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 --- tools/bootconfig/Makefile | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 tools/bootconfig/Makefile (limited to 'tools/bootconfig/Makefile') diff --git a/tools/bootconfig/Makefile b/tools/bootconfig/Makefile new file mode 100644 index 000000000..90eb47c9d --- /dev/null +++ b/tools/bootconfig/Makefile @@ -0,0 +1,30 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for bootconfig command +include ../scripts/Makefile.include + +bindir ?= /usr/bin + +ifeq ($(srctree),) +srctree := $(patsubst %/,%,$(dir $(CURDIR))) +srctree := $(patsubst %/,%,$(dir $(srctree))) +endif + +LIBSRC = $(srctree)/lib/bootconfig.c $(srctree)/include/linux/bootconfig.h +override CFLAGS += -Wall -g -I$(CURDIR)/include + +ALL_TARGETS := bootconfig +ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS)) + +all: $(ALL_PROGRAMS) test + +$(OUTPUT)bootconfig: main.c include/linux/bootconfig.h $(LIBSRC) + $(CC) $(filter %.c,$^) $(CFLAGS) $(LDFLAGS) -o $@ + +test: $(ALL_PROGRAMS) test-bootconfig.sh + ./test-bootconfig.sh $(OUTPUT) + +install: $(ALL_PROGRAMS) + install $(OUTPUT)bootconfig $(DESTDIR)$(bindir) + +clean: + $(RM) -f $(OUTPUT)*.o $(ALL_PROGRAMS) -- cgit v1.3.1