NetCube-Systems-Austria/kumquat-buildroot
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
7a68960b68
kumquat-buildroot/boot/grub2/0141-util-mkimage-Add-an-option-to-import-SBAT-metadata-i.patch
Stefan Sørensen 1bad507220 boot/grub2: Backport 2021/03/02 securify fixes 
Details: https://lists.gnu.org/archive/html/grub-devel/2021-03/msg00007.html

As detailed in commit 7e64a050fb, it is
difficult to utilize the upstream patches directly, so a number of
patches include changes to generated files so that we don't need invoke
the gentpl.py script.

In addition to the security fixes, these required patches has been
backported:

  f76a27996 efi: Make shim_lock GUID and protocol type public
  04ae030d0 efi: Return grub_efi_status_t from grub_efi_get_variable()
  ac5c93675 efi: Add a function to read EFI variables with attributes
  d7e54b2e5 efi: Add secure boot detection

The following security issues are fixed:

CVE-2020-14372 grub2: The acpi command allows privileged user to load crafted
               ACPI tables when Secure Boot is enabled
CWE-184
7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

GRUB2 enables the use of the command acpi even when Secure Boot is signaled by
the firmware. An attacker with local root privileges to can drop a small SSDT
in /boot/efi and modify grub.cfg to instruct grub to load said SSDT. The SSDT
then gets run by the kernel and it overwrites the kernel lock down configuration
enabling the attacker to load unsigned kernel modules and kexec unsigned code.

Reported-by: Máté Kukri

*******************************************************************************

CVE-2020-25632 grub2: Use-after-free in rmmod command
CWE-416
7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

The rmmod implementation for GRUB2 is flawed, allowing an attacker to unload
a module used as dependency without checking if any other dependent module is
still loaded. This leads to an use-after-free scenario possibly allowing an
attacker to execute arbitrary code and by-pass Secure Boot protections.

Reported-by: Chris Coulson (Canonical)

*******************************************************************************

CVE-2020-25647 grub2: Out-of-bound write in grub_usb_device_initialize()
CWE-787
6.9/CVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

grub_usb_device_initialize() is called to handle USB device initialization. It
reads out the descriptors it needs from the USB device and uses that data to
fill in some USB data structures. grub_usb_device_initialize() performs very
little bounds checking and simply assumes the USB device provides sane values.
This behavior can trigger memory corruption. If properly exploited, this would
lead to arbitrary code execution allowing the attacker to by-pass Secure Boot
mechanism.

Reported-by: Joseph Tartaro (IOActive) and Ilja van Sprundel (IOActive)

*******************************************************************************

CVE-2020-27749 grub2: Stack buffer overflow in grub_parser_split_cmdline
CWE-121
7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

grub_parser_split_cmdline() expands variable names present in the supplied
command line in to their corresponding variable contents and uses a 1kB stack
buffer for temporary storage without sufficient bounds checking. If the
function is called with a command line that references a variable with a
sufficiently large payload, it is possible to overflow the stack buffer,
corrupt the stack frame and control execution. An attacker may use this to
circumvent Secure Boot protections.

Reported-by: Chris Coulson (Canonical)

*******************************************************************************

CVE-2020-27779 grub2: The cutmem command allows privileged user to remove
               memory regions when Secure Boot is enabled
CWE-285
7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

The GRUB2's cutmem command does not honor Secure Boot locking. This allows an
privileged attacker to remove address ranges from memory creating an
opportunity to circumvent Secure Boot protections after proper triage about
grub's memory layout.

Reported-by: Teddy Reed

*******************************************************************************

CVE-2021-3418 - grub2: GRUB 2.05 reintroduced CVE-2020-15705
CWE-281
6.4/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

The GRUB2 upstream reintroduced the CVE-2020-15705. This refers to a distro
specific flaw which made upstream in the mentioned version.

If certificates that signed GRUB2 are installed into db, GRUB2 can be booted
directly. It will then boot any kernel without signature validation. The booted
kernel will think it was booted in Secure Boot mode and will implement lock
down, yet it could have been tampered.

This flaw only affects upstream and distributions using the shim_lock verifier.

