


#include "internal/deprecated.h"

#include <openssl/err.h>

#include "ec_local.h"

#ifndef OPENSSL_NO_EC2M


int ossl_ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group,
                                                   EC_POINT *point,
                                                   const BIGNUM *x_, int y_bit,
                                                   BN_CTX *ctx)
{
    BIGNUM *tmp, *x, *y, *z;
    int ret = 0, z0;
#ifndef FIPS_MODULE
    BN_CTX *new_ctx = NULL;

    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new();
        if (ctx == NULL)
            return 0;
    }
#endif

    y_bit = (y_bit != 0) ? 1 : 0;

    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    z = BN_CTX_get(ctx);
    if (z == NULL)
        goto err;

    if (!BN_GF2m_mod_arr(x, x_, group->poly))
        goto err;
    if (BN_is_zero(x)) {
        if (!BN_GF2m_mod_sqrt_arr(y, group->b, group->poly, ctx))
            goto err;
    } else {
        if (!group->meth->field_sqr(group, tmp, x, ctx))
            goto err;
        if (!group->meth->field_div(group, tmp, group->b, tmp, ctx))
            goto err;
        if (!BN_GF2m_add(tmp, group->a, tmp))
            goto err;
        if (!BN_GF2m_add(tmp, x, tmp))
            goto err;
        ERR_set_mark();
        if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx)) {
#ifndef FIPS_MODULE
            unsigned long err = ERR_peek_last_error();

            if (ERR_GET_LIB(err) == ERR_LIB_BN
                && ERR_GET_REASON(err) == BN_R_NO_SOLUTION) {
                ERR_pop_to_mark();
                ERR_raise(ERR_LIB_EC, EC_R_INVALID_COMPRESSED_POINT);
            } else
#endif
            {
                ERR_clear_last_mark();
                ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
            }
            goto err;
        }
        ERR_clear_last_mark();
        z0 = (BN_is_odd(z)) ? 1 : 0;
        if (!group->meth->field_mul(group, y, x, z, ctx))
            goto err;
        if (z0 != y_bit) {
            if (!BN_GF2m_add(y, y, x))
                goto err;
        }
    }

    if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
        goto err;

    ret = 1;

 err:
    BN_CTX_end(ctx);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    return ret;
}


size_t ossl_ec_GF2m_simple_point2oct(const EC_GROUP *group,
                                     const EC_POINT *point,
                                     point_conversion_form_t form,
                                     unsigned char *buf, size_t len, BN_CTX *ctx)
{
    size_t ret;
    int used_ctx = 0;
    BIGNUM *x, *y, *yxi;
    size_t field_len, i, skip;
#ifndef FIPS_MODULE
    BN_CTX *new_ctx = NULL;
#endif

    if ((form != POINT_CONVERSION_COMPRESSED)
        && (form != POINT_CONVERSION_UNCOMPRESSED)
        && (form != POINT_CONVERSION_HYBRID)) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_FORM);
        goto err;
    }

    if (EC_POINT_is_at_infinity(group, point)) {
        
        if (buf != NULL) {
            if (len < 1) {
                ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
                return 0;
            }
            buf[0] = 0;
        }
        return 1;
    }

    
    field_len = (EC_GROUP_get_degree(group) + 7) / 8;
    ret =
        (form ==
         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;

    
    if (buf != NULL) {
        if (len < ret) {
            ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
            goto err;
        }

#ifndef FIPS_MODULE
        if (ctx == NULL) {
            ctx = new_ctx = BN_CTX_new();
            if (ctx == NULL)
                return 0;
        }
#endif

        BN_CTX_start(ctx);
        used_ctx = 1;
        x = BN_CTX_get(ctx);
        y = BN_CTX_get(ctx);
        yxi = BN_CTX_get(ctx);
        if (yxi == NULL)
            goto err;

        if (!EC_POINT_get_affine_coordinates(group, point, x, y, ctx))
            goto err;

        buf[0] = form;
        if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x)) {
            if (!group->meth->field_div(group, yxi, y, x, ctx))
                goto err;
            if (BN_is_odd(yxi))
                buf[0]++;
        }

        i = 1;

        skip = field_len - BN_num_bytes(x);
        if (skip > field_len) {
            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
            goto err;
        }
        while (skip > 0) {
            buf[i++] = 0;
            skip--;
        }
        skip = BN_bn2bin(x, buf + i);
        i += skip;
        if (i != 1 + field_len) {
            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
            goto err;
        }

        if (form == POINT_CONVERSION_UNCOMPRESSED
            || form == POINT_CONVERSION_HYBRID) {
            skip = field_len - BN_num_bytes(y);
            if (skip > field_len) {
                ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                goto err;
            }
            while (skip > 0) {
                buf[i++] = 0;
                skip--;
            }
            skip = BN_bn2bin(y, buf + i);
            i += skip;
        }

        if (i != ret) {
            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
            goto err;
        }
    }

    if (used_ctx)
        BN_CTX_end(ctx);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    return ret;

 err:
    if (used_ctx)
        BN_CTX_end(ctx);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    return 0;
}


int ossl_ec_GF2m_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
                                  const unsigned char *buf, size_t len,
                                  BN_CTX *ctx)
{
    point_conversion_form_t form;
    int y_bit, m;
    BIGNUM *x, *y, *yxi;
    size_t field_len, enc_len;
    int ret = 0;
#ifndef FIPS_MODULE
    BN_CTX *new_ctx = NULL;
#endif

    if (len == 0) {
        ERR_raise(ERR_LIB_EC, EC_R_BUFFER_TOO_SMALL);
        return 0;
    }

    
    y_bit = buf[0] & 1;
    form = buf[0] & ~1U;

    if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
        && (form != POINT_CONVERSION_UNCOMPRESSED)
        && (form != POINT_CONVERSION_HYBRID)) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        return 0;
    }
    if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        return 0;
    }

    
    if (form == 0) {
        if (len != 1) {
            ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
            return 0;
        }

        return EC_POINT_set_to_infinity(group, point);
    }

    m = EC_GROUP_get_degree(group);
    field_len = (m + 7) / 8;
    enc_len =
        (form ==
         POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;

    if (len != enc_len) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        return 0;
    }

#ifndef FIPS_MODULE
    if (ctx == NULL) {
        ctx = new_ctx = BN_CTX_new();
        if (ctx == NULL)
            return 0;
    }
#endif

    BN_CTX_start(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    yxi = BN_CTX_get(ctx);
    if (yxi == NULL)
        goto err;

    if (!BN_bin2bn(buf + 1, field_len, x))
        goto err;
    if (BN_num_bits(x) > m) {
        ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
        goto err;
    }

    if (form == POINT_CONVERSION_COMPRESSED) {
        if (!EC_POINT_set_compressed_coordinates(group, point, x, y_bit, ctx))
            goto err;
    } else {
        if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
            goto err;
        if (BN_num_bits(y) > m) {
            ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
            goto err;
        }
        if (form == POINT_CONVERSION_HYBRID) {
            
            if (BN_is_zero(x)) {
                if (y_bit != 0) {
                    ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
                    goto err;
                }
            } else {
                if (!group->meth->field_div(group, yxi, y, x, ctx))
                    goto err;
                if (y_bit != BN_is_odd(yxi)) {
                    ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
                    goto err;
                }
            }
        }

        
        if (!EC_POINT_set_affine_coordinates(group, point, x, y, ctx))
            goto err;
    }

    ret = 1;

 err:
    BN_CTX_end(ctx);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    return ret;
}
#endif
