Changes to mdp:
Add support for devtmpfs, required by modern Linux distributions.
Add MLS support, with sample sensitivities, categories, and constraints.
Generate fs_use and genfscon rules based on kernel configuration.
Update list of filesystem types for fs_use and genfscon rules.
Use object_r for object contexts.
Changes to install_policy.sh:
Bail immediately on any errors.
Provide more helpful error messages when unable to find userspace tools.
Refuse to run if SELinux is already enabled.
Unconditionally move aside /etc/selinux/config and create a new one.
Build policy with -U allow so that userspace object managers do not break.
Build policy with MLS enabled by default.
Add default seusers mapping and failsafe context for use by
pam_selinux / libselinux.
Set to permissive mode rather than enforcing to permit initial autorelabel.
Update the list of filesystem types to be relabeled.
Create /.autorelabel to trigger an autorelabel on reboot.
Drop broken attempt to relabel the /dev mountpoint directory.
Signed-off-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
---
scripts/selinux/install_policy.sh | 82 ++++++++-------
scripts/selinux/mdp/mdp.c | 164 +++++++++++++++++++++++++-----
2 files changed, 183 insertions(+), 63 deletions(-)
diff --git a/scripts/selinux/install_policy.sh b/scripts/selinux/install_policy.sh
index 0b86c47baf7d..09eab4d0da5c 100755
--- a/scripts/selinux/install_policy.sh
+++ b/scripts/selinux/install_policy.sh
@@ -1,30 +1,51 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
+set -e
if [ `id -u` -ne 0 ]; then
echo "$0: must be root to install the selinux policy"
exit 1
fi
+
SF=`which setfiles`
if [ $? -eq 1 ]; then
- if [ -f /sbin/setfiles ]; then
- SF="/usr/setfiles"
- else
- echo "no selinux tools installed: setfiles"
- exit 1
- fi
+ echo "Could not find setfiles"
+ echo "Do you have policycoreutils installed?"
+ exit 1
fi
-cd mdp
-
CP=`which checkpolicy`
+if [ $? -eq 1 ]; then
+ echo "Could not find checkpolicy"
+ echo "Do you have checkpolicy installed?"
+ exit 1
+fi
VERS=`$CP -V | awk '{print $1}'`
-./mdp policy.conf file_contexts
-$CP -o policy.$VERS policy.conf
+ENABLED=`which selinuxenabled`
+if [ $? -eq 1 ]; then
+ echo "Could not find selinuxenabled"
+ echo "Do you have libselinux-utils installed?"
+ exit 1
+fi
+
+if selinuxenabled; then
+ echo "SELinux is already enabled"
+ echo "This prevents safely relabeling all files."
+ echo "Boot with selinux=0 on the kernel command-line or"
+ echo "SELINUX=disabled in /etc/selinux/config."
+ exit 1
+fi
+
+cd mdp
+./mdp -m policy.conf file_contexts
+$CP -U allow -M -o policy.$VERS policy.conf
mkdir -p /etc/selinux/dummy/policy
mkdir -p /etc/selinux/dummy/contexts/files
+echo "__default__:user_u" > /etc/selinux/dummy/seusers
+echo "base_r:base_t" > /etc/selinux/dummy/contexts/failsafe_context
+
cp file_contexts /etc/selinux/dummy/contexts/files
cp dbus_contexts /etc/selinux/dummy/contexts
cp policy.$VERS /etc/selinux/dummy/policy
@@ -33,37 +54,22 @@ FC_FILE=/etc/selinux/dummy/contexts/files/file_contexts
if [ ! -d /etc/selinux ]; then
mkdir -p /etc/selinux
fi
-if [ ! -f /etc/selinux/config ]; then
- cat > /etc/selinux/config << EOF
-SELINUX=enforcing
+if [ -f /etc/selinux/config ]; then
+ echo "/etc/selinux/config exists, moving to /etc/selinux/config.bak."
+ mv /etc/selinux/config /etc/selinux/config.bak
+fi
+echo "Creating new /etc/selinux/config for dummy policy."
+cat > /etc/selinux/config << EOF
+SELINUX=permissive
SELINUXTYPE=dummy
EOF
-else
- TYPE=`cat /etc/selinux/config | grep "^SELINUXTYPE" | tail -1 | awk -F= '{ print $2 '}`
- if [ "eq$TYPE" != "eqdummy" ]; then
- selinuxenabled
- if [ $? -eq 0 ]; then
- echo "SELinux already enabled with a non-dummy policy."
