From ae435cb4cc78183814f867686d278885db2988f8 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Fri, 23 Jun 2023 16:27:47 +0100 Subject: [PATCH] [efi] Process veto objects in reverse order of enumeration While not guaranteed by the UEFI specification, the enumeration of handles, protocols, and openers will generally return results in order of creation. Processing these objects in reverse order (as is already done when calling DisconnectController() on the list of all handles) will generally therefore perform the forcible uninstallation operations in reverse order of object creation, which minimises the number of implicit operations performed (e.g. when disconnecting a controller that itself still has existent child controllers). Signed-off-by: Michael Brown --- src/interface/efi/efi_veto.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/src/interface/efi/efi_veto.c b/src/interface/efi/efi_veto.c index bc19a0091..a3b60d65f 100644 --- a/src/interface/efi/efi_veto.c +++ b/src/interface/efi/efi_veto.c @@ -227,7 +227,7 @@ static int efi_veto_close_protocol ( struct efi_veto *veto, EFI_HANDLE handle, /* Close anything opened by this driver */ for ( i = 0 ; i < count ; i++ ) { - opener = &openers[i]; + opener = &openers[ count - i - 1 ]; if ( ( opener->AgentHandle != driver ) && ( opener->AgentHandle != image ) ) { continue; @@ -265,6 +265,7 @@ static int efi_veto_close_handle ( struct efi_veto *veto, EFI_HANDLE handle ) { EFI_BOOT_SERVICES *bs = efi_systab->BootServices; EFI_HANDLE driver = veto->driver; EFI_GUID **protocols; + EFI_GUID *protocol; UINTN count; unsigned int i; EFI_STATUS efirc; @@ -283,8 +284,9 @@ static int efi_veto_close_handle ( struct efi_veto *veto, EFI_HANDLE handle ) { /* Close each protocol */ for ( i = 0 ; i < count ; i++ ) { + protocol = protocols[ count - i - 1]; if ( ( rc = efi_veto_close_protocol ( veto, handle, - protocols[i] ) ) != 0 ) + protocol ) ) != 0 ) goto err_close; } @@ -307,6 +309,7 @@ static int efi_veto_close ( struct efi_veto *veto ) { EFI_BOOT_SERVICES *bs = efi_systab->BootServices; EFI_HANDLE driver = veto->driver; EFI_HANDLE *handles; + EFI_HANDLE handle; UINTN count; unsigned int i; EFI_STATUS efirc; @@ -323,7 +326,8 @@ static int efi_veto_close ( struct efi_veto *veto ) { /* Close each handle */ for ( i = 0 ; i < count ; i++ ) { - if ( ( rc = efi_veto_close_handle ( veto, handles[i] ) ) != 0 ) + handle = handles[ count - i - 1 ]; + if ( ( rc = efi_veto_close_handle ( veto, handle ) ) != 0 ) goto err_close; } @@ -628,7 +632,7 @@ void efi_veto ( void ) { struct efi_veto veto; EFI_HANDLE *drivers; EFI_HANDLE driver; - UINTN num_drivers; + UINTN count; unsigned int i; char *manufacturer; EFI_STATUS efirc; @@ -637,7 +641,7 @@ void efi_veto ( void ) { /* Locate all driver binding protocol handles */ if ( ( efirc = bs->LocateHandleBuffer ( ByProtocol, &efi_driver_binding_protocol_guid, - NULL, &num_drivers, &drivers ) ) != 0 ) { + NULL, &count, &drivers ) ) != 0 ) { rc = -EEFI ( efirc ); DBGC ( &efi_vetoes, "EFIVETO could not list all drivers: " "%s\n", strerror ( rc ) ); @@ -650,8 +654,8 @@ void efi_veto ( void ) { DBGC ( &efi_vetoes, "EFIVETO manufacturer is \"%s\"\n", manufacturer ); /* Unload any vetoed drivers */ - for ( i = 0 ; i < num_drivers ; i++ ) { - driver = drivers[i]; + for ( i = 0 ; i < count ; i++ ) { + driver = drivers[ count - i - 1 ]; if ( ( rc = efi_veto_find ( driver, manufacturer, &veto ) ) != 0 ) { DBGC ( driver, "EFIVETO %s could not determine "