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 --- drivers/firmware/google/Kconfig | 85 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 drivers/firmware/google/Kconfig (limited to 'drivers/firmware/google/Kconfig') diff --git a/drivers/firmware/google/Kconfig b/drivers/firmware/google/Kconfig new file mode 100644 index 000000000..b78c644fa --- /dev/null +++ b/drivers/firmware/google/Kconfig @@ -0,0 +1,85 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig GOOGLE_FIRMWARE + bool "Google Firmware Drivers" + default n + help + These firmware drivers are used by Google servers, + Chromebooks and other devices using coreboot firmware. + If in doubt, say "N". + +if GOOGLE_FIRMWARE + +config GOOGLE_SMI + tristate "SMI interface for Google platforms" + depends on X86 && ACPI && DMI + help + Say Y here if you want to enable SMI callbacks for Google + platforms. This provides an interface for writing to and + clearing the event log. If CONFIG_EFI is also enabled this + driver provides an interface for reading and writing NVRAM + variables. + +config GOOGLE_CBMEM + tristate "CBMEM entries in sysfs" + depends on GOOGLE_COREBOOT_TABLE + help + CBMEM is a downwards-growing memory region created by the + Coreboot BIOS containing tagged data structures from the + BIOS. These data structures expose things like the verified + boot firmware variables, flash layout, firmware event log, + and more. + + This option enables the cbmem module, which causes the + kernel to search for Coreboot CBMEM entries, and expose the + memory for each entry in sysfs under + /sys/bus/coreboot/devices/cbmem-. + +config GOOGLE_COREBOOT_TABLE + tristate "Coreboot Table Access" + depends on HAS_IOMEM && (ACPI || OF) + help + This option enables the coreboot_table module, which provides other + firmware modules access to the coreboot table. The coreboot table + pointer is accessed through the ACPI "GOOGCB00" object or the + device tree node /firmware/coreboot. + If unsure say N. + +config GOOGLE_MEMCONSOLE + tristate + depends on GOOGLE_MEMCONSOLE_X86_LEGACY || GOOGLE_MEMCONSOLE_COREBOOT + +config GOOGLE_MEMCONSOLE_X86_LEGACY + tristate "Firmware Memory Console - X86 Legacy support" + depends on X86 && ACPI && DMI + select GOOGLE_MEMCONSOLE + help + This option enables the kernel to search for a firmware log in + the EBDA on Google servers. If found, this log is exported to + userland in the file /sys/firmware/log. + +config GOOGLE_FRAMEBUFFER_COREBOOT + tristate "Coreboot Framebuffer" + depends on GOOGLE_COREBOOT_TABLE + help + This option enables the kernel to search for a framebuffer in + the coreboot table. If found, it is registered with a platform + device of type coreboot-framebuffer. Using the old device of + type simple-framebuffer is deprecated. + +config GOOGLE_MEMCONSOLE_COREBOOT + tristate "Firmware Memory Console" + depends on GOOGLE_COREBOOT_TABLE + select GOOGLE_MEMCONSOLE + help + This option enables the kernel to search for a firmware log in + the coreboot table. If found, this log is exported to userland + in the file /sys/firmware/log. + +config GOOGLE_VPD + tristate "Vital Product Data" + depends on GOOGLE_COREBOOT_TABLE + help + This option enables the kernel to expose the content of Google VPD + under /sys/firmware/vpd. + +endif # GOOGLE_FIRMWARE -- cgit v1.3.1