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memtest86plus/boot/header.S

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Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
// SPDX-License-Identifier: GPL-2.0
//
// header.S supports booting directly from a UEFI BIOS or via an intermediate
// bootloader that supports the Linux boot protocol. When booted directly from
// the BIOS, it provides the MS-DOS & PE/COFF headers. When using an intermediate
// bootloader, it provides the first few bytes of the Linux boot header (at the
// end of the boot sector), with the remainder of the header being provided by
// setup.S.
//
Mark EFI image .text section as writable. The EFI image .text section is taken from memtest_shared.bin, which is a combined code and data section. Some recent UEFI BIOSs set the page protection attributes when loading EFI images, so we need to mark this section as both executable and writable to prevent page faults. Fixes issue #413 and should fix issue #377.
2024-08-10 10:11:08 -05:00
// Copyright (C) 2020-2024 Martin Whitaker.
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
//
// Derived from Linux 5.6 arch/x86/boot/header.S:
//
// Copyright (C) 1991, 1992 Linus Torvalds
//
// Based on bootsect.S and setup.S
// modified by more people than can be counted
//
// Rewritten as a common file by H. Peter Anvin (Apr 2007)
#define __ASSEMBLY__
#include "boot.h"
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
#include "peimage.h"
Support direct 64-bit EFI boot.
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# The EFI loader loads the header at ImageBase, so we have to locate the main program
# after that. This means we can't load the main program at HIGH_LOAD_ADDR. Pick a load
# address well away from HIGH_LOAD_ADDR, to avoid overlap when relocating the code.
#define IMAGE_BASE 0x200000
.section ".header", "ax", @progbits
.code16
.globl boot
boot:
# "MZ", the MS-DOS header signature.
.byte 0x4d
.byte 0x5a
# In case we are booted by a legacy BIOS, print an error message.
# Fortunately the MS-DOS header translates to harmless instructions.
ljmp $BOOT_SEG, $(error - boot)
error:
movw %cs, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %ss
xorw %sp, %sp
sti
cld
movw $error_msg, %si
0: lodsb
andb %al, %al
jz wait
movb $0xe, %ah
movw $7, %bx
int $0x10
jmp 0b
wait:
# Allow the user to press a key, then reboot.
xorw %ax, %ax
int $0x16
int $0x19
# int 0x19 should never return. In case it does, invoke the BIOS.
# reset code.
ljmp $0xf000,$0xfff0
# The PE header pointer.
.org 0x3c
.long pe_header
error_msg:
.ascii "This is a UEFI bootable image\r\n"
.ascii "\n"
.asciz "Press any key to reboot\r\n"
pe_header:
.ascii "PE"
.word 0
coff_header:
#ifdef __x86_64__
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.word IMAGE_FILE_MACHINE_X64 # Machine (x86-64)
Support direct 64-bit EFI boot.
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#else
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.word IMAGE_FILE_MACHINE_I386 # Machine (i386)
Support direct 64-bit EFI boot.
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#endif
EFI: Add support for .sbat signature revocations This patch adds a new section, ".sbat", which allows for the revocation of signed binaries given a numeric value representing the set of bugs which allow for arbitrary code execution, and therefore a Secure Boot breakout, in a given family of binaries. In this case, the class is defined as "memtest86+", and the current set of bugs is 1. This doesn't imply that we're aware of bugs currently, merely that when we change it to 2, any bugs that /have/ been discovered have been fixed. Documentation for how SBAT works can be found at the following URLs: https://github.com/rhboot/shim/blob/main/SBAT.md https://github.com/rhboot/shim/blob/main/SBAT.example.md Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:16:31 -05:00
.word 3 # NumberOfSections
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
.long 0 # TimeDateStamp
.long 0 # PointerToSymbolTable
.long 0 # NumberOfSymbols
.word section_table - optional_header # SizeOfOptionalHeader
#ifdef __x86_64__
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.word IMAGE_FILE_DEBUG_STRIPPED \
White space changes to improve readability.
2023-01-31 12:02:28 -06:00
| IMAGE_FILE_LOCAL_SYMS_STRIPPED \
| IMAGE_FILE_LINE_NUMS_STRIPPED \
| IMAGE_FILE_EXECUTABLE_IMAGE # Characteristics
Support direct 64-bit EFI boot.
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#else
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.word IMAGE_FILE_32BIT_MACHINE \
White space changes to improve readability.
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| IMAGE_FILE_DEBUG_STRIPPED \
| IMAGE_FILE_LOCAL_SYMS_STRIPPED \
| IMAGE_FILE_LINE_NUMS_STRIPPED \
| IMAGE_FILE_EXECUTABLE_IMAGE # Characteristics.
