14ceb3b3ff
Loaders rely on global variables for saving context which is consumed in the boot hook and freed in the unload hook. In the case where a loader command is executed twice, calling grub_loader_set() a second time executes the unload hook, but in some cases this runs when the loader's global context has already been updated, resulting in the updated context being freed and potential use-after-free bugs when the boot hook is subsequently called. This adds a new API, grub_loader_set_ex(), which allows a loader to specify context that is passed to its boot and unload hooks. This is an alternative to requiring that loaders call grub_loader_unset() before mutating their global context. Signed-off-by: Chris Coulson <chris.coulson@canonical.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
85 lines
2.9 KiB
C
85 lines
2.9 KiB
C
/* loader.h - OS loaders */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2002,2003,2004,2006,2007,2009 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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#ifndef GRUB_LOADER_HEADER
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#define GRUB_LOADER_HEADER 1
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#include <grub/file.h>
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#include <grub/symbol.h>
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#include <grub/err.h>
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#include <grub/types.h>
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/* Check if a loader is loaded. */
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int EXPORT_FUNC (grub_loader_is_loaded) (void);
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/* Set loader functions. */
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enum
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{
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GRUB_LOADER_FLAG_NORETURN = 1,
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GRUB_LOADER_FLAG_PXE_NOT_UNLOAD = 2,
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GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY = 4,
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};
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void EXPORT_FUNC (grub_loader_set) (grub_err_t (*boot) (void),
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grub_err_t (*unload) (void),
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int flags);
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void EXPORT_FUNC (grub_loader_set_ex) (grub_err_t (*boot) (void *context),
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grub_err_t (*unload) (void *context),
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void *context,
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int flags);
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/* Unset current loader, if any. */
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void EXPORT_FUNC (grub_loader_unset) (void);
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/* Call the boot hook in current loader. This may or may not return,
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depending on the setting by grub_loader_set. */
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grub_err_t grub_loader_boot (void);
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/* The space between numbers is intentional for the simplicity of adding new
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values even if external modules use them. */
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typedef enum {
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/* A preboot hook which can use everything and turns nothing off. */
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GRUB_LOADER_PREBOOT_HOOK_PRIO_NORMAL = 400,
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/* A preboot hook which can't use disks and may stop disks. */
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GRUB_LOADER_PREBOOT_HOOK_PRIO_DISK = 300,
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/* A preboot hook which can't use disks or console and may stop console. */
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GRUB_LOADER_PREBOOT_HOOK_PRIO_CONSOLE = 200,
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/* A preboot hook which can't use disks or console, can't modify memory map
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and may stop memory services or finalize memory map. */
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GRUB_LOADER_PREBOOT_HOOK_PRIO_MEMORY = 100,
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} grub_loader_preboot_hook_prio_t;
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/* Register a preboot hook. */
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struct grub_preboot;
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struct grub_preboot *EXPORT_FUNC(grub_loader_register_preboot_hook) (grub_err_t (*preboot_func) (int noret),
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grub_err_t (*preboot_rest_func) (void),
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grub_loader_preboot_hook_prio_t prio);
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/* Unregister given preboot hook. */
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void EXPORT_FUNC (grub_loader_unregister_preboot_hook) (struct grub_preboot *hnd);
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#ifndef GRUB_MACHINE_EMU
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void grub_boot_init (void);
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void grub_boot_fini (void);
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#endif
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#endif /* ! GRUB_LOADER_HEADER */
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