Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753181AbdLAOsU (ORCPT ); Fri, 1 Dec 2017 09:48:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52216 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753129AbdLAOsT (ORCPT ); Fri, 1 Dec 2017 09:48:19 -0500 Date: Fri, 1 Dec 2017 16:48:17 +0200 From: "Michael S. Tsirkin" To: wexu@redhat.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jasowang@redhat.com, mjrosato@linux.vnet.ibm.com Subject: Re: [PATCH 2/3] tun: free skb in early errors Message-ID: <20171201164812-mutt-send-email-mst@kernel.org> References: <1512123038-15773-1-git-send-email-wexu@redhat.com> <1512123038-15773-3-git-send-email-wexu@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1512123038-15773-3-git-send-email-wexu@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 01 Dec 2017 14:48:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2389 Lines: 83 On Fri, Dec 01, 2017 at 05:10:37AM -0500, wexu@redhat.com wrote: > From: Wei Xu > > tun_recvmsg() supports accepting skb by msg_control after > commit ac77cfd4258f ("tun: support receiving skb through msg_control"), > the skb if presented should be freed no matter how far it can go > along, otherwise it would be leaked. > > This patch fixes several missed cases. > > Signed-off-by: Wei Xu > Reported-by: Matthew Rosato Acked-by: Michael S. Tsirkin > --- > drivers/net/tun.c | 24 ++++++++++++++++++------ > 1 file changed, 18 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 9574900..4f4a842 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1952,8 +1952,11 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, > > tun_debug(KERN_INFO, tun, "tun_do_read\n"); > > - if (!iov_iter_count(to)) > + if (!iov_iter_count(to)) { > + if (skb) > + kfree_skb(skb); > return 0; > + } > > if (!skb) { > /* Read frames from ring */ > @@ -2069,22 +2072,24 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, > { > struct tun_file *tfile = container_of(sock, struct tun_file, socket); > struct tun_struct *tun = tun_get(tfile); > + struct sk_buff *skb = m->msg_control; > int ret; > > - if (!tun) > - return -EBADFD; > + if (!tun) { > + ret = -EBADFD; > + goto out_free_skb; > + } > > if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { > ret = -EINVAL; > - goto out; > + goto out_put_tun; > } > if (flags & MSG_ERRQUEUE) { > ret = sock_recv_errqueue(sock->sk, m, total_len, > SOL_PACKET, TUN_TX_TIMESTAMP); > goto out; > } > - ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, > - m->msg_control); > + ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, skb); > if (ret > (ssize_t)total_len) { > m->msg_flags |= MSG_TRUNC; > ret = flags & MSG_TRUNC ? ret : total_len; > @@ -2092,6 +2097,13 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, > out: > tun_put(tun); > return ret; > + > +out_put_tun: > + tun_put(tun); > +out_free_skb: > + if (skb) > + kfree_skb(skb); > + return ret; > } > > static int tun_peek_len(struct socket *sock) > -- > 1.8.3.1