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/Makefile.vmlinux_o | 95 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 scripts/Makefile.vmlinux_o (limited to 'scripts/Makefile.vmlinux_o') diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o new file mode 100644 index 000000000..527352c22 --- /dev/null +++ b/scripts/Makefile.vmlinux_o @@ -0,0 +1,95 @@ +# SPDX-License-Identifier: GPL-2.0-only + +PHONY := __default +__default: vmlinux.o + +include include/config/auto.conf +include $(srctree)/scripts/Kbuild.include + +# for objtool +include $(srctree)/scripts/Makefile.lib + +# Generate a linker script to ensure correct ordering of initcalls for Clang LTO +# --------------------------------------------------------------------------- + +quiet_cmd_gen_initcalls_lds = GEN $@ + cmd_gen_initcalls_lds = \ + $(PYTHON3) $(srctree)/scripts/jobserver-exec \ + $(PERL) $(real-prereqs) > $@ + +.tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \ + vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE + $(call if_changed,gen_initcalls_lds) + +targets := .tmp_initcalls.lds + +ifdef CONFIG_LTO_CLANG +initcalls-lds := .tmp_initcalls.lds +endif + +# objtool for vmlinux.o +# --------------------------------------------------------------------------- +# +# For delay-objtool (IBT or LTO), objtool doesn't run on individual translation +# units. Instead it runs on vmlinux.o. +# +# For !delay-objtool + CONFIG_NOINSTR_VALIDATION, it runs on both translation +# units and vmlinux.o, with the latter only used for noinstr/unret validation. + +objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION)) + +ifeq ($(delay-objtool),y) +vmlinux-objtool-args-y += $(objtool-args-y) +else +vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR) += --werror +endif + +vmlinux-objtool-args-$(CONFIG_NOINSTR_VALIDATION) += --noinstr \ + $(if $(or $(CONFIG_MITIGATION_UNRET_ENTRY),$(CONFIG_MITIGATION_SRSO)), --unret) + +objtool-args = $(vmlinux-objtool-args-y) --link + +# Link of vmlinux.o used for section mismatch analysis +# --------------------------------------------------------------------------- + +vmlinux-o-ld-args-$(CONFIG_BUILTIN_MODULE_RANGES) += -Map=$@.map + +quiet_cmd_ld_vmlinux.o = LD $@ + cmd_ld_vmlinux.o = \ + $(LD) ${KBUILD_LDFLAGS} -r -o $@ \ + $(vmlinux-o-ld-args-y) \ + $(addprefix -T , $(initcalls-lds)) \ + --whole-archive vmlinux.a --no-whole-archive \ + --start-group $(KBUILD_VMLINUX_LIBS) --end-group \ + $(cmd_objtool) + +cmd_check_function_names = $(srctree)/scripts/check-function-names.sh $@ + +define rule_ld_vmlinux.o + $(call cmd_and_savecmd,ld_vmlinux.o) + $(call cmd,gen_objtooldep) + $(call cmd,check_function_names) +endef + + +vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE + $(call if_changed_rule,ld_vmlinux.o) + +targets += vmlinux.o + +# Add FORCE to the prerequisites of a target to force it to be always rebuilt. +# --------------------------------------------------------------------------- + +PHONY += FORCE +FORCE: + +# Read all saved command lines and dependencies for the $(targets) we +# may be building above, using $(if_changed{,_dep}). As an +# optimization, we don't need to read them if the target does not +# exist, we will rebuild anyway in that case. + +existing-targets := $(wildcard $(sort $(targets))) + +-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) + +.PHONY: $(PHONY) -- cgit v1.3.1