vfs: Add LSM hooks for the new mount API

Add LSM hooks for use by the new mount API and filesystem context code.
This includes:

 (1) Hooks to handle allocation, duplication and freeing of the security
     record attached to a filesystem context.

 (2) A hook to snoop source specifications.  There may be multiple of these
     if the filesystem supports it.  They will to be local files/devices if
     fs_context::source_is_dev is true and will be something else, possibly
     remote server specifications, if false.

 (3) A hook to snoop superblock configuration options in key[=val] form.
     If the LSM decides it wants to handle it, it can suppress the option
     being passed to the filesystem.  Note that 'val' may include commas
     and binary data with the fsopen patch.

 (4) A hook to perform validation and allocation after the configuration
     has been done but before the superblock is allocated and set up.

 (5) A hook to transfer the security from the context to a newly created
     superblock.

 (6) A hook to rule on whether a path point can be used as a mountpoint.

These are intended to replace:

	security_sb_copy_data
	security_sb_kern_mount
	security_sb_mount
	security_sb_set_mnt_opts
	security_sb_clone_mnt_opts
	security_sb_parse_opts_str

[AV -- some of the methods being replaced are already gone, some of the
methods are not added for the lack of need]

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-security-module@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index dbfb5a66babb..1cc4d7a3d6fa 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -53,6 +53,9 @@ struct msg_msg;
 struct xattr;
 struct xfrm_sec_ctx;
 struct mm_struct;
+struct fs_context;
+struct fs_parameter;
+enum fs_value_type;
 
 /* If capable should audit the security request */
 #define SECURITY_CAP_NOAUDIT 0
@@ -220,6 +223,7 @@ int security_bprm_set_creds(struct linux_binprm *bprm);
 int security_bprm_check(struct linux_binprm *bprm);
 void security_bprm_committing_creds(struct linux_binprm *bprm);
 void security_bprm_committed_creds(struct linux_binprm *bprm);
+int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param);
 int security_sb_alloc(struct super_block *sb);
 void security_sb_free(struct super_block *sb);
 void security_free_mnt_opts(void **mnt_opts);
@@ -517,6 +521,12 @@ static inline void security_bprm_committed_creds(struct linux_binprm *bprm)
 {
 }
 
+static inline int security_fs_context_parse_param(struct fs_context *fc,
+						  struct fs_parameter *param)
+{
+	return -ENOPARAM;
+}
+
 static inline int security_sb_alloc(struct super_block *sb)
 {
 	return 0;