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linux/scripts/selinux/mdp/mdp.c
Christian Göttsche ded34574d4 selinux: declare data arrays const 
The arrays for the policy capability names, the initial sid identifiers
and the class and permission names are not changed at runtime.  Declare
them const to avoid accidental modification.

Do not override the classmap and the initial sid list in the build time
script genheaders.

Check flose(3) is successful in genheaders.c, otherwise the written data
might be corrupted or incomplete.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: manual merge due to fuzz, minor style tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 15:53:49 -04:00

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// 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++) {
const 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++) {
const 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;
}
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