fix CVE-2020-27779-and-CVE-2020-14372

(cherry picked from commit dc4c6f5053acddc771b57cab9dccc8183043d940)
This commit is contained in:
shirely16 2021-03-16 19:12:31 +08:00 committed by openeuler-sync-bot
parent 271a199337
commit 67a196e077
14 changed files with 1259 additions and 1 deletions

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@ -0,0 +1,129 @@
From ea5950d8597278ba9066f24d7abcee403f825668 Mon Sep 17 00:00:00 2001
From: Marco A Benatto <mbenatto@redhat.com>
Date: Wed, 23 Sep 2020 11:33:33 -0400
Subject: [PATCH 07/46] verifiers: Move verifiers API to kernel image
Move verifiers API from a module to the kernel image, so it can be
used there as well. There are no functional changes in this patch.
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/Makefile.am | 1 +
grub-core/Makefile.core.def | 6 +-----
grub-core/kern/main.c | 4 ++++
grub-core/{commands => kern}/verifiers.c | 8 ++------
include/grub/verify.h | 9 ++++++---
5 files changed, 14 insertions(+), 14 deletions(-)
rename grub-core/{commands => kern}/verifiers.c (97%)
diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
index 5ff3afd62..3569b7101 100644
--- a/grub-core/Makefile.am
+++ b/grub-core/Makefile.am
@@ -91,6 +91,7 @@ KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/parser.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/partition.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/term.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/time.h
+KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/verify.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/mm_private.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/net.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/memory.h
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 072b1628c..5cb869f5b 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -140,6 +140,7 @@ kernel = {
common = kern/rescue_reader.c;
common = kern/term.c;
common = kern/backtrace.c;
+ common = kern/verifiers.c;
x86 = kern/i386/backtrace.c;
i386_xen = kern/i386/backtrace.c;
@@ -943,11 +944,6 @@ module = {
cppflags = '-I$(srcdir)/lib/posix_wrap';
};
-module = {
- name = verifiers;
- common = commands/verifiers.c;
-};
-
module = {
name = shim_lock;
common = commands/efi/shim_lock.c;
diff --git a/grub-core/kern/main.c b/grub-core/kern/main.c
index 9cad0c448..73967e2f5 100644
--- a/grub-core/kern/main.c
+++ b/grub-core/kern/main.c
@@ -29,6 +29,7 @@
#include <grub/command.h>
#include <grub/reader.h>
#include <grub/parser.h>
+#include <grub/verify.h>
#ifdef GRUB_MACHINE_PCBIOS
#include <grub/machine/memory.h>
@@ -274,6 +275,9 @@ grub_main (void)
grub_boot_time ("After machine init.");
+ /* Init verifiers API. */
+ grub_verifiers_init ();
+
grub_load_config ();
grub_boot_time ("Before loading embedded modules.");
diff --git a/grub-core/commands/verifiers.c b/grub-core/kern/verifiers.c
similarity index 97%
rename from grub-core/commands/verifiers.c
rename to grub-core/kern/verifiers.c
index 7b9297cd3..3d19bffd1 100644
--- a/grub-core/commands/verifiers.c
+++ b/grub-core/kern/verifiers.c
@@ -218,12 +218,8 @@ grub_verify_string (char *str, enum grub_verify_string_type type)
return GRUB_ERR_NONE;
}
-GRUB_MOD_INIT(verifiers)
+void
+grub_verifiers_init (void)
{
grub_file_filter_register (GRUB_FILE_FILTER_VERIFY, grub_verifiers_open);
}
-
-GRUB_MOD_FINI(verifiers)
-{
- grub_file_filter_unregister (GRUB_FILE_FILTER_VERIFY);
-}
diff --git a/include/grub/verify.h b/include/grub/verify.h
index ea0491433..cd129c398 100644
--- a/include/grub/verify.h
+++ b/include/grub/verify.h
@@ -64,7 +64,10 @@ struct grub_file_verifier
grub_err_t (*verify_string) (char *str, enum grub_verify_string_type type);
};
-extern struct grub_file_verifier *grub_file_verifiers;
+extern struct grub_file_verifier *EXPORT_VAR (grub_file_verifiers);
+
+extern void
+grub_verifiers_init (void);
static inline void
grub_verifier_register (struct grub_file_verifier *ver)
@@ -78,7 +81,7 @@ grub_verifier_unregister (struct grub_file_verifier *ver)
grub_list_remove (GRUB_AS_LIST (ver));
}
-grub_err_t
-grub_verify_string (char *str, enum grub_verify_string_type type);
+extern grub_err_t
+EXPORT_FUNC (grub_verify_string) (char *str, enum grub_verify_string_type type);
#endif /* ! GRUB_VERIFY_HEADER */
--
2.26.2

