usb: gadgetfs: restrict upper bound on device configuration size

commit 0994b0a 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 <[email protected]> Signed-off-by: Felipe Balbi <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
linaro-swg · Jan 12, 2017 · 404954e · 404954e
1 parent 72271ae
commit 404954e
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
@@ -1762,7 +1762,8 @@ dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 	}
 	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 */