CasperSecurity
// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* mdp - make dummy policy
*
* When pointed at a kernel tree, builds a dummy policy for that kernel
* with exactly one type with full rights to itself.
*
* Copyright (C) IBM Corporation, 2006
*
* Authors: Serge E. Hallyn <serue@us.ibm.com>
*/
/* NOTE: we really do want to use the kernel headers here */
#define __EXPORTED_HEADERS__
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <linux/kconfig.h>
static void usage(char *name)
{
printf("usage: %s [-m] policy_file context_file\n", name);
exit(1);
}
/* Class/perm mapping support */
struct security_class_mapping {
const char *name;
const char *perms[sizeof(unsigned) * 8 + 1];
};
#include "classmap.h"
#include "initial_sid_to_string.h"
#include "policycap_names.h"
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
int main(int argc, char *argv[])
{
int i, j, mls = 0;
int initial_sid_to_string_len;
char **arg, *polout, *ctxout;
FILE *fout;
if (argc < 3)
usage(argv[0]);
arg = argv+1;
if (argc==4 && strcmp(argv[1], "-m") == 0) {
mls = 1;
arg++;
}
polout = *arg++;
ctxout = *arg;
fout = fopen(polout, "w");
if (!fout) {
printf("Could not open %s for writing\n", polout);
usage(argv[0]);
}
/* print out the classes */
for (i = 0; secclass_map[i].name; i++)
fprintf(fout, "class %s\n", secclass_map[i].name);
fprintf(fout, "\n");
initial_sid_to_string_len = sizeof(initial_sid_to_string) / sizeof (char *);
/* print out the sids */
for (i = 1; i < initial_sid_to_string_len; i++) {
const char *name = initial_sid_to_string[i];
if (name)
fprintf(fout, "sid %s\n", name);
else
fprintf(fout, "sid unused%d\n", i);
}
fprintf(fout, "\n");
/* print out the class permissions */
for (i = 0; secclass_map[i].name; i++) {
struct security_class_mapping *map = &secclass_map[i];
fprintf(fout, "class %s\n", map->name);
fprintf(fout, "{\n");
for (j = 0; map->perms[j]; j++)
fprintf(fout, "\t%s\n", map->perms[j]);
fprintf(fout, "}\n\n");
}
fprintf(fout, "\n");
/* print out mls declarations and constraints */
if (mls) {
fprintf(fout, "sensitivity s0;\n");
fprintf(fout, "sensitivity s1;\n");
fprintf(fout, "dominance { s0 s1 }\n");
fprintf(fout, "category c0;\n");
fprintf(fout, "category c1;\n");
fprintf(fout, "level s0:c0.c1;\n");
fprintf(fout, "level s1:c0.c1;\n");
#define SYSTEMLOW "s0"
#define SYSTEMHIGH "s1:c0.c1"
for (i = 0; secclass_map[i].name; i++) {
struct security_class_mapping *map = &secclass_map[i];
fprintf(fout, "mlsconstrain %s {\n", map->name);
for (j = 0; map->perms[j]; j++)
fprintf(fout, "\t%s\n", map->perms[j]);
/*
* This requires all subjects and objects to be
* single-level (l2 eq h2), and that the subject
* level dominate the object level (h1 dom h2)
* in order to have any permissions to it.
*/
fprintf(fout, "} (l2 eq h2 and h1 dom h2);\n\n");
}
}
/* enable all policy capabilities */
for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
fprintf(fout, "policycap %s;\n", selinux_policycap_names[i]);
/* types, roles, and allows */
fprintf(fout, "type base_t;\n");
fprintf(fout, "role base_r;\n");
fprintf(fout, "role base_r types { base_t };\n");
for (i = 0; secclass_map[i].name; i++)
fprintf(fout, "allow base_t base_t:%s *;\n",
secclass_map[i].name);
fprintf(fout, "user user_u roles { base_r }");
if (mls)
fprintf(fout, " level %s range %s - %s", SYSTEMLOW,
SYSTEMLOW, SYSTEMHIGH);
fprintf(fout, ";\n");
#define SUBJUSERROLETYPE "user_u:base_r:base_t"
#define OBJUSERROLETYPE "user_u:object_r:base_t"
/* default sids */
for (i = 1; i < initial_sid_to_string_len; i++) {
const char *name = initial_sid_to_string[i];
if (name)
fprintf(fout, "sid %s ", name);
else
fprintf(fout, "sid unused%d\n", i);
fprintf(fout, SUBJUSERROLETYPE "%s\n",
mls ? ":" SYSTEMLOW : "");
}
fprintf(fout, "\n");
#define FS_USE(behavior, fstype) \
fprintf(fout, "fs_use_%s %s " OBJUSERROLETYPE "%s;\n", \
behavior, fstype, mls ? ":" SYSTEMLOW : "")
/*
* Filesystems whose inode labels can be fetched via getxattr.
