IABSD.fr/src/lib/libutil/check_expire.c

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• Author : deraadt
  Date : 2019-06-28 13:32:41
  Hash : df69c215
  Message : When system calls indicate an error they return -1, not some arbitrary value < 0. errno is only updated in this case. Change all (most?) callers of syscalls to follow this better, and let's see if this strictness helps us in the future.

• lib/libutil/check_expire.c

• /*	$OpenBSD: check_expire.c,v 1.13 2019/06/28 13:32:43 deraadt Exp $	*/
  
  /*
   * Copyright (c) 1997 Berkeley Software Design, Inc. 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 Berkeley Software Design,
   *	Inc.
   * 4. The name of Berkeley Software Design, Inc.  may not be used to endorse
   *    or promote products derived from this software without specific prior
   *    written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN, INC. ``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 BERKELEY SOFTWARE DESIGN, INC. 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.
   *
   *	BSDI $From: check_expire.c,v 2.1 1997/08/08 18:38:25 prb Exp $
   */
  
  #include <sys/types.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <pwd.h>
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  #include <login_cap.h>
  #include <bsd_auth.h>
  
  #include "util.h"
  
  static char *pwd_update(const struct passwd *, const struct passwd *);
  
  #define SECSPERDAY	(24 * 60 * 60)
  #define TWOWEEKS	(2 * 7 * SECSPERDAY)
  
  int
  login_check_expire(FILE *back, struct passwd *pwd, char *class, int lastchance)
  {
  	auth_session_t *as;
  	login_cap_t *lc;
  	quad_t dead, expire, warn;
  	char *p;
  
  	if ((as = auth_open()) == NULL) {
  		fprintf(back, BI_VALUE
  		    " errormsg Unable to create auth session\n");
  		fprintf(back, BI_REJECT "\n");
  		return (1);
  	}
  	if (auth_setpwd(as, pwd) < 0) {
  		fprintf(back, BI_VALUE
  		    " errormsg Unable to set pwd entry in auth session\n");
  		fprintf(back, BI_REJECT "\n");
  		return (1);
  	}
  
  	expire = auth_check_change(as);
  	auth_close(as);
  
  	if (expire != 0) {
  		fprintf(back, BI_VALUE " expire %qd\n", expire);
  
  		if (class == NULL)
  			class = pwd->pw_class;
  
  		if ((lc = login_getclass(class)) == NULL) {
  			dead = 0;
  			warn = 0;
  		} else {
  			dead = login_getcaptime(lc, "password-dead", 0, 0);
  			warn = login_getcaptime(lc, "password-warn",
  			    TWOWEEKS, TWOWEEKS);
  			if (dead < 0)
  				dead = 0;
  			if (warn < 0)
  				warn = 0;
  		}
  		login_close(lc);
  
  		/*
  		 * If their password is dead (expired longer than
  		 * password-dead) then just reject them.  If it is
  		 * expired but not dead yet, reject them with a
  		 * PWEXPIRED so login knows they can still sort of
  		 * get in.
  		 */
  		if (expire < -dead) {
  			fprintf(back, BI_VALUE
  			    " errormsg Your password has expired\n");
  			fprintf(back, BI_REJECT "\n");
  			return (1);
  		}
  		if (expire < 0) {
  			if (lastchance) {
  				struct passwd *npwd;
  
  				endpwent();
  
  				/*
  				 * Only let them play this game once.
  				 * Set their password change time to 1.
  				 * This will most certainly cause any
  				 * expired password to be dead, as well.
  				 */
  				npwd = pw_dup(pwd);
  				npwd->pw_change = 1;
  				p = pwd_update(npwd, pwd);
  				explicit_bzero(npwd->pw_passwd,
  				    strlen(npwd->pw_passwd));
  				free(npwd);
  				if (p != NULL) {
  					char *errval = auth_mkvalue(p);
  					if (errval != NULL) {
  						fprintf(back, BI_VALUE
  						    " errormsg %s", errval);
  						free(errval);
  					}
  					fprintf(back, BI_REJECT "\n");
  					return (1);
  				}
  			}
  			fprintf(back, BI_VALUE
  			    " errormsg Your password has expired\n");
  			fprintf(back, BI_PWEXPIRED "\n");
  			return (1);
  		}
  
  		/*
  		 * If their password is not expired but is about to expire
  		 * then warn them.
  		 */
  		if (expire <= warn) {
  			fprintf(back, BI_VALUE
  			    " warnmsg Your password expires on %s\n",
  			    ctime(&pwd->pw_change));
  		}
  	}
  	return (0);
  }
  
  static char *
  pwd_update(const struct passwd *pwd, const struct passwd *opwd)
  {
  	int tfd, pfd;
  
  	pw_init();
  	tfd = pw_lock(0);
  	if (tfd == -1) {
  		if (errno == EEXIST)
  			return("the passwd file is busy.");
  		else
  			return("can't open passwd temp file");
  	}
  
  	pfd = open(_PATH_MASTERPASSWD, O_RDONLY|O_CLOEXEC, 0);
  	if (pfd == -1) {
  		pw_abort();
  		return(strerror(errno));
  	}
  
  	pw_copy(pfd, tfd, pwd, opwd);
  	if (pw_mkdb(pwd->pw_name, 0) == -1) {
  		pw_abort();
  		return("unable to update password database");
  	}
  
  	return(NULL);
  }