[8ad6681b] | 1 | /* $Id$ */ |
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| 2 | |
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| 3 | /* Read a password, encrypt it and compare to the encrypted |
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| 4 | * password in the TELNETD_PASSWD environment variable. |
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| 5 | * No password is required if TELNETD_PASSWD is unset |
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| 6 | */ |
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| 7 | |
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| 8 | /* |
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| 9 | * Authorship |
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| 10 | * ---------- |
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| 11 | * This software was created by |
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| 12 | * Till Straumann <strauman@slac.stanford.edu>, 2003-2007 |
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| 13 | * Stanford Linear Accelerator Center, Stanford University. |
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| 14 | * |
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| 15 | * Acknowledgement of sponsorship |
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| 16 | * ------------------------------ |
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| 17 | * This software was produced by |
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| 18 | * the Stanford Linear Accelerator Center, Stanford University, |
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| 19 | * under Contract DE-AC03-76SFO0515 with the Department of Energy. |
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| 20 | * |
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| 21 | * Government disclaimer of liability |
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| 22 | * ---------------------------------- |
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| 23 | * Neither the United States nor the United States Department of Energy, |
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| 24 | * nor any of their employees, makes any warranty, express or implied, or |
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| 25 | * assumes any legal liability or responsibility for the accuracy, |
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| 26 | * completeness, or usefulness of any data, apparatus, product, or process |
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| 27 | * disclosed, or represents that its use would not infringe privately owned |
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| 28 | * rights. |
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| 29 | * |
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| 30 | * Stanford disclaimer of liability |
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| 31 | * -------------------------------- |
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| 32 | * Stanford University makes no representations or warranties, express or |
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| 33 | * implied, nor assumes any liability for the use of this software. |
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| 34 | * |
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| 35 | * Stanford disclaimer of copyright |
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| 36 | * -------------------------------- |
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| 37 | * Stanford University, owner of the copyright, hereby disclaims its |
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| 38 | * copyright and all other rights in this software. Hence, anyone may |
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| 39 | * freely use it for any purpose without restriction. |
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| 40 | * |
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| 41 | * Maintenance of notices |
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| 42 | * ---------------------- |
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| 43 | * In the interest of clarity regarding the origin and status of this |
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| 44 | * SLAC software, this and all the preceding Stanford University notices |
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| 45 | * are to remain affixed to any copy or derivative of this software made |
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| 46 | * or distributed by the recipient and are to be affixed to any copy of |
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| 47 | * software made or distributed by the recipient that contains a copy or |
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| 48 | * derivative of this software. |
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| 49 | * |
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| 50 | * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03 |
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| 51 | */ |
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| 52 | |
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| 53 | #if !defined(INSIDE_TELNETD) && !defined(__rtems__) |
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| 54 | #include <crypt.h> |
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| 55 | #endif |
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| 56 | #include <termios.h> |
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| 57 | #include <errno.h> |
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| 58 | #include <stdio.h> |
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| 59 | #include <unistd.h> |
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| 60 | #include <stdlib.h> |
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| 61 | #include <string.h> |
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| 62 | #include <syslog.h> |
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| 63 | |
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| 64 | #include "passwd.h" |
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| 65 | |
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| 66 | /* rtems has global filedescriptors but per-thread stdio streams... */ |
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| 67 | #define STDI_FD fileno(stdin) |
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| 68 | #define MAXPASSRETRY 3 |
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| 69 | |
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| 70 | extern char *__des_crypt_r(char *, char*, char*, int); |
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| 71 | |
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| 72 | #if !defined(INSIDE_TELNETD) |
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| 73 | #define sockpeername(s,b,sz) (-1) |
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| 74 | #endif |
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| 75 | |
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| 76 | #if defined(INSIDE_TELNETD) |
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| 77 | static |
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| 78 | #endif |
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| 79 | int check_passwd(char *peername) |
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| 80 | { |
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| 81 | char *pw; |
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| 82 | int rval = -1, tmp, retries; |
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| 83 | struct termios t,told; |
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| 84 | int restore_flags = 0; |
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| 85 | char buf[30], cryptbuf[21]; |
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| 86 | char salt[3]; |
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| 87 | |
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| 88 | if ( !(pw=getenv("TELNETD_PASSWD")) || 0 == strlen(pw) ) |
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| 89 | #ifdef TELNETD_DEFAULT_PASSWD |
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| 90 | pw = TELNETD_DEFAULT_PASSWD; |
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| 91 | #else |
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| 92 | return 0; |
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| 93 | #endif |
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| 94 | |
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| 95 | if ( tcgetattr(STDI_FD, &t) ) { |
