IABSD.fr/src/libexec/mail.local/locking.c

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• Author : millert
  Date : 2020-05-27 03:12:06
  Hash : da07b1a3
  Message : Remove support for world-writable mail spools. They won't work any more due to pledge restrictions so just print an error and exit if the spool is world-writable. OK beck@

• libexec/mail.local/locking.c

• /*	$OpenBSD: locking.c,v 1.15 2020/05/27 03:12:06 millert Exp $	*/
  
  /*
   * Copyright (c) 1996-1998 Theo de Raadt <deraadt@theos.com>
   * Copyright (c) 1996-1998 David Mazieres <dm@lcs.mit.edu>
   * 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. The name of the authors may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED ``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 AUTHORS 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 <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <pwd.h>
  #include <syslog.h>
  #include <unistd.h>
  #include <limits.h>
  #include <errno.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdarg.h>
  #include "pathnames.h"
  #include "mail.local.h"
  
  static char lpath[PATH_MAX];
  
  void
  rellock(void)
  {
  
  	if (lpath[0])
  		unlink(lpath);
  }
  
  int
  getlock(const char *name, struct passwd *pw)
  {
  	struct stat sb;
  	int lfd=-1;
  	int tries = 0;
  
  	(void)snprintf(lpath, sizeof lpath, "%s/%s.lock",
  	    _PATH_MAILDIR, name);
  
  	if (stat(_PATH_MAILDIR, &sb) != -1 &&
  	    (sb.st_mode & S_IWOTH) == S_IWOTH) {
  		mwarn("%s: will not deliver to world-writable spool",
  		    _PATH_MAILDIR);
  	} else {
  		/*
  		 * Only root can write the spool directory.
  		 */
  		while (1) {
  			if ((lfd = open(lpath, O_CREAT|O_WRONLY|O_EXCL,
  			    S_IRUSR|S_IWUSR)) != -1)
  				break;
  			if (tries > 9) {
  				mwarn("%s: %s", lpath, strerror(errno));
  				return(-1);
  			}
  			sleep(1U << tries);
  			tries++;
  		}
  	}
  	return(lfd);
  }
  
  void
  mwarn(const char *fmt, ...)
  {
  	va_list ap;
  
  	va_start(ap, fmt);
  	vsyslog(LOG_ERR, fmt, ap);
  	va_end(ap);
  }
  
  void
  merr(int eval, const char *fmt, ...)
  {
  	va_list ap;
  
  	va_start(ap, fmt);
  	vsyslog(LOG_ERR, fmt, ap);
  	va_end(ap);
  	exit(eval);
  }