Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wei Xu , Matthew Rosato , "Michael S. Tsirkin" , "David S. Miller" Subject: [PATCH 4.14 25/52] tap: free skb if flags error Date: Fri, 15 Dec 2017 10:52:02 +0100 Message-Id: <20171215092309.840556849@linuxfoundation.org> In-Reply-To: <20171215092308.500651185@linuxfoundation.org> References: <20171215092308.500651185@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wei Xu [ Upstream commit 61d78537843e676e7f56ac6db333db0c0529b892 ] tap_recvmsg() supports accepting skb by msg_control after commit 3b4ba04acca8 ("tap: support receiving skb from msg_control"), the skb if presented should be freed within the function, otherwise it would be leaked. Signed-off-by: Wei Xu Reported-by: Matthew Rosato Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/tap.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -829,8 +829,11 @@ static ssize_t tap_do_read(struct tap_qu DEFINE_WAIT(wait); ssize_t ret = 0; - if (!iov_iter_count(to)) + if (!iov_iter_count(to)) { + if (skb) + kfree_skb(skb); return 0; + } if (skb) goto put; @@ -1154,11 +1157,14 @@ static int tap_recvmsg(struct socket *so size_t total_len, int flags) { struct tap_queue *q = container_of(sock, struct tap_queue, sock); + struct sk_buff *skb = m->msg_control; int ret; - if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) + if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) { + if (skb) + kfree_skb(skb); return -EINVAL; - ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, - m->msg_control); + } + ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb); if (ret > total_len) { m->msg_flags |= MSG_TRUNC; ret = flags & MSG_TRUNC ? ret : total_len;