usr.bin/lock/lock.c

   1 /*      $NetBSD: lock.c,v 1.33 2013/10/18 20:47:06 christos Exp $       */
   2
   3 /*
   4  * Copyright (c) 1980, 1987, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Bob Toxen.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 __COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1993\
  38  The Regents of the University of California.  All rights reserved.");
  39 #endif /* not lint */
  40
  41 #ifndef lint
  42 #if 0
  43 static char sccsid[] = "@(#)lock.c      8.1 (Berkeley) 6/6/93";
  44 #endif
  45 __RCSID("$NetBSD: lock.c,v 1.33 2013/10/18 20:47:06 christos Exp $");
  46 #endif /* not lint */
  47
  48 /*
  49  * Lock a terminal up until the given key is entered, until the root
  50  * password is entered, or the given interval times out.
  51  *
  52  * Timeout interval is by default TIMEOUT, it can be changed with
  53  * an argument of the form -time where time is in minutes
  54  */
  55
  56 #include <sys/param.h>
  57 #include <sys/stat.h>
  58 #include <sys/time.h>
  59 #include <signal.h>
  60
  61 #include <err.h>
  62 #include <pwd.h>
  63 #include <errno.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67 #include <termios.h>
  68 #include <time.h>
  69 #include <unistd.h>
  70
  71 #ifdef USE_PAM
  72 #include <security/pam_appl.h>
  73 #include <security/openpam.h>   /* for openpam_ttyconv() */
  74 #endif
  75
  76 #ifdef SKEY
  77 #include <skey.h>
  78 #endif
  79
  80
  81 #define TIMEOUT 15
  82
  83 int     main(int, char **);
  84
  85 static void     bye(int) __dead;
  86 static void     hi(int);
  87 static void     quit(int) __dead;
  88 #ifdef SKEY
  89 static int      skey_auth(const char *);
  90 #endif
  91
  92 static struct timeval   timeout;
  93 static struct timeval   zerotime;
  94 static struct termios   tty, ntty;
  95 static int      notimeout;                      /* no timeout at all */
  96 static long     nexttime;                       /* keep the timeout time */
  97
  98 int
  99 main(int argc, char **argv)
 100 {
 101         struct passwd *pw;
 102         struct timeval timval;
 103         struct itimerval ntimer, otimer;
 104         struct tm *timp;
 105         time_t curtime;
 106         int ch, usemine;
 107         long sectimeout;
 108         char *ap, *ttynam;
 109         const char *tzn;
 110         uid_t uid = getuid();
 111         char hostname[MAXHOSTNAMELEN + 1], s[BUFSIZ], s1[BUFSIZ];
 112 #ifdef USE_PAM
 113         pam_handle_t *pamh = NULL;
 114         static const struct pam_conv pamc = { &openpam_ttyconv, NULL };
 115         int pam_err;
 116 #else
 117         char *mypw = NULL;
 118 #endif
 119
 120         if ((pw = getpwuid(getuid())) == NULL)
 121                 errx(1, "unknown uid %lu.", (u_long)uid);
 122
 123         notimeout = 0;
 124         sectimeout = TIMEOUT;
 125         usemine = 0;
 126
 127         while ((ch = getopt(argc, argv, "npt:")) != -1)
 128                 switch ((char)ch) {
 129                 case 'n':
 130                         notimeout = 1;
 131                         break;
 132                 case 't':
 133                         errno = 0;
 134                         if (((sectimeout = strtol(optarg, &ap, 0)) == LONG_MAX
 135                             || sectimeout == LONG_MIN)
 136                             && errno == ERANGE)
 137                                 err(1, "illegal timeout value: %s", optarg);
 138                         if (optarg == ap || *ap || sectimeout <= 0)
 139                                 errx(1, "illegal timeout value: %s", optarg);
 140                         if (sectimeout >= INT_MAX / 60)
 141                                 errx(1, "too large timeout value: %ld",
 142                                     sectimeout);
 143                         break;
 144                 case 'p':
 145                         usemine = 1;
 146 #ifndef USE_PAM
 147                         mypw = strdup(pw->pw_passwd);