Reported-by: Dimitri John Ledkov (Canonical)

*******************************************************************************

CVE-2021-20225 grub2: Heap out-of-bounds write in short form option parser
CWE-787
7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

The option parser in GRUB2 allows an attacker to write past the end of
a heap-allocated buffer by calling certain commands with a large number
of specific short forms of options.

Reported-by: Daniel Axtens (IBM)

*******************************************************************************

CVE-2021-20233 grub2: Heap out-of-bound write due to mis-calculation of
               space required for quoting
CWE-787
7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

There's a flaw on GRUB2 menu rendering code setparam_prefix() in the menu
rendering code performs a length calculation on the assumption that expressing
a quoted single quote will require 3 characters, while it actually requires
4 characters. This allow an attacker to corrupt memory by one byte for each
quote in the input.

Reported-by: Daniel Axtens (IBM)

*******************************************************************************

Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
2021-03-14 08:24:24 +01:00

265 lines
10 KiB
Diff
Raw Blame History

From b11547137703bbc642114a816233a5b6fed61b06 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Mon, 15 Feb 2021 17:07:00 +0100
Subject: [PATCH] util/mkimage: Add an option to import SBAT metadata into a
.sbat section
Add a --sbat option to the grub-mkimage tool which allows us to import
an SBAT metadata formatted as a CSV file into a .sbat section of the
EFI binary.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
---
docs/grub.texi | 19 +++++++++++++++++++
include/grub/util/install.h | 3 ++-
include/grub/util/mkimage.h | 1 +
util/grub-install-common.c | 2 +-
util/grub-mkimage.c | 15 ++++++++++++++-
util/mkimage.c | 43 ++++++++++++++++++++++++++++++++++++-------
6 files changed, 73 insertions(+), 10 deletions(-)
diff --git a/docs/grub.texi b/docs/grub.texi
index 8518cc0..bff6dfc 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5616,6 +5616,7 @@ environment variables and commands are listed in the same order.
* Authentication and authorisation:: Users and access control
* Using digital signatures:: Booting digitally signed code
* UEFI secure boot and shim:: Booting digitally signed PE files
+* Secure Boot Advanced Targeting:: Embedded information for generation number based revocation
* Measured Boot:: Measuring boot components
* Lockdown:: Lockdown when booting on a secure setup
@end menu
@@ -5795,6 +5796,24 @@ and @command{memrw} will not be available when the UEFI secure boot is enabled.
This is done for security reasons and are enforced by the GRUB Lockdown mechanism
(@pxref{Lockdown}).
+@node Secure Boot Advanced Targeting
+@section Embedded information for generation number based revocation
+
+The Secure Boot Advanced Targeting (SBAT) is a mechanism to allow the revocation
+of components in the boot path by using generation numbers embedded into the EFI
+binaries. The SBAT metadata is located in an .sbat data section that has set of
+UTF-8 strings as comma-separated values (CSV). See
+@uref{https://github.com/rhboot/shim/blob/main/SBAT.md} for more details.
+
+To add a data section containing the SBAT information into the binary, the
+@option{--sbat} option of @command{grub-mkimage} command should be used. The content
+of a CSV file, encoded with UTF-8, is copied as is to the .sbat data section into
+the generated EFI binary. The CSV file can be stored anywhere on the file system.
