From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936463AbdKPRvv (ORCPT ); Thu, 16 Nov 2017 12:51:51 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38012 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760283AbdKPRuH (ORCPT ); Thu, 16 Nov 2017 12:50:07 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Girish Moodalbail , Jason Wang , "David S. Miller" Subject: [PATCH 4.13 23/44] tap: double-free in error path in tap_open() Date: Thu, 16 Nov 2017 18:42:47 +0100 Message-Id: <20171116172824.697559419@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171116172823.336649076@linuxfoundation.org> References: <20171116172823.336649076@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Girish Moodalbail [ Upstream commit 78e0ea6791d7baafb8a0ca82b1bd0c7b3453c919 ] Double free of skb_array in tap module is causing kernel panic. When tap_set_queue() fails we free skb_array right away by calling skb_array_cleanup(). However, later on skb_array_cleanup() is called again by tap_sock_destruct through sock_put(). This patch fixes that issue. Fixes: 362899b8725b35e3 (macvtap: switch to use skb array) Signed-off-by: Girish Moodalbail Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/tap.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -517,6 +517,10 @@ static int tap_open(struct inode *inode, &tap_proto, 0); if (!q) goto err; + if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) { + sk_free(&q->sk); + goto err; + } RCU_INIT_POINTER(q->sock.wq, &q->wq); init_waitqueue_head(&q->wq.wait); @@ -540,22 +544,18 @@ static int tap_open(struct inode *inode, if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG)) sock_set_flag(&q->sk, SOCK_ZEROCOPY); - err = -ENOMEM; - if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) - goto err_array; - err = tap_set_queue(tap, file, q); - if (err) - goto err_queue; + if (err) { + /* tap_sock_destruct() will take care of freeing skb_array */ + goto err_put; + } dev_put(tap->dev); rtnl_unlock(); return err; -err_queue: - skb_array_cleanup(&q->skb_array); -err_array: +err_put: sock_put(&q->sk); err: if (tap)