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grub/grub-core/loader/multiboot.c
Alexey Makhalov 61ff5602fe relocator: Protect grub_relocator_alloc_chunk_align() max_addr against integer underflow 
This commit introduces integer underflow mitigation in max_addr calculation
in grub_relocator_alloc_chunk_align() invocation.

It consists of 2 fixes:
  1. Introduced grub_relocator_alloc_chunk_align_safe() wrapper function to perform
     sanity check for min/max and size values, and to make safe invocation of
     grub_relocator_alloc_chunk_align() with validated max_addr value. Replace all
     invocations such as grub_relocator_alloc_chunk_align(..., min_addr, max_addr - size, size, ...)
     by grub_relocator_alloc_chunk_align_safe(..., min_addr, max_addr, size, ...).
  2. Introduced UP_TO_TOP32(s) macro for the cases where max_addr is 32-bit top
     address (0xffffffff - size + 1) or similar.

Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-07-29 16:55:48 +02:00

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/* multiboot.c - boot a multiboot OS image. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009,2010 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* FIXME: The following features from the Multiboot specification still
* need to be implemented:
* - drives table
* - ROM configuration table
* - SMBIOS tables
* - Networking information
*/
#include <grub/loader.h>
#include <grub/command.h>
#ifdef GRUB_USE_MULTIBOOT2
#include <grub/multiboot2.h>
#define GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER GRUB_MULTIBOOT2_CONSOLE_FRAMEBUFFER
#define GRUB_MULTIBOOT_CONSOLE_EGA_TEXT GRUB_MULTIBOOT2_CONSOLE_EGA_TEXT
#define GRUB_MULTIBOOT(x) grub_multiboot2_ ## x
#else
#include <grub/multiboot.h>
#define GRUB_MULTIBOOT(x) grub_multiboot_ ## x
#endif
#include <grub/cpu/multiboot.h>
#include <grub/elf.h>
#include <grub/aout.h>
#include <grub/file.h>
#include <grub/err.h>
#include <grub/dl.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/env.h>
#include <grub/cpu/relocator.h>
#include <grub/video.h>
#include <grub/memory.h>
#include <grub/i18n.h>
GRUB_MOD_LICENSE ("GPLv3+");
#ifdef GRUB_MACHINE_EFI
#include <grub/efi/efi.h>
#endif
struct grub_relocator *GRUB_MULTIBOOT (relocator) = NULL;
grub_uint32_t GRUB_MULTIBOOT (payload_eip);
#if defined (GRUB_MACHINE_PCBIOS) || defined (GRUB_MACHINE_MULTIBOOT) || defined (GRUB_MACHINE_COREBOOT) || defined (GRUB_MACHINE_QEMU)
#define DEFAULT_VIDEO_MODE "text"
#else
#define DEFAULT_VIDEO_MODE "auto"
#endif
static int accepts_video;
static int accepts_ega_text;
static int console_required;
static grub_dl_t my_mod;
/* Helper for grub_get_multiboot_mmap_count. */
static int
count_hook (grub_uint64_t addr __attribute__ ((unused)),
grub_uint64_t size __attribute__ ((unused)),
grub_memory_type_t type __attribute__ ((unused)), void *data)
{
grub_size_t *count = data;
(*count)++;
return 0;
}
/* Return the length of the Multiboot mmap that will be needed to allocate
our platform's map. */
grub_uint32_t
GRUB_MULTIBOOT (get_mmap_count) (void)
{
grub_size_t count = 0;
grub_mmap_iterate (count_hook, &count);
return count;
}
grub_err_t
GRUB_MULTIBOOT (set_video_mode) (void)
{
grub_err_t err;
const char *modevar;
#if GRUB_MACHINE_HAS_VGA_TEXT
if (accepts_video)
#endif
{
modevar = grub_env_get ("gfxpayload");
if (! modevar || *modevar == 0)
err = grub_video_set_mode (DEFAULT_VIDEO_MODE, 0, 0);
else
{
char *tmp;
tmp = grub_xasprintf ("%s;" DEFAULT_VIDEO_MODE, modevar);
if (! tmp)
return grub_errno;
err = grub_video_set_mode (tmp, 0, 0);
grub_free (tmp);
}
}
#if GRUB_MACHINE_HAS_VGA_TEXT
else
err = grub_video_set_mode ("text", 0, 0);
#endif
return err;
}
#ifdef GRUB_MACHINE_EFI
#ifdef __x86_64__
#define grub_relocator_efi_boot grub_relocator64_efi_boot
