efi_veto.c

Go to the documentation of this file.

/*
 * Copyright (C) 2019 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ipxe/settings.h>
#include <ipxe/pci.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/Protocol/DriverBinding.h>
#include <ipxe/efi/Protocol/LoadedImage.h>
#include <ipxe/efi/Protocol/ComponentName.h>
#include <ipxe/efi/Protocol/ComponentName2.h>
#include <ipxe/efi/efi_veto.h>

/** @file
 *
 * EFI driver vetoes
 *
 */

/** A driver veto candidate */
struct efi_veto_candidate {
        /** Veto name (for debugging) */
        const char *name;
        /**
         * Check if driver is vetoed
         *
         * @v binding           Driver binding protocol
         * @v loaded            Loaded image protocol
         * @v manufacturer      Manufacturer name, if present
         * @v name              Driver name, if present
         * @ret vetoed          Driver is to be vetoed
         */
        int ( * veto ) ( EFI_DRIVER_BINDING_PROTOCOL *binding,
                         EFI_LOADED_IMAGE_PROTOCOL *loaded,
                         const char *manufacturer, const CHAR16 *name );
};

/** A driver veto */
struct efi_veto {
        /** Driver binding handle */
        EFI_HANDLE driver;
        /** Driving binding protocol */
        EFI_DRIVER_BINDING_PROTOCOL *binding;
        /** Image handle */
        EFI_HANDLE image;
        /** Loaded image protocol */
        EFI_LOADED_IMAGE_PROTOCOL *loaded;
};

/**
 * Unload an EFI driver
 *
 * @v veto              Driver veto
 * @ret rc              Return status code
 */
static int efi_veto_unload ( struct efi_veto *veto ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE driver = veto->driver;
        EFI_HANDLE image = veto->image;
        EFI_STATUS efirc;
        int rc;

        /* Unload the driver */
        if ( ( efirc = bs->UnloadImage ( image ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( driver, "EFIVETO %s could not unload",
                       efi_handle_name ( driver ) );
                DBGC ( driver, " %s: %s\n", efi_handle_name ( image ),
                       strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Disconnect an EFI driver from all handles
 *
 * @v veto              Driver veto
 * @ret rc              Return status code
 */
static int efi_veto_disconnect ( 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;
        int rc;

        /* Enumerate all handles */
        if ( ( efirc = bs->LocateHandleBuffer ( AllHandles, NULL, NULL,
                                                &count, &handles ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( driver, "EFIVETO %s could not enumerate handles: %s\n",
                       efi_handle_name ( driver ), strerror ( rc ) );
                goto err_list;
        }

        /* Disconnect driver from all handles, in reverse order */
        for ( i = 0 ; i < count ; i++ ) {
                handle = handles[ count - i - 1 ];
                if ( ( rc = efi_disconnect ( handle, driver ) ) != 0 ) {
                        DBGC ( driver, "EFIVETO %s could not disconnect",
                               efi_handle_name ( driver ) );
                        DBGC ( driver, " %s: %s\n",
                               efi_handle_name ( handle ), strerror ( rc ) );
                        goto err_disconnect;
                }
        }

        /* Success */
        rc = 0;
        DBGC2 ( driver, "EFIVETO %s disconnected all handles\n",
                efi_handle_name ( driver ) );

 err_disconnect:
        bs->FreePool ( handles );
 err_list:
        return rc;
}

/**
 * Uninstall an EFI driver binding protocol
 *
 * @v veto              Driver veto
 * @ret rc              Return status code
 */
static int efi_veto_uninstall ( struct efi_veto *veto ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE driver = veto->driver;
        EFI_DRIVER_BINDING_PROTOCOL *binding;
        EFI_STATUS efirc;
        int rc;

        /* Open driver binding protocol */
        if ( ( rc = efi_open ( driver, &efi_driver_binding_protocol_guid,
                               &binding ) ) != 0 ) {
                DBGC ( driver, "EFIVETO %s could not open driver binding "
                       "protocol: %s\n", efi_handle_name ( driver ),
                       strerror ( rc ) );
                return rc;
        }

