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/gcc-plugins/Makefile | 72 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) create mode 100644 scripts/gcc-plugins/Makefile (limited to 'scripts/gcc-plugins/Makefile') diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile new file mode 100644 index 000000000..05b14aba4 --- /dev/null +++ b/scripts/gcc-plugins/Makefile @@ -0,0 +1,72 @@ +# SPDX-License-Identifier: GPL-2.0 + +$(obj)/randomize_layout_plugin.so: $(obj)/randomize_layout_seed.h +quiet_cmd_create_randomize_layout_seed = SEEDHDR $@ +cmd_create_randomize_layout_seed = \ + SEED=$$(cat $(filter-out FORCE,$^) $@; \ + echo ' * This file is automatically generated. Keep it private.' >> $@; \ + echo ' * Exposing this value will expose the layout of randomized structures.' >> $@; \ + echo ' */' >> $@; \ + echo "const char *randstruct_seed = \"$$SEED\";" >> $@ +$(obj)/randomize_layout_seed.h: $(objtree)/scripts/basic/randstruct.seed FORCE + $(call if_changed,create_randomize_layout_seed) +targets += randomize_layout_seed.h + +# Build rules for plugins +# +# No extra code is needed for single-file plugins. +# For multi-file plugins, use *-objs syntax to list the objects. +# +# If the plugin foo.so is compiled from foo.c and foo2.c, you can do: +# +# foo-objs := foo.o foo2.o + +always-y += $(GCC_PLUGIN) + +GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin) + +plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \ + -include $(srctree)/include/linux/compiler-version.h \ + -DPLUGIN_VERSION=$(call stringify,$(KERNELVERSION)) \ + -I $(GCC_PLUGINS_DIR)/include -I $(obj) \ + -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \ + -ggdb -Wno-narrowing -Wno-unused-variable \ + -Wno-format-diag + +plugin_ldflags = -shared + +plugin-single := $(foreach m, $(GCC_PLUGIN), $(if $($(m:%.so=%-objs)),,$(m))) +plugin-multi := $(filter-out $(plugin-single), $(GCC_PLUGIN)) +plugin-objs := $(sort $(foreach m, $(plugin-multi), $($(m:%.so=%-objs)))) + +targets += $(plugin-single) $(plugin-multi) $(plugin-objs) +clean-files += *.so + +plugin-single := $(addprefix $(obj)/, $(plugin-single)) +plugin-multi := $(addprefix $(obj)/, $(plugin-multi)) +plugin-objs := $(addprefix $(obj)/, $(plugin-objs)) + +quiet_cmd_plugin_cxx_so_c = HOSTCXX $@ + cmd_plugin_cxx_so_c = $(HOSTCXX) $(plugin_cxxflags) $(plugin_ldflags) -o $@ $< + +$(plugin-single): $(obj)/%.so: $(src)/%.c FORCE + $(call if_changed_dep,plugin_cxx_so_c) + +quiet_cmd_plugin_ld_so_o = HOSTLD $@ + cmd_plugin_ld_so_o = $(HOSTCXX) $(plugin_ldflags) -o $@ \ + $(addprefix $(obj)/, $($(target-stem)-objs)) + +$(plugin-multi): FORCE + $(call if_changed,plugin_ld_so_o) +$(foreach m, $(notdir $(plugin-multi)), $(eval $(obj)/$m: $(addprefix $(obj)/, $($(m:%.so=%-objs))))) + +quiet_cmd_plugin_cxx_o_c = HOSTCXX $@ + cmd_plugin_cxx_o_c = $(HOSTCXX) $(plugin_cxxflags) -c -o $@ $< + +$(plugin-objs): $(obj)/%.o: $(src)/%.c FORCE + $(call if_changed_dep,plugin_cxx_o_c) + +$(obj)/../../include/generated/gcc-plugins.h: $(plugin-single) $(plugin-multi) FORCE + $(call if_changed,touch) +always-y += ../../include/generated/gcc-plugins.h -- cgit v1.3.1