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, 127 insertions, 0 deletions

diff --git a/Documentation/admin-guide/laptops/alienware-wmi.rst b/Documentation/admin-guide/laptops/alienware-wmi.rst
new file mode 100644
index 000000000..e532c60db
--- /dev/null
+++ b/Documentation/admin-guide/laptops/alienware-wmi.rst
@@ -0,0 +1,127 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+====================
+Alienware WMI Driver
+====================
+
+Kurt Borja <kuurtb@gmail.com>
+
+This is a driver for the "WMAX" WMI device, which is found in most Dell gaming
+laptops and controls various special features.
+
+Before the launch of M-Series laptops (~2018), the "WMAX" device controlled
+basic RGB lighting, deep sleep mode, HDMI mode and amplifier status.
+
+Later, this device was completely repurpused. Now it mostly deals with thermal
+profiles, sensor monitoring and overclocking. This interface is named "AWCC" and
+is known to be used by the AWCC OEM application to control these features.
+
+The alienware-wmi driver controls both interfaces.
+
+AWCC Interface
+==============
+
+WMI device documentation: Documentation/wmi/devices/alienware-wmi.rst
+
+Supported devices
+-----------------
+
+- Alienware M-Series laptops
+- Alienware X-Series laptops
+- Alienware Aurora Desktops
+- Dell G-Series laptops
+
+If you believe your device supports the AWCC interface and you don't have any of
+the features described in this document, try the following alienware-wmi module
+parameters:
+
+- ``force_platform_profile=1``: Forces probing for platform profile support
+- ``force_hwmon=1``: Forces probing for HWMON support
+
+If the module loads successfully with these parameters, consider submitting a
+patch adding your model to the ``awcc_dmi_table`` located in
+``drivers/platform/x86/dell/alienware-wmi-wmax.c`` or contacting the maintainer
+for further guidance.
+
+Status
+------
+
+The following features are currently supported:
+
+- :ref:`Platform Profile <platform-profile>`:
+
+  - Thermal profile control
+
+  - G-Mode toggling
+
+- :ref:`HWMON <hwmon>`:
+
+  - Sensor monitoring
+
+  - Manual fan control
+
+.. _platform-profile:
+
+Platform Profile
+----------------
+
+The AWCC interface exposes various firmware defined thermal profiles. These are
+exposed to user-space through the Platform Profile class interface. Refer to
+:ref:`sysfs-class-platform-profile <abi_file_testing_sysfs_class_platform_profile>`
+for more information.
+
+The name of the platform-profile class device exported by this driver is
+"alienware-wmi" and it's path can be found with:
+
+::
+
+ grep -l "alienware-wmi" /sys/class/platform-profile/platform-profile-*/name | sed 's|/[^/]*$||'
+
+If the device supports G-Mode, it is also toggled when selecting the
+``performance`` profile.
+
+.. note::
+   You may set the ``force_gmode`` module parameter to always try to toggle this
+   feature, without checking if your model supports it.
+
+.. _hwmon:
+
+HWMON
+-----
+
+The AWCC interface also supports sensor monitoring and manual fan control. Both
+of these features are exposed to user-space through the HWMON interface.
+
+The name of the hwmon class device exported by this driver is "alienware_wmi"
+and it's path can be found with:
+
+::
+
+ grep -l "alienware_wmi" /sys/class/hwmon/hwmon*/name | sed 's|/[^/]*$||'
+
+Sensor monitoring is done through the standard HWMON interface. Refer to
+:ref:`sysfs-class-hwmon <abi_file_testing_sysfs_class_hwmon>` for more
+information.
+
+Manual fan control on the other hand, is not exposed directly by the AWCC
+interface. Instead it let's us control a fan `boost` value. This `boost` value
+has the following approximate behavior over the fan pwm:
+
+::
+
+ pwm = pwm_base + (fan_boost / 255) * (pwm_max - pwm_base)
+
+Due to the above behavior, the fan `boost` control is exposed to user-space
+through the following, custom hwmon sysfs attribute:
+
+=============================== ======= =======================================
+Name				Perm	Description
+=============================== ======= =======================================
+fan[1-4]_boost			RW	Fan boost value.
+
+					Integer value between 0 and 255
+=============================== ======= =======================================
+
+.. note::
+   In some devices, manual fan control only works reliably if the ``custom``
+   platform profile is selected.