Merge tag 'selinux-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "We've got a few SELinux patches for the v5.2 merge window, the
  highlights are below:

   - Add LSM hooks, and the SELinux implementation, for proper labeling
     of kernfs. While we are only including the SELinux implementation
     here, the rest of the LSM folks have given the hooks a thumbs-up.

   - Update the SELinux mdp (Make Dummy Policy) script to actually work
     on a modern system.

   - Disallow userspace to change the LSM credentials via
     /proc/self/attr when the task's credentials are already overridden.

     The change was made in procfs because all the LSM folks agreed this
     was the Right Thing To Do and duplicating it across each LSM was
     going to be annoying"

* tag 'selinux-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  proc: prevent changes to overridden credentials
  selinux: Check address length before reading address family
  kernfs: fix xattr name handling in LSM helpers
  MAINTAINERS: update SELinux file patterns
  selinux: avoid uninitialized variable warning
  selinux: remove useless assignments
  LSM: lsm_hooks.h - fix missing colon in docstring
  selinux: Make selinux_kernfs_init_security static
  kernfs: initialize security of newly created nodes
  selinux: implement the kernfs_init_security hook
  LSM: add new hook for kernfs node initialization
  kernfs: use simple_xattrs for security attributes
  selinux: try security xattr after genfs for kernfs filesystems
  kernfs: do not alloc iattrs in kernfs_xattr_get
  kernfs: clean up struct kernfs_iattrs
  scripts/selinux: fix build
  selinux: use kernel linux/socket.h for genheaders and mdp
  scripts/selinux: modernize mdp

MAINTAINERS

@@ -13994,7 +13994,7 @@ W:	https://selinuxproject.org
 W:	https://github.com/SELinuxProject
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux.git
 S:	Supported
-F:	include/linux/selinux*
+F:	include/uapi/linux/selinux_netlink.h
 F:	security/selinux/
 F:	scripts/selinux/
 F:	Documentation/admin-guide/LSM/SELinux.rst

fs/kernfs/dir.c

@@ -532,9 +532,6 @@ void kernfs_put(struct kernfs_node *kn)
 	kfree_const(kn->name);
 
 	if (kn->iattr) {
-		if (kn->iattr->ia_secdata)
-			security_release_secctx(kn->iattr->ia_secdata,
-						kn->iattr->ia_secdata_len);
 		simple_xattrs_free(&kn->iattr->xattrs);
 		kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
 	}
@@ -618,6 +615,7 @@ struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
 }
 
 static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
+					     struct kernfs_node *parent,
 					     const char *name, umode_t mode,
 					     kuid_t uid, kgid_t gid,
 					     unsigned flags)
@@ -673,6 +671,12 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
 			goto err_out3;
 	}
 
+	if (parent) {
+		ret = security_kernfs_init_security(parent, kn);
+		if (ret)
+			goto err_out3;
+	}
+
 	return kn;
 
  err_out3:
@@ -691,7 +695,7 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
 {
 	struct kernfs_node *kn;
 
-	kn = __kernfs_new_node(kernfs_root(parent),
+	kn = __kernfs_new_node(kernfs_root(parent), parent,
 			       name, mode, uid, gid, flags);
 	if (kn) {
 		kernfs_get(parent);
@@ -794,9 +798,8 @@ int kernfs_add_one(struct kernfs_node *kn)
 	/* Update timestamps on the parent */
 	ps_iattr = parent->iattr;
 	if (ps_iattr) {
-		struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
-		ktime_get_real_ts64(&ps_iattrs->ia_ctime);
-		ps_iattrs->ia_mtime = ps_iattrs->ia_ctime;
+		ktime_get_real_ts64(&ps_iattr->ia_ctime);
+		ps_iattr->ia_mtime = ps_iattr->ia_ctime;
 	}
 
 	mutex_unlock(&kernfs_mutex);
@@ -961,7 +964,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
 	INIT_LIST_HEAD(&root->supers);
 	root->next_generation = 1;
 
-	kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
+	kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO,
 			       GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
 			       KERNFS_DIR);
 	if (!kn) {
@@ -1328,9 +1331,8 @@ static void __kernfs_remove(struct kernfs_node *kn)
 
