/* $OpenBSD: login.c,v 1.26 1998/07/13 02:11:36 millert Exp $ */ /* $NetBSD: login.c,v 1.13 1996/05/15 23:50:16 jtc Exp $ */ /*- * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint static char copyright[] = "@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\ The Regents of the University of California. All rights reserved.\n"; #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; #endif static char rcsid[] = "$OpenBSD: login.c,v 1.26 1998/07/13 02:11:36 millert Exp $"; #endif /* not lint */ /* * login [ name ] * login -h hostname (for telnetd, etc.) * login -f name (for pre-authenticated login: datakit, xterm, etc.) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pathnames.h" void badlogin __P((char *)); void checknologin __P((void)); void dolastlog __P((int)); void getloginname __P((void)); void motd __P((void)); int rootterm __P((char *)); void sigint __P((int)); void sighup __P((int)); void sleepexit __P((int)); char *stypeof __P((char *)); void timedout __P((int)); int pwcheck __P((char *, char *, char *, char *)); #if defined(KERBEROS) || defined(KERBEROS5) int klogin __P((struct passwd *, char *, char *, char *)); void kdestroy __P((void)); void dofork __P((void)); void kgettokens __P((char *)); #endif extern void login __P((struct utmp *)); extern int check_failedlogin __P((uid_t)); extern void log_failedlogin __P((uid_t, char *, char *, char *)); #define TTYGRPNAME "tty" /* name of group to own ttys */ /* * This bounds the time given to login. Not a define so it can * be patched on machines where it's too small. */ u_int timeout = 300; #if defined(KERBEROS) || defined(KERBEROS5) int notickets = 1; char *instance; char *krbtkfile_env; int authok; #endif struct passwd *pwd; int failures; char term[64], *hostname, *tty; char *username = NULL, *rusername = NULL; int main(argc, argv) int argc; char *argv[]; { extern char **environ; struct group *gr; struct stat st; struct timeval tp; struct utmp utmp; int ask, ch, cnt, fflag, hflag, pflag, uflag, quietlog, rootlogin, rval; uid_t uid; char *domain, *p, *salt, *ttyn; char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; char localhost[MAXHOSTNAMELEN]; (void)signal(SIGALRM, timedout); (void)alarm(timeout); (void)signal(SIGQUIT, SIG_IGN); (void)signal(SIGINT, SIG_IGN); (void)signal(SIGHUP, sighup); (void)setpriority(PRIO_PROCESS, 0, 0); openlog("login", LOG_ODELAY, LOG_AUTH); /* * -p is used by getty to tell login not to destroy the environment * -f is used to skip a second login authentication * -h is used by other servers to pass the name of the remote * host to login so that it may be placed in utmp and wtmp */ domain = NULL; if (gethostname(localhost, sizeof(localhost)) < 0) syslog(LOG_ERR, "couldn't get local hostname: %m"); else domain = strchr(localhost, '.'); if (domain) { domain++; if (*domain && strchr(domain, '.') == NULL) domain = localhost; } fflag = hflag = pflag = 0; uid = getuid(); while ((ch = getopt(argc, argv, "fh:u:p")) != -1) switch (ch) { case 'f': fflag = 1; break; case 'h': if (uid) errx(1, "-h option: %s", strerror(EPERM)); hflag = 1; if (domain && (p = strchr(optarg, '.')) && strcasecmp(p+1, domain) == 0) *p = 0; hostname = optarg; break; case 'p': pflag = 1; break; case 'u': if (uid) errx(1, "-u option: %s", strerror(EPERM)); uflag = 1; rusername = optarg; break; case '?': default: if (!uid) syslog(LOG_ERR, "invalid flag %c", ch); (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); exit(1); } argc -= optind; argv += optind; if (*argv) { username = *argv; ask = 0; } else ask = 1; for (cnt = getdtablesize(); cnt > 2; cnt--) (void)close(cnt); ttyn = ttyname(STDIN_FILENO); if (ttyn == NULL || *ttyn == '\0') { (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); ttyn = tname; } if ((tty = strrchr(ttyn, '/'))) ++tty; else tty = ttyn; for (cnt = 0;; ask = 1) { #if defined(KERBEROS) || defined(KERBEROS5) kdestroy(); #endif if (ask) { fflag = 0; getloginname(); } rootlogin = 0; #if defined(KERBEROS) || defined(KERBEROS5) /* * Why should anyone with a root instance be able * to be root here? */ instance = ""; #endif #ifdef KERBEROS if ((instance = strchr(username, '.')) != NULL) { if (strncmp(instance, ".root", 5) == 0) rootlogin = 1; *instance++ = '\0'; } else instance = ""; #endif #ifdef KERBEROS5 if ((instance = strchr(username, '/')) != NULL) { if (strncmp(instance, "/root", 5) == 0) rootlogin = 1; *instance++ = '\0'; } else instance = ""; #endif if (strlen(username) > UT_NAMESIZE) username[UT_NAMESIZE] = '\0'; /* * Note if trying multiple user names; log failures for * previous user name, but don't bother logging one failure * for nonexistent name (mistyped username). */ if (failures && strcmp(tbuf, username)) { if (failures > (pwd ? 0 : 1)) badlogin(tbuf); failures = 0; } (void)strncpy(tbuf, username, sizeof tbuf-1); tbuf[sizeof tbuf-1] = '\0'; if ((pwd = getpwnam(username))) salt = pwd->pw_passwd; else salt = "xx"; /* * if we have a valid account name, and it doesn't have a * password, or the -f option was specified and the caller * is root or the caller isn't changing their uid, don't * authenticate. */ if (pwd) { if (pwd->pw_uid == 0) rootlogin = 1; if (fflag && (uid == 0 || uid == pwd->pw_uid)) { /* already authenticated */ break; } else if (pwd->pw_passwd[0] == '\0') { /* pretend password okay */ rval = 0; goto ttycheck; } } fflag = 0; (void)setpriority(PRIO_PROCESS, 0, -4); p = getpass("Password:"); if (pwd) { #if defined(KERBEROS) || defined(KERBEROS5) rval = klogin(pwd, instance, localhost, p); if (rval != 0 && rootlogin && pwd->pw_uid != 0) rootlogin = 0; if (rval == 0) authok = 1; else if (rval == 1) { if (pwd->pw_uid != 0) rootlogin = 0; rval = pwcheck(username, p, salt, pwd->pw_passwd); } #else rval = pwcheck(username, p, salt, pwd->pw_passwd); #endif } else { #ifdef SKEY if (strcasecmp(p, "s/key") == 0) (void)skey_authenticate(username); else #endif { useconds_t us; /* * Sleep between 1 and 3 seconds * to emulate a crypt. */ us = arc4random() % 3000000; usleep(us); } rval = 1; } memset(p, 0, strlen(p)); (void)setpriority(PRIO_PROCESS, 0, 0); ttycheck: /* * If trying to log in as root without Kerberos, * but with insecure terminal, refuse the login attempt. */ #if defined(KERBEROS) || defined(KERBEROS5) if (authok == 0) #endif if (pwd && !rval && rootlogin && !rootterm(tty)) { (void)fprintf(stderr, "%s login refused on this terminal.\n", pwd->pw_name); if (hostname) syslog(LOG_NOTICE, "LOGIN %s REFUSED FROM %s%s%s ON TTY %s", pwd->pw_name, rusername ? rusername : "", rusername ? "@" : "", hostname, tty); else syslog(LOG_NOTICE, "LOGIN %s REFUSED ON TTY %s", pwd->pw_name, tty); continue; } if (pwd && !rval) break; (void)printf("Login incorrect\n"); failures++; if (pwd) log_failedlogin(pwd->pw_uid, hostname, rusername, tty); /* we allow 10 tries, but after 3 we start backing off */ if (++cnt > 3) { if (cnt >= 10) { badlogin(username); sleepexit(1); } sleep((u_int)((cnt - 3) * 5)); } } /* committed to login -- turn off timeout */ (void)alarm((u_int)0); endpwent(); /* if user not super-user, check for disabled logins */ if (!rootlogin) checknologin(); setegid(pwd->pw_gid); seteuid(pwd->pw_uid); if (chdir(pwd->pw_dir) < 0) { (void)printf("No home directory %s!\n", pwd->pw_dir); if (chdir("/")) exit(0); pwd->pw_dir = "/"; (void)printf("Logging in with home = \"/\".\n"); } quietlog = ((strcmp(pwd->pw_shell, "/sbin/nologin") == 0) || (access(_PATH_HUSHLOGIN, F_OK) == 0)); seteuid(0); setegid(0); /* XXX use a saved gid instead? */ if (pwd->pw_change || pwd->pw_expire) (void)gettimeofday(&tp, (struct timezone *)NULL); if (pwd->pw_change) { if (tp.tv_sec >= pwd->pw_change) { (void)printf("Sorry -- your password has expired.