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
  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                 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                         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 }