#define grub_relocator_efi_state grub_relocator64_efi_state
#endif
#endif
#ifdef grub_relocator_efi_boot
static void
efi_boot (struct grub_relocator *rel,
grub_uint32_t target)
{
#ifdef GRUB_USE_MULTIBOOT2
struct grub_relocator_efi_state state_efi = MULTIBOOT2_EFI_INITIAL_STATE;
#else
struct grub_relocator_efi_state state_efi = MULTIBOOT_EFI_INITIAL_STATE;
#endif
state_efi.MULTIBOOT_EFI_ENTRY_REGISTER = GRUB_MULTIBOOT (payload_eip);
state_efi.MULTIBOOT_EFI_MBI_REGISTER = target;
grub_relocator_efi_boot (rel, state_efi);
}
#else
#define grub_efi_is_finished 1
static void
efi_boot (struct grub_relocator *rel __attribute__ ((unused)),
grub_uint32_t target __attribute__ ((unused)))
{
}
#endif
#if defined (__i386__) || defined (__x86_64__)
static void
normal_boot (struct grub_relocator *rel, struct grub_relocator32_state state)
{
grub_relocator32_boot (rel, state, 0);
}
#else
static void
normal_boot (struct grub_relocator *rel, struct grub_relocator32_state state)
{
grub_relocator32_boot (rel, state);
}
#endif
static grub_err_t
grub_multiboot_boot (void)
{
grub_err_t err;
#ifdef GRUB_USE_MULTIBOOT2
struct grub_relocator32_state state = MULTIBOOT2_INITIAL_STATE;
#else
struct grub_relocator32_state state = MULTIBOOT_INITIAL_STATE;
#endif
state.MULTIBOOT_ENTRY_REGISTER = GRUB_MULTIBOOT (payload_eip);
err = GRUB_MULTIBOOT (make_mbi) (&state.MULTIBOOT_MBI_REGISTER);
if (err)
return err;
if (grub_efi_is_finished)
normal_boot (GRUB_MULTIBOOT (relocator), state);
else
efi_boot (GRUB_MULTIBOOT (relocator), state.MULTIBOOT_MBI_REGISTER);
/* Not reached. */
return GRUB_ERR_NONE;
}
static grub_err_t
grub_multiboot_unload (void)
{
GRUB_MULTIBOOT (free_mbi) ();
grub_relocator_unload (GRUB_MULTIBOOT (relocator));
GRUB_MULTIBOOT (relocator) = NULL;
grub_dl_unref (my_mod);
return GRUB_ERR_NONE;
}
static grub_uint64_t highest_load;
#define MULTIBOOT_LOAD_ELF64
#include "multiboot_elfxx.c"
#undef MULTIBOOT_LOAD_ELF64
#define MULTIBOOT_LOAD_ELF32
#include "multiboot_elfxx.c"
#undef MULTIBOOT_LOAD_ELF32
/* Load ELF32 or ELF64. */
grub_err_t
GRUB_MULTIBOOT (load_elf) (mbi_load_data_t *mld)
{
if (grub_multiboot_is_elf32 (mld->buffer))
return grub_multiboot_load_elf32 (mld);
else if (grub_multiboot_is_elf64 (mld->buffer))
return grub_multiboot_load_elf64 (mld);
return grub_error (GRUB_ERR_UNKNOWN_OS, N_("invalid arch-dependent ELF magic"));
}
grub_err_t
GRUB_MULTIBOOT (set_console) (int console_type, int accepted_consoles,
int width, int height, int depth,
int console_req)
{
console_required = console_req;
if (!(accepted_consoles
& (GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER
| (GRUB_MACHINE_HAS_VGA_TEXT ? GRUB_MULTIBOOT_CONSOLE_EGA_TEXT : 0))))
{
if (console_required)
return grub_error (GRUB_ERR_BAD_OS,
"OS requires a console but none is available");
grub_puts_ (N_("WARNING: no console will be available to OS"));
accepts_video = 0;
accepts_ega_text = 0;
return GRUB_ERR_NONE;
}
if (console_type == GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER)
{
char *buf;
if (depth && width && height)
buf = grub_xasprintf ("%dx%dx%d,%dx%d,auto", width,
height, depth, width, height);
else if (width && height)
buf = grub_xasprintf ("%dx%d,auto", width, height);
else
buf = grub_strdup ("auto");
if (!buf)
return grub_errno;
grub_env_set ("gfxpayload", buf);
grub_free (buf);
}
else
{
#if GRUB_MACHINE_HAS_VGA_TEXT
grub_env_set ("gfxpayload", "text");
#else
/* Always use video if no VGA text is available. */
grub_env_set ("gfxpayload", "auto");
#endif
}
accepts_video = !!(accepted_consoles & GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER);
accepts_ega_text = !!(accepted_consoles & GRUB_MULTIBOOT_CONSOLE_EGA_TEXT);
return GRUB_ERR_NONE;
}
static grub_err_t
grub_cmd_multiboot (grub_command_t cmd __attribute__ ((unused)),
