src/boot/efi/stub.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /* This program is free software; you can redistribute it and/or modify it
   3  * under the terms of the GNU Lesser General Public License as published by
   4  * the Free Software Foundation; either version 2.1 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful, but
   8  * WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10  * Lesser General Public License for more details.
  11  *
  12  * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
  13  */
  14
  15 #include <efi.h>
  16 #include <efilib.h>
  17
  18 #include "disk.h"
  19 #include "graphics.h"
  20 #include "linux.h"
  21 #include "measure.h"
  22 #include "pe.h"
  23 #include "splash.h"
  24 #include "util.h"
  25
  26 /* magic string to find in the binary image */
  27 static const char __attribute__((used)) magic[] = "#### LoaderInfo: systemd-stub " PACKAGE_VERSION " ####";
  28
  29 static const EFI_GUID global_guid = EFI_GLOBAL_VARIABLE;
  30
  31 EFI_STATUS efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *sys_table) {
  32         EFI_LOADED_IMAGE *loaded_image;
  33         CHAR8 *b;
  34         UINTN size;
  35         BOOLEAN secure = FALSE;
  36         CHAR8 *sections[] = {
  37                 (UINT8 *)".cmdline",
  38                 (UINT8 *)".linux",
  39                 (UINT8 *)".initrd",
  40                 (UINT8 *)".splash",
  41                 NULL
  42         };
  43         UINTN addrs[ELEMENTSOF(sections)-1] = {};
  44         UINTN offs[ELEMENTSOF(sections)-1] = {};
  45         UINTN szs[ELEMENTSOF(sections)-1] = {};
  46         CHAR8 *cmdline = NULL;
  47         UINTN cmdline_len;
  48         CHAR16 uuid[37];
  49         EFI_STATUS err;
  50
  51         InitializeLib(image, sys_table);
  52
  53         err = uefi_call_wrapper(BS->OpenProtocol, 6, image, &LoadedImageProtocol, (VOID **)&loaded_image,
  54                                 image, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
  55         if (EFI_ERROR(err)) {
  56                 Print(L"Error getting a LoadedImageProtocol handle: %r ", err);
  57                 uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
  58                 return err;
  59         }
  60
  61         if (efivar_get_raw(&global_guid, L"SecureBoot", &b, &size) == EFI_SUCCESS) {
  62                 if (*b > 0)
  63                         secure = TRUE;
  64                 FreePool(b);
  65         }
  66         err = pe_memory_locate_sections(loaded_image->ImageBase, sections, addrs, offs, szs);
  67         if (EFI_ERROR(err)) {
  68                 Print(L"Unable to locate embedded .linux section: %r ", err);
  69                 uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
  70                 return err;
  71         }
  72
  73         if (szs[0] > 0)
  74                 cmdline = (CHAR8 *)(loaded_image->ImageBase + addrs[0]);
  75
  76         cmdline_len = szs[0];
  77
  78         /* if we are not in secure boot mode, accept a custom command line and replace the built-in one */
  79         if (!secure && loaded_image->LoadOptionsSize > 0 && *(CHAR16 *)loaded_image->LoadOptions != 0) {
  80                 CHAR16 *options;
  81                 CHAR8 *line;
  82                 UINTN i;
  83
  84                 options = (CHAR16 *)loaded_image->LoadOptions;
  85                 cmdline_len = (loaded_image->LoadOptionsSize / sizeof(CHAR16)) * sizeof(CHAR8);
  86                 line = AllocatePool(cmdline_len);
  87                 for (i = 0; i < cmdline_len; i++)
  88                         line[i] = options[i];
  89                 cmdline = line;
  90
  91 #if ENABLE_TPM
  92                 /* Try to log any options to the TPM, especially manually edited options */
  93                 err = tpm_log_event(SD_TPM_PCR,
  94                                     (EFI_PHYSICAL_ADDRESS) loaded_image->LoadOptions,
  95                                     loaded_image->LoadOptionsSize, loaded_image->LoadOptions);
  96                 if (EFI_ERROR(err)) {
  97                         Print(L"Unable to add image options measurement: %r", err);
  98                         uefi_call_wrapper(BS->Stall, 1, 200 * 1000);
  99                 }
 100 #endif
 101         }
 102
 103         /* export the device path this image is started from */
 104         if (disk_get_part_uuid(loaded_image->DeviceHandle, uuid) == EFI_SUCCESS)
 105                 efivar_set(L"LoaderDevicePartUUID", uuid, FALSE);
 106
 107         /* if LoaderImageIdentifier is not set, assume the image with this stub was loaded directly from UEFI */
 108         if (efivar_get_raw(&global_guid, L"LoaderImageIdentifier", &b, &size) != EFI_SUCCESS) {
 109                 CHAR16 *loaded_image_path = DevicePathToStr(loaded_image->FilePath);
 110                 efivar_set(L"LoaderImageIdentifier", loaded_image_path, FALSE);
 111                 FreePool(loaded_image_path);
 112         }
 113
 114         /* if LoaderFirmwareInfo is not set, let's set it */
 115         if (efivar_get_raw(&global_guid, L"LoaderFirmwareInfo", &b, &size) != EFI_SUCCESS) {
 116                 CHAR16 *loader_firmware_info = PoolPrint(L"%s %d.%02d", ST->FirmwareVendor, ST->FirmwareRevision >> 16, ST->FirmwareRevision & 0xffff);
 117                 efivar_set(L"LoaderFirmwareInfo", loader_firmware_info, FALSE);
 118                 FreePool(loader_firmware_info);
 119         }
 120         /* ditto for LoaderFirmwareType */
 121         if (efivar_get_raw(&global_guid, L"LoaderFirmwareType", &b, &size) != EFI_SUCCESS) {
 122                 CHAR16 *loader_firmware_type = PoolPrint(L"UEFI %d.%02d", ST->Hdr.Revision >> 16, ST->Hdr.Revision & 0xffff);
 123                 efivar_set(L"LoaderFirmwareType", loader_firmware_type, FALSE);
 124                 FreePool(loader_firmware_type);
 125         }
 126
 127
 128         if (szs[3] > 0)
 129                 graphics_splash((UINT8 *)((UINTN)loaded_image->ImageBase + addrs[3]), szs[3], NULL);
 130
 131         err = linux_exec(image, cmdline, cmdline_len,
 132                          (UINTN)loaded_image->ImageBase + addrs[1],
 133                          (UINTN)loaded_image->ImageBase + addrs[2], szs[2], secure);
 134
 135         graphics_mode(FALSE);
 136         Print(L"Execution of embedded linux image failed: %r\n", err);
 137         uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
 138         return err;
 139 }