USB: usbfs: don't leak kernel data in siginfo

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@rowland.harvard.edu>
Reported-by: Dave Mielke <dave@mielke.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 49257b3..64340f3 100644 (file)
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -406,6 +406,7 @@ static void async_completed(struct urb *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_device *udev)
                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;