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Introduce support for Mandatory Access Control and extensible

Browse source 
kernel access control.

Provide a library to manage user file system firewall-like rules
supported by the mac_bsdextended.ko security model.  The kernel
module exports the current rule set using sysctl, and this
library provides a front end that includes support for retrieving
and setting rules, as well as printing and parsing them.

Note: as with other userland components, this is a WIP.  However,
when used in combination with the soon-to-be-committed ugidfw,
it can actually be quite useful in multi-user environments to
allow the administrator to limit inter-user file operations without
resorting to heavier weight labeled security policies.

Obtained form:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
This commit is contained in:
Robert Watson 2002-08-02 07:07:35 +00:00
parent ba0fbe9637
commit 46d1a925c2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=101206
3 changed files with 785 additions and 0 deletions
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11
lib/libugidfw/Makefile Normal file
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# $FreeBSD$
LIB= ugidfw
SHLIB_MAJOR= 1
SHLIB_MINOR= 0
CFLAGS+= -Wall
SRCS= ugidfw.c
INCS= ugidfw.h
NOMAN= yes
.include <bsd.lib.mk>

712
lib/libugidfw/ugidfw.c Normal file
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/*-
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by NAI Labs, the
* Security Research Division of Network Associates, Inc. under
* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
* CHATS research program.
*
* 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 names 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 BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <security/mac_bsdextended/mac_bsdextended.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ugidfw.h>
/*
* Text format for rules: rules contain subjectand object elements, mode.
* Each element takes the form "[not] [uid number] [gid number]".
* The total form is "subject [element] object [element] mode [mode]".
* At least * one of a uid or gid entry must be present; both may also be
* present.
*/
#define MIB "security.mac.bsdextended"
int
bsde_rule_to_string(struct mac_bsdextended_rule *rule, char *buf, size_t buflen)
{
struct group *grp;
struct passwd *pwd;
char *cur;
size_t left, len;
int anymode, unknownmode, truncated;
cur = buf;
left = buflen;
truncated = 0;
if (rule->mbr_subject.mbi_flags & (MBI_UID_DEFINED |
MBI_GID_DEFINED)) {
len = snprintf(cur, left, "subject ");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
if (rule->mbr_subject.mbi_flags & MBI_NEGATED) {
len = snprintf(cur, left, "not ");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (rule->mbr_subject.mbi_flags & MBI_UID_DEFINED) {
pwd = getpwuid(rule->mbr_subject.mbi_uid);
if (pwd != NULL) {
len = snprintf(cur, left, "uid %s ",
pwd->pw_name);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
} else {
len = snprintf(cur, left, "uid %u ",
rule->mbr_subject.mbi_uid);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
}
if (rule->mbr_subject.mbi_flags & MBI_GID_DEFINED) {
grp = getgrgid(rule->mbr_subject.mbi_gid);
if (grp != NULL) {
len = snprintf(cur, left, "gid %s ",
grp->gr_name);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
} else {
len = snprintf(cur, left, "gid %u ",
rule->mbr_subject.mbi_gid);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
}
}
if (rule->mbr_object.mbi_flags & (MBI_UID_DEFINED |
MBI_GID_DEFINED)) {
len = snprintf(cur, left, "object ");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
if (rule->mbr_object.mbi_flags & MBI_NEGATED) {
len = snprintf(cur, left, "not ");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (rule->mbr_object.mbi_flags & MBI_UID_DEFINED) {
pwd = getpwuid(rule->mbr_object.mbi_uid);
if (pwd != NULL) {
