grub: backport patches to fix CVE-2022-28736

(From OE-Core rev: 278e1a0f679be813553b014544314041502a586a)

Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Xiangyu Chen 2022-12-07 11:42:54 +08:00 committed by Richard Purdie
parent cc1c4506ba
commit 7967e2aa0c
4 changed files with 386 additions and 0 deletions

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@ -0,0 +1,86 @@
From 04c86e0bb7b58fc2f913f798cdb18934933e532d Mon Sep 17 00:00:00 2001
From: Chris Coulson <chris.coulson@canonical.com>
Date: Tue, 5 Apr 2022 11:48:58 +0100
Subject: [PATCH] loader/efi/chainloader: Use grub_loader_set_ex()
This ports the EFI chainloader to use grub_loader_set_ex() in order to fix
a use-after-free bug that occurs when grub_cmd_chainloader() is executed
more than once before a boot attempt is performed.
Fixes: CVE-2022-28736
Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream-Status: Backport
CVE: CVE-2022-28736
Reference to upstream patch:
https://git.savannah.gnu.org/cgit/grub.git/commit/?id=04c86e0bb7b58fc2f913f798cdb18934933e532d
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
---
grub-core/loader/efi/chainloader.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
index d1602c89b..7557eb269 100644
--- a/grub-core/loader/efi/chainloader.c
+++ b/grub-core/loader/efi/chainloader.c
@@ -44,11 +44,10 @@ GRUB_MOD_LICENSE ("GPLv3+");
static grub_dl_t my_mod;
-static grub_efi_handle_t image_handle;
-
static grub_err_t
-grub_chainloader_unload (void)
+grub_chainloader_unload (void *context)
{
+ grub_efi_handle_t image_handle = (grub_efi_handle_t) context;
grub_efi_loaded_image_t *loaded_image;
grub_efi_boot_services_t *b;
@@ -64,8 +63,9 @@ grub_chainloader_unload (void)
}
static grub_err_t
-grub_chainloader_boot (void)
+grub_chainloader_boot (void *context)
{
+ grub_efi_handle_t image_handle = (grub_efi_handle_t) context;
grub_efi_boot_services_t *b;
grub_efi_status_t status;
grub_efi_uintn_t exit_data_size;
@@ -225,6 +225,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
grub_efi_physical_address_t address = 0;
grub_efi_uintn_t pages = 0;
grub_efi_char16_t *cmdline = NULL;
+ grub_efi_handle_t image_handle = NULL;
if (argc == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
@@ -405,7 +406,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
efi_call_2 (b->free_pages, address, pages);
grub_free (file_path);
- grub_loader_set (grub_chainloader_boot, grub_chainloader_unload, 0);
+ grub_loader_set_ex (grub_chainloader_boot, grub_chainloader_unload, image_handle, 0);
return 0;
fail:
@@ -423,10 +424,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
efi_call_2 (b->free_pages, address, pages);
if (image_handle != NULL)
- {
- efi_call_1 (b->unload_image, image_handle);
- image_handle = NULL;
- }
+ efi_call_1 (b->unload_image, image_handle);
grub_dl_unref (my_mod);
--
2.34.1

