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