Commit 1a967289 authored by Manuel Pégourié-Gonnard's avatar Manuel Pégourié-Gonnard
Browse files

Add function parsing a TLS ECParameters record

parent cf4a70c8
......@@ -89,12 +89,14 @@ ecp_group;
* \warning This library does not support validation of arbitrary domain
* parameters. Therefore, only well-known domain parameters from trusted
* sources should be used. See ecp_use_known_dp().
*
* \note The values are taken from RFC 4492's enum NamedCurve.
*/
#define POLARSSL_ECP_DP_SECP192R1 0
#define POLARSSL_ECP_DP_SECP224R1 1
#define POLARSSL_ECP_DP_SECP256R1 2
#define POLARSSL_ECP_DP_SECP384R1 3
#define POLARSSL_ECP_DP_SECP521R1 4
#define POLARSSL_ECP_DP_SECP192R1 19
#define POLARSSL_ECP_DP_SECP224R1 21
#define POLARSSL_ECP_DP_SECP256R1 23
#define POLARSSL_ECP_DP_SECP384R1 24
#define POLARSSL_ECP_DP_SECP521R1 25
/**
* Maximum bit size of the groups (that is, of N)
......@@ -120,6 +122,12 @@ ecp_group;
#define POLARSSL_ECP_PF_UNCOMPRESSED 0 /**< Uncompressed point format */
#define POLARSSL_ECP_PF_COMPRESSED 1 /**< Compressed point format */
/*
* Some constants from RFC 4492 (ECC for TLS)
*/
#define POLARSSL_ECP_TLS_NAMED_CURVE 3 /**< ECCurveType named_curve */
#ifdef __cplusplus
extern "C" {
#endif
......@@ -259,6 +267,7 @@ int ecp_write_binary( const ecp_group *grp, const ecp_point *P, int format,
*/
int ecp_read_binary( const ecp_group *grp, ecp_point *P, int format,
const unsigned char *buf, size_t ilen );
/**
* \brief Set a group using well-known domain parameters
*
......@@ -269,9 +278,23 @@ int ecp_read_binary( const ecp_group *grp, ecp_point *P, int format,
* POLARSSL_ERR_MPI_XXX if initialization failed
* POLARSSL_ERR_ECP_GENERIC if index is out of range
*
* \note Index should be a POLARSSL_ECP_DP_XXX macro.
* \note Index should be a value of RFC 4492's enum NamdeCurve,
* possibly in the form of a POLARSSL_ECP_DP_XXX macro.
*/
int ecp_use_known_dp( ecp_group *grp, uint16_t index );
/**
* \brief Read a group from an ECParameters record
*
* \param grp Destination group
* \param buf Start of input buffer
* \param len Buffer length
*
* \return O if successful,
* POLARSSL_ERR_MPI_XXX if initialization failed
* POLARSSL_ERR_ECP_BAD_INPUT_DATA if input is invalid
*/
int ecp_use_known_dp( ecp_group *grp, size_t index );
int ecp_tls_read_group( ecp_group *grp, const unsigned char *buf, size_t len );
/**
* \brief Addition: R = P + Q
......
......@@ -29,6 +29,7 @@
* SEC1 http://www.secg.org/index.php?action=secg,docs_secg
* GECC = Guide to Elliptic Curve Cryptography - Hankerson, Menezes, Vanstone
* FIPS 186-3 http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf
* RFC 4492 for the related TLS structures and constants
*/
#include "polarssl/config.h"
......@@ -493,7 +494,7 @@ cleanup:
/*
* Set a group using well-known domain parameters
*/
int ecp_use_known_dp( ecp_group *grp, size_t index )
int ecp_use_known_dp( ecp_group *grp, uint16_t index )
{
switch( index )
{
......@@ -525,7 +526,33 @@ int ecp_use_known_dp( ecp_group *grp, size_t index )
SECP521R1_GX, SECP521R1_GY, SECP521R1_N ) );
}
return( POLARSSL_ERR_ECP_GENERIC );
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
}
/*
* Set a group from an ECParameters record (RFC 4492)
*/
int ecp_tls_read_group( ecp_group *grp, const unsigned char *buf, size_t len )
{
uint16_t namedcurve;
/*
* We expect at least three bytes (see below)
*/
if( len < 3 )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
/*
* First byte is curve_type; only named_curve is handled
*/
if( *buf++ != POLARSSL_ECP_TLS_NAMED_CURVE )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
/*
* Next two bytes are the namedcurve
*/
namedcurve = 256 * buf[0] + buf[1];
return ecp_use_known_dp( grp, namedcurve );
}
/*
......
......@@ -184,6 +184,21 @@ ecp_read_binary:SECP192R1:"0548d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ce
ECP read binary #6 (non-zero, OK)
ecp_read_binary:SECP192R1:"0448d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc99336ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":UNCOMPRESSED:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"6ceed4d7cba482e288669ee1b6415626d6f34d28501e060c":"01":0
ECP read params #1 (record too short)
ecp_read_params:"0313":POLARSSL_ERR_ECP_BAD_INPUT_DATA:0
ECP read params #2 (bad curve_type)
ecp_read_params:"010013":POLARSSL_ERR_ECP_BAD_INPUT_DATA:0
ECP read params #3 (unknown curve)
ecp_read_params:"030010":POLARSSL_ERR_ECP_BAD_INPUT_DATA:0
ECP read params #4 (OK, buffer just fits)
ecp_read_params:"030017":0:256
ECP read params #5 (OK, buffer continues)
ecp_read_params:"030018DEAD":0:384
ECP gen keypair
ecp_gen_keypair:SECP192R1
......
......@@ -322,6 +322,28 @@ ecp_gen_keypair:id
}
END_CASE
BEGIN_CASE
ecp_read_params:record:ret:bits
{
ecp_group grp;
unsigned char buf[10];
int len, ret;
ecp_group_init( &grp );
memset( buf, 0x00, sizeof( buf ) );
len = unhexify( buf, {record} );
ret = ecp_tls_read_group( &grp, buf, len );
TEST_ASSERT( ret == {ret} );
if( ret == 0)
TEST_ASSERT( mpi_msb( &grp.P ) == {bits} );
ecp_group_free( &grp );
}
END_CASE
BEGIN_CASE
ecp_selftest:
{
......
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