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[efi] Align EFI image sections by page size

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For optimal memory permission management, PE sections need to be
aligned by the platform's minimum page size.  Currently, the PE
section alignment is fixed to 32 bytes, which is below the typical 4kB
page size.  Align all sections to 4kB and adjust ELF to PE image
conversion accordingly.

Signed-off-by: Marvin Häuser <mhaeuser@posteo.de>
This commit is contained in:
Marvin Häuser
2021-04-08 20:04:16 +02:00
committed by Michael Brown
parent 1cc8756511
commit f1e9e2b062
2 changed files with 33 additions and 20 deletions
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35
src/util/elf2efi.c
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@@ -125,7 +125,8 @@
#define R_ARM_V4BX 40
#endif
#define EFI_FILE_ALIGN 0x20
#define EFI_FILE_ALIGN 0x20
#define EFI_IMAGE_ALIGN 0x1000
struct elf_file {
void *data;
@@ -173,9 +174,9 @@ static struct pe_header efi_pe_header = {
.Magic = EFI_IMAGE_NT_OPTIONAL_HDR_MAGIC,
.MajorLinkerVersion = 42,
.MinorLinkerVersion = 42,
.SectionAlignment = EFI_FILE_ALIGN,
.SectionAlignment = EFI_IMAGE_ALIGN,
.FileAlignment = EFI_FILE_ALIGN,
.SizeOfImage = sizeof ( efi_pe_header ),
.SizeOfImage = EFI_IMAGE_ALIGN,
.SizeOfHeaders = sizeof ( efi_pe_header ),
.NumberOfRvaAndSizes =
EFI_IMAGE_NUMBER_OF_DIRECTORY_ENTRIES,
@@ -216,6 +217,16 @@ static unsigned long efi_file_align ( unsigned long offset ) {
return ( ( offset + EFI_FILE_ALIGN - 1 ) & ~( EFI_FILE_ALIGN - 1 ) );
}
/**
* Align section within PE image
*
* @v offset Unaligned offset
* @ret aligned_offset Aligned offset
*/
static unsigned long efi_image_align ( unsigned long offset ) {
return ( ( offset + EFI_IMAGE_ALIGN - 1 ) & ~( EFI_IMAGE_ALIGN - 1 ) );
}
/**
* Generate entry in PE relocation table
*
@@ -605,7 +616,7 @@ static struct pe_section * process_section ( struct elf_file *elf,
pe_header->nt.FileHeader.NumberOfSections++;
pe_header->nt.OptionalHeader.SizeOfHeaders += sizeof ( new->hdr );
pe_header->nt.OptionalHeader.SizeOfImage =
efi_file_align ( data_end );
efi_image_align ( data_end );
return new;
}
@@ -728,13 +739,15 @@ static struct pe_section *
create_reloc_section ( struct pe_header *pe_header,
struct pe_relocs *pe_reltab ) {
struct pe_section *reloc;
size_t section_rawsz;
size_t section_memsz;
size_t section_filesz;
EFI_IMAGE_DATA_DIRECTORY *relocdir;
/* Allocate PE section */
section_memsz = output_pe_reltab ( pe_reltab, NULL );
section_filesz = efi_file_align ( section_memsz );
section_rawsz = output_pe_reltab ( pe_reltab, NULL );
section_filesz = efi_file_align ( section_rawsz );
section_memsz = efi_image_align ( section_rawsz );
reloc = xmalloc ( sizeof ( *reloc ) + section_filesz );
memset ( reloc, 0, sizeof ( *reloc ) + section_filesz );
@@ -754,11 +767,11 @@ create_reloc_section ( struct pe_header *pe_header,
/* Update file header details */
pe_header->nt.FileHeader.NumberOfSections++;
pe_header->nt.OptionalHeader.SizeOfHeaders += sizeof ( reloc->hdr );
pe_header->nt.OptionalHeader.SizeOfImage += section_filesz;
pe_header->nt.OptionalHeader.SizeOfImage += section_memsz;
relocdir = &(pe_header->nt.OptionalHeader.DataDirectory
[EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC]);
relocdir->VirtualAddress = reloc->hdr.VirtualAddress;
relocdir->Size = reloc->hdr.Misc.VirtualSize;
relocdir->Size = section_rawsz;
return reloc;
}
@@ -796,8 +809,8 @@ create_debug_section ( struct pe_header *pe_header, const char *filename ) {
} *contents;
/* Allocate PE section */
section_memsz = sizeof ( *contents );
section_filesz = efi_file_align ( section_memsz );
section_memsz = efi_image_align ( sizeof ( *contents ) );
section_filesz = efi_file_align ( sizeof ( *contents ) );
debug = xmalloc ( sizeof ( *debug ) + section_filesz );
memset ( debug, 0, sizeof ( *debug ) + section_filesz );
contents = ( void * ) debug->contents;
@@ -828,7 +841,7 @@ create_debug_section ( struct pe_header *pe_header, const char *filename ) {
/* Update file header details */
pe_header->nt.FileHeader.NumberOfSections++;
pe_header->nt.OptionalHeader.SizeOfHeaders += sizeof ( debug->hdr );
pe_header->nt.OptionalHeader.SizeOfImage += section_filesz;
pe_header->nt.OptionalHeader.SizeOfImage += section_memsz;
debugdir = &(pe_header->nt.OptionalHeader.DataDirectory
[EFI_IMAGE_DIRECTORY_ENTRY_DEBUG]);
debugdir->VirtualAddress = debug->hdr.VirtualAddress;