________________________________________ 发件人: Oliver Neukum <oneukum@xxxxxxxx> 发送时间: 2021年1月5日 0:28 收件人: syzbot; andreyknvl@xxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; gustavoars@xxxxxxxxxx; ingrassia@xxxxxxxxxxxxxx; lee.jones@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; penguin-kernel@xxxxxxxxxxxxxxxxxxx; syzkaller-bugs@xxxxxxxxxxxxxxxx 主题: Re: KASAN: use-after-free Read in service_outstanding_interrupt Am Donnerstag, den 17.12.2020, 19:21 -0800 schrieb syzbot: > syzbot has found a reproducer for the following issue on: > > HEAD commit: 5e60366d Merge tag 'fallthrough-fixes-clang-5.11-rc1' of g.. > git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing > console output: https://syzkaller.appspot.com/x/log.txt?x=12c5b623500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5cea7506b7139727 > dashboard link: https://syzkaller.appspot.com/bug?extid=9e04e2df4a32fb661daf > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=175adf07500000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1672680f500000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: >syzbot+9e04e2df4a32fb661daf@xxxxxxxxxxxxxxxxxxxxxxxxx > >#syz test: https://github.com/google/kasan.git 5e60366d > Hello Oliver this use-after-free still exists，It can be seen from calltrace that it is usb_device's object has been released when disconnect, can add a reference count to usb_device's object to avoid this problem diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 508b1c3f8b73..001cb93da6bf 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -106,6 +106,7 @@ struct wdm_device { struct list_head device_list; int (*manage_power)(struct usb_interface *, int); + struct usb_device *usb_dev; }; static struct usb_driver wdm_driver; @@ -338,6 +339,7 @@ static void free_urbs(struct wdm_device *desc) static void cleanup(struct wdm_device *desc) { + usb_put_dev(desc->usb_dev); kfree(desc->sbuf); kfree(desc->inbuf); kfree(desc->orq); @@ -855,6 +857,7 @@ static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descripto r desc->intf = intf; INIT_WORK(&desc->rxwork, wdm_rxwork); INIT_WORK(&desc->service_outs_intr, service_interrupt_work); + desc->usb_dev = usb_get_dev(interface_to_usbdev(intf)); rv = -EINVAL; if (!usb_endpoint_is_int_in(ep)) >From f51e3c5a202f3abc805edd64b21a68d29dd9d60e Mon Sep 17 >00:00:00 2001 >From: Oliver Neukum <oneukum@xxxxxxxx> >Date: Mon, 4 Jan 2021 17:26:33 +0100 >Subject: [PATCH] cdc-wdm: poison URBs upon disconnect > >We have a chicken and egg issue between interrupt and work. >This should break the cycle. > >Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> >--- >drivers/usb/class/cdc-wdm.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > >diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc->wdm.c >index 02d0cfd23bb2..14eddda35280 100644 >--- a/drivers/usb/class/cdc-wdm.c >+++ b/drivers/usb/class/cdc-wdm.c >@@ -324,9 +324,9 @@ static void wdm_int_callback(struct urb *urb) >static void kill_urbs(struct wdm_device *desc) > { > /* the order here is essential */ >- usb_kill_urb(desc->command); >- usb_kill_urb(desc->validity); >- usb_kill_urb(desc->response); >+ usb_poison_urb(desc->command); >+ usb_poison_urb(desc->validity); >+ usb_poison_urb(desc->response); > } > > static void free_urbs(struct wdm_device *desc) >-- >2.26.2
