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-rw-r--r--src/image/efi_image.c133
1 files changed, 115 insertions, 18 deletions
diff --git a/src/image/efi_image.c b/src/image/efi_image.c
index 467fb05a4..104753a85 100644
--- a/src/image/efi_image.c
+++ b/src/image/efi_image.c
@@ -31,6 +31,8 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <ipxe/efi/efi_wrap.h>
#include <ipxe/efi/efi_pxe.h>
#include <ipxe/efi/efi_driver.h>
+#include <ipxe/efi/efi_image.h>
+#include <ipxe/efi/efi_shim.h>
#include <ipxe/image.h>
#include <ipxe/init.h>
#include <ipxe/features.h>
@@ -109,18 +111,14 @@ efi_image_path ( struct image *image, EFI_DEVICE_PATH_PROTOCOL *parent ) {
*/
static wchar_t * efi_image_cmdline ( struct image *image ) {
wchar_t *cmdline;
- size_t len;
- len = ( strlen ( image->name ) +
- ( image->cmdline ?
- ( 1 /* " " */ + strlen ( image->cmdline ) ) : 0 ) );
- cmdline = zalloc ( ( len + 1 /* NUL */ ) * sizeof ( wchar_t ) );
- if ( ! cmdline )
+ /* Allocate and construct command line */
+ if ( efi_asprintf ( &cmdline, "%s%s%s", image->name,
+ ( image->cmdline ? " " : "" ),
+ ( image->cmdline ? image->cmdline : "" ) ) < 0 ) {
return NULL;
- efi_snprintf ( cmdline, ( len + 1 /* NUL */ ), "%s%s%s",
- image->name,
- ( image->cmdline ? " " : "" ),
- ( image->cmdline ? image->cmdline : "" ) );
+ }
+
return cmdline;
}
@@ -138,9 +136,12 @@ static int efi_image_exec ( struct image *image ) {
EFI_LOADED_IMAGE_PROTOCOL *image;
void *interface;
} loaded;
+ struct image *shim;
+ struct image *exec;
EFI_HANDLE handle;
EFI_MEMORY_TYPE type;
wchar_t *cmdline;
+ unsigned int toggle;
EFI_STATUS efirc;
int rc;
@@ -153,6 +154,21 @@ static int efi_image_exec ( struct image *image ) {
goto err_no_snpdev;
}
+ /* Use shim instead of directly executing image if applicable */
+ shim = ( efi_can_load ( image ) ?
+ NULL : find_image_tag ( &efi_shim ) );
+ exec = ( shim ? shim : image );
+ if ( shim ) {
+ DBGC ( image, "EFIIMAGE %s executing via %s\n",
+ image->name, shim->name );
+ }
+
+ /* Re-register as a hidden image to allow for access via file I/O */
+ toggle = ( ~image->flags & IMAGE_HIDDEN );
+ image->flags |= IMAGE_HIDDEN;
+ if ( ( rc = register_image ( image ) ) != 0 )
+ goto err_register_image;
+
/* Install file I/O protocols */
if ( ( rc = efi_file_install ( snpdev->handle ) ) != 0 ) {
DBGC ( image, "EFIIMAGE %s could not install file protocol: "
@@ -175,7 +191,7 @@ static int efi_image_exec ( struct image *image ) {
}
/* Create device path for image */
- path = efi_image_path ( image, snpdev->path );
+ path = efi_image_path ( exec, snpdev->path );
if ( ! path ) {
DBGC ( image, "EFIIMAGE %s could not create device path\n",
image->name );
@@ -192,11 +208,20 @@ static int efi_image_exec ( struct image *image ) {
goto err_cmdline;
}
+ /* Install shim special handling if applicable */
+ if ( shim &&
+ ( ( rc = efi_shim_install ( shim, snpdev->handle,
+ &cmdline ) ) != 0 ) ){
+ DBGC ( image, "EFIIMAGE %s could not install shim handling: "
+ "%s\n", image->name, strerror ( rc ) );
+ goto err_shim_install;
+ }
+
/* Attempt loading image */
handle = NULL;
if ( ( efirc = bs->LoadImage ( FALSE, efi_image_handle, path,
- user_to_virt ( image->data, 0 ),
