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=-17.3 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,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 392EFC433B4 for ; Fri, 23 Apr 2021 04:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE06C6128A for ; Fri, 23 Apr 2021 04:33:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229643AbhDWEeA (ORCPT ); Fri, 23 Apr 2021 00:34:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:29579 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229454AbhDWEd6 (ORCPT ); Fri, 23 Apr 2021 00:33:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619152402; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=S/rpXgbgmc50aCP+Bf5P8vd/NdVHXa2pUILMXzqjzjQ=; b=aiL4a84hj2j+oCKxcG9EUIh/1sfkPn/iqnrWL096iuaCcUNUkSMt1wHJEdopVGAa9H8CWe dDYS//2ylAAtZWuUxtlzm55CGWMsFzEue4UDydqp53EWaZ7EZgj7dixdN1NKHpUtH61ecL ZCdB2B+MhDSVkAl3Vu945n4oNZZrPSA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-534-DaCL4IoKPQ2-RlU-wMUd2A-1; Fri, 23 Apr 2021 00:33:19 -0400 X-MC-Unique: DaCL4IoKPQ2-RlU-wMUd2A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 479EC18B9F84; Fri, 23 Apr 2021 04:33:18 +0000 (UTC) Received: from wangxiaodeMacBook-Air.local (ovpn-13-225.pek2.redhat.com [10.72.13.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id C96DD19442; Fri, 23 Apr 2021 04:33:10 +0000 (UTC) Subject: Re: [PATCH net-next] virtio-net: fix use-after-free in skb_gro_receive To: Xuan Zhuo Cc: "Michael S. Tsirkin" , "David S. Miller" , Jakub Kicinski , virtualization@lists.linux-foundation.org, Ido Schimmel , netdev@vger.kernel.org References: <1619151585.3098595-1-xuanzhuo@linux.alibaba.com> From: Jason Wang Message-ID: Date: Fri, 23 Apr 2021 12:33:09 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <1619151585.3098595-1-xuanzhuo@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 在 2021/4/23 下午12:19, Xuan Zhuo 写道: > On Fri, 23 Apr 2021 12:08:34 +0800, Jason Wang wrote: >> 在 2021/4/22 下午11:16, Xuan Zhuo 写道: >>> When "headroom" > 0, the actual allocated memory space is the entire >>> page, so the address of the page should be used when passing it to >>> build_skb(). >>> >>> BUG: KASAN: use-after-free in skb_gro_receive (net/core/skbuff.c:4260) >>> Write of size 16 at addr ffff88811619fffc by task kworker/u9:0/534 >>> CPU: 2 PID: 534 Comm: kworker/u9:0 Not tainted 5.12.0-rc7-custom-16372-gb150be05b806 #3382 >>> Hardware name: QEMU MSN2700, BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 >>> Workqueue: xprtiod xs_stream_data_receive_workfn [sunrpc] >>> Call Trace: >>> >>> dump_stack (lib/dump_stack.c:122) >>> print_address_description.constprop.0 (mm/kasan/report.c:233) >>> kasan_report.cold (mm/kasan/report.c:400 mm/kasan/report.c:416) >>> skb_gro_receive (net/core/skbuff.c:4260) >>> tcp_gro_receive (net/ipv4/tcp_offload.c:266 (discriminator 1)) >>> tcp4_gro_receive (net/ipv4/tcp_offload.c:316) >>> inet_gro_receive (net/ipv4/af_inet.c:1545 (discriminator 2)) >>> dev_gro_receive (net/core/dev.c:6075) >>> napi_gro_receive (net/core/dev.c:6168 net/core/dev.c:6198) >>> receive_buf (drivers/net/virtio_net.c:1151) virtio_net >>> virtnet_poll (drivers/net/virtio_net.c:1415 drivers/net/virtio_net.c:1519) virtio_net >>> __napi_poll (net/core/dev.c:6964) >>> net_rx_action (net/core/dev.c:7033 net/core/dev.c:7118) >>> __do_softirq (./arch/x86/include/asm/jump_label.h:25 ./include/linux/jump_label.h:200 ./include/trace/events/irq.h:142 kernel/softirq.c:346) >>> irq_exit_rcu (kernel/softirq.c:221 kernel/softirq.c:422 kernel/softirq.c:434) >>> common_interrupt (arch/x86/kernel/irq.c:240 (discriminator 14)) >>> >>> >>> Fixes: fb32856b16ad ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom") >>> Signed-off-by: Xuan Zhuo >>> Reported-by: Ido Schimmel >>> Tested-by: Ido Schimmel >>> --- >> >> Acked-by: Jason Wang >> >> The codes became hard to read, I think we can try to do some cleanups on >> top to make it easier to read. >> >> Thanks > Yes, this piece of code needs to be sorted out. Especially the big and mergeable > scenarios should be handled separately. Remove the mergeable code from this > function, and mergeable uses a new function alone. Right, another thing is that we may consider to relax the checking of len < GOOD_COPY_LEN. Our QE still see low PPS compared with the code before 3226b158e67c ("net: avoid 32 x truesize under-estimation for tiny skbs"). Thanks > > Thanks. > >> >>> drivers/net/virtio_net.c | 12 +++++++++--- >>> 1 file changed, 9 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >>> index 74d2d49264f3..7fda2ae4c40f 100644 >>> --- a/drivers/net/virtio_net.c >>> +++ b/drivers/net/virtio_net.c >>> @@ -387,7 +387,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, >>> unsigned int copy, hdr_len, hdr_padded_len; >>> struct page *page_to_free = NULL; >>> int tailroom, shinfo_size; >>> - char *p, *hdr_p; >>> + char *p, *hdr_p, *buf; >>> >>> p = page_address(page) + offset; >>> hdr_p = p; >>> @@ -403,11 +403,15 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, >>> * space are aligned. >>> */ >>> if (headroom) { >>> - /* The actual allocated space size is PAGE_SIZE. */ >>> + /* Buffers with headroom use PAGE_SIZE as alloc size, >>> + * see add_recvbuf_mergeable() + get_mergeable_buf_len() >>> + */ >>> truesize = PAGE_SIZE; >>> tailroom = truesize - len - offset; >>> + buf = page_address(page); >>> } else { >>> tailroom = truesize - len; >>> + buf = p; >>> } >>> >>> len -= hdr_len; >>> @@ -416,11 +420,13 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, >>> >>> shinfo_size = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); >>> >>> + /* copy small packet so we can reuse these pages */ >>> if (!NET_IP_ALIGN && len > GOOD_COPY_LEN && tailroom >= shinfo_size) { >>> - skb = build_skb(p, truesize); >>> + skb = build_skb(buf, truesize); >>> if (unlikely(!skb)) >>> return NULL; >>> >>> + skb_reserve(skb, p - buf); >>> skb_put(skb, len); >>> goto ok; >>> }