/* $NetBSD: login.c,v 1.105 2014/11/12 22:23:38 aymeric 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. 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. */ #include #ifndef lint __COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\ The Regents of the University of California. All rights reserved."); #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; #endif __RCSID("$NetBSD: login.c,v 1.105 2014/11/12 22:23:38 aymeric 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 #ifdef SUPPORT_UTMP #include #endif #ifdef SUPPORT_UTMPX #include #endif #include #ifdef SKEY #include #endif #ifdef KERBEROS5 #include #include #endif #ifdef LOGIN_CAP #include #endif #include #include "pathnames.h" #include "common.h" #ifdef KERBEROS5 int login_krb5_forwardable_tgt = 0; static int login_krb5_get_tickets = 1; static int login_krb5_retain_ccache = 0; #endif static void checknologin(char *); #ifdef KERBEROS5 int k5login(struct passwd *, char *, char *, char *); void k5destroy(void); int k5_read_creds(const char *); int k5_write_creds(void); #endif #if defined(KERBEROS5) static void dofork(void); #endif static void usage(void) __attribute__((__noreturn__)); #define TTYGRPNAME "tty" /* name of group to own ttys */ #define DEFAULT_BACKOFF 3 #define DEFAULT_RETRIES 10 #if defined(KERBEROS5) int has_ccache = 0; int notickets = 1; extern krb5_context kcontext; extern int have_forward; static char *instance; extern char *krb5tkfile_env; extern int krb5_configured; #endif #if defined(KERBEROS5) #define KERBEROS_CONFIGURED krb5_configured #endif extern char **environ; int main(int argc, char *argv[]) { struct group *gr; struct stat st; int ask, ch, cnt, fflag, hflag, pflag, sflag, quietlog, rootlogin, rval; uid_t uid, saved_uid; gid_t saved_gid, saved_gids[NGROUPS_MAX]; int nsaved_gids; #ifdef notdef char *domain; #endif char *p, *ttyn; const char *pwprompt; char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; char localhost[MAXHOSTNAMELEN + 1]; int need_chpass, require_chpass; int login_retries = DEFAULT_RETRIES, login_backoff = DEFAULT_BACKOFF; time_t pw_warntime = _PASSWORD_WARNDAYS * SECSPERDAY; char *loginname = NULL; #ifdef KERBEROS5 int Fflag; krb5_error_code kerror; #endif #if defined(KERBEROS5) int got_tickets = 0; #endif #ifdef LOGIN_CAP char *shell = NULL; login_cap_t *lc = NULL; #endif tbuf[0] = '\0'; rval = 0; pwprompt = NULL; nested = NULL; need_chpass = require_chpass = 0; (void)signal(SIGALRM, timedout); (void)alarm(timeout); (void)signal(SIGQUIT, SIG_IGN); (void)signal(SIGINT, SIG_IGN); (void)setpriority(PRIO_PROCESS, 0, 0); openlog("login", 0, 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/utmpx and wtmp/wtmpx * -a in addition to -h, a server may supply -a to pass the actual * server address. * -s is used to force use of S/Key or equivalent. */ if (gethostname(localhost, sizeof(localhost)) < 0) { syslog(LOG_ERR, "couldn't get local hostname: %m"); strcpy(hostname, "amnesiac"); } #ifdef notdef domain = strchr(localhost, '.'); #endif localhost[sizeof(localhost) - 1] = '\0'; fflag = hflag = pflag = sflag = 0; have_ss = 0; #ifdef KERBEROS5 Fflag = 0; have_forward = 0; #endif uid = getuid(); while ((ch = getopt(argc, argv, "a:Ffh:ps")) != -1) switch (ch) { case 'a': if (uid) errx(EXIT_FAILURE, "-a option: %s", strerror(EPERM)); decode_ss(optarg); #ifdef notdef (void)sockaddr_snprintf(optarg, sizeof(struct sockaddr_storage), "%a", (void *)&ss); #endif break; case 'F': #ifdef KERBEROS5 Fflag = 1; #endif /* FALLTHROUGH */ case 'f': fflag = 1; break; case 'h': if (uid) errx(EXIT_FAILURE, "-h option: %s", strerror(EPERM)); hflag = 1; #ifdef notdef if (domain && (p = strchr(optarg, '.')) != NULL && strcasecmp(p, domain) == 0) *p = '\0'; #endif hostname = optarg; break; case 'p': pflag = 1; break; case 's': sflag = 1; break; default: case '?': usage(); break; } setproctitle(NULL); argc -= optind; argv += optind; if (*argv) { username = loginname = *argv; ask = 0; } else ask = 1; #ifdef F_CLOSEM (void)fcntl(3, F_CLOSEM, 0); #else for (cnt = getdtablesize(); cnt > 2; cnt--) (void)close(cnt); #endif ttyn = ttyname(STDIN_FILENO); if (ttyn == NULL || *ttyn == '\0') { (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); ttyn = tname; } if ((tty = strstr(ttyn, "/pts/")) != NULL) ++tty; else if ((tty = strrchr(ttyn, '/')) != NULL) ++tty; else tty = ttyn; if (issetugid()) { nested = strdup(user_from_uid(getuid(), 0)); if (nested == NULL) { syslog(LOG_ERR, "strdup: %m"); sleepexit(EXIT_FAILURE); } } #ifdef LOGIN_CAP /* Get "login-retries" and "login-backoff" from default class */ if ((lc = login_getclass(NULL)) != NULL) { login_retries = (int)login_getcapnum(lc, "login-retries", DEFAULT_RETRIES, DEFAULT_RETRIES); login_backoff = (int)login_getcapnum(lc, "login-backoff", DEFAULT_BACKOFF, DEFAULT_BACKOFF); login_close(lc); lc = NULL; } #endif #ifdef KERBEROS5 kerror = krb5_init_context(&kcontext); if (kerror) { /* * If Kerberos is not configured, that is, we are * not using Kerberos, do not log the error message. * However, if Kerberos is configured, and the * context init fails for some other reason, we need * to issue a no tickets warning to the user when the * login succeeds. */ if (kerror != ENXIO) { /* XXX NetBSD-local Heimdal hack */ syslog(LOG_NOTICE, "%s when initializing Kerberos context", error_message(kerror)); krb5_configured = 1; } login_krb5_get_tickets = 0; } #endif /* KERBEROS5 */ for (cnt = 0;; ask = 1) { #if defined(KERBEROS5) if (login_krb5_get_tickets) k5destroy(); #endif if (ask) { fflag = 0; loginname = getloginname(); } rootlogin = 0; #ifdef KERBEROS5 if ((instance = strchr(loginname, '/')) != NULL) *instance++ = '\0'; else instance = __UNCONST(""); #endif username = trimloginname(loginname); /* * 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)strlcpy(tbuf, username, sizeof(tbuf)); pwd = getpwnam(username); #ifdef LOGIN_CAP /* * Establish the class now, before we might goto * within the next block. pwd can be NULL since it * falls back to the "default" class if it is. */ lc = login_getclass(pwd ? pwd->pw_class : NULL); #endif /* * 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 */ #ifdef KERBEROS5 if (login_krb5_get_tickets && Fflag) k5_read_creds(username); #endif break; } else if (pwd->pw_passwd[0] == '\0') { /* pretend password okay */ rval = 0; goto ttycheck; } } fflag = 0; (void)setpriority(PRIO_PROCESS, 0, -4); #ifdef SKEY if (skey_haskey(username) == 0) { static char skprompt[80]; const char *skinfo = skey_keyinfo(username); (void)snprintf(skprompt, sizeof(skprompt), "Password [ %s ]:", skinfo ? skinfo : "error getting challenge"); pwprompt = skprompt; } else #endif pwprompt = "Password:"; p = getpass(pwprompt); if (pwd == NULL) { rval = 1; goto skip; } #ifdef KERBEROS5 if (login_krb5_get_tickets && k5login(pwd, instance, localhost, p) == 0) { rval = 0; got_tickets = 1; } #endif #if defined(KERBEROS5) if (got_tickets) goto skip; #endif #ifdef SKEY if (skey_haskey(username) == 0 && skey_passcheck(username, p) != -1) { rval = 0; goto skip; } #endif if (!sflag && *pwd->pw_passwd != '\0' && !strcmp(crypt(p, pwd->pw_passwd), pwd->pw_passwd)) { rval = 0; require_chpass = 1; goto skip; } rval = 1; skip: 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 (pwd && !rval && rootlogin && !rootterm(tty)) { (void)printf("Login incorrect or refused on this " "terminal.