[PATCH 3.2 067/221] USB: usbfs: don't leak kernel data in siginfo

[Ben Hutchings]

3.2.69-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

commit f0c2b68198589249afd2b1f2c4e8de8c03e19c16 upstream.

When a signal is delivered, the information in the siginfo structure
is copied to userspace.  Good security practice dicatates that the
unused fields in this structure should be initialized to 0 so that
random kernel stack data isn't exposed to the user.  This patch adds
such an initialization to the two places where usbfs raises signals.

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reported-by: Dave Mielke <dave@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/core/devio.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -406,6 +406,7 @@ static void async_completed(struct urb *
 	as->status = urb->status;
 	signr = as->signr;
 	if (signr) {
+		memset(&sinfo, 0, sizeof(sinfo));
 		sinfo.si_signo = as->signr;
 		sinfo.si_errno = as->status;
 		sinfo.si_code = SI_ASYNCIO;
@@ -2031,6 +2032,7 @@ static void usbdev_remove(struct usb_dev
 		wake_up_all(&ps->wait);
 		list_del_init(&ps->list);
 		if (ps->discsignr) {
+			memset(&sinfo, 0, sizeof(sinfo));
 			sinfo.si_signo = ps->discsignr;
 			sinfo.si_errno = EPIPE;
 			sinfo.si_code = SI_ASYNCIO;

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