[PATCH v2 1/4] EFI: Populate descriptor_count value only when image_info_size is not zero

[Sughosh Ganu]

The GetImageInfo function of the Firmware Mangement Protocol(FMP) gets
called initially to query the size of the image descriptor array that
would have to be allocated. During this call, the rest of the function
arguments, specifically pointers might be passed as NULL. Do not
populate the descriptor_count value before it is known that the call
to GetImageInfo has been made with the allocated buffer for the image
descriptors.

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---

Changes since V1: None

 lib/efi_loader/efi_firmware.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
index fe4e084106..9cdefab41f 100644
--- a/lib/efi_loader/efi_firmware.c
+++ b/lib/efi_loader/efi_firmware.c
@@ -130,9 +130,6 @@ static efi_status_t efi_fill_image_desc_array(
 	struct efi_fw_image *fw_array;
 	int i;
 
-	fw_array = update_info.images;
-	*descriptor_count = num_image_type_guids;
-
 	total_size = sizeof(*image_info) * num_image_type_guids;
 
 	if (*image_info_size < total_size) {
@@ -142,6 +139,8 @@ static efi_status_t efi_fill_image_desc_array(
 	}
 	*image_info_size = total_size;
 
+	fw_array = update_info.images;
+	*descriptor_count = num_image_type_guids;
 	*descriptor_version = EFI_FIRMWARE_IMAGE_DESCRIPTOR_VERSION;
 	*descriptor_size = sizeof(*image_info);
 	*package_version = 0xffffffff; /* not supported */
-- 
2.25.1