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/hexagon/Makefile | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 arch/hexagon/Makefile (limited to 'arch/hexagon/Makefile') diff --git a/arch/hexagon/Makefile b/arch/hexagon/Makefile new file mode 100644 index 000000000..ff172cbe5 --- /dev/null +++ b/arch/hexagon/Makefile @@ -0,0 +1,40 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for the Hexagon arch + +KBUILD_DEFCONFIG = comet_defconfig + +# Do not use GP-relative jumps +KBUILD_CFLAGS += -G0 +LDFLAGS_vmlinux += -G0 + +# Do not use single-byte enums; these will overflow. +KBUILD_CFLAGS += -fno-short-enums + +# We must use long-calls: +KBUILD_CFLAGS += -mlong-calls + +# Modules must use either long-calls, or use pic/plt. +# Use long-calls for now, it's easier. And faster. +# KBUILD_CFLAGS_MODULE += -fPIC +# KBUILD_LDFLAGS_MODULE += -shared +KBUILD_CFLAGS_MODULE += -mlong-calls + +cflags-y += $(call cc-option,-mv${CONFIG_HEXAGON_ARCH_VERSION}) +aflags-y += $(call cc-option,-mv${CONFIG_HEXAGON_ARCH_VERSION}) +ldflags-y += $(call cc-option,-mv${CONFIG_HEXAGON_ARCH_VERSION}) + +KBUILD_CFLAGS += $(cflags-y) +KBUILD_AFLAGS += $(aflags-y) +KBUILD_LDFLAGS += $(ldflags-y) + +# Thread-info register will be r19. This value is not configureable; +# it is hard-coded in several files. +TIR_NAME := r19 +KBUILD_CFLAGS += -ffixed-$(TIR_NAME) -DTHREADINFO_REG=$(TIR_NAME) -D__linux__ +KBUILD_AFLAGS += -DTHREADINFO_REG=$(TIR_NAME) + +# Disable HexagonConstExtenders pass for LLVM versions prior to 19.1.0 +# https://github.com/llvm/llvm-project/issues/99714 +ifneq ($(call clang-min-version, 190100),y) +KBUILD_CFLAGS += -mllvm -hexagon-cext=false +endif -- cgit v1.3.1