


#include "internal/deprecated.h"

#include <string.h>
#include <openssl/err.h>

#include "internal/cryptlib.h"
#include "crypto/bn.h"
#include "ec_local.h"
#include "internal/refcount.h"




struct ec_pre_comp_st {
    const EC_GROUP *group;      
    size_t blocksize;           
    size_t numblocks;           
    size_t w;                   
    EC_POINT **points;          
    size_t num;                 
    CRYPTO_REF_COUNT references;
};

static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group)
{
    EC_PRE_COMP *ret = NULL;

    if (!group)
        return NULL;

    ret = OPENSSL_zalloc(sizeof(*ret));
    if (ret == NULL)
        return ret;

    ret->group = group;
    ret->blocksize = 8;         
    ret->w = 4;                 

    if (!CRYPTO_NEW_REF(&ret->references, 1)) {
        OPENSSL_free(ret);
        return NULL;
    }
    return ret;
}

EC_PRE_COMP *EC_ec_pre_comp_dup(EC_PRE_COMP *pre)
{
    int i;
    if (pre != NULL)
        CRYPTO_UP_REF(&pre->references, &i);
    return pre;
}

void EC_ec_pre_comp_free(EC_PRE_COMP *pre)
{
    int i;

    if (pre == NULL)
        return;

    CRYPTO_DOWN_REF(&pre->references, &i);
    REF_PRINT_COUNT("EC_ec", pre);
    if (i > 0)
        return;
    REF_ASSERT_ISNT(i < 0);

    if (pre->points != NULL) {
        EC_POINT **pts;

        for (pts = pre->points; *pts != NULL; pts++)
            EC_POINT_free(*pts);
        OPENSSL_free(pre->points);
    }
    CRYPTO_FREE_REF(&pre->references);
    OPENSSL_free(pre);
}

#define EC_POINT_BN_set_flags(P, flags) do { \
    BN_set_flags((P)->X, (flags)); \
    BN_set_flags((P)->Y, (flags)); \
    BN_set_flags((P)->Z, (flags)); \
} while(0)


int ossl_ec_scalar_mul_ladder(const EC_GROUP *group, EC_POINT *r,
                              const BIGNUM *scalar, const EC_POINT *point,
                              BN_CTX *ctx)
{
    int i, cardinality_bits, group_top, kbit, pbit, Z_is_one;
    EC_POINT *p = NULL;
    EC_POINT *s = NULL;
    BIGNUM *k = NULL;
    BIGNUM *lambda = NULL;
    BIGNUM *cardinality = NULL;
    int ret = 0;

    
    if (point != NULL && EC_POINT_is_at_infinity(group, point))
        return EC_POINT_set_to_infinity(group, r);

    if (BN_is_zero(group->order)) {
        ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_ORDER);
        return 0;
    }
    if (BN_is_zero(group->cofactor)) {
        ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_COFACTOR);
        return 0;
    }

    BN_CTX_start(ctx);

    if (((p = EC_POINT_new(group)) == NULL)
        || ((s = EC_POINT_new(group)) == NULL)) {
        ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
        goto err;
    }

    if (point == NULL) {
        if (!EC_POINT_copy(p, group->generator)) {
            ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
            goto err;
        }
    } else {
        if (!EC_POINT_copy(p, point)) {
            ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
            goto err;
        }
    }

    EC_POINT_BN_set_flags(p, BN_FLG_CONSTTIME);
    EC_POINT_BN_set_flags(r, BN_FLG_CONSTTIME);
    EC_POINT_BN_set_flags(s, BN_FLG_CONSTTIME);

    cardinality = BN_CTX_get(ctx);
    lambda = BN_CTX_get(ctx);
    k = BN_CTX_get(ctx);
    if (k == NULL) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }

    if (!BN_mul(cardinality, group->order, group->cofactor, ctx)) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }

    
    cardinality_bits = BN_num_bits(cardinality);
    group_top = bn_get_top(cardinality);
    if ((bn_wexpand(k, group_top + 2) == NULL)
        || (bn_wexpand(lambda, group_top + 2) == NULL)) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }

    if (!BN_copy(k, scalar)) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }

    BN_set_flags(k, BN_FLG_CONSTTIME);

    if ((BN_num_bits(k) > cardinality_bits) || (BN_is_negative(k))) {
        
        if (!BN_nnmod(k, k, cardinality, ctx)) {
            ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
            goto err;
        }
    }

    if (!BN_add(lambda, k, cardinality)) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }
    BN_set_flags(lambda, BN_FLG_CONSTTIME);
    if (!BN_add(k, lambda, cardinality)) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }
    
