TOMOYO: Add mount restriction.

mount(2) has three string and one numeric parameters.
Split mount restriction code from security/tomoyo/file.c .

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

7 files changed, 469 insertions, 11 deletions

diff --git a/security/tomoyo/Makefile b/security/tomoyo/Makefile
index 4d1b5af4f1f7..d7befab40eff 100644
--- a/security/tomoyo/Makefile
+++ b/security/tomoyo/Makefile
@@ -1 +1 @@
-obj-y = common.o realpath.o tomoyo.o domain.o file.o gc.o path_group.o number_group.o
+obj-y = common.o realpath.o tomoyo.o domain.o file.o gc.o path_group.o number_group.o mount.o
diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 0706b175fdb1..0c6f9a5c37a5 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -1075,6 +1075,10 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r)
 				if (perm & (1 << i))
 					count++;
 			break;
+		case TOMOYO_TYPE_MOUNT_ACL:
+			if (!container_of(ptr, struct tomoyo_mount_acl, head)->
+			    is_deleted)
+				count++;
 		}
 	}
 	if (count < tomoyo_check_flags(domain, TOMOYO_MAX_ACCEPT_ENTRY))
@@ -1576,6 +1580,8 @@ static int tomoyo_write_domain_policy(struct tomoyo_io_buffer *head)
 		domain->ignore_global_allow_read = !is_delete;
 		return 0;
 	}
+        if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_ALLOW_MOUNT))
+                return tomoyo_write_mount_policy(data, domain, is_delete);
 	return tomoyo_write_file_policy(data, domain, is_delete);
 }
 
@@ -1721,6 +1727,30 @@ static bool tomoyo_print_path_number3_acl(struct tomoyo_io_buffer *head,
 }
 
 /**
+ * tomoyo_print_mount_acl - Print a mount ACL entry.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ * @ptr:  Pointer to "struct tomoyo_mount_acl".
+ *
+ * Returns true on success, false otherwise.
+ */
+static bool tomoyo_print_mount_acl(struct tomoyo_io_buffer *head,
+				   struct tomoyo_mount_acl *ptr)
+{
+	const int pos = head->read_avail;
+	if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_ALLOW_MOUNT) ||
+	    !tomoyo_print_name_union(head, &ptr->dev_name) ||
+	    !tomoyo_print_name_union(head, &ptr->dir_name) ||
+	    !tomoyo_print_name_union(head, &ptr->fs_type) ||
+	    !tomoyo_print_number_union(head, &ptr->flags) ||
+	    !tomoyo_io_printf(head, "\n")) {
+		head->read_avail = pos;
+		return false;
+	}
+	return true;
+}
+
+/**
  * tomoyo_print_entry - Print an ACL entry.
  *
  * @head: Pointer to "struct tomoyo_io_buffer".
@@ -1755,6 +1785,11 @@ static bool tomoyo_print_entry(struct tomoyo_io_buffer *head,
 				       head);
 		return tomoyo_print_path_number3_acl(head, acl);
 	}
+	if (acl_type == TOMOYO_TYPE_MOUNT_ACL) {
+		struct tomoyo_mount_acl *acl
+			= container_of(ptr, struct tomoyo_mount_acl, head);
+		return tomoyo_print_mount_acl(head, acl);
+	}
 	BUG(); /* This must not happen. */
 	return false;
 }
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index 565a1c11da53..3d819b139165 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -53,6 +53,7 @@ enum tomoyo_mode_index {
 
 /* Keywords for ACLs. */
 #define TOMOYO_KEYWORD_ALIAS                     "alias "
+#define TOMOYO_KEYWORD_ALLOW_MOUNT               "allow_mount "
 #define TOMOYO_KEYWORD_ALLOW_READ                "allow_read "
 #define TOMOYO_KEYWORD_DELETE                    "delete "
 #define TOMOYO_KEYWORD_DENY_REWRITE              "deny_rewrite "
@@ -90,6 +91,7 @@ enum tomoyo_acl_entry_type_index {
 	TOMOYO_TYPE_PATH2_ACL,
 	TOMOYO_TYPE_PATH_NUMBER_ACL,
 	TOMOYO_TYPE_PATH_NUMBER3_ACL,
+	TOMOYO_TYPE_MOUNT_ACL,
 };
 
