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Message-Id: <20170110131522.967973668@linuxfoundation.org>
Date:   Tue, 10 Jan 2017 14:36:24 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Andrey Konovalov <andreyknvl@...gle.com>,
        Felipe Balbi <felipe.balbi@...ux.intel.com>
Subject: [PATCH 4.4 011/101] usb: gadgetfs: restrict upper bound on device configuration size
4.4-stable review patch.  If anyone has any objections, please let me know.
------------------
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
commit 0994b0a257557e18ee8f0b7c5f0f73fe2b54eec1 upstream.
Andrey Konovalov reported that we were not properly checking the upper
limit before of a device configuration size before calling
memdup_user(), which could cause some problems.
So set the upper limit to PAGE_SIZE * 4, which should be good enough for
all devices.
Reported-by: Andrey Konovalov <andreyknvl@...gle.com>
Signed-off-by: Felipe Balbi <felipe.balbi@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/gadget/legacy/inode.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1783,7 +1783,8 @@ dev_config (struct file *fd, const char
 	}
 	spin_unlock_irq(&dev->lock);
 
-	if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
+	if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
+	    (len > PAGE_SIZE * 4))
 		return -EINVAL;
 
 	/* we might need to change message format someday */
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