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| 96 | perror("check_passwd(): tcgetattr"); |
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| 97 | goto done; |
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| 98 | } |
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| 99 | told = t; |
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| 100 | t.c_lflag &= ~ECHO; |
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| 101 | t.c_lflag &= ~ICANON; |
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| 102 | t.c_cc[VTIME] = 255; |
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| 103 | t.c_cc[VMIN] = 0; |
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| 104 | |
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| 105 | strncpy(salt,pw,2); |
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| 106 | salt[2]=0; |
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| 107 | |
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| 108 | if ( tcsetattr(STDI_FD, TCSANOW, &t) ) { |
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| 109 | perror("check_passwd(): tcsetattr"); |
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| 110 | goto done; |
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| 111 | } |
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| 112 | restore_flags = 1; |
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| 113 | |
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| 114 | /* Here we ask for the password... */ |
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| 115 | for ( retries = MAXPASSRETRY; retries > 0; retries-- ) { |
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| 116 | fflush(stdin); |
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| 117 | fprintf(stderr,"Password:"); |
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| 118 | fflush(stderr); |
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| 119 | if ( 0 == fgets(buf,sizeof(buf),stdin) ) { |
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| 120 | /* Here comes an ugly hack: |
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| 121 | * The termios driver's 'read()' handler |
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| 122 | * returns 0 to the c library's fgets if |
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| 123 | * it times out. 'fgets' interprets this |
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| 124 | * (correctly) as EOF, a condition we want |
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| 125 | * to undo since it's not really true since |
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| 126 | * we really have a read error (termios bug??) |
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| 127 | * |
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| 128 | * As a workaround we push something back and |
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| 129 | * read it again. This should simply reset the |
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| 130 | * EOF condition. |
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| 131 | */ |
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| 132 | if (ungetc('?',stdin) >= 0) |
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| 133 | fgetc(stdin); |
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| 134 | goto done; |
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| 135 | } |
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| 136 | fputc('\n',stderr); |
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| 137 | tmp = strlen(buf); |
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| 138 | while ( tmp > 0 && ('\n' == buf[tmp-1] || '\r' == buf[tmp-1]) ) { |
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| 139 | buf[--tmp]=0; |
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| 140 | } |
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| 141 | if ( !strcmp(__des_crypt_r(buf, salt, cryptbuf, sizeof(cryptbuf)), pw) ) { |
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| 142 | rval = 0; |
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| 143 | break; |
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| 144 | } |
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| 145 | fprintf(stderr,"Incorrect Password.\n"); |
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| 146 | sleep(2); |
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| 147 | } |
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| 148 | |
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| 149 | if ( 0 == retries ) { |
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| 150 | syslog( LOG_AUTHPRIV | LOG_WARNING, |
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| 151 | "telnetd: %i wrong passwords entered from %s", |
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| 152 | MAXPASSRETRY, |
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| 153 | peername ? peername : "<UNKNOWN>"); |
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| 154 | } |
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| 155 | |
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| 156 | done: |
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| 157 | /* what to do if restoring the flags fails?? */ |
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| 158 | if (restore_flags) |
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| 159 | tcsetattr(STDI_FD, TCSANOW, &told); |
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| 160 | |
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| 161 | if (rval) { |
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| 162 | sleep(2); |
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| 163 | } |
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| 164 | return rval; |
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| 165 | } |
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| 166 | |
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| 167 | #if !defined(INSIDE_TELNETD) && !defined(__rtems__) |
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| 168 | int |
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| 169 | main(int argc, char **argv) |
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| 170 | { |
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| 171 | char *str, *enc=0; |
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| 172 | int ch; |
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| 173 | |
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| 174 | while ( (ch=getopt(argc, argv, "g:")) > 0 ) { |
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| 175 | switch (ch) { |
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| 176 | default: |
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| 177 | fprintf(stderr,"Unknown option\n"); |
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| 178 | return(1); |
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| 179 | |
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| 180 | case 'g': |
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| 181 | printf("Generated encrypted password: '%s'\n", (enc=crypt(optarg,"td"))); |
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| 182 | break; |
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| 183 | |
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| 184 | } |
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| 185 | } |
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| 186 | if (argc>optind && !enc) { |
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| 187 | enc=argv[optind]; |
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| 188 | } |
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| 189 | if (enc) { |
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| 190 | str = malloc(strlen(enc) + 30); |
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| 191 | sprintf(str,"TELNETD_PASSWD=%s",enc); |
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| 192 | putenv(str); |
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| 193 | } |
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| 194 | if (check_passwd(-1)) { |
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| 195 | fprintf(stderr,"check_passwd() failed\n"); |
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| 196 | } |
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| 197 | return 0; |
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| 198 | } |
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| 199 | |
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| 200 | #endif |
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