[PATCH 4.4 21/40] usb: gadget: ether: Fix race between gether_disconnect and rx_submit
From: Greg Kroah-Hartman
Date: Wed Jul 17 2019 - 23:17:14 EST
From: Kiruthika Varadarajan <Kiruthika.Varadarajan@xxxxxxxxxx>
commit d29fcf7078bc8be2b6366cbd4418265b53c94fac upstream.
On spin lock release in rx_submit, gether_disconnect get a chance to
run, it makes port_usb NULL, rx_submit access NULL port USB, hence null
pointer crash.
Fixed by releasing the lock in rx_submit after port_usb is used.
Fixes: 2b3d942c4878 ("usb ethernet gadget: split out network core")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Kiruthika Varadarajan <Kiruthika.Varadarajan@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/u_ether.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -207,11 +207,12 @@ rx_submit(struct eth_dev *dev, struct us
out = dev->port_usb->out_ep;
else
out = NULL;
- spin_unlock_irqrestore(&dev->lock, flags);
if (!out)
+ {
+ spin_unlock_irqrestore(&dev->lock, flags);
return -ENOTCONN;
-
+ }
/* Padding up to RX_EXTRA handles minor disagreements with host.
* Normally we use the USB "terminate on short read" convention;
@@ -232,6 +233,7 @@ rx_submit(struct eth_dev *dev, struct us
if (dev->port_usb->is_fixed)
size = max_t(size_t, size, dev->port_usb->fixed_out_len);
+ spin_unlock_irqrestore(&dev->lock, flags);
skb = alloc_skb(size + NET_IP_ALIGN, gfp_flags);
if (skb == NULL) {