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@ -0,0 +1,430 @@
From 1aebb5645e749917034444b24b88825ea557cae9 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Mon, 28 Sep 2020 20:08:02 +0200
Subject: [PATCH 09/46] kern: Add lockdown support
When the GRUB starts on a secure boot platform, some commands can be
used to subvert the protections provided by the verification mechanism and
could lead to booting untrusted system.
To prevent that situation, allow GRUB to be locked down. That way the code
may check if GRUB has been locked down and further restrict the commands
that are registered or what subset of their functionality could be used.
The lockdown support adds the following components:
* The grub_lockdown() function which can be used to lockdown GRUB if,
e.g., UEFI Secure Boot is enabled.
* The grub_is_lockdown() function which can be used to check if the GRUB
was locked down.
* A verifier that flags OS kernels, the GRUB modules, Device Trees and ACPI
tables as GRUB_VERIFY_FLAGS_DEFER_AUTH to defer verification to other
verifiers. These files are only successfully verified if another registered
verifier returns success. Otherwise, the whole verification process fails.
For example, PE/COFF binaries verification can be done by the shim_lock
verifier which validates the signatures using the shim_lock protocol.
However, the verification is not deferred directly to the shim_lock verifier.
The shim_lock verifier is hooked into the verification process instead.
* A set of grub_{command,extcmd}_lockdown functions that can be used by
code registering command handlers, to only register unsafe commands if
the GRUB has not been locked down.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
conf/Makefile.common | 2 +
docs/grub-dev.texi | 27 +++++++++++++
docs/grub.texi | 8 ++++
grub-core/Makefile.am | 5 ++-
grub-core/Makefile.core.def | 1 +
grub-core/commands/extcmd.c | 23 +++++++++++
grub-core/kern/command.c | 24 +++++++++++
grub-core/kern/lockdown.c | 80 +++++++++++++++++++++++++++++++++++++
include/grub/command.h | 5 +++
include/grub/extcmd.h | 7 ++++
include/grub/lockdown.h | 44 ++++++++++++++++++++
11 files changed, 225 insertions(+), 1 deletion(-)
create mode 100644 grub-core/kern/lockdown.c
create mode 100644 include/grub/lockdown.h
diff --git a/conf/Makefile.common b/conf/Makefile.common
index 6cd71cbb2..2a1a886f6 100644
--- a/conf/Makefile.common
+++ b/conf/Makefile.common
@@ -84,7 +84,9 @@ CPPFLAGS_PARTTOOL_LIST = -Dgrub_parttool_register=PARTTOOL_LIST_MARKER
CPPFLAGS_TERMINAL_LIST = '-Dgrub_term_register_input(...)=INPUT_TERMINAL_LIST_MARKER(__VA_ARGS__)'
CPPFLAGS_TERMINAL_LIST += '-Dgrub_term_register_output(...)=OUTPUT_TERMINAL_LIST_MARKER(__VA_ARGS__)'
CPPFLAGS_COMMAND_LIST = '-Dgrub_register_command(...)=COMMAND_LIST_MARKER(__VA_ARGS__)'
+CPPFLAGS_COMMAND_LIST += '-Dgrub_register_command_lockdown(...)=COMMAND_LOCKDOWN_LIST_MARKER(__VA_ARGS__)'
CPPFLAGS_COMMAND_LIST += '-Dgrub_register_extcmd(...)=EXTCOMMAND_LIST_MARKER(__VA_ARGS__)'
+CPPFLAGS_COMMAND_LIST += '-Dgrub_register_extcmd_lockdown(...)=EXTCOMMAND_LOCKDOWN_LIST_MARKER(__VA_ARGS__)'
CPPFLAGS_COMMAND_LIST += '-Dgrub_register_command_p1(...)=P1COMMAND_LIST_MARKER(__VA_ARGS__)'
CPPFLAGS_FDT_LIST := '-Dgrub_fdtbus_register(...)=FDT_DRIVER_LIST_MARKER(__VA_ARGS__)'
CPPFLAGS_MARKER = $(CPPFLAGS_FS_LIST) $(CPPFLAGS_VIDEO_LIST) \
diff --git a/docs/grub-dev.texi b/docs/grub-dev.texi
index ee389fd83..635ec7231 100644
--- a/docs/grub-dev.texi
+++ b/docs/grub-dev.texi
@@ -86,6 +86,7 @@ This edition documents version @value{VERSION}.
* PFF2 Font File Format::
* Graphical Menu Software Design::
* Verifiers framework::
+* Lockdown framework::
* Copying This Manual:: Copying This Manual
* Index::
@end menu
@@ -2086,6 +2087,32 @@ Optionally at the end of the file @samp{fini}, if it exists, is called with just
the context. If you return no error during any of @samp{init}, @samp{write} and
@samp{fini} then the file is considered as having succeded verification.
+@node Lockdown framework
+@chapter Lockdown framework
+
+The GRUB can be locked down, which is a restricted mode where some operations
+are not allowed. For instance, some commands cannot be used when the GRUB is
+locked down.
+
+The function
+@code{grub_lockdown()} is used to lockdown GRUB and the function
+@code{grub_is_lockdown()} function can be used to check whether lockdown is
+enabled or not. When enabled, the function returns @samp{GRUB_LOCKDOWN_ENABLED}
+and @samp{GRUB_LOCKDOWN_DISABLED} when is not enabled.
+
+The following functions can be used to register the commands that can only be
+used when lockdown is disabled:
+
+@itemize
+
+@item @code{grub_cmd_lockdown()} registers command which should not run when the
+GRUB is in lockdown mode.
+
+@item @code{grub_cmd_lockdown()} registers extended command which should not run
+when the GRUB is in lockdown mode.
+
+@end itemize
+
@node Copying This Manual
@appendix Copying This Manual
diff --git a/docs/grub.texi b/docs/grub.texi
index d3fbc81db..a459a71e4 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5598,6 +5598,7 @@ environment variables and commands are listed in the same order.
* Using digital signatures:: Booting digitally signed code
* UEFI secure boot and shim:: Booting digitally signed PE files
* Measured Boot:: Measuring boot components
+* Lockdown:: Lockdown when booting on a secure setup
@end menu
@node Authentication and authorisation
@@ -5812,6 +5813,13 @@ into @file{core.img} in order to avoid a potential gap in measurement between
Measured boot is currently only supported on EFI platforms.
+@node Lockdown
+@section Lockdown when booting on a secure setup
+
+The GRUB can be locked down when booted on a secure boot environment, for example
+if the UEFI secure boot is enabled. On a locked down configuration, the GRUB will
+be restricted and some operations/commands cannot be executed.
+
@node Platform limitations
@chapter Platform limitations
diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
index 3569b7101..6b2e5e139 100644
--- a/grub-core/Makefile.am
+++ b/grub-core/Makefile.am
@@ -80,6 +80,7 @@ KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/fs.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/i18n.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/kernel.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/list.h
+KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/lockdown.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/misc.h
if COND_emu
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/compiler-rt-emu.h
@@ -378,8 +379,10 @@ command.lst: $(MARKER_FILES)
b=`basename $$pp .marker`; \
sed -n \
-e "/EXTCOMMAND_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/*\1: $$b/;p;}" \
