mirror of
https://src.fedoraproject.org/rpms/grub2.git
synced 2024-11-24 14:32:58 +00:00
74 lines
2.6 KiB
Diff
74 lines
2.6 KiB
Diff
|
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
|
||
|
|
Date: Thu, 3 Mar 2022 13:10:56 +0100
|
||
|
|
Subject: [PATCH] grub-core/loader/i386/efi/linux.c: do not validate kernels
|
||
|
|
twice
|
||
|
|
|
||
|
|
On codebases that have shim-lock-verifier built into the grub core
|
||
|
|
(like 2.06 upstream), shim-lock-verifier is in enforcing mode when
|
||
|
|
booted with secureboot. It means that grub_cmd_linux() command
|
||
|
|
attempts to perform shim validate upon opening linux kernel image,
|
||
|
|
including kernel measurement. And the verifier correctly returns file
|
||
|
|
open error when shim validate protocol is not present or shim fails to
|
||
|
|
validate the kernel.
|
||
|
|
|
||
|
|
This makes the call to grub_linuxefi_secure_validate() redundant, but
|
||
|
|
also harmful. As validating the kernel image twice, extends the PCRs
|
||
|
|
with the same measurement twice. Which breaks existing sealing
|
||
|
|
policies when upgrading from grub2.04+rhboot+sb+linuxefi to
|
||
|
|
grub2.06+rhboot+sb+linuxefi builds. It is also incorrect to measure
|
||
|
|
the kernel twice.
|
||
|
|
|
||
|
|
This patch must not be ported to older editions of grub code bases
|
||
|
|
that do not have verifiers framework, or it is not builtin, or
|
||
|
|
shim-lock-verifier is an optional module.
|
||
|
|
|
||
|
|
This patch is tested to ensure that unsigned kernels are not possible
|
||
|
|
to boot in secureboot mode when shim rejects kernel, or shim protocol
|
||
|
|
is missing, and that the measurements become stable once again. The
|
||
|
|
above also ensures that CVE-2020-15705 is not reintroduced.
|
||
|
|
|
||
|
|
Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
|
||
|
|
---
|
||
|
|
grub-core/loader/i386/efi/linux.c | 13 -------------
|
||
|
|
1 file changed, 13 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
|
||
|
|
index 3cf0f9b330b..941df6400b9 100644
|
||
|
|
--- a/grub-core/loader/i386/efi/linux.c
|
||
|
|
+++ b/grub-core/loader/i386/efi/linux.c
|
||
|
|
@@ -30,7 +30,6 @@
|
||
|
|
#include <grub/cpu/efi/memory.h>
|
||
|
|
#include <grub/tpm.h>
|
||
|
|
#include <grub/safemath.h>
|
||
|
|
-#include <grub/efi/sb.h>
|
||
|
|
|
||
|
|
GRUB_MOD_LICENSE ("GPLv3+");
|
||
|
|
|
||
|
|
@@ -278,7 +277,6 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
|
||
|
|
grub_ssize_t start, filelen;
|
||
|
|
void *kernel = NULL;
|
||
|
|
int setup_header_end_offset;
|
||
|
|
- int rc;
|
||
|
|
|
||
|
|
grub_dl_ref (my_mod);
|
||
|
|
|
||
|
|
@@ -308,17 +306,6 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
|
||
|
|
goto fail;
|
||
|
|
}
|
||
|
|
|
||
|
|
- if (grub_efi_get_secureboot () == GRUB_EFI_SECUREBOOT_MODE_ENABLED)
|
||
|
|
- {
|
||
|
|
- rc = grub_linuxefi_secure_validate (kernel, filelen);
|
||
|
|
- if (rc <= 0)
|
||
|
|
- {
|
||
|
|
- grub_error (GRUB_ERR_INVALID_COMMAND,
|
||
|
|
- N_("%s has invalid signature"), argv[0]);
|
||
|
|
- goto fail;
|
||
|
|
- }
|
||
|
|
- }
|
||
|
|
-
|
||
|
|
lh = (struct linux_i386_kernel_header *)kernel;
|
||
|
|
grub_dprintf ("linux", "original lh is at %p\n", kernel);
|
||
|
|
|