 /* Index numbers for File Controls. */
@@ -116,7 +118,6 @@ enum tomoyo_path_acl_index {
 	TOMOYO_TYPE_SYMLINK,
 	TOMOYO_TYPE_REWRITE,
 	TOMOYO_TYPE_CHROOT,
-	TOMOYO_TYPE_MOUNT,
 	TOMOYO_TYPE_UMOUNT,
 	TOMOYO_MAX_PATH_OPERATION
 };
@@ -360,8 +361,8 @@ struct tomoyo_domain_info {
  *
  * Directives held by this structure are "allow_read/write", "allow_execute",
  * "allow_read", "allow_write", "allow_unlink", "allow_rmdir",
- * "allow_truncate", "allow_symlink", "allow_rewrite", "allow_chroot",
- * "allow_mount" and "allow_unmount".
+ * "allow_truncate", "allow_symlink", "allow_rewrite", "allow_chroot" and
+ * "allow_unmount".
  */
 struct tomoyo_path_acl {
 	struct tomoyo_acl_info head; /* type = TOMOYO_TYPE_PATH_ACL */
@@ -435,6 +436,29 @@ struct tomoyo_path2_acl {
 };
 
 /*
+ * tomoyo_mount_acl is a structure which is used for holding an
+ * entry for mount operation.
+ * It has following fields.
+ *
+ *  (1) "head" which is a "struct tomoyo_acl_info".
+ *  (2) "is_deleted" is boolean.
+ *  (3) "dev_name" is the device name.
+ *  (4) "dir_name" is the mount point.
+ *  (5) "flags" is the mount flags.
+ *
+ * Directives held by this structure are "allow_rename", "allow_link" and
+ * "allow_pivot_root".
+ */
+struct tomoyo_mount_acl {
+	struct tomoyo_acl_info head; /* type = TOMOYO_TYPE_MOUNT_ACL */
+	bool is_deleted;
+	struct tomoyo_name_union dev_name;
+	struct tomoyo_name_union dir_name;
+	struct tomoyo_name_union fs_type;
+	struct tomoyo_number_union flags;
+};
+
+/*
  * tomoyo_io_buffer is a structure which is used for reading and modifying
  * configuration via /sys/kernel/security/tomoyo/ interface.
  * It has many fields. ->read_var1 , ->read_var2 , ->write_var1 are used as
@@ -638,6 +662,9 @@ struct tomoyo_policy_manager_entry {
 /* Check whether the given name matches the given name_union. */
 bool tomoyo_compare_name_union(const struct tomoyo_path_info *name,
 			       const struct tomoyo_name_union *ptr);
+/* Check whether the given number matches the given number_union. */
+bool tomoyo_compare_number_union(const unsigned long value,
+				 const struct tomoyo_number_union *ptr);
 /* Check whether the domain has too many ACL entries to hold. */
 bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r);
 /* Transactional sprintf() for policy dump. */
@@ -699,6 +726,12 @@ const char *tomoyo_path_number32keyword(const u8 operation);
 const char *tomoyo_get_last_name(const struct tomoyo_domain_info *domain);
 /* Convert single path operation to operation name. */
 const char *tomoyo_path2keyword(const u8 operation);
+/* Fill "struct tomoyo_request_info". */
+int tomoyo_init_request_info(struct tomoyo_request_info *r,
+			     struct tomoyo_domain_info *domain);
+/* Check permission for mount operation. */
+int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
+			    unsigned long flags, void *data_page);
 /* Create "alias" entry in exception policy. */
 int tomoyo_write_alias_policy(char *data, const bool is_delete);
 /*
@@ -721,6 +754,9 @@ int tomoyo_write_file_policy(char *data, struct tomoyo_domain_info *domain,
 			     const bool is_delete);
 /* Create "allow_read" entry in exception policy. */
 int tomoyo_write_globally_readable_policy(char *data, const bool is_delete);
+/* Create "allow_mount" entry in domain policy. */
+int tomoyo_write_mount_policy(char *data, struct tomoyo_domain_info *domain,
+			      const bool is_delete);
 /* Create "deny_rewrite" entry in exception policy. */
 int tomoyo_write_no_rewrite_policy(char *data, const bool is_delete);
 /* Create "file_pattern" entry in exception policy. */
@@ -735,7 +771,9 @@ struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname);
 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 							    domainname,
 							    const u8 profile);
-
+/* Get patterned pathname. */
+const struct tomoyo_path_info *
+tomoyo_get_file_pattern(const struct tomoyo_path_info *filename);
 /* Allocate memory for "struct tomoyo_path_group". */
 struct tomoyo_path_group *tomoyo_get_path_group(const char *group_name);
 struct tomoyo_number_group *tomoyo_get_number_group(const char *group_name);
@@ -972,6 +1010,16 @@ static inline bool tomoyo_is_same_path_number_acl
 		&& tomoyo_is_same_number_union(&p1->number, &p2->number);
 }
 