 			/* update timestamps on the parent */
 			if (ps_iattr) {
-				ktime_get_real_ts64(&ps_iattr->ia_iattr.ia_ctime);
-				ps_iattr->ia_iattr.ia_mtime =
-					ps_iattr->ia_iattr.ia_ctime;
+				ktime_get_real_ts64(&ps_iattr->ia_ctime);
+				ps_iattr->ia_mtime = ps_iattr->ia_ctime;
 			}
 
 			kernfs_put(pos);

fs/kernfs/inode.c

@@ -31,30 +31,27 @@ static const struct inode_operations kernfs_iops = {
 	.listxattr	= kernfs_iop_listxattr,
 };
 
-static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
+static struct kernfs_iattrs *__kernfs_iattrs(struct kernfs_node *kn, int alloc)
 {
 	static DEFINE_MUTEX(iattr_mutex);
 	struct kernfs_iattrs *ret;
-	struct iattr *iattrs;
 
 	mutex_lock(&iattr_mutex);
 
-	if (kn->iattr)
+	if (kn->iattr || !alloc)
 		goto out_unlock;
 
 	kn->iattr = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
 	if (!kn->iattr)
 		goto out_unlock;
-	iattrs = &kn->iattr->ia_iattr;
 
 	/* assign default attributes */
-	iattrs->ia_mode = kn->mode;
-	iattrs->ia_uid = GLOBAL_ROOT_UID;
-	iattrs->ia_gid = GLOBAL_ROOT_GID;
+	kn->iattr->ia_uid = GLOBAL_ROOT_UID;
+	kn->iattr->ia_gid = GLOBAL_ROOT_GID;
 
-	ktime_get_real_ts64(&iattrs->ia_atime);
-	iattrs->ia_mtime = iattrs->ia_atime;
-	iattrs->ia_ctime = iattrs->ia_atime;
+	ktime_get_real_ts64(&kn->iattr->ia_atime);
+	kn->iattr->ia_mtime = kn->iattr->ia_atime;
+	kn->iattr->ia_ctime = kn->iattr->ia_atime;
 
 	simple_xattrs_init(&kn->iattr->xattrs);
 out_unlock:
@@ -63,32 +60,37 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
 	return ret;
 }
 
+static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
+{
+	return __kernfs_iattrs(kn, 1);
+}
+
+static struct kernfs_iattrs *kernfs_iattrs_noalloc(struct kernfs_node *kn)
+{
+	return __kernfs_iattrs(kn, 0);
+}
+
 int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
 {
 	struct kernfs_iattrs *attrs;
-	struct iattr *iattrs;
 	unsigned int ia_valid = iattr->ia_valid;
 
 	attrs = kernfs_iattrs(kn);
 	if (!attrs)
 		return -ENOMEM;
 
-	iattrs = &attrs->ia_iattr;
-
 	if (ia_valid & ATTR_UID)
-		iattrs->ia_uid = iattr->ia_uid;
+		attrs->ia_uid = iattr->ia_uid;
 	if (ia_valid & ATTR_GID)
-		iattrs->ia_gid = iattr->ia_gid;
+		attrs->ia_gid = iattr->ia_gid;
 	if (ia_valid & ATTR_ATIME)
-		iattrs->ia_atime = iattr->ia_atime;
+		attrs->ia_atime = iattr->ia_atime;
 	if (ia_valid & ATTR_MTIME)
-		iattrs->ia_mtime = iattr->ia_mtime;
+		attrs->ia_mtime = iattr->ia_mtime;
 	if (ia_valid & ATTR_CTIME)
-		iattrs->ia_ctime = iattr->ia_ctime;
-	if (ia_valid & ATTR_MODE) {
-		umode_t mode = iattr->ia_mode;
-		iattrs->ia_mode = kn->mode = mode;
-	}
+		attrs->ia_ctime = iattr->ia_ctime;
+	if (ia_valid & ATTR_MODE)
+		kn->mode = iattr->ia_mode;
 	return 0;
 }
 
@@ -135,23 +137,6 @@ int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
 	return error;
 }
 
-static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata,
-				  u32 *secdata_len)
-{
-	void *old_secdata;
-	size_t old_secdata_len;
-
-	old_secdata = attrs->ia_secdata;
-	old_secdata_len = attrs->ia_secdata_len;
-
-	attrs->ia_secdata = *secdata;
-	attrs->ia_secdata_len = *secdata_len;
-
-	*secdata = old_secdata;
-	*secdata_len = old_secdata_len;
-	return 0;
-}
-
 ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
 {
 	struct kernfs_node *kn = kernfs_dentry_node(dentry);
@@ -171,14 +156,15 @@ static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
 		inode->i_ctime = current_time(inode);
 }
 
