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From: Wen Yang <wenyang@linux.alibaba.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Wen Yang <wenyang@linux.alibaba.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Chunfeng Yun <chunfeng.yun@mediatek.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] usb: roles: fix a potential use after free
Date: Sun, 24 Nov 2019 22:22:36 +0800	[thread overview]
Message-ID: <20191124142236.25671-1-wenyang@linux.alibaba.com> (raw)

Free the sw structure only after we are done using it.
This patch just moves the put_device() down a bit to avoid the
use after free.

Fixes: 5c54fcac9a9d ("usb: roles: Take care of driver module reference counting")
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/usb/roles/class.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index 8273126..63a00ff 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -169,8 +169,8 @@ struct usb_role_switch *fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
 void usb_role_switch_put(struct usb_role_switch *sw)
 {
 	if (!IS_ERR_OR_NULL(sw)) {
-		put_device(&sw->dev);
 		module_put(sw->dev.parent->driver->owner);
+		put_device(&sw->dev);
 	}
 }
 EXPORT_SYMBOL_GPL(usb_role_switch_put);
-- 
1.8.3.1


             reply	other threads:[~2019-11-24 14:23 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-24 14:22 Wen Yang [this message]
2019-11-25  9:35 ` [PATCH] usb: roles: fix a potential use after free Peter Chen
2019-11-26 15:49 ` Heikki Krogerus
2019-11-26 15:50   ` Heikki Krogerus

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