bd76450bdb
implemented properly for a number of kernel subsystems. In general, they try to exercise the privilege first as the root user, then as a test user, in order to determine when privilege is being checked. Currently, these tests do not compare inside/outside jail, and probably should be enhanced to do that. Sponsored by: nCircle Network Security, Inc. Obtained from: TrustedBSD Project
329 lines
8.1 KiB
C
329 lines
8.1 KiB
C
/*-
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* Copyright (c) 2006 nCircle Network Security, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert N. M. Watson for the TrustedBSD
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* Project under contract to nCircle Network Security, Inc.
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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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*
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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, NCIRCLE NETWORK SECURITY,
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* INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Check that privilege is required for a variety of administrative
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* activities on a file owned by another user. Admin privileges are required
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* for the following services:
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*
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* - Set file flags.
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* - Set utimes to non-NULL.
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* - Set file mode.
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* - Set file ownership.
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* - Remove a file from a sticky directory. (XXXRW: Not tested here.)
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* - Set the ACL on a file. (XXXRW: Not tested here.)
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* - Delete the ACL on a file. (XXXRW: Not tested here.)
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <err.h>
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#include <errno.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 "main.h"
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static u_long
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getflags(char *fpathp)
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{
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struct stat sb;
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if (stat(fpathp, &sb) < 0)
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err(-1, "stat(%s)", fpathp);
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return (sb.st_flags);
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}
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static void
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priv_vfs_admin_chflags(void)
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{
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char fpath[1024];
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u_long flags;
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int error;
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/*
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* Test that setting file flags works as and not as the file owner
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* when running with privilege, but only as the file owner when
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* running without privilege.
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*/
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setup_file(fpath, UID_ROOT, GID_WHEEL, 0600);
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flags = getflags(fpath);
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flags |= UF_NODUMP;
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if (chflags(fpath, flags) < 0) {
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warn("chflags(%s, UF_NODUMP) owner as root", fpath);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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flags = getflags(fpath);
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flags |= UF_NODUMP;
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if (chflags(fpath, flags) < 0) {
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warn("chflags(%s, UF_NODUMP) !owner as root", fpath);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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flags = getflags(fpath);
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flags |= UF_NODUMP;
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set_euid(UID_OWNER);
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if (chflags(fpath, flags) < 0) {
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warn("chflags(%s, UF_NODUMP) owner as !root", fpath);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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flags = getflags(fpath);
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flags |= UF_NODUMP;
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set_euid(UID_OTHER);
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error = chflags(fpath, flags);
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if (error == 0) {
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warnx("chflags(%s, UF_NODUMP) succeeded !owner as !root",
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fpath);
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goto out;
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}
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if (errno != EPERM) {
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warn("chflags(%s, UF_NODUMP) wrong errno %d !owner a !root",
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fpath, errno);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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out:
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(void)seteuid(UID_ROOT);
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(void)unlink(fpath);
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}
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static void
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priv_vfs_admin_utimes(void)
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{
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struct timeval tv[2];
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char fpath[1024];
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int error;
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/*
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* Actual values don't matter here.
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*/
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tv[0].tv_sec = 0;
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tv[0].tv_usec = 0;
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tv[1].tv_sec = 0;
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tv[1].tv_usec = 0;
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/*
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* When using a non-NULL argument to utimes(), must either hold
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* privilege or be the file owner. Check all four possible
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* combinations of privilege, ownership.
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*/
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setup_file(fpath, UID_ROOT, GID_WHEEL, 0600);
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if (utimes(fpath, tv) < 0) {
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warn("utimes(%s, !NULL) owner as root", fpath);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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if (utimes(fpath, tv) < 0) {
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warn("utimes(%s, !NULL) !owner as root", fpath);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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set_euid(UID_OWNER);
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if (utimes(fpath, tv) < 0) {
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warn("utimes(%s, !NULL) owner as !root", fpath);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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set_euid(UID_OTHER);
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error = utimes(fpath, tv);
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if (error == 0) {
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warnx("utimes(%s, !NULL) succeeded !owner as !root",
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fpath);
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goto out;
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}
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if (errno != EPERM) {
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warn("utimes(%s, !NULL) wrong errno %d !owner a !root",
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fpath, errno);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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out:
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(void)seteuid(UID_ROOT);
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(void)unlink(fpath);
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}
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static void
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priv_vfs_admin_chmod(void)
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{
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char fpath[1024];
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int error;
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/*
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* Test that setting file permissions works either as file owner or
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* not when running with privilege, but only as file owner when
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* running without privilege.
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*/
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setup_file(fpath, UID_ROOT, GID_WHEEL, 0600);
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if (chmod(fpath, 0640) < 0) {
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warn("chmod(%s, 0640) owner as root", fpath);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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if (chmod(fpath, 0640) < 0) {
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warn("chmod(%s, 0640) !owner as root", fpath);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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set_euid(UID_OWNER);
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if (chmod(fpath, 0640) < 0) {
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warn("chmod(%s, 0640) owner as !root", fpath);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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set_euid(UID_OTHER);
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error = chmod(fpath, 0640);
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if (error == 0) {
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warnx("chmod(%s, 0640) succeeded !owner as !root",
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fpath);
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goto out;
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}
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if (errno != EPERM) {
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warn("chmod(%s, 0640) wrong errno %d !owner a !root",
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fpath, errno);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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out:
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(void)seteuid(UID_ROOT);
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(void)unlink(fpath);
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}
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static const gid_t gidset[] = { GID_WHEEL, GID_OWNER, GID_OTHER};
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static void
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priv_vfs_admin_chown(void)
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{
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char fpath[1024];
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int error;
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/*
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* Test that the group of the file can only be changed with privilege
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* or as the owner. These test is run last as it frobs the group
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* context. We change the file group from one group we're in to
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* another we're in to avoid any other access control checks failing.
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*/
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if (setgroups(3, gidset) < 0)
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err(-1, "priv_vfs_admin_chown:setgroups(3, {%d, %d, %d})",
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GID_WHEEL, GID_OWNER, GID_OTHER);
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/*
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* Test that setting file permissions works either as file owner or
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* not when running with privilege, but only as file owner when
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* running without privilege.
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*/
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setup_file(fpath, UID_ROOT, GID_WHEEL, 0600);
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if (chown(fpath, -1, GID_OWNER) < 0) {
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warn("chown(%s, %d) owner as root", fpath, GID_OWNER);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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if (chown(fpath, -1, GID_OWNER) < 0) {
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warn("chown(%s, %d) !owner as root", fpath, GID_OWNER);
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goto out;
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}
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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set_euid(UID_OWNER);
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if (chown(fpath, -1, GID_OWNER) < 0) {
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warn("chown(%s, %d) owner as !root", fpath, GID_OWNER);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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setup_file(fpath, UID_OWNER, GID_OWNER, 0600);
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set_euid(UID_OTHER);
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error = chown(fpath, -1, GID_OWNER);
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if (error == 0) {
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warnx("chown(%s, %d) succeeded !owner as !root",
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fpath, GID_OWNER);
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goto out;
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}
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if (errno != EPERM) {
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warn("chown(%s, %d) wrong errno %d !owner a !root",
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fpath, GID_OWNER, errno);
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goto out;
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}
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set_euid(UID_ROOT);
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(void)unlink(fpath);
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out:
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(void)seteuid(UID_ROOT);
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(void)unlink(fpath);
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}
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void
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priv_vfs_admin(void)
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{
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assert_root();
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priv_vfs_admin_chflags();
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priv_vfs_admin_utimes();
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priv_vfs_admin_chmod();
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priv_vfs_admin_chown(); /* Run this last. */
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}
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