/scripts/selinux/mdp/mdp.c

  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
 39int main(int argc, char *argv[])
 40{
 41	int i, j, mls = 0;
 42	int initial_sid_to_string_len;
 43	char **arg, *polout, *ctxout;
 44
 45	FILE *fout;
 46
 47	if (argc < 3)
 48		usage(argv[0]);
 49	arg = argv+1;
 50	if (argc==4 && strcmp(argv[1], "-m") == 0) {
 51		mls = 1;
 52		arg++;
 53	}
 54	polout = *arg++;
 55	ctxout = *arg;
 56
 57	fout = fopen(polout, "w");
 58	if (!fout) {
 59		printf("Could not open %s for writing\n", polout);
 60		usage(argv[0]);
 61	}
 62
 63	/* print out the classes */
 64	for (i = 0; secclass_map[i].name; i++)
 65		fprintf(fout, "class %s\n", secclass_map[i].name);
 66	fprintf(fout, "\n");
 67
 68	initial_sid_to_string_len = sizeof(initial_sid_to_string) / sizeof (char *);
 69	/* print out the sids */
 70	for (i = 1; i < initial_sid_to_string_len; i++)
 71		fprintf(fout, "sid %s\n", initial_sid_to_string[i]);
 72	fprintf(fout, "\n");
 73
 74	/* print out the class permissions */
 75	for (i = 0; secclass_map[i].name; i++) {
 76		struct security_class_mapping *map = &secclass_map[i];
 77		fprintf(fout, "class %s\n", map->name);
 78		fprintf(fout, "{\n");
 79		for (j = 0; map->perms[j]; j++)
 80			fprintf(fout, "\t%s\n", map->perms[j]);
 81		fprintf(fout, "}\n\n");
 82	}
 83	fprintf(fout, "\n");
 84
 85	/* print out mls declarations and constraints */
 86	if (mls) {
 87		fprintf(fout, "sensitivity s0;\n");
 88		fprintf(fout, "sensitivity s1;\n");
 89		fprintf(fout, "dominance { s0 s1 }\n");
 90		fprintf(fout, "category c0;\n");
 91		fprintf(fout, "category c1;\n");
 92		fprintf(fout, "level s0:c0.c1;\n");
 93		fprintf(fout, "level s1:c0.c1;\n");
 94#define SYSTEMLOW "s0"
 95#define SYSTEMHIGH "s1:c0.c1"
 96		for (i = 0; secclass_map[i].name; i++) {
 97			struct security_class_mapping *map = &secclass_map[i];
 98
 99			fprintf(fout, "mlsconstrain %s {\n", map->name);
100			for (j = 0; map->perms[j]; j++)
101				fprintf(fout, "\t%s\n", map->perms[j]);
102			/*
103			 * This requires all subjects and objects to be
104			 * single-level (l2 eq h2), and that the subject
105			 * level dominate the object level (h1 dom h2)
106			 * in order to have any permissions to it.
107			 */
108			fprintf(fout, "} (l2 eq h2 and h1 dom h2);\n\n");
109		}
110	}
111
112	/* types, roles, and allows */
113	fprintf(fout, "type base_t;\n");
114	fprintf(fout, "role base_r;\n");
115	fprintf(fout, "role base_r types { base_t };\n");
116	for (i = 0; secclass_map[i].name; i++)
117		fprintf(fout, "allow base_t base_t:%s *;\n",
118			secclass_map[i].name);
119	fprintf(fout, "user user_u roles { base_r }");
120	if (mls)
121		fprintf(fout, " level %s range %s - %s", SYSTEMLOW,
122			SYSTEMLOW, SYSTEMHIGH);
123	fprintf(fout, ";\n");
124
125#define SUBJUSERROLETYPE "user_u:base_r:base_t"
126#define OBJUSERROLETYPE "user_u:object_r:base_t"
127
128	/* default sids */
129	for (i = 1; i < initial_sid_to_string_len; i++)
130		fprintf(fout, "sid %s " SUBJUSERROLETYPE "%s\n",
131			initial_sid_to_string[i], mls ? ":" SYSTEMLOW : "");
132	fprintf(fout, "\n");
133
134#define FS_USE(behavior, fstype)			    \
135	fprintf(fout, "fs_use_%s %s " OBJUSERROLETYPE "%s;\n", \
136		behavior, fstype, mls ? ":" SYSTEMLOW : "")
137
138	/*
139	 * Filesystems whose inode labels can be fetched via getxattr.
