Merge tag 'efi-fixes-for-v6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fix from Ard Biesheuvel:
 "This fixes an oversight on my part in the recent EFI stub rework for
  x86, which is needed to get Linux/x86 distro builds signed again for
  secure boot by Microsoft. For this reason, most of this work is being
  backported to v6.1, which is therefore also affected by this
  regression.

   - Explicitly wipe BSS in the native EFI entrypoint, so that globals
     shared with the legacy decompressor are zero-initialized correctly"

* tag 'efi-fixes-for-v6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  x86/efistub: Clear decompressor BSS in native EFI entrypoint

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 4f448d4df7b8..57888614e90f 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -21,6 +21,8 @@
 #include "efistub.h"
 #include "x86-stub.h"
 
+extern char _bss[], _ebss[];
+
 const efi_system_table_t *efi_system_table;
 const efi_dxe_services_table_t *efi_dxe_table;
 static efi_loaded_image_t *image = NULL;
@@ -474,6 +476,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 	efi_status_t status;
 	char *cmdline_ptr;
 
+	memset(_bss, 0, _ebss - _bss);
+
 	efi_system_table = sys_table_arg;
 
 	/* Check if we were booted by the EFI firmware */
@@ -970,8 +974,6 @@ fail:
 void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
 			struct boot_params *boot_params)
 {
-	extern char _bss[], _ebss[];
-
 	memset(_bss, 0, _ebss - _bss);
 	efi_stub_entry(handle, sys_table_arg, boot_params);
 }