Commit ddc1caac authored by David Benjamin's avatar David Benjamin
Browse files

Document EC_POINT_get_affine_coordinates_*. 



In particular, x and y may be NULL, as used in ecdsa_ossl.c. Make use of
this in ecdh_ossl.c as well, to save an otherwise unnecessary temporary.

Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5532)
parent 0870c8ea

crypto/ec/ecdh_ossl.c

+4 −5
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ int ecdh_simple_compute_key(unsigned char **pout, size_t *poutlen, 
{

    BN_CTX *ctx;

    EC_POINT *tmp = NULL;

    BIGNUM *x = NULL, *y = NULL;

    BIGNUM *x = NULL;

    const BIGNUM *priv_key;

    const EC_GROUP *group;

    int ret = 0;
@@ -51,8 +51,7 @@ int ecdh_simple_compute_key(unsigned char **pout, size_t *poutlen, 
        goto err;

    BN_CTX_start(ctx);

    x = BN_CTX_get(ctx);

    y = BN_CTX_get(ctx);

    if (y == NULL) {

    if (x == NULL) {

        ECerr(EC_F_ECDH_SIMPLE_COMPUTE_KEY, ERR_R_MALLOC_FAILURE);

        goto err;

    }
@@ -86,14 +85,14 @@ int ecdh_simple_compute_key(unsigned char **pout, size_t *poutlen, 


    if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==

        NID_X9_62_prime_field) {

        if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, y, ctx)) {

        if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, NULL, ctx)) {

            ECerr(EC_F_ECDH_SIMPLE_COMPUTE_KEY, EC_R_POINT_ARITHMETIC_FAILURE);

            goto err;

        }

    }

#ifndef OPENSSL_NO_EC2M

    else {

        if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, y, ctx)) {

        if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, NULL, ctx)) {

            ECerr(EC_F_ECDH_SIMPLE_COMPUTE_KEY, EC_R_POINT_ARITHMETIC_FAILURE);

            goto err;

        }

doc/man3/EC_POINT_new.pod

+4 −1
Original line number Diff line number Diff line
@@ -99,7 +99,10 @@ be at infinity by calling EC_POINT_set_to_infinity(). 
The affine co-ordinates for a point describe a point in terms of its x and y

position. The functions EC_POINT_set_affine_coordinates_GFp() and

EC_POINT_set_affine_coordinates_GF2m() set the B<x> and B<y> co-ordinates for

the point B<p> defined over the curve given in B<group>.

the point B<p> defined over the curve given in B<group>. The functions

EC_POINT_get_affine_coordinates_GFp() and

EC_POINT_get_affine_coordinates_GF2m() set B<x> and B<y>, either of which may

be NULL, to the corresponding coordinates of B<p>.



As well as the affine co-ordinates, a point can alternatively be described in

terms of its Jacobian projective co-ordinates (for Fp curves only). Jacobian