[ 17/70] usb: feed USB device information to the /dev/random driver

From: Ben Hutchings
Date: Mon Aug 06 2012 - 23:53:19 EST


3.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: Theodore Ts'o <tytso@xxxxxxx>

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@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Greg KH <greg@xxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/core/hub.c | 9 +++++++++
1 file changed, 9 insertions(+)

--- 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 *ud
/* 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


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