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Implement secpolicy_vnode_setid_retain()
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Don't unconditionally return 0 (i.e. retain SUID/SGID).
Test CAP_FSETID capability.

https://github.com/pjd/pjdfstest/blob/master/tests/chmod/12.t
which expects SUID/SGID to be dropped on write(2) by non-owner fails
without this. Most filesystems make this decision within VFS by using
a generic file write for fops.

Signed-off-by: Tomohiro Kusumi <[email protected]>
kusumi committed Jul 17, 2019
1 parent 8062b76 commit 38e0c9e
Showing 9 changed files with 211 additions and 1 deletion.
1 change: 1 addition & 0 deletions configure.ac
Original file line number Diff line number Diff line change
@@ -330,6 +330,7 @@ AC_CONFIG_FILES([
tests/zfs-tests/tests/functional/snapshot/Makefile
tests/zfs-tests/tests/functional/snapused/Makefile
tests/zfs-tests/tests/functional/sparse/Makefile
tests/zfs-tests/tests/functional/suid/Makefile
tests/zfs-tests/tests/functional/alloc_class/Makefile
tests/zfs-tests/tests/functional/threadsappend/Makefile
tests/zfs-tests/tests/functional/tmpfile/Makefile
2 changes: 1 addition & 1 deletion module/zfs/policy.c
Original file line number Diff line number Diff line change
@@ -209,7 +209,7 @@ secpolicy_vnode_setdac(const cred_t *cr, uid_t owner)
int
secpolicy_vnode_setid_retain(const cred_t *cr, boolean_t issuidroot)
{
return (0);
return (priv_policy_user(cr, CAP_FSETID, B_FALSE, EPERM));
}

/*
4 changes: 4 additions & 0 deletions tests/runfiles/linux.run
Original file line number Diff line number Diff line change
@@ -850,6 +850,10 @@ tags = ['functional', 'snapused']
tests = ['sparse_001_pos']
tags = ['functional', 'sparse']

[tests/functional/suid]
tests = ['suid_write_to_file']
tags = ['functional', 'suid']

[tests/functional/threadsappend]
tests = ['threadsappend_001_pos']
tags = ['functional', 'threadsappend']
1 change: 1 addition & 0 deletions tests/zfs-tests/tests/functional/Makefile.am
Original file line number Diff line number Diff line change
@@ -68,6 +68,7 @@ SUBDIRS = \
snapshot \
snapused \
sparse \
suid \
threadsappend \
tmpfile \
trim \
1 change: 1 addition & 0 deletions tests/zfs-tests/tests/functional/suid/.gitignore
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@@ -0,0 +1 @@
/suid_write_to_file
12 changes: 12 additions & 0 deletions tests/zfs-tests/tests/functional/suid/Makefile.am
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@@ -0,0 +1,12 @@
include $(top_srcdir)/config/Rules.am

pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/suid

dist_pkgdata_SCRIPTS = \
cleanup.ksh \
setup.ksh

pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/suid

pkgexec_PROGRAMS = suid_write_to_file
suid_write_to_file_SOURCES = suid_write_to_file.c
34 changes: 34 additions & 0 deletions tests/zfs-tests/tests/functional/suid/cleanup.ksh
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@@ -0,0 +1,34 @@
#!/bin/ksh -p
#
# CDDL HEADER START
#
# The contents of this file are subject to the terms of the
# Common Development and Distribution License (the "License").
# You may not use this file except in compliance with the License.
#
# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
# or http://www.opensolaris.org/os/licensing.
# See the License for the specific language governing permissions
# and limitations under the License.
#
# When distributing Covered Code, include this CDDL HEADER in each
# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
# If applicable, add the following below this CDDL HEADER, with the
# fields enclosed by brackets "[]" replaced with your own identifying
# information: Portions Copyright [yyyy] [name of copyright owner]
#
# CDDL HEADER END
#

#
# Copyright 2007 Sun Microsystems, Inc. All rights reserved.
# Use is subject to license terms.
#

#
# Copyright (c) 2019 by Tomohiro Kusumi. All rights reserved.
#

. $STF_SUITE/include/libtest.shlib

#default_cleanup
35 changes: 35 additions & 0 deletions tests/zfs-tests/tests/functional/suid/setup.ksh
Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
#!/bin/ksh -p
#
# CDDL HEADER START
#
# The contents of this file are subject to the terms of the
# Common Development and Distribution License (the "License").
# You may not use this file except in compliance with the License.
#
# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
# or http://www.opensolaris.org/os/licensing.
# See the License for the specific language governing permissions
# and limitations under the License.
#
# When distributing Covered Code, include this CDDL HEADER in each
# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
# If applicable, add the following below this CDDL HEADER, with the
# fields enclosed by brackets "[]" replaced with your own identifying
# information: Portions Copyright [yyyy] [name of copyright owner]
#
# CDDL HEADER END
#

#
# Copyright 2007 Sun Microsystems, Inc. All rights reserved.
# Use is subject to license terms.
#

#
# Copyright (c) 2019 by Tomohiro Kusumi. All rights reserved.
#

. $STF_SUITE/include/libtest.shlib

#DISK=${DISKS%% *}
#default_setup $DISK
122 changes: 122 additions & 0 deletions tests/zfs-tests/tests/functional/suid/suid_write_to_file.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,122 @@
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2019 by Tomohiro Kusumi. All rights reserved.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

/*
* DESCRIPTION:
* Verify SUID/SGID bit on write(2) by non-owner.
* Also see https://github.com/pjd/pjdfstest/blob/master/tests/chmod/12.t
*
* STRATEGY:
* 1. creat(2) a file with SUID/SGID.
* 2. write(2) to the file with uid=65534.
* 3. stat(2) the file and verify .st_mode value.
*/

static void
test_stat_mode(mode_t mode)
{
struct stat st;
int i, fd;
char fpath[1024];
char *penv[] = {"TESTDIR", "TESTFILE0"};
char buf[] = "test";
mode_t res;

/*
* Get the environment variable values.
*/
for (i = 0; i < sizeof (penv) / sizeof (char *); i++) {
if ((penv[i] = getenv(penv[i])) == NULL) {
fprintf(stderr, "getenv(penv[%d])\n", i);
exit(1);
}
}

umask(0);
if (stat(penv[0], &st) == -1 && mkdir(penv[0], mode) == -1) {
perror("mkdir");
exit(2);
}

snprintf(fpath, sizeof (fpath), "%s/%s", penv[0], penv[1]);
unlink(fpath);
if (stat(fpath, &st) == 0) {
fprintf(stderr, "%s exists\n", fpath);
exit(3);
}

fd = creat(fpath, mode);
if (fd == -1) {
perror("creat");
exit(4);
}
close(fd);

if (setuid(65534) == -1) {
perror("setuid");
exit(5);
}

fd = open(fpath, O_RDWR);
if (fd == -1) {
perror("open");
exit(6);
}

if (write(fd, buf, sizeof (buf)) == -1) {
perror("write");
exit(7);
}
close(fd);

if (stat(fpath, &st) == -1) {
perror("stat");
exit(8);
}
unlink(fpath);

/* Verify SUID/SGID are dropped */
res = st.st_mode & (0777 | S_ISUID | S_ISGID);
if (res != (mode & 0777)) {
fprintf(stderr, "stat(2) %o\n", res);
exit(9);
}
}

int
main(int argc, char *argv[])
{
fprintf(stdout, "Verify SUID/SGID bit on write(2) by non-owner\n");
test_stat_mode(0777 | S_ISUID | S_ISGID);

return (0);
}

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