144 lines
3.9 KiB
C
144 lines
3.9 KiB
C
/*-
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* Copyright (c) 2011 Dag-Erling Smørgrav
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <security/pam_appl.h>
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#include "openpam_impl.h"
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/*
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* OpenPAM internal
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*
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* Verify that the file or directory referenced by the given descriptor is
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* owned by either root or the arbitrator and that it is not writable by
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* group or other.
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*/
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int
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openpam_check_desc_owner_perms(const char *name, int fd)
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{
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uid_t root, arbitrator;
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struct stat sb;
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int serrno;
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root = 0;
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arbitrator = geteuid();
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if (fstat(fd, &sb) != 0) {
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serrno = errno;
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openpam_log(PAM_LOG_ERROR, "%s: %m", name);
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errno = serrno;
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return (-1);
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}
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if (!S_ISREG(sb.st_mode)) {
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openpam_log(PAM_LOG_ERROR,
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"%s: not a regular file", name);
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errno = EINVAL;
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return (-1);
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}
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if ((sb.st_uid != root && sb.st_uid != arbitrator) ||
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(sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
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openpam_log(PAM_LOG_ERROR,
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"%s: insecure ownership or permissions", name);
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errno = EPERM;
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return (-1);
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}
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return (0);
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}
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/*
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* OpenPAM internal
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*
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* Verify that a file or directory and all components of the path leading
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* up to it are owned by either root or the arbitrator and that they are
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* not writable by group or other.
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*
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* Note that openpam_check_desc_owner_perms() should be used instead if
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* possible to avoid a race between the ownership / permission check and
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* the actual open().
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*/
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int
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openpam_check_path_owner_perms(const char *path)
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{
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uid_t root, arbitrator;
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char pathbuf[PATH_MAX];
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struct stat sb;
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int len, serrno, tip;
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tip = 1;
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root = 0;
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arbitrator = geteuid();
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if (realpath(path, pathbuf) == NULL)
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return (-1);
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len = strlen(pathbuf);
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while (len > 0) {
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if (stat(pathbuf, &sb) != 0) {
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if (errno != ENOENT) {
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serrno = errno;
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openpam_log(PAM_LOG_ERROR, "%s: %m", pathbuf);
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errno = serrno;
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}
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return (-1);
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}
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if (tip && !S_ISREG(sb.st_mode)) {
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openpam_log(PAM_LOG_ERROR,
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"%s: not a regular file", pathbuf);
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errno = EINVAL;
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return (-1);
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}
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if ((sb.st_uid != root && sb.st_uid != arbitrator) ||
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(sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
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openpam_log(PAM_LOG_ERROR,
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"%s: insecure ownership or permissions", pathbuf);
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errno = EPERM;
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return (-1);
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}
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while (--len > 0 && pathbuf[len] != '/')
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pathbuf[len] = '\0';
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tip = 0;
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}
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return (0);
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}
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/*
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* NOPARSE
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*/
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