* ENCRYPTION */
|
|
#endif /* SRA */
|