        /* Uninstall driver binding protocol */
        if ( ( efirc = bs->UninstallMultipleProtocolInterfaces (
                        driver, &efi_driver_binding_protocol_guid,
                        binding, NULL ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( driver, "EFIVETO %s could not uninstall driver "
                       "binding protocol: %s\n",
                       efi_handle_name ( driver ), strerror ( rc ) );
                return rc;
        }

        DBGC2 ( driver, "EFIVETO %s uninstalled driver binding protocol\n",
                efi_handle_name ( driver ) );
        return 0;
}

/**
 * Close protocol on handle potentially opened by an EFI driver
 *
 * @v veto              Driver veto
 * @v handle            Potentially opened handle
 * @v protocol          Opened protocol
 * @ret rc              Return status code
 */
static int efi_veto_close_protocol ( struct efi_veto *veto, EFI_HANDLE handle,
                                     EFI_GUID *protocol ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE driver = veto->driver;
        EFI_HANDLE image = veto->image;
        EFI_OPEN_PROTOCOL_INFORMATION_ENTRY *openers;
        EFI_OPEN_PROTOCOL_INFORMATION_ENTRY *opener;
        EFI_HANDLE controller;
        UINTN count;
        unsigned int i;
        EFI_STATUS efirc;
        int rc;

        /* Retrieve list of openers */
        if ( ( efirc = bs->OpenProtocolInformation ( handle, protocol, &openers,
                                                     &count ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( driver, "EFIVETO %s could not retrieve openers",
                       efi_handle_name ( driver ) );
                DBGC ( driver, " of %s %s: %s", efi_handle_name ( handle ),
                       efi_guid_ntoa ( protocol ), strerror ( rc ) );
                goto err_list;
        }

        /* Close anything opened by this driver */
        for ( i = 0 ; i < count ; i++ ) {
                opener = &openers[ count - i - 1 ];
                if ( ( opener->AgentHandle != driver ) &&
                     ( opener->AgentHandle != image ) ) {
                        continue;
                }
                controller = opener->ControllerHandle;
                DBGC_EFI_OPENER ( driver, handle, protocol, opener );
                if ( ( efirc = bs->CloseProtocol ( handle, protocol, driver,
                                                   controller ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        DBGC ( driver, "EFIVETO %s could not close stray open",
                               efi_handle_name ( driver ) );
                        DBGC ( driver, " of %s: %s\n",
                               efi_handle_name ( handle ), strerror ( rc ) );
                        goto err_close;
                }
        }

        /* Success */
        rc = 0;

 err_close:
        bs->FreePool ( openers );
 err_list:
        return rc;
}

/**
 * Close handle potentially opened by an EFI driver
 *
 * @v veto              Driver veto
 * @v handle            Potentially opened handle
 * @ret rc              Return status code
 */
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;
        int rc;

        /* Retrieve list of protocols */
        if ( ( efirc = bs->ProtocolsPerHandle ( handle, &protocols,
                                                &count ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( driver, "EFIVETO %s could not retrieve protocols",
                       efi_handle_name ( driver ) );
                DBGC ( driver, " for %s: %s\n",
                       efi_handle_name ( handle ), strerror ( rc ) );
                goto err_list;
        }

        /* Close each protocol */
        for ( i = 0 ; i < count ; i++ ) {
                protocol = protocols[ count - i - 1];
                if ( ( rc = efi_veto_close_protocol ( veto, handle,
                                                      protocol ) ) != 0 )
                        goto err_close;
        }

        /* Success */
        rc = 0;

 err_close:
        bs->FreePool ( protocols );
 err_list:
        return rc;
}

/**
 * Close all remaining handles opened by an EFI driver
 *
 * @v veto              Driver veto
 * @ret rc              Return status code
 */
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;
        int rc;

