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, 40 insertions, 0 deletions

diff --git a/drivers/hid/surface-hid/Kconfig b/drivers/hid/surface-hid/Kconfig
new file mode 100644
index 000000000..d0cfd0d29
--- /dev/null
+++ b/drivers/hid/surface-hid/Kconfig
@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: GPL-2.0+
+menu "Surface System Aggregator Module HID support"
+	depends on SURFACE_AGGREGATOR
+
+config SURFACE_HID
+	tristate "HID transport driver for Surface System Aggregator Module"
+	depends on SURFACE_AGGREGATOR_REGISTRY
+	select SURFACE_HID_CORE
+	help
+	  Driver to support integrated HID devices on newer Microsoft Surface
+	  models.
+
+	  This driver provides support for the HID transport protocol provided
+	  by the Surface Aggregator Module (i.e. the embedded controller) on
+	  7th-generation Microsoft Surface devices, i.e. Surface Book 3 and
+	  Surface Laptop 3. On those models, it is mainly used to connect the
+	  integrated touchpad and keyboard.
+
+	  Say M or Y here, if you want support for integrated HID devices, i.e.
+	  integrated touchpad and keyboard, on 7th generation Microsoft Surface
+	  models.
+
+config SURFACE_KBD
+	tristate "HID keyboard transport driver for Surface System Aggregator Module"
+	select SURFACE_HID_CORE
+	help
+	  Driver to support HID keyboards on Surface Laptop 1 and 2 devices.
+
+	  This driver provides support for the HID transport protocol provided
+	  by the Surface Aggregator Module (i.e. the embedded controller) on
+	  Microsoft Surface Laptops 1 and 2. It is used to connect the
+	  integrated keyboard on those devices.
+
+	  Say M or Y here, if you want support for the integrated keyboard on
+	  Microsoft Surface Laptops 1 and 2.
+
+endmenu
+
+config SURFACE_HID_CORE
+	tristate