int argc, char *argv[])
{
grub_file_t file = 0;
grub_err_t err;
grub_loader_unset ();
highest_load = 0;
#ifndef GRUB_USE_MULTIBOOT2
grub_multiboot_quirks = GRUB_MULTIBOOT_QUIRKS_NONE;
int option_found = 0;
do
{
option_found = 0;
if (argc != 0 && grub_strcmp (argv[0], "--quirk-bad-kludge") == 0)
{
argc--;
argv++;
option_found = 1;
grub_multiboot_quirks |= GRUB_MULTIBOOT_QUIRK_BAD_KLUDGE;
}
if (argc != 0 && grub_strcmp (argv[0], "--quirk-modules-after-kernel") == 0)
{
argc--;
argv++;
option_found = 1;
grub_multiboot_quirks |= GRUB_MULTIBOOT_QUIRK_MODULES_AFTER_KERNEL;
}
} while (option_found);
#endif
if (argc == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
file = grub_file_open (argv[0], GRUB_FILE_TYPE_MULTIBOOT_KERNEL);
if (! file)
return grub_errno;
grub_dl_ref (my_mod);
/* Skip filename. */
GRUB_MULTIBOOT (init_mbi) (argc - 1, argv + 1);
grub_relocator_unload (GRUB_MULTIBOOT (relocator));
GRUB_MULTIBOOT (relocator) = grub_relocator_new ();
if (!GRUB_MULTIBOOT (relocator))
goto fail;
err = GRUB_MULTIBOOT (load) (file, argv[0]);
if (err)
goto fail;
GRUB_MULTIBOOT (set_bootdev) ();
grub_loader_set (grub_multiboot_boot, grub_multiboot_unload, 0);
fail:
if (file)
grub_file_close (file);
if (grub_errno != GRUB_ERR_NONE)
{
grub_relocator_unload (GRUB_MULTIBOOT (relocator));
GRUB_MULTIBOOT (relocator) = NULL;
grub_dl_unref (my_mod);
}
return grub_errno;
}
static grub_err_t
grub_cmd_module (grub_command_t cmd __attribute__ ((unused)),
int argc, char *argv[])
{
grub_file_t file = 0;
grub_ssize_t size;
void *module = NULL;
grub_addr_t target;
grub_err_t err;
int nounzip = 0;
grub_uint64_t lowest_addr = 0;
if (argc == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
if (grub_strcmp (argv[0], "--nounzip") == 0)
{
argv++;
argc--;
nounzip = 1;
}
if (argc == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
if (!GRUB_MULTIBOOT (relocator))
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("you need to load the kernel first"));
file = grub_file_open (argv[0], GRUB_FILE_TYPE_MULTIBOOT_MODULE
| (nounzip ? GRUB_FILE_TYPE_NO_DECOMPRESS : GRUB_FILE_TYPE_NONE));
if (! file)
return grub_errno;
#ifndef GRUB_USE_MULTIBOOT2
lowest_addr = 0x100000;
if (grub_multiboot_quirks & GRUB_MULTIBOOT_QUIRK_MODULES_AFTER_KERNEL)
lowest_addr = ALIGN_UP (highest_load + 1048576, 4096);
#endif
size = grub_file_size (file);
if (size)
{
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
lowest_addr, UP_TO_TOP32 (size),
size, MULTIBOOT_MOD_ALIGN,
GRUB_RELOCATOR_PREFERENCE_NONE, 1);
if (err)
{
grub_file_close (file);
return err;
}
module = get_virtual_current_address (ch);
target = get_physical_target_address (ch);
}
else
{
module = 0;
target = 0;
}
err = GRUB_MULTIBOOT (add_module) (target, size, argc - 1, argv + 1);
if (err)
{
grub_file_close (file);
return err;
}
if (size && grub_file_read (file, module, size) != size)
{
grub_file_close (file);
if (!grub_errno)
grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
argv[0]);
return grub_errno;
}
grub_file_close (file);
return GRUB_ERR_NONE;
}
static grub_command_t cmd_multiboot, cmd_module;
GRUB_MOD_INIT(multiboot)
{
cmd_multiboot =
#ifdef GRUB_USE_MULTIBOOT2
grub_register_command ("multiboot2", grub_cmd_multiboot,
0, N_("Load a multiboot 2 kernel."));
cmd_module =
grub_register_command ("module2", grub_cmd_module,
0, N_("Load a multiboot 2 module."));
#else
grub_register_command ("multiboot", grub_cmd_multiboot,
0, N_("Load a multiboot kernel."));
cmd_module =
grub_register_command ("module", grub_cmd_module,
0, N_("Load a multiboot module."));
#endif
my_mod = mod;
}
GRUB_MOD_FINI(multiboot)
{
grub_unregister_command (cmd_multiboot);
grub_unregister_command (cmd_module);
}
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