\n"); sleepexit(1); } else if (pwd->pw_change - tp.tv_sec < 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) (void)printf("Warning: your password expires on %s", ctime(&pwd->pw_change)); } if (pwd->pw_expire) { if (tp.tv_sec >= pwd->pw_expire) { (void)printf("Sorry -- your account has expired.\n"); sleepexit(1); } else if (pwd->pw_expire - tp.tv_sec < 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) (void)printf("Warning: your account expires on %s", ctime(&pwd->pw_expire)); } /* Nothing else left to fail -- really log in. */ (void)signal(SIGHUP, SIG_DFL); memset((void *)&utmp, 0, sizeof(utmp)); (void)time(&utmp.ut_time); (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); if (hostname) (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); login(&utmp); if (!quietlog) (void)check_failedlogin(pwd->pw_uid); dolastlog(quietlog); login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); (void)chown(ttyn, pwd->pw_uid, (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); #if defined(KERBEROS) || defined(KERBEROS5) /* Fork so that we can call kdestroy */ if (krbtkfile_env) dofork(); #endif (void)setegid(pwd->pw_gid); (void)setgid(pwd->pw_gid); initgroups(username, pwd->pw_gid); if (*pwd->pw_shell == '\0') pwd->pw_shell = _PATH_BSHELL; /* Destroy environment unless user has requested its preservation. */ if (!pflag) { if ((environ = calloc(1, sizeof (char *))) == NULL) err(1, "calloc"); } else { char **cpp, **cpp2; for (cpp2 = cpp = environ; *cpp; cpp++) { if (strncmp(*cpp, "LD_", 3) && strncmp(*cpp, "IFS=", 4)) *cpp2++ = *cpp; } *cpp2 = 0; } (void)setenv("HOME", pwd->pw_dir, 1); (void)setenv("SHELL", pwd->pw_shell, 1); if (term[0] == '\0') (void)strncpy(term, stypeof(tty), sizeof(term)); (void)setenv("TERM", term, 0); (void)setenv("LOGNAME", pwd->pw_name, 1); (void)setenv("USER", pwd->pw_name, 1); (void)setenv("PATH", _PATH_DEFPATH, 0); if (hostname) (void)setenv("REMOTEHOST", hostname, 1); if (rusername) (void)setenv("REMOTEUSER", rusername, 1); #ifdef KERBEROS if (krbtkfile_env) (void)setenv("KRBTKFILE", krbtkfile_env, 1); #endif #ifdef KERBEROS5 if (krbtkfile_env) (void)setenv("KRB5CCNAME", krbtkfile_env, 1); #endif /* If fflag is on, assume caller/authenticator has logged root login. */ if (rootlogin && fflag == 0) { if (hostname) syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s%s%s", username, tty, rusername ? rusername : "", rusername ? "@" : "", hostname); else syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); } #if defined(KERBEROS) || defined(KERBEROS5) if (!quietlog && notickets == 1) (void)printf("Warning: no Kerberos tickets issued.\n"); #endif if (!quietlog) { #if 0 (void)printf("%s\n\t%s %s\n\n", "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", "The Regents of the University of California. ", "All rights reserved."); #endif motd(); (void)snprintf(tbuf, sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); if (stat(tbuf, &st) == 0 && st.st_size != 0) (void)printf("You have %smail.\n", (st.st_mtime > st.st_atime) ? "new " : ""); } (void)signal(SIGALRM, SIG_DFL); (void)signal(SIGQUIT, SIG_DFL); (void)signal(SIGINT, SIG_DFL); (void)signal(SIGTSTP, SIG_IGN); tbuf[0] = '-'; (void)strncpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? p + 1 : pwd->pw_shell, sizeof tbuf - 1 - 1); tbuf[sizeof tbuf - 1] = '\0'; if (setlogin(pwd->pw_name) < 0) syslog(LOG_ERR, "setlogin() failure: %m"); /* Discard permissions last so can't get killed and drop core. */ if (rootlogin) (void) setuid(0); else { (void) seteuid(pwd->pw_uid); (void) setuid(pwd->pw_uid); } #ifdef KERBEROS kgettokens(pwd->pw_dir); #endif execlp(pwd->pw_shell, tbuf, 0); err(1, "%s", pwd->pw_shell); } int pwcheck(user, p, salt, passwd) char *user, *p, *salt, *passwd; { #ifdef SKEY if (strcasecmp(p, "s/key") == 0) return skey_authenticate(user); #endif return strcmp(crypt(p, salt), passwd); } #if defined(KERBEROS) || defined(KERBEROS5) #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ #else #define NBUFSIZ (UT_NAMESIZE + 1) #endif #if defined(KERBEROS) || defined(KERBEROS5) /* * This routine handles cleanup stuff, and the like. * It exists only in the child process. */ #include void dofork() { int child; if (!