    kbit = BN_is_bit_set(lambda, cardinality_bits);
    BN_consttime_swap(kbit, k, lambda, group_top + 2);

    group_top = bn_get_top(group->field);
    if ((bn_wexpand(s->X, group_top) == NULL)
        || (bn_wexpand(s->Y, group_top) == NULL)
        || (bn_wexpand(s->Z, group_top) == NULL)
        || (bn_wexpand(r->X, group_top) == NULL)
        || (bn_wexpand(r->Y, group_top) == NULL)
        || (bn_wexpand(r->Z, group_top) == NULL)
        || (bn_wexpand(p->X, group_top) == NULL)
        || (bn_wexpand(p->Y, group_top) == NULL)
        || (bn_wexpand(p->Z, group_top) == NULL)) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }

    
    if (!p->Z_is_one && (group->meth->make_affine == NULL
                         || !group->meth->make_affine(group, p, ctx))) {
            ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
            goto err;
    }

    
    if (!ec_point_ladder_pre(group, r, s, p, ctx)) {
        ERR_raise(ERR_LIB_EC, EC_R_LADDER_PRE_FAILURE);
        goto err;
    }

    
    pbit = 1;

#define EC_POINT_CSWAP(c, a, b, w, t) do {         \
        BN_consttime_swap(c, (a)->X, (b)->X, w);   \
        BN_consttime_swap(c, (a)->Y, (b)->Y, w);   \
        BN_consttime_swap(c, (a)->Z, (b)->Z, w);   \
        t = ((a)->Z_is_one ^ (b)->Z_is_one) & (c); \
        (a)->Z_is_one ^= (t);                      \
        (b)->Z_is_one ^= (t);                      \
} while(0)

    

    for (i = cardinality_bits - 1; i >= 0; i--) {
        kbit = BN_is_bit_set(k, i) ^ pbit;
        EC_POINT_CSWAP(kbit, r, s, group_top, Z_is_one);

        
        if (!ec_point_ladder_step(group, r, s, p, ctx)) {
            ERR_raise(ERR_LIB_EC, EC_R_LADDER_STEP_FAILURE);
            goto err;
        }
        
        pbit ^= kbit;
    }
    
    EC_POINT_CSWAP(pbit, r, s, group_top, Z_is_one);
#undef EC_POINT_CSWAP

    
    if (!ec_point_ladder_post(group, r, s, p, ctx)) {
        ERR_raise(ERR_LIB_EC, EC_R_LADDER_POST_FAILURE);
        goto err;
    }

    ret = 1;

 err:
    EC_POINT_free(p);
    EC_POINT_clear_free(s);
    BN_CTX_end(ctx);

    return ret;
}

#undef EC_POINT_BN_set_flags


#define EC_window_bits_for_scalar_size(b) \
                ((size_t) \
                 ((b) >= 2000 ? 6 : \
                  (b) >=  800 ? 5 : \
                  (b) >=  300 ? 4 : \
                  (b) >=   70 ? 3 : \
                  (b) >=   20 ? 2 : \
                  1))


int ossl_ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
                     size_t num, const EC_POINT *points[],
                     const BIGNUM *scalars[], BN_CTX *ctx)
{
    const EC_POINT *generator = NULL;
    EC_POINT *tmp = NULL;
    size_t totalnum;
    size_t blocksize = 0, numblocks = 0; 
    size_t pre_points_per_block = 0;
    size_t i, j;
    int k;
    int r_is_inverted = 0;
    int r_is_at_infinity = 1;
    size_t *wsize = NULL;       
    signed char **wNAF = NULL;  
    size_t *wNAF_len = NULL;
    size_t max_len = 0;
    size_t num_val;
    EC_POINT **val = NULL;      
    EC_POINT **v;
    EC_POINT ***val_sub = NULL; 
    const EC_PRE_COMP *pre_comp = NULL;
    int num_scalar = 0;         
    int ret = 0;

    if (!BN_is_zero(group->order) && !BN_is_zero(group->cofactor)) {
        
        if ((scalar != group->order) && (scalar != NULL) && (num == 0)) {
            
            return ossl_ec_scalar_mul_ladder(group, r, scalar, NULL, ctx);
        }
        if ((scalar == NULL) && (num == 1) && (scalars[0] != group->order)) {
            
            return ossl_ec_scalar_mul_ladder(group, r, scalars[0], points[0],
                                             ctx);
        }
    }

    if (scalar != NULL) {
        generator = EC_GROUP_get0_generator(group);
        if (generator == NULL) {
            ERR_raise(ERR_LIB_EC, EC_R_UNDEFINED_GENERATOR);
            goto err;
        }

