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/arm/lib/Makefile | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 arch/arm/lib/Makefile (limited to 'arch/arm/lib/Makefile') diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile new file mode 100644 index 000000000..9295055cd --- /dev/null +++ b/arch/arm/lib/Makefile @@ -0,0 +1,42 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# linux/arch/arm/lib/Makefile +# +# Copyright (C) 1995-2000 Russell King +# + +lib-y := changebit.o csumipv6.o csumpartial.o \ + csumpartialcopy.o csumpartialcopyuser.o clearbit.o \ + delay.o delay-loop.o findbit.o memchr.o memcpy.o \ + memmove.o memset.o setbit.o \ + strchr.o strrchr.o \ + testchangebit.o testclearbit.o testsetbit.o \ + ashldi3.o ashrdi3.o lshrdi3.o muldi3.o \ + ucmpdi2.o lib1funcs.o div64.o \ + io-readsb.o io-writesb.o io-readsl.o io-writesl.o \ + call_with_stack.o bswapsdi2.o + +mmu-y := clear_user.o copy_page.o getuser.o putuser.o \ + copy_from_user.o copy_to_user.o + +ifdef CONFIG_CC_IS_CLANG + lib-y += backtrace-clang.o +else + lib-y += backtrace.o +endif + +# using lib_ here won't override already available weak symbols +obj-$(CONFIG_UACCESS_WITH_MEMCPY) += uaccess_with_memcpy.o + +lib-$(CONFIG_MMU) += $(mmu-y) + +ifeq ($(CONFIG_CPU_32v3),y) + lib-y += io-readsw-armv3.o io-writesw-armv3.o +else + lib-y += io-readsw-armv4.o io-writesw-armv4.o +endif + +$(obj)/csumpartialcopy.o: $(obj)/csumpartialcopygeneric.S +$(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S + +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o -- cgit v1.3.1