From: Andrei Borzenkov Subject: [PATCH] efi: fix off-by-one error in chainloader filepath EFI File Path Media Device Path is defined as NULL terminated string; but chainloader built file paths without final NULL. This caused error with Secure Boot and Linux Foundation PreLoader. Apparently firmware failed verification with EFI_INVALID_PARAMETER which is considered fatal error by PreLoader. Fix debug print of device path while on it. Reported and tested by Giovanni Santini --- grub-core/loader/efi/chainloader.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c index 522a716..3fc03a1 100644 --- a/grub-core/loader/efi/chainloader.c +++ b/grub-core/loader/efi/chainloader.c @@ -122,6 +122,8 @@ copy_file_path (grub_efi_file_path_device_path_t *fp, if (*p == '/') *p = '\\'; + /* File Path is NULL terminated */ + fp->path_name[size++] = '\0'; fp->header.length = size * sizeof (grub_efi_char16_t) + sizeof (*fp); } @@ -156,8 +158,10 @@ make_file_path (grub_efi_device_path_t *dp, const char *filename) d = GRUB_EFI_NEXT_DEVICE_PATH (d); } + /* File Path is NULL terminated. Allocate space for 2 extra characters */ + /* FIXME why we split path in two components? */ file_path = grub_malloc (size - + ((grub_strlen (dir_start) + 1) + + ((grub_strlen (dir_start) + 2) * GRUB_MAX_UTF16_PER_UTF8 * sizeof (grub_efi_char16_t)) + sizeof (grub_efi_file_path_device_path_t) * 2); @@ -169,7 +173,7 @@ make_file_path (grub_efi_device_path_t *dp, const char *filename) /* Fill the file path for the directory. */ d = (grub_efi_device_path_t *) ((char *) file_path + ((char *) d - (char *) dp)); - grub_efi_print_device_path (d); + grub_efi_print_device_path (dp); copy_file_path ((grub_efi_file_path_device_path_t *) d, dir_start, dir_end - dir_start); -- tg: (a3e9da0..) u/efi-chainloader-filepath (depends on: master)