-static inline void set_inode_attr(struct inode *inode, struct iattr *iattr)
+static inline void set_inode_attr(struct inode *inode,
+				  struct kernfs_iattrs *attrs)
 {
 	struct super_block *sb = inode->i_sb;
-	inode->i_uid = iattr->ia_uid;
-	inode->i_gid = iattr->ia_gid;
-	inode->i_atime = timespec64_trunc(iattr->ia_atime, sb->s_time_gran);
-	inode->i_mtime = timespec64_trunc(iattr->ia_mtime, sb->s_time_gran);
-	inode->i_ctime = timespec64_trunc(iattr->ia_ctime, sb->s_time_gran);
+	inode->i_uid = attrs->ia_uid;
+	inode->i_gid = attrs->ia_gid;
+	inode->i_atime = timespec64_trunc(attrs->ia_atime, sb->s_time_gran);
+	inode->i_mtime = timespec64_trunc(attrs->ia_mtime, sb->s_time_gran);
+	inode->i_ctime = timespec64_trunc(attrs->ia_ctime, sb->s_time_gran);
 }
 
 static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
@@ -186,15 +172,12 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
 	struct kernfs_iattrs *attrs = kn->iattr;
 
 	inode->i_mode = kn->mode;
-	if (attrs) {
+	if (attrs)
 		/*
 		 * kernfs_node has non-default attributes get them from
 		 * persistent copy in kernfs_node.
 		 */
-		set_inode_attr(inode, &attrs->ia_iattr);
-		security_inode_notifysecctx(inode, attrs->ia_secdata,
-					    attrs->ia_secdata_len);
-	}
+		set_inode_attr(inode, attrs);
 
 	if (kernfs_type(kn) == KERNFS_DIR)
 		set_nlink(inode, kn->dir.subdirs + 2);
@@ -305,78 +288,57 @@ int kernfs_iop_permission(struct inode *inode, int mask)
 	return generic_permission(inode, mask);
 }
 
-static int kernfs_xattr_get(const struct xattr_handler *handler,
-			    struct dentry *unused, struct inode *inode,
-			    const char *suffix, void *value, size_t size)
+int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
+		     void *value, size_t size)
 {
-	const char *name = xattr_full_name(handler, suffix);
-	struct kernfs_node *kn = inode->i_private;
-	struct kernfs_iattrs *attrs;
-
-	attrs = kernfs_iattrs(kn);
+	struct kernfs_iattrs *attrs = kernfs_iattrs_noalloc(kn);
 	if (!attrs)
-		return -ENOMEM;
+		return -ENODATA;
 
 	return simple_xattr_get(&attrs->xattrs, name, value, size);
 }
 
-static int kernfs_xattr_set(const struct xattr_handler *handler,
-			    struct dentry *unused, struct inode *inode,
-			    const char *suffix, const void *value,
-			    size_t size, int flags)
+int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
+		     const void *value, size_t size, int flags)
 {
-	const char *name = xattr_full_name(handler, suffix);
-	struct kernfs_node *kn = inode->i_private;
-	struct kernfs_iattrs *attrs;
-
-	attrs = kernfs_iattrs(kn);
+	struct kernfs_iattrs *attrs = kernfs_iattrs(kn);
 	if (!attrs)
 		return -ENOMEM;
 
 	return simple_xattr_set(&attrs->xattrs, name, value, size, flags);
 }
 
-static const struct xattr_handler kernfs_trusted_xattr_handler = {
-	.prefix = XATTR_TRUSTED_PREFIX,
-	.get = kernfs_xattr_get,
-	.set = kernfs_xattr_set,
-};
-
-static int kernfs_security_xattr_set(const struct xattr_handler *handler,
-				     struct dentry *unused, struct inode *inode,
-				     const char *suffix, const void *value,
-				     size_t size, int flags)
+static int kernfs_vfs_xattr_get(const struct xattr_handler *handler,
+				struct dentry *unused, struct inode *inode,
+				const char *suffix, void *value, size_t size)
 {
+	const char *name = xattr_full_name(handler, suffix);
 	struct kernfs_node *kn = inode->i_private;
-	struct kernfs_iattrs *attrs;
-	void *secdata;
-	u32 secdata_len = 0;
-	int error;
-
-	attrs = kernfs_iattrs(kn);
-	if (!attrs)
-		return -ENOMEM;
 
