[v2.6.34-stable 159/165] usb: feed USB device information to the /dev/random driver

From: Paul Gortmaker
Date: Wed Aug 15 2012 - 15:57:43 EST


From: Theodore Ts'o <tytso@xxxxxxx>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------

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: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
drivers/usb/core/hub.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 40815d0..953269f 100644
--- 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
--
1.7.12.rc2

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