        /* Enumerate all handles */
        if ( ( efirc = bs->LocateHandleBuffer ( AllHandles, NULL, NULL,
                                                &count, &handles ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( driver, "EFIVETO %s could not enumerate handles: %s\n",
                       efi_handle_name ( driver ), strerror ( rc ) );
                goto err_list;
        }

        /* Close each handle */
        for ( i = 0 ; i < count ; i++ ) {
                handle = handles[ count - i - 1 ];
                if ( ( rc = efi_veto_close_handle ( veto, handle ) ) != 0 )
                        goto err_close;
        }

        /* Success */
        rc = 0;
        DBGC2 ( driver, "EFIVETO %s closed all remaining handles\n",
                efi_handle_name ( driver ) );

 err_close:
        bs->FreePool ( handles );
 err_list:
        return rc;
}

/**
 * Terminate an EFI driver with extreme prejudice
 *
 * @v veto              Driver veto
 * @ret rc              Return status code
 */
static int efi_veto_destroy ( struct efi_veto *veto ) {
        EFI_HANDLE driver = veto->driver;
        int rc;

        /* Disconnect driver from all handles */
        if ( ( rc = efi_veto_disconnect ( veto ) ) != 0 )
                return rc;

        /* Uninstall driver binding protocol */
        if ( ( rc = efi_veto_uninstall ( veto ) ) != 0 )
                return rc;

        /* Close any remaining opened handles */
        if ( ( rc = efi_veto_close ( veto ) ) != 0 )
                return rc;

        DBGC ( driver, "EFIVETO %s forcibly removed\n",
               efi_handle_name ( driver ) );
        return 0;
}

/**
 * Veto an EFI driver
 *
 * @v veto              Driver veto
 * @ret rc              Return status code
 */
static int efi_veto_driver ( struct efi_veto *veto ) {
        int rc;

        /* Try gracefully unloading the driver */
        if ( ( rc = efi_veto_unload ( veto ) ) == 0 )
                return 0;

        /* If that fails, use a hammer */
        if ( ( rc = efi_veto_destroy ( veto ) ) == 0 )
                return 0;

        return rc;
}

/**
 * Veto Ip4ConfigDxe driver on some platforms
 *
 * @v binding           Driver binding protocol
 * @v loaded            Loaded image protocol
 * @v manufacturer      Manufacturer name, if present
 * @v name              Driver name, if present
 * @ret vetoed          Driver is to be vetoed
 */
static int
efi_veto_ip4config ( EFI_DRIVER_BINDING_PROTOCOL *binding __unused,
                     EFI_LOADED_IMAGE_PROTOCOL *loaded __unused,
                     const char *manufacturer, const CHAR16 *name ) {
        static const CHAR16 ip4cfg[] = L"IP4 CONFIG Network Service Driver";
        static const char *dell = "Dell Inc.";
        static const char *itautec = "Itautec S.A.";

        /* Check manufacturer and driver name */
        if ( ! manufacturer )
                return 0;
        if ( ! name )
                return 0;
        if ( ( strcmp ( manufacturer, dell ) != 0 ) &&
             ( strcmp ( manufacturer, itautec ) != 0 ) )
                return 0;
        if ( memcmp ( name, ip4cfg, sizeof ( ip4cfg ) ) != 0 )
                return 0;

        return 1;
}

/**
 * Veto HP XhciDxe driver
 *
 * @v binding           Driver binding protocol
 * @v loaded            Loaded image protocol
 * @v manufacturer      Manufacturer name, if present
 * @v name              Driver name, if present
 * @ret vetoed          Driver is to be vetoed
 */
static int
efi_veto_hp_xhci ( EFI_DRIVER_BINDING_PROTOCOL *binding __unused,
                   EFI_LOADED_IMAGE_PROTOCOL *loaded __unused,
                   const char *manufacturer, const CHAR16 *name ) {
        static const CHAR16 xhci[] = L"Usb Xhci Driver";
        static const char *hp = "HP";
        struct pci_driver *driver;

