openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/hid/hid-ortek.c b/drivers/hid/hid-ortek.c
new file mode 100644
index 000000000..f27297269
--- /dev/null
+++ b/drivers/hid/hid-ortek.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for various devices which are apparently based on the same chipset
+ *  from certain vendor which produces chips that contain wrong LogicalMaximum
+ *  value in their HID report descriptor. Currently supported devices are:
+ *
+ *    Ortek PKB-1700
+ *    Ortek WKB-2000
+ *    iHome IMAC-A210S
+ *    Skycable wireless presenter
+ *
+ *  Copyright (c) 2010 Johnathon Harris <jmharris@gmail.com>
+ *  Copyright (c) 2011 Jiri Kosina
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+static const __u8 *ortek_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 56 && rdesc[54] == 0x25 && rdesc[55] == 0x01) {
+		hid_info(hdev, "Fixing up logical maximum in report descriptor (Ortek)\n");
+		rdesc[55] = 0x92;
+	} else if (*rsize >= 54 && rdesc[52] == 0x25 && rdesc[53] == 0x01) {
+		hid_info(hdev, "Fixing up logical maximum in report descriptor (Skycable)\n");
+		rdesc[53] = 0x65;
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id ortek_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_PKB1700) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_WKB2000) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_IHOME_IMAC_A210S) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SKYCABLE, USB_DEVICE_ID_SKYCABLE_WIRELESS_PRESENTER) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ortek_devices);
+
+static struct hid_driver ortek_driver = {
+	.name = "ortek",
+	.id_table = ortek_devices,
+	.report_fixup = ortek_report_fixup
+};
+module_hid_driver(ortek_driver);
+
+MODULE_DESCRIPTION("HID driver for Ortek PKB-1700/WKB-2000/Skycable wireless keyboard and mouse trackpad");
+MODULE_LICENSE("GPL");