Support larger RSA key sizes when using MBEDTLS
Previously, TF-A could not support large RSA key sizes as the
configuration options passed to MBEDTLS prevented storing and performing
calculations with the larger, higher-precision numbers required. With
these changes to the arguments passed to MBEDTLS, TF-A now supports
using 3072 (3K) and 4096 (4K) keys in certificates.
Change-Id: Ib73a6773145d2faa25c28d04f9a42e86f2fd555f
Signed-off-by: Justin Chadwell <justin.chadwell@arm.com>
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
index 63e65bd..f34d3d0 100644
--- a/drivers/auth/mbedtls/mbedtls_common.mk
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -1,5 +1,5 @@
#
-# Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
#
@@ -59,6 +59,16 @@
endif
endif
+ifeq (${TF_MBEDTLS_KEY_SIZE},)
+ ifneq ($(findstring rsa,${TF_MBEDTLS_KEY_ALG}),)
+ ifeq (${KEY_SIZE},)
+ TF_MBEDTLS_KEY_SIZE := 2048
+ else
+ TF_MBEDTLS_KEY_SIZE := ${KEY_SIZE}
+ endif
+ endif
+endif
+
ifeq (${HASH_ALG}, sha384)
TF_MBEDTLS_HASH_ALG_ID := TF_MBEDTLS_SHA384
else ifeq (${HASH_ALG}, sha512)
@@ -79,6 +89,7 @@
# Needs to be set to drive mbed TLS configuration correctly
$(eval $(call add_define,TF_MBEDTLS_KEY_ALG_ID))
+$(eval $(call add_define,TF_MBEDTLS_KEY_SIZE))
$(eval $(call add_define,TF_MBEDTLS_HASH_ALG_ID))
diff --git a/drivers/auth/tbbr/tbbr_cot.c b/drivers/auth/tbbr/tbbr_cot.c
index da3631b..6dd4ae2 100644
--- a/drivers/auth/tbbr/tbbr_cot.c
+++ b/drivers/auth/tbbr/tbbr_cot.c
@@ -7,6 +7,7 @@
#include <stddef.h>
#include <platform_def.h>
+#include <drivers/auth/mbedtls/mbedtls_config.h>
#include <drivers/auth/auth_mod.h>
#if USE_TBBR_DEFS
@@ -19,7 +20,22 @@
/*
* Maximum key and hash sizes (in DER format)
*/
+#if TF_MBEDTLS_USE_RSA
+#if TF_MBEDTLS_KEY_SIZE == 1024
+#define PK_DER_LEN 162
+#elif TF_MBEDTLS_KEY_SIZE == 2048
#define PK_DER_LEN 294
+#elif TF_MBEDTLS_KEY_SIZE == 3072
+#define PK_DER_LEN 422
+#elif TF_MBEDTLS_KEY_SIZE == 4096
+#define PK_DER_LEN 550
+#else
+#error "Invalid value for TF_MBEDTLS_KEY_SIZE"
+#endif
+#else
+#define PK_DER_LEN 294
+#endif
+
#define HASH_DER_LEN 83
/*