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 --- arch/xtensa/Makefile | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 arch/xtensa/Makefile (limited to 'arch/xtensa/Makefile') diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile new file mode 100644 index 000000000..4c14a0217 --- /dev/null +++ b/arch/xtensa/Makefile @@ -0,0 +1,77 @@ +# +# This file is subject to the terms and conditions of the GNU General Public +# License. See the file "COPYING" in the main directory of this archive +# for more details. +# +# Copyright (C) 2001 - 2005 Tensilica Inc. +# Copyright (C) 2014 Cadence Design Systems Inc. +# +# This file is included by the global makefile so that you can add your own +# architecture-specific flags and dependencies. + +# Core configuration. +# (Use VAR= to use another default compiler.) + +variant-y := $(CONFIG_XTENSA_VARIANT_NAME) + +VARIANT = $(variant-y) + +ifneq ($(VARIANT),) + ifdef cross_compiling + ifndef CROSS_COMPILE + CROSS_COMPILE = xtensa_$(VARIANT)- + endif + endif +endif + +# Platform configuration + +platform-$(CONFIG_XTENSA_PLATFORM_XT2000) := xt2000 +platform-$(CONFIG_XTENSA_PLATFORM_ISS) := iss +platform-$(CONFIG_XTENSA_PLATFORM_XTFPGA) := xtfpga + +# temporarily until string.h is fixed +KBUILD_CFLAGS += -ffreestanding -D__linux__ +KBUILD_CFLAGS += -pipe -mlongcalls -mtext-section-literals +KBUILD_CFLAGS += $(call cc-option,-mforce-no-pic,) +KBUILD_CFLAGS += $(call cc-option,-mno-serialize-volatile,) +KBUILD_CFLAGS += $(call cc-option,-mno-fdpic,) +ifneq ($(CONFIG_KERNEL_ABI_CALL0),) +KBUILD_CFLAGS += -mabi=call0 +KBUILD_AFLAGS += -mabi=call0 +endif + +KBUILD_AFLAGS += -mlongcalls -mtext-section-literals +KBUILD_AFLAGS += $(call cc-option,-mno-fdpic,) + +KBUILD_LDFLAGS += -m elf32xtensa + +ifneq ($(CONFIG_LD_NO_RELAX),) +KBUILD_LDFLAGS += --no-relax +endif + +CHECKFLAGS += -D$(if $(CONFIG_CPU_BIG_ENDIAN),__XTENSA_EB__,__XTENSA_EL__) + +vardirs := $(patsubst %,arch/xtensa/variants/%/,$(variant-y)) +plfdirs := $(patsubst %,arch/xtensa/platforms/%/,$(platform-y)) + +KBUILD_CPPFLAGS += $(patsubst %,-I$(srctree)/%include,$(vardirs) $(plfdirs)) + +KBUILD_DEFCONFIG := iss_defconfig + +libs-y += arch/xtensa/lib/ + +boot := arch/xtensa/boot + +all Image zImage uImage xipImage: vmlinux + $(Q)$(MAKE) $(build)=$(boot) $@ + +archheaders: + $(Q)$(MAKE) $(build)=arch/xtensa/kernel/syscalls all + +define archhelp + @echo '* Image - Kernel ELF image with reset vector' + @echo '* zImage - Compressed kernel image (arch/xtensa/boot/images/zImage.*)' + @echo '* uImage - U-Boot wrapped image' + @echo ' xipImage - XIP image' +endef -- cgit v1.3.1