        

        pre_comp = group->pre_comp.ec;
        if (pre_comp && pre_comp->numblocks
            && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) ==
                0)) {
            blocksize = pre_comp->blocksize;

            
            numblocks = (BN_num_bits(scalar) / blocksize) + 1;

            
            if (numblocks > pre_comp->numblocks)
                numblocks = pre_comp->numblocks;

            pre_points_per_block = (size_t)1 << (pre_comp->w - 1);

            
            if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block)) {
                ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                goto err;
            }
        } else {
            
            pre_comp = NULL;
            numblocks = 1;
            num_scalar = 1;     
        }
    }

    totalnum = num + numblocks;

    wsize = OPENSSL_malloc(totalnum * sizeof(wsize[0]));
    wNAF_len = OPENSSL_malloc(totalnum * sizeof(wNAF_len[0]));
    
    wNAF = OPENSSL_malloc((totalnum + 1) * sizeof(wNAF[0]));
    val_sub = OPENSSL_malloc(totalnum * sizeof(val_sub[0]));

    
    if (wNAF != NULL)
        wNAF[0] = NULL;         

    if (wsize == NULL || wNAF_len == NULL || wNAF == NULL || val_sub == NULL)
        goto err;

    
    num_val = 0;

    for (i = 0; i < num + num_scalar; i++) {
        size_t bits;

        bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
        wsize[i] = EC_window_bits_for_scalar_size(bits);
        num_val += (size_t)1 << (wsize[i] - 1);
        wNAF[i + 1] = NULL;     
        wNAF[i] =
            bn_compute_wNAF((i < num ? scalars[i] : scalar), wsize[i],
                            &wNAF_len[i]);
        if (wNAF[i] == NULL)
            goto err;
        if (wNAF_len[i] > max_len)
            max_len = wNAF_len[i];
    }

    if (numblocks) {
        

        if (pre_comp == NULL) {
            if (num_scalar != 1) {
                ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                goto err;
            }
            
        } else {
            signed char *tmp_wNAF = NULL;
            size_t tmp_len = 0;

            if (num_scalar != 0) {
                ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                goto err;
            }

            
            wsize[num] = pre_comp->w;
            tmp_wNAF = bn_compute_wNAF(scalar, wsize[num], &tmp_len);
            if (!tmp_wNAF)
                goto err;

            if (tmp_len <= max_len) {
                

                numblocks = 1;
                totalnum = num + 1; 
                wNAF[num] = tmp_wNAF;
                wNAF[num + 1] = NULL;
                wNAF_len[num] = tmp_len;
                
                val_sub[num] = pre_comp->points;
            } else {
                

                signed char *pp;
                EC_POINT **tmp_points;

                if (tmp_len < numblocks * blocksize) {
                    
                    numblocks = (tmp_len + blocksize - 1) / blocksize;
                    if (numblocks > pre_comp->numblocks) {
                        ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                        OPENSSL_free(tmp_wNAF);
                        goto err;
                    }
                    totalnum = num + numblocks;
                }

                
                pp = tmp_wNAF;
                tmp_points = pre_comp->points;

                for (i = num; i < totalnum; i++) {
                    if (i < totalnum - 1) {
                        wNAF_len[i] = blocksize;
                        if (tmp_len < blocksize) {
                            ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                            OPENSSL_free(tmp_wNAF);
                            goto err;
                        }
                        tmp_len -= blocksize;
                    } else
                        
                        wNAF_len[i] = tmp_len;

                    wNAF[i + 1] = NULL;
                    wNAF[i] = OPENSSL_malloc(wNAF_len[i]);
                    if (wNAF[i] == NULL) {
                        OPENSSL_free(tmp_wNAF);
                        goto err;
                    }
                    memcpy(wNAF[i], pp, wNAF_len[i]);
                    if (wNAF_len[i] > max_len)
                        max_len = wNAF_len[i];

                    if (*tmp_points == NULL) {
                        ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                        OPENSSL_free(tmp_wNAF);
                        goto err;
                    }
                    val_sub[i] = tmp_points;
                    tmp_points += pre_points_per_block;
                    pp += blocksize;
                }
                OPENSSL_free(tmp_wNAF);
            }
        }
    }

    
    val = OPENSSL_malloc((num_val + 1) * sizeof(val[0]));
    if (val == NULL)
        goto err;
    val[num_val] = NULL;        

    
    v = val;
    for (i = 0; i < num + num_scalar; i++) {
        val_sub[i] = v;
        for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++) {
            *v = EC_POINT_new(group);
            if (*v == NULL)
                goto err;
            v++;
        }
    }
    if (!(v == val + num_val)) {
        ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
        goto err;
    }

