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Date: Mon, 6 Feb 2017 16:24:34 +0000
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
will.deacon@....com,
catalin.marinas@....com,
mark.rutland@....com
Cc: labbott@...oraproject.org,
kernel-hardening@...ts.openwall.com,
leif.lindholm@...aro.org,
pjones@...hat.com,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: [PATCH 6/7] arm64: efi: replace open coded constants with symbolic ones
Replace open coded constants with symbolic ones throughout the
Image and the EFI headers. Note that in two cases, this removes
a value that the PE/COFF spec does not allow:
- NumberOfSymbols in the PE header should be 0
- PE/COFF executable sections (as opposed to sections in object files)
should not use the section alignment flags
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
arch/arm64/kernel/efi-header.S | 37 ++++++++++----------
arch/arm64/kernel/head.S | 5 +--
2 files changed, 20 insertions(+), 22 deletions(-)
diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S
index 35b11654ecc5..c87c23336c86 100644
--- a/arch/arm64/kernel/efi-header.S
+++ b/arch/arm64/kernel/efi-header.S
@@ -7,6 +7,8 @@
* published by the Free Software Foundation.
*/
+#include <linux/pe.h>
+
.macro __jmp, target
#ifdef CONFIG_EFI
/*
@@ -33,21 +35,20 @@
.long pe_header - _head // Offset to the PE header.
pe_header:
- .ascii "PE"
- .short 0
+ .long PE_MAGIC
coff_header:
- .short 0xaa64 // AArch64
- .short 1 // nr_sections
+ .short IMAGE_FILE_MACHINE_ARM64 // Machine
+ .short 1 // NumberOfSections
.long 0 // TimeDateStamp
.long 0 // PointerToSymbolTable
- .long 1 // NumberOfSymbols
+ .long 0 // NumberOfSymbols
.short section_table - optional_header // SizeOfOptionalHeader
- .short 0x206 // Characteristics.
- // IMAGE_FILE_DEBUG_STRIPPED |
- // IMAGE_FILE_EXECUTABLE_IMAGE |
- // IMAGE_FILE_LINE_NUMS_STRIPPED
+ .short IMAGE_FILE_DEBUG_STRIPPED | \
+ IMAGE_FILE_EXECUTABLE_IMAGE | \
+ IMAGE_FILE_LINE_NUMS_STRIPPED // Characteristics
+
optional_header:
- .short 0x20b // PE32+ format
+ .short PE_OPT_MAGIC_PE32PLUS // PE32+ format
.byte 0x02 // MajorLinkerVersion
.byte 0x14 // MinorLinkerVersion
.long _end - efi_header_end // SizeOfCode
@@ -58,7 +59,7 @@ optional_header:
extra_header_fields:
.quad 0 // ImageBase
- .long 0x1000 // SectionAlignment
+ .long SZ_4K // SectionAlignment
.long PECOFF_FILE_ALIGNMENT // FileAlignment
.short 0 // MajorOperatingSystemVersion
.short 0 // MinorOperatingSystemVersion
@@ -73,7 +74,7 @@ extra_header_fields:
// Everything before the kernel image is considered part of the header
.long efi_header_end - _head // SizeOfHeaders
.long 0 // CheckSum
- .short 0xa // Subsystem (EFI application)
+ .short IMAGE_SUBSYSTEM_EFI_APPLICATION // Subsystem
.short 0 // DllCharacteristics
.quad 0 // SizeOfStackReserve
.quad 0 // SizeOfStackCommit
@@ -96,10 +97,7 @@ extra_header_fields:
// Section table
section_table:
- .ascii ".text"
- .byte 0
- .byte 0
- .byte 0 // end of 0 padding of section name
+ .ascii ".text\0\0\0"
.long _end - efi_header_end // VirtualSize
.long efi_header_end - _head // VirtualAddress
.long _edata - efi_header_end // SizeOfRawData
@@ -109,7 +107,10 @@ section_table:
.long 0 // PointerToLineNumbers
.short 0 // NumberOfRelocations
.short 0 // NumberOfLineNumbers
- .long 0xe0500020 // Characteristics
+ .long IMAGE_SCN_CNT_CODE | \
+ IMAGE_SCN_MEM_EXECUTE | \
+ IMAGE_SCN_MEM_READ | \
+ IMAGE_SCN_MEM_WRITE // Characteristics
#ifdef CONFIG_DEBUG_EFI
/*
@@ -131,7 +132,7 @@ efi_debug_table:
.long 0 // TimeDateStamp
.short 0 // MajorVersion
.short 0 // MinorVersion
- .long 2 // Type == EFI_IMAGE_DEBUG_TYPE_CODEVIEW
+ .long IMAGE_DEBUG_TYPE_CODEVIEW // Type
.long efi_debug_entry_size // SizeOfData
.long 0 // RVA
.long efi_debug_entry - _head // FileOffset
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index aca9b184035a..055735ba3600 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -81,10 +81,7 @@ _head:
.quad 0 // reserved
.quad 0 // reserved
.quad 0 // reserved
- .byte 0x41 // Magic number, "ARM\x64"
- .byte 0x52
- .byte 0x4d
- .byte 0x64
+ .ascii "ARM\x64" // Magic number
__EFI_HEADER
--
2.7.4
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