\n"); if (hostname) syslog(LOG_NOTICE, "LOGIN %s REFUSED FROM %s ON TTY %s", pwd->pw_name, 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 or refused on this " "terminal.\n"); failures++; cnt++; /* * We allow login_retries tries, but after login_backoff * we start backing off. These default to 10 and 3 * respectively. */ if (cnt > login_backoff) { if (cnt >= login_retries) { badlogin(username); sleepexit(EXIT_FAILURE); } sleep((u_int)((cnt - login_backoff) * 5)); } } /* committed to login -- turn off timeout */ (void)alarm((u_int)0); endpwent(); /* if user not super-user, check for disabled logins */ #ifdef LOGIN_CAP if (!login_getcapbool(lc, "ignorenologin", rootlogin)) checknologin(login_getcapstr(lc, "nologin", NULL, NULL)); #else if (!rootlogin) checknologin(NULL); #endif #ifdef LOGIN_CAP quietlog = login_getcapbool(lc, "hushlogin", 0); #else quietlog = 0; #endif /* Temporarily give up special privileges so we can change */ /* into NFS-mounted homes that are exported for non-root */ /* access and have mode 7x0 */ saved_uid = geteuid(); saved_gid = getegid(); nsaved_gids = getgroups(NGROUPS_MAX, saved_gids); (void)setegid(pwd->pw_gid); initgroups(username, pwd->pw_gid); (void)seteuid(pwd->pw_uid); if (chdir(pwd->pw_dir) < 0) { #ifdef LOGIN_CAP if (login_getcapbool(lc, "requirehome", 0)) { (void)printf("Home directory %s required\n", pwd->pw_dir); sleepexit(EXIT_FAILURE); } #endif (void)printf("No home directory %s!\n", pwd->pw_dir); if (chdir("/") == -1) exit(EXIT_FAILURE); pwd->pw_dir = __UNCONST("/"); (void)printf("Logging in with home = \"/\".\n"); } if (!quietlog) quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; /* regain special privileges */ (void)seteuid(saved_uid); setgroups(nsaved_gids, saved_gids); (void)setegid(saved_gid); #ifdef LOGIN_CAP pw_warntime = login_getcaptime(lc, "password-warn", _PASSWORD_WARNDAYS * SECSPERDAY, _PASSWORD_WARNDAYS * SECSPERDAY); #endif (void)gettimeofday(&now, NULL); if (pwd->pw_expire) { if (now.tv_sec >= pwd->pw_expire) { (void)printf("Sorry -- your account has expired.\n"); sleepexit(EXIT_FAILURE); } else if (pwd->pw_expire - now.tv_sec < pw_warntime && !quietlog) (void)printf("Warning: your account expires on %s", ctime(&pwd->pw_expire)); } if (pwd->pw_change) { if (pwd->pw_change == _PASSWORD_CHGNOW) need_chpass = 1; else if (now.tv_sec >= pwd->pw_change) { (void)printf("Sorry -- your password has expired.\n"); sleepexit(EXIT_FAILURE); } else if (pwd->pw_change - now.tv_sec < pw_warntime && !quietlog) (void)printf("Warning: your password expires on %s", ctime(&pwd->pw_change)); } /* Nothing else left to fail -- really log in. */ update_db(quietlog, rootlogin, fflag); (void)chown(ttyn, pwd->pw_uid, (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); if (ttyaction(ttyn, "login", pwd->pw_name)) (void)printf("Warning: ttyaction failed.\n"); #if defined(KERBEROS5) /* Fork so that we can call kdestroy */ if (! login_krb5_retain_ccache && has_ccache) dofork(); #endif /* Destroy environment unless user has requested its preservation. */ if (!pflag) environ = envinit; #ifdef LOGIN_CAP if (nested == NULL && setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETLOGIN) != 0) { syslog(LOG_ERR, "setusercontext failed"); exit(EXIT_FAILURE); } if (setusercontext(lc, pwd, pwd->pw_uid, (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETLOGIN))) != 0) { syslog(LOG_ERR, "setusercontext failed"); exit(EXIT_FAILURE); } #else (void)setgid(pwd->pw_gid); initgroups(username, pwd->pw_gid); if (nested == NULL && 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)setuid(pwd->pw_uid); #endif if (*pwd->pw_shell == '\0') pwd->pw_shell = __UNCONST(_PATH_BSHELL); #ifdef