From: Ard Biesheuvel <ardb@xxxxxxxxxx> [ Commit 34951f3c28bdf6481d949a20413b2ce7693687b2 upstream ] Describe the code and data of the decompressor binary using separate .text and .data PE/COFF sections, so that we will be able to map them using restricted permissions once we increase the section and file alignment sufficiently. This avoids the need for memory mappings that are writable and executable at the same time, which is something that is best avoided for security reasons. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230915171623.655440-17-ardb@xxxxxxxxxx Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/header.S | 19 +++++++++++++++---- 2 files changed, 16 insertions(+), 5 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index b92e00836f69..3c1b3520361c 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -91,7 +91,7 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE SETUP_OBJS = $(addprefix $(obj)/,$(setup-y)) -sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_edata\|z_.*\)$$/\#define ZO_\2 0x\1/p' +sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_e\?data\|z_.*\)$$/\#define ZO_\2 0x\1/p' quiet_cmd_zoffset = ZOFFSET $@ cmd_zoffset = $(NM) $< | sed -n $(sed-zoffset) > $@ diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index a01e55ce506f..178252cdccf5 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -74,9 +74,9 @@ optional_header: .byte 0x02 # MajorLinkerVersion .byte 0x14 # MinorLinkerVersion - .long setup_size + ZO__end - 0x200 # SizeOfCode + .long ZO__data # SizeOfCode - .long 0 # SizeOfInitializedData + .long ZO__end - ZO__data # SizeOfInitializedData .long 0 # SizeOfUninitializedData .long setup_size + ZO_efi_pe_entry # AddressOfEntryPoint @@ -177,9 +177,9 @@ section_table: .byte 0 .byte 0 .byte 0 - .long ZO__end + .long ZO__data .long setup_size - .long ZO__edata # Size of initialized data + .long ZO__data # Size of initialized data # on disk .long setup_size .long 0 # PointerToRelocations @@ -190,6 +190,17 @@ section_table: IMAGE_SCN_MEM_READ | \ IMAGE_SCN_MEM_EXECUTE # Characteristics + .ascii ".data\0\0\0" + .long ZO__end - ZO__data # VirtualSize + .long setup_size + ZO__data # VirtualAddress + .long ZO__edata - ZO__data # SizeOfRawData + .long setup_size + ZO__data # PointerToRawData + + .long 0, 0, 0 + .long IMAGE_SCN_CNT_INITIALIZED_DATA | \ + IMAGE_SCN_MEM_READ | \ + IMAGE_SCN_MEM_WRITE # Characteristics + .set section_count, (. - section_table) / 40 #endif /* CONFIG_EFI_STUB */ -- 2.44.0.769.g3c40516874-goog
