From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 465B9C432BE for ; Thu, 26 Aug 2021 06:39:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EE39610CB for ; Thu, 26 Aug 2021 06:39:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239112AbhHZGkl (ORCPT ); Thu, 26 Aug 2021 02:40:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:38172 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234415AbhHZGkk (ORCPT ); Thu, 26 Aug 2021 02:40:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6D3BE610CA; Thu, 26 Aug 2021 06:39:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1629959994; bh=YDdDJ8UVx6APE79kWD1KiYfDKlzcYXXRqdvvgHhmVzk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aP1s1YHNUe+n+sZuGly73Kfys6U2PxpfwFwgeAYLORkHO7O6dD9MtMQfP356DdWGl wrpN8612/+wvBVbxWHBr0wqM9pSv8bl9T4/vi+eECS1MbOCg9OAz+0F+EQNUsPQoX5 4tg4ywEmo8UqB0x1lnyowZ9+UsBPOWsukJYtg3Cg= Date: Thu, 26 Aug 2021 08:39:44 +0200 From: Greg KH To: Peter Collingbourne Cc: "David S. Miller" , Jakub Kicinski , Colin Ian King , Cong Wang , Al Viro , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] net: don't unconditionally copy_from_user a struct ifreq for socket ioctls Message-ID: References: <20210826012722.3210359-1-pcc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210826012722.3210359-1-pcc@google.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Aug 25, 2021 at 06:27:22PM -0700, Peter Collingbourne wrote: > A common implementation of isatty(3) involves calling a ioctl passing > a dummy struct argument and checking whether the syscall failed -- > bionic and glibc use TCGETS (passing a struct termios), and musl uses > TIOCGWINSZ (passing a struct winsize). If the FD is a socket, we will > copy sizeof(struct ifreq) bytes of data from the argument and return > -EFAULT if that fails. The result is that the isatty implementations > may return a non-POSIX-compliant value in errno in the case where part > of the dummy struct argument is inaccessible, as both struct termios > and struct winsize are smaller than struct ifreq (at least on arm64). > > Although there is usually enough stack space following the argument > on the stack that this did not present a practical problem up to now, > with MTE stack instrumentation it's more likely for the copy to fail, > as the memory following the struct may have a different tag. > > Fix the problem by adding an early check for whether the ioctl is a > valid socket ioctl, and return -ENOTTY if it isn't. > > Fixes: 44c02a2c3dc5 ("dev_ioctl(): move copyin/copyout to callers") > Link: https://linux-review.googlesource.com/id/I869da6cf6daabc3e4b7b82ac979683ba05e27d4d > Signed-off-by: Peter Collingbourne > Cc: # 4.19 > --- > include/linux/netdevice.h | 1 + > net/core/dev_ioctl.c | 64 ++++++++++++++++++++++++++++++++------- > net/socket.c | 6 +++- > 3 files changed, 59 insertions(+), 12 deletions(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index eaf5bb008aa9..481b90ef0d32 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -4012,6 +4012,7 @@ int netdev_rx_handler_register(struct net_device *dev, > void netdev_rx_handler_unregister(struct net_device *dev); > > bool dev_valid_name(const char *name); > +bool is_dev_ioctl_cmd(unsigned int cmd); "is_socket_ioctl_cmd()" might be a better global name here. thanks, greg k-h