freebsd-dev/usr.bin/login/login.c
Alex Richardson 4d552825ec usr.bin/login: send errors to console if syslog isn't running
I was debugging why login(1) wasn't working as expected on a minimal
MFS_ROOT disk image. This image doesn't have syslogd running so the
warnings were lost and I had to use GDB to find out why login(1) was
failing (missing PAM libraries) instead of being able to see it in
the console output.

MFC after:	1 week
Reviewed By:	pfg
Differential Revision: https://reviews.freebsd.org/D30892
2021-07-06 10:51:16 +01:00

1039 lines
25 KiB
C

/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2002 Networks Associates Technologies, Inc.
* All rights reserved.
*
* Portions of this software were developed for the FreeBSD Project by
* ThinkSec AS and NAI Labs, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
* ("CBOSS"), as part of the DARPA CHATS research program.
*
* 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.
*/
#if 0
#ifndef lint
static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94";
#endif
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* login [ name ]
* login -h hostname (for telnetd, etc.)
* login -f name (for pre-authenticated login: datakit, xterm, etc.)
*/
#include <sys/param.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <login_cap.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 <unistd.h>
#include <security/pam_appl.h>
#include <security/openpam.h>
#include "login.h"
#include "pathnames.h"
static int auth_pam(void);
static void bail(int, int);
static void bail_internal(int, int, int);
static int export(const char *);
static void export_pam_environment(void);
static int motd(const char *);
static void badlogin(char *);
static char *getloginname(void);
static void pam_syslog(const char *);
static void pam_cleanup(void);
static void refused(const char *, const char *, int);
static const char *stypeof(char *);
static void sigint(int);
static void timedout(int);
static void bail_sig(int);
static void usage(void);
#define TTYGRPNAME "tty" /* group to own ttys */
#define DEFAULT_BACKOFF 3
#define DEFAULT_RETRIES 10
#define DEFAULT_PROMPT "login: "
#define DEFAULT_PASSWD_PROMPT "Password:"
#define TERM_UNKNOWN "su"
#define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */
#define NO_SLEEP_EXIT 0
#define SLEEP_EXIT 5
/*
* This bounds the time given to login. Not a define so it can
* be patched on machines where it's too small.
*/
static u_int timeout = 300;
/* Buffer for signal handling of timeout */
static jmp_buf timeout_buf;
struct passwd *pwd;
static int failures;
static char *envinit[1]; /* empty environment list */
/*
* Command line flags and arguments
*/
static int fflag; /* -f: do not perform authentication */
static int hflag; /* -h: login from remote host */
static char *hostname; /* hostname from command line */
static int pflag; /* -p: preserve environment */
/*
* User name
*/
static char *username; /* user name */
static char *olduser; /* previous user name */
/*
* Prompts
*/
static char default_prompt[] = DEFAULT_PROMPT;
static const char *prompt;
static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT;
static const char *passwd_prompt;
static char *tty;
/*
* PAM data
*/
static pam_handle_t *pamh = NULL;
static struct pam_conv pamc = { openpam_ttyconv, NULL };
static int pam_err;
static int pam_silent = PAM_SILENT;
static int pam_cred_established;
static int pam_session_established;
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;
sigset_t mask, omask;
struct sigaction sa;
#ifdef USE_BSM_AUDIT
char auditsuccess = 1;
#endif
sa.sa_flags = SA_RESTART;
(void)sigfillset(&sa.sa_mask);
sa.sa_handler = SIG_IGN;
(void)sigaction(SIGQUIT, &sa, NULL);
(void)sigaction(SIGINT, &sa, NULL);
(void)sigaction(SIGHUP, &sa, NULL);
if (setjmp(timeout_buf)) {
if (failures)
badlogin(username);
(void)fprintf(stderr, "Login timed out after %d seconds\n",
timeout);
bail(NO_SLEEP_EXIT, 0);
}
sa.sa_handler = timedout;
(void)sigaction(SIGALRM, &sa, NULL);
(void)alarm(timeout);
(void)setpriority(PRIO_PROCESS, 0, 0);
openlog("login", LOG_CONS, 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());
closefrom(3);
/*
* Get current TTY
*/
ttyn = ttyname(STDIN_FILENO);
if (ttyn == NULL || *ttyn == '\0') {
(void)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;
(void)setpriority(PRIO_PROCESS, 0, -4);
rval = auth_pam();
(void)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
(void)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 */
(void)alarm((u_int)0);
(void)sigemptyset(&mask);
(void)sigaddset(&mask, SIGHUP);
(void)sigaddset(&mask, SIGTERM);
(void)sigprocmask(SIG_BLOCK, &mask, &omask);
sa.sa_handler = bail_sig;
(void)sigaction(SIGHUP, &sa, NULL);
(void)sigaction(SIGTERM, &sa, NULL);
endpwent();
#ifdef USE_BSM_AUDIT
/* Audit successful login. */
if (auditsuccess)
au_login_success();
#endif
/*
* This needs to happen before login_getpwclass to support
* home directories on GSS-API authenticated NFS where the
* kerberos credentials need to be saved so that the kernel
* can authenticate to the NFS server.
