From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id CE77A376D for ; Thu, 10 Mar 2016 05:30:16 +0100 (CET) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP; 09 Mar 2016 20:30:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,314,1455004800"; d="scan'208";a="920667232" Received: from yliu-dev.sh.intel.com ([10.239.66.49]) by fmsmga001.fm.intel.com with ESMTP; 09 Mar 2016 20:30:15 -0800 From: Yuanhan Liu To: dev@dpdk.org Date: Thu, 10 Mar 2016 12:32:46 +0800 Message-Id: <1457584366-3036-9-git-send-email-yuanhan.liu@linux.intel.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1457584366-3036-1-git-send-email-yuanhan.liu@linux.intel.com> References: <1455803352-5518-1-git-send-email-yuanhan.liu@linux.intel.com> <1457584366-3036-1-git-send-email-yuanhan.liu@linux.intel.com> Subject: [dpdk-dev] [PATCH v3 8/8] vhost: avoid dead loop chain. X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Mar 2016 04:30:17 -0000 If a malicious guest forges a dead loop chain, it could lead to a dead loop of copying the desc buf to mbuf, which results to all mbuf being exhausted. Add a var nr_desc to avoid such case. Suggested-by: Huawei Xie Signed-off-by: Yuanhan Liu --- lib/librte_vhost/vhost_rxtx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c index 43db6c7..73fab7e 100644 --- a/lib/librte_vhost/vhost_rxtx.c +++ b/lib/librte_vhost/vhost_rxtx.c @@ -743,6 +743,8 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, uint32_t cpy_len; struct rte_mbuf *cur = m, *prev = m; struct virtio_net_hdr *hdr; + /* A counter to avoid desc dead loop chain */ + uint32_t nr_desc = 1; desc = &vq->desc[desc_idx]; if (unlikely(desc->len < vq->vhost_hlen)) @@ -761,7 +763,8 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq, while (desc_avail != 0 || (desc->flags & VRING_DESC_F_NEXT) != 0) { /* This desc reaches to its end, get the next one */ if (desc_avail == 0) { - if (unlikely(desc->next >= vq->size)) + if (unlikely(desc->next >= vq->size || + ++nr_desc >= vq->size)) return -1; desc = &vq->desc[desc->next]; -- 1.9.0