+ -e "/EXTCOMMAND_LOCKDOWN_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/*\1: $$b/;p;}" \
-e "/P1COMMAND_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/*\1: $$b/;p;}" \
- -e "/COMMAND_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/\1: $$b/;p;}" $$pp; \
+ -e "/COMMAND_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/\1: $$b/;p;}" \
+ -e "/COMMAND_LOCKDOWN_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/\1: $$b/;p;}" $$pp; \
done) | sort -u > $@
platform_DATA += command.lst
CLEANFILES += command.lst
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 8c8f8c579..a00e7f983 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -205,6 +205,7 @@ kernel = {
efi = term/efi/console.c;
efi = kern/acpi.c;
efi = kern/efi/acpi.c;
+ efi = kern/lockdown.c;
efi = lib/envblk.c;
i386_coreboot = kern/i386/pc/acpi.c;
i386_multiboot = kern/i386/pc/acpi.c;
diff --git a/grub-core/commands/extcmd.c b/grub-core/commands/extcmd.c
index 69574e2b0..90a5ca24a 100644
--- a/grub-core/commands/extcmd.c
+++ b/grub-core/commands/extcmd.c
@@ -19,6 +19,7 @@
#include <grub/mm.h>
#include <grub/list.h>
+#include <grub/lockdown.h>
#include <grub/misc.h>
#include <grub/extcmd.h>
#include <grub/script_sh.h>
@@ -110,6 +111,28 @@ grub_register_extcmd (const char *name, grub_extcmd_func_t func,
summary, description, parser, 1);
}
+static grub_err_t
+grub_extcmd_lockdown (grub_extcmd_context_t ctxt __attribute__ ((unused)),
+ int argc __attribute__ ((unused)),
+ char **argv __attribute__ ((unused)))
+{
+ return grub_error (GRUB_ERR_ACCESS_DENIED,
+ N_("%s: the command is not allowed when lockdown is enforced"),
+ ctxt->extcmd->cmd->name);
+}
+
+grub_extcmd_t
+grub_register_extcmd_lockdown (const char *name, grub_extcmd_func_t func,
+ grub_command_flags_t flags, const char *summary,
+ const char *description,
+ const struct grub_arg_option *parser)
+{
+ if (grub_is_lockdown () == GRUB_LOCKDOWN_ENABLED)
+ func = grub_extcmd_lockdown;
+
+ return grub_register_extcmd (name, func, flags, summary, description, parser);
+}
+
void
grub_unregister_extcmd (grub_extcmd_t ext)
{
diff --git a/grub-core/kern/command.c b/grub-core/kern/command.c
index acd721879..4aabcd4b5 100644
--- a/grub-core/kern/command.c
+++ b/grub-core/kern/command.c
@@ -17,6 +17,7 @@
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <grub/lockdown.h>
#include <grub/mm.h>
#include <grub/command.h>
@@ -77,6 +78,29 @@ grub_register_command_prio (const char *name,
return cmd;
}
+static grub_err_t
+grub_cmd_lockdown (grub_command_t cmd __attribute__ ((unused)),
+ int argc __attribute__ ((unused)),
+ char **argv __attribute__ ((unused)))
+
+{
+ return grub_error (GRUB_ERR_ACCESS_DENIED,
+ N_("%s: the command is not allowed when lockdown is enforced"),
+ cmd->name);
+}
+
+grub_command_t
+grub_register_command_lockdown (const char *name,
+ grub_command_func_t func,
+ const char *summary,
+ const char *description)
+{
+ if (grub_is_lockdown () == GRUB_LOCKDOWN_ENABLED)
+ func = grub_cmd_lockdown;
+
+ return grub_register_command_prio (name, func, summary, description, 0);
+}
+
void
grub_unregister_command (grub_command_t cmd)
{
diff --git a/grub-core/kern/lockdown.c b/grub-core/kern/lockdown.c
new file mode 100644
index 000000000..1e56c0b80
--- /dev/null
+++ b/grub-core/kern/lockdown.c
@@ -0,0 +1,80 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020 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/dl.h>
+#include <grub/file.h>
+#include <grub/lockdown.h>
+#include <grub/verify.h>
+
+static int lockdown = GRUB_LOCKDOWN_DISABLED;
+
+static grub_err_t
+lockdown_verifier_init (grub_file_t io __attribute__ ((unused)),
+ enum grub_file_type type,
+ void **context __attribute__ ((unused)),
+ enum grub_verify_flags *flags)
+{
+ *flags = GRUB_VERIFY_FLAGS_SKIP_VERIFICATION;
+
+ switch (type & GRUB_FILE_TYPE_MASK)
+ {
+ case GRUB_FILE_TYPE_GRUB_MODULE:
+ case GRUB_FILE_TYPE_LINUX_KERNEL:
+ case GRUB_FILE_TYPE_MULTIBOOT_KERNEL:
+ case GRUB_FILE_TYPE_XEN_HYPERVISOR:
+ case GRUB_FILE_TYPE_BSD_KERNEL:
+ case GRUB_FILE_TYPE_XNU_KERNEL:
+ case GRUB_FILE_TYPE_PLAN9_KERNEL:
+ case GRUB_FILE_TYPE_NTLDR:
+ case GRUB_FILE_TYPE_TRUECRYPT:
+ case GRUB_FILE_TYPE_FREEDOS:
+ case GRUB_FILE_TYPE_PXECHAINLOADER:
+ case GRUB_FILE_TYPE_PCCHAINLOADER:
+ case GRUB_FILE_TYPE_COREBOOT_CHAINLOADER:
+ case GRUB_FILE_TYPE_EFI_CHAINLOADED_IMAGE:
+ case GRUB_FILE_TYPE_ACPI_TABLE:
+ case GRUB_FILE_TYPE_DEVICE_TREE_IMAGE:
+ *flags = GRUB_VERIFY_FLAGS_DEFER_AUTH;
+
+ /* Fall through. */
+
+ default:
+ return GRUB_ERR_NONE;
+ }
+}
+
+struct grub_file_verifier lockdown_verifier =
+ {
+ .name = "lockdown_verifier",
+ .init = lockdown_verifier_init,
+ };
+
+void
+grub_lockdown (void)
+{
+ lockdown = GRUB_LOCKDOWN_ENABLED;
+
+ grub_verifier_register (&lockdown_verifier);
+}
+
+int
+grub_is_lockdown (void)
+{
+ return lockdown;
+}
diff --git a/include/grub/command.h b/include/grub/command.h
index eee4e847e..2a6f7f846 100644
--- a/include/grub/command.h
+++ b/include/grub/command.h
@@ -86,6 +86,11 @@ EXPORT_FUNC(grub_register_command_prio) (const char *name,
const char *summary,
const char *description,
int prio);
+grub_command_t
+EXPORT_FUNC(grub_register_command_lockdown) (const char *name,
+ grub_command_func_t func,
+ const char *summary,
+ const char *description);
void EXPORT_FUNC(grub_unregister_command) (grub_command_t cmd);
static inline grub_command_t
diff --git a/include/grub/extcmd.h b/include/grub/extcmd.h
index 19fe59266..fe9248b8b 100644
--- a/include/grub/extcmd.h
+++ b/include/grub/extcmd.h
@@ -62,6 +62,13 @@ grub_extcmd_t EXPORT_FUNC(grub_register_extcmd) (const char *name,
const char *description,
const struct grub_arg_option *parser);
+grub_extcmd_t EXPORT_FUNC(grub_register_extcmd_lockdown) (const char *name,
+ grub_extcmd_func_t func,
+ grub_command_flags_t flags,
+ const char *summary,
+ const char *description,
+ const struct grub_arg_option *parser);
+
grub_extcmd_t EXPORT_FUNC(grub_register_extcmd_prio) (const char *name,
grub_extcmd_func_t func,
grub_command_flags_t flags,
diff --git a/include/grub/lockdown.h b/include/grub/lockdown.h
new file mode 100644
index 000000000..40531fa82
--- /dev/null
+++ b/include/grub/lockdown.h
@@ -0,0 +1,44 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020 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/>.
+ */
+
+#ifndef GRUB_LOCKDOWN_H
+#define GRUB_LOCKDOWN_H 1
+
+#include <grub/symbol.h>
+
+#define GRUB_LOCKDOWN_DISABLED 0
+#define GRUB_LOCKDOWN_ENABLED 1
+
+#ifdef GRUB_MACHINE_EFI
+extern void
+EXPORT_FUNC (grub_lockdown) (void);
+extern int
+EXPORT_FUNC (grub_is_lockdown) (void);
+#else
+static inline void
+grub_lockdown (void)
+{
+}
+
+static inline int
+grub_is_lockdown (void)
+{
+ return GRUB_LOCKDOWN_DISABLED;
+}
+#endif
+#endif /* ! GRUB_LOCKDOWN_H */
--
2.26.2