- echo "Exiting. Please install policy by hand if that"
- echo "is what you REALLY want."
- exit 1
- fi
- mv /etc/selinux/config /etc/selinux/config.mdpbak
- grep -v "^SELINUXTYPE" /etc/selinux/config.mdpbak >> /etc/selinux/config
- echo "SELINUXTYPE=dummy" >> /etc/selinux/config
- fi
-fi
cd /etc/selinux/dummy/contexts/files
-$SF file_contexts /
+$SF -F file_contexts /
-mounts=`cat /proc/$$/mounts | egrep "ext2|ext3|xfs|jfs|ext4|ext4dev|gfs2" | awk '{ print $2 '}`
-$SF file_contexts $mounts
+mounts=`cat /proc/$$/mounts | \
+ egrep "ext[234]|jfs|xfs|reiserfs|jffs2|gfs2|btrfs|f2fs|ocfs2" | \
+ awk '{ print $2 '}`
+$SF -F file_contexts $mounts
-
-dodev=`cat /proc/$$/mounts | grep "/dev "`
-if [ "eq$dodev" != "eq" ]; then
- mount --move /dev /mnt
- $SF file_contexts /dev
- mount --move /mnt /dev
-fi
+touch /.autorelabel
diff --git a/scripts/selinux/mdp/mdp.c b/scripts/selinux/mdp/mdp.c
index 073fe7537f6c..daad333c7252 100644
--- a/scripts/selinux/mdp/mdp.c
+++ b/scripts/selinux/mdp/mdp.c
@@ -33,6 +33,7 @@
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
+#include <linux/kconfig.h>
static void usage(char *name)
{
@@ -95,10 +96,31 @@ int main(int argc, char *argv[])
}
fprintf(fout, "\n");
- /* NOW PRINT OUT MLS STUFF */
+ /* print out mls declarations and constraints */
if (mls) {
- printf("MLS not yet implemented\n");
- exit(1);
+ 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");
+ }
}
/* types, roles, and allows */
@@ -108,34 +130,126 @@ int main(int argc, char *argv[])
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 };\n");
- fprintf(fout, "\n");
+ 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++)
- fprintf(fout, "sid %s user_u:base_r:base_t\n", initial_sid_to_string[i]);
+ fprintf(fout, "sid %s " SUBJUSERROLETYPE "%s\n",
+ initial_sid_to_string[i], mls ? ":" SYSTEMLOW : "");
fprintf(fout, "\n");
- fprintf(fout, "fs_use_xattr ext2 user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr ext3 user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr ext4 user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr jfs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr xfs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr reiserfs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr jffs2 user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_xattr gfs2 user_u:base_r:base_t;\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_EXT3_FS_SECURITY
+ FS_USE("xattr", "ext3");
+#endif
+#ifdef CONFIG_EXT4_FS_SECURITY
+ 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");
- fprintf(fout, "fs_use_task eventpollfs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_task pipefs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_task sockfs user_u:base_r:base_t;\n");
+ /*
+ * 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
- fprintf(fout, "fs_use_trans mqueue user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_trans devpts user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_trans hugetlbfs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_trans tmpfs user_u:base_r:base_t;\n");
- fprintf(fout, "fs_use_trans shm user_u:base_r:base_t;\n");
+#define GENFSCON(fstype, prefix) \
+ fprintf(fout, "genfscon %s %s " OBJUSERROLETYPE "%s\n", \
+ fstype, prefix, mls ? ":" SYSTEMLOW : "")
- fprintf(fout, "genfscon proc / user_u:base_r:base_t\n");
+ /*
+ * 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);
@@ -144,8 +258,8 @@ int main(int argc, char *argv[])
printf("Wrote policy, but cannot open %s for writing\n", ctxout);
usage(argv[0]);
}
- fprintf(fout, "/ user_u:base_r:base_t\n");
- fprintf(fout, "/.* user_u:base_r:base_t\n");
+ fprintf(fout, "/ " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
+ fprintf(fout, "/.* " OBJUSERROLETYPE "%s\n", mls ? ":" SYSTEMLOW : "");
fclose(fout);
return 0;
