1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * mdp - make dummy policy
5 *
6 * When pointed at a kernel tree, builds a dummy policy for that kernel
7 * with exactly one type with full rights to itself.
8 *
9 * Copyright (C) IBM Corporation, 2006
10 *
11 * Authors: Serge E. Hallyn <serue@us.ibm.com>
12 */
13
14
15/* NOTE: we really do want to use the kernel headers here */
16#define __EXPORTED_HEADERS__
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <unistd.h>
21#include <string.h>
22#include <linux/kconfig.h>
23
24static void usage(char *name)
25{
26	printf("usage: %s [-m] policy_file context_file\n", name);
27	exit(1);
28}
29
30/* Class/perm mapping support */
31struct security_class_mapping {
32	const char *name;
33	const char *perms[sizeof(unsigned) * 8 + 1];
34};
35
36#include "classmap.h"
37#include "initial_sid_to_string.h"
38#include "policycap_names.h"
39
40#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
41
42int main(int argc, char *argv[])
43{
44	int i, j, mls = 0;
45	int initial_sid_to_string_len;
46	char **arg, *polout, *ctxout;
47
48	FILE *fout;
49
50	if (argc < 3)
51		usage(argv[0]);
52	arg = argv+1;
53	if (argc==4 && strcmp(argv[1], "-m") == 0) {
54		mls = 1;
55		arg++;
56	}
57	polout = *arg++;
58	ctxout = *arg;
59
60	fout = fopen(polout, "w");
61	if (!fout) {
62		printf("Could not open %s for writing\n", polout);
63		usage(argv[0]);
64	}
65
66	/* print out the classes */
67	for (i = 0; secclass_map[i].name; i++)
68		fprintf(fout, "class %s\n", secclass_map[i].name);
69	fprintf(fout, "\n");
70
71	initial_sid_to_string_len = sizeof(initial_sid_to_string) / sizeof (char *);
72	/* print out the sids */
73	for (i = 1; i < initial_sid_to_string_len; i++) {
74		const char *name = initial_sid_to_string[i];
75
76		if (name)
77			fprintf(fout, "sid %s\n", name);
78		else
79			fprintf(fout, "sid unused%d\n", i);
80	}
81	fprintf(fout, "\n");
82
83	/* print out the class permissions */
84	for (i = 0; secclass_map[i].name; i++) {
85		const struct security_class_mapping *map = &secclass_map[i];
86		fprintf(fout, "class %s\n", map->name);
87		fprintf(fout, "{\n");
88		for (j = 0; map->perms[j]; j++)
89			fprintf(fout, "\t%s\n", map->perms[j]);
90		fprintf(fout, "}\n\n");
91	}
92	fprintf(fout, "\n");
93
94	/* print out mls declarations and constraints */
95	if (mls) {
96		fprintf(fout, "sensitivity s0;\n");
97		fprintf(fout, "sensitivity s1;\n");
98		fprintf(fout, "dominance { s0 s1 }\n");
99		fprintf(fout, "category c0;\n");
100		fprintf(fout, "category c1;\n");
101		fprintf(fout, "level s0:c0.c1;\n");
102		fprintf(fout, "level s1:c0.c1;\n");
103#define SYSTEMLOW "s0"
104#define SYSTEMHIGH "s1:c0.c1"
105		for (i = 0; secclass_map[i].name; i++) {
106			const struct security_class_mapping *map = &secclass_map[i];
107
108			fprintf(fout, "mlsconstrain %s {\n", map->name);
109			for (j = 0; map->perms[j]; j++)
110				fprintf(fout, "\t%s\n", map->perms[j]);
111			/*
112			 * This requires all subjects and objects to be
113			 * single-level (l2 eq h2), and that the subject
114			 * level dominate the object level (h1 dom h2)
115			 * in order to have any permissions to it.
116			 */
117			fprintf(fout, "} (l2 eq h2 and h1 dom h2);\n\n");
118		}
119	}
120
121	/* enable all policy capabilities */
122	for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
123		fprintf(fout, "policycap %s;\n", selinux_policycap_names[i]);
124
125	/* types, roles, and allows */
126	fprintf(fout, "type base_t;\n");
127	fprintf(fout, "role base_r;\n");
128	fprintf(fout, "role base_r types { base_t };\n");
129	for (i = 0; secclass_map[i].name; i++)
130		fprintf(fout, "allow base_t base_t:%s *;\n",
131			secclass_map[i].name);
132	fprintf(fout, "user user_u roles { base_r }");
133	if (mls)
134		fprintf(fout, " level %s range %s - %s", SYSTEMLOW,
135			SYSTEMLOW, SYSTEMHIGH);
136	fprintf(fout, ";\n");
137
138#define SUBJUSERROLETYPE "user_u:base_r:base_t"
139#define OBJUSERROLETYPE "user_u:object_r:base_t"
140
141	/* default sids */
142	for (i = 1; i < initial_sid_to_string_len; i++) {
143		const char *name = initial_sid_to_string[i];
144
145		if (name)
146			fprintf(fout, "sid %s ", name);
147		else
148			fprintf(fout, "sid unused%d\n", i);
149		fprintf(fout, SUBJUSERROLETYPE "%s\n",
150			mls ? ":" SYSTEMLOW : "");
151	}
152	fprintf(fout, "\n");
153
154#define FS_USE(behavior, fstype)			    \
155	fprintf(fout, "fs_use_%s %s " OBJUSERROLETYPE "%s;\n", \
156		behavior, fstype, mls ? ":" SYSTEMLOW : "")
157
158	/*
159	 * Filesystems whose inode labels can be fetched via getxattr.