 148                         if (!mypw)
 149                                 err(1, "strdup");
 150 #endif
 151                         break;
 152                 case '?':
 153                 default:
 154                         (void)fprintf(stderr,
 155                             "usage: %s [-np] [-t timeout]\n", getprogname());
 156                         exit(1);
 157                 }
 158
 159 #if defined(USE_PAM) || defined(SKEY)
 160         if (! usemine) {        /* -p with PAM or S/key needs privs */
 161 #endif
 162         if (setuid(uid) == -1)  /* discard privs */
 163                 err(1, "setuid failed");
 164 #if defined(USE_PAM) || defined(SKEY)
 165         }
 166 #endif
 167
 168         timeout.tv_sec = (int)sectimeout * 60;
 169
 170         if (tcgetattr(STDIN_FILENO, &tty) < 0)  /* get information for header */
 171                 err(1, "tcgetattr failed");
 172         gethostname(hostname, sizeof(hostname));
 173         hostname[sizeof(hostname) - 1] = '\0';
 174         if (!(ttynam = ttyname(STDIN_FILENO)))
 175                 err(1, "ttyname failed");
 176         if (gettimeofday(&timval, NULL) == -1)
 177                 err(1, "gettimeofday failed");
 178         curtime = timval.tv_sec;
 179         nexttime = timval.tv_sec + ((int)sectimeout * 60);
 180         timp = localtime(&curtime);
 181         ap = asctime(timp);
 182 #ifdef __SVR4
 183         tzn = tzname[0];
 184 #else
 185         tzn = timp->tm_zone;
 186 #endif
 187
 188         if (signal(SIGINT, quit) == SIG_ERR)
 189                 err(1, "signal failed");
 190         if (signal(SIGQUIT, quit) == SIG_ERR)
 191                 err(1, "signal failed");
 192         ntty = tty; ntty.c_lflag &= ~ECHO;
 193         if (tcsetattr(STDIN_FILENO, TCSADRAIN, &ntty) == -1)
 194                 err(1, "tcsetattr");
 195
 196         if (!usemine) {
 197                 /* get key and check again */
 198                 (void)printf("Key: ");
 199                 if (!fgets(s, sizeof(s), stdin) || *s == '\n')
 200                         quit(0);
 201                 (void)printf("\nAgain: ");
 202                 /*
 203                  * Don't need EOF test here, if we get EOF, then s1 != s
 204                  * and the right things will happen.
 205                  */
 206                 (void)fgets(s1, sizeof(s1), stdin);
 207                 (void)putchar('\n');
 208                 if (strcmp(s1, s)) {
 209                         (void)printf("\alock: passwords didn't match.\n");
 210                         (void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
 211                         exit(1);
 212                 }
 213                 s[0] = '\0';
 214 #ifndef USE_PAM
 215                 mypw = s1;
 216 #endif
 217         }
 218 #ifdef USE_PAM
 219         if (usemine) {
 220                 pam_err = pam_start("lock", pw->pw_name, &pamc, &pamh);
 221                 if (pam_err != PAM_SUCCESS)
 222                         err(1, "pam_start: %s", pam_strerror(NULL, pam_err));
 223         }
 224 #endif
 225
 226         /* set signal handlers */
 227         if (signal(SIGINT, hi) == SIG_ERR)
 228                 err(1, "signal failed");
 229         if (signal(SIGQUIT, hi) == SIG_ERR)
 230                 err(1, "signal failed");
 231         if (signal(SIGTSTP, hi) == SIG_ERR)
 232                 err(1, "signal failed");
 233
 234         if (notimeout) {
 235                 if (signal(SIGALRM, hi) == SIG_ERR)
 236                         err(1, "signal failed");
 237                 (void)printf("lock: %s on %s.  no timeout.\n"
 238                     "time now is %.20s%s%s",
 239                     ttynam, hostname, ap, tzn, ap + 19);
 240         }
 241         else {
 242                 if (signal(SIGALRM, bye) == SIG_ERR)
 243                         err(1, "signal failed");
 244
 245                 ntimer.it_interval = zerotime;
 246                 ntimer.it_value = timeout;