View File

@ -0,0 +1,57 @@
From 959db537b12c5e76c244ccc51cbbed7f27b0abe2 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Tue, 2 Feb 2021 19:59:48 +0100
Subject: [PATCH 10/46] kern/lockdown: Set a variable if the GRUB is locked
down
It may be useful for scripts to determine whether the GRUB is locked
down or not. Add the lockdown variable which is set to "y" when the GRUB
is locked down.
Suggested-by: Dimitri John Ledkov <xnox@ubuntu.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
docs/grub.texi | 3 +++
grub-core/kern/lockdown.c | 4 ++++
2 files changed, 7 insertions(+)
diff --git a/docs/grub.texi b/docs/grub.texi
index a459a71e4..3a4d18e06 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5820,6 +5820,9 @@ The GRUB can be locked down when booted on a secure boot environment, for exampl
if the UEFI secure boot is enabled. On a locked down configuration, the GRUB will
be restricted and some operations/commands cannot be executed.
+The @samp{lockdown} variable is set to @samp{y} when the GRUB is locked down.
+Otherwise it does not exit.
+
@node Platform limitations
@chapter Platform limitations
diff --git a/grub-core/kern/lockdown.c b/grub-core/kern/lockdown.c
index 1e56c0b80..0bc70fd42 100644
--- a/grub-core/kern/lockdown.c
+++ b/grub-core/kern/lockdown.c
@@ -18,6 +18,7 @@
*/
#include <grub/dl.h>
+#include <grub/env.h>
#include <grub/file.h>
#include <grub/lockdown.h>
#include <grub/verify.h>
@@ -71,6 +72,9 @@ grub_lockdown (void)
lockdown = GRUB_LOCKDOWN_ENABLED;
grub_verifier_register (&lockdown_verifier);
+
+ grub_env_set ("lockdown", "y");
+ grub_env_export ("lockdown");
}
int
--
2.26.2

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@ -0,0 +1,54 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Mon, 28 Sep 2020 20:08:29 +0200
Subject: [PATCH] efi: Lockdown the GRUB when the UEFI Secure Boot is enabled
If the UEFI Secure Boot is enabled then the GRUB must be locked down
to prevent executing code that can potentially be used to subvert its
verification mechanisms.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/kern/efi/init.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c
index 2ffb520..634e3ac 100644
--- a/grub-core/kern/efi/init.c
+++ b/grub-core/kern/efi/init.c
@@ -20,6 +20,8 @@
#include <grub/efi/efi.h>
#include <grub/efi/console.h>
#include <grub/efi/disk.h>
+#include <grub/efi/sb.h>
+#include <grub/lockdown.h>
#include <grub/term.h>
#include <grub/misc.h>
#include <grub/env.h>
@@ -88,6 +90,23 @@ grub_efi_init (void)
/* Initialize the memory management system. */
grub_efi_mm_init ();
+ /*
+ * Lockdown the GRUB and register the shim_lock verifier
+ * if the UEFI Secure Boot is enabled.
+ */
+ if (grub_efi_secure_boot ())
+ {
+ grub_lockdown ();
+
+ /*
+ * TODO: Move GRUB to using the shim_lock verifier and
+ * enable the lockdown verifier.
+ */
+#if 0
+ grub_shim_lock_verifier_setup ();
+#endif
+ }
+
efi_call_4 (grub_efi_system_table->boot_services->set_watchdog_timer,
0, 0, 0, NULL);
--
2.23.0

