src/boot/efi/stub.c

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