[PATCH 3.4 055/172] USB: usbfs: don't leak kernel data in siginfo

lizf
2015-06-16T09:26:23Z

From: Alan Stern <stern@rowland.harvard.edu>

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

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

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: Zefan Li <lizefan@huawei.com>
---
drivers/usb/core/devio.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 371fe69..d2ae3d9 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -444,6 +444,7 @@ 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;
@@ -2091,6 +2092,7 @@ 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;
--
1.9.1