[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20180710182452.860076552@linuxfoundation.org>
Date: Tue, 10 Jul 2018 20:25:06 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
"Gustavo A. R. Silva" <gustavo@...eddedor.com>,
Jiri Kosina <jkosina@...e.cz>
Subject: [PATCH 4.9 38/52] HID: hiddev: fix potential Spectre v1
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gustavo A. R. Silva <gustavo@...eddedor.com>
commit 4f65245f2d178b9cba48350620d76faa4a098841 upstream.
uref->field_index, uref->usage_index, finfo.field_index and cinfo.index can be
indirectly controlled by user-space, hence leading to a potential exploitation
of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
drivers/hid/usbhid/hiddev.c:473 hiddev_ioctl_usage() warn: potential spectre issue 'report->field' (local cap)
drivers/hid/usbhid/hiddev.c:477 hiddev_ioctl_usage() warn: potential spectre issue 'field->usage' (local cap)
drivers/hid/usbhid/hiddev.c:757 hiddev_ioctl() warn: potential spectre issue 'report->field' (local cap)
drivers/hid/usbhid/hiddev.c:801 hiddev_ioctl() warn: potential spectre issue 'hid->collection' (local cap)
Fix this by sanitizing such structure fields before using them to index
report->field, field->usage and hid->collection
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@...r.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/hid/usbhid/hiddev.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -35,6 +35,7 @@
#include <linux/hiddev.h>
#include <linux/compat.h>
#include <linux/vmalloc.h>
+#include <linux/nospec.h>
#include "usbhid.h"
#ifdef CONFIG_USB_DYNAMIC_MINORS
@@ -478,10 +479,14 @@ static noinline int hiddev_ioctl_usage(s
if (uref->field_index >= report->maxfield)
goto inval;
+ uref->field_index = array_index_nospec(uref->field_index,
+ report->maxfield);
field = report->field[uref->field_index];
if (uref->usage_index >= field->maxusage)
goto inval;
+ uref->usage_index = array_index_nospec(uref->usage_index,
+ field->maxusage);
uref->usage_code = field->usage[uref->usage_index].hid;
@@ -508,6 +513,8 @@ static noinline int hiddev_ioctl_usage(s
if (uref->field_index >= report->maxfield)
goto inval;
+ uref->field_index = array_index_nospec(uref->field_index,
+ report->maxfield);
field = report->field[uref->field_index];
@@ -761,6 +768,8 @@ static long hiddev_ioctl(struct file *fi
if (finfo.field_index >= report->maxfield)
break;
+ finfo.field_index = array_index_nospec(finfo.field_index,
+ report->maxfield);
field = report->field[finfo.field_index];
memset(&finfo, 0, sizeof(finfo));
@@ -801,6 +810,8 @@ static long hiddev_ioctl(struct file *fi
if (cinfo.index >= hid->maxcollection)
break;
+ cinfo.index = array_index_nospec(cinfo.index,
+ hid->maxcollection);
cinfo.type = hid->collection[cinfo.index].type;
cinfo.usage = hid->collection[cinfo.index].usage;
Powered by blists - more mailing lists