 247                 if (setitimer(ITIMER_REAL, &ntimer, &otimer) == -1)
 248                         err(1, "setitimer failed");
 249
 250                 /* header info */
 251                 (void)printf("lock: %s on %s. timeout in %ld minutes\n"
 252                     "time now is %.20s%s%s",
 253                     ttynam, hostname, sectimeout, ap, tzn, ap + 19);
 254         }
 255
 256         for (;;) {
 257 #ifdef USE_PAM
 258                 if (usemine) {
 259                         pam_err = pam_authenticate(pamh, 0);
 260                         if (pam_err == PAM_SUCCESS)
 261                                 break;
 262                         goto tryagain;
 263                 }
 264 #endif
 265                 (void)printf("Key: ");
 266                 if (!fgets(s, sizeof(s), stdin)) {
 267                         clearerr(stdin);
 268                         hi(0);
 269                         goto tryagain;
 270                 }
 271 #ifndef USE_PAM
 272                 if (usemine) {
 273                         s[strlen(s) - 1] = '\0';
 274 #ifdef SKEY
 275                         if (strcasecmp(s, "s/key") == 0) {
 276                                 if (skey_auth(pw->pw_name))
 277                                         break;
 278                         }
 279 #endif
 280                         if (!strcmp(mypw, crypt(s, mypw)))
 281                                 break;
 282                 }
 283                 else
 284 #endif
 285                         if (!strcmp(s, s1))
 286                                 break;
 287                 (void)printf("\a\n");
 288  tryagain:
 289                 if (tcsetattr(STDIN_FILENO, TCSADRAIN, &ntty) == -1
 290                     && errno != EINTR)
 291                         err(1, "tcsetattr failed");
 292         }
 293 #ifdef USE_PAM
 294         if (usemine) {
 295                 (void)pam_end(pamh, pam_err);
 296         }
 297 #endif
 298         quit(0);
 299         /* NOTREACHED */
 300         return 0;
 301 }
 302
 303 #ifdef SKEY
 304 /*
 305  * We can't use libskey's skey_authenticate() since it
 306  * handles signals in a way that's inappropriate
 307  * for our needs. Instead we roll our own.
 308  */
 309 static int
 310 skey_auth(const char *user)
 311 {
 312         char s[128];
 313         const char *ask;
 314         int ret = 0;
 315
 316         if (!skey_haskey(user) && (ask = skey_keyinfo(user))) {
 317                 (void)printf("\n[%s]\nResponse: ", ask);
 318                 if (!fgets(s, sizeof(s), stdin) || *s == '\n')
 319                         clearerr(stdin);
 320                 else {
 321                         s[strlen(s) - 1] = '\0';
 322                         if (skey_passcheck(user, s) != -1)
 323                                 ret = 1;
 324                 }
 325         } else
 326                 (void)printf("Sorry, you have no s/key.\n");
 327         return ret;
 328 }
 329 #endif
 330
 331 static void
 332 hi(int dummy)
 333 {
 334         struct timeval timval;
 335
 336         if (notimeout)
 337                 (void)printf("lock: type in the unlock key.\n");
 338         else {
 339                 if (gettimeofday(&timval, NULL) == -1)
 340                         err(1, "gettimeofday failed");
 341                 (void)printf("lock: type in the unlock key. "
 342                     "timeout in %lld:%lld minutes\n",
 343                     (long long)(nexttime - timval.tv_sec) / 60,
 344                     (long long)(nexttime - timval.tv_sec) % 60);
 345         }
 346 }
 347
 348 static void
 349 quit(int dummy)
 350 {
 351         (void)putchar('\n');
 352         (void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
 353         exit(0);
 354 }
 355
 356 static void
 357 bye(int dummy)
 358 {
 359         (void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
 360         (void)printf("lock: timeout\n");
 361         exit(1);
 362 }