Add olen parameter to ecp_ansi_write_group and ecp_ansi_write_point
Improve mbedtls_ecp_ansi_write_point
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 43d001c..badfe86 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -515,13 +515,14 @@
* \param grp ECP group used
* \param buf Buffer to write to
* \param size Buffer size
- *
- * \return Number of bytes written to \c buf,
+ * \param olen Number of bytes written to \c buf
+ * \return 0 on success
* or \c MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
* or \c MBEDTLS_ERR_OID_NOT_FOUND
*/
int mbedtls_ecp_ansi_write_group( const mbedtls_ecp_group *grp,
- unsigned char *p, size_t size );
+ unsigned char *p, size_t size,
+ size_t *olen );
/**
* \brief Export a point in ANSI X9.62/RFC5480 ECPoint
@@ -533,8 +534,9 @@
* \param format Point format, should be a MBEDTLS_ECP_PF_XXX macro
* \param p Buffer to write to
* \param size Buffer size
+ * \param olen Number of bytes written to \c buf
*
- * \return Number of bytes written to \c buf,
+ * \return 0 on success
* or \c MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
* or \c MBEDTLS_ERR_ECP_BAD_INPUT_DATA
* or \c MBEDTLS_ERR_ASN1_BUF_TOO_SMALL
@@ -542,7 +544,7 @@
int mbedtls_ecp_ansi_write_point( const mbedtls_ecp_keypair *ec,
int format,
unsigned char *p,
- size_t size );
+ size_t size, size_t *olen );
#endif /* defined(MBEDTLS_ASN1_WRITE_C) && defined(MBEDTLS_OID_C) */
/**
diff --git a/library/ecp.c b/library/ecp.c
index 851d230..58bffe4 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -2066,12 +2066,13 @@
#include "mbedtls/oid.h"
int mbedtls_ecp_ansi_write_group( const mbedtls_ecp_group *grp,
unsigned char *p,
- size_t size )
+ size_t size, size_t *olen )
{
const char *oid;
unsigned char *q;
size_t oid_length;
int ret;
+
ret = mbedtls_oid_get_oid_by_ec_grp( grp->id, &oid, &oid_length );
if( ret != 0 )
return( ret );
@@ -2079,36 +2080,38 @@
if( size < 2 + oid_length )
return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
q = p + 2 + oid_length;
- return( mbedtls_asn1_write_oid( &q, p, oid, oid_length ) );
+ *olen = mbedtls_asn1_write_oid( &q, p, oid, oid_length );
+ return ( 0 );
}
int mbedtls_ecp_ansi_write_point( const mbedtls_ecp_keypair *ec,
int format,
unsigned char *p,
- size_t size )
+ size_t size, size_t *olen )
{
unsigned char *q;
- size_t length;
- size_t tl_size = 3; /* room for the OCTET_STRING tag and length */
+ size_t tl_max_size = 3; /* room for the OCTET_STRING tag and length */
int ret;
- if( size < tl_size )
+
+ if( size < tl_max_size )
return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
- q = p + tl_size;
+
+ q = p + tl_max_size;
ret = mbedtls_ecp_point_write_binary( &ec->grp, &ec->Q,
format,
- &length, q, size - 3 );
+ olen, q, size - tl_max_size );
if( ret < 0 )
return( ret );
- ret = mbedtls_asn1_write_len( &q, p, length );
+ ret = mbedtls_asn1_write_len( &q, p, *olen );
if( ret < 0 )
return( ret );
ret = mbedtls_asn1_write_tag( &q, p, MBEDTLS_ASN1_OCTET_STRING );
if( ret < 0 )
return( ret );
- length += tl_size - ( q - p );
+ *olen += tl_max_size - ( q - p );
if( q != p )
- memmove( p, q, length );
- return( length );
+ memmove( p, q, *olen );
+ return( 0 );
}
#endif /* defined(MBEDTLS_ASN1_WRITE_C) && defined(MBEDTLS_OID_C) */
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 4b81090..a3cde43 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -420,17 +420,20 @@
unsigned char good[MBEDTLS_OID_EC_GRP_MAX_SIZE];
unsigned char tested[MBEDTLS_OID_EC_GRP_MAX_SIZE];
size_t good_len = unhexify( good, hex );
+ size_t received_len = 0;
int ret = 0;
mbedtls_ecp_group_init( &grp );
TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
/* Positive test */
- ret = mbedtls_ecp_ansi_write_group( &grp, tested, sizeof( tested ) );
- TEST_ASSERT( ret >= 0 && good_len == (unsigned) ret );
+ ret = mbedtls_ecp_ansi_write_group( &grp, tested, sizeof( tested ),
+ &received_len );
+ TEST_ASSERT( ret == 0 && good_len == (unsigned) received_len );
TEST_ASSERT( memcmp( good, tested, good_len ) == 0 );
/* Buffer too small */
- TEST_ASSERT( mbedtls_ecp_ansi_write_group( &grp, tested, good_len - 1 ) ==
+ TEST_ASSERT( mbedtls_ecp_ansi_write_group( &grp, tested, good_len - 1,
+ &received_len ) ==
MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
exit:
@@ -444,20 +447,23 @@
unsigned char good_buf[1000];
unsigned char tested_buf[1000];
size_t good_len = unhexify( good_buf, good_hex );
+ size_t received_len = 0;
mbedtls_pk_context pk;
- int ret = 0;
+ int ret = -1;
mbedtls_pk_init( &pk );
TEST_ASSERT( mbedtls_pk_parse_public_keyfile( &pk, key_file ) == 0 );
/* Positive test */
ret = mbedtls_ecp_ansi_write_point( mbedtls_pk_ec( pk ), format,
- tested_buf, sizeof( tested_buf ) );
- TEST_ASSERT( ret >= 0 && good_len == (unsigned) ret );
+ tested_buf, sizeof( tested_buf ),
+ &received_len );
+ TEST_ASSERT( ret == 0 && good_len == (unsigned) received_len );
TEST_ASSERT( memcmp( good_buf, tested_buf, good_len ) == 0 );
/* Buffer too small */
TEST_ASSERT( mbedtls_ecp_ansi_write_point( mbedtls_pk_ec( pk ), format,
- tested_buf, good_len - 1 ) ==
+ tested_buf, good_len - 1,
+ &received_len ) ==
MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
exit: