Add test case for ecdh_get_params with mismatching group

Add a test case for doing an ECDH calculation by calling
mbedtls_ecdh_get_params on both keys, with keys belonging to
different groups. This should fail, but currently passes.

Author: gilles-peskine-arm

tests/suites/test_suite_ecdh.data

@@ -87,3 +87,11 @@ ecdh_exchange_calc_secret:MBEDTLS_ECP_DP_SECP256R1:"c6ef9c5d78ae012a011164acb397
 ECDH calc_secret: theirs first, SECP256R1 (RFC 5903)
 depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
 ecdh_exchange_calc_secret:MBEDTLS_ECP_DP_SECP256R1:"c6ef9c5d78ae012a011164acb397ce2088685d8f06bf9be0b283ab46476bee53":"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":1:"d6840f6b42f6edafd13116e0e12565202fef8e9ece7dce03812464d04b9442de"
+
+ECDH get_params with mismatched groups: our BP256R1, their SECP256R1
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_BP256R1_ENABLED
+ecdh_exchange_get_params_fail:MBEDTLS_ECP_DP_BP256R1:"1234567812345678123456781234567812345678123456781234567812345678":MBEDTLS_ECP_DP_SECP256R1:"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":0:MBEDTLS_ERR_ECP_BAD_INPUT_DATA
+
+ECDH get_params with mismatched groups: their SECP256R1, our BP256R1
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_ECP_DP_BP256R1_ENABLED
+ecdh_exchange_get_params_fail:MBEDTLS_ECP_DP_BP256R1:"1234567812345678123456781234567812345678123456781234567812345678":MBEDTLS_ECP_DP_SECP256R1:"04dad0b65394221cf9b051e1feca5787d098dfe637fc90b9ef945d0c37725811805271a0461cdb8252d61f1c456fa3e59ab1f45b33accf5f58389e0577b8990bb3":1:MBEDTLS_ERR_ECP_BAD_INPUT_DATA

tests/suites/test_suite_ecdh.function

@@ -557,3 +557,50 @@ exit:
     mbedtls_ecp_keypair_free( &their_key );
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void ecdh_exchange_get_params_fail( int our_grp_id,
+                                    data_t *our_private_key,
+                                    int their_grp_id,
+                                    data_t *their_point,
+                                    int ours_first,
+                                    int expected_ret )
+{
+    rnd_pseudo_info rnd_info;
+    mbedtls_ecp_keypair our_key;
+    mbedtls_ecp_keypair their_key;
+    mbedtls_ecdh_context ecdh;
+
+    memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
+    mbedtls_ecdh_init( &ecdh );
+    mbedtls_ecp_keypair_init( &our_key );
+    mbedtls_ecp_keypair_init( &their_key );
+
+    if( ! load_private_key( our_grp_id, our_private_key, &our_key, &rnd_info ) )
+        goto exit;
+    if( ! load_public_key( their_grp_id, their_point, &their_key ) )
+        goto exit;
+
+    if( ours_first )
+    {
+        TEST_ASSERT( mbedtls_ecdh_get_params(
+                         &ecdh, &our_key, MBEDTLS_ECDH_OURS ) == 0 );
+        TEST_ASSERT( mbedtls_ecdh_get_params(
+                         &ecdh, &their_key, MBEDTLS_ECDH_THEIRS ) ==
+                     expected_ret );
+    }
+    else
+    {
+        TEST_ASSERT( mbedtls_ecdh_get_params(
+                         &ecdh, &their_key, MBEDTLS_ECDH_THEIRS ) == 0 );
+        TEST_ASSERT( mbedtls_ecdh_get_params(
+                         &ecdh, &our_key, MBEDTLS_ECDH_OURS ) ==
+                     expected_ret );
+    }
+
+exit:
+    mbedtls_ecdh_free( &ecdh );
+    mbedtls_ecp_keypair_free( &our_key );
+    mbedtls_ecp_keypair_free( &their_key );
+}
+/* END_CASE */