+static inline bool tomoyo_is_same_mount_acl(const struct tomoyo_mount_acl *p1,
+					    const struct tomoyo_mount_acl *p2)
+{
+	return tomoyo_is_same_acl_head(&p1->head, &p2->head) &&
+		tomoyo_is_same_name_union(&p1->dev_name, &p2->dev_name) &&
+		tomoyo_is_same_name_union(&p1->dir_name, &p2->dir_name) &&
+		tomoyo_is_same_name_union(&p1->fs_type, &p2->fs_type) &&
+		tomoyo_is_same_number_union(&p1->flags, &p2->flags);
+}
+
 static inline bool tomoyo_is_same_domain_initializer_entry
 (const struct tomoyo_domain_initializer_entry *p1,
  const struct tomoyo_domain_initializer_entry *p2)
diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 727cc723f87d..ae32cab8ec7e 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -24,7 +24,6 @@ static const char *tomoyo_path_keyword[TOMOYO_MAX_PATH_OPERATION] = {
 	[TOMOYO_TYPE_SYMLINK]    = "symlink",
 	[TOMOYO_TYPE_REWRITE]    = "rewrite",
 	[TOMOYO_TYPE_CHROOT]     = "chroot",
-	[TOMOYO_TYPE_MOUNT]      = "mount",
 	[TOMOYO_TYPE_UMOUNT]     = "unmount",
 };
 
@@ -108,8 +107,8 @@ bool tomoyo_compare_number_union(const unsigned long value,
  *
  * Returns mode.
  */
-static int tomoyo_init_request_info(struct tomoyo_request_info *r,
-				    struct tomoyo_domain_info *domain)
+int tomoyo_init_request_info(struct tomoyo_request_info *r,
+			     struct tomoyo_domain_info *domain)
 {
 	memset(r, 0, sizeof(*r));
 	if (!domain)
@@ -487,7 +486,7 @@ static int tomoyo_update_file_pattern_entry(const char *pattern,
  *
  * Caller holds tomoyo_read_lock().
  */
-static const struct tomoyo_path_info *
+const struct tomoyo_path_info *
 tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
 {
 	struct tomoyo_pattern_entry *ptr;
@@ -1418,7 +1417,7 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
 }
 