len = snprintf(cur, left, "uid %s ",
pwd->pw_name);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
} else {
len = snprintf(cur, left, "uid %u ",
rule->mbr_object.mbi_uid);
left -= len;
cur += len;
}
}
if (rule->mbr_object.mbi_flags & MBI_GID_DEFINED) {
grp = getgrgid(rule->mbr_object.mbi_gid);
if (grp != NULL) {
len = snprintf(cur, left, "gid %s ",
grp->gr_name);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
} else {
len = snprintf(cur, left, "gid %u ",
rule->mbr_object.mbi_gid);
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
}
}
len = snprintf(cur, left, "mode ");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
anymode = (rule->mbr_mode & VALLPERM);
unknownmode = (rule->mbr_mode & ~VALLPERM);
if (rule->mbr_mode & VADMIN) {
len = snprintf(cur, left, "a");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (rule->mbr_mode & VREAD) {
len = snprintf(cur, left, "r");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (rule->mbr_mode & VSTAT) {
len = snprintf(cur, left, "s");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (rule->mbr_mode & VWRITE) {
len = snprintf(cur, left, "w");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (rule->mbr_mode & VEXEC) {
len = snprintf(cur, left, "x");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (!anymode) {
len = snprintf(cur, left, "n");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
if (unknownmode) {
len = snprintf(cur, left, "?");
if (len < 0 || len > left)
goto truncated;
left -= len;
cur += len;
}
return (0);
truncated:
return (-1);
}
int
bsde_parse_identity(int argc, char *argv[],
struct mac_bsdextended_identity *identity, size_t buflen, char *errstr)
{
struct group *grp;
struct passwd *pwd;
int uid_seen, gid_seen, not_seen;
int current;
char *endp;
long value;
uid_t uid;
gid_t gid;
size_t len;
if (argc == 0) {
len = snprintf(errstr, buflen, "Identity must not be empty");
return (-1);
}
current = 0;
/* First element might be "not". */
if (strcmp("not", argv[0]) == 0) {
not_seen = 1;
current++;
} else
not_seen = 0;
if (current >= argc) {
len = snprintf(errstr, buflen, "Identity short");
return (-1);
}
uid_seen = 0;
uid = 0;
gid_seen = 0;
gid = 0;
/* First phrase: uid [uid] or gid[gid]. */
if (strcmp("uid", argv[current]) == 0) {
if (current + 2 > argc) {
len = snprintf(errstr, buflen, "uid short");
return (-1);
}
pwd = getpwnam(argv[current+1]);
if (pwd != NULL)
uid = pwd->pw_uid;
else {
value = strtol(argv[current+1], &endp, 10);
if (*endp != '\0') {
len = snprintf(errstr, buflen,
"invalid uid: '%s'",
argv[current+1]);
return (-1);
}
uid = value;
}
uid_seen = 1;
current += 2;
} else if (strcmp("gid", argv[current]) == 0) {
if (current + 2 > argc) {
len = snprintf(errstr, buflen, "gid short");
return (-1);
}
grp = getgrnam(argv[current+1]);
if (grp != NULL)
gid = grp->gr_gid;
else {
value = strtol(argv[current+1], &endp, 10);
if (*endp != '\0') {
len = snprintf(errstr, buflen,
"invalid gid: '%s'",
argv[current+1]);
return (-1);
}
gid = value;
}
gid_seen = 1;
current += 2;
} else {
len = snprintf(errstr, buflen, "'%s' not expected",
argv[current]);
return (-1);
}
/* Onto optional second phrase. */
if (current + 1 < argc) {
/* Second phrase: uid [uid] or gid [gid], but not a repeat. */
if (strcmp("uid", argv[current]) == 0) {
if (uid_seen) {
len = snprintf(errstr, buflen,
"Only one uid permitted per identity clause");
return (-1);
}
if (current + 2 > argc) {
len = snprintf(errstr, buflen, "uid short");
return (-1);
}
value = strtol(argv[current+1], &endp, 10);
if (*endp != '\0') {
len = snprintf(errstr, buflen, "invalid uid: '%s'",
argv[current+1]);
return (-1);
}
uid = value;
uid_seen = 1;
current += 2;
} else if (strcmp("gid", argv[current]) == 0) {
if (gid_seen) {
len = snprintf(errstr, buflen,
"Only one gid permitted per identity clause");
return (-1);
}
if (current + 2 > argc) {
len = snprintf(errstr, buflen, "gid short");
return (-1);
}
value = strtol(argv[current+1], &endp, 10);
