staging: lustre: llite: Setting xattr are properly checked with and without ACLs

Setting extended attributes permissions are properly checked with and
without ACLs. In user.* namespace, only regular files and directories
can have extended attributes. For sticky directories, only the owner
and privileged user can write attributes.
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-1482
Reviewed-on: http://review.whamcloud.com/21496Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/xattr.c

@@ -132,6 +132,15 @@ ll_xattr_set_common(const struct xattr_handler *handler,
 	    (!strcmp(name, "ima") || !strcmp(name, "evm")))
 		return -EOPNOTSUPP;
 
+	/*
+	 * In user.* namespace, only regular files and directories can have
+	 * extended attributes.
+	 */
+	if (handler->flags == XATTR_USER_T) {
+		if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
+			return -EPERM;
+	}
+
 	sprintf(fullname, "%s%s\n", handler->prefix, name);
 	rc = md_setxattr(sbi->ll_md_exp, ll_inode2fid(inode),
 			 valid, fullname, pv, size, 0, flags,