Support direct 64-bit EFI boot.
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#endif
optional_header:
#ifdef __x86_64__
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.word IMAGE_NT_OPTIONAL_HDR64_MAGIC # PE32+ format
Support direct 64-bit EFI boot.
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#else
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.word IMAGE_NT_OPTIONAL_HDR32_MAGIC # PE32 format
Support direct 64-bit EFI boot.
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#endif
.byte 0x02 # MajorLinkerVersion
.byte 0x14 # MinorLinkerVersion
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_text_size # SizeOfCode
.long _virt_sbat_size # SizeOfInitializedData
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
.long 0 # SizeOfUninitializedData
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_text_start + 0x1e0 # AddressOfEntryPoint
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_text_start # BaseOfCode
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
#ifndef __x86_64__
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_sbat_start # BaseOfData
Support direct 64-bit EFI boot.
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#endif
extra_header_fields:
#ifdef __x86_64__
.quad IMAGE_BASE # ImageBase
#else
.long IMAGE_BASE # ImageBase
#endif
.long 4096 # SectionAlignment
.long 512 # FileAlignment
.word 0 # MajorOperatingSystemVersion
.word 0 # MinorOperatingSystemVersion
.word 0 # MajorImageVersion
.word 0 # MinorImageVersion
.word 0 # MajorSubsystemVersion
.word 0 # MinorSubsystemVersion
.long 0 # Win32VersionValue
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_img_size # SizeOfImage
Avoid sbverify warning about gap in section table. We have a .setup section in the EFI image that contains the remainder of the Linux boot header and the real-mode setup code to support booting via an intermediate bootloader. This sits between the PE header and the .text section. We don't want the EFI loader to load this section, so simply increase the SizeOfHeader field in the PE header to cover it.
2023-02-02 03:32:47 -06:00
.long _file_head_size # SizeOfHeaders
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
.long 0 # CheckSum
.word 10 # Subsystem (EFI application)
.word 0 # DllCharacteristics
#ifdef __x86_64__
.quad 0 # SizeOfStackReserve
.quad 0 # SizeOfStackCommit
.quad 0 # SizeOfHeapReserve
.quad 0 # SizeOfHeapCommit
#else
.long 0 # SizeOfStackReserve
.long 0 # SizeOfStackCommit
.long 0 # SizeOfHeapReserve
.long 0 # SizeOfHeapCommit
#endif
.long 0 # LoaderFlags
EFI: Add Data Directory space Currently, the PE headers we create in boot/header.S do not allocate space for any Data Directory entries, as they haven't been needed. In order to support signatures and compatibility with some loaders, we need the Data Directory to be populated at least enough to set DataDirectory.Certs and DataDirectory.BaseReloc. This patch extends that space enough to include those entries. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:26:24 -05:00
.long IMAGE_DIRECTORY_ENTRY_DEBUG # NumberOfRvaAndSizes
.long 0 # DataDirectory.Export.VirtualAddress
.long 0 # DataDirectory.Export.Size
.long 0 # DataDirectory.Import.VirtualAddress
.long 0 # DataDirectory.Import.Size
.long 0 # DataDirectory.Resource.VirtualAddress
.long 0 # DataDirectory.Resource.Size
.long 0 # DataDirectory.Exception.VirtualAddress
.long 0 # DataDirectory.Exception.Size
.long 0 # DataDirectory.Certs.VirtualAddress
.long 0 # DataDirectory.Certs.Size
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_reloc_start # DataDirectory.BaseReloc.VirtualAddress
.long _real_reloc_size # DataDirectory.BaseReloc.Size
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
# Section table
section_table:
.ascii ".text"
.byte 0
.byte 0
.byte 0
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_text_size # VirtualSize
.long _virt_text_start # VirtualAddress
.long _file_text_size # SizeOfRawData
.long _file_text_start # PointerToRawData
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
.long 0 # PointerToRelocations
.long 0 # PointerToLineNumbers
.word 0 # NumberOfRelocations
.word 0 # NumberOfLineNumbers
Make header.S use symbolic names for values This changes header.S to use the constants defined in peimage.h to for the values in its structure, making it a lot easier to debug. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:11:21 -05:00
.long IMAGE_SCN_MEM_READ \
Mark EFI image .text section as writable. The EFI image .text section is taken from memtest_shared.bin, which is a combined code and data section. Some recent UEFI BIOSs set the page protection attributes when loading EFI images, so we need to mark this section as both executable and writable to prevent page faults. Fixes issue #413 and should fix issue #377.