*/
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;
/*
* 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.
*/
(void)setegid(pwd->pw_gid);
(void)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);
}
}
(void)seteuid(euid);
(void)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);
#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)
setenv("TERM", term, 0);
/*
* 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_REINITIALIZE_CRED);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_setcred()");
bail(NO_SLEEP_EXIT, 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.
*
* If we get SIGHUP or SIGTERM, clean up the session
* and exit right away. This will make the terminal
* inaccessible and send SIGHUP to the foreground
* process group.
*/
int status;
setproctitle("-%s [pam]", getprogname());
(void)sigprocmask(SIG_SETMASK, &omask, NULL);
waitpid(pid, &status, 0);
(void)sigprocmask(SIG_BLOCK, &mask, NULL);
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);
}
(void)setenv("SHELL", pwd->pw_shell, 1);
(void)setenv("HOME", pwd->pw_dir, 1);
/* Overwrite "term" from login.conf(5) for any known TERM */
if (term == NULL && (tp = stypeof(tty)) != NULL)
(void)setenv("TERM", tp, 1);
else
(void)setenv("TERM", TERM_UNKNOWN, 0);
(void)setenv("LOGNAME", username, 1);
(void)setenv("USER", username, 1);
(void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0);
if (!quietlog) {
const char *cw;
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)
(void)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);
sa.sa_handler = SIG_DFL;
(void)sigaction(SIGALRM, &sa, NULL);
(void)sigaction(SIGQUIT, &sa, NULL);
(void)sigaction(SIGINT, &sa, NULL);
(void)sigaction(SIGTERM, &sa, NULL);
(void)sigaction(SIGHUP, &sa, NULL);
sa.sa_handler = SIG_IGN;
(void)sigaction(SIGTSTP, &sa, NULL);
(void)sigprocmask(SIG_SETMASK, &omask, NULL);
/*
* 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, (char *)0);
err(1, "%s", shell);
/*
* That's it, folks!
*/
}
/*
* Attempt to authenticate the user using PAM. Returns 0 if the user is
* authenticated, or 1 if not authenticated. If some sort of PAM system
* error occurs (e.g., the "/etc/pam.conf" file is missing) then this
* function returns -1. This can be used as an indication that we should
* fall back to a different authentication mechanism.
*/
static int
auth_pam(void)
{
const char *tmpl_user;
const void *item;
int rval;
pam_err = pam_authenticate(pamh, pam_silent);
switch (pam_err) {
case PAM_SUCCESS:
/*
* With PAM we support the concept of a "template"
* user. The user enters a login name which is
* authenticated by PAM, usually via a remote service
* such as RADIUS or TACACS+. If authentication
* succeeds, a different but related "template" name
* is used for setting the credentials, shell, and
* home directory. The name the user enters need only
* exist on the remote authentication server, but the
* template name must be present in the local password
* database.
*
* This is supported by two various mechanisms in the
* individual modules. However, from the application's
* point of view, the template user is always passed
* back as a changed value of the PAM_USER item.
*/
pam_err = pam_get_item(pamh, PAM_USER, &item);
if (pam_err == PAM_SUCCESS) {
tmpl_user = (const char *)item;
if (strcmp(username, tmpl_user) != 0)
pwd = getpwnam(tmpl_user);
} else {
pam_syslog("pam_get_item(PAM_USER)");
}
rval = 0;
break;
case PAM_AUTH_ERR:
case PAM_USER_UNKNOWN:
case PAM_MAXTRIES:
rval = 1;
break;
default:
pam_syslog("pam_authenticate()");
rval = -1;
break;
}
if (rval == 0) {
pam_err = pam_acct_mgmt(pamh, pam_silent);
switch (pam_err) {
case PAM_SUCCESS:
break;
case PAM_NEW_AUTHTOK_REQD:
pam_err = pam_chauthtok(pamh,
pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK);
if (pam_err != PAM_SUCCESS) {
pam_syslog("pam_chauthtok()");
rval = 1;
}
break;
default:
pam_syslog("pam_acct_mgmt()");
rval = 1;
break;
}
}
if (rval != 0) {
pam_end(pamh, pam_err);
pamh = NULL;
}
return (rval);
}
/*
* Export any environment variables PAM modules may have set
*/
static void
export_pam_environment(void)
{
char **pam_env;
char **pp;
pam_env = pam_getenvlist(pamh);
if (pam_env != NULL) {
for (pp = pam_env; *pp != NULL; pp++) {
(void)export(*pp);
free(*pp);
}
}
}
/*
* Perform sanity checks on an environment variable:
* - Make sure there is an '=' in the string.
* - Make sure the string doesn't run on too long.
* - Do not export certain variables. This list was taken from the
* Solaris pam_putenv(3) man page.
* Then export it.
