Make RNG parameters mandatory in ECP functions
Fix trivial faulty calls in ECP test suite and ECP/ECJPAKE self-tests (by
adding a dummy RNG).
Several tests suites are not passing yet, as a couple of library
function do call ecp_mul() with a NULL RNG. The complexity of the fixes
range from "simple refactoring" to "requires API changes", so these will
be addressed in separate commits.
This makes the option MBEDTLS_ECP_NO_INTERNAL_RNG, as well as the whole
"internal RNG" code, obsolete. This will be addressed in a future
commit, after getting the test suites to pass again.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/ecp.c b/library/ecp.c
index 044bbe1..873b4c8 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -2684,6 +2684,9 @@
ECP_VALIDATE_RET( m != NULL );
ECP_VALIDATE_RET( P != NULL );
+ if( f_rng == NULL )
+ return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+
#if defined(MBEDTLS_ECP_RESTARTABLE)
/* reset ops count for this call if top-level */
if( rs_ctx != NULL && rs_ctx->depth++ == 0 )
@@ -3315,6 +3318,28 @@
#if defined(MBEDTLS_SELF_TEST)
+/*
+ * PRNG for test - !!!INSECURE NEVER USE IN PRODUCTION!!!
+ *
+ * This is the linear congruential generator from numerical recipes,
+ * except we only use the low byte as the output. See
+ * https://en.wikipedia.org/wiki/Linear_congruential_generator#Parameters_in_common_use
+ */
+static int self_test_rng( void *ctx, unsigned char *out, size_t len )
+{
+ static uint32_t state = 42;
+
+ (void) ctx;
+
+ for( size_t i = 0; i < len; i++ )
+ {
+ state = state * 1664525u + 1013904223u;
+ out[i] = (unsigned char) state;
+ }
+
+ return( 0 );
+}
+
/* Adjust the exponent to be a valid private point for the specified curve.
* This is sometimes necessary because we use a single set of exponents
* for all curves but the validity of values depends on the curve. */
@@ -3370,7 +3395,7 @@
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( m, 16, exponents[0] ) );
MBEDTLS_MPI_CHK( self_test_adjust_exponent( grp, m ) );
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, self_test_rng, NULL ) );
for( i = 1; i < n_exponents; i++ )
{
@@ -3383,7 +3408,7 @@
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( m, 16, exponents[i] ) );
MBEDTLS_MPI_CHK( self_test_adjust_exponent( grp, m ) );
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, self_test_rng, NULL ) );
if( add_count != add_c_prev ||
dbl_count != dbl_c_prev ||
@@ -3461,7 +3486,7 @@
mbedtls_printf( " ECP SW test #1 (constant op_count, base point G): " );
/* Do a dummy multiplication first to trigger precomputation */
MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &m, 2 ) );
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &P, &m, &grp.G, NULL, NULL ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &P, &m, &grp.G, self_test_rng, NULL ) );
ret = self_test_point( verbose,
&grp, &R, &m, &grp.G,
sw_exponents,