tbbr/dualroot: Add fw_config image in chain of trust

fw_config image is authenticated using secure boot framework by
adding it into the single root and dual root chain of trust.

The COT for fw_config image looks as below:

+------------------+       +-------------------+
| ROTPK/ROTPK Hash |------>| Trusted Boot fw   |
+------------------+       | Certificate       |
                           | (Auth Image)      |
                          /+-------------------+
                         /                   |
                        /                    |
                       /                     |
                      /                      |
                     L                       v
+------------------+       +-------------------+
| fw_config hash   |------>| fw_config         |
|                  |       | (Data Image)      |
+------------------+       +-------------------+

Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I08fc8ee95c29a95bb140c807dd06e772474c7367
diff --git a/drivers/auth/dualroot/cot.c b/drivers/auth/dualroot/cot.c
index f28ddaa..31e5d65 100644
--- a/drivers/auth/dualroot/cot.c
+++ b/drivers/auth/dualroot/cot.c
@@ -16,6 +16,7 @@
  * Allocate static buffers to store the authentication parameters extracted from
  * the certificates.
  */
+static unsigned char fw_config_hash_buf[HASH_DER_LEN];
 static unsigned char tb_fw_hash_buf[HASH_DER_LEN];
 static unsigned char tb_fw_config_hash_buf[HASH_DER_LEN];
 static unsigned char hw_config_hash_buf[HASH_DER_LEN];
@@ -58,6 +59,8 @@
 		AUTH_PARAM_HASH, TRUSTED_BOOT_FW_CONFIG_HASH_OID);
 static auth_param_type_desc_t hw_config_hash = AUTH_PARAM_TYPE_DESC(
 		AUTH_PARAM_HASH, HW_CONFIG_HASH_OID);
+static auth_param_type_desc_t fw_config_hash = AUTH_PARAM_TYPE_DESC(
+		AUTH_PARAM_HASH, FW_CONFIG_HASH_OID);
 #ifdef IMAGE_BL1
 static auth_param_type_desc_t scp_bl2u_hash = AUTH_PARAM_TYPE_DESC(
 		AUTH_PARAM_HASH, SCP_FWU_CFG_HASH_OID);
@@ -165,6 +168,13 @@
 				.ptr = (void *)hw_config_hash_buf,
 				.len = (unsigned int)HASH_DER_LEN
 			}
+		},
+		[3] = {
+			.type_desc = &fw_config_hash,
+			.data = {
+				.ptr = (void *)fw_config_hash_buf,
+				.len = (unsigned int)HASH_DER_LEN
+			}
 		}
 	}
 };
@@ -218,6 +228,22 @@
 		}
 	}
 };
+
+static const auth_img_desc_t fw_config = {
+	.img_id = FW_CONFIG_ID,
+	.img_type = IMG_RAW,
+	.parent = &trusted_boot_fw_cert,
+	.img_auth_methods = (const auth_method_desc_t[AUTH_METHOD_NUM]) {
+		[0] = {
+			.type = AUTH_METHOD_HASH,
+			.param.hash = {
+				.data = &raw_data,
+				.hash = &fw_config_hash
+			}
+		}
+	}
+};
+
 #endif /* IMAGE_BL1 */
 
 #ifdef IMAGE_BL2
@@ -860,6 +886,7 @@
 	[BL2_IMAGE_ID]				=	&bl2_image,
 	[HW_CONFIG_ID]				=	&hw_config,
 	[TB_FW_CONFIG_ID]			=	&tb_fw_config,
+	[FW_CONFIG_ID]				=	&fw_config,
 	[FWU_CERT_ID]				=	&fwu_cert,
 	[SCP_BL2U_IMAGE_ID]			=	&scp_bl2u_image,
 	[BL2U_IMAGE_ID]				=	&bl2u_image,