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
24 static 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 */
31 struct 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
42 int 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
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