refactor(measured-boot): mb algorithm selection
With RSS now introduced, we have 2 Measured Boot backends. Both backends
can be used in the same firmware build with potentially different hash
algorithms, so now there can be more than one hash algorithm in a build.
Therefore the logic for selecting the measured boot hash algorithm needs
to be updated and the coordination of algorithm selection added. This is
done by:
- Adding MBOOT_EL_HASH_ALG for Event Log to define the hash algorithm
to replace TPM_HASH_ALG, removing reference to TPM.
- Adding MBOOT_RSS_HASH_ALG for RSS to define the hash algorithm to
replace TPM_HASH_ALG.
- Coordinating MBOOT_EL_HASH_ALG and MBOOT_RSS_HASH_ALG to define the
Measured Boot configuration macros through defining
TF_MBEDTLS_MBOOT_USE_SHA512 to pull in SHA-512 support if either
backend requires a stronger algorithm than SHA-256.
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: I4ddf06ebdc3835beb4d1b6c7bab5a257ffc5c71a
diff --git a/include/drivers/auth/mbedtls/mbedtls_config.h b/include/drivers/auth/mbedtls/mbedtls_config.h
index 8ad6d7a..92188a2 100644
--- a/include/drivers/auth/mbedtls/mbedtls_config.h
+++ b/include/drivers/auth/mbedtls/mbedtls_config.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015-2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2015-2022, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -80,8 +80,7 @@
#define MBEDTLS_SHA512_C
#else
/* TBB uses SHA-256, what about measured boot? */
-#if defined(TF_MBEDTLS_TPM_HASH_ALG_ID) && \
- (TF_MBEDTLS_TPM_HASH_ALG_ID != TF_MBEDTLS_SHA256)
+#if defined(TF_MBEDTLS_MBOOT_USE_SHA512)
#define MBEDTLS_SHA512_C
#endif
#endif