linux-kernel - [PATCH] usb: gadget: Add the gserial port checking in gs_start

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>] [day] [month] [year] [list]

Message-Id: <11cb15ff2587d4f38f72bfdb3d5650144ba150ef.1467277321.git.baolin.wang@linaro.org>
Date:	Thu, 30 Jun 2016 17:10:23 +0800
From:	Baolin Wang <baolin.wang@...aro.org>
To:	balbi@...nel.org, gregkh@...uxfoundation.org
Cc:	peter@...leysoftware.com, r.baldyga@...sung.com,
	broonie@...nel.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, baolin.wang@...aro.org
Subject: [PATCH] usb: gadget: Add the gserial port checking in gs_start_tx()

When usb gadget is set gadget serial function, it will be crash in below
situation.

It will clean the 'port->port_usb' pointer in gserial_disconnect() function
when usb link is inactive, but it will release lock for disabling the endpoints
in this function. Druing the lock release period, it maybe complete one request
to issue gs_write_complete()--->gs_start_tx() function, but the 'port->port_usb'
pointer had been set NULL, thus it will be crash in gs_start_tx() function.

This patch adds the 'port->port_usb' pointer checking in gs_start_tx() function
to avoid this situation.

Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
---
 drivers/usb/gadget/function/u_serial.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index 3580f19..66a0910 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -375,10 +375,15 @@ __acquires(&port->port_lock)
 */
 {
 	struct list_head	*pool = &port->write_pool;
-	struct usb_ep		*in = port->port_usb->in;
+	struct usb_ep		*in;
 	int			status = 0;
 	bool			do_tty_wake = false;

+	if (!port->port_usb)
+		return status;
+
+	in = port->port_usb->in;
+
 	while (!port->write_busy && !list_empty(pool)) {
 		struct usb_request	*req;
 		int			len;
-- 
1.7.9.5