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,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 C0C3DC433E6 for ; Thu, 4 Feb 2021 00:29:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CDC464F6A for ; Thu, 4 Feb 2021 00:29:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233914AbhBDA3e (ORCPT ); Wed, 3 Feb 2021 19:29:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:35158 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233702AbhBDA32 (ORCPT ); Wed, 3 Feb 2021 19:29:28 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 280FA64DAF; Thu, 4 Feb 2021 00:28:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612398527; bh=zD2l0UjA1q+ASc/JvfPwKEcmrFFE1IsTq9HetqkNVTY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qvbtyNIB+U347rqUQYvn8lAveJpjU/PwnZj0Y4EoNnmHDNe717tfhtI5sAv3RgTpw iTK2hGxvC+LoVV68YKWeTvKHtSUv56EowEH9YWjrm6biIsx+ZrRal9oI6DYDyy50Tl /pe+BHe4pD3GGxNB4j+1v5/YNjPQ9p+UlXLUxgf7zE8njI5FD85IQtq4IpG+ShDqIH sNTcszrh3cEDDC+DmKv14rVTl6SvyUFkhIEar+kF5EHNxWbV3eDZsX5erTTbMY3/d5 5fkGRuANjZlE0mlw48FXcsvwa69n79xMTatsi29dznaEJqPDQXXNB599aR8FnlU+rD iuEIw050TksZQ== Date: Wed, 3 Feb 2021 16:28:46 -0800 From: Jakub Kicinski To: Sabyrzhan Tasbolatov Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+c2a7e5c5211605a90865@syzkaller.appspotmail.com Subject: Re: [PATCH] net/qrtr: restrict user-controlled length in qrtr_tun_write_iter() Message-ID: <20210203162846.56a90288@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210202092059.1361381-1-snovitoll@gmail.com> References: <20210202092059.1361381-1-snovitoll@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, 2 Feb 2021 15:20:59 +0600 Sabyrzhan Tasbolatov wrote: > syzbot found WARNING in qrtr_tun_write_iter [1] when write_iter length > exceeds KMALLOC_MAX_SIZE causing order >= MAX_ORDER condition. > > Additionally, there is no check for 0 length write. > > [1] > WARNING: mm/page_alloc.c:5011 > [..] > Call Trace: > alloc_pages_current+0x18c/0x2a0 mm/mempolicy.c:2267 > alloc_pages include/linux/gfp.h:547 [inline] > kmalloc_order+0x2e/0xb0 mm/slab_common.c:837 > kmalloc_order_trace+0x14/0x120 mm/slab_common.c:853 > kmalloc include/linux/slab.h:557 [inline] > kzalloc include/linux/slab.h:682 [inline] > qrtr_tun_write_iter+0x8a/0x180 net/qrtr/tun.c:83 > call_write_iter include/linux/fs.h:1901 [inline] > > Reported-by: syzbot+c2a7e5c5211605a90865@syzkaller.appspotmail.com > Signed-off-by: Sabyrzhan Tasbolatov > --- > net/qrtr/tun.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c > index 15ce9b642b25..b238c40a9984 100644 > --- a/net/qrtr/tun.c > +++ b/net/qrtr/tun.c > @@ -80,6 +80,12 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from) > ssize_t ret; > void *kbuf; > > + if (!len) > + return -EINVAL; > + > + if (len > KMALLOC_MAX_SIZE) > + return -ENOMEM; > + > kbuf = kzalloc(len, GFP_KERNEL); For potential, separate clean up - this is followed by copy_from_iter_full(len) kzalloc() can probably be replaced by kmalloc()? > if (!kbuf) > return -ENOMEM;