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[efi] Do not assume canonical PE section ordering 

The BaseOfCode (and, in PE32, BaseOfData) fields imply an assumption
that binaries are laid out as code followed by initialised data
followed by uninitialised data.  This assumption may not be valid for
complex binaries such as wimboot.

Remove this implicit assumption, and use arguably justifiable values
for the assorted summary start and size fields within the PE headers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/1082/head
Michael Brown 2023-11-24 15:55:41 +00:00
parent 18582a05fc
commit 03ff1bb99a
1 changed files with 37 additions and 56 deletions
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93
src/util/elf2efi.c
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@ -602,31 +602,29 @@ static struct pe_section * process_section ( struct elf_file *elf,
size_t name_len;
size_t section_memsz;
size_t section_filesz;
unsigned long code_start;
unsigned long code_end;
unsigned long data_start;
unsigned long data_mid;
unsigned long data_end;
unsigned long start;
unsigned long end;
unsigned long *applicable_start;
unsigned long *applicable_end;
uint32_t start;
uint32_t end;
uint32_t *code_start;
uint32_t *data_start;
uint32_t *code_size;
uint32_t *data_size;
uint32_t *bss_size;
uint32_t *applicable_start;
uint32_t *applicable_size;
/* Get section name */
name = elf_string ( elf, elf->ehdr->e_shstrndx, shdr->sh_name );
/* Extract current RVA limits from file header */
code_start = pe_header->nt.OptionalHeader.BaseOfCode;
code_end = ( code_start + pe_header->nt.OptionalHeader.SizeOfCode );
/* Identify start and size limit fields from file header */
code_start = &pe_header->nt.OptionalHeader.BaseOfCode;
code_size = &pe_header->nt.OptionalHeader.SizeOfCode;
#if defined(EFI_TARGET32)
data_start = pe_header->nt.OptionalHeader.BaseOfData;
data_start = &pe_header->nt.OptionalHeader.BaseOfData;
#elif defined(EFI_TARGET64)
data_start = code_end;
data_start = NULL;
#endif
data_mid = ( data_start +
pe_header->nt.OptionalHeader.SizeOfInitializedData );
data_end = ( data_mid +
pe_header->nt.OptionalHeader.SizeOfUninitializedData );
data_size = &pe_header->nt.OptionalHeader.SizeOfInitializedData;
bss_size = &pe_header->nt.OptionalHeader.SizeOfUninitializedData;
/* Allocate PE section */
section_memsz = shdr->sh_size;
@ -659,7 +657,7 @@ static struct pe_section * process_section ( struct elf_file *elf,
new->hidden = 1;
}
/* Fill in section characteristics and update RVA limits */
/* Fill in section characteristics and identify applicable limits */
if ( ( shdr->sh_type == SHT_PROGBITS ) &&
( shdr->sh_flags & SHF_WRITE ) ) {
/* .data-type section */
@ -668,8 +666,8 @@ static struct pe_section * process_section ( struct elf_file *elf,
EFI_IMAGE_SCN_MEM_NOT_PAGED |
EFI_IMAGE_SCN_MEM_READ |
EFI_IMAGE_SCN_MEM_WRITE );
applicable_start = &data_start;
applicable_end = &data_mid;
applicable_start = data_start;
applicable_size = data_size;
} else if ( ( shdr->sh_type == SHT_PROGBITS ) &&
( shdr->sh_flags & SHF_EXECINSTR ) ) {
/* .text-type section */
@ -678,16 +676,16 @@ static struct pe_section * process_section ( struct elf_file *elf,
EFI_IMAGE_SCN_MEM_NOT_PAGED |
EFI_IMAGE_SCN_MEM_EXECUTE |
EFI_IMAGE_SCN_MEM_READ );
applicable_start = &code_start;
applicable_end = &code_end;
applicable_start = code_start;
applicable_size = code_size;
} else if ( shdr->sh_type == SHT_PROGBITS ) {
/* .rodata-type section */
new->hdr.Characteristics =
( EFI_IMAGE_SCN_CNT_INITIALIZED_DATA |
EFI_IMAGE_SCN_MEM_NOT_PAGED |
EFI_IMAGE_SCN_MEM_READ );
applicable_start = &data_start;
applicable_end = &data_mid;
applicable_start = data_start;
applicable_size = data_size;
} else if ( shdr->sh_type == SHT_NOBITS ) {
/* .bss-type section */
new->hdr.Characteristics =
@ -695,8 +693,8 @@ static struct pe_section * process_section ( struct elf_file *elf,
EFI_IMAGE_SCN_MEM_NOT_PAGED |
EFI_IMAGE_SCN_MEM_READ |
EFI_IMAGE_SCN_MEM_WRITE );
applicable_start = &data_mid;
applicable_end = &data_end;
applicable_start = data_start;
applicable_size = bss_size;
} else {
eprintf ( "Unrecognised characteristics for section %s\n",
name );
@ -709,41 +707,24 @@ static struct pe_section * process_section ( struct elf_file *elf,
shdr->sh_size );
}
/* Update RVA limits */
/* Update file header fields */
start = new->hdr.VirtualAddress;
end = ( start + new->hdr.Misc.VirtualSize );
if ( ! new->hidden ) {
if ( ( ! *applicable_start ) || ( *applicable_start >= start ) )
*applicable_start = start;
if ( *applicable_end < end )
*applicable_end = end;
}
if ( data_start < code_end )
data_start = code_end;
if ( data_mid < data_start )
data_mid = data_start;
if ( data_end < data_mid )
data_end = data_mid;
/* Write RVA limits back to file header */
pe_header->nt.OptionalHeader.BaseOfCode = code_start;
pe_header->nt.OptionalHeader.SizeOfCode = ( code_end - code_start );
#if defined(EFI_TARGET32)
pe_header->nt.OptionalHeader.BaseOfData = data_start;
#endif
pe_header->nt.OptionalHeader.SizeOfInitializedData =
( data_mid - data_start );
pe_header->nt.OptionalHeader.SizeOfUninitializedData =
( data_end - data_mid );
/* Update remaining file header fields */
if ( ! new->hidden ) {
pe_header->nt.FileHeader.NumberOfSections++;
pe_header->nt.OptionalHeader.SizeOfHeaders +=
sizeof ( new->hdr );
if ( applicable_start && ( ( *applicable_start == 0 ) ||
( start < *applicable_start ) ) ) {
*applicable_start = start;
}
if ( applicable_size ) {
*applicable_size += section_memsz;
}
}
end = efi_image_align ( start + section_memsz );
if ( end > pe_header->nt.OptionalHeader.SizeOfImage ) {
pe_header->nt.OptionalHeader.SizeOfImage = end;
}
pe_header->nt.OptionalHeader.SizeOfImage =
efi_image_align ( data_end );
return new;
}