e5ee3e8fa5
Read the verity hash from the kernel binary and pass it to the running system via the kernel command line
378 lines
9.3 KiB
C
378 lines
9.3 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2012 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/loader.h>
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#include <grub/file.h>
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#include <grub/err.h>
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#include <grub/types.h>
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#include <grub/mm.h>
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#include <grub/cpu/linux.h>
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#include <grub/command.h>
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#include <grub/i18n.h>
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#include <grub/lib/cmdline.h>
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#include <grub/efi/efi.h>
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#include "../verity-hash.h"
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GRUB_MOD_LICENSE ("GPLv3+");
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static grub_dl_t my_mod;
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static int loaded;
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static void *kernel_mem;
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static grub_uint64_t kernel_size;
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static grub_uint8_t *initrd_mem;
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static grub_uint32_t handover_offset;
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struct linux_kernel_params *params;
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static char *linux_cmdline;
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#define BYTES_TO_PAGES(bytes) (((bytes) + 0xfff) >> 12)
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#define SHIM_LOCK_GUID \
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{ 0x605dab50, 0xe046, 0x4300, {0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23} }
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struct grub_efi_shim_lock
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{
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grub_efi_status_t (*verify) (void *buffer, grub_uint32_t size);
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};
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typedef struct grub_efi_shim_lock grub_efi_shim_lock_t;
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static grub_efi_boolean_t
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grub_linuxefi_secure_validate (void *data, grub_uint32_t size)
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{
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grub_efi_guid_t guid = SHIM_LOCK_GUID;
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grub_efi_shim_lock_t *shim_lock;
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shim_lock = grub_efi_locate_protocol(&guid, NULL);
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if (!shim_lock) {
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if (grub_efi_secure_boot())
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return 0;
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else
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return 1;
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}
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if (shim_lock->verify(data, size) == GRUB_EFI_SUCCESS)
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return 1;
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return 0;
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}
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typedef void(*handover_func)(void *, grub_efi_system_table_t *, struct linux_kernel_params *);
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static grub_err_t
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grub_linuxefi_boot (void)
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{
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handover_func hf;
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int offset = 0;
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#ifdef __x86_64__
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offset = 512;
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#endif
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hf = (handover_func)((char *)kernel_mem + handover_offset + offset);
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asm volatile ("cli");
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hf (grub_efi_image_handle, grub_efi_system_table, params);
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/* Not reached */
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return GRUB_ERR_NONE;
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}
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static grub_err_t
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grub_linuxefi_unload (void)
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{
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grub_dl_unref (my_mod);
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loaded = 0;
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if (initrd_mem)
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grub_efi_free_pages((grub_efi_physical_address_t)initrd_mem, BYTES_TO_PAGES(params->ramdisk_size));
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if (linux_cmdline)
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grub_efi_free_pages((grub_efi_physical_address_t)linux_cmdline, BYTES_TO_PAGES(params->cmdline_size + 1));
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if (kernel_mem)
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grub_efi_free_pages((grub_efi_physical_address_t)kernel_mem, BYTES_TO_PAGES(kernel_size));
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if (params)
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grub_efi_free_pages((grub_efi_physical_address_t)params, BYTES_TO_PAGES(16384));
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return GRUB_ERR_NONE;
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}
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static grub_err_t
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grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
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int argc, char *argv[])
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{
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grub_file_t *files = 0;
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int i, nfiles = 0;
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grub_size_t size = 0;
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grub_uint8_t *ptr;
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if (argc == 0)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
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goto fail;
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}
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if (!loaded)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, N_("you need to load the kernel first"));
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goto fail;
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}
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files = grub_zalloc (argc * sizeof (files[0]));
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if (!files)
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goto fail;
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for (i = 0; i < argc; i++)
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{
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grub_file_filter_disable_compression ();
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files[i] = grub_file_open (argv[i]);
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if (! files[i])
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goto fail;
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nfiles++;
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size += ALIGN_UP (grub_file_size (files[i]), 4);
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}
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initrd_mem = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(size));
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if (!initrd_mem)
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{
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grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate initrd"));
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goto fail;
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}
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params->ramdisk_size = size;
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params->ramdisk_image = (grub_uint32_t)(grub_uint64_t) initrd_mem;
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ptr = initrd_mem;
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for (i = 0; i < nfiles; i++)
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{
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grub_ssize_t cursize = grub_file_size (files[i]);
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if (grub_file_read (files[i], ptr, cursize) != cursize)
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{
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if (!grub_errno)
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grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
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argv[i]);
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goto fail;
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}
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ptr += cursize;
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grub_memset (ptr, 0, ALIGN_UP_OVERHEAD (cursize, 4));
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ptr += ALIGN_UP_OVERHEAD (cursize, 4);
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}
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params->ramdisk_size = size;
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fail:
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for (i = 0; i < nfiles; i++)
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grub_file_close (files[i]);
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grub_free (files);
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if (initrd_mem && grub_errno)
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grub_efi_free_pages((grub_efi_physical_address_t)initrd_mem, BYTES_TO_PAGES(size));
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return grub_errno;
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}
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static grub_err_t
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grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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int argc, char *argv[])
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{
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grub_file_t file = 0;
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struct linux_kernel_header lh;