-	error = security_inode_setsecurity(inode, suffix, value, size, flags);
-	if (error)
-		return error;
-	error = security_inode_getsecctx(inode, &secdata, &secdata_len);
-	if (error)
-		return error;
+	return kernfs_xattr_get(kn, name, value, size);
+}
 
-	mutex_lock(&kernfs_mutex);
-	error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len);
-	mutex_unlock(&kernfs_mutex);
+static int kernfs_vfs_xattr_set(const struct xattr_handler *handler,
+				struct dentry *unused, struct inode *inode,
+				const char *suffix, const void *value,
+				size_t size, int flags)
+{
+	const char *name = xattr_full_name(handler, suffix);
+	struct kernfs_node *kn = inode->i_private;
 
-	if (secdata)
-		security_release_secctx(secdata, secdata_len);
-	return error;
+	return kernfs_xattr_set(kn, name, value, size, flags);
 }
 
+static const struct xattr_handler kernfs_trusted_xattr_handler = {
+	.prefix = XATTR_TRUSTED_PREFIX,
+	.get = kernfs_vfs_xattr_get,
+	.set = kernfs_vfs_xattr_set,
+};
+
 static const struct xattr_handler kernfs_security_xattr_handler = {
 	.prefix = XATTR_SECURITY_PREFIX,
-	.get = kernfs_xattr_get,
-	.set = kernfs_security_xattr_set,
+	.get = kernfs_vfs_xattr_get,
+	.set = kernfs_vfs_xattr_set,
 };
 
 const struct xattr_handler *kernfs_xattr_handlers[] = {

fs/kernfs/kernfs-internal.h

@@ -20,9 +20,11 @@
 #include <linux/fs_context.h>
 
 struct kernfs_iattrs {
-	struct iattr		ia_iattr;
-	void			*ia_secdata;
-	u32			ia_secdata_len;
+	kuid_t			ia_uid;
+	kgid_t			ia_gid;
+	struct timespec64	ia_atime;
+	struct timespec64	ia_mtime;
+	struct timespec64	ia_ctime;
 
 	struct simple_xattrs	xattrs;
 };

fs/kernfs/symlink.c

@@ -33,8 +33,8 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
 	kgid_t gid = GLOBAL_ROOT_GID;
 
 	if (target->iattr) {
-		uid = target->iattr->ia_iattr.ia_uid;
-		gid = target->iattr->ia_iattr.ia_gid;
+		uid = target->iattr->ia_uid;
+		gid = target->iattr->ia_gid;
 	}
 
 	kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, uid, gid,

fs/proc/base.c

@@ -2535,6 +2535,11 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 		rcu_read_unlock();
 		return -EACCES;
 	}
+	/* Prevent changes to overridden credentials. */
+	if (current_cred() != current_real_cred()) {
+		rcu_read_unlock();
+		return -EBUSY;
+	}
 	rcu_read_unlock();
 
 	if (count > PAGE_SIZE)

include/linux/kernfs.h

@@ -371,6 +371,11 @@ __poll_t kernfs_generic_poll(struct kernfs_open_file *of,
 			     struct poll_table_struct *pt);
 void kernfs_notify(struct kernfs_node *kn);
 
+int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
+		     void *value, size_t size);
+int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
+		     const void *value, size_t size, int flags);
+
 const void *kernfs_super_ns(struct super_block *sb);
 int kernfs_get_tree(struct fs_context *fc);
 void kernfs_free_fs_context(struct fs_context *fc);
@@ -473,6 +478,14 @@ static inline int kernfs_setattr(struct kernfs_node *kn,
 
 static inline void kernfs_notify(struct kernfs_node *kn) { }
 
+static inline int kernfs_xattr_get(struct kernfs_node *kn, const char *name,
+				   void *value, size_t size)
+{ return -ENOSYS; }
+
+static inline int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
+				   const void *value, size_t size, int flags)
+{ return -ENOSYS; }
+
 static inline const void *kernfs_super_ns(struct super_block *sb)
 { return NULL; }
 

include/linux/lsm_hooks.h

@@ -445,6 +445,15 @@
  *	to abort the copy up. Note that the caller is responsible for reading
  *	and writing the xattrs as this hook is merely a filter.
  *
+ * Security hooks for kernfs node operations
+ *
+ * @kernfs_init_security:
+ *	Initialize the security context of a newly created kernfs node based
+ *	on its own and its parent's attributes.
+ *
+ *	@kn_dir the parent kernfs node
+ *	@kn the new child kernfs node
+ *
  * Security hooks for file operations
  *
  * @file_permission:
@@ -1570,6 +1579,9 @@ union security_list_options {
 	int (*inode_copy_up)(struct dentry *src, struct cred **new);
 	int (*inode_copy_up_xattr)(const char *name);
 
