From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH v2 2/2] virtio-net: Prevent NULL dereference Date: Wed, 28 Sep 2011 17:40:55 +0300 Message-ID: <1317220855-9352-2-git-send-email-levinsasha928@gmail.com> References: <1317220855-9352-1-git-send-email-levinsasha928@gmail.com> Cc: Sasha Levin , Rusty Russell , "Michael S. Tsirkin" , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1317220855-9352-1-git-send-email-levinsasha928@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This patch prevents a NULL dereference when the user has passed a length longer than an actual buffer to virtio-net. Cc: Rusty Russell Cc: "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Cc: kvm@vger.kernel.org Signed-off-by: Sasha Levin --- drivers/net/virtio_net.c | 12 +++++++++++- 1 files changed, 11 insertions(+), 1 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index bde0dec..4a53d2a 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -208,12 +208,22 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, return NULL; } - while (len) { + while (len && page) { set_skb_frag(skb, page, offset, &len); page = (struct page *)page->private; offset = 0; } + /* + * This is the case where we ran out of pages in our linked list, but + * supposedly have more data to read. + */ + if (len > 0) { + pr_debug("%s: missing data to assemble skb\n", skb->dev->name); + dev_kfree_skb(skb); + return NULL; + } + if (page) give_pages(vi, page); -- 1.7.6.1