boot/grub2: backport fixes for numerous CVEs

Grub 2.06 is affected by a number of CVEs, which have been fixed in the master branch of Grub, but are not yet part of any release (there is a 2.12-rc1 release, but nothing else between 2.06 and 2.12-rc1). So this patch backports the relevant fixes for CVE-2022-28736, CVE-2022-28735, CVE-2021-3695, CVE-2021-3696, CVE-2021-3697, CVE-2022-28733, CVE-2022-28734, CVE-2022-2601 and CVE-2022-3775. It should be noted that CVE-2021-3695, CVE-2021-3696, CVE-2021-3697 are not reported as affecting Grub by our CVE matching logic because the NVD database uses an incorrect CPE ID in those CVEs: it uses "grub" as the product instead of "grub2" like all other CVEs for grub. This issue has been reported to the NVD maintainers. This requires backporting a lot of patches, but jumping from 2.06 to 2.12-rc1 implies getting 592 commits, which is quite a lot. All Grub test cases are working fine: https://gitlab.com/tpetazzoni/buildroot/-/pipelines/984500585 https://gitlab.com/tpetazzoni/buildroot/-/pipelines/984500679 Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> [Arnout: fix check-package warning in patch 0002] Signed-off-by: Arnout Vandecappelle <arnout@mind.be>
buildroot · Aug 30, 2023 · 65c9939 · 65c9939
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diff --git a/.checkpackageignore b/.checkpackageignore
@@ -107,7 +107,6 @@ boot/at91bootstrap/0003-u-boot-relocation-fix.patch Upstream
 boot/at91dataflashboot/0001-do-not-install.patch Upstream
 boot/at91dataflashboot/0002-eabi-fixes.patch Upstream
 boot/grub2/0001-Makefile-Make-grub_fstest.pp-depend-on-config-util.h.patch Upstream
-boot/grub2/0002-grub-mkconfig-Restore-umask-for-the-grub.cfg.patch Upstream
 boot/optee-os/3.13.0/0001-core-zlib-fix-build-warning-when-_LFS64_LARGEFILE-is.patch Upstream
 boot/syslinux/0001-bios-Fix-alignment-change-with-gcc-5.patch Upstream
 boot/syslinux/0002-Disable-PIE-to-avoid-FTBFS-on-amd64.patch Upstream

diff --git a/boot/grub2/0002-grub-mkconfig-Restore-umask-for-the-grub.cfg.patch b/boot/grub2/0002-grub-mkconfig-Restore-umask-for-the-grub.cfg.patch
@@ -1,4 +1,4 @@
-From 8418defaf0902bdd8af188221ae54c5a3d6ad05d Mon Sep 17 00:00:00 2001
+From 4c1ad500e73d46c83dec369da85db39ae2fe62dd Mon Sep 17 00:00:00 2001
 From: Michael Chang <mchang@suse.com>
 Date: Fri, 3 Dec 2021 16:13:28 +0800
 Subject: [PATCH] grub-mkconfig: Restore umask for the grub.cfg
@@ -17,7 +17,7 @@ Fixes: CVE-2021-3981
 
 Signed-off-by: Michael Chang <mchang@suse.com>
 Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
-[Upstream: https://git.savannah.gnu.org/gitweb/?p=grub.git;a=commit;h=0adec29674561034771c13e446069b41ef41e4d4]
+Upstream: https://git.savannah.gnu.org/gitweb/?p=grub.git;a=commit;h=0adec29674561034771c13e446069b41ef41e4d4
 Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
 ---
  util/grub-mkconfig.in | 3 +++
@@ -39,5 +39,5 @@ index f8cbb8d7a..84f356ea4 100644
    fi
  fi
 -- 
-2.37.2
+2.41.0
 
diff --git a/boot/grub2/0003-loader-efi-chainloader-Simplify-the-loader-state.patch b/boot/grub2/0003-loader-efi-chainloader-Simplify-the-loader-state.patch
@@ -0,0 +1,126 @@
+From dfdc742bdb22be468035f96cce0be5fee23b6df5 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: 1469983ebb9674753ad333d37087fb8cb20e1dce
+[Thomas: needed to cherry-pick
+04c86e0bb7b58fc2f913f798cdb18934933e532d which fixes CVE-2022-28736]
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.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;
+-- 
+2.41.0
+
diff --git a/boot/grub2/0004-commands-boot-Add-API-to-pass-context-to-loader.patch b/boot/grub2/0004-commands-boot-Add-API-to-pass-context-to-loader.patch
@@ -0,0 +1,165 @@
+From 8b6336696d93b51703c2015eff3e2d8a02145e43 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: 14ceb3b3ff6db664649138442b6562c114dcf56e
+[Thomas: needed to backport 04c86e0bb7b58fc2f913f798cdb18934933e532d,
+which fixes CVE-2022-28736]
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.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);
+
+-- 
+2.41.0
+