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/mod/Makefile | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 scripts/mod/Makefile (limited to 'scripts/mod/Makefile') diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile new file mode 100644 index 000000000..c729bc936 --- /dev/null +++ b/scripts/mod/Makefile @@ -0,0 +1,27 @@ +# SPDX-License-Identifier: GPL-2.0 +CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO) + +hostprogs-always-y += modpost mk_elfconfig +always-y += empty.o + +modpost-objs := modpost.o file2alias.o sumversion.o symsearch.o + +devicetable-offsets-file := devicetable-offsets.h + +$(obj)/$(devicetable-offsets-file): $(obj)/devicetable-offsets.s FORCE + $(call filechk,offsets,__DEVICETABLE_OFFSETS_H__) + +targets += $(devicetable-offsets-file) devicetable-offsets.s + +# dependencies on generated files need to be listed explicitly + +$(obj)/modpost.o $(obj)/file2alias.o $(obj)/sumversion.o $(obj)/symsearch.o: $(obj)/elfconfig.h +$(obj)/file2alias.o: $(obj)/$(devicetable-offsets-file) + +quiet_cmd_elfconfig = MKELF $@ + cmd_elfconfig = $(obj)/mk_elfconfig < $< > $@ + +$(obj)/elfconfig.h: $(obj)/empty.o $(obj)/mk_elfconfig FORCE + $(call if_changed,elfconfig) + +targets += elfconfig.h -- cgit v1.3.1