*/
#ifdef CONFIG_EXT2_FS_SECURITY
FS_USE("xattr", "ext2");
#endif
#ifdef CONFIG_EXT4_FS_SECURITY
#ifdef CONFIG_EXT4_USE_FOR_EXT2
FS_USE("xattr", "ext2");
#endif
FS_USE("xattr", "ext3");
FS_USE("xattr", "ext4");
#endif
#ifdef CONFIG_JFS_SECURITY
FS_USE("xattr", "jfs");
#endif
#ifdef CONFIG_REISERFS_FS_SECURITY
FS_USE("xattr", "reiserfs");
#endif
#ifdef CONFIG_JFFS2_FS_SECURITY
FS_USE("xattr", "jffs2");
#endif
#ifdef CONFIG_XFS_FS
FS_USE("xattr", "xfs");
#endif
#ifdef CONFIG_GFS2_FS
FS_USE("xattr", "gfs2");
#endif
#ifdef CONFIG_BTRFS_FS
FS_USE("xattr", "btrfs");
#endif
#ifdef CONFIG_F2FS_FS_SECURITY
FS_USE("xattr", "f2fs");
#endif
#ifdef CONFIG_OCFS2_FS
FS_USE("xattr", "ocsfs2");
#endif
#ifdef CONFIG_OVERLAY_FS
FS_USE("xattr", "overlay");
#endif
#ifdef CONFIG_SQUASHFS_XATTR
FS_USE("xattr", "squashfs");
#endif
/*
* Filesystems whose inodes are labeled from allocating task.
*/
FS_USE("task", "pipefs");
FS_USE("task", "sockfs");
/*
* Filesystems whose inode labels are computed from both
* the allocating task and the superblock label.
*/
#ifdef CONFIG_UNIX98_PTYS
FS_USE("trans", "devpts");
#endif
#ifdef CONFIG_HUGETLBFS
FS_USE("trans", "hugetlbfs");
#endif
#ifdef CONFIG_TMPFS
FS_USE("trans", "tmpfs");
#endif
#ifdef CONFIG_DEVTMPFS
FS_USE("trans", "devtmpfs");
#endif
#ifdef CONFIG_POSIX_MQUEUE
FS_USE("trans", "mqueue");
#endif
#define GENFSCON(fstype, prefix) \
fprintf(fout, "genfscon %s %s " OBJUSERROLETYPE "%s\n", \
fstype, prefix, mls ? ":" SYSTEMLOW : "")
/*
* Filesystems whose inodes are labeled from path prefix match
* relative to the filesystem root. Depending on the filesystem,
* only a single label for all inodes may be supported. Here
* we list the filesystem types for which per-file labeling is
* supported using genfscon; any other filesystem type can also
* be added by only with a single entry for all of its inodes.
*/
#ifdef CONFIG_PROC_FS
GENFSCON("proc", "/");
#endif
#ifdef CONFIG_SECURITY_SELINUX
GENFSCON("selinuxfs", "/");
#endif
#ifdef CONFIG_SYSFS
GENFSCON("sysfs", "/");
#endif
#ifdef CONFIG_DEBUG_FS
GENFSCON("debugfs", "/");
#endif
#ifdef CONFIG_TRACING
GENFSCON("tracefs", "/");
#endif
#ifdef CONFIG_PSTORE
GENFSCON("pstore", "/");
#endif
GENFSCON("cgroup", "/");
GENFSCON("cgroup2", "/");
fclose(fout);
fout = fopen(ctxout, "w");
if (!fout) {
printf("Wrote policy, but cannot open %s for writing\n", ctxout);
usage(argv[0]);
}
fprintf(fout, "/ " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
fprintf(fout, "/.* " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
fclose(fout);
return 0;
}