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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 DF04CC47240 for ; Thu, 3 Jun 2021 00:42:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF5246139A for ; Thu, 3 Jun 2021 00:42:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229921AbhFCAnn (ORCPT ); Wed, 2 Jun 2021 20:43:43 -0400 Received: from mga11.intel.com ([192.55.52.93]:55025 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229813AbhFCAnb (ORCPT ); Wed, 2 Jun 2021 20:43:31 -0400 IronPort-SDR: DinTgN8Xgx81EUEfgsisb9AyAuB5fomHfIIL//y7wdwQuW55Yww/72anlkraSGz7lSL6aZVilr ZHIq1WZVR2tg== X-IronPort-AV: E=McAfee;i="6200,9189,10003"; a="200919113" X-IronPort-AV: E=Sophos;i="5.83,244,1616482800"; d="scan'208";a="200919113" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2021 17:41:46 -0700 IronPort-SDR: 2pFejv7yOdCVkt/FpXsrK39AE0n8XlGFbMG7ggDFwWorVajHKUYwALrKujQ9Giok8owwu3kAMW bk1Ny78Bc9jg== X-IronPort-AV: E=Sophos;i="5.83,244,1616482800"; d="scan'208";a="549686683" Received: from tassilo.jf.intel.com ([10.54.74.11]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2021 17:41:44 -0700 From: Andi Kleen To: mst@redhat.com Cc: jasowang@redhat.com, virtualization@lists.linux-foundation.org, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, iommu@lists.linux-foundation.org, x86@kernel.org, sathyanarayanan.kuppuswamy@linux.intel.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, Andi Kleen Subject: [PATCH v1 8/8] virtio: Error out on endless free lists Date: Wed, 2 Jun 2021 17:41:33 -0700 Message-Id: <20210603004133.4079390-9-ak@linux.intel.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20210603004133.4079390-1-ak@linux.intel.com> References: <20210603004133.4079390-1-ak@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Error out with a warning when the free list loops longer than the maximum size while freeing descriptors. While technically we don't care about DOS it is still better to abort it early. We ran into this problem while fuzzing the virtio interactions where the fuzzed code would get stuck for a long time. Signed-off-by: Andi Kleen --- drivers/virtio/virtio_ring.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 244a5b62d85c..96adaa4c5404 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -685,6 +685,11 @@ static int detach_buf_split(struct vring_virtqueue *vq, unsigned int head, if (!inside_split_ring(vq, i)) return -EIO; vq->vq.num_free++; + if (WARN_ONCE(vq->vq.num_free > + vq->split.queue_size_in_bytes / + sizeof(struct vring_desc), + "Virtio freelist corrupted")) + return -EIO; } vring_unmap_one_split(vq, &vq->split.vring.desc[i]); -- 2.25.4