- image->len, &handle ) ) != 0 ) {
+ user_to_virt ( exec->data, 0 ),
+ exec->len, &handle ) ) != 0 ) {
/* Not an EFI image */
rc = -EEFI_LOAD ( efirc );
DBGC ( image, "EFIIMAGE %s could not load: %s\n",
@@ -286,6 +311,9 @@ static int efi_image_exec ( struct image *image ) {
if ( rc != 0 )
bs->UnloadImage ( handle );
err_load_image:
+ if ( shim )
+ efi_shim_uninstall();
+ err_shim_install:
free ( cmdline );
err_cmdline:
free ( path );
@@ -296,6 +324,9 @@ static int efi_image_exec ( struct image *image ) {
err_pxe_install:
efi_file_uninstall ( snpdev->handle );
err_file_install:
+ unregister_image ( image );
+ err_register_image:
+ image->flags ^= toggle;
err_no_snpdev:
return rc;
}
@@ -346,9 +377,75 @@ static int efi_image_probe ( struct image *image ) {
return rc;
}
-/** EFI image type */
-struct image_type efi_image_type __image_type ( PROBE_NORMAL ) = {
- .name = "EFI",
- .probe = efi_image_probe,
- .exec = efi_image_exec,
+/**
+ * Probe EFI PE image
+ *
+ * @v image EFI file
+ * @ret rc Return status code
+ *
+ * The extremely broken UEFI Secure Boot model provides no way for us
+ * to unambiguously determine that a valid EFI executable image was
+ * rejected by LoadImage() because it failed signature verification.
+ * We must therefore use heuristics to guess whether not an image that
+ * was rejected by LoadImage() could still be loaded via a separate PE
+ * loader such as the UEFI shim.
+ */
+static int efi_pe_image_probe ( struct image *image ) {
+ const UINT16 magic = ( ( sizeof ( UINTN ) == sizeof ( uint32_t ) ) ?
+ EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC :
+ EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC );
+ union {
+ EFI_IMAGE_DOS_HEADER dos;
+ EFI_IMAGE_OPTIONAL_HEADER_UNION pe;
+ } u;
+
+ /* Check for existence of DOS header */
+ if ( image->len < sizeof ( u.dos ) ) {
+ DBGC ( image, "EFIIMAGE %s too short for DOS header\n",
+ image->name );
+ return -ENOEXEC;
+ }
+ copy_from_user ( &u.dos, image->data, 0, sizeof ( u.dos ) );
+ if ( u.dos.e_magic != EFI_IMAGE_DOS_SIGNATURE ) {
+ DBGC ( image, "EFIIMAGE %s missing MZ signature\n",
+ image->name );
+ return -ENOEXEC;
+ }
+
+ /* Check for existence of PE header */
+ if ( ( image->len < u.dos.e_lfanew ) ||
+ ( ( image->len - u.dos.e_lfanew ) < sizeof ( u.pe ) ) ) {
+ DBGC ( image, "EFIIMAGE %s too short for PE header\n",
+ image->name );
+ return -ENOEXEC;
+ }
+ copy_from_user ( &u.pe, image->data, u.dos.e_lfanew, sizeof ( u.pe ) );
+ if ( u.pe.Pe32.Signature != EFI_IMAGE_NT_SIGNATURE ) {
+ DBGC ( image, "EFIIMAGE %s missing PE signature\n",
+ image->name );
+ return -ENOEXEC;
+ }
+
+ /* Check PE header magic */
+ if ( u.pe.Pe32.OptionalHeader.Magic != magic ) {
+ DBGC ( image, "EFIIMAGE %s incorrect magic %04x\n",
+ image->name, u.pe.Pe32.OptionalHeader.Magic );
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
+
+/** EFI image types */
+struct image_type efi_image_type[] __image_type ( PROBE_NORMAL ) = {
+ {
+ .name = "EFI",
+ .probe = efi_image_probe,
+ .exec = efi_image_exec,
+ },
+ {
+ .name = "EFIPE",
+ .probe = efi_pe_image_probe,
+ .exec = efi_image_exec,
+ },
};
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2026-07-30 07:14:17 +0200