        /* Check manufacturer and driver name */
        if ( ! manufacturer )
                return 0;
        if ( ! name )
                return 0;
        if ( strcmp ( manufacturer, hp ) != 0 )
                return 0;
        if ( memcmp ( name, xhci, sizeof ( xhci ) ) != 0 )
                return 0;

        /* Veto driver only if we have our own xHCI driver */
        for_each_table_entry ( driver, PCI_DRIVERS ) {
                if ( driver->class.class ==
                     PCI_CLASS ( PCI_CLASS_SERIAL, PCI_CLASS_SERIAL_USB,
                                 PCI_CLASS_SERIAL_USB_XHCI ) ) {
                        return 1;
                }
        }

        return 0;
}

/**
 * Veto VMware UefiPxeBcDxe driver
 *
 * @v binding           Driver binding protocol
 * @v loaded            Loaded image protocol
 * @v manufacturer      Manufacturer name, if present
 * @v name              Driver name, if present
 * @ret vetoed          Driver is to be vetoed
 */
static int
efi_veto_vmware_uefipxebc ( EFI_DRIVER_BINDING_PROTOCOL *binding __unused,
                            EFI_LOADED_IMAGE_PROTOCOL *loaded __unused,
                            const char *manufacturer, const CHAR16 *name ) {
        static const CHAR16 uefipxebc[] = L"UEFI PXE Base Code Driver";
        static const char *vmware = "VMware, Inc.";

        /* Check manufacturer and driver name */
        if ( ! manufacturer )
                return 0;
        if ( ! name )
                return 0;
        if ( strcmp ( manufacturer, vmware ) != 0 )
                return 0;
        if ( memcmp ( name, uefipxebc, sizeof ( uefipxebc ) ) != 0 )
                return 0;

        return 1;
}

/**
 * Veto Dhcp6Dxe driver
 *
 * @v binding           Driver binding protocol
 * @v loaded            Loaded image protocol
 * @v manufacturer      Manufacturer name, if present
 * @v name              Driver name, if present
 * @ret vetoed          Driver is to be vetoed
 */
static int efi_veto_dhcp6 ( EFI_DRIVER_BINDING_PROTOCOL *binding __unused,
                            EFI_LOADED_IMAGE_PROTOCOL *loaded __unused,
                            const char *manufacturer __unused,
                            const CHAR16 *name ) {
        static const CHAR16 dhcp6[] = L"DHCP6 Protocol Driver";

        /* Check driver name */
        if ( ! name )
                return 0;
        if ( memcmp ( name, dhcp6, sizeof ( dhcp6 ) ) != 0 )
                return 0;

        return 1;
}

/** Driver vetoes */
static struct efi_veto_candidate efi_vetoes[] = {
        {
                .name = "Ip4Config",
                .veto = efi_veto_ip4config,
        },
        {
                .name = "HP Xhci",
                .veto = efi_veto_hp_xhci,
        },
        {
                .name = "VMware UefiPxeBc",
                .veto = efi_veto_vmware_uefipxebc,
        },
        {
                .name = "Dhcp6",
                .veto = efi_veto_dhcp6,
        },
};

/**
 * Find driver veto, if any
 *
 * @v driver            Driver binding handle
 * @v manufacturer      Manufacturer name, if present
 * @ret veto            Driver veto to fill in
 * @ret rc              Return status code
 */
static int efi_veto_find ( EFI_HANDLE driver, const char *manufacturer,
                           struct efi_veto *veto ) {
        EFI_DRIVER_BINDING_PROTOCOL *binding;
        EFI_LOADED_IMAGE_PROTOCOL *loaded;
        EFI_COMPONENT_NAME2_PROTOCOL *wtf2;
        EFI_COMPONENT_NAME_PROTOCOL *wtf;
        CHAR16 *name;
        unsigned int i;
        EFI_HANDLE image;
        EFI_STATUS efirc;
        int rc;

        /* Mark as not vetoed */
        memset ( veto, 0, sizeof ( *veto ) );