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@ -0,0 +1,129 @@
From 8f73052885892bc0dbc01e297f79d7cf4925e491 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Mon, 28 Sep 2020 20:08:33 +0200
Subject: efi: Use grub_is_lockdown() instead of hardcoding a disabled modules
list
Now the GRUB can check if it has been locked down and this can be used to
prevent executing commands that can be utilized to circumvent the UEFI
Secure Boot mechanisms. So, instead of hardcoding a list of modules that
have to be disabled, prevent the usage of commands that can be dangerous.
This not only allows the commands to be disabled on other platforms, but
also properly separate the concerns. Since the shim_lock verifier logic
should be only about preventing to run untrusted binaries and not about
defining these kind of policies.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
docs/grub.texi | 15 +++++++-----
grub-core/commands/i386/wrmsr.c | 5 ++--
grub-core/commands/iorw.c | 19 +++++++--------
grub-core/commands/memrw.c | 19 +++++++--------
4 files changed, 32 insertions(+), 67 deletions(-)
diff --git a/grub-core/commands/i386/wrmsr.c b/grub-core/commands/i386/wrmsr.c
index 9c5e510eb..56a29c29f 100644
--- a/grub-core/commands/i386/wrmsr.c
+++ b/grub-core/commands/i386/wrmsr.c
@@ -24,6 +24,7 @@
#include <grub/env.h>
#include <grub/command.h>
#include <grub/extcmd.h>
+#include <grub/lockdown.h>
#include <grub/i18n.h>
#include <grub/i386/cpuid.h>
#include <grub/i386/wrmsr.h>
@@ -83,8 +84,8 @@ grub_cmd_msr_write (grub_command_t cmd __attribute__ ((unused)), int argc, char
GRUB_MOD_INIT(wrmsr)
{
- cmd_write = grub_register_command ("wrmsr", grub_cmd_msr_write, N_("ADDR VALUE"),
- N_("Write a value to a CPU model specific register."));
+ cmd_write = grub_register_command_lockdown ("wrmsr", grub_cmd_msr_write, N_("ADDR VALUE"),
+ N_("Write a value to a CPU model specific register."));
}
GRUB_MOD_FINI(wrmsr)
diff --git a/grub-core/commands/iorw.c b/grub-core/commands/iorw.c
index a0c164e54..584baec8f 100644
--- a/grub-core/commands/iorw.c
+++ b/grub-core/commands/iorw.c
@@ -23,6 +23,7 @@
#include <grub/cpu/io.h>
#include <grub/i18n.h>
#include <grub/efi/sb.h>
+#include <grub/lockdown.h>
GRUB_MOD_LICENSE ("GPLv3+");
@@ -131,17 +132,17 @@ GRUB_MOD_INIT(memrw)
N_("PORT"), N_("Read 32-bit value from PORT."),
options);
cmd_write_byte =
- grub_register_command ("outb", grub_cmd_write,
- N_("PORT VALUE [MASK]"),
- N_("Write 8-bit VALUE to PORT."));
+ grub_register_command_lockdown ("outb", grub_cmd_write,
+ N_("PORT VALUE [MASK]"),
+ N_("Write 8-bit VALUE to PORT."));
cmd_write_word =
- grub_register_command ("outw", grub_cmd_write,
- N_("PORT VALUE [MASK]"),
- N_("Write 16-bit VALUE to PORT."));
+ grub_register_command_lockdown ("outw", grub_cmd_write,
+ N_("PORT VALUE [MASK]"),
+ N_("Write 16-bit VALUE to PORT."));
cmd_write_dword =
- grub_register_command ("outl", grub_cmd_write,
- N_("ADDR VALUE [MASK]"),
- N_("Write 32-bit VALUE to PORT."));
+ grub_register_command_lockdown ("outl", grub_cmd_write,
+ N_("ADDR VALUE [MASK]"),
+ N_("Write 32-bit VALUE to PORT."));
}
GRUB_MOD_FINI(memrw)
diff --git a/grub-core/commands/memrw.c b/grub-core/commands/memrw.c
index 98769eadb..d401a6db0 100644
--- a/grub-core/commands/memrw.c
+++ b/grub-core/commands/memrw.c
@@ -22,6 +22,7 @@
#include <grub/env.h>
#include <grub/i18n.h>
#include <grub/efi/sb.h>
+#include <grub/lockdown.h>
GRUB_MOD_LICENSE ("GPLv3+");
@@ -133,17 +134,17 @@ GRUB_MOD_INIT(memrw)
N_("ADDR"), N_("Read 32-bit value from ADDR."),
options);
cmd_write_byte =
- grub_register_command ("write_byte", grub_cmd_write,
- N_("ADDR VALUE [MASK]"),
- N_("Write 8-bit VALUE to ADDR."));
+ grub_register_command_lockdown ("write_byte", grub_cmd_write,
+ N_("ADDR VALUE [MASK]"),
+ N_("Write 8-bit VALUE to ADDR."));
cmd_write_word =
- grub_register_command ("write_word", grub_cmd_write,
- N_("ADDR VALUE [MASK]"),
- N_("Write 16-bit VALUE to ADDR."));
+ grub_register_command_lockdown ("write_word", grub_cmd_write,
+ N_("ADDR VALUE [MASK]"),
+ N_("Write 16-bit VALUE to ADDR."));
cmd_write_dword =
- grub_register_command ("write_dword", grub_cmd_write,
- N_("ADDR VALUE [MASK]"),
- N_("Write 32-bit VALUE to ADDR."));
+ grub_register_command_lockdown ("write_dword", grub_cmd_write,
+ N_("ADDR VALUE [MASK]"),
+ N_("Write 32-bit VALUE to ADDR."));
}
GRUB_MOD_FINI(memrw)
--
2.23.0

