From 34951f3c28bdf6481d949a20413b2ce7693687b2 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 15 Sep 2023 17:16:31 +0000 Subject: x86/boot: Split off PE/COFF .data section 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 Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230915171623.655440-17-ardb@google.com --- arch/x86/boot/header.S | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'arch/x86/boot/header.S') diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 9e9641e220a7..a1f986105f00 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -75,9 +75,9 @@ 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 @@ -178,9 +178,9 @@ 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 @@ -191,6 +191,17 @@ 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 */ -- cgit