if (*endp != '\0') {
len = snprintf(errstr, buflen, "invalid gid: '%s'",
argv[current+1]);
return (-1);
}
gid = value;
gid_seen = 1;
current += 2;
} else {
len = snprintf(errstr, buflen, "'%s' not expected",
argv[current]);
return (-1);
}
}
if (current +1 < argc) {
len = snprintf(errstr, buflen, "'%s' not expected",
argv[current]);
return (-1);
}
/* Fill out the identity. */
identity->mbi_flags = 0;
if (not_seen)
identity->mbi_flags |= MBI_NEGATED;
if (uid_seen) {
identity->mbi_flags |= MBI_UID_DEFINED;
identity->mbi_uid = uid;
} else
identity->mbi_uid = 0;
if (gid_seen) {
identity->mbi_flags |= MBI_GID_DEFINED;
identity->mbi_gid = gid;
} else
identity->mbi_gid = 0;
return (0);
}
int
bsde_parse_mode(int argc, char *argv[], mode_t *mode, size_t buflen,
char *errstr)
{
size_t len;
int i;
if (argc == 0) {
len = snprintf(errstr, buflen, "mode expects mode value");
return (-1);
}
if (argc != 1) {
len = snprintf(errstr, buflen, "'%s' unexpected", argv[1]);
return (-1);
}
*mode = 0;
for (i = 0; i < strlen(argv[0]); i++) {
switch (argv[0][i]) {
case 'a':
*mode |= VADMIN;
break;
case 'r':
*mode |= VREAD;
break;
case 's':
*mode |= VSTAT;
break;
case 'w':
*mode |= VWRITE;
break;
case 'x':
*mode |= VEXEC;
break;
case 'n':
/* ignore */
break;
default:
len = snprintf(errstr, buflen, "Unknown mode letter: %c",
argv[0][i]);
return (-1);
}
}
return (0);
}
int
bsde_parse_rule(int argc, char *argv[], struct mac_bsdextended_rule *rule,
size_t buflen, char *errstr)
{
int subject, subject_elements, subject_elements_length;
int object, object_elements, object_elements_length;
int mode, mode_elements, mode_elements_length;
int error, i;
size_t len;
bzero(rule, sizeof(*rule));
if (argc < 1) {
len = snprintf(errstr, buflen, "Rule must begin with subject");
return (-1);
}
if (strcmp(argv[0], "subject") != 0) {
len = snprintf(errstr, buflen, "Rule must begin with subject");
return (-1);
}
subject = 0;
subject_elements = 1;
/* Search forward for object. */
object = -1;
for (i = 1; i < argc; i++)
if (strcmp(argv[i], "object") == 0)
object = i;
if (object == -1) {
len = snprintf(errstr, buflen, "Rule must contain an object");
return (-1);
}
/* Search forward for mode. */
mode = -1;
for (i = object; i < argc; i++)
if (strcmp(argv[i], "mode") == 0)
mode = i;
if (mode == -1) {
len = snprintf(errstr, buflen, "Rule must contain mode");
return (-1);
}
subject_elements_length = object - subject - 1;
object_elements = object + 1;
object_elements_length = mode - object_elements;
mode_elements = mode + 1;
mode_elements_length = argc - mode_elements;
error = bsde_parse_identity(subject_elements_length,
argv + subject_elements, &rule->mbr_subject, buflen, errstr);
if (error)
return (-1);
error = bsde_parse_identity(object_elements_length,
argv + object_elements, &rule->mbr_object, buflen, errstr);
if (error)
return (-1);
error = bsde_parse_mode(mode_elements_length, argv + mode_elements,
&rule->mbr_mode, buflen, errstr);
if (error)
return (-1);
return (0);
}
int
bsde_parse_rule_string(const char *string, struct mac_bsdextended_rule *rule,
size_t buflen, char *errstr)
{
char *stringdup, *stringp, *argv[20], **ap;
int argc, error;
stringp = stringdup = strdup(string);
while (*stringp == ' ' || *stringp == '\t')
stringp++;
argc = 0;
for (ap = argv; (*ap = strsep(&stringp, " \t")) != NULL;) {
argc++;
if (**ap != '\0')
if (++ap >= &argv[20])
break;
}
error = bsde_parse_rule(argc, argv, rule, buflen, errstr);
free(stringdup);
return (error);
}
int
bsde_get_mib(const char *string, int *name, int *namelen)
{
int error, len;
len = *namelen;
error = sysctlnametomib(string, name, &len);
if (error)
return (error);
*namelen = len;
return (0);
}
int
bsde_get_rule_count(size_t buflen, char *errstr)
{
size_t len;
int error;
int rule_count;
len = sizeof(rule_count);
error = sysctlbyname(MIB ".rule_count", &rule_count, &len, NULL, NULL);
if (error) {
len = snprintf(errstr, buflen, strerror(errno));
