From patchwork Wed Sep 8 11:42:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 508259 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=-16.1 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 autolearn=unavailable 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 C7C0FC433FE for ; Wed, 8 Sep 2021 11:42:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A221661074 for ; Wed, 8 Sep 2021 11:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349176AbhIHLnq (ORCPT ); Wed, 8 Sep 2021 07:43:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25977 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235453AbhIHLnp (ORCPT ); Wed, 8 Sep 2021 07:43:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631101356; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=0OKWbveyBp4LK+jfSbX2BcrMPG8lLWS9NwmPSKg8Irs=; b=F5vy7fjHl5FnZhs4m556q5of0cr3m6XhmSDAj2x1WtAgea+s6hc1fS/F7h/Ubdph1jTgDH 8AkysnC81NAGSZWtQa3BB73ziEhdpYItviJ0POpqp5dgV5qZZXApJJ4bd3H9N3DyFFd7uS cSiRWwXDNuYjpnSLpCKNvjx1T4JZtfI= 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-315-20EbSMTJPlid_wF6ZA4jZg-1; Wed, 08 Sep 2021 07:42:35 -0400 X-MC-Unique: 20EbSMTJPlid_wF6ZA4jZg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BCCF8835DE0; Wed, 8 Sep 2021 11:42:34 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.192.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id AC24560C17; Wed, 8 Sep 2021 11:42:29 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: "Michael S. Tsirkin" , Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH] vhost_net: fix OoB on sendmsg() failure. Date: Wed, 8 Sep 2021 13:42:09 +0200 Message-Id: <463c1b02ca6f65fc1183431d8d85ec8154a2c28e.1631090797.git.pabeni@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If the sendmsg() call in vhost_tx_batch() fails, both the 'batched_xdp' and 'done_idx' indexes are left unchanged. If such failure happens when batched_xdp == VHOST_NET_BATCH, the next call to vhost_net_build_xdp() will access and write memory outside the xdp buffers area. Since sendmsg() can only error with EBADFD, this change addresses the issue explicitly freeing the XDP buffers batch on error. Fixes: 0a0be13b8fe2 ("vhost_net: batch submitting XDP buffers to underlayer sockets") Suggested-by: Jason Wang Signed-off-by: Paolo Abeni Acked-by: Jason Wang --- Note: my understanding is that this should go through MST's tree, please educate me otherwise, thanks! --- drivers/vhost/net.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 3a249ee7e144..28ef323882fb 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -467,7 +467,7 @@ static void vhost_tx_batch(struct vhost_net *net, .num = nvq->batched_xdp, .ptr = nvq->xdp, }; - int err; + int i, err; if (nvq->batched_xdp == 0) goto signal_used; @@ -476,6 +476,15 @@ static void vhost_tx_batch(struct vhost_net *net, err = sock->ops->sendmsg(sock, msghdr, 0); if (unlikely(err < 0)) { vq_err(&nvq->vq, "Fail to batch sending packets\n"); + + /* free pages owned by XDP; since this is an unlikely error path, + * keep it simple and avoid more complex bulk update for the + * used pages + */ + for (i = 0; i < nvq->batched_xdp; ++i) + put_page(virt_to_head_page(nvq->xdp[i].data)); + nvq->batched_xdp = 0; + nvq->done_idx = 0; return; }