160	 */
161#ifdef CONFIG_EXT2_FS_SECURITY
162	FS_USE("xattr", "ext2");
163#endif
164#ifdef CONFIG_EXT4_FS_SECURITY
165#ifdef CONFIG_EXT4_USE_FOR_EXT2
166	FS_USE("xattr", "ext2");
167#endif
168	FS_USE("xattr", "ext3");
169	FS_USE("xattr", "ext4");
170#endif
171#ifdef CONFIG_JFS_SECURITY
172	FS_USE("xattr", "jfs");
173#endif
174#ifdef CONFIG_REISERFS_FS_SECURITY
175	FS_USE("xattr", "reiserfs");
176#endif
177#ifdef CONFIG_JFFS2_FS_SECURITY
178	FS_USE("xattr", "jffs2");
179#endif
180#ifdef CONFIG_XFS_FS
181	FS_USE("xattr", "xfs");
182#endif
183#ifdef CONFIG_GFS2_FS
184	FS_USE("xattr", "gfs2");
185#endif
186#ifdef CONFIG_BTRFS_FS
187	FS_USE("xattr", "btrfs");
188#endif
189#ifdef CONFIG_F2FS_FS_SECURITY
190	FS_USE("xattr", "f2fs");
191#endif
192#ifdef CONFIG_OCFS2_FS
193	FS_USE("xattr", "ocsfs2");
194#endif
195#ifdef CONFIG_OVERLAY_FS
196	FS_USE("xattr", "overlay");
197#endif
198#ifdef CONFIG_SQUASHFS_XATTR
199	FS_USE("xattr", "squashfs");
200#endif
201
202	/*
203	 * Filesystems whose inodes are labeled from allocating task.
204	 */
205	FS_USE("task", "pipefs");
206	FS_USE("task", "sockfs");
207
208	/*
209	 * Filesystems whose inode labels are computed from both
210	 * the allocating task and the superblock label.
211	 */
212#ifdef CONFIG_UNIX98_PTYS
213	FS_USE("trans", "devpts");
214#endif
215#ifdef CONFIG_HUGETLBFS
216	FS_USE("trans", "hugetlbfs");
217#endif
218#ifdef CONFIG_TMPFS
219	FS_USE("trans", "tmpfs");
220#endif
221#ifdef CONFIG_DEVTMPFS
222	FS_USE("trans", "devtmpfs");
223#endif
224#ifdef CONFIG_POSIX_MQUEUE
225	FS_USE("trans", "mqueue");
226#endif
227
228#define GENFSCON(fstype, prefix)			     \
229	fprintf(fout, "genfscon %s %s " OBJUSERROLETYPE "%s\n", \
230		fstype, prefix, mls ? ":" SYSTEMLOW : "")
231
232	/*
233	 * Filesystems whose inodes are labeled from path prefix match
234	 * relative to the filesystem root.  Depending on the filesystem,
235	 * only a single label for all inodes may be supported.  Here
236	 * we list the filesystem types for which per-file labeling is
237	 * supported using genfscon; any other filesystem type can also
238	 * be added by only with a single entry for all of its inodes.
239	 */
240#ifdef CONFIG_PROC_FS
241	GENFSCON("proc", "/");
242#endif
243#ifdef CONFIG_SECURITY_SELINUX
244	GENFSCON("selinuxfs", "/");
245#endif
246#ifdef CONFIG_SYSFS
247	GENFSCON("sysfs", "/");
248#endif
249#ifdef CONFIG_DEBUG_FS
250	GENFSCON("debugfs", "/");
251#endif
252#ifdef CONFIG_TRACING
253	GENFSCON("tracefs", "/");
254#endif
255#ifdef CONFIG_PSTORE
256	GENFSCON("pstore", "/");
257#endif
258	GENFSCON("cgroup", "/");
259	GENFSCON("cgroup2", "/");
260
261	fclose(fout);
262
263	fout = fopen(ctxout, "w");
264	if (!fout) {
265		printf("Wrote policy, but cannot open %s for writing\n", ctxout);
266		usage(argv[0]);
267	}
268	fprintf(fout, "/ " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
269	fprintf(fout, "/.* " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
270	fclose(fout);
271
272	return 0;
273}
274