2024-08-10 10:11:08 -05:00
| IMAGE_SCN_MEM_WRITE \
White space changes to improve readability.
2023-01-31 12:02:28 -06:00
| IMAGE_SCN_MEM_EXECUTE \
| IMAGE_SCN_CNT_CODE # Characteristics (section flags)
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
EFI: Add a dummy relocation section In the past, we've seen some problems with some EFI loaders refusing to load a binary that has both a .text section with the VMA set and no relocations, when the VMA set to load is already allocated for some other purpose. This patch adds a dummy absolute relocation from 0 to 0, so the loader can always feel like it has done something useful. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:24:59 -05:00
.ascii ".reloc"
.byte 0
.byte 0
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_reloc_size # VirtualSize
.long _virt_reloc_start # VirtualAddress
.long _file_reloc_size # SizeOfRawData
.long _file_reloc_start # PointerToRawData
EFI: Add a dummy relocation section In the past, we've seen some problems with some EFI loaders refusing to load a binary that has both a .text section with the VMA set and no relocations, when the VMA set to load is already allocated for some other purpose. This patch adds a dummy absolute relocation from 0 to 0, so the loader can always feel like it has done something useful. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:24:59 -05:00
.long 0 # PointerToRelocations
.long 0 # PointerToLineNumbers
.word 0 # NumberOfRelocations
.word 0 # NumberOfLineNumbers
.long IMAGE_SCN_MEM_READ \
White space changes to improve readability.
2023-01-31 12:02:28 -06:00
| IMAGE_SCN_CNT_INITIALIZED_DATA # Characteristics (section flags)
EFI: Add a dummy relocation section In the past, we've seen some problems with some EFI loaders refusing to load a binary that has both a .text section with the VMA set and no relocations, when the VMA set to load is already allocated for some other purpose. This patch adds a dummy absolute relocation from 0 to 0, so the loader can always feel like it has done something useful. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:24:59 -05:00
EFI: Add support for .sbat signature revocations This patch adds a new section, ".sbat", which allows for the revocation of signed binaries given a numeric value representing the set of bugs which allow for arbitrary code execution, and therefore a Secure Boot breakout, in a given family of binaries. In this case, the class is defined as "memtest86+", and the current set of bugs is 1. This doesn't imply that we're aware of bugs currently, merely that when we change it to 2, any bugs that /have/ been discovered have been fixed. Documentation for how SBAT works can be found at the following URLs: https://github.com/rhboot/shim/blob/main/SBAT.md https://github.com/rhboot/shim/blob/main/SBAT.example.md Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:16:31 -05:00
.ascii ".sbat"
.byte 0
.byte 0
.byte 0
Fix the virtual memory addresses and sizes in the EFI image headers. When the reloc and sbat sections were added by PR #34, three bugs were introduced: 1. The virtual address and size fields in the PE headers were set to the same values as the raw address and size fields. This is incorrect, because the sections in the image file are aligned on 512 byte boundaries, but when loaded into memory they need to be aligned on 4096 byte boundaries. 2. The value programmed into the SizeOfImage field was too large, as it double-counted the region before the start of the .text section. 3. The value programmed into the SizeOfImage field no longer included the bss size. That potentially allowed the EFI loader to load the image immediately before a reserved region of memory without leaving enough space for the bss section. This commit fixes those bugs by calculating both file and virtual memory offsets & sizes in the ld script. Note that we can't add a bss section to the EFI image because many EFI loaders fail to load images that have uninitialised data sections. Instead the text region size in virtual memory is increased to include the bss size. This fixes issue #243. It also eliminates the gaps between sections observed in issue #202.
2023-01-29 15:52:59 -06:00
.long _virt_sbat_size # VirtualSize
.long _virt_sbat_start # VirtualAddress
.long _file_sbat_size # SizeOfRawData
.long _file_sbat_start # PointerToRawData
EFI: Add support for .sbat signature revocations This patch adds a new section, ".sbat", which allows for the revocation of signed binaries given a numeric value representing the set of bugs which allow for arbitrary code execution, and therefore a Secure Boot breakout, in a given family of binaries. In this case, the class is defined as "memtest86+", and the current set of bugs is 1. This doesn't imply that we're aware of bugs currently, merely that when we change it to 2, any bugs that /have/ been discovered have been fixed. Documentation for how SBAT works can be found at the following URLs: https://github.com/rhboot/shim/blob/main/SBAT.md https://github.com/rhboot/shim/blob/main/SBAT.example.md Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:16:31 -05:00
.long 0 # PointerToRelocations
.long 0 # PointerToLineNumbers
.word 0 # NumberOfRelocations
.word 0 # NumberOfLineNumbers
.long IMAGE_SCN_MEM_READ \
White space changes to improve readability.
