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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29045C05027 for ; Thu, 2 Feb 2023 08:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231691AbjBBIRm (ORCPT ); Thu, 2 Feb 2023 03:17:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229761AbjBBIRk (ORCPT ); Thu, 2 Feb 2023 03:17:40 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90CBB84B6D for ; Thu, 2 Feb 2023 00:16:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675325799; 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=olwkKMi58scfsYQUIBGFK2Y7akvONH6lMg+1wDEkFRQ=; b=O1S0Yy56P2PNTerLLb0SJKhtYUclRohWDfZtr9/AoQaxDZCP5zusSlnp1OSKNX8pQGWsb+ zoAYttctRkSXuqnPzQb0LsnQF16nDpf7/42tsxFTwxWryfs5BAKDSAFjpbVn1yfxHf5ZOU KXOGMWXVs40U0yAhBBDPCM5xP4Wh45Q= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-645-BcYoTWsmOmeymVp6wF8weg-1; Thu, 02 Feb 2023 03:16:38 -0500 X-MC-Unique: BcYoTWsmOmeymVp6wF8weg-1 Received: by mail-ej1-f69.google.com with SMTP id ae2-20020a17090725c200b0088d91fe7ec5so1032988ejc.1 for ; Thu, 02 Feb 2023 00:16:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=olwkKMi58scfsYQUIBGFK2Y7akvONH6lMg+1wDEkFRQ=; b=cSzoPUo30bSDw35X6BrTtx95VKba+zjNHhzXs7alZb2Re4qYQd6rpKa8PqOZvlQF5p 7srnvC2NDDTuMZI/udPa9uGSBFQFlxUfCEpZAGJy3kQBsL++M3k14REWvkGXBk/HOx7K XncyN3MPQYG6aBau1uk8UPLArjGqTECJo3JdbmLK9YeeGhz6mjciWknj4yOHcQYbqD3W YGqQuZLGjeakXHXtFhCP1vyeVi6AUhWVYzIm/d0m6xdM/u5iJDoBmWc4ZfSMOnT63+hW 58jwaazCnSlh1obtCwnyt/TMGHKvAsYxv9uUJtacfCZFb1MRXmGR6J80w7DxZhkQZRdz Xu6A== X-Gm-Message-State: AO0yUKXW3aQ09sw+22YjeOF00GEHsZZS51zKSe/Ma6zKS4wv0jH8b3d+ bfRWCywO860UhsLBG1Ho2/n0SQ1b3KJoGbp5I5Y1S/Ubi6lBsdyHXkVP4e+si3kUUwZ4M6U5yiy mbd+OEC9ntZkY+ifl X-Received: by 2002:a50:9e49:0:b0:4a2:5f29:d862 with SMTP id z67-20020a509e49000000b004a25f29d862mr5232049ede.23.1675325796459; Thu, 02 Feb 2023 00:16:36 -0800 (PST) X-Google-Smtp-Source: AK7set9M3wng4VZ6hN2rjvOcTVHcFIZcL5nLSL+jWCSigokzXdW2Yes5ohNG43w504eVt9X/VHUulw== X-Received: by 2002:a50:9e49:0:b0:4a2:5f29:d862 with SMTP id z67-20020a509e49000000b004a25f29d862mr5232033ede.23.1675325796290; Thu, 02 Feb 2023 00:16:36 -0800 (PST) Received: from redhat.com ([2.52.156.122]) by smtp.gmail.com with ESMTPSA id a6-20020aa7cf06000000b004a23558f01fsm6845963edy.43.2023.02.02.00.16.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Feb 2023 00:16:35 -0800 (PST) Date: Thu, 2 Feb 2023 03:16:30 -0500 From: "Michael S. Tsirkin" To: Heng Qi Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Jason Wang , Paolo Abeni , Jakub Kicinski , John Fastabend , "David S . Miller" , Daniel Borkmann , Alexei Starovoitov , Eric Dumazet , Xuan Zhuo Subject: Re: [PATCH net-next v2] virtio-net: fix possible unsigned integer overflow Message-ID: <20230202031609-mutt-send-email-mst@kernel.org> References: <20230131085004.98687-1-hengqi@linux.alibaba.com> <20230202030550-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Feb 02, 2023 at 04:14:51PM +0800, Heng Qi wrote: > > > 在 2023/2/2 下午4:07, Michael S. Tsirkin 写道: > > On Tue, Jan 31, 2023 at 04:50:04PM +0800, Heng Qi wrote: > > > When the single-buffer xdp is loaded and after xdp_linearize_page() > > > is called, *num_buf becomes 0 and (*num_buf - 1) may overflow into > > > a large integer in virtnet_build_xdp_buff_mrg(), resulting in > > > unexpected packet dropping. > > > > > > Fixes: ef75cb51f139 ("virtio-net: build xdp_buff with multi buffers") > > > Signed-off-by: Heng Qi > > > Reviewed-by: Xuan Zhuo > > > Signed-off-by: Michael S. Tsirkin > > > --- > > > v1->v2: > > > - Change the type of num_buf from unsigned int to int. @Michael S . Tsirkin > > > - Some cleaner codes. @Michael S . Tsirkin > > > > > > drivers/net/virtio_net.c | 15 +++++++++------ > > > 1 file changed, 9 insertions(+), 6 deletions(-) > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > index aaa6fe9b214a..8102861785a2 100644 > > > --- a/drivers/net/virtio_net.c > > > +++ b/drivers/net/virtio_net.c > > > @@ -716,7 +716,7 @@ static unsigned int virtnet_get_headroom(struct virtnet_info *vi) > > > * have enough headroom. > > > */ > > > static struct page *xdp_linearize_page(struct receive_queue *rq, > > > - u16 *num_buf, > > > + int *num_buf, > > > struct page *p, > > > int offset, > > > int page_off, > > > @@ -816,7 +816,7 @@ static struct sk_buff *receive_small(struct net_device *dev, > > > if (unlikely(xdp_headroom < virtnet_get_headroom(vi))) { > > > int offset = buf - page_address(page) + header_offset; > > > unsigned int tlen = len + vi->hdr_len; > > > - u16 num_buf = 1; > > > + int num_buf = 1; > > > xdp_headroom = virtnet_get_headroom(vi); > > > header_offset = VIRTNET_RX_PAD + xdp_headroom; > > > @@ -989,7 +989,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev, > > > void *buf, > > > unsigned int len, > > > unsigned int frame_sz, > > > - u16 *num_buf, > > > + int *num_buf, > > > unsigned int *xdp_frags_truesize, > > > struct virtnet_rq_stats *stats) > > > { > > > @@ -1007,6 +1007,9 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev, > > > xdp_prepare_buff(xdp, buf - VIRTIO_XDP_HEADROOM, > > > VIRTIO_XDP_HEADROOM + vi->hdr_len, len - vi->hdr_len, true); > > > + if (!*num_buf) > > > + return 0; > > > + > > > if (*num_buf > 1) { > > > /* If we want to build multi-buffer xdp, we need > > > * to specify that the flags of xdp_buff have the > > Ouch. Why is this here? Merged so pls remove by a follow up patch, the > > rest of the code handles 0 fine. I'm not sure this introduces a bug by > > we don't want spaghetti code. > > Yes it would work without this, but I was keeping this because I wanted it > to handle 0 early and exit early. > > Do you want to remove this? > > Thanks. why do you want to exit early? > > > > > @@ -1020,10 +1023,10 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev, > > > shinfo->xdp_frags_size = 0; > > > } > > > - if ((*num_buf - 1) > MAX_SKB_FRAGS) > > > + if (*num_buf > MAX_SKB_FRAGS + 1) > > > return -EINVAL; > > > - while ((--*num_buf) >= 1) { > > > + while (--*num_buf > 0) { > > > buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx); > > > if (unlikely(!buf)) { > > > pr_debug("%s: rx error: %d buffers out of %d missing\n", > > > @@ -1076,7 +1079,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > > > struct virtnet_rq_stats *stats) > > > { > > > struct virtio_net_hdr_mrg_rxbuf *hdr = buf; > > > - u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers); > > > + int num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers); > > > struct page *page = virt_to_head_page(buf); > > > int offset = buf - page_address(page); > > > struct sk_buff *head_skb, *curr_skb; > > > -- > > > 2.19.1.6.gb485710b