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/x86/Makefile_32.cpu | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 arch/x86/Makefile_32.cpu (limited to 'arch/x86/Makefile_32.cpu') diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu new file mode 100644 index 000000000..c5aa169b5 --- /dev/null +++ b/arch/x86/Makefile_32.cpu @@ -0,0 +1,36 @@ +# SPDX-License-Identifier: GPL-2.0 +# CPU tuning section - shared with UML. +# Must change only cflags-y (or [yn]), not CFLAGS! That makes a difference for UML. + +tune = $(call cc-option,-mtune=$(1),$(2)) + +ifdef CONFIG_CC_IS_CLANG +align := -falign-functions=0 $(call cc-option,-falign-jumps=0) $(call cc-option,-falign-loops=0) +else +align := -falign-functions=0 -falign-jumps=0 -falign-loops=0 +endif + +cflags-$(CONFIG_M586TSC) += -march=i586 +cflags-$(CONFIG_M586MMX) += -march=pentium-mmx +cflags-$(CONFIG_M686) += -march=i686 +cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call tune,pentium2) +cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call tune,pentium3) +cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call tune,pentium3) +cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call tune,pentium4) +cflags-$(CONFIG_MK6) += -march=k6 +# Please note, that patches that add -march=athlon-xp and friends are pointless. +# They make zero difference whatsosever to performance at this time. +cflags-$(CONFIG_MK7) += -march=athlon +cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align) +cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align) +cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) $(align) +cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686) +cflags-$(CONFIG_MVIAC7) += -march=i686 +cflags-$(CONFIG_MATOM) += -march=atom + +# Geode GX1 support +cflags-$(CONFIG_MGEODEGX1) += -march=pentium-mmx +cflags-$(CONFIG_MGEODE_LX) += $(call cc-option,-march=geode,-march=pentium-mmx) +# add at the end to overwrite eventual tuning options from earlier +# cpu entries +cflags-$(CONFIG_X86_GENERIC) += $(call tune,generic,$(call tune,i686)) -- cgit v1.3.1