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[efi] Separate GetMemoryMap() wrapper from shim unlocker

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2023-05-23 14:52:30 +01:00
parent 95b8338f0d
commit d2e1601cf4
1 changed files with 34 additions and 27 deletions
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61
src/interface/efi/efi_shim.c
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@@ -90,23 +90,13 @@ struct image_tag efi_shim __image_tag = {
}; };
/** Original GetMemoryMap() function */ /** Original GetMemoryMap() function */
static EFI_GET_MEMORY_MAP efi_shim_orig_map; static EFI_GET_MEMORY_MAP efi_shim_orig_get_memory_map;
/** /**
* Unlock UEFI shim * Unlock UEFI shim
* *
* @v len Memory map size
* @v map Memory map
* @v key Memory map key
* @v desclen Descriptor size
* @v descver Descriptor version
* @ret efirc EFI status code
*
*/ */
static EFIAPI EFI_STATUS efi_shim_unlock ( UINTN *len, static void efi_shim_unlock ( void ) {
EFI_MEMORY_DESCRIPTOR *map,
UINTN *key, UINTN *desclen,
UINT32 *descver ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices; EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
uint8_t empty[0]; uint8_t empty[0];
union { union {
@@ -121,9 +111,30 @@ static EFIAPI EFI_STATUS efi_shim_unlock ( UINTN *len,
u.lock->Verify ( empty, sizeof ( empty ) ); u.lock->Verify ( empty, sizeof ( empty ) );
DBGC ( &efi_shim, "SHIM unlocked via %p\n", u.lock ); DBGC ( &efi_shim, "SHIM unlocked via %p\n", u.lock );
} }
}
/**
* Wrap GetMemoryMap()
*
* @v len Memory map size
* @v map Memory map
* @v key Memory map key
* @v desclen Descriptor size
* @v descver Descriptor version
* @ret efirc EFI status code
*/
static EFIAPI EFI_STATUS efi_shim_get_memory_map ( UINTN *len,
EFI_MEMORY_DESCRIPTOR *map,
UINTN *key, UINTN *desclen,
UINT32 *descver ) {
/* Unlock shim */
if ( ! efi_shim_require_loader )
efi_shim_unlock();
/* Hand off to original GetMemoryMap() */ /* Hand off to original GetMemoryMap() */
return efi_shim_orig_map ( len, map, key, desclen, descver ); return efi_shim_orig_get_memory_map ( len, map, key, desclen,
descver );
} }
/** /**
@@ -216,27 +227,23 @@ int efi_shim_install ( struct image *shim, EFI_HANDLE handle,
EFI_BOOT_SERVICES *bs = efi_systab->BootServices; EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
int rc; int rc;
/* Intercept GetMemoryMap() via boot services table */
efi_shim_orig_map = bs->GetMemoryMap;
if ( ! efi_shim_require_loader )
bs->GetMemoryMap = efi_shim_unlock;
/* Stop PXE base code */ /* Stop PXE base code */
if ( ( ! efi_shim_allow_pxe ) && if ( ( ! efi_shim_allow_pxe ) &&
( ( rc = efi_shim_inhibit_pxe ( handle ) ) != 0 ) ) { ( ( rc = efi_shim_inhibit_pxe ( handle ) ) != 0 ) ) {
goto err_inhibit_pxe; return rc;
} }
/* Update command line */ /* Update command line */
if ( ( rc = efi_shim_cmdline ( shim, cmdline ) ) != 0 ) if ( ( rc = efi_shim_cmdline ( shim, cmdline ) ) != 0 )
goto err_cmdline; return rc;
/* Record original boot services functions */
efi_shim_orig_get_memory_map = bs->GetMemoryMap;
/* Wrap relevant boot services functions */
bs->GetMemoryMap = efi_shim_get_memory_map;
return 0; return 0;
err_cmdline:
err_inhibit_pxe:
bs->GetMemoryMap = efi_shim_orig_map;
return rc;
} }
/** /**
@@ -246,6 +253,6 @@ int efi_shim_install ( struct image *shim, EFI_HANDLE handle,
void efi_shim_uninstall ( void ) { void efi_shim_uninstall ( void ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices; EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
/* Restore original GetMemoryMap() */ /* Restore original boot services functions */
bs->GetMemoryMap = efi_shim_orig_map; bs->GetMemoryMap = efi_shim_orig_get_memory_map;
} }