diff options
Diffstat (limited to 'usr.bin/login/login.c')
-rw-r--r-- | usr.bin/login/login.c | 594 |
1 files changed, 594 insertions, 0 deletions
diff --git a/usr.bin/login/login.c b/usr.bin/login/login.c new file mode 100644 index 0000000..ef75733 --- /dev/null +++ b/usr.bin/login/login.c @@ -0,0 +1,594 @@ +/*- + * 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 +static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; +#endif /* not lint */ + +/* + * login [ name ] + * login -h hostname (for telnetd, etc.) + * login -f name (for pre-authenticated login: datakit, xterm, etc.) + */ + +#include <sys/param.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <sys/resource.h> +#include <sys/file.h> + +#include <err.h> +#include <errno.h> +#include <grp.h> +#include <pwd.h> +#include <setjmp.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> +#include <ttyent.h> +#include <tzfile.h> +#include <unistd.h> +#include <utmp.h> + +#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 sleepexit __P((int)); +char *stypeof __P((char *)); +void timedout __P((int)); +#ifdef KERBEROS +int klogin __P((struct passwd *, char *, char *, char *)); +#endif + +extern void login __P((struct utmp *)); + +#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; + +#ifdef KERBEROS +int notickets = 1; +char *instance; +char *krbtkfile_env; +int authok; +#endif + +struct passwd *pwd; +int failures; +char term[64], *envinit[1], *hostname, *username, *tty; + +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, 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)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, '.'); + + fflag = hflag = pflag = 0; + uid = getuid(); + while ((ch = getopt(argc, argv, "fh:p")) != EOF) + 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, domain) == 0) + *p = 0; + hostname = optarg; + break; + case 'p': + pflag = 1; + 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 (ask) { + fflag = 0; + getloginname(); + } + rootlogin = 0; +#ifdef KERBEROS + 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)strcpy(tbuf, username); + + 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 && (*pwd->pw_passwd == '\0' || + fflag && (uid == 0 || uid == pwd->pw_uid))) + break; + fflag = 0; + if (pwd && pwd->pw_uid == 0) + rootlogin = 1; + + (void)setpriority(PRIO_PROCESS, 0, -4); + + p = getpass("Password:"); + + if (pwd) { +#ifdef KERBEROS + 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) + rval = strcmp(crypt(p, salt), pwd->pw_passwd); +#else + rval = strcmp(crypt(p, salt), pwd->pw_passwd); +#endif + } + memset(p, 0, strlen(p)); + + (void)setpriority(PRIO_PROCESS, 0, 0); + + /* + * If trying to log in as root without Kerberos, + * but with insecure terminal, refuse the login attempt. + */ +#ifdef KERBEROS + if (authok == 0) +#endif + if (pwd && 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 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\n"); + failures++; + /* 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(); + + 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 = access(_PATH_HUSHLOGIN, F_OK) == 0; + + 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. */ + 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); + + dolastlog(quietlog); + + (void)chown(ttyn, pwd->pw_uid, + (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : 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) + environ = envinit; + (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); +#ifdef KERBEROS + if (krbtkfile_env) + (void)setenv("KRBTKFILE", krbtkfile_env, 1); +#endif + + if (tty[sizeof("tty")-1] == 'd') + syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); + + /* 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); + +#ifdef KERBEROS + if (!quietlog && notickets == 1) + (void)printf("Warning: no Kerberos tickets issued.\n"); +#endif + + if (!quietlog) { + (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."); + 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)strcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? + p + 1 : pwd->pw_shell); + + 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) setuid(pwd->pw_uid); + + execlp(pwd->pw_shell, tbuf, 0); + err(1, "%s", pwd->pw_shell); +} + +#ifdef KERBEROS +#define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ +#else +#define NBUFSIZ (UT_NAMESIZE + 1) +#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), L_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)); + if (*ll.ll_host != '\0') + (void)printf("from %.*s\n", + (int)sizeof(ll.ll_host), + ll.ll_host); + else + (void)printf("on %.*s\n", + (int)sizeof(ll.ll_line), + ll.ll_line); + } + (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_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", + failures, failures > 1 ? "S" : "", hostname); + syslog(LOG_AUTHPRIV|LOG_NOTICE, + "%d LOGIN FAILURE%s FROM %s, %s", + failures, failures > 1 ? "S" : "", 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); +} |