*/
static int
export(const char *s)
{
static const char *noexport[] = {
"SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH",
"IFS", "PATH", NULL
};
char *p;
const char **pp;
size_t n;
int rv;
if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL)
return (0);
if (strncmp(s, "LD_", 3) == 0)
return (0);
for (pp = noexport; *pp != NULL; pp++) {
n = strlen(*pp);
if (s[n] == '=' && strncmp(s, *pp, n) == 0)
return (0);
}
*p = '\0';
rv = setenv(s, p + 1, 1);
*p = '=';
if (rv == -1)
return (0);
return (1);
}
static void
usage(void)
{
(void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n");
exit(1);
}
/*
* Prompt user and read login name from stdin.
*/
static char *
getloginname(void)
{
char *nbuf, *p;
int ch;
nbuf = malloc(MAXLOGNAME);
if (nbuf == NULL)
err(1, "malloc()");
do {
(void)printf("%s", prompt);
for (p = nbuf; (ch = getchar()) != '\n'; ) {
if (ch == EOF) {
badlogin(username);
bail(NO_SLEEP_EXIT, 0);
}
if (p < nbuf + MAXLOGNAME - 1)
*p++ = ch;
}
} while (p == nbuf);
*p = '\0';
if (nbuf[0] == '-') {
pam_silent = 0;
memmove(nbuf, nbuf + 1, strlen(nbuf));
} else {
pam_silent = PAM_SILENT;
}
return nbuf;
}
/*
* SIGINT handler for motd().
*/
static volatile int motdinterrupt;
static void
sigint(int signo __unused)
{
motdinterrupt = 1;
}
/*
* Display the contents of a file (such as /etc/motd).
*/
static int
motd(const char *motdfile)
{
struct sigaction newint, oldint;
FILE *f;
int ch;
if ((f = fopen(motdfile, "r")) == NULL)
return (-1);
motdinterrupt = 0;
newint.sa_handler = sigint;
newint.sa_flags = 0;
sigfillset(&newint.sa_mask);
sigaction(SIGINT, &newint, &oldint);
while ((ch = fgetc(f)) != EOF && !motdinterrupt)
putchar(ch);
sigaction(SIGINT, &oldint, NULL);
if (ch != EOF || ferror(f)) {
fclose(f);
return (-1);
}
fclose(f);
return (0);
}
/*
* SIGALRM handler, to enforce login prompt timeout.
*
* XXX This can potentially confuse the hell out of PAM. We should
* XXX instead implement a conversation function that returns
* XXX PAM_CONV_ERR when interrupted by a signal, and have the signal
* XXX handler just set a flag.
*/
static void
timedout(int signo __unused)
{
longjmp(timeout_buf, signo);
}
static void
badlogin(char *name)
{
if (failures == 0)
return;
if (hflag) {
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);
}
failures = 0;
}
const char *
stypeof(char *ttyid)
{
struct ttyent *t;
if (ttyid != NULL && *ttyid != '\0') {
t = getttynam(ttyid);
if (t != NULL && t->ty_type != NULL)
return (t->ty_type);
}
return (NULL);
}
static void
refused(const char *msg, const char *rtype, int lout)
{
if (msg != NULL)
printf("%s.\n", msg);
if (hflag)
syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s",
pwd->pw_name, rtype, hostname, tty);
else
syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s",
pwd->pw_name, rtype, tty);
if (lout)
bail(SLEEP_EXIT, 1);
}
/*
* Log a PAM error
*/
static void
pam_syslog(const char *msg)
{
syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err));
}
/*
* Shut down PAM
*/
static void
pam_cleanup(void)
{
if (pamh != NULL) {
if (pam_session_established) {
pam_err = pam_close_session(pamh, 0);
if (pam_err != PAM_SUCCESS)
pam_syslog("pam_close_session()");
}
pam_session_established = 0;
if (pam_cred_established) {
pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED);
if (pam_err != PAM_SUCCESS)
pam_syslog("pam_setcred()");
}
pam_cred_established = 0;
pam_end(pamh, pam_err);
pamh = NULL;
}
}
static void
bail_internal(int sec, int eval, int signo)
{
struct sigaction sa;
pam_cleanup();
#ifdef USE_BSM_AUDIT
if (pwd != NULL)
audit_logout();
#endif
(void)sleep(sec);
if (signo == 0)
exit(eval);
else {
sa.sa_handler = SIG_DFL;
sa.sa_flags = 0;
(void)sigemptyset(&sa.sa_mask);
(void)sigaction(signo, &sa, NULL);
(void)sigaddset(&sa.sa_mask, signo);
(void)sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL);
raise(signo);
exit(128 + signo);
}
}
/*
* Exit, optionally after sleeping a few seconds
*/
static void
bail(int sec, int eval)
{
bail_internal(sec, eval, 0);
}
/*
* Exit because of a signal.
* This is not async-signal safe, so only call async-signal safe functions
* while the signal is unmasked.
*/
static void
bail_sig(int signo)
{
bail_internal(NO_SLEEP_EXIT, 0, signo);
}