LOGIN_CAP if ((shell = login_getcapstr(lc, "shell", NULL, NULL)) != NULL) { if ((shell = strdup(shell)) == NULL) { syslog(LOG_ERR, "Cannot alloc mem"); sleepexit(EXIT_FAILURE); } pwd->pw_shell = shell; } #endif (void)setenv("HOME", pwd->pw_dir, 1); (void)setenv("SHELL", pwd->pw_shell, 1); if (term[0] == '\0') { const char *tt = stypeof(tty); #ifdef LOGIN_CAP if (tt == NULL) tt = login_getcapstr(lc, "term", NULL, NULL); #endif /* unknown term -> "su" */ (void)strlcpy(term, tt != NULL ? tt : "su", sizeof(term)); } (void)setenv("TERM", term, 0); (void)setenv("LOGNAME", pwd->pw_name, 1); (void)setenv("USER", pwd->pw_name, 1); #ifdef LOGIN_CAP setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETPATH); #else (void)setenv("PATH", _PATH_DEFPATH, 0); #endif #ifdef KERBEROS5 if (krb5tkfile_env) (void)setenv("KRB5CCNAME", krb5tkfile_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", username, tty, hostname); else syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); } #if defined(KERBEROS5) if (KERBEROS_CONFIGURED && !quietlog && notickets == 1) (void)printf("Warning: no Kerberos tickets issued.\n"); #endif if (!quietlog) { const char *fname; #ifdef LOGIN_CAP fname = login_getcapstr(lc, "copyright", NULL, NULL); if (fname != NULL && access(fname, F_OK) == 0) motd(fname); else #endif (void)printf("%s", copyrightstr); #ifdef LOGIN_CAP fname = login_getcapstr(lc, "welcome", NULL, NULL); if (fname == NULL || access(fname, F_OK) != 0) #endif fname = _PATH_MOTDFILE; motd(fname); (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 " : ""); } #ifdef LOGIN_CAP login_close(lc); #endif (void)signal(SIGALRM, SIG_DFL); (void)signal(SIGQUIT, SIG_DFL); (void)signal(SIGINT, SIG_DFL); (void)signal(SIGTSTP, SIG_IGN); tbuf[0] = '-'; (void)strlcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? p + 1 : pwd->pw_shell, sizeof(tbuf) - 1); /* Wait to change password until we're unprivileged */ if (need_chpass) { if (!require_chpass) (void)printf( "Warning: your password has expired. Please change it as soon as possible.\n"); else { int status; (void)printf( "Your password has expired. Please choose a new one.\n"); switch (fork()) { case -1: warn("fork"); sleepexit(EXIT_FAILURE); case 0: execl(_PATH_BINPASSWD, "passwd", NULL); _exit(EXIT_FAILURE); default: if (wait(&status) == -1 || WEXITSTATUS(status)) sleepexit(EXIT_FAILURE); } } } #ifdef KERBEROS5 if (login_krb5_get_tickets) k5_write_creds(); #endif execlp(pwd->pw_shell, tbuf, NULL); err(EXIT_FAILURE, "%s", pwd->pw_shell); } #if defined(KERBEROS5) /* * This routine handles cleanup stuff, and the like. * It exists only in the child process. */ static void dofork(void) { pid_t child, wchild; switch (child = fork()) { case 0: return; /* Child process */ case -1: err(EXIT_FAILURE, "Can't fork"); /*NOTREACHED*/ default: break; } /* * Setup stuff? This would be things we could do in parallel * with login */ if (chdir("/") == -1) /* Let's not keep the fs busy... */ err(EXIT_FAILURE, "Can't chdir to `/'"); /* If we're the parent, watch the child until it dies */ while ((wchild = wait(NULL)) != child) if (wchild == -1) err(EXIT_FAILURE, "Can't wait"); /* Cleanup stuff */ /* Run kdestroy to destroy tickets */ if (login_krb5_get_tickets) k5destroy(); /* Leave */ exit(EXIT_SUCCESS); } #endif static void checknologin(char *fname) { int fd, nchars; char tbuf[8192]; if ((fd = open(fname ? fname : _PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) (void)write(fileno(stdout), tbuf, nchars); sleepexit(EXIT_SUCCESS); } } static void usage(void) { (void)fprintf(stderr, "Usage: %s [-Ffps] [-a address] [-h hostname] [username]\n", getprogname()); exit(EXIT_FAILURE); }