TOMOYO: Fix mount flags checking order.

[linux-flexiantxendom0.git] / security / tomoyo / mount.c

diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c
index 8ba28fd..fe00cdf 100644 (file)
--- a/security/tomoyo/mount.c
+++ b/security/tomoyo/mount.c
@@ -1,7 +1,7 @@
 /*
  * security/tomoyo/mount.c
  *
- * Copyright (C) 2005-2010  NTT DATA CORPORATION
+ * Copyright (C) 2005-2011  NTT DATA CORPORATION
  */
 
 #include <linux/slab.h>
@@ -62,7 +62,7 @@ static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
  * tomoyo_mount_acl - Check permission for mount() operation.
  *
  * @r:        Pointer to "struct tomoyo_request_info".
- * @dev_name: Name of device file.
+ * @dev_name: Name of device file. Maybe NULL.
  * @dir:      Pointer to "struct path".
  * @type:     Name of filesystem type.
  * @flags:    Mount options.
@@ -75,6 +75,7 @@ static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
                            struct path *dir, const char *type,
                            unsigned long flags)
 {
+       struct tomoyo_obj_info obj = { };
        struct path path;
        struct file_system_type *fstype = NULL;
        const char *requested_type = NULL;
@@ -85,6 +86,7 @@ static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
        struct tomoyo_path_info rdir;
        int need_dev = 0;
        int error = -ENOMEM;
+       r->obj = &obj;
 
        /* Get fstype. */
        requested_type = tomoyo_encode(type);
@@ -94,6 +96,7 @@ static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
        tomoyo_fill_path_info(&rtype);
 
        /* Get mount point. */
+       obj.path2 = *dir;
        requested_dir_name = tomoyo_realpath_from_path(dir);
        if (!requested_dir_name) {
                error = -ENOMEM;
@@ -125,12 +128,12 @@ static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
        }
        if (need_dev) {
                /* Get mount point or device file. */
-               if (kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
+               if (!dev_name || kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
                        error = -ENOENT;
                        goto out;
                }
+               obj.path1 = path;
                requested_dev_name = tomoyo_realpath_from_path(&path);
-               path_put(&path);
                if (!requested_dev_name) {
                        error = -ENOENT;
                        goto out;
@@ -163,17 +166,20 @@ static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
        if (fstype)
                put_filesystem(fstype);
        kfree(requested_type);
+       /* Drop refcount obtained by kern_path(). */
+       if (obj.path1.dentry)
+               path_put(&obj.path1);
        return error;
 }
 
 /**
  * tomoyo_mount_permission - Check permission for mount() operation.
  *
- * @dev_name:  Name of device file.
+ * @dev_name:  Name of device file. Maybe NULL.
  * @path:      Pointer to "struct path".
- * @type:      Name of filesystem type. May be NULL.
+ * @type:      Name of filesystem type. Maybe NULL.
  * @flags:     Mount options.
- * @data_page: Optional data. May be NULL.
+ * @data_page: Optional data. Maybe NULL.
  *
  * Returns 0 on success, negative value otherwise.
  */
@@ -193,30 +199,32 @@ int tomoyo_mount_permission(char *dev_name, struct path *path,
        if (flags & MS_REMOUNT) {
                type = tomoyo_mounts[TOMOYO_MOUNT_REMOUNT];
                flags &= ~MS_REMOUNT;
-       }
-       if (flags & MS_MOVE) {
-               type = tomoyo_mounts[TOMOYO_MOUNT_MOVE];
-               flags &= ~MS_MOVE;
-       }
-       if (flags & MS_BIND) {
+       } else if (flags & MS_BIND) {
                type = tomoyo_mounts[TOMOYO_MOUNT_BIND];
                flags &= ~MS_BIND;
-       }
-       if (flags & MS_UNBINDABLE) {
-               type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE];
-               flags &= ~MS_UNBINDABLE;
-       }
-       if (flags & MS_PRIVATE) {
+       } else if (flags & MS_SHARED) {
+               if (flags & (MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+                       return -EINVAL;
+               type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED];
+               flags &= ~MS_SHARED;
+       } else if (flags & MS_PRIVATE) {
+               if (flags & (MS_SHARED | MS_SLAVE | MS_UNBINDABLE))
+                       return -EINVAL;
                type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE];
                flags &= ~MS_PRIVATE;
-       }
-       if (flags & MS_SLAVE) {
+       } else if (flags & MS_SLAVE) {
+               if (flags & (MS_SHARED | MS_PRIVATE | MS_UNBINDABLE))
+                       return -EINVAL;
                type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE];
                flags &= ~MS_SLAVE;
-       }
-       if (flags & MS_SHARED) {
-               type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED];
-               flags &= ~MS_SHARED;
+       } else if (flags & MS_UNBINDABLE) {
+               if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE))
+                       return -EINVAL;
+               type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE];
+               flags &= ~MS_UNBINDABLE;
+       } else if (flags & MS_MOVE) {
+               type = tomoyo_mounts[TOMOYO_MOUNT_MOVE];
+               flags &= ~MS_MOVE;
        }
        if (!type)
                type = "<NULL>";