+
+@example
+grub-mkimage -O x86_64-efi -o grubx64.efi -p '(tftp)/grub' --sbat sbat.csv efinet tftp
+@end example
+
@node Measured Boot
@section Measuring boot components
diff --git a/include/grub/util/install.h b/include/grub/util/install.h
index 2631b10..c03befd 100644
--- a/include/grub/util/install.h
+++ b/include/grub/util/install.h
@@ -183,7 +183,8 @@ grub_install_generate_image (const char *dir, const char *prefix,
char *config_path,
const struct grub_install_image_target_desc *image_target,
int note,
- grub_compression_t comp, const char *dtb_file);
+ grub_compression_t comp, const char *dtb_file,
+ const char *sbat_path);
const struct grub_install_image_target_desc *
grub_install_get_image_target (const char *arg);
diff --git a/include/grub/util/mkimage.h b/include/grub/util/mkimage.h
index ba9f568..3819a67 100644
--- a/include/grub/util/mkimage.h
+++ b/include/grub/util/mkimage.h
@@ -24,6 +24,7 @@ struct grub_mkimage_layout
size_t exec_size;
size_t kernel_size;
size_t bss_size;
+ size_t sbat_size;
grub_uint64_t start_address;
void *reloc_section;
size_t reloc_size;
diff --git a/util/grub-install-common.c b/util/grub-install-common.c
index 0295d40..5d43ed1 100644
--- a/util/grub-install-common.c
+++ b/util/grub-install-common.c
@@ -511,7 +511,7 @@ grub_install_make_image_wrap_file (const char *dir, const char *prefix,
grub_install_generate_image (dir, prefix, fp, outname,
modules.entries, memdisk_path,
pubkeys, npubkeys, config_path, tgt,
- note, compression, dtb);
+ note, compression, dtb, NULL);
while (dc--)
grub_install_pop_module ();
}
diff --git a/util/grub-mkimage.c b/util/grub-mkimage.c
index 912564e..75b8847 100644
--- a/util/grub-mkimage.c
+++ b/util/grub-mkimage.c
@@ -81,6 +81,7 @@ static struct argp_option options[] = {
{"output", 'o', N_("FILE"), 0, N_("output a generated image to FILE [default=stdout]"), 0},
{"format", 'O', N_("FORMAT"), 0, 0, 0},
{"compression", 'C', "(xz|none|auto)", 0, N_("choose the compression to use for core image"), 0},
+ {"sbat", 's', N_("FILE"), 0, N_("SBAT metadata"), 0},
{"verbose", 'v', 0, 0, N_("print verbose messages."), 0},
{ 0, 0, 0, 0, 0, 0 }
};
@@ -123,6 +124,7 @@ struct arguments
size_t npubkeys;
char *font;
char *config;
+ char *sbat;
int note;
const struct grub_install_image_target_desc *image_target;
grub_compression_t comp;
@@ -224,6 +226,13 @@ argp_parser (int key, char *arg, struct argp_state *state)
arguments->prefix = xstrdup (arg);
break;
+ case 's':
+ if (arguments->sbat)
+ free (arguments->sbat);
+
+ arguments->sbat = xstrdup (arg);
+ break;
+
case 'v':
verbosity++;
break;
@@ -309,7 +318,8 @@ main (int argc, char *argv[])
arguments.memdisk, arguments.pubkeys,
arguments.npubkeys, arguments.config,
arguments.image_target, arguments.note,
- arguments.comp, arguments.dtb);
+ arguments.comp, arguments.dtb,
+ arguments.sbat);
if (grub_util_file_sync (fp) < 0)
grub_util_error (_("cannot sync `%s': %s"), arguments.output ? : "stdout",
@@ -328,5 +338,8 @@ main (int argc, char *argv[])
if (arguments.output)
free (arguments.output);
+ if (arguments.sbat)
+ free (arguments.sbat);
+
return 0;
}
diff --git a/util/mkimage.c b/util/mkimage.c
index 8b475a6..b354ec1 100644
--- a/util/mkimage.c
+++ b/util/mkimage.c
@@ -869,12 +869,13 @@ grub_install_generate_image (const char *dir, const char *prefix,
char *memdisk_path, char **pubkey_paths,
size_t npubkeys, char *config_path,
const struct grub_install_image_target_desc *image_target,
- int note, grub_compression_t comp, const char *dtb_path)
+ int note, grub_compression_t comp, const char *dtb_path,
+ const char *sbat_path)
{