 /**
- * tomoyo_path_perm - Check permission for "unlink", "rmdir", "truncate", "symlink", "rewrite", "chroot", "mount" and "unmount".
+ * tomoyo_path_perm - Check permission for "unlink", "rmdir", "truncate", "symlink", "rewrite", "chroot" and "unmount".
  *
  * @operation: Type of operation.
  * @path:      Pointer to "struct path".
diff --git a/security/tomoyo/gc.c b/security/tomoyo/gc.c
index 78100180d23d..be2d3b935533 100644
--- a/security/tomoyo/gc.c
+++ b/security/tomoyo/gc.c
@@ -124,6 +124,16 @@ static void tomoyo_del_acl(struct tomoyo_acl_info *acl)
 			tomoyo_put_number_union(&entry->minor);
 		}
 		break;
+	case TOMOYO_TYPE_MOUNT_ACL:
+		{
+			struct tomoyo_mount_acl *entry
+				= container_of(acl, typeof(*entry), head);
+			tomoyo_put_name_union(&entry->dev_name);
+			tomoyo_put_name_union(&entry->dir_name);
+			tomoyo_put_name_union(&entry->fs_type);
+			tomoyo_put_number_union(&entry->flags);
+		}
+		break;
 	default:
 		printk(KERN_WARNING "Unknown type\n");
 		break;
diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c
new file mode 100644
index 000000000000..507be09e93a9
--- /dev/null
+++ b/security/tomoyo/mount.c
@@ -0,0 +1,366 @@
+/*
+ * security/tomoyo/mount.c
+ *
+ * Copyright (C) 2005-2010  NTT DATA CORPORATION
+ */
+
+#include <linux/slab.h>
+#include "common.h"
+
+/* Keywords for mount restrictions. */
+
+/* Allow to call 'mount --bind /source_dir /dest_dir' */
+#define TOMOYO_MOUNT_BIND_KEYWORD                        "--bind"
+/* Allow to call 'mount --move /old_dir    /new_dir ' */
+#define TOMOYO_MOUNT_MOVE_KEYWORD                        "--move"
+/* Allow to call 'mount -o remount /dir             ' */
+#define TOMOYO_MOUNT_REMOUNT_KEYWORD                     "--remount"
+/* Allow to call 'mount --make-unbindable /dir'       */
+#define TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD             "--make-unbindable"
+/* Allow to call 'mount --make-private /dir'          */
+#define TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD                "--make-private"
+/* Allow to call 'mount --make-slave /dir'            */
+#define TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD                  "--make-slave"
+/* Allow to call 'mount --make-shared /dir'           */
+#define TOMOYO_MOUNT_MAKE_SHARED_KEYWORD                 "--make-shared"
+
+/**
+ * tomoyo_encode2: Encode binary string to ascii string.
+ *
+ * @str: String in binary format.
+ *
+ * Returns pointer to @str in ascii format on success, NULL otherwise.
+ *
+ * This function uses kzalloc(), so caller must kfree() if this function
+ * didn't return NULL.
+ */
+static char *tomoyo_encode2(const char *str)
+{
+	int len = 0;
+	const char *p = str;
+	char *cp;
+	char *cp0;
+	if (!p)
+		return NULL;
+	while (*p) {
+		const unsigned char c = *p++;
+		if (c == '\\')
+			len += 2;
+		else if (c > ' ' && c < 127)
+			len++;
+		else
+			len += 4;
+	}
+	len++;
+	/* Reserve space for appending "/". */
+	cp = kzalloc(len + 10, GFP_NOFS);
+	if (!cp)
+		return NULL;
+	cp0 = cp;
+	p = str;
+	while (*p) {
+		const unsigned char c = *p++;
+		if (c == '\\') {
+			*cp++ = '\\';
+			*cp++ = '\\';
+		} else if (c > ' ' && c < 127) {
+			*cp++ = c;
+		} else {
+			*cp++ = '\\';
+			*cp++ = (c >> 6) + '0';
+			*cp++ = ((c >> 3) & 7) + '0';
+			*cp++ = (c & 7) + '0';
+		}
+	}
+	return cp0;
+}
+
+/**
+ * tomoyo_mount_acl2 - Check permission for mount() operation.
+ *
+ * @r:        Pointer to "struct tomoyo_request_info".
+ * @dev_name: Name of device file.
+ * @dir:      Pointer to "struct path".
+ * @type:     Name of filesystem type.
+ * @flags:    Mount options.
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+static int tomoyo_mount_acl2(struct tomoyo_request_info *r, char *dev_name,
+			     struct path *dir, char *type, unsigned long flags)
+{
+	struct path path;
+	struct tomoyo_acl_info *ptr;
+	struct file_system_type *fstype = NULL;
+	const char *requested_type = NULL;
+	const char *requested_dir_name = NULL;
+	const char *requested_dev_name = NULL;
+	struct tomoyo_path_info rtype;
+	struct tomoyo_path_info rdev;
+	struct tomoyo_path_info rdir;
+	int need_dev = 0;
+	int error = -ENOMEM;
+
+	/* Get fstype. */
+	requested_type = tomoyo_encode2(type);
+	if (!requested_type)
+		goto out;
+	rtype.name = requested_type;
+	tomoyo_fill_path_info(&rtype);
+
+	/* Get mount point. */
+	requested_dir_name = tomoyo_realpath_from_path(dir);
+	if (!requested_dir_name) {
+		error = -ENOMEM;
+		goto out;
+	}
+	rdir.name = requested_dir_name;
+	tomoyo_fill_path_info(&rdir);
+
+	/* Compare fs name. */
+	if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD)) {
+		/* dev_name is ignored. */
+	} else if (!strcmp(type, TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD) ||
+		   !strcmp(type, TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD) ||
+		   !strcmp(type, TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD) ||
+		   !strcmp(type, TOMOYO_MOUNT_MAKE_SHARED_KEYWORD)) {
+		/* dev_name is ignored. */
+	} else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD) ||
+		   !strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD)) {
+		need_dev = -1; /* dev_name is a directory */
+	} else {
+		fstype = get_fs_type(type);
+		if (!fstype) {
+			error = -ENODEV;
+			goto out;
+		}
+		if (fstype->fs_flags & FS_REQUIRES_DEV)
+			/* dev_name is a block device file. */
+			need_dev = 1;
+	}
+	if (need_dev) {
+		/* Get mount point or device file. */
+		if (kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
+			error = -ENOENT;
+			goto out;
+		}
+		requested_dev_name = tomoyo_realpath_from_path(&path);
+		if (!requested_dev_name) {
+			error = -ENOENT;
+			goto out;
+		}
+	} else {
+		/* Map dev_name to "<NULL>" if no dev_name given. */
+		if (!dev_name)
+			dev_name = "<NULL>";
+		requested_dev_name = tomoyo_encode2(dev_name);
+		if (!requested_dev_name) {
+			error = -ENOMEM;
+			goto out;
+		}
+	}
+	rdev.name = requested_dev_name;
+	tomoyo_fill_path_info(&rdev);
+	list_for_each_entry_rcu(ptr, &r->domain->acl_info_list, list) {
+		struct tomoyo_mount_acl *acl;
+		if (ptr->type != TOMOYO_TYPE_MOUNT_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_mount_acl, head);
+		if (acl->is_deleted ||
+		    !tomoyo_compare_number_union(flags, &acl->flags) ||
+		    !tomoyo_compare_name_union(&rtype, &acl->fs_type) ||
+		    !tomoyo_compare_name_union(&rdir, &acl->dir_name) ||
+		    (need_dev &&
+		     !tomoyo_compare_name_union(&rdev, &acl->dev_name)))
+			continue;
+		error = 0;
+		break;
+	}
+	if (error) {
+		const char *dev = tomoyo_get_file_pattern(&rdev)->name;
+		const char *dir = tomoyo_get_file_pattern(&rdir)->name;
+		int len = strlen(dev) + strlen(dir) + strlen(requested_type)
+			+ 64;
+		char *buf = kzalloc(len, GFP_NOFS);
+		if (buf) {
+			snprintf(buf, len - 1, "%s %s %s 0x%lX",
+				 dev, dir, requested_type, flags);
+			tomoyo_write_mount_policy(buf, r->domain, false);
+			kfree(buf);
+		}
+	}
+ out:
+	kfree(requested_dev_name);
+	kfree(requested_dir_name);
+	if (fstype)
+		put_filesystem(fstype);
+	kfree(requested_type);
+	return error;
+}
+
+/**
+ * tomoyo_mount_acl - Check permission for mount() operation.
+ *
+ * @r:        Pointer to "struct tomoyo_request_info".
+ * @dev_name: Name of device file.
+ * @dir:      Pointer to "struct path".
+ * @type:     Name of filesystem type.
+ * @flags:    Mount options.
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
+			    struct path *dir, char *type, unsigned long flags)
+{
+	int error;
+	error = -EPERM;
+	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
+		flags &= ~MS_MGC_MSK;
+	switch (flags & (MS_REMOUNT | MS_MOVE | MS_BIND)) {
+	case MS_REMOUNT:
+	case MS_MOVE:
+	case MS_BIND:
+	case 0:
+		break;
+	default:
+		printk(KERN_WARNING "ERROR: "
+		       "%s%s%sare given for single mount operation.\n",
+		       flags & MS_REMOUNT ? "'remount' " : "",
+		       flags & MS_MOVE    ? "'move' " : "",
+		       flags & MS_BIND    ? "'bind' " : "");
+		return -EINVAL;
+	}
+	switch (flags & (MS_UNBINDABLE | MS_PRIVATE | MS_SLAVE | MS_SHARED)) {
+	case MS_UNBINDABLE:
+	case MS_PRIVATE:
+	case MS_SLAVE:
+	case MS_SHARED:
+	case 0:
+		break;
