HID: hiddev: fix potential Spectre v1 (4f65245f) · Commits · 戴 / test

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>

drivers/hid/usbhid/hiddev.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -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;

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