        /* Open driver binding protocol */
        if ( ( rc = efi_open ( driver, &efi_driver_binding_protocol_guid,
                               &binding ) ) != 0 ) {
                DBGC ( driver, "EFIVETO %s could not open driver binding "
                       "protocol: %s\n", efi_handle_name ( driver ),
                       strerror ( rc ) );
                return rc;
        }
        image = binding->ImageHandle;

        /* Open loaded image protocol */
        if ( ( rc = efi_open ( image, &efi_loaded_image_protocol_guid,
                               &loaded ) ) != 0 ) {
                DBGC ( driver, "EFIVETO %s could not open",
                       efi_handle_name ( driver ) );
                DBGC ( driver, " %s loaded image protocol: %s\n",
                       efi_handle_name ( image ), strerror ( rc ) );
                return rc;
        }

        /* Open component name protocol, if present */
        if ( ( rc = efi_open ( image, &efi_component_name2_protocol_guid,
                               &wtf2 ) ) != 0 ) {
                /* Ignore failure; is not required to be present */
        }

        /* Open obsolete component name protocol, if present */
        if ( ( rc = efi_open ( image, &efi_component_name_protocol_guid,
                               &wtf ) ) != 0 ) {
                /* Ignore failure; is not required to be present */
        }

        /* Get driver name, if available */
        if ( ( wtf2 && ( ( efirc = wtf2->GetDriverName ( wtf2, "en",
                                                         &name ) == 0 ) ) ) ||
             ( wtf && ( ( efirc = wtf->GetDriverName ( wtf, "eng",
                                                       &name ) == 0 ) ) ) ) {
                /* Driver has a name */
        } else {
                /* Ignore failure; name is not required to be present */
                name = NULL;
        }

        /* Check vetoes */
        DBGC2 ( &efi_vetoes, "EFIVETO checking %s [%p,%p)\n",
                efi_handle_name ( driver ), loaded->ImageBase,
                ( loaded->ImageBase + loaded->ImageSize ) );
        for ( i = 0 ; i < ( sizeof ( efi_vetoes ) /
                            sizeof ( efi_vetoes[0] ) ) ; i++ ) {
                if ( efi_vetoes[i].veto ( binding, loaded, manufacturer,
                                          name ) ) {
                        DBGC ( driver, "EFIVETO %s is vetoed (%s)\n",
                               efi_handle_name ( driver ),
                               efi_vetoes[i].name );
                        veto->driver = driver;
                        veto->binding = binding;
                        veto->image = image;
                        veto->loaded = loaded;
                        break;
                }
        }

        return 0;
}

/**
 * Remove any vetoed drivers
 *
 */
void efi_veto ( void ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct efi_veto veto;
        EFI_HANDLE *drivers;
        EFI_HANDLE driver;
        UINTN count;
        unsigned int i;
        char *manufacturer;
        EFI_STATUS efirc;
        int rc;

        /* Locate all driver binding protocol handles */
        if ( ( efirc = bs->LocateHandleBuffer (
                        ByProtocol, &efi_driver_binding_protocol_guid,
                        NULL, &count, &drivers ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( &efi_vetoes, "EFIVETO could not list all drivers: "
                       "%s\n", strerror ( rc ) );
                return;
        }

        /* Get manufacturer name */
        fetch_string_setting_copy ( NULL, &manufacturer_setting,
                                    &manufacturer );
        DBGC ( &efi_vetoes, "EFIVETO manufacturer is \"%s\"\n", manufacturer );

        /* Unload any vetoed drivers */
        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 "
                               "vetoing: %s\n",
                               efi_handle_name ( driver ), strerror ( rc ) );
                        continue;
                }
                if ( ! veto.driver )
                        continue;
                if ( ( rc = efi_veto_driver ( &veto ) ) != 0 ) {
                        DBGC ( driver, "EFIVETO %s could not veto: %s\n",
                               efi_handle_name ( driver ), strerror ( rc ) );
                }
        }

        /* Free manufacturer name */
        free ( manufacturer );

        /* Free handle list */
        bs->FreePool ( drivers );
}