int
main(int argc, char **argv)
{
struct group *gr;
struct stat st;
int retries, backoff;
int ask, ch, cnt, quietlog, rootlogin, rval;
uid_t uid, euid;
gid_t egid;
char *term;
char *p, *ttyn;
char tname[sizeof(_PATH_TTY) + 10];
char *arg0;
const char *tp;
const char *shell = NULL;
login_cap_t *lc = NULL;
login_cap_t *lc_user = NULL;
pid_t pid;
#ifdef USE_BSM_AUDIT
char auditsuccess = 1;
#endif
signal(SIGQUIT, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGHUP, SIG_IGN);
if (setjmp(timeout_buf)) {
if (failures)
badlogin(username);
fprintf(stderr, "Login timed out after %d seconds\n",
timeout);
bail(NO_SLEEP_EXIT, 0);
}
signal(SIGALRM, timedout);
alarm(timeout);
setpriority(PRIO_PROCESS, 0, 0);
openlog("login", LOG_ODELAY, LOG_AUTH);
uid = getuid();
euid = geteuid();
egid = getegid();
while ((ch = getopt(argc, argv, "fh:p")) != -1)
switch (ch) {
case 'f':
fflag = 1;
break;
case 'h':
if (uid != 0)
errx(1, "-h option: %s", strerror(EPERM));
if (strlen(optarg) >= MAXHOSTNAMELEN)
errx(1, "-h option: %s: exceeds maximum "
"hostname size", optarg);
hflag = 1;
hostname = optarg;
break;
case 'p':
pflag = 1;
break;
case '?':
default:
if (uid == 0)
syslog(LOG_ERR, "invalid flag %c", ch);
usage();
}
argc -= optind;
argv += optind;
if (argc > 0) {
username = strdup(*argv);
if (username == NULL)
err(1, "strdup()");
ask = 0;
} else {
ask = 1;
}
setproctitle("-%s", getprogname());
for (cnt = getdtablesize(); cnt > 2; cnt--)
close(cnt);
/*
* Get current TTY
*/
ttyn = ttyname(STDIN_FILENO);
if (ttyn == NULL || *ttyn == '\0') {
snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
ttyn = tname;
}
if (strncmp(ttyn, _PATH_DEV, sizeof(_PATH_DEV) -1) == 0)
tty = ttyn + sizeof(_PATH_DEV) -1;
else
tty = ttyn;
/*
* Get "login-retries" & "login-backoff" from default class
*/
lc = login_getclass(NULL);
prompt = login_getcapstr(lc, "login_prompt",
default_prompt, default_prompt);
passwd_prompt = login_getcapstr(lc, "passwd_prompt",
default_passwd_prompt, default_passwd_prompt);
retries = login_getcapnum(lc, "login-retries",
DEFAULT_RETRIES, DEFAULT_RETRIES);
backoff = login_getcapnum(lc, "login-backoff",
DEFAULT_BACKOFF, DEFAULT_BACKOFF);
login_close(lc);
lc = NULL;
/*
* Try to authenticate the user until we succeed or time out.
*/
for (cnt = 0;; ask = 1) {
if (ask) {
fflag = 0;
if (olduser != NULL)
free(olduser);
olduser = username;
username = getloginname();
}
rootlogin = 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(olduser, username) != 0) {
if (failures > (pwd ? 0 : 1))
badlogin(olduser);
}
/*
* Load the PAM policy and set some variables
*/
pam_err = pam_start("login", username, &pamc, &pamh);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_start()");
#ifdef USE_BSM_AUDIT
au_login_fail("PAM Error", 1);
#endif
bail(NO_SLEEP_EXIT, 1);
}
pam_err = pam_set_item(pamh, PAM_TTY, tty);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_set_item(PAM_TTY)");
#ifdef USE_BSM_AUDIT
au_login_fail("PAM Error", 1);
#endif
bail(NO_SLEEP_EXIT, 1);
}
pam_err = pam_set_item(pamh, PAM_RHOST, hostname);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_set_item(PAM_RHOST)");
#ifdef USE_BSM_AUDIT
au_login_fail("PAM Error", 1);
#endif
bail(NO_SLEEP_EXIT, 1);
}
pwd = getpwnam(username);
if (pwd != NULL && pwd->pw_uid == 0)
rootlogin = 1;
/*
* If the -f option was specified and the caller is
* root or the caller isn't changing their uid, don't
* authenticate.
