From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall 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 Signed-off-by: Stafford Horne --- Documentation/driver-api/wmi.rst | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 Documentation/driver-api/wmi.rst (limited to 'Documentation/driver-api/wmi.rst') diff --git a/Documentation/driver-api/wmi.rst b/Documentation/driver-api/wmi.rst new file mode 100644 index 000000000..b847bcdcb --- /dev/null +++ b/Documentation/driver-api/wmi.rst @@ -0,0 +1,23 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +============== +WMI Driver API +============== + +The WMI driver core supports a more modern bus-based interface for interacting +with WMI devices, and an older GUID-based interface. The latter interface is +considered to be deprecated, so new WMI drivers should generally avoid it since +it has some issues with multiple WMI devices sharing the same GUID. +The modern bus-based interface instead maps each WMI device to a +:c:type:`struct wmi_device `, so it supports WMI devices sharing the +same GUID. Drivers can then register a :c:type:`struct wmi_driver ` +which will be bound to compatible WMI devices by the driver core. + +.. kernel-doc:: include/linux/wmi.h + :internal: + +.. kernel-doc:: drivers/platform/wmi/string.c + :export: + +.. kernel-doc:: drivers/platform/wmi/core.c + :export: -- cgit v1.3.1