Add early return test + fake implementation
diff --git a/library/ecp.c b/library/ecp.c
index 1358a3f..987739f 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -99,6 +99,22 @@
{
ecp_max_ops = max_ops;
}
+
+/*
+ * Saved context type for restarting operations.
+ *
+ * XXX: this is a temporary place for the definition
+ */
+typedef struct {
+ unsigned char fake_it; /* for tests: should we fake early return? */
+} ecp_restart_context;
+
+/*
+ * Saved context fro restarting operations.
+ *
+ * XXX: temporary place for the allocation
+ */
+static ecp_restart_context ecp_restart;
#endif /* MBEDTLS_ECP_EARLY_RETURN */
#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \
@@ -1376,6 +1392,11 @@
mbedtls_ecp_point *T;
mbedtls_mpi M, mm;
+#if defined(MBEDTLS_ECP_EARLY_RETURN)
+ if( ecp_restart.fake_it++ != 0 && ecp_max_ops != 0 )
+ return( MBEDTLS_ERR_ECP_IN_PROGRESS );
+#endif
+
mbedtls_mpi_init( &M );
mbedtls_mpi_init( &mm );
diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index a43e7d7..f96be5a 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -344,3 +344,11 @@
ECP selftest
ecp_selftest:
+
+ECP early return secp256r1 restart disabled
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_test_vect_restart:MBEDTLS_ECP_DP_SECP256R1:"814264145F2F56F2E96A8E337A1284993FAF432A5ABCE59E867B7291D507A3AF":"2AF502F3BE8952F2C9B5A8D4160D09E97165BE50BC42AE4A5E8D3B4BA83AEB15":"EB0FAF4CA986C4D38681A0F9872D79D56795BD4BFF6E6DE3C0F5015ECE5EFD85":"2CE1788EC197E096DB95A200CC0AB26A19CE6BCCAD562B8EEE1B593761CF7F41":"DD0F5396219D1EA393310412D19A08F1F5811E9DC8EC8EEA7F80D21C820C2788":"0357DCCD4C804D0D8D33AA42B848834AA5605F9AB0D37239A115BBB647936F50":0:0:0
+
+ECP early return secp256r1 restart enabled
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_test_vect_restart:MBEDTLS_ECP_DP_SECP256R1:"814264145F2F56F2E96A8E337A1284993FAF432A5ABCE59E867B7291D507A3AF":"2AF502F3BE8952F2C9B5A8D4160D09E97165BE50BC42AE4A5E8D3B4BA83AEB15":"EB0FAF4CA986C4D38681A0F9872D79D56795BD4BFF6E6DE3C0F5015ECE5EFD85":"2CE1788EC197E096DB95A200CC0AB26A19CE6BCCAD562B8EEE1B593761CF7F41":"DD0F5396219D1EA393310412D19A08F1F5811E9DC8EC8EEA7F80D21C820C2788":"0357DCCD4C804D0D8D33AA42B848834AA5605F9AB0D37239A115BBB647936F50":1:1:5000
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 99780c0..c8daef9 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -51,6 +51,107 @@
}
/* END_CASE */
+/* BEGIN_CASE depends_on:MBEDTLS_ECP_EARLY_RETURN */
+void ecp_test_vect_restart( int id,
+ char *dA_str, char *xA_str, char *yA_str,
+ char *dB_str, char *xZ_str, char *yZ_str,
+ int max_ops, int min_restarts, int max_restarts )
+{
+ /*
+ * Test for early restart. Based on test vectors like ecp_test_vect(),
+ * but for the sake of simplicity only does half of each side. It's
+ * important to test both base point and random point, though, as memory
+ * management is different in each case.
+ *
+ * Don't try using too precise bounds for restarts as the exact number
+ * will depend on settings such as MBEDTLS_ECP_FIXED_POINT_OPTIM and
+ * MBEDTLS_ECP_WINDOW_SIZE, as well as implementation details that may
+ * change in the future. A factor 2 is a minimum safety margin.