+	int (*kernfs_init_security)(struct kernfs_node *kn_dir,
+				    struct kernfs_node *kn);
+
 	int (*file_permission)(struct file *file, int mask);
 	int (*file_alloc_security)(struct file *file);
 	void (*file_free_security)(struct file *file);
@@ -1871,6 +1883,7 @@ struct security_hook_heads {
 	struct hlist_head inode_getsecid;
 	struct hlist_head inode_copy_up;
 	struct hlist_head inode_copy_up_xattr;
+	struct hlist_head kernfs_init_security;
 	struct hlist_head file_permission;
 	struct hlist_head file_alloc_security;
 	struct hlist_head file_free_security;

include/linux/security.h

@@ -51,6 +51,7 @@ struct fown_struct;
 struct file_operations;
 struct msg_msg;
 struct xattr;
+struct kernfs_node;
 struct xfrm_sec_ctx;
 struct mm_struct;
 struct fs_context;
@@ -299,6 +300,8 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer
 void security_inode_getsecid(struct inode *inode, u32 *secid);
 int security_inode_copy_up(struct dentry *src, struct cred **new);
 int security_inode_copy_up_xattr(const char *name);
+int security_kernfs_init_security(struct kernfs_node *kn_dir,
+				  struct kernfs_node *kn);
 int security_file_permission(struct file *file, int mask);
 int security_file_alloc(struct file *file);
 void security_file_free(struct file *file);
@@ -801,6 +804,12 @@ static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
 	return 0;
 }
 
+static inline int security_kernfs_init_security(struct kernfs_node *kn_dir,
+						struct kernfs_node *kn)
+{
+	return 0;
+}
+
 static inline int security_inode_copy_up_xattr(const char *name)
 {
 	return -EOPNOTSUPP;

scripts/selinux/install_policy.sh

 #!/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:s0" > /etc/selinux/dummy/seusers
+echo "base_r:base_t:s0" > /etc/selinux/dummy/contexts/failsafe_context
+echo "base_r:base_t:s0 base_r:base_t:s0" > /etc/selinux/dummy/default_contexts
+cat > /etc/selinux/dummy/contexts/x_contexts <<EOF
+client * user_u:base_r:base_t:s0
+property * user_u:object_r:base_t:s0
+extension * user_u:object_r:base_t:s0
+selection * user_u:object_r:base_t:s0
+event * user_u:object_r:base_t:s0
+EOF
+touch /etc/selinux/dummy/contexts/virtual_domain_context
+touch /etc/selinux/dummy/contexts/virtual_image_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 +64,22 @@ 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
+echo "-F" > /.autorelabel

scripts/selinux/mdp/Makefile

@@ -2,7 +2,7 @@
 hostprogs-y	:= mdp
 HOST_EXTRACFLAGS += \
 	-I$(srctree)/include/uapi -I$(srctree)/include \
-	-I$(srctree)/security/selinux/include
+	-I$(srctree)/security/selinux/include -I$(objtree)/include
 
 always		:= $(hostprogs-y)
 clean-files	:= policy.* file_contexts

scripts/selinux/mdp/mdp.c

@@ -32,6 +32,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
+#include <linux/kconfig.h>
 
 static void usage(char *name)
 {
@@ -94,10 +95,31 @@ 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 */
@@ -107,34 +129,127 @@ 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_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");
 
-	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);
 
@@ -143,8 +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;

security/security.c

@@ -1318,6 +1318,12 @@ int security_inode_copy_up_xattr(const char *name)
 }
 EXPORT_SYMBOL(security_inode_copy_up_xattr);
 
+int security_kernfs_init_security(struct kernfs_node *kn_dir,
+				  struct kernfs_node *kn)
+{
+	return call_int_hook(kernfs_init_security, 0, kn_dir, kn);
+}
+
 int security_file_permission(struct file *file, int mask)
 {
 	int ret;

security/selinux/hooks.c

@@ -89,6 +89,8 @@
 #include <linux/msg.h>
 #include <linux/shm.h>
 #include <linux/bpf.h>
+#include <linux/kernfs.h>
+#include <linux/stringhash.h>	/* for hashlen_string() */
 #include <uapi/linux/mount.h>
 