return (-1);
}
if (len != sizeof(rule_count)) {
len = snprintf(errstr, buflen, "Data error in %s.rule_count",
MIB);
return (-1);
}
return (rule_count);
}
int
bsde_get_rule_slots(size_t buflen, char *errstr)
{
size_t len;
int error;
int rule_slots;
len = sizeof(rule_slots);
error = sysctlbyname(MIB ".rule_slots", &rule_slots, &len, NULL,
NULL);
if (error) {
len = snprintf(errstr, buflen, strerror(errno));
return (-1);
}
if (len != sizeof(rule_slots)) {
len = snprintf(errstr, buflen, "Data error in %s.rule_slots",
MIB);
return (-1);
}
return (rule_slots);
}
/*
* Returns 0 for success;
* Returns -1 for failure;
* Returns -2 for not present
*/
int
bsde_get_rule(int rulenum, struct mac_bsdextended_rule *rule, size_t errlen,
char *errstr)
{
int name[10];
size_t len, size;
int error;
len = 10;
error = bsde_get_mib(MIB ".rules", name, &len);
if (error) {
len = snprintf(errstr, errlen, "%s: %s", MIB ".rules",
strerror(errno));
return (-1);
}
size = sizeof(*rule);
name[len] = rulenum;
len++;
error = sysctl(name, len, rule, &size, NULL, 0);
if (error == -1 && errno == ENOENT)
return (-2);
if (error) {
len = snprintf(errstr, errlen, "%s.%d: %s", MIB ".rules",
rulenum, strerror(errno));
return (-1);
} else if (size != sizeof(*rule)) {
len = snprintf(errstr, errlen, "Data error in %s.%d: %s",
MIB ".rules", rulenum, strerror(errno));
return (-1);
}
return (0);
}
int
bsde_delete_rule(int rulenum, size_t buflen, char *errstr)
{
struct mac_bsdextended_rule rule;
int name[10];
size_t len, size;
int error;
len = 10;
error = bsde_get_mib(MIB ".rules", name, &len);
if (error) {
len = snprintf(errstr, buflen, "%s: %s", MIB ".rules",
strerror(errno));
return (-1);
}
name[len] = rulenum;
len++;
size = sizeof(rule);
error = sysctl(name, len, NULL, NULL, &rule, 0);
if (error) {
len = snprintf(errstr, buflen, "%s.%d: %s", MIB ".rules",
rulenum, strerror(errno));
return (-1);
}
return (0);
}
int
bsde_set_rule(int rulenum, struct mac_bsdextended_rule *rule, size_t buflen,
char *errstr)
{
int name[10];
size_t len, size;
int error;
len = 10;
error = bsde_get_mib(MIB ".rules", name, &len);
if (error) {
len = snprintf(errstr, buflen, "%s: %s", MIB ".rules",
strerror(errno));
return (-1);
}
name[len] = rulenum;
len++;
size = sizeof(*rule);
error = sysctl(name, len, NULL, NULL, rule, size);
if (error) {
len = snprintf(errstr, buflen, "%s.%d: %s", MIB ".rules",
rulenum, strerror(errno));
return (-1);
}
return (0);
}

62
lib/libugidfw/ugidfw.h Normal file
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/*-
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by NAI Labs, the
* Security Research Division of Network Associates, Inc. under
* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
* CHATS research program.
*
* 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 names 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 BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#ifndef _UGIDFW_H
#define _UGIDFW_H
__BEGIN_DECLS
int bsde_rule_to_string(struct mac_bsdextended_rule *rule, char *buf,
size_t buflen);
int bsde_parse_identity(int argc, char *argv[],
struct mac_bsdextended_identity *identity, size_t buflen,
char *errstr);
int bsde_parse_mode(int argc, char *argv[], mode_t *mode, size_t buflen,
char *errstr);
int bsde_parse_rule(int argc, char *argv[],
struct mac_bsdextended_rule *rule, size_t buflen, char *errstr);
int bsde_parse_rule_string(const char *string,
struct mac_bsdextended_rule *rule, size_t buflen, char *errstr);
int bsde_get_mib(const char *string, int *name, int *namelen);
int bsde_get_rule_count(size_t buflen, char *errstr);
int bsde_get_rule_slots(size_t buflen, char *errstr);
int bsde_get_rule(int rulenum, struct mac_bsdextended_rule *rule,
size_t errlen, char *errstr);
int bsde_delete_rule(int rulenum, size_t buflen, char *errstr);
int bsde_set_rule(int rulenum, struct mac_bsdextended_rule *rule,
size_t buflen, char *errstr);
__END_DECLS
#endif