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