*/
if (pwd != NULL && fflag &&
(uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) {
/* already authenticated */
rval = 0;
#ifdef USE_BSM_AUDIT
auditsuccess = 0; /* opened a terminal window only */
#endif
} else {
fflag = 0;
setpriority(PRIO_PROCESS, 0, -4);
rval = auth_pam();
setpriority(PRIO_PROCESS, 0, 0);
}
if (pwd && rval == 0)
break;
pam_cleanup();
/*
* We are not exiting here, but this corresponds to a failed
* login event, so set exitstatus to 1.
*/
#ifdef USE_BSM_AUDIT
au_login_fail("Login incorrect", 1);
#endif
printf("Login incorrect\n");
failures++;
pwd = NULL;
/*
* Allow up to 'retry' (10) attempts, but start
* backing off after 'backoff' (3) attempts.
*/
if (++cnt > backoff) {
if (cnt >= retries) {
badlogin(username);
bail(SLEEP_EXIT, 1);
}
sleep((u_int)((cnt - backoff) * 5));
}
}
/* committed to login -- turn off timeout */
alarm((u_int)0);
signal(SIGHUP, SIG_DFL);
endpwent();
#ifdef USE_BSM_AUDIT
/* Audit successful login. */
if (auditsuccess)
au_login_success();
#endif
/*
* Establish the login class.
*/
lc = login_getpwclass(pwd);
lc_user = login_getuserclass(pwd);
if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0)))
quietlog = login_getcapbool(lc, "hushlogin", 0);
/*
* Switching needed for NFS with root access disabled.
*
* XXX: This change fails to modify the additional groups for the
* process, and as such, may restrict rights normally granted
* through those groups.
*/
setegid(pwd->pw_gid);
seteuid(rootlogin ? 0 : pwd->pw_uid);
if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) {
if (login_getcapbool(lc, "requirehome", 0))
refused("Home directory not available", "HOMEDIR", 1);
if (chdir("/") < 0)
refused("Cannot find root directory", "ROOTDIR", 1);
if (!quietlog || *pwd->pw_dir)
printf("No home directory.\nLogging in with home = \"/\".\n");
pwd->pw_dir = strdup("/");
if (pwd->pw_dir == NULL) {
syslog(LOG_NOTICE, "strdup(): %m");
bail(SLEEP_EXIT, 1);
}
}
seteuid(euid);
setegid(egid);
if (!quietlog) {
quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
if (!quietlog)
pam_silent = 0;
}
shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell);
if (*pwd->pw_shell == '\0')
pwd->pw_shell = strdup(_PATH_BSHELL);
if (pwd->pw_shell == NULL) {
syslog(LOG_NOTICE, "strdup(): %m");
bail(SLEEP_EXIT, 1);
}
if (*shell == '\0') /* Not overridden */
shell = pwd->pw_shell;
if ((shell = strdup(shell)) == NULL) {
syslog(LOG_NOTICE, "strdup(): %m");
bail(SLEEP_EXIT, 1);
}
/*
* Set device protections, depending on what terminal the
* user is logged in. This feature is used on Suns to give
* console users better privacy.
*/
login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
/*
* Clear flags of the tty. None should be set, and when the
* user sets them otherwise, this can cause the chown to fail.
* Since it isn't clear that flags are useful on character
* devices, we just clear them.
*
* We don't log in the case of EOPNOTSUPP because dev might be
* on NFS, which doesn't support chflags.
*
* We don't log in the EROFS because that means that /dev is on
* a read only file system and we assume that the permissions there
* are sane.