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@ -0,0 +1,168 @@
From 14ceb3b3ff6db664649138442b6562c114dcf56e Mon Sep 17 00:00:00 2001
From: Chris Coulson <chris.coulson@canonical.com>
Date: Tue, 5 Apr 2022 10:58:28 +0100
Subject: [PATCH] commands/boot: Add API to pass context to loader
Loaders rely on global variables for saving context which is consumed
in the boot hook and freed in the unload hook. In the case where a loader
command is executed twice, calling grub_loader_set() a second time executes
the unload hook, but in some cases this runs when the loader's global
context has already been updated, resulting in the updated context being
freed and potential use-after-free bugs when the boot hook is subsequently
called.
This adds a new API, grub_loader_set_ex(), which allows a loader to specify
context that is passed to its boot and unload hooks. This is an alternative
to requiring that loaders call grub_loader_unset() before mutating their
global context.
Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream-Status: Backport
Reference to upstream patch:
https://git.savannah.gnu.org/cgit/grub.git/commit/?id=14ceb3b3ff6db664649138442b6562c114dcf56e
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
---
grub-core/commands/boot.c | 66 ++++++++++++++++++++++++++++++++++-----
include/grub/loader.h | 5 +++
2 files changed, 63 insertions(+), 8 deletions(-)
diff --git a/grub-core/commands/boot.c b/grub-core/commands/boot.c
index bbca81e94..61514788e 100644
--- a/grub-core/commands/boot.c
+++ b/grub-core/commands/boot.c
@@ -27,10 +27,20 @@
GRUB_MOD_LICENSE ("GPLv3+");
-static grub_err_t (*grub_loader_boot_func) (void);
-static grub_err_t (*grub_loader_unload_func) (void);
+static grub_err_t (*grub_loader_boot_func) (void *context);
+static grub_err_t (*grub_loader_unload_func) (void *context);
+static void *grub_loader_context;
static int grub_loader_flags;
+struct grub_simple_loader_hooks
+{
+ grub_err_t (*boot) (void);
+ grub_err_t (*unload) (void);
+};
+
+/* Don't heap allocate this to avoid making grub_loader_set() fallible. */
+static struct grub_simple_loader_hooks simple_loader_hooks;
+
struct grub_preboot
{
grub_err_t (*preboot_func) (int);
@@ -44,6 +54,29 @@ static int grub_loader_loaded;
static struct grub_preboot *preboots_head = 0,
*preboots_tail = 0;
+static grub_err_t
+grub_simple_boot_hook (void *context)
+{
+ struct grub_simple_loader_hooks *hooks;
+
+ hooks = (struct grub_simple_loader_hooks *) context;
+ return hooks->boot ();
+}
+
+static grub_err_t
+grub_simple_unload_hook (void *context)
+{
+ struct grub_simple_loader_hooks *hooks;
+ grub_err_t ret;
+
+ hooks = (struct grub_simple_loader_hooks *) context;
+
+ ret = hooks->unload ();
+ grub_memset (hooks, 0, sizeof (*hooks));
+
+ return ret;
+}
+
int
grub_loader_is_loaded (void)
{
@@ -110,28 +143,45 @@ grub_loader_unregister_preboot_hook (struct grub_preboot *hnd)
}
void
-grub_loader_set (grub_err_t (*boot) (void),
- grub_err_t (*unload) (void),
- int flags)
+grub_loader_set_ex (grub_err_t (*boot) (void *context),
+ grub_err_t (*unload) (void *context),
+ void *context,
+ int flags)
{
if (grub_loader_loaded && grub_loader_unload_func)
- grub_loader_unload_func ();
+ grub_loader_unload_func (grub_loader_context);
grub_loader_boot_func = boot;
grub_loader_unload_func = unload;
+ grub_loader_context = context;
grub_loader_flags = flags;
grub_loader_loaded = 1;
}
+void
+grub_loader_set (grub_err_t (*boot) (void),
+ grub_err_t (*unload) (void),
+ int flags)
+{
+ grub_loader_set_ex (grub_simple_boot_hook,
+ grub_simple_unload_hook,
+ &simple_loader_hooks,
+ flags);
+
+ simple_loader_hooks.boot = boot;
+ simple_loader_hooks.unload = unload;
+}
+
void
grub_loader_unset(void)
{
if (grub_loader_loaded && grub_loader_unload_func)
- grub_loader_unload_func ();
+ grub_loader_unload_func (grub_loader_context);
grub_loader_boot_func = 0;
grub_loader_unload_func = 0;
+ grub_loader_context = 0;
grub_loader_loaded = 0;
}
@@ -158,7 +208,7 @@ grub_loader_boot (void)
return err;
}
}
- err = (grub_loader_boot_func) ();
+ err = (grub_loader_boot_func) (grub_loader_context);
for (cur = preboots_tail; cur; cur = cur->prev)
if (! err)
diff --git a/include/grub/loader.h b/include/grub/loader.h
index b20864282..97f231054 100644
--- a/include/grub/loader.h
+++ b/include/grub/loader.h
@@ -40,6 +40,11 @@ void EXPORT_FUNC (grub_loader_set) (grub_err_t (*boot) (void),
grub_err_t (*unload) (void),
int flags);
+void EXPORT_FUNC (grub_loader_set_ex) (grub_err_t (*boot) (void *context),
+ grub_err_t (*unload) (void *context),
+ void *context,
+ int flags);
+
/* Unset current loader, if any. */
void EXPORT_FUNC (grub_loader_unset) (void);
--
2.34.1