char *kernel_img, *core_img;
size_t total_module_size, core_size;
size_t memdisk_size = 0, config_size = 0;
- size_t prefix_size = 0, dtb_size = 0;
+ size_t prefix_size = 0, dtb_size = 0, sbat_size = 0;
char *kernel_path;
size_t offset;
struct grub_util_path_list *path_list, *p;
@@ -925,6 +926,9 @@ grub_install_generate_image (const char *dir, const char *prefix,
total_module_size += dtb_size + sizeof (struct grub_module_header);
}
+ if (sbat_path != NULL && image_target->id != IMAGE_EFI)
+ grub_util_error (_(".sbat section can be embedded into EFI images only"));
+
if (config_path)
{
config_size = ALIGN_ADDR (grub_util_get_image_size (config_path) + 1);
@@ -1289,8 +1293,9 @@ grub_install_generate_image (const char *dir, const char *prefix,
break;
case IMAGE_EFI:
{
- char *pe_img, *header;
+ char *pe_img, *pe_sbat, *header;
struct grub_pe32_section_table *section;
+ size_t n_sections = 4;
size_t scn_size;
grub_uint32_t vma, raw_data;
size_t pe_size, header_size;
@@ -1305,8 +1310,15 @@ grub_install_generate_image (const char *dir, const char *prefix,
header_size = EFI64_HEADER_SIZE;
vma = raw_data = header_size;
+
+ if (sbat_path != NULL)
+ {
+ sbat_size = ALIGN_ADDR (grub_util_get_image_size (sbat_path));
+ sbat_size = ALIGN_UP (sbat_size, GRUB_PE32_FILE_ALIGNMENT);
+ }
+
pe_size = ALIGN_UP (header_size + core_size, GRUB_PE32_FILE_ALIGNMENT) +
- ALIGN_UP (layout.reloc_size, GRUB_PE32_FILE_ALIGNMENT);
+ ALIGN_UP (layout.reloc_size, GRUB_PE32_FILE_ALIGNMENT) + sbat_size;
header = pe_img = xcalloc (1, pe_size);
memcpy (pe_img + raw_data, core_img, core_size);
@@ -1321,7 +1333,10 @@ grub_install_generate_image (const char *dir, const char *prefix,
+ GRUB_PE32_SIGNATURE_SIZE);
c->machine = grub_host_to_target16 (image_target->pe_target);
- c->num_sections = grub_host_to_target16 (4);
+ if (sbat_path != NULL)
+ n_sections++;
+
+ c->num_sections = grub_host_to_target16 (n_sections);
c->time = grub_host_to_target32 (STABLE_EMBEDDING_TIMESTAMP);
c->characteristics = grub_host_to_target16 (GRUB_PE32_EXECUTABLE_IMAGE
| GRUB_PE32_LINE_NUMS_STRIPPED
@@ -1383,7 +1398,8 @@ grub_install_generate_image (const char *dir, const char *prefix,
GRUB_PE32_SCN_MEM_READ);
scn_size = ALIGN_UP (layout.kernel_size - layout.exec_size, GRUB_PE32_FILE_ALIGNMENT);
- PE_OHDR (o32, o64, data_size) = grub_host_to_target32 (scn_size +
+ /* ALIGN_UP (sbat_size, GRUB_PE32_FILE_ALIGNMENT) is done earlier. */
+ PE_OHDR (o32, o64, data_size) = grub_host_to_target32 (scn_size + sbat_size +
ALIGN_UP (total_module_size,
GRUB_PE32_FILE_ALIGNMENT));
@@ -1394,7 +1410,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
GRUB_PE32_SCN_MEM_READ |
GRUB_PE32_SCN_MEM_WRITE);
- scn_size = pe_size - layout.reloc_size - raw_data;
+ scn_size = pe_size - layout.reloc_size - sbat_size - raw_data;
section = init_pe_section (image_target, section, "mods",
&vma, scn_size, image_target->section_align,
&raw_data, scn_size,
@@ -1402,6 +1418,19 @@ grub_install_generate_image (const char *dir, const char *prefix,
GRUB_PE32_SCN_MEM_READ |
GRUB_PE32_SCN_MEM_WRITE);
+ if (sbat_path != NULL)
+ {
+ pe_sbat = pe_img + raw_data;
+ grub_util_load_image (sbat_path, pe_sbat);
+
+ section = init_pe_section (image_target, section, ".sbat",
+ &vma, sbat_size,
+ image_target->section_align,
+ &raw_data, sbat_size,
+ GRUB_PE32_SCN_CNT_INITIALIZED_DATA |
+ GRUB_PE32_SCN_MEM_READ);
+ }
+
scn_size = layout.reloc_size;
PE_OHDR (o32, o64, base_relocation_table.rva) = grub_host_to_target32 (vma);
PE_OHDR (o32, o64, base_relocation_table.size) = grub_host_to_target32 (scn_size);
--
2.14.2
Reference in New Issue View Git Blame Copy Permalink