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[SECURITY PATCH 01/30] loader/efi/chainloader: Simplify the loader state
From: |
Daniel Kiper |
Subject: |
[SECURITY PATCH 01/30] loader/efi/chainloader: Simplify the loader state |
Date: |
Tue, 7 Jun 2022 19:01:10 +0200 |
From: Chris Coulson <chris.coulson@canonical.com>
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>
---
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;
--
2.11.0
- [SECURITY PATCH 00/30] Multiple GRUB2 vulnerabilities - 2022/06/07 round, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 02/30] commands/boot: Add API to pass context to loader, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 01/30] loader/efi/chainloader: Simplify the loader state,
Daniel Kiper <=
- [SECURITY PATCH 04/30] kern/efi/sb: Reject non-kernel files in the shim_lock verifier, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 13/30] video/readers/jpeg: Refuse to handle multiple start of streams, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 11/30] video/readers/jpeg: Abort sooner if a read operation fails, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 16/30] net/ip: Do IP fragment maths safely, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 05/30] kern/file: Do not leak device_name on error in grub_file_open(), Daniel Kiper, 2022/06/07
- [SECURITY PATCH 26/30] fs/f2fs: Do not read past the end of nat bitmap, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 12/30] video/readers/jpeg: Do not reallocate a given huff table, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 03/30] loader/efi/chainloader: Use grub_loader_set_ex(), Daniel Kiper, 2022/06/07
- [SECURITY PATCH 10/30] video/readers/png: Sanity check some huffman codes, Daniel Kiper, 2022/06/07
- [SECURITY PATCH 09/30] video/readers/png: Avoid heap OOB R/W inserting huff table items, Daniel Kiper, 2022/06/07