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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-06-29 17:08:44 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-11 16:31:31 +0200
commit9be3ce793708c0b2324b632e22a9214586f7757c (patch)
tree5e592f26fc317b4fdadc244f035e33993f878285
parent79ef9243e7febb086542373780d49da1bd32ca6b (diff)
HID: hiddev: fix potential Spectre v1
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@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hid/usbhid/hiddev.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index e3ce233f8bdc..23872d08308c 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -36,6 +36,7 @@
#include <linux/hiddev.h>
#include <linux/compat.h>
#include <linux/vmalloc.h>
+#include <linux/nospec.h>
#include "usbhid.h"
#ifdef CONFIG_USB_DYNAMIC_MINORS
@@ -469,10 +470,14 @@ static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd,
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;
@@ -499,6 +504,8 @@ static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd,
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];
@@ -753,6 +760,8 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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));
@@ -797,6 +806,8 @@ static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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;