140	 */
141#ifdef CONFIG_EXT2_FS_SECURITY
142	FS_USE("xattr", "ext2");
143#endif
144#ifdef CONFIG_EXT4_FS_SECURITY
145#ifdef CONFIG_EXT4_USE_FOR_EXT2
146	FS_USE("xattr", "ext2");
147#endif
148	FS_USE("xattr", "ext3");
149	FS_USE("xattr", "ext4");
150#endif
151#ifdef CONFIG_JFS_SECURITY
152	FS_USE("xattr", "jfs");
153#endif
154#ifdef CONFIG_REISERFS_FS_SECURITY
155	FS_USE("xattr", "reiserfs");
156#endif
157#ifdef CONFIG_JFFS2_FS_SECURITY
158	FS_USE("xattr", "jffs2");
159#endif
160#ifdef CONFIG_XFS_FS
161	FS_USE("xattr", "xfs");
162#endif
163#ifdef CONFIG_GFS2_FS
164	FS_USE("xattr", "gfs2");
165#endif
166#ifdef CONFIG_BTRFS_FS
167	FS_USE("xattr", "btrfs");
168#endif
169#ifdef CONFIG_F2FS_FS_SECURITY
170	FS_USE("xattr", "f2fs");
171#endif
172#ifdef CONFIG_OCFS2_FS
173	FS_USE("xattr", "ocsfs2");
174#endif
175#ifdef CONFIG_OVERLAY_FS
176	FS_USE("xattr", "overlay");
177#endif
178#ifdef CONFIG_SQUASHFS_XATTR
179	FS_USE("xattr", "squashfs");
180#endif
181
182	/*
183	 * Filesystems whose inodes are labeled from allocating task.
184	 */
185	FS_USE("task", "pipefs");
186	FS_USE("task", "sockfs");
187
188	/*
189	 * Filesystems whose inode labels are computed from both
190	 * the allocating task and the superblock label.
191	 */
192#ifdef CONFIG_UNIX98_PTYS
193	FS_USE("trans", "devpts");
194#endif
195#ifdef CONFIG_HUGETLBFS
196	FS_USE("trans", "hugetlbfs");
197#endif
198#ifdef CONFIG_TMPFS
199	FS_USE("trans", "tmpfs");
200#endif
201#ifdef CONFIG_DEVTMPFS
202	FS_USE("trans", "devtmpfs");
203#endif
204#ifdef CONFIG_POSIX_MQUEUE
205	FS_USE("trans", "mqueue");
206#endif
207
208#define GENFSCON(fstype, prefix)			     \
209	fprintf(fout, "genfscon %s %s " OBJUSERROLETYPE "%s\n", \
210		fstype, prefix, mls ? ":" SYSTEMLOW : "")
211
212	/*
213	 * Filesystems whose inodes are labeled from path prefix match
214	 * relative to the filesystem root.  Depending on the filesystem,
215	 * only a single label for all inodes may be supported.  Here
216	 * we list the filesystem types for which per-file labeling is
217	 * supported using genfscon; any other filesystem type can also
218	 * be added by only with a single entry for all of its inodes.
219	 */
220#ifdef CONFIG_PROC_FS
221	GENFSCON("proc", "/");
222#endif
223#ifdef CONFIG_SECURITY_SELINUX
224	GENFSCON("selinuxfs", "/");
225#endif
226#ifdef CONFIG_SYSFS
227	GENFSCON("sysfs", "/");
228#endif
229#ifdef CONFIG_DEBUG_FS
230	GENFSCON("debugfs", "/");
231#endif
232#ifdef CONFIG_TRACING
233	GENFSCON("tracefs", "/");
234#endif
235#ifdef CONFIG_PSTORE
236	GENFSCON("pstore", "/");
237#endif
238	GENFSCON("cgroup", "/");
239	GENFSCON("cgroup2", "/");
240
241	fclose(fout);
242
243	fout = fopen(ctxout, "w");
244	if (!fout) {
245		printf("Wrote policy, but cannot open %s for writing\n", ctxout);
246		usage(argv[0]);
247	}
248	fprintf(fout, "/ " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
249	fprintf(fout, "/.* " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
250	fclose(fout);
251
252	return 0;
253}