 #include "avc.h"
@@ -751,11 +753,13 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 
 	if (!strcmp(sb->s_type->name, "debugfs") ||
 	    !strcmp(sb->s_type->name, "tracefs") ||
-	    !strcmp(sb->s_type->name, "sysfs") ||
-	    !strcmp(sb->s_type->name, "pstore") ||
+	    !strcmp(sb->s_type->name, "pstore"))
+		sbsec->flags |= SE_SBGENFS;
+
+	if (!strcmp(sb->s_type->name, "sysfs") ||
 	    !strcmp(sb->s_type->name, "cgroup") ||
 	    !strcmp(sb->s_type->name, "cgroup2"))
-		sbsec->flags |= SE_SBGENFS;
+		sbsec->flags |= SE_SBGENFS | SE_SBGENFS_XATTR;
 
 	if (!sbsec->behavior) {
 		/*
@@ -1354,6 +1358,67 @@ static int selinux_genfs_get_sid(struct dentry *dentry,
 	return rc;
 }
 
+static int inode_doinit_use_xattr(struct inode *inode, struct dentry *dentry,
+				  u32 def_sid, u32 *sid)
+{
+#define INITCONTEXTLEN 255
+	char *context;
+	unsigned int len;
+	int rc;
+
+	len = INITCONTEXTLEN;
+	context = kmalloc(len + 1, GFP_NOFS);
+	if (!context)
+		return -ENOMEM;
+
+	context[len] = '\0';
+	rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
+	if (rc == -ERANGE) {
+		kfree(context);
+
+		/* Need a larger buffer.  Query for the right size. */
+		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
+		if (rc < 0)
+			return rc;
+
+		len = rc;
+		context = kmalloc(len + 1, GFP_NOFS);
+		if (!context)
+			return -ENOMEM;
+
+		context[len] = '\0';
+		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX,
+				    context, len);
+	}
+	if (rc < 0) {
+		kfree(context);
+		if (rc != -ENODATA) {
+			pr_warn("SELinux: %s:  getxattr returned %d for dev=%s ino=%ld\n",
+				__func__, -rc, inode->i_sb->s_id, inode->i_ino);
+			return rc;
+		}
+		*sid = def_sid;
+		return 0;
+	}
+
+	rc = security_context_to_sid_default(&selinux_state, context, rc, sid,
+					     def_sid, GFP_NOFS);
+	if (rc) {
+		char *dev = inode->i_sb->s_id;
+		unsigned long ino = inode->i_ino;
+
+		if (rc == -EINVAL) {
+			pr_notice_ratelimited("SELinux: inode=%lu on dev=%s was found to have an invalid context=%s.  This indicates you may need to relabel the inode or the filesystem in question.\n",
+					      ino, dev, context);
+		} else {
+			pr_warn("SELinux: %s:  context_to_sid(%s) returned %d for dev=%s ino=%ld\n",
+				__func__, context, -rc, dev, ino);
+		}
+	}
+	kfree(context);
+	return 0;
+}
+
 /* The inode's security attributes must be initialized before first use. */
 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
 {
@@ -1362,9 +1427,6 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 	u32 task_sid, sid = 0;
 	u16 sclass;
 	struct dentry *dentry;
-#define INITCONTEXTLEN 255
-	char *context = NULL;
-	unsigned len = 0;
 	int rc = 0;
 
 	if (isec->initialized == LABEL_INITIALIZED)
@@ -1432,72 +1494,11 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 			goto out;
 		}
 
