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[efi] Allow elf2efi to be used for hybrid binaries 

Hybrid 32-bit BIOS and 64-bit UEFI binaries (such as wimboot) may
include R_X86_64_32 relocation records for the 32-bit BIOS portions.
These should be ignored when generating PE relocation records, since
they apply only to code that cannot be executed within the context of
the 64-bit UEFI binary, and creating a 4-byte relocation record is
invalid in a binary that may be relocated anywhere within the 64-bit
address space (see commit 907cffb "[efi] Disallow R_X86_64_32
relocations").

Add a "--hybrid" option to elf2efi, which will cause R_X86_64_32
relocation records to be silently discarded.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/963/head
Michael Brown 2023-04-05 13:29:29 +01:00
parent 1e4c3789e9
commit 9fb28080d9
1 changed files with 27 additions and 6 deletions
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33
src/util/elf2efi.c
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@ -231,7 +231,10 @@ static struct pe_header efi_pe_header = {
/** Command-line options */
struct options {
/** PE32+ subsystem type */
unsigned int subsystem;
/** Create hybrid BIOS/UEFI binary */
int hybrid;
};
/**
@ -678,10 +681,12 @@ static struct pe_section * process_section ( struct elf_file *elf,
* @v nsyms Number of symbol table entries
* @v rel Relocation record
* @v pe_reltab PE relocation table to fill in
* @v opts Options
*/
static void process_reloc ( struct elf_file *elf, const Elf_Shdr *shdr,
const Elf_Sym *syms, unsigned int nsyms,
const Elf_Rel *rel, struct pe_relocs **pe_reltab ) {
const Elf_Rel *rel, struct pe_relocs **pe_reltab,
struct options *opts ) {
unsigned int type = ELF_R_TYPE ( rel->r_info );
unsigned int sym = ELF_R_SYM ( rel->r_info );
unsigned int mrel = ELF_MREL ( elf->ehdr->e_machine, type );
@ -744,6 +749,15 @@ static void process_reloc ( struct elf_file *elf, const Elf_Shdr *shdr,
* loaded.
*/
break;
case ELF_MREL ( EM_X86_64, R_X86_64_32 ) :
/* Ignore 32-bit relocations in a hybrid
* 32-bit BIOS and 64-bit UEFI binary,
* otherwise fall through to treat as an
* unknown type.
*/
if ( opts->hybrid )
break;
/* fallthrough */
default:
eprintf ( "Unrecognised relocation type %d\n", type );
exit ( 1 );
@ -758,9 +772,11 @@ static void process_reloc ( struct elf_file *elf, const Elf_Shdr *shdr,
* @v shdr ELF section header
* @v stride Relocation record size
* @v pe_reltab PE relocation table to fill in
* @v opts Options
*/
static void process_relocs ( struct elf_file *elf, const Elf_Shdr *shdr,
size_t stride, struct pe_relocs **pe_reltab ) {
size_t stride, struct pe_relocs **pe_reltab,
struct options *opts ) {
const Elf_Shdr *symtab;
const Elf_Sym *syms;
const Elf_Rel *rel;
@ -778,7 +794,7 @@ static void process_relocs ( struct elf_file *elf, const Elf_Shdr *shdr,
rel = ( elf->data + shdr->sh_offset );
nrels = ( shdr->sh_size / stride );
for ( i = 0 ; i < nrels ; i++ ) {
process_reloc ( elf, shdr, syms, nsyms, rel, pe_reltab );
process_reloc ( elf, shdr, syms, nsyms, rel, pe_reltab, opts );
rel = ( ( ( const void * ) rel ) + stride );
}
}
@ -977,6 +993,7 @@ static void write_pe_file ( struct pe_header *pe_header,
*
* @v elf_name ELF file name
* @v pe_name PE file name
* @v opts Options
*/
static void elf2pe ( const char *elf_name, const char *pe_name,
struct options *opts ) {
@ -1020,13 +1037,13 @@ static void elf2pe ( const char *elf_name, const char *pe_name,
/* Process .rel relocations */
process_relocs ( &elf, shdr, sizeof ( Elf_Rel ),
&pe_reltab );
&pe_reltab, opts );
} else if ( shdr->sh_type == SHT_RELA ) {
/* Process .rela relocations */
process_relocs ( &elf, shdr, sizeof ( Elf_Rela ),
&pe_reltab );
&pe_reltab, opts );
}
}
@ -1079,11 +1096,12 @@ static int parse_options ( const int argc, char **argv,
int option_index = 0;
static struct option long_options[] = {
{ "subsystem", required_argument, NULL, 's' },
{ "hybrid", no_argument, NULL, 'H' },
{ "help", 0, NULL, 'h' },
{ 0, 0, 0, 0 }
};
if ( ( c = getopt_long ( argc, argv, "s:h",
if ( ( c = getopt_long ( argc, argv, "s:Hh",
long_options,
&option_index ) ) == -1 ) {
break;
@ -1098,6 +1116,9 @@ static int parse_options ( const int argc, char **argv,
exit ( 2 );
}
break;
case 'H':
opts->hybrid = 1;
break;
case 'h':
print_help ( argv[0] );
exit ( 0 );