+ *
+ * For reference, with mbed TLS 2.4 and default settings, for P-256:
+ * - Random point mult: ~3600M
+ * - Cold base point mult: ~3600M
+ * - Hot base point mult: ~1200M
+ * With MBEDTLS_ECP_WINDOW_SIZE set to 2 (minimum):
+ * - Random point mult: ~4200M
+ */
+ mbedtls_ecp_group grp;
+ mbedtls_ecp_point R;
+ mbedtls_mpi dA, xA, yA, dB, xZ, yZ;
+ int cnt_restarts;
+ int ret;
+
+ mbedtls_ecp_group_init( &grp ); mbedtls_ecp_point_init( &R );
+ mbedtls_mpi_init( &dA ); mbedtls_mpi_init( &xA ); mbedtls_mpi_init( &yA );
+ mbedtls_mpi_init( &dB ); mbedtls_mpi_init( &xZ ); mbedtls_mpi_init( &yZ );
+
+ TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
+
+ TEST_ASSERT( mbedtls_mpi_read_string( &dA, 16, dA_str ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_read_string( &xA, 16, xA_str ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_read_string( &yA, 16, yA_str ) == 0 );
+
+ TEST_ASSERT( mbedtls_mpi_read_string( &dB, 16, dB_str ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_read_string( &xZ, 16, xZ_str ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_read_string( &yZ, 16, yZ_str ) == 0 );
+
+ mbedtls_ecp_set_max_ops( (unsigned) max_ops );
+
+ /* Base point case */
+ cnt_restarts = 0;
+ do {
+ ret = mbedtls_ecp_mul( &grp, &R, &dA, &grp.G, NULL, NULL );
+ TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
+
+ if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
+ cnt_restarts++;
+ }
+ while( ret != 0 );
+
+ TEST_ASSERT( mbedtls_mpi_cmp_mpi( &R.X, &xA ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_cmp_mpi( &R.Y, &yA ) == 0 );
+
+ TEST_ASSERT( cnt_restarts >= min_restarts );
+ TEST_ASSERT( cnt_restarts <= max_restarts );
+
+ /* Do we leak memory when doing it twice in a row? */
+ do {
+ ret = mbedtls_ecp_mul( &grp, &R, &dA, &grp.G, NULL, NULL );
+ TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
+ }
+ while( ret != 0 );
+
+ /* Non-base point case */
+ cnt_restarts = 0;
+ do {
+ ret = mbedtls_ecp_mul( &grp, &R, &dB, &R, NULL, NULL );
+ TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
+
+ if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
+ cnt_restarts++;
+ }
+ while( ret != 0 );
+
+ TEST_ASSERT( mbedtls_mpi_cmp_mpi( &R.X, &xZ ) == 0 );
+ TEST_ASSERT( mbedtls_mpi_cmp_mpi( &R.Y, &yZ ) == 0 );
+
+ TEST_ASSERT( cnt_restarts >= min_restarts );
+ TEST_ASSERT( cnt_restarts <= max_restarts );
+
+ /* Do we leak memory when doing it twice in a row? */
+ do {
+ ret = mbedtls_ecp_mul( &grp, &R, &dB, &R, NULL, NULL );
+ TEST_ASSERT( ret == 0 || ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
+ }
+ while( ret != 0 );
+
+exit:
+ mbedtls_ecp_group_free( &grp ); mbedtls_ecp_point_free( &R );
+ mbedtls_mpi_free( &dA ); mbedtls_mpi_free( &xA ); mbedtls_mpi_free( &yA );
+ mbedtls_mpi_free( &dB ); mbedtls_mpi_free( &xZ ); mbedtls_mpi_free( &yZ );
+}
+/* END_CASE */
+
/* BEGIN_CASE */
void ecp_test_vect( int id, char *dA_str, char *xA_str, char *yA_str,
char *dB_str, char *xB_str, char *yB_str, char *xZ_str,