Squashed commit upgrading to mbedtls-2.16.5

Squash merging branch import/mbedtls-2.16.5

058aefb2bfa4 ("core: mbedtls: use SHA-256 crypto accelerated routines")
bcef9baed8f1 ("core: mbedtls: use SHA-1 crypto accelerated routines")
c9359f31db12 ("core: mbedtls: use AES crypto accelerated routines")
0e6c1e2642c7 ("core: merge tee_*_get_digest_size() into a single function")
0cb3c28a2f4d ("libmbedtls: mbedtls_mpi_exp_mod(): optimize mempool usage")
5abf0e6ab72e ("libmbedtls: mbedtls_mpi_exp_mod(): reduce stack usage")
2ccc08ac7fef ("libmbedtls: preserve mempool usage on reinit")
cd2a24648569 ("libmbedtls: mbedtls_mpi_exp_mod() initialize W")
7727182ecb56 ("libmbedtls: fix no CRT issue")
120737075dcf ("libmbedtls: add interfaces in mbedtls for context memory operation")
1126250b3af8 ("libmbedtls: add missing source file chachapoly.c")
23972e9f1c98 ("libmedtls: mpi_miller_rabin: increase count limit")
1fcbc05b3cd2 ("libmbedtls: add mbedtls_mpi_init_mempool()")
66e03f068078 ("libmbedtls: make mbedtls_mpi_mont*() available")
d07e0ce56236 ("libmbedtls: refine mbedtls license header")
491ee2cd0ff4 ("mbedtls: configure mbedtls to reach for config")
9b6cee685d9a ("mbedtls: remove default include/mbedtls/config.h")
84f7467a0a91 ("Import mbedtls-2.16.5")

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/ecdh.c b/lib/libmbedtls/mbedtls/library/ecdh.c
index 9f644aa..c569016 100644
--- a/lib/libmbedtls/mbedtls/library/ecdh.c
+++ b/lib/libmbedtls/mbedtls/library/ecdh.c
@@ -49,6 +49,16 @@
 typedef mbedtls_ecdh_context mbedtls_ecdh_context_mbed;
 #endif
 
+static mbedtls_ecp_group_id mbedtls_ecdh_grp_id(
+    const mbedtls_ecdh_context *ctx )
+{
+#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
+    return( ctx->grp.id );
+#else
+    return( ctx->grp_id );
+#endif
+}
+
 #if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
 /*
  * Generate public key (restartable version)
@@ -442,8 +452,21 @@
     ECDH_VALIDATE_RET( side == MBEDTLS_ECDH_OURS ||
                        side == MBEDTLS_ECDH_THEIRS );
 
-    if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 )
-        return( ret );
+    if( mbedtls_ecdh_grp_id( ctx ) == MBEDTLS_ECP_DP_NONE )
+    {
+        /* This is the first call to get_params(). Set up the context
+         * for use with the group. */
+        if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 )
+            return( ret );
+    }
+    else
+    {
+        /* This is not the first call to get_params(). Check that the
+         * current key's group is the same as the context's, which was set
+         * from the first key's group. */
+        if( mbedtls_ecdh_grp_id( ctx ) != key->grp.id )
+            return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+    }
 
 #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
     return( ecdh_get_params_internal( ctx, key, side ) );