83 lines
2.7 KiB
Diff
83 lines
2.7 KiB
Diff
From e0cc6a601865a72cfe316f2cbbaaefcdd2ad8c69 Mon Sep 17 00:00:00 2001
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From: Chris Coulson <chris.coulson@canonical.com>
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Date: Tue, 5 Apr 2022 11:48:58 +0100
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Subject: [PATCH 04/32] loader/efi/chainloader: Use grub_loader_set_ex()
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This ports the EFI chainloader to use grub_loader_set_ex() in order to fix
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a use-after-free bug that occurs when grub_cmd_chainloader() is executed
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more than once before a boot attempt is performed.
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Fixes: CVE-2022-28736
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Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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grub-core/loader/efi/chainloader.c | 15 +++++++--------
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1 file changed, 7 insertions(+), 8 deletions(-)
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diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
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index 1ec09a166c..b3e1e89302 100644
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--- a/grub-core/loader/efi/chainloader.c
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+++ b/grub-core/loader/efi/chainloader.c
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@@ -54,7 +54,6 @@ GRUB_MOD_LICENSE ("GPLv3+");
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static grub_dl_t my_mod;
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static grub_ssize_t fsize;
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-static grub_efi_handle_t image_handle;
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static grub_ssize_t cmdline_len;
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static grub_efi_handle_t dev_handle;
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@@ -64,8 +63,9 @@ static grub_efi_status_t (*entry_point) (grub_efi_handle_t image_handle, grub_e
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#endif
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static grub_err_t
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-grub_chainloader_unload (void)
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+grub_chainloader_unload (void *context)
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{
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+ grub_efi_handle_t image_handle = (grub_efi_handle_t) context;
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grub_efi_loaded_image_t *loaded_image;
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grub_efi_boot_services_t *b;
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@@ -83,8 +83,9 @@ grub_chainloader_unload (void)
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}
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static grub_err_t
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-grub_chainloader_boot (void)
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+grub_chainloader_boot (void *context)
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{
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+ grub_efi_handle_t image_handle = (grub_efi_handle_t) context;
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grub_efi_boot_services_t *b;
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grub_efi_status_t status;
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grub_efi_uintn_t exit_data_size;
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@@ -644,6 +645,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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grub_efi_physical_address_t address = 0;
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grub_efi_uintn_t pages = 0;
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grub_efi_char16_t *cmdline = NULL;
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+ grub_efi_handle_t image_handle = NULL;
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if (argc == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
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@@ -856,7 +858,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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efi_call_2 (b->free_pages, address, pages);
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grub_free (file_path);
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- grub_loader_set (grub_chainloader_boot, grub_chainloader_unload, 0);
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+ grub_loader_set_ex (grub_chainloader_boot, grub_chainloader_unload, image_handle, 0);
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return 0;
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fail:
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@@ -874,10 +876,7 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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efi_call_2 (b->free_pages, address, pages);
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if (image_handle != NULL)
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- {
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- efi_call_1 (b->unload_image, image_handle);
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- image_handle = NULL;
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- }
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+ efi_call_1 (b->unload_image, image_handle);
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grub_dl_unref (my_mod);
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--
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2.34.1
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