*/
if (ttyn != tname && chflags(ttyn, 0))
if (errno != EOPNOTSUPP && errno != EROFS)
syslog(LOG_ERR, "chflags(%s): %m", ttyn);
if (ttyn != tname && chown(ttyn, pwd->pw_uid,
(gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid))
if (errno != EROFS)
syslog(LOG_ERR, "chown(%s): %m", ttyn);
/*
* Exclude cons/vt/ptys only, assume dialup otherwise
* TODO: Make dialup tty determination a library call
* for consistency (finger etc.)
*/
if (hflag && isdialuptty(tty))
syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
#ifdef LOGALL
/*
* Syslog each successful login, so we don't have to watch
* hundreds of wtmp or lastlogin files.
*/
if (hflag)
syslog(LOG_INFO, "login from %s on %s as %s",
hostname, tty, pwd->pw_name);
else
syslog(LOG_INFO, "login on %s as %s",
tty, pwd->pw_name);
#endif
/*
* If fflag is on, assume caller/authenticator has logged root
* login.
*/
if (rootlogin && fflag == 0) {
if (hflag)
syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
username, tty, hostname);
else
syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s",
username, tty);
}
/*
* Destroy environment unless user has requested its
* preservation - but preserve TERM in all cases
*/
term = getenv("TERM");
if (!pflag)
environ = envinit;
if (term != NULL) {
if (setenv("TERM", term, 0) == -1)
err(1, "setenv: cannot set TERM=%s", term);
}
/*
* PAM modules might add supplementary groups during pam_setcred().
*/
if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
syslog(LOG_ERR, "setusercontext() failed - exiting");
bail(NO_SLEEP_EXIT, 1);
}
pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_setcred()");
bail(NO_SLEEP_EXIT, 1);
}
pam_cred_established = 1;
pam_err = pam_open_session(pamh, pam_silent);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_open_session()");
bail(NO_SLEEP_EXIT, 1);
}
pam_session_established = 1;
/*
* We must fork() before setuid() because we need to call
* pam_close_session() as root.
*/
pid = fork();
if (pid < 0) {
err(1, "fork");
} else if (pid != 0) {
/*
* Parent: wait for child to finish, then clean up
* session.
*/
int status;
setproctitle("-%s [pam]", getprogname());
waitpid(pid, &status, 0);
bail(NO_SLEEP_EXIT, 0);
}
/*
* NOTICE: We are now in the child process!
*/
/*
* Add any environment variables the PAM modules may have set.
*/
export_pam_environment();
/*
* We're done with PAM now; our parent will deal with the rest.
*/
pam_end(pamh, 0);
pamh = NULL;
/*
* We don't need to be root anymore, so set the login name and
* the UID.
*/
if (setlogin(username) != 0) {
syslog(LOG_ERR, "setlogin(%s): %m - exiting", username);
bail(NO_SLEEP_EXIT, 1);
}
if (setusercontext(lc, pwd, pwd->pw_uid,
LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) {
syslog(LOG_ERR, "setusercontext() failed - exiting");
exit(1);
}
if (setenv("SHELL", pwd->pw_shell, 1) == -1)
err(1, "setenv: cannot set SHELL=%s", pwd->pw_shell);
if (setenv("HOME", pwd->pw_dir, 1) == -1)
err(1, "setenv: cannot set HOME=%s", pwd->pw_dir);
/* Overwrite "term" from login.conf(5) for any known TERM */
if (term == NULL && (tp = stypeof(tty)) != NULL) {
if (setenv("TERM", tp, 1) == -1)
err(1, "setenv: cannot set TERM=%s", tp);
} else {
if (setenv("TERM", TERM_UNKNOWN, 0) == -1)
err(1, "setenv: cannot set TERM=%s", TERM_UNKNOWN);
}
if (setenv("LOGNAME", username, 1) == -1)
err(1, "setenv: cannot set LOGNAME=%s", username);
if (setenv("USER", username, 1) == -1)
err(1, "setenv: cannot set USER=%s", username);
if (setenv("PATH",
rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0) == -1) {
err(1, "setenv: cannot set PATH=%s",
rootlogin ? _PATH_STDPATH : _PATH_DEFPATH);
}
if (!quietlog) {
const char *cw;
cw = login_getcapstr(lc, "copyright", NULL, NULL);
if (cw == NULL || motd(cw) == -1)
printf("%s", copyright);
printf("\n");
