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kern/efi/init: Log a console error during a stack check failure

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The initial implementation of the stack protector just busy looped
in __stack_chk_fail in order to reduce the amount of code being
executed after the stack has been compromised because of a lack of
firmware memory protections. With future firmware implementations
incorporating memory protections such as W^X, call in to boot services
when an error occurs in order to log a message to the console before
automatically rebooting the machine.

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Chris Coulson 2022-03-21 15:14:39 +00:00 committed by Daniel Kiper
parent a97d1ebb8e
commit 37ddd9457f
2 changed files with 24 additions and 3 deletions
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4
grub-core/Makefile.core.def
View File

@ -50,12 +50,14 @@ kernel = {
nostrip = emu;
emu_ldflags = '-Wl,-r';
i386_efi_cflags = '-fshort-wchar';
i386_efi_ldflags = '-Wl,-r';
i386_efi_stripflags = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
x86_64_efi_cflags = '-fshort-wchar';
x86_64_efi_ldflags = '-Wl,-r';
x86_64_efi_stripflags = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';
ia64_efi_cflags = '-fno-builtin -fpic -minline-int-divide-max-throughput';
ia64_efi_cflags = '-fshort-wchar -fno-builtin -fpic -minline-int-divide-max-throughput';
ia64_efi_ldflags = '-Wl,-r';
ia64_efi_stripflags = '--strip-unneeded -K start -R .note -R .comment -R .note.gnu.gold-version';

23
grub-core/kern/efi/init.c
View File

@ -31,6 +31,11 @@
#ifdef GRUB_STACK_PROTECTOR
static grub_efi_char16_t stack_chk_fail_msg[] =
L"* GRUB: STACK SMASHING DETECTED!!! *\r\n"
L"* GRUB: ABORTED!!! *\r\n"
L"* GRUB: REBOOTING IN 5 SECONDS... *\r\n";
static grub_efi_guid_t rng_protocol_guid = GRUB_EFI_RNG_PROTOCOL_GUID;
/*
@ -44,9 +49,23 @@ grub_addr_t __stack_chk_guard;
void __attribute__ ((noreturn))
__stack_chk_fail (void)
{
grub_efi_simple_text_output_interface_t *o;
/*
* Assume it's not safe to call into EFI Boot Services. Sorry, that
* means no console message here.
* Use ConOut here rather than StdErr. StdErr only goes to
* the serial console, at least on EDK2.
*/
o = grub_efi_system_table->con_out;
efi_call_2 (o->output_string, o, stack_chk_fail_msg);
efi_call_1 (grub_efi_system_table->boot_services->stall, 5000000);
efi_call_4 (grub_efi_system_table->runtime_services->reset_system,
GRUB_EFI_RESET_SHUTDOWN, GRUB_EFI_ABORTED, 0, NULL);
/*
* We shouldn't get here. It's unsafe to return because the stack
* is compromised and this function is noreturn, so just busy
* loop forever.
*/
do
{