(child = fork())) return; /* Child process */ /* Setup stuff? This would be things we could do in parallel with login */ (void) chdir("/"); /* Let's not keep the fs busy... */ /* If we're the parent, watch the child until it dies */ while (wait(0) != child) ; /* Cleanup stuff */ /* Run kdestroy to destroy tickets */ kdestroy(); /* Leave */ exit(0); } #endif void getloginname() { int ch; char *p; static char nbuf[NBUFSIZ]; for (;;) { (void)printf("login: "); for (p = nbuf; (ch = getchar()) != '\n'; ) { if (ch == EOF) { badlogin(username); exit(0); } if (p < nbuf + (NBUFSIZ - 1)) *p++ = ch; } if (p > nbuf) { if (nbuf[0] == '-') (void)fprintf(stderr, "login names may not start with '-'.\n"); else { *p = '\0'; username = nbuf; break; } } } } int rootterm(ttyn) char *ttyn; { struct ttyent *t; return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); } jmp_buf motdinterrupt; void motd() { int fd, nchars; sig_t oldint; char tbuf[8192]; if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) return; oldint = signal(SIGINT, sigint); if (setjmp(motdinterrupt) == 0) while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) (void)write(fileno(stdout), tbuf, nchars); (void)signal(SIGINT, oldint); (void)close(fd); } /* ARGSUSED */ void sigint(signo) int signo; { longjmp(motdinterrupt, 1); } /* ARGSUSED */ void timedout(signo) int signo; { (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); exit(0); } void checknologin() { int fd, nchars; char tbuf[8192]; if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) (void)write(fileno(stdout), tbuf, nchars); sleepexit(0); } } void dolastlog(quiet) int quiet; { struct lastlog ll; int fd; if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), SEEK_SET); if (!quiet) { if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && ll.ll_time != 0) { (void)printf("Last login: %.*s ", 24-5, (char *)ctime(&ll.ll_time)); (void)printf("on %.*s", (int)sizeof(ll.ll_line), ll.ll_line); if (*ll.ll_host != '\0') (void)printf(" from %.*s", (int)sizeof(ll.ll_host), ll.ll_host); (void)putchar('\n'); } (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), SEEK_SET); } memset((void *)&ll, 0, sizeof(ll)); (void)time(&ll.ll_time); (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); if (hostname) (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); (void)write(fd, (char *)&ll, sizeof(ll)); (void)close(fd); } } void badlogin(name) char *name; { if (failures == 0) return; if (hostname) { syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s%s%s", failures, failures > 1 ? "S" : "", rusername ? rusername : "", rusername ? "@" : "", hostname); syslog(LOG_AUTHPRIV|LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s%s%s, %s", failures, failures > 1 ? "S" : "", rusername ? rusername : "", rusername ? "@" : "", hostname, name); } else { syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", failures, failures > 1 ? "S" : "", tty); syslog(LOG_AUTHPRIV|LOG_NOTICE, "%d LOGIN FAILURE%s ON %s, %s", failures, failures > 1 ? "S" : "", tty, name); } } #undef UNKNOWN #define UNKNOWN "su" char * stypeof(ttyid) char *ttyid; { struct ttyent *t; return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); } void sleepexit(eval) int eval; { (void)sleep(5); exit(eval); } void sighup(signum) int signum; { if (username) badlogin(username); exit(W_EXITCODE(0, signum)); }