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@ -0,0 +1,75 @@
From 08c63ad119ce0c0d0de56d9878f0be6811f623d4 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Mon, 28 Sep 2020 20:08:41 +0200
Subject: [PATCH 13/46] acpi: Don't register the acpi command when locked down
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The command is not allowed when lockdown is enforced. Otherwise an
attacker can instruct the GRUB to load an SSDT table to overwrite
the kernel lockdown configuration and later load and execute
unsigned code.
Fixes: CVE-2020-14372
Reported-by: Máté Kukri <km@mkukri.xyz>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
docs/grub.texi | 5 +++++
grub-core/commands/acpi.c | 15 ++++++++-------
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/docs/grub.texi b/docs/grub.texi
index 6d8d32b0b..2ee8721a1 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -3986,6 +3986,11 @@ Normally, this command will replace the Root System Description Pointer
(RSDP) in the Extended BIOS Data Area to point to the new tables. If the
@option{--no-ebda} option is used, the new tables will be known only to
GRUB, but may be used by GRUB's EFI emulation.
+
+Note: The command is not allowed when lockdown is enforced (@pxref{Lockdown}).
+ Otherwise an attacker can instruct the GRUB to load an SSDT table to
+ overwrite the kernel lockdown configuration and later load and execute
+ unsigned code.
@end deffn
diff --git a/grub-core/commands/acpi.c b/grub-core/commands/acpi.c
index 5a1499aa0..1215f2a62 100644
--- a/grub-core/commands/acpi.c
+++ b/grub-core/commands/acpi.c
@@ -27,6 +27,7 @@
#include <grub/mm.h>
#include <grub/memory.h>
#include <grub/i18n.h>
+#include <grub/lockdown.h>
#ifdef GRUB_MACHINE_EFI
#include <grub/efi/efi.h>
@@ -775,13 +776,13 @@ static grub_extcmd_t cmd;
GRUB_MOD_INIT(acpi)
{
- cmd = grub_register_extcmd ("acpi", grub_cmd_acpi, 0,
- N_("[-1|-2] [--exclude=TABLE1,TABLE2|"
- "--load-only=TABLE1,TABLE2] FILE1"
- " [FILE2] [...]"),
- N_("Load host ACPI tables and tables "
- "specified by arguments."),
- options);
+ cmd = grub_register_extcmd_lockdown ("acpi", grub_cmd_acpi, 0,
+ N_("[-1|-2] [--exclude=TABLE1,TABLE2|"
+ "--load-only=TABLE1,TABLE2] FILE1"
+ " [FILE2] [...]"),
+ N_("Load host ACPI tables and tables "
+ "specified by arguments."),
+ options);
}
GRUB_MOD_FINI(acpi)
--
2.26.2

View File

@ -0,0 +1,69 @@
From cbd4d630728847bcc3eb82c4a1667fc7ba6de73a Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 14 Oct 2020 16:33:42 +0200
Subject: [PATCH 14/46] mmap: Don't register cutmem and badram commands when
lockdown is enforced
The cutmem and badram commands can be used to remove EFI memory regions
and potentially disable the UEFI Secure Boot. Prevent the commands to be
registered if the GRUB is locked down.
Fixes: CVE-2020-27779
Reported-by: Teddy Reed <teddy.reed@gmail.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
docs/grub.texi | 4 ++++
grub-core/mmap/mmap.c | 13 +++++++------
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/docs/grub.texi b/docs/grub.texi
index 2ee8721a1..70bf91f40 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -4051,6 +4051,10 @@ this page is to be filtered. This syntax makes it easy to represent patterns
that are often result of memory damage, due to physical distribution of memory
cells.
+Note: The command is not allowed when lockdown is enforced (@pxref{Lockdown}).
+ This prevents removing EFI memory regions to potentially subvert the
+ security mechanisms provided by the UEFI secure boot.
+
@node blocklist
@subsection blocklist
diff --git a/grub-core/mmap/mmap.c b/grub-core/mmap/mmap.c
index 57b4e9a72..7ebf32e1e 100644
--- a/grub-core/mmap/mmap.c
+++ b/grub-core/mmap/mmap.c
@@ -20,6 +20,7 @@
#include <grub/memory.h>
#include <grub/machine/memory.h>
#include <grub/err.h>
+#include <grub/lockdown.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/command.h>
@@ -534,12 +535,12 @@ static grub_command_t cmd, cmd_cut;
GRUB_MOD_INIT(mmap)
{
- cmd = grub_register_command ("badram", grub_cmd_badram,
- N_("ADDR1,MASK1[,ADDR2,MASK2[,...]]"),
- N_("Declare memory regions as faulty (badram)."));
- cmd_cut = grub_register_command ("cutmem", grub_cmd_cutmem,
- N_("FROM[K|M|G] TO[K|M|G]"),
- N_("Remove any memory regions in specified range."));
+ cmd = grub_register_command_lockdown ("badram", grub_cmd_badram,
+ N_("ADDR1,MASK1[,ADDR2,MASK2[,...]]"),
+ N_("Declare memory regions as faulty (badram)."));
+ cmd_cut = grub_register_command_lockdown ("cutmem", grub_cmd_cutmem,
+ N_("FROM[K|M|G] TO[K|M|G]"),
+ N_("Remove any memory regions in specified range."));
}
--
2.26.2

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@ -0,0 +1,104 @@
From d1a40f870dbcb55280f57673c1d9c2c7110df42a Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 24 Feb 2021 09:00:05 +0100
Subject: [PATCH 15/46] commands: Restrict commands that can load BIOS or DT
blobs when locked down
There are some more commands that should be restricted when the GRUB is
locked down. Following is the list of commands and reasons to restrict:
* fakebios: creates BIOS-like structures for backward compatibility with
existing OSes. This should not be allowed when locked down.
* loadbios: reads a BIOS dump from storage and loads it. This action
should not be allowed when locked down.
* devicetree: loads a Device Tree blob and passes it to the OS. It replaces
any Device Tree provided by the firmware. This also should
not be allowed when locked down.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
docs/grub.texi | 3 +++
grub-core/commands/efi/loadbios.c | 16 ++++++++--------
grub-core/loader/arm/linux.c | 6 +++---
grub-core/loader/efi/fdt.c | 4 ++--
4 files changed, 16 insertions(+), 13 deletions(-)
diff --git a/docs/grub.texi b/docs/grub.texi
index 70bf91f40..cf29a1797 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -4236,6 +4236,9 @@ Load a device tree blob (.dtb) from a filesystem, for later use by a Linux
kernel. Does not perform merging with any device tree supplied by firmware,
but rather replaces it completely.
@ref{GNU/Linux}.
+
+Note: The command is not allowed when lockdown is enforced (@pxref{Lockdown}).
+ This is done to prevent subverting various security mechanisms.
@end deffn
@node distrust
diff --git a/grub-core/commands/efi/loadbios.c b/grub-core/commands/efi/loadbios.c
index d41d521a4..5c7725f8b 100644
--- a/grub-core/commands/efi/loadbios.c
+++ b/grub-core/commands/efi/loadbios.c
@@ -205,14 +205,14 @@ static grub_command_t cmd_fakebios, cmd_loadbios;
GRUB_MOD_INIT(loadbios)
{
- cmd_fakebios = grub_register_command ("fakebios", grub_cmd_fakebios,
- 0, N_("Create BIOS-like structures for"
- " backward compatibility with"
- " existing OS."));
-
- cmd_loadbios = grub_register_command ("loadbios", grub_cmd_loadbios,
- N_("BIOS_DUMP [INT10_DUMP]"),
- N_("Load BIOS dump."));
+ cmd_fakebios = grub_register_command_lockdown ("fakebios", grub_cmd_fakebios,
+ 0, N_("Create BIOS-like structures for"
+ " backward compatibility with"
+ " existing OS."));
+
+ cmd_loadbios = grub_register_command_lockdown ("loadbios", grub_cmd_loadbios,
+ N_("BIOS_DUMP [INT10_DUMP]"),
+ N_("Load BIOS dump."));
}
GRUB_MOD_FINI(loadbios)
diff --git a/grub-core/loader/arm/linux.c b/grub-core/loader/arm/linux.c
index d70c17486..ed23dc71e 100644
--- a/grub-core/loader/arm/linux.c
+++ b/grub-core/loader/arm/linux.c
@@ -493,9 +493,9 @@ GRUB_MOD_INIT (linux)
0, N_("Load Linux."));
cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd,
0, N_("Load initrd."));
- cmd_devicetree = grub_register_command ("devicetree", grub_cmd_devicetree,
- /* TRANSLATORS: DTB stands for device tree blob. */
- 0, N_("Load DTB file."));
+ cmd_devicetree = grub_register_command_lockdown ("devicetree", grub_cmd_devicetree,
+ /* TRANSLATORS: DTB stands for device tree blob. */
+ 0, N_("Load DTB file."));
my_mod = mod;
current_fdt = (const void *) grub_arm_firmware_get_boot_data ();
machine_type = grub_arm_firmware_get_machine_type ();
diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c
index ee9c5592c..003d07cd8 100644
--- a/grub-core/loader/efi/fdt.c
+++ b/grub-core/loader/efi/fdt.c
@@ -165,8 +165,8 @@ static grub_command_t cmd_devicetree;
GRUB_MOD_INIT (fdt)
{
cmd_devicetree =
- grub_register_command ("devicetree", grub_cmd_devicetree, 0,
- N_("Load DTB file."));
+ grub_register_command_lockdown ("devicetree", grub_cmd_devicetree, 0,
+ N_("Load DTB file."));
}
GRUB_MOD_FINI (fdt)
--
2.26.2

View File

@ -0,0 +1,37 @@
From 3e5b0593346fde8d92dd4e87ce15ff07e0cacf88 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 24 Feb 2021 22:59:59 +0100
Subject: [PATCH 16/46] commands/setpci: Restrict setpci command when locked
down
This command can set PCI devices register values, which makes it dangerous
in a locked down configuration. Restrict it so can't be used on this setup.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/commands/setpci.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/grub-core/commands/setpci.c b/grub-core/commands/setpci.c
index d5bc97d60..fa2ba7d89 100644
--- a/grub-core/commands/setpci.c
+++ b/grub-core/commands/setpci.c
@@ -329,10 +329,10 @@ static grub_extcmd_t cmd;
GRUB_MOD_INIT(setpci)
{
- cmd = grub_register_extcmd ("setpci", grub_cmd_setpci, 0,
- N_("[-s POSITION] [-d DEVICE] [-v VAR] "
- "REGISTER[=VALUE[:MASK]]"),
- N_("Manipulate PCI devices."), options);
+ cmd = grub_register_extcmd_lockdown ("setpci", grub_cmd_setpci, 0,
+ N_("[-s POSITION] [-d DEVICE] [-v VAR] "
+ "REGISTER[=VALUE[:MASK]]"),
+ N_("Manipulate PCI devices."), options);
}
GRUB_MOD_FINI(setpci)
--
2.26.2

View File

@ -0,0 +1,35 @@
From 75dd393392f16194904c8958a22fe12034f915a3 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 24 Feb 2021 12:59:29 +0100
Subject: [PATCH 17/46] commands/hdparm: Restrict hdparm command when locked
down
The command can be used to get/set ATA disk parameters. Some of these can
be dangerous since change the disk behavior. Restrict it when locked down.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/commands/hdparm.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/grub-core/commands/hdparm.c b/grub-core/commands/hdparm.c
index d3fa9661e..2e2319e64 100644
--- a/grub-core/commands/hdparm.c
+++ b/grub-core/commands/hdparm.c
@@ -436,9 +436,9 @@ static grub_extcmd_t cmd;
GRUB_MOD_INIT(hdparm)
{
- cmd = grub_register_extcmd ("hdparm", grub_cmd_hdparm, 0,
- N_("[OPTIONS] DISK"),
- N_("Get/set ATA disk parameters."), options);
+ cmd = grub_register_extcmd_lockdown ("hdparm", grub_cmd_hdparm, 0,
+ N_("[OPTIONS] DISK"),
+ N_("Get/set ATA disk parameters."), options);
}
GRUB_MOD_FINI(hdparm)
--
2.26.2