-		len = INITCONTEXTLEN;
-		context = kmalloc(len+1, GFP_NOFS);
-		if (!context) {
-			rc = -ENOMEM;
-			dput(dentry);
-			goto out;
-		}
-		context[len] = '\0';
-		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
-		if (rc == -ERANGE) {
-			kfree(context);
-
-			/* Need a larger buffer.  Query for the right size. */
-			rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
-			if (rc < 0) {
-				dput(dentry);
-				goto out;
-			}
-			len = rc;
-			context = kmalloc(len+1, GFP_NOFS);
-			if (!context) {
-				rc = -ENOMEM;
-				dput(dentry);
-				goto out;
-			}
-			context[len] = '\0';
-			rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
-		}
+		rc = inode_doinit_use_xattr(inode, dentry, sbsec->def_sid,
+					    &sid);
 		dput(dentry);
-		if (rc < 0) {
-			if (rc != -ENODATA) {
-				pr_warn("SELinux: %s:  getxattr returned "
-				       "%d for dev=%s ino=%ld\n", __func__,
-				       -rc, inode->i_sb->s_id, inode->i_ino);
-				kfree(context);
-				goto out;
-			}
-			/* Map ENODATA to the default file SID */
-			sid = sbsec->def_sid;
-			rc = 0;
-		} else {
-			rc = security_context_to_sid_default(&selinux_state,
-							     context, rc, &sid,
-							     sbsec->def_sid,
-							     GFP_NOFS);
-			if (rc) {
-				char *dev = inode->i_sb->s_id;
-				unsigned long ino = inode->i_ino;
-
-				if (rc == -EINVAL) {
-					if (printk_ratelimit())
-						pr_notice("SELinux: inode=%lu on dev=%s was found to have an invalid "
-							"context=%s.  This indicates you may need to relabel the inode or the "
-							"filesystem in question.\n", ino, dev, context);
-				} else {
-					pr_warn("SELinux: %s:  context_to_sid(%s) "
-					       "returned %d for dev=%s ino=%ld\n",
-					       __func__, context, -rc, dev, ino);
-				}
-				kfree(context);
-				/* Leave with the unlabeled SID */
-				rc = 0;
-				break;
-			}
-		}
-		kfree(context);
+		if (rc)
+			goto out;
 		break;
 	case SECURITY_FS_USE_TASK:
 		sid = task_sid;
@@ -1548,9 +1549,21 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 				goto out;
 			rc = selinux_genfs_get_sid(dentry, sclass,
 						   sbsec->flags, &sid);
-			dput(dentry);
-			if (rc)
+			if (rc) {
+				dput(dentry);
 				goto out;
+			}
+
+			if ((sbsec->flags & SE_SBGENFS_XATTR) &&
+			    (inode->i_opflags & IOP_XATTR)) {
+				rc = inode_doinit_use_xattr(inode, dentry,
+							    sid, &sid);
+				if (rc) {
+					dput(dentry);
+					goto out;
+				}
+			}
+			dput(dentry);
 		}
 		break;
 	}
@@ -3371,6 +3384,67 @@ static int selinux_inode_copy_up_xattr(const char *name)
 	return -EOPNOTSUPP;
 }
 
+/* kernfs node operations */
+
+static int selinux_kernfs_init_security(struct kernfs_node *kn_dir,
+					struct kernfs_node *kn)
+{
+	const struct task_security_struct *tsec = current_security();
+	u32 parent_sid, newsid, clen;
+	int rc;
+	char *context;
+
+	rc = kernfs_xattr_get(kn_dir, XATTR_NAME_SELINUX, NULL, 0);
+	if (rc == -ENODATA)
+		return 0;
+	else if (rc < 0)
+		return rc;
+
+	clen = (u32)rc;
+	context = kmalloc(clen, GFP_KERNEL);
+	if (!context)
+		return -ENOMEM;
+
+	rc = kernfs_xattr_get(kn_dir, XATTR_NAME_SELINUX, context, clen);
+	if (rc < 0) {
+		kfree(context);
+		return rc;
+	}
+
+	rc = security_context_to_sid(&selinux_state, context, clen, &parent_sid,
+				     GFP_KERNEL);
+	kfree(context);
+	if (rc)
+		return rc;
+
+	if (tsec->create_sid) {
+		newsid = tsec->create_sid;
+	} else {
+		u16 secclass = inode_mode_to_security_class(kn->mode);
+		struct qstr q;
+
+		q.name = kn->name;
+		q.hash_len = hashlen_string(kn_dir, kn->name);
+
+		rc = security_transition_sid(&selinux_state, tsec->sid,
+					     parent_sid, secclass, &q,
+					     &newsid);
+		if (rc)
+			return rc;
+	}
+
+	rc = security_sid_to_context_force(&selinux_state, newsid,
+					   &context, &clen);
+	if (rc)
+		return rc;
+
+	rc = kernfs_xattr_set(kn, XATTR_NAME_SELINUX, context, clen,
+			      XATTR_CREATE);
+	kfree(context);
+	return rc;
+}
+
+
 /* file security operations */
 
 static int selinux_revalidate_file_permission(struct file *file, int mask)
@@ -4438,7 +4512,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
 		struct lsm_network_audit net = {0,};
 		struct sockaddr_in *addr4 = NULL;
 		struct sockaddr_in6 *addr6 = NULL;
-		u16 family_sa = address->sa_family;
+		u16 family_sa;
 		unsigned short snum;
 		u32 sid, node_perm;
 
