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 --- scripts/Makefile.clang | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 scripts/Makefile.clang (limited to 'scripts/Makefile.clang') diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang new file mode 100644 index 000000000..b67636b28 --- /dev/null +++ b/scripts/Makefile.clang @@ -0,0 +1,42 @@ +# Individual arch/{arch}/Makefiles should use -EL/-EB to set intended +# endianness and -m32/-m64 to set word size based on Kconfigs instead of +# relying on the target triple. +CLANG_TARGET_FLAGS_arm := arm-linux-gnueabi +CLANG_TARGET_FLAGS_arm64 := aarch64-linux-gnu +CLANG_TARGET_FLAGS_hexagon := hexagon-linux-musl +CLANG_TARGET_FLAGS_loongarch := loongarch64-linux-gnusf +CLANG_TARGET_FLAGS_m68k := m68k-linux-gnu +CLANG_TARGET_FLAGS_mips := mipsel-linux-gnu +CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu +CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu +CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu +CLANG_TARGET_FLAGS_sparc := sparc64-linux-gnu +CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu +# This is only for i386 UM builds, which need the 32-bit target not -m32 +CLANG_TARGET_FLAGS_i386 := i386-linux-gnu +CLANG_TARGET_FLAGS_um := $(CLANG_TARGET_FLAGS_$(SUBARCH)) +CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH)) + +ifeq ($(CLANG_TARGET_FLAGS),) +$(error add '--target=' option to scripts/Makefile.clang) +else +CLANG_FLAGS += --target=$(CLANG_TARGET_FLAGS) +endif + +ifeq ($(LLVM_IAS),0) +CLANG_FLAGS += -fno-integrated-as +GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) +CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) +else +CLANG_FLAGS += -fintegrated-as +endif +# By default, clang only warns when it encounters an unknown warning flag or +# certain optimization flags it knows it has not implemented. +# Make it behave more like gcc by erroring when these flags are encountered +# so they can be implemented or wrapped in cc-option. +CLANG_FLAGS += -Werror=unknown-warning-option +CLANG_FLAGS += -Werror=ignored-optimization-argument +CLANG_FLAGS += -Werror=option-ignored +CLANG_FLAGS += -Werror=unused-command-line-argument +KBUILD_CPPFLAGS += $(CLANG_FLAGS) +export CLANG_FLAGS -- cgit v1.3.1