147 строки
4.7 KiB
Diff
147 строки
4.7 KiB
Diff
From 4a1a2c0f05839e80229fcb2516fee5067804491e 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] 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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Modified patch 04c86e0bb7b58fc2f913f798cdb18934933e532d to apply to CBL-Mariner: Merged chainloader to remove remaining globals and use grub_loader_set_ex(). Based on https://src.fedoraproject.org/rpms/grub2/blob/f0ad2aaa267a5d99b47f5c5770a55de0a702fdf0/f/0223-loader-efi-chainloader-Use-grub_loader_set_ex.patch
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Modified-by: Gary Swalling <gaswal@microsoft.com>
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---
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grub-core/loader/efi/chainloader.c | 35 +++++++++++++++---------------
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1 file changed, 18 insertions(+), 17 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 97a6a70..996787f 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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@@ -47,8 +47,6 @@ GRUB_MOD_LICENSE ("GPLv3+");
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static grub_dl_t my_mod;
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-static grub_efi_handle_t image_handle;
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-
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struct grub_secureboot_chainloader_context {
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grub_efi_physical_address_t address;
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grub_efi_uintn_t pages;
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@@ -58,11 +56,11 @@ struct grub_secureboot_chainloader_context {
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grub_ssize_t cmdline_len;
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grub_efi_handle_t dev_handle;
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};
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-static struct grub_secureboot_chainloader_context *sb_context;
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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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@@ -114,8 +112,9 @@ grub_start_image (grub_efi_handle_t handle)
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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_err_t err;
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err = grub_start_image (image_handle);
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@@ -124,7 +123,6 @@ grub_chainloader_boot (void)
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return err;
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}
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-
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static grub_err_t
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copy_file_path (grub_efi_file_path_device_path_t *fp,
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const char *str, grub_efi_uint16_t len)
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@@ -837,15 +835,16 @@ error_exit:
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}
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static grub_err_t
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-grub_secureboot_chainloader_unload (void)
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+grub_secureboot_chainloader_unload (void *context)
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{
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+ struct grub_secureboot_chainloader_context *sb_context;
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+ sb_context = (struct grub_secureboot_chainloader_context *) context;
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+
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grub_efi_free_pages (sb_context->address, sb_context->pages);
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grub_free (sb_context->file_path);
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grub_free (sb_context->cmdline);
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grub_free (sb_context);
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- sb_context = 0;
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-
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grub_dl_unref (my_mod);
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return GRUB_ERR_NONE;
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}
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@@ -894,12 +893,15 @@ grub_load_image(grub_efi_device_path_t *file_path, void *boot_image,
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}
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static grub_err_t
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-grub_secureboot_chainloader_boot (void)
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+grub_secureboot_chainloader_boot (void *context)
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{
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+ struct grub_secureboot_chainloader_context *sb_context;
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grub_efi_boot_services_t *b;
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int rc;
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grub_efi_handle_t handle = 0;
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+ sb_context = (struct grub_secureboot_chainloader_context *) context;
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+
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rc = handle_image (sb_context);
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if (rc == 0)
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{
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@@ -939,6 +941,8 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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grub_efi_char16_t *cmdline = 0;
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grub_ssize_t cmdline_len = 0;
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grub_efi_handle_t dev_handle = 0;
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+ grub_efi_handle_t image_handle = 0;
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+ struct grub_secureboot_chainloader_context *sb_context = 0;
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int rc;
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if (argc == 0)
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@@ -1111,8 +1115,8 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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grub_file_close (file);
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grub_device_close (dev);
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- grub_loader_set (grub_secureboot_chainloader_boot,
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- grub_secureboot_chainloader_unload, 0);
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+ grub_loader_set_ex (grub_secureboot_chainloader_boot,
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+ grub_secureboot_chainloader_unload, sb_context, 0);
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return 0;
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}
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else if (rc == 0)
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@@ -1126,7 +1130,7 @@ 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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}
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@@ -1148,10 +1152,7 @@ fail:
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grub_free (cmdline);
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if (image_handle != 0)
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- {
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- efi_call_1 (b->unload_image, image_handle);
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- image_handle = 0;
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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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