Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42D35C433F5 for ; Wed, 24 Nov 2021 12:44:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243741AbhKXMr6 (ORCPT ); Wed, 24 Nov 2021 07:47:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:53242 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344789AbhKXMpi (ORCPT ); Wed, 24 Nov 2021 07:45:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 699336142A; Wed, 24 Nov 2021 12:26:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637756806; bh=zVC7uIJA1A2M9ngdkg+5hMkX9mJwdNK37ujEA8LwYMI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zpy81sPlmgzLsMBmI9mgJaUvuovMZm4pLSpswI1+wrDaWqni56S5xcpmEZQUWPqR9 +Q+MFMKLm4VvCEXLdIDZQHTxKzXRSR+9f9nObyXWj1O8VNYo/EmVpZdwPidxxNgQw8 cyJAPnLeHDYPrSWntSHsnh+lQIk0Rq+hxjUNQx38= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+e4df4e1389e28972e955@syzkaller.appspotmail.com, Ziyang Xuan , Jason Gunthorpe , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 181/251] net: vlan: fix a UAF in vlan_dev_real_dev() Date: Wed, 24 Nov 2021 12:57:03 +0100 Message-Id: <20211124115716.547727004@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115710.214900256@linuxfoundation.org> References: <20211124115710.214900256@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ziyang Xuan [ Upstream commit 563bcbae3ba233c275c244bfce2efe12938f5363 ] The real_dev of a vlan net_device may be freed after unregister_vlan_dev(). Access the real_dev continually by vlan_dev_real_dev() will trigger the UAF problem for the real_dev like following: ================================================================== BUG: KASAN: use-after-free in vlan_dev_real_dev+0xf9/0x120 Call Trace: kasan_report.cold+0x83/0xdf vlan_dev_real_dev+0xf9/0x120 is_eth_port_of_netdev_filter.part.0+0xb1/0x2c0 is_eth_port_of_netdev_filter+0x28/0x40 ib_enum_roce_netdev+0x1a3/0x300 ib_enum_all_roce_netdevs+0xc7/0x140 netdevice_event_work_handler+0x9d/0x210 ... Freed by task 9288: kasan_save_stack+0x1b/0x40 kasan_set_track+0x1c/0x30 kasan_set_free_info+0x20/0x30 __kasan_slab_free+0xfc/0x130 slab_free_freelist_hook+0xdd/0x240 kfree+0xe4/0x690 kvfree+0x42/0x50 device_release+0x9f/0x240 kobject_put+0x1c8/0x530 put_device+0x1b/0x30 free_netdev+0x370/0x540 ppp_destroy_interface+0x313/0x3d0 ... Move the put_device(real_dev) to vlan_dev_free(). Ensure real_dev not be freed before vlan_dev unregistered. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+e4df4e1389e28972e955@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan Reviewed-by: Jason Gunthorpe Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/8021q/vlan.c | 3 --- net/8021q/vlan_dev.c | 3 +++ 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index 0efdf83f78e7a..a8cee80e07a70 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -112,9 +112,6 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head) } vlan_vid_del(real_dev, vlan->vlan_proto, vlan_id); - - /* Get rid of the vlan's reference to real_dev */ - dev_put(real_dev); } int vlan_check_real_dev(struct net_device *real_dev, diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index ed3717dc2d201..d28c22e59996c 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -814,6 +814,9 @@ static void vlan_dev_free(struct net_device *dev) free_percpu(vlan->vlan_pcpu_stats); vlan->vlan_pcpu_stats = NULL; + + /* Get rid of the vlan's reference to real_dev */ + dev_put(vlan->real_dev); } void vlan_setup(struct net_device *dev) -- 2.33.0