View File

@ -0,0 +1,61 @@
From a4df9a0d74376aa4fc82f8c86c280cb087de01be Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 24 Feb 2021 15:03:26 +0100
Subject: [PATCH 18/46] gdb: Restrict GDB access when locked down
The gdbstub* commands allow to start and control a GDB stub running on
local host that can be used to connect from a remote debugger. Restrict
this functionality when the GRUB is locked down.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/gdb/gdb.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)
diff --git a/grub-core/gdb/gdb.c b/grub-core/gdb/gdb.c
index 847a1e1e3..1818cb6f8 100644
--- a/grub-core/gdb/gdb.c
+++ b/grub-core/gdb/gdb.c
@@ -75,20 +75,24 @@ static grub_command_t cmd, cmd_stop, cmd_break;
GRUB_MOD_INIT (gdb)
{
grub_gdb_idtinit ();
- cmd = grub_register_command ("gdbstub", grub_cmd_gdbstub,
- N_("PORT"),
- /* TRANSLATORS: GDB stub is a small part of
- GDB functionality running on local host
- which allows remote debugger to
- connect to it. */
- N_("Start GDB stub on given port"));
- cmd_break = grub_register_command ("gdbstub_break", grub_cmd_gdb_break,
- /* TRANSLATORS: this refers to triggering
- a breakpoint so that the user will land
- into GDB. */
- 0, N_("Break into GDB"));
- cmd_stop = grub_register_command ("gdbstub_stop", grub_cmd_gdbstop,
- 0, N_("Stop GDB stub"));
+ cmd = grub_register_command_lockdown ("gdbstub", grub_cmd_gdbstub,
+ N_("PORT"),
+ /*
+ * TRANSLATORS: GDB stub is a small part of
+ * GDB functionality running on local host
+ * which allows remote debugger to
+ * connect to it.
+ */
+ N_("Start GDB stub on given port"));
+ cmd_break = grub_register_command_lockdown ("gdbstub_break", grub_cmd_gdb_break,
+ /*
+ * TRANSLATORS: this refers to triggering
+ * a breakpoint so that the user will land
+ * into GDB.
+ */
+ 0, N_("Break into GDB"));
+ cmd_stop = grub_register_command_lockdown ("gdbstub_stop", grub_cmd_gdbstop,
+ 0, N_("Stop GDB stub"));
}
GRUB_MOD_FINI (gdb)
--
2.26.2

View File

@ -0,0 +1,60 @@
From da75051bd36ce97b94254f17a6a94b5cbdf77d48 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 24 Feb 2021 14:44:38 +0100
Subject: [PATCH 19/46] loader/xnu: Don't allow loading extension and packages
when locked down
The shim_lock verifier validates the XNU kernels but no its extensions
and packages. Prevent these to be loaded when the GRUB is locked down.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/loader/xnu.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/grub-core/loader/xnu.c b/grub-core/loader/xnu.c
index 77d7060e1..07232d2a1 100644
--- a/grub-core/loader/xnu.c
+++ b/grub-core/loader/xnu.c
@@ -1482,20 +1482,23 @@ GRUB_MOD_INIT(xnu)
N_("Load XNU image."));
cmd_kernel64 = grub_register_command ("xnu_kernel64", grub_cmd_xnu_kernel64,
0, N_("Load 64-bit XNU image."));
- cmd_mkext = grub_register_command ("xnu_mkext", grub_cmd_xnu_mkext, 0,
- N_("Load XNU extension package."));
- cmd_kext = grub_register_command ("xnu_kext", grub_cmd_xnu_kext, 0,
- N_("Load XNU extension."));
- cmd_kextdir = grub_register_command ("xnu_kextdir", grub_cmd_xnu_kextdir,
- /* TRANSLATORS: OSBundleRequired is a
- variable name in xnu extensions
- manifests. It behaves mostly like
- GNU/Linux runlevels.
- */
- N_("DIRECTORY [OSBundleRequired]"),
- /* TRANSLATORS: There are many extensions
- in extension directory. */
- N_("Load XNU extension directory."));
+ cmd_mkext = grub_register_command_lockdown ("xnu_mkext", grub_cmd_xnu_mkext, 0,
+ N_("Load XNU extension package."));
+ cmd_kext = grub_register_command_lockdown ("xnu_kext", grub_cmd_xnu_kext, 0,
+ N_("Load XNU extension."));
+ cmd_kextdir = grub_register_command_lockdown ("xnu_kextdir", grub_cmd_xnu_kextdir,
+ /*
+ * TRANSLATORS: OSBundleRequired is
+ * a variable name in xnu extensions
+ * manifests. It behaves mostly like
+ * GNU/Linux runlevels.
+ */
+ N_("DIRECTORY [OSBundleRequired]"),
+ /*
+ * TRANSLATORS: There are many extensions
+ * in extension directory.
+ */
+ N_("Load XNU extension directory."));
cmd_ramdisk = grub_register_command ("xnu_ramdisk", grub_cmd_xnu_ramdisk, 0,
/* TRANSLATORS: ramdisk here isn't identifier. It can be translated. */
N_("Load XNU ramdisk. "
--
2.26.2

View File

@ -259,3 +259,15 @@ Patch0258: backport-0006-CVE-2020-27749.patch
Patch0259: backport-0007-CVE-2020-27749.patch Patch0259: backport-0007-CVE-2020-27749.patch
Patch0260: backport-CVE-2021-20225.patch Patch0260: backport-CVE-2021-20225.patch
Patch0261: backport-CVE-2021-20233.patch Patch0261: backport-CVE-2021-20233.patch
Patch0262: backport-0001-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0263: backport-0002-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0264: backport-0003-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0265: backport-0004-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0266: backport-0005-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0267: backport-0006-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0268: backport-0007-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0269: backport-0008-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0270: backport-0009-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0271: backport-0010-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0272: backport-0011-CVE-2020-27779-and-CVE-2020-14372.patch
Patch0273: backport-0012-CVE-2020-27779-and-CVE-2020-14372.patch

View File

@ -7,7 +7,7 @@
Name: grub2 Name: grub2
Epoch: 1 Epoch: 1
Version: 2.04 Version: 2.04
Release: 10 Release: 11
Summary: Bootloader with support for Linux, Multiboot and more Summary: Bootloader with support for Linux, Multiboot and more
License: GPLv3+ License: GPLv3+
URL: http://www.gnu.org/software/grub/ URL: http://www.gnu.org/software/grub/
@ -448,6 +448,12 @@ rm -r /boot/grub2.tmp/ || :
%{_datadir}/man/man* %{_datadir}/man/man*
%changelog %changelog
* Tue Mar 62 2021 hanhui <hanhui15@huawei.com> - 2.04-11
- Type:cves
- Id:CVE-2020-27779 CVE-2020-14372
- SUG:NA
- DESC:fix CVE-2020-27779 CVE-2020-14372
* Fri Mar 12 2021 yanglu <yanglu60@huawei.com> - 2.04-10 * Fri Mar 12 2021 yanglu <yanglu60@huawei.com> - 2.04-10
- Type:cves - Type:cves
- Id:CVE-2020-25632 CVE-2020-25647 CVE-2020-27749 CVE-2021-20225 CVE-2021-20233 - Id:CVE-2020-25632 CVE-2020-25647 CVE-2020-27749 CVE-2021-20225 CVE-2021-20233