usb: feed USB device information to the /dev/random driver

commit b04b3156a20d395a7faa8eed98698d1e17a36000 upstream.

Send the USB device's serial, product, and manufacturer strings to the
/dev/random driver to help seed its pools.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 40815d00e05e1f68e663c51766a7c6fd12ab97f4..953269f83ef8bef6e8889186fa759e8856ac47cf 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -23,6 +23,7 @@
 #include <linux/mutex.h>
 #include <linux/freezer.h>
 #include <linux/pm_runtime.h>
+#include <linux/random.h>
 
 #include <asm/uaccess.h>
 #include <asm/byteorder.h>
@@ -1827,6 +1828,14 @@ int usb_new_device(struct usb_device *udev)
        /* Tell the world! */
        announce_device(udev);
 
+       if (udev->serial)
+               add_device_randomness(udev->serial, strlen(udev->serial));
+       if (udev->product)
+               add_device_randomness(udev->product, strlen(udev->product));
+       if (udev->manufacturer)
+               add_device_randomness(udev->manufacturer,
+                                     strlen(udev->manufacturer));
+
        device_enable_async_suspend(&udev->dev);
        /* Register the device.  The device driver is responsible
         * for configuring the device and invoking the add-device