Add functions for read/write ECPoint records
diff --git a/library/ecp.c b/library/ecp.c
index 0a27df2..b6c50f6 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -186,14 +186,14 @@
* Export a point into unsigned binary data (SEC1 2.3.3)
*/
int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
- size_t *olen, unsigned char *buf, size_t buflen )
+ uint8_t *olen, unsigned char *buf, size_t buflen )
{
int ret;
size_t plen;
if( format != POLARSSL_ECP_PF_UNCOMPRESSED &&
format != POLARSSL_ECP_PF_COMPRESSED )
- return( POLARSSL_ERR_ECP_GENERIC );
+ return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
/*
* Common case: P == 0
@@ -201,7 +201,7 @@
if( mpi_cmp_int( &P->Z, 0 ) == 0 )
{
if( buflen < 1 )
- return( POLARSSL_ERR_ECP_GENERIC );
+ return( POLARSSL_ERR_ECP_BUFFER_TOO_SMALL );
buf[0] = 0x00;
*olen = 1;
@@ -216,7 +216,7 @@
*olen = 2 * plen + 1;
if( buflen < *olen )
- return( POLARSSL_ERR_ECP_GENERIC );
+ return( POLARSSL_ERR_ECP_BUFFER_TOO_SMALL );
buf[0] = 0x04;
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
@@ -227,7 +227,7 @@
*olen = plen + 1;
if( buflen < *olen )
- return( POLARSSL_ERR_ECP_GENERIC );
+ return( POLARSSL_ERR_ECP_BUFFER_TOO_SMALL );
buf[0] = 0x02 + mpi_get_bit( &P->Y, 0 );
MPI_CHK( mpi_write_binary( &P->X, buf + 1, plen ) );
@@ -265,6 +265,49 @@
}
/*
+ * Import a point from a TLS ECPoint record (RFC 4492)
+ * struct {
+ * opaque point <1..2^8-1>;
+ * } ECPoint;
+ */
+int ecp_tls_read_point( const ecp_group *grp, ecp_point *pt,
+ const unsigned char *buf, size_t buf_len )
+{
+ unsigned char data_len;
+
+ /*
+ * We must have at least two bytes (1 for length, at least of for data)
+ */
+ if( buf_len < 2 )
+ return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
+
+ data_len = *buf++;
+ if( data_len < 1 || data_len > buf_len - 1 )
+ return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
+
+ return ecp_read_binary( grp, pt, POLARSSL_ECP_PF_UNCOMPRESSED,
+ buf, data_len );
+}
+
+/*
+ * Export a point as a TLS ECPoint record (RFC 4492)
+ * struct {
+ * opaque point <1..2^8-1>;
+ * } ECPoint;
+ */
+int ecp_tls_write_point( const ecp_group *grp, const ecp_point *pt,
+ int format, unsigned char *buf, size_t buf_len )
+{
+ /*
+ * buf_len must be at least one, for our length byte
+ */
+ if( buf_len < 1 )
+ return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
+
+ return ecp_write_binary( grp, pt, format, buf, buf + 1, buf_len - 1);
+}
+
+/*
* Wrapper around fast quasi-modp functions, with fall-back to mpi_mod_mpi.
* See the documentation of struct ecp_group.
*/