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@ -0,0 +1,129 @@
From 1469983ebb9674753ad333d37087fb8cb20e1dce Mon Sep 17 00:00:00 2001
From: Chris Coulson <chris.coulson@canonical.com>
Date: Tue, 5 Apr 2022 10:02:04 +0100
Subject: [PATCH] loader/efi/chainloader: Simplify the loader state
The chainloader command retains the source buffer and device path passed
to LoadImage(), requiring the unload hook passed to grub_loader_set() to
free them. It isn't required to retain this state though - they aren't
required by StartImage() or anything else in the boot hook, so clean them
up before grub_cmd_chainloader() finishes.
Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream-Status: Backport
Reference to upstream patch:
https://git.savannah.gnu.org/cgit/grub.git/commit/?id=1469983ebb9674753ad333d37087fb8cb20e1dce
Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com>
---
grub-core/loader/efi/chainloader.c | 38 +++++++++++++++++-------------
1 file changed, 21 insertions(+), 17 deletions(-)
diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
index 2bd80f4db..d1602c89b 100644
--- a/grub-core/loader/efi/chainloader.c
+++ b/grub-core/loader/efi/chainloader.c
@@ -44,25 +44,20 @@ GRUB_MOD_LICENSE ("GPLv3+");
static grub_dl_t my_mod;
-static grub_efi_physical_address_t address;
-static grub_efi_uintn_t pages;
-static grub_efi_device_path_t *file_path;
static grub_efi_handle_t image_handle;
-static grub_efi_char16_t *cmdline;
static grub_err_t
grub_chainloader_unload (void)
{
+ grub_efi_loaded_image_t *loaded_image;
grub_efi_boot_services_t *b;
+ loaded_image = grub_efi_get_loaded_image (image_handle);
+ if (loaded_image != NULL)
+ grub_free (loaded_image->load_options);
+
b = grub_efi_system_table->boot_services;
efi_call_1 (b->unload_image, image_handle);
- efi_call_2 (b->free_pages, address, pages);
-
- grub_free (file_path);
- grub_free (cmdline);
- cmdline = 0;
- file_path = 0;
grub_dl_unref (my_mod);
return GRUB_ERR_NONE;
@@ -140,7 +135,7 @@ make_file_path (grub_efi_device_path_t *dp, const char *filename)
char *dir_start;
char *dir_end;
grub_size_t size;
- grub_efi_device_path_t *d;
+ grub_efi_device_path_t *d, *file_path;
dir_start = grub_strchr (filename, ')');
if (! dir_start)
@@ -222,11 +217,14 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
grub_efi_status_t status;
grub_efi_boot_services_t *b;
grub_device_t dev = 0;
- grub_efi_device_path_t *dp = 0;
+ grub_efi_device_path_t *dp = NULL, *file_path = NULL;
grub_efi_loaded_image_t *loaded_image;
char *filename;
void *boot_image = 0;
grub_efi_handle_t dev_handle = 0;
+ grub_efi_physical_address_t address = 0;
+ grub_efi_uintn_t pages = 0;
+ grub_efi_char16_t *cmdline = NULL;
if (argc == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
@@ -234,11 +232,6 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
grub_dl_ref (my_mod);
- /* Initialize some global variables. */
- address = 0;
- image_handle = 0;
- file_path = 0;
-
b = grub_efi_system_table->boot_services;
file = grub_file_open (filename, GRUB_FILE_TYPE_EFI_CHAINLOADED_IMAGE);
@@ -408,6 +401,10 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
grub_file_close (file);
grub_device_close (dev);
+ /* We're finished with the source image buffer and file path now. */
+ efi_call_2 (b->free_pages, address, pages);
+ grub_free (file_path);
+
grub_loader_set (grub_chainloader_boot, grub_chainloader_unload, 0);
return 0;
@@ -419,11 +416,18 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
if (file)
grub_file_close (file);
+ grub_free (cmdline);
grub_free (file_path);
if (address)
efi_call_2 (b->free_pages, address, pages);
+ if (image_handle != NULL)
+ {
+ efi_call_1 (b->unload_image, image_handle);
+ image_handle = NULL;
+ }
+
grub_dl_unref (my_mod);
return grub_errno;
--
2.34.1

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@ -34,6 +34,9 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
file://CVE-2022-28735-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch \
file://0001-configure-Remove-obsoleted-malign-jumps-loops-functi.patch \
file://0002-configure-Check-for-falign-jumps-1-beside-falign-loo.patch \
file://loader-efi-chainloader-Simplify-the-loader-state.patch \
file://commands-boot-Add-API-to-pass-context-to-loader.patch \
file://CVE-2022-28736-loader-efi-chainloader-Use-grub_loader_set_ex.patch\
"
SRC_URI[sha256sum] = "23b64b4c741569f9426ed2e3d0e6780796fca081bee4c99f62aa3f53ae803f5f"