linux-kernel - [PATCH 4.9 33/54] usb: gadget: ether: Fix race between gether_disconnect and rx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190718030052.008794590@linuxfoundation.org>
Date:   Thu, 18 Jul 2019 12:02:03 +0900
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Kiruthika Varadarajan <Kiruthika.Varadarajan@...man.com>,
        Felipe Balbi <felipe.balbi@...ux.intel.com>
Subject: [PATCH 4.9 33/54] usb: gadget: ether: Fix race between gether_disconnect and rx_submit

From: Kiruthika Varadarajan <Kiruthika.Varadarajan@...man.com>

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@...r.kernel.org>
Signed-off-by: Kiruthika Varadarajan <Kiruthika.Varadarajan@...man.com>
Signed-off-by: Felipe Balbi <felipe.balbi@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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
@@ -198,11 +198,12 @@ 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;
@@ -223,6 +224,7 @@ 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) {