@@ -4448,6 +4522,9 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
 		 * need to check address->sa_family as it is possible to have
 		 * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
 		 */
+		if (addrlen < offsetofend(struct sockaddr, sa_family))
+			return -EINVAL;
+		family_sa = address->sa_family;
 		switch (family_sa) {
 		case AF_UNSPEC:
 		case AF_INET:
@@ -4580,6 +4657,8 @@ static int selinux_socket_connect_helper(struct socket *sock,
 		 * need to check address->sa_family as it is possible to have
 		 * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
 		 */
+		if (addrlen < offsetofend(struct sockaddr, sa_family))
+			return -EINVAL;
 		switch (address->sa_family) {
 		case AF_INET:
 			addr4 = (struct sockaddr_in *)address;
@@ -6719,6 +6798,8 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(inode_copy_up, selinux_inode_copy_up),
 	LSM_HOOK_INIT(inode_copy_up_xattr, selinux_inode_copy_up_xattr),
 
+	LSM_HOOK_INIT(kernfs_init_security, selinux_kernfs_init_security),
+
 	LSM_HOOK_INIT(file_permission, selinux_file_permission),
 	LSM_HOOK_INIT(file_alloc_security, selinux_file_alloc_security),
 	LSM_HOOK_INIT(file_ioctl, selinux_file_ioctl),

security/selinux/include/security.h

@@ -58,6 +58,7 @@
 #define SE_SBINITIALIZED	0x0100
 #define SE_SBPROC		0x0200
 #define SE_SBGENFS		0x0400
+#define SE_SBGENFS_XATTR	0x0800
 
 #define CONTEXT_STR	"context"
 #define FSCONTEXT_STR	"fscontext"

security/selinux/netlabel.c

@@ -288,11 +288,8 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
 	int rc;
 	struct netlbl_lsm_secattr secattr;
 	struct sk_security_struct *sksec = ep->base.sk->sk_security;
-	struct sockaddr *addr;
 	struct sockaddr_in addr4;
-#if IS_ENABLED(CONFIG_IPV6)
 	struct sockaddr_in6 addr6;
-#endif
 
 	if (ep->base.sk->sk_family != PF_INET &&
 				ep->base.sk->sk_family != PF_INET6)
@@ -310,16 +307,15 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
 	if (ip_hdr(skb)->version == 4) {
 		addr4.sin_family = AF_INET;
 		addr4.sin_addr.s_addr = ip_hdr(skb)->saddr;
-		addr = (struct sockaddr *)&addr4;
-#if IS_ENABLED(CONFIG_IPV6)
-	} else {
+		rc = netlbl_conn_setattr(ep->base.sk, (void *)&addr4, &secattr);
+	} else if (IS_ENABLED(CONFIG_IPV6) && ip_hdr(skb)->version == 6) {
 		addr6.sin6_family = AF_INET6;
 		addr6.sin6_addr = ipv6_hdr(skb)->saddr;
-		addr = (struct sockaddr *)&addr6;
-#endif
+		rc = netlbl_conn_setattr(ep->base.sk, (void *)&addr6, &secattr);
+	} else {
+		rc = -EAFNOSUPPORT;
 	}
 
-	rc = netlbl_conn_setattr(ep->base.sk, addr, &secattr);
 	if (rc == 0)
 		sksec->nlbl_state = NLBL_LABELED;
 

security/selinux/ss/services.c

@@ -1318,14 +1318,11 @@ static int security_sid_to_context_core(struct selinux_state *state,
 		rc = -EINVAL;
 		goto out_unlock;
 	}
-	if (only_invalid && !context->len) {
-		scontext = NULL;
-		scontext_len = 0;
+	if (only_invalid && !context->len)
 		rc = 0;
-	} else {
+	else
 		rc = context_struct_to_string(policydb, context, scontext,
 					      scontext_len);
-	}
 out_unlock:
 	read_unlock(&state->ss->policy_rwlock);
 out: