ASN.1: test that we can parse what we can write
In asn1_write tests, when there's a parsing function corresponding to the
write function, call it and check that it can parse what we wrote.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_asn1write.function b/tests/suites/test_suite_asn1write.function
index 2b5697a..daa3830 100644
--- a/tests/suites/test_suite_asn1write.function
+++ b/tests/suites/test_suite_asn1write.function
@@ -16,6 +16,8 @@
int generic_write_start_step( generic_write_data_t *data )
{
mbedtls_test_set_step( data->size );
+ mbedtls_free( data->output );
+ data->output = NULL;
ASSERT_ALLOC( data->output, data->size == 0 ? 1 : data->size );
data->end = data->output + data->size;
data->p = data->end;
@@ -45,8 +47,6 @@
ok = 1;
exit:
- mbedtls_free( data->output );
- data->output = NULL;
return( ok );
}
@@ -70,6 +70,7 @@
ret = mbedtls_asn1_write_null( &data.p, data.start );
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+ /* There's no parsing function for NULL. */
}
exit:
@@ -90,6 +91,14 @@
ret = mbedtls_asn1_write_bool( &data.p, data.start, val );
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ if( ret >= 0 )
+ {
+ int read = 0xdeadbeef;
+ TEST_EQUAL( mbedtls_asn1_get_bool( &data.p, data.end, &read ), 0 );
+ TEST_EQUAL( val, read );
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
exit:
@@ -110,6 +119,14 @@
ret = mbedtls_asn1_write_int( &data.p, data.start, val );
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ if( ret >= 0 )
+ {
+ int read = 0xdeadbeef;
+ TEST_EQUAL( mbedtls_asn1_get_int( &data.p, data.end, &read ), 0 );
+ TEST_EQUAL( val, read );
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
exit:
@@ -131,6 +148,14 @@
ret = mbedtls_asn1_write_enum( &data.p, data.start, val );
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ if( ret >= 0 )
+ {
+ int read = 0xdeadbeef;
+ TEST_EQUAL( mbedtls_asn1_get_enum( &data.p, data.end, &read ), 0 );
+ TEST_EQUAL( val, read );
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
exit:
@@ -142,10 +167,11 @@
void mbedtls_asn1_write_mpi( data_t *val, data_t *expected )
{
generic_write_data_t data = { NULL, NULL, NULL, NULL, 0 };
- mbedtls_mpi mpi;
+ mbedtls_mpi mpi, read;
int ret;
mbedtls_mpi_init( &mpi );
+ mbedtls_mpi_init( &read );
TEST_ASSERT( mbedtls_mpi_read_binary( &mpi, val->x, val->len ) == 0 );
for( data.size = 0; data.size <= expected->len + 1; data.size++ )
@@ -155,12 +181,21 @@
ret = mbedtls_asn1_write_mpi( &data.p, data.start, &mpi );
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ if( ret >= 0 )
+ {
+ TEST_EQUAL( mbedtls_asn1_get_mpi( &data.p, data.end, &read ), 0 );
+ TEST_EQUAL( 0, mbedtls_mpi_cmp_mpi( &mpi, &read ) );
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
+ /* Skip some intermediate lengths, they're boring. */
if( expected->len > 10 && data.size == 8 )
data.size = expected->len - 2;
}
exit:
mbedtls_mpi_free( &mpi );
+ mbedtls_mpi_free( &read );
mbedtls_free( data.output );
}
/* END_CASE */
@@ -208,6 +243,8 @@
}
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+ /* There's no parsing function for octet or character strings. */
+ /* Skip some intermediate lengths, they're boring. */
if( expected->len > 10 && data.size == 8 )
data.size = expected->len - 2;
}
@@ -224,6 +261,9 @@
{
generic_write_data_t data = { NULL, NULL, NULL, NULL, 0 };
int ret;
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ unsigned char *buf_complete = NULL;
+#endif /* MBEDTLS_ASN1_PARSE_C */
for( data.size = 0; data.size <= expected->len + 1; data.size++ )
{
@@ -240,10 +280,69 @@
ret -= par_len;
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ /* Only do a parse-back test if the parameters aren't too large for
+ * a small-heap environment. The boundary is somewhat arbitrary. */
+ if( ret >= 0 && par_len <= 1234 )
+ {
+ mbedtls_asn1_buf alg = {0, 0, NULL};
+ mbedtls_asn1_buf params = {0, 0, NULL};
+ /* The writing function doesn't write the parameters unless
+ * they're null: it only takes their length as input. But the
+ * parsing function requires the parameters to be present.