2023-01-31 12:02:28 -06:00
| IMAGE_SCN_CNT_INITIALIZED_DATA # Characteristics (section flags)
EFI: Add support for .sbat signature revocations This patch adds a new section, ".sbat", which allows for the revocation of signed binaries given a numeric value representing the set of bugs which allow for arbitrary code execution, and therefore a Secure Boot breakout, in a given family of binaries. In this case, the class is defined as "memtest86+", and the current set of bugs is 1. This doesn't imply that we're aware of bugs currently, merely that when we change it to 2, any bugs that /have/ been discovered have been fixed. Documentation for how SBAT works can be found at the following URLs: https://github.com/rhboot/shim/blob/main/SBAT.md https://github.com/rhboot/shim/blob/main/SBAT.example.md Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:16:31 -05:00
Support direct 64-bit EFI boot.
2020-07-03 16:38:17 -05:00
# Emulate the Linux boot header, to allow loading by intermediate boot loaders.
.org 497
setup_sects:
.byte SETUP_SECS
root_flags:
.word 0
sys_size:
.long _sys_size
ram_size:
.word 0
vid_mode:
.word 0
root_dev:
.word 0
boot_flag:
.word 0xAA55
Fix Pe.OptHdr.SizeOfImage and SizeOfHeaders SizeOfImage is defined as: The size (in bytes) of the image, including all headers, as the image is loaded in memory. It must be a multiple of SectionAlignment. SizeOfHeaders likewise is defined as: The combined size of an MS-DOS stub, PE header, and section headers rounded up to a multiple of FileAlignment. Currently SizeOfImage represents .bss and .text, but it doesn't include .header or .setup, nor any sections we'll add later, and there's nothing enforcing that it matches SectionAlignment. Additionally, since .bss is being set up in our running code and /not/ by the loader, the current value is dangerously high, as in the event there is an error in the section table, it could potentially lead the loader to mark memory allocated at runtime holding user-supplied data by any EFI binary loaded before us as executable. This patch adds a new symbol, _img_end, which is after .text and is rounded up to 4kB (which is also what SectionAlignment is set to). It also adds a local label, anchored with ".org 512", and uses that to set SizeOfHeaders - this will ensure the build fails without outputting and invalid binary if the headers take too much space. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:32:14 -05:00
.org 512
EFI: Add a dummy relocation section In the past, we've seen some problems with some EFI loaders refusing to load a binary that has both a .text section with the VMA set and no relocations, when the VMA set to load is already allocated for some other purpose. This patch adds a dummy absolute relocation from 0 to 0, so the loader can always feel like it has done something useful. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:24:59 -05:00
Fix assembler warning about incorrect type/attributes for .reloc section.
2023-01-31 12:17:33 -06:00
.section ".reloc"
EFI: Add a dummy relocation section In the past, we've seen some problems with some EFI loaders refusing to load a binary that has both a .text section with the VMA set and no relocations, when the VMA set to load is already allocated for some other purpose. This patch adds a dummy absolute relocation from 0 to 0, so the loader can always feel like it has done something useful. Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-31 12:24:59 -05:00
.long 0 // Page RVA
.long 10 // Block Size (2*4+2)
Use the correct name for the relocation type in the EFI image .reloc section. The coding is the same, but IMAGE_REL_AMD64_ABSOLUTE is used for COFF relocations, not for base relocations.
2023-01-31 12:06:15 -06:00
.word (IMAGE_REL_BASED_ABSOLUTE << 12) + 0 // reloc 0 -> 0
EFI: Add support for .sbat signature revocations This patch adds a new section, ".sbat", which allows for the revocation of signed binaries given a numeric value representing the set of bugs which allow for arbitrary code execution, and therefore a Secure Boot breakout, in a given family of binaries. In this case, the class is defined as "memtest86+", and the current set of bugs is 1. This doesn't imply that we're aware of bugs currently, merely that when we change it to 2, any bugs that /have/ been discovered have been fixed. Documentation for how SBAT works can be found at the following URLs: https://github.com/rhboot/shim/blob/main/SBAT.md https://github.com/rhboot/shim/blob/main/SBAT.example.md Signed-off-by: Peter Jones <pjones@redhat.com>
2022-03-30 14:16:31 -05:00
.section ".sbat", "a", @progbits
.incbin "../boot/sbat.csv"
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