grub/grub-core/kern/ia64/efi/init.c

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/* init.c - initialize an ia64-based EFI system */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2008 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/>.
*/
#include <grub/types.h>
#include <grub/misc.h>
#include <grub/mm.h>
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#include <grub/time.h>
#include <grub/err.h>
#include <grub/dl.h>
#include <grub/kernel.h>
#include <grub/efi/efi.h>
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#include <grub/loader.h>
static grub_uint64_t divisor = 1;
static grub_uint64_t
get_itc (void)
{
grub_uint64_t ret;
asm volatile ("mov %0=ar.itc" : "=r" (ret));
return ret;
}
grub_uint64_t
grub_rtc_get_time_ms (void)
{
return get_itc () / divisor;
}
void
grub_machine_init (void)
{
grub_efi_event_t event;
grub_uint64_t before, after;
grub_efi_uintn_t idx;
grub_efi_init ();
efi_call_5 (grub_efi_system_table->boot_services->create_event,
GRUB_EFI_EVT_TIMER, GRUB_EFI_TPL_CALLBACK, 0, 0, &event);
before = get_itc ();
efi_call_3 (grub_efi_system_table->boot_services->set_timer, event,
GRUB_EFI_TIMER_RELATIVE, 200000);
efi_call_3 (grub_efi_system_table->boot_services->wait_for_event, 1,
&event, &idx);
after = get_itc ();
efi_call_1 (grub_efi_system_table->boot_services->close_event, event);
divisor = (after - before + 5) / 20;
if (divisor == 0)
divisor = 800000;
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grub_install_get_time_ms (grub_rtc_get_time_ms);
}
void
grub_machine_fini (int flags)
{
efi: Fix use-after-free in halt/reboot path commit 92bfc33db984 ("efi: Free malloc regions on exit") introduced memory freeing in grub_efi_fini(), which is used not only by exit path but by halt/reboot one as well. As result of memory freeing, code and data regions used by modules, such as halt, reboot, acpi (used by halt) also got freed. After return to module code, CPU executes, filled by UEFI firmware (tested with edk2), 0xAFAFAFAF pattern as a code. Which leads to #UD exception later. grub> halt !!!! X64 Exception Type - 06(#UD - Invalid Opcode) CPU Apic ID - 00000000 !!!! RIP - 0000000003F4EC28, CS - 0000000000000038, RFLAGS - 0000000000200246 RAX - 0000000000000000, RCX - 00000000061DA188, RDX - 0A74C0854DC35D41 RBX - 0000000003E10E08, RSP - 0000000007F0F860, RBP - 0000000000000000 RSI - 00000000064DB768, RDI - 000000000832C5C3 R8 - 0000000000000002, R9 - 0000000000000000, R10 - 00000000061E2E52 R11 - 0000000000000020, R12 - 0000000003EE5C1F, R13 - 00000000061E0FF4 R14 - 0000000003E10D80, R15 - 00000000061E2F60 DS - 0000000000000030, ES - 0000000000000030, FS - 0000000000000030 GS - 0000000000000030, SS - 0000000000000030 CR0 - 0000000080010033, CR2 - 0000000000000000, CR3 - 0000000007C01000 CR4 - 0000000000000668, CR8 - 0000000000000000 DR0 - 0000000000000000, DR1 - 0000000000000000, DR2 - 0000000000000000 DR3 - 0000000000000000, DR6 - 00000000FFFF0FF0, DR7 - 0000000000000400 GDTR - 00000000079EEA98 0000000000000047, LDTR - 0000000000000000 IDTR - 0000000007598018 0000000000000FFF, TR - 0000000000000000 FXSAVE_STATE - 0000000007F0F4C0 Proposal here is to continue to free allocated memory for exit boot services path but keep it for halt/reboot path as it won't be much security concern here. Introduced GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY loader flag to be used by efi halt/reboot path. Signed-off-by: Alexey Makhalov <amakhalov@vmware.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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if (!(flags & GRUB_LOADER_FLAG_NORETURN))
return;
grub_efi_fini ();
if (!(flags & GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY))
grub_efi_memory_fini ();
}