cw = login_getcapstr(lc, "welcome", NULL, NULL);
if (cw != NULL && access(cw, F_OK) == 0)
motd(cw);
else
motd(_PATH_MOTDFILE);
if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 &&
login_getcapbool(lc, "nocheckmail", 0) == 0) {
char *cx;
/* $MAIL may have been set by class. */
cx = getenv("MAIL");
if (cx == NULL) {
asprintf(&cx, "%s/%s",
_PATH_MAILDIR, pwd->pw_name);
}
if (cx && stat(cx, &st) == 0 && st.st_size != 0)
printf("You have %smail.\n",
(st.st_mtime > st.st_atime) ? "new " : "");
if (getenv("MAIL") == NULL)
free(cx);
}
}
login_close(lc_user);
login_close(lc);
signal(SIGALRM, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGINT, SIG_DFL);
signal(SIGTSTP, SIG_IGN);
/*
* Login shells have a leading '-' in front of argv[0]
*/
p = strrchr(pwd->pw_shell, '/');
if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) {
syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size",
username);
errx(1, "shell exceeds maximum pathname size");
} else if (arg0 == NULL) {
err(1, "asprintf()");
}
execlp(shell, arg0, NULL);
err(1, "%s", shell);
/*
* That's it, folks!
*/
}
int
setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags)
{
quad_t p;
mode_t mymask;
login_cap_t *llc = NULL;
struct sigaction sa, prevsa;
struct rtprio rtp;
int error;
if (lc == NULL) {
if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL)
llc = lc; /* free this when we're done */
}
if (flags & LOGIN_SETPATH)
pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH;
/* we need a passwd entry to set these */
if (pwd == NULL)
flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN | LOGIN_SETMAC);
/* Set the process priority */
if (flags & LOGIN_SETPRIORITY) {
p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
if (p > PRIO_MAX) {
rtp.type = RTP_PRIO_IDLE;
rtp.prio = p - PRIO_MAX - 1;
p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p;
if (rtprio(RTP_SET, 0, &rtp))
syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
pwd ? pwd->pw_name : "-",
lc ? lc->lc_class : LOGIN_DEFCLASS);
} else if (p < PRIO_MIN) {
rtp.type = RTP_PRIO_REALTIME;
rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX);
p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p;
if (rtprio(RTP_SET, 0, &rtp))
syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
pwd ? pwd->pw_name : "-",
lc ? lc->lc_class : LOGIN_DEFCLASS);
} else {
if (setpriority(PRIO_PROCESS, 0, (int)p) != 0)
syslog(LOG_WARNING, "setpriority '%s' (%s): %m",
pwd ? pwd->pw_name : "-",
lc ? lc->lc_class : LOGIN_DEFCLASS);
}
}
/* Setup the user's group permissions */
if (flags & LOGIN_SETGROUP) {
if (setgid(pwd->pw_gid) != 0) {
syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid);
login_close(llc);
return (-1);
}
if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name,
(u_long)pwd->pw_gid);
login_close(llc);
return (-1);
}
}
/* Set up the user's MAC label. */
if ((flags & LOGIN_SETMAC) && mac_is_present(NULL) == 1) {
const char *label_string;
mac_t label;
label_string = login_getcapstr(lc, "label", NULL, NULL);
if (label_string != NULL) {
if (mac_from_text(&label, label_string) == -1) {
syslog(LOG_ERR, "mac_from_text('%s') for %s: %m",
pwd->pw_name, label_string);
return (-1);
}
if (mac_set_proc(label) == -1)
error = errno;
else
error = 0;
mac_free(label);
if (error != 0) {
syslog(LOG_ERR, "mac_set_proc('%s') for %s: %s",
label_string, pwd->pw_name, strerror(error));
return (-1);
}
}
}
/* Set the sessions login */
if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) {
syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name);
login_close(llc);
return (-1);
}
/* Inform the kernel about current login class */
if (lc != NULL && lc->lc_class != NULL && (flags & LOGIN_SETLOGINCLASS)) {
/*
* XXX: This is a workaround to fail gracefully in case the kernel
* does not support setloginclass(2).