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grub_ssize_t len, start, filelen;
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void *kernel;
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grub_dl_ref (my_mod);
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if (argc == 0)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
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goto fail;
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}
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file = grub_file_open (argv[0]);
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if (! file)
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goto fail;
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filelen = grub_file_size (file);
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kernel = grub_malloc(filelen);
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if (!kernel)
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{
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grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel buffer"));
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goto fail;
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}
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if (grub_file_read (file, kernel, filelen) != filelen)
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{
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grub_error (GRUB_ERR_FILE_READ_ERROR, N_("Can't read kernel %s"), argv[0]);
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goto fail;
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}
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if (! grub_linuxefi_secure_validate (kernel, filelen))
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{
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grub_error (GRUB_ERR_INVALID_COMMAND, N_("%s has invalid signature"), argv[0]);
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grub_free (kernel);
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goto fail;
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}
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grub_file_seek (file, 0);
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grub_free(kernel);
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params = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(16384));
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if (! params)
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{
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grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate kernel parameters");
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goto fail;
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}
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memset (params, 0, 16384);
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if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))
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{
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if (!grub_errno)
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grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
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argv[0]);
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goto fail;
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}
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if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))
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{
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grub_error (GRUB_ERR_BAD_OS, N_("invalid magic number"));
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goto fail;
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}
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if (lh.setup_sects > GRUB_LINUX_MAX_SETUP_SECTS)
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{
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grub_error (GRUB_ERR_BAD_OS, N_("too many setup sectors"));
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goto fail;
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}
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if (lh.version < grub_cpu_to_le16 (0x020b))
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{
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grub_error (GRUB_ERR_BAD_OS, N_("kernel too old"));
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goto fail;
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}
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if (!lh.handover_offset)
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{
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grub_error (GRUB_ERR_BAD_OS, N_("kernel doesn't support EFI handover"));
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goto fail;
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}
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linux_cmdline = grub_efi_allocate_pages_max(0x3fffffff,
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BYTES_TO_PAGES(lh.cmdline_size + 1));
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if (!linux_cmdline)
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{
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grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate cmdline"));
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goto fail;
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}
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grub_memcpy (linux_cmdline, LINUX_IMAGE, sizeof (LINUX_IMAGE));
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grub_create_loader_cmdline (argc, argv,
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linux_cmdline + sizeof (LINUX_IMAGE) - 1,
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lh.cmdline_size - (sizeof (LINUX_IMAGE) - 1));
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grub_pass_verity_hash(&lh, linux_cmdline);
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lh.cmd_line_ptr = (grub_uint32_t)(grub_uint64_t)linux_cmdline;
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handover_offset = lh.handover_offset;
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start = (lh.setup_sects + 1) * 512;
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len = grub_file_size(file) - start;
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kernel_mem = grub_efi_allocate_pages(lh.pref_address,
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BYTES_TO_PAGES(lh.init_size));
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if (!kernel_mem)
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kernel_mem = grub_efi_allocate_pages_max(0x3fffffff,
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BYTES_TO_PAGES(lh.init_size));
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if (!kernel_mem)
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{
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grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate kernel"));
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goto fail;
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}
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if (grub_file_seek (file, start) == (grub_off_t) -1)
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{
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grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
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argv[0]);
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goto fail;
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}
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if (grub_file_read (file, kernel_mem, len) != len && !grub_errno)
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{
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grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
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argv[0]);
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}
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if (grub_errno == GRUB_ERR_NONE)
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{
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grub_loader_set (grub_linuxefi_boot, grub_linuxefi_unload, 0);
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loaded = 1;
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lh.code32_start = (grub_uint32_t)(grub_uint64_t) kernel_mem;
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}
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memcpy(params, &lh, 2 * 512);
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params->type_of_loader = 0x21;
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fail:
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if (file)
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grub_file_close (file);
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if (grub_errno != GRUB_ERR_NONE)
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{
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grub_dl_unref (my_mod);
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loaded = 0;
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}
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if (linux_cmdline && !loaded)
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grub_efi_free_pages((grub_efi_physical_address_t)linux_cmdline, BYTES_TO_PAGES(lh.cmdline_size + 1));
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if (kernel_mem && !loaded)
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grub_efi_free_pages((grub_efi_physical_address_t)kernel_mem, BYTES_TO_PAGES(kernel_size));
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if (params && !loaded)
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grub_efi_free_pages((grub_efi_physical_address_t)params, BYTES_TO_PAGES(16384));
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return grub_errno;
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}
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static grub_command_t cmd_linux, cmd_initrd;
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GRUB_MOD_INIT(linuxefi)
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{
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cmd_linux =
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grub_register_command ("linuxefi", grub_cmd_linux,
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0, N_("Load Linux."));
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cmd_initrd =
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grub_register_command ("initrdefi", grub_cmd_initrd,
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0, N_("Load initrd."));
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my_mod = mod;
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}
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GRUB_MOD_FINI(linuxefi)
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{
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grub_unregister_command (cmd_linux);
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grub_unregister_command (cmd_initrd);
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}
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