Commit d1c0272b authored by Kees Cook's avatar Kees Cook Committed by Ingo Molnar
Browse files

x86/boot/compressed: Remove, discard, or assert for unwanted sections 



In preparation for warning on orphan sections, stop the linker from
generating the .eh_frame* sections, discard unwanted non-zero-sized
generated sections, and enforce other expected-to-be-zero-sized sections
(since discarding them might hide problems with them suddenly gaining
unexpected entries).

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-28-keescook@chromium.org
parent 7cf891a4

arch/x86/boot/compressed/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ GCOV_PROFILE := n 
UBSAN_SANITIZE :=n



KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)

KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)

# Compressed kernel should be built as PIE since it may be loaded at any

# address by the bootloader.

LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)

arch/x86/boot/compressed/vmlinux.lds.S

+12 −2
Original line number Diff line number Diff line
@@ -72,6 +72,11 @@ SECTIONS 
	ELF_DETAILS



	DISCARDS

	/DISCARD/ : {

		*(.dynamic) *(.dynsym) *(.dynstr) *(.dynbss)

		*(.hash) *(.gnu.hash)

		*(.note.*)

	}



	.got.plt (INFO) : {

		*(.got.plt)
@@ -93,13 +98,18 @@ SECTIONS 
	}

	ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!")



	.plt : {

		*(.plt) *(.plt.*)

	}

	ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")



	.rel.dyn : {

		*(.rel.*)

		*(.rel.*) *(.rel_*)

	}

	ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!")



	.rela.dyn : {

		*(.rela.*)

		*(.rela.*) *(.rela_*)

	}

	ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!")

}

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