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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 175b6bbdd2f623970ec62be1a5c922f02983423d..52340cc35641fad8f7825d78e01ad530ce0ea30b 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -24,6 +24,7 @@
 #include <linux/kthread.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
+#include <linux/random.h>
 
 #include <asm/uaccess.h>
 #include <asm/byteorder.h>
@@ -1897,6 +1898,14 @@ 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