2022-11-22 12:41:27

by Evgeniy Baskov

[permalink] [raw]
Subject: [PATCH v3 07/24] x86/build: Check W^X of vmlinux during build

Check if there are simultaneously writable and executable
program segments in vmlinux ELF image and fail build if there are any.

This would prevent accidental introduction of RWX segments.

Tested-by: Mario Limonciello <[email protected]>
Signed-off-by: Evgeniy Baskov <[email protected]>
---
arch/x86/boot/compressed/Makefile | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 3a261abb6d15..64de6c2b1740 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -112,11 +112,17 @@ vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o
vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o
efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a

+quiet_cmd_wx_check = WXCHK $<
+cmd_wx_check = if $(OBJDUMP) -p $< | grep "flags .wx" > /dev/null; \
+ then (echo >&2 "$<: Simultaneously writable and executable sections are prohibited"; \
+ /bin/false); fi
+
$(obj)/vmlinux: $(vmlinux-objs-y) $(efi-obj-y) FORCE
$(call if_changed,ld)

OBJCOPYFLAGS_vmlinux.bin := -R .comment -S
$(obj)/vmlinux.bin: vmlinux FORCE
+ $(call cmd,wx_check)
$(call if_changed,objcopy)

targets += $(patsubst $(obj)/%,%,$(vmlinux-objs-y)) vmlinux.bin.all vmlinux.relocs
--
2.37.4