From: Mate Kukri <mate.ku...@canonical.com>
Not reusing these handles will result in image measurements showing up
twice in the event log.
Signed-off-by: Mate Kukri <mate.ku...@canonical.com>
---
grub-core/kern/efi/sb.c | 25 ++++++++++++++++++++++++-
include/grub/efi/sb.h | 4 ++++
2 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/grub-core/kern/efi/sb.c b/grub-core/kern/efi/sb.c
index 69a75356c..04ebf02a9 100644
--- a/grub-core/kern/efi/sb.c
+++ b/grub-core/kern/efi/sb.c
@@ -36,6 +36,8 @@ static grub_guid_t shim_loader_guid =
GRUB_EFI_SHIM_IMAGE_LOADER_GUID;
static grub_efi_loader_t *shim_loader = NULL;
static grub_efi_shim_lock_protocol_t *shim_lock = NULL;
+static grub_efi_handle_t last_verified_image_handle = NULL;
+
/*
* Determine whether we're in secure boot mode.
*
@@ -181,11 +183,21 @@ shim_lock_verifier_write (void *context __attribute__
((unused)), void *buf, gru
if (shim_loader != NULL)
{
+ if (last_verified_image_handle != NULL)
+ {
+ /* Unload the previous image because ownership of the handle was
+ * not transfered to a loader, and a new image is being loaded. */
+ shim_loader->unload_image (last_verified_image_handle);
+ last_verified_image_handle = NULL;
+ }
+
if (shim_loader->load_image (false, grub_efi_image_handle, NULL, buf,
size, &image_handle) != GRUB_EFI_SUCCESS)
/* If verification fails no handle is produced */
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad shim loader
signature"));
- shim_loader->unload_image (image_handle);
+ /* Not unloading the image here because chainloader and linux
+ * might use this handle to avoid double TPM measurements. */
+ last_verified_image_handle = image_handle;
return GRUB_ERR_NONE;
}
if (shim_lock != NULL)
@@ -243,3 +255,14 @@ grub_is_using_legacy_shim_lock_protocol (void)
{
return (shim_loader == NULL && shim_lock != NULL) ? true : false;
}
+
+grub_efi_handle_t
+grub_efi_get_last_verified_image_handle (void)
+{
+ grub_efi_handle_t tmp = last_verified_image_handle;
+ /* This function is intended to act as a "transfer of ownership"
+ * of the handle. We set it to NULL so that it cannot be buggily
+ * retrieved more than once and reused for the wrong image. */
+ last_verified_image_handle = NULL;
+ return tmp;
+}
diff --git a/include/grub/efi/sb.h b/include/grub/efi/sb.h
index 4cae88376..149005ced 100644
--- a/include/grub/efi/sb.h
+++ b/include/grub/efi/sb.h
@@ -21,6 +21,7 @@
#include <grub/types.h>
#include <grub/dl.h>
+#include <grub/efi/api.h>
#define GRUB_EFI_SECUREBOOT_MODE_UNSET 0
#define GRUB_EFI_SECUREBOOT_MODE_UNKNOWN 1
@@ -34,6 +35,9 @@ EXPORT_FUNC (grub_efi_get_secureboot) (void);
extern bool
EXPORT_FUNC (grub_is_using_legacy_shim_lock_protocol) (void);
+extern grub_efi_handle_t
+EXPORT_FUNC (grub_efi_get_last_verified_image_handle) (void);
+
extern void
grub_shim_lock_verifier_setup (void);
#else
--
2.39.5
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