[PATCH 1/1] efi_loader: simplify PE consistency check

[Heinrich Schuchardt]

Knowing that at least one section header follows the optional header we
only need to check for the length of the 64bit header which is longer than
the 32bit header.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_image_loader.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index 5dd601908d..1210200314 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -635,21 +635,18 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
 		goto err;
 	}

-	/* assume sizeof(IMAGE_NT_HEADERS32) <= sizeof(IMAGE_NT_HEADERS64) */
-	if (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS32)) {
+	/*
+	 * Check if the image section header fits into the file. Knowing that at
+	 * least one section header follows we only need to check for the length
+	 * of the 64bit header which is longer than the 32bit header.
+	 */
+	if (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS64)) {
 		printf("%s: Invalid offset for Extended Header\n", __func__);
 		ret = EFI_LOAD_ERROR;
 		goto err;
 	}

 	nt = (void *) ((char *)efi + dos->e_lfanew);
-	if ((nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) &&
-	    (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS64))) {
-		printf("%s: Invalid offset for Extended Header\n", __func__);
-		ret = EFI_LOAD_ERROR;
-		goto err;
-	}
-
 	if (nt->Signature != IMAGE_NT_SIGNATURE) {
 		printf("%s: Invalid NT Signature\n", __func__);
 		ret = EFI_LOAD_ERROR;
--
2.26.2