*/
bzero(&sa, sizeof(sa));
sa.sa_handler = SIG_IGN;
sigfillset(&sa.sa_mask);
sigaction(SIGSYS, &sa, &prevsa);
error = setloginclass(lc->lc_class);
sigaction(SIGSYS, &prevsa, NULL);
if (error != 0) {
syslog(LOG_ERR, "setloginclass(%s): %m", lc->lc_class);
#ifdef notyet
login_close(llc);
return (-1);
#endif
}
}
mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0;
mymask = setlogincontext(lc, pwd, mymask, flags);
login_close(llc);
/* This needs to be done after anything that needs root privs */
if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) {
syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid);
return (-1); /* Paranoia again */
}
/*
* Now, we repeat some of the above for the user's private entries
*/
if (getuid() == uid && (lc = login_getuserclass(pwd)) != NULL) {
mymask = setlogincontext(lc, pwd, mymask, flags);
login_close(lc);
}
/* Finally, set any umask we've found */
if (flags & LOGIN_SETUMASK)
umask(mymask);
return (0);
}
int
setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags)
{
quad_t p;
mode_t mymask;
login_cap_t *llc = NULL;
struct rtprio rtp;
if (lc == NULL) {
if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL)
llc = lc; /* free this when we're done */
}
if (flags & LOGIN_SETPATH)
pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH;
/* we need a passwd entry to set these */
if (pwd == NULL)
flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN);
/* Set the process priority */
if (flags & LOGIN_SETPRIORITY) {
p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
if (p > PRIO_MAX) {
rtp.type = RTP_PRIO_IDLE;
rtp.prio = p - PRIO_MAX - 1;
p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p;
if (rtprio(RTP_SET, 0, &rtp))
syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
pwd ? pwd->pw_name : "-",
lc ? lc->lc_class : LOGIN_DEFCLASS);
} else if (p < PRIO_MIN) {
rtp.type = RTP_PRIO_REALTIME;
rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX);
p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p;
if (rtprio(RTP_SET, 0, &rtp))
syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
pwd ? pwd->pw_name : "-",
lc ? lc->lc_class : LOGIN_DEFCLASS);
} else {
if (setpriority(PRIO_PROCESS, 0, (int)p) != 0)
syslog(LOG_WARNING, "setpriority '%s' (%s): %m",
pwd ? pwd->pw_name : "-",
lc ? lc->lc_class : LOGIN_DEFCLASS);
}
}
/* Setup the user's group permissions */
if (flags & LOGIN_SETGROUP) {
if (setgid(pwd->pw_gid) != 0) {
syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid);
login_close(llc);
return (-1);
}
if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name,
(u_long)pwd->pw_gid);
login_close(llc);
return (-1);
}
}
/* Set the sessions login */
if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) {
syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name);
login_close(llc);
return (-1);
}
mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0;
mymask = setlogincontext(lc, pwd, mymask, flags);
login_close(llc);
/* This needs to be done after anything that needs root privs */
if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) {
syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid);
return (-1); /* Paranoia again */
}
/*
* Now, we repeat some of the above for the user's private entries
*/
if (getuid() == uid && (lc = login_getuserclass(pwd)) != NULL) {
mymask = setlogincontext(lc, pwd, mymask, flags);
login_close(lc);
}
/* Finally, set any umask we've found */
if (flags & LOGIN_SETUMASK)
umask(mymask);
return (0);
}
