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

3 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index e446ab97ee0c..2bf477f86eb1 100644
--- a/include/linux/kernfs.h
+++ b/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; }
 
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index a240a3fc5fc4..f7e55d0d2672 100644
--- a/include/linux/lsm_hooks.h
+++ b/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;
diff --git a/include/linux/security.h b/include/linux/security.h
index 49f2685324b0..d543293216b9 100644
--- a/include/linux/security.h
+++ b/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;