+	default:
+		printk(KERN_WARNING "ERROR: "
+		       "%s%s%s%sare given for single mount operation.\n",
+		       flags & MS_UNBINDABLE ? "'unbindable' " : "",
+		       flags & MS_PRIVATE    ? "'private' " : "",
+		       flags & MS_SLAVE      ? "'slave' " : "",
+		       flags & MS_SHARED     ? "'shared' " : "");
+		return -EINVAL;
+	}
+	if (flags & MS_REMOUNT)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_REMOUNT_KEYWORD,
+				      flags & ~MS_REMOUNT);
+	else if (flags & MS_MOVE)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_MOVE_KEYWORD,
+				      flags & ~MS_MOVE);
+	else if (flags & MS_BIND)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_BIND_KEYWORD,
+				      flags & ~MS_BIND);
+	else if (flags & MS_UNBINDABLE)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD,
+				      flags & ~MS_UNBINDABLE);
+	else if (flags & MS_PRIVATE)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD,
+				      flags & ~MS_PRIVATE);
+	else if (flags & MS_SLAVE)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD,
+				      flags & ~MS_SLAVE);
+	else if (flags & MS_SHARED)
+		error = tomoyo_mount_acl(r, dev_name, dir,
+				      TOMOYO_MOUNT_MAKE_SHARED_KEYWORD,
+				      flags & ~MS_SHARED);
+	else
+		error = tomoyo_mount_acl2(r, dev_name, dir, type, flags);
+	if (r->mode != TOMOYO_CONFIG_ENFORCING)
+		error = 0;
+	return error;
+}
+
+/**
+ * tomoyo_mount_permission - Check permission for mount() operation.
+ *
+ * @dev_name:  Name of device file.
+ * @path:      Pointer to "struct path".
+ * @type:      Name of filesystem type. May be NULL.
+ * @flags:     Mount options.
+ * @data_page: Optional data. May be NULL.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
+			    unsigned long flags, void *data_page)
+{
+	struct tomoyo_request_info r;
+	int error;
+	int idx;
+
+	if (tomoyo_init_request_info(&r, NULL) == TOMOYO_CONFIG_DISABLED)
+		return 0;
+	if (!type)
+		type = "<NULL>";
+	idx = tomoyo_read_lock();
+	error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
+	tomoyo_read_unlock(idx);
+	return error;
+}
+
+/**
+ * tomoyo_write_mount_policy - Write "struct tomoyo_mount_acl" list.
+ *
+ * @data:      String to parse.
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_write_mount_policy(char *data, struct tomoyo_domain_info *domain,
+			      const bool is_delete)
+{
+	struct tomoyo_acl_info *ptr;
+	struct tomoyo_mount_acl e = { .head.type = TOMOYO_TYPE_MOUNT_ACL };
+	int error = is_delete ? -ENOENT : -ENOMEM;
+	char *w[4];
+	if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[3][0])
+		return -EINVAL;
+	if (!tomoyo_parse_name_union(w[0], &e.dev_name) ||
+	    !tomoyo_parse_name_union(w[1], &e.dir_name) ||
+	    !tomoyo_parse_name_union(w[2], &e.fs_type) ||
+	    !tomoyo_parse_number_union(w[3], &e.flags))
+		goto out;
+	if (mutex_lock_interruptible(&tomoyo_policy_lock))
+		goto out;
+	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
+		struct tomoyo_mount_acl *acl =
+			container_of(ptr, struct tomoyo_mount_acl, head);
+		if (!tomoyo_is_same_mount_acl(acl, &e))
+			continue;
+		acl->is_deleted = is_delete;
+		error = 0;
+		break;
+	}
+	if (!is_delete && error) {
+		struct tomoyo_mount_acl *entry =
+			tomoyo_commit_ok(&e, sizeof(e));
+		if (entry) {
+			list_add_tail_rcu(&entry->head.list,
+					  &domain->acl_info_list);
+			error = 0;
+		}
+	}
+	mutex_unlock(&tomoyo_policy_lock);
+ out:
+	tomoyo_put_name_union(&e.dev_name);
+	tomoyo_put_name_union(&e.dir_name);
+	tomoyo_put_name_union(&e.fs_type);
+	tomoyo_put_number_union(&e.flags);
+	return error;
+}
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index bbe00429b3f5..5d64d409b112 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -226,7 +226,7 @@ static int tomoyo_path_chroot(struct path *path)
 static int tomoyo_sb_mount(char *dev_name, struct path *path,
 			   char *type, unsigned long flags, void *data)
 {
-	return tomoyo_path_perm(TOMOYO_TYPE_MOUNT, path);
+	return tomoyo_mount_permission(dev_name, path, type, flags, data);
 }
 
 static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)