ovl: fix race in private xattr checks

[uclinux-h8/linux.git] / fs / overlayfs / inode.c

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index af2d18c..07d74b2 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -235,26 +235,36 @@ out:
        return err;
 }
 
+static bool ovl_need_xattr_filter(struct dentry *dentry,
+                                 enum ovl_path_type type)
+{
+       return type == OVL_PATH_UPPER && S_ISDIR(dentry->d_inode->i_mode);
+}
+
 ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
                     void *value, size_t size)
 {
-       if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
-           ovl_is_private_xattr(name))
+       struct path realpath;
+       enum ovl_path_type type = ovl_path_real(dentry, &realpath);
+
+       if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
                return -ENODATA;
 
-       return vfs_getxattr(ovl_dentry_real(dentry), name, value, size);
+       return vfs_getxattr(realpath.dentry, name, value, size);
 }
 
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 {
+       struct path realpath;
+       enum ovl_path_type type = ovl_path_real(dentry, &realpath);
        ssize_t res;
        int off;
 
-       res = vfs_listxattr(ovl_dentry_real(dentry), list, size);
+       res = vfs_listxattr(realpath.dentry, list, size);
        if (res <= 0 || size == 0)
                return res;
 
-       if (ovl_path_type(dentry->d_parent) != OVL_PATH_MERGE)
+       if (!ovl_need_xattr_filter(dentry, type))
                return res;
 
        /* filter out private xattrs */
@@ -279,17 +289,16 @@ int ovl_removexattr(struct dentry *dentry, const char *name)
 {
        int err;
        struct path realpath;
-       enum ovl_path_type type;
+       enum ovl_path_type type = ovl_path_real(dentry, &realpath);
 
        err = ovl_want_write(dentry);
        if (err)
                goto out;
 
-       if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
-           ovl_is_private_xattr(name))
+       err = -ENODATA;
+       if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
                goto out_drop_write;
 
-       type = ovl_path_real(dentry, &realpath);
        if (type == OVL_PATH_LOWER) {
                err = vfs_getxattr(realpath.dentry, name, NULL, 0);
                if (err < 0)