+ * Thus make up parameters. */
+ size_t data_len = data.end - data.p;
+ size_t len_complete = data_len + par_len;
+ unsigned char expected_params_tag;
+ size_t expected_params_len;
+ ASSERT_ALLOC( buf_complete, len_complete );
+ unsigned char *end_complete = buf_complete + len_complete;
+ memcpy( buf_complete, data.p, data_len );
+ if( par_len == 0 )
+ {
+ /* mbedtls_asn1_write_algorithm_identifier() wrote a NULL */
+ expected_params_tag = 0x05;
+ expected_params_len = 0;
+ }
+ else if( par_len >= 2 && par_len < 2 + 128 )
+ {
+ /* Write an OCTET STRING with a short length encoding */
+ expected_params_tag = buf_complete[data_len] = 0x04;
+ expected_params_len = par_len - 2;
+ buf_complete[data_len + 1] = (unsigned char) expected_params_len;
+ }
+ else if( par_len >= 4 + 128 && par_len < 3 + 256 * 256 )
+ {
+ /* Write an OCTET STRING with a two-byte length encoding */
+ expected_params_tag = buf_complete[data_len] = 0x04;
+ expected_params_len = par_len - 4;
+ buf_complete[data_len + 1] = 0x82;
+ buf_complete[data_len + 2] = (unsigned char) ( expected_params_len >> 8 );
+ buf_complete[data_len + 3] = (unsigned char) ( expected_params_len );
+ }
+ else
+ {
+ TEST_ASSERT( ! "Bad test data: invalid length of ASN.1 element" );
+ }
+ unsigned char *p = buf_complete;
+ TEST_EQUAL( mbedtls_asn1_get_alg( &p, end_complete,
+ &alg, ¶ms ), 0 );
+ TEST_EQUAL( alg.tag, MBEDTLS_ASN1_OID );
+ ASSERT_COMPARE( alg.p, alg.len, oid->x, oid->len );
+ TEST_EQUAL( params.tag, expected_params_tag );
+ TEST_EQUAL( params.len, expected_params_len );
+ mbedtls_free( buf_complete );
+ buf_complete = NULL;
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
exit:
mbedtls_free( data.output );
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ mbedtls_free( buf_complete );
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
/* END_CASE */
@@ -308,6 +407,34 @@
const unsigned char *buf, size_t bits ) =
( is_named ? mbedtls_asn1_write_named_bitstring :
mbedtls_asn1_write_bitstring );
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ unsigned char *masked_bitstring = NULL;
+#endif /* MBEDTLS_ASN1_PARSE_C */
+
+ /* The API expects `bitstring->x` to contain `bits` bits. */
+ size_t byte_length = ( bits + 7 ) / 8;
+ TEST_ASSERT( bitstring->len >= byte_length );
+
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ ASSERT_ALLOC( masked_bitstring, byte_length );
+ memcpy( masked_bitstring, bitstring->x, byte_length );
+ if( bits % 8 != 0 )
+ masked_bitstring[byte_length - 1] &= ~( 0xff >> ( bits % 8 ) );
+ size_t value_bits = bits;
+ if( is_named )
+ {
+ /* In a named bit string, all trailing 0 bits are removed. */
+ while( byte_length > 0 && masked_bitstring[byte_length - 1] == 0 )
+ --byte_length;
+ value_bits = 8 * byte_length;
+ if( byte_length > 0 )
+ {
+ unsigned char last_byte = masked_bitstring[byte_length - 1];
+ for( unsigned b = 1; b < 0xff && ( last_byte & b ) == 0; b <<= 1 )
+ --value_bits;
+ }
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
for( data.size = 0; data.size <= expected->len + 1; data.size++ )
{
@@ -316,10 +443,24 @@
ret = ( *func )( &data.p, data.start, bitstring->x, bits );
if( ! generic_write_finish_step( &data, expected, ret ) )
goto exit;
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ if( ret >= 0 )
+ {
+ mbedtls_asn1_bitstring read = {0, 0, NULL};
+ TEST_EQUAL( mbedtls_asn1_get_bitstring( &data.p, data.end,
+ &read ), 0 );
+ ASSERT_COMPARE( read.p, read.len,
+ masked_bitstring, byte_length );
+ TEST_EQUAL( read.unused_bits, 8 * byte_length - value_bits );
+ }
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
exit:
mbedtls_free( data.output );
+#if defined(MBEDTLS_ASN1_PARSE_C)
+ mbedtls_free( masked_bitstring );
+#endif /* MBEDTLS_ASN1_PARSE_C */
}
/* END_CASE */