| 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 |
| |