    if ((tmp = EC_POINT_new(group)) == NULL)
        goto err;

    
    for (i = 0; i < num + num_scalar; i++) {
        if (i < num) {
            if (!EC_POINT_copy(val_sub[i][0], points[i]))
                goto err;
        } else {
            if (!EC_POINT_copy(val_sub[i][0], generator))
                goto err;
        }

        if (wsize[i] > 1) {
            if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx))
                goto err;
            for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++) {
                if (!EC_POINT_add
                    (group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx))
                    goto err;
            }
        }
    }

    if (group->meth->points_make_affine == NULL
        || !group->meth->points_make_affine(group, num_val, val, ctx))
        goto err;

    r_is_at_infinity = 1;

    for (k = max_len - 1; k >= 0; k--) {
        if (!r_is_at_infinity) {
            if (!EC_POINT_dbl(group, r, r, ctx))
                goto err;
        }

        for (i = 0; i < totalnum; i++) {
            if (wNAF_len[i] > (size_t)k) {
                int digit = wNAF[i][k];
                int is_neg;

                if (digit) {
                    is_neg = digit < 0;

                    if (is_neg)
                        digit = -digit;

                    if (is_neg != r_is_inverted) {
                        if (!r_is_at_infinity) {
                            if (!EC_POINT_invert(group, r, ctx))
                                goto err;
                        }
                        r_is_inverted = !r_is_inverted;
                    }

                    

                    if (r_is_at_infinity) {
                        if (!EC_POINT_copy(r, val_sub[i][digit >> 1]))
                            goto err;

                        
                        if (!ossl_ec_point_blind_coordinates(group, r, ctx)) {
                            ERR_raise(ERR_LIB_EC, EC_R_POINT_COORDINATES_BLIND_FAILURE);
                            goto err;
                        }

                        r_is_at_infinity = 0;
                    } else {
                        if (!EC_POINT_add
                            (group, r, r, val_sub[i][digit >> 1], ctx))
                            goto err;
                    }
                }
            }
        }
    }

    if (r_is_at_infinity) {
        if (!EC_POINT_set_to_infinity(group, r))
            goto err;
    } else {
        if (r_is_inverted)
            if (!EC_POINT_invert(group, r, ctx))
                goto err;
    }

    ret = 1;

 err:
    EC_POINT_free(tmp);
    OPENSSL_free(wsize);
    OPENSSL_free(wNAF_len);
    if (wNAF != NULL) {
        signed char **w;

        for (w = wNAF; *w != NULL; w++)
            OPENSSL_free(*w);

        OPENSSL_free(wNAF);
    }
    if (val != NULL) {
        for (v = val; *v != NULL; v++)
            EC_POINT_clear_free(*v);

        OPENSSL_free(val);
    }
    OPENSSL_free(val_sub);
    return ret;
}


int ossl_ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
{
    const EC_POINT *generator;
    EC_POINT *tmp_point = NULL, *base = NULL, **var;
    const BIGNUM *order;
    size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num;
    EC_POINT **points = NULL;
    EC_PRE_COMP *pre_comp;
    int ret = 0;
    int used_ctx = 0;
#ifndef FIPS_MODULE
    BN_CTX *new_ctx = NULL;
#endif

    
    EC_pre_comp_free(group);
    if ((pre_comp = ec_pre_comp_new(group)) == NULL)
        return 0;

    generator = EC_GROUP_get0_generator(group);
    if (generator == NULL) {
        ERR_raise(ERR_LIB_EC, EC_R_UNDEFINED_GENERATOR);
        goto err;
    }

#ifndef FIPS_MODULE
    if (ctx == NULL)
        ctx = new_ctx = BN_CTX_new();
#endif
    if (ctx == NULL)
        goto err;

    BN_CTX_start(ctx);
    used_ctx = 1;

    order = EC_GROUP_get0_order(group);
    if (order == NULL)
        goto err;
    if (BN_is_zero(order)) {
        ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_ORDER);
        goto err;
    }

    bits = BN_num_bits(order);
    
    blocksize = 8;
    w = 4;
    if (EC_window_bits_for_scalar_size(bits) > w) {
        
        w = EC_window_bits_for_scalar_size(bits);
    }

    numblocks = (bits + blocksize - 1) / blocksize; 

    pre_points_per_block = (size_t)1 << (w - 1);
    num = pre_points_per_block * numblocks; 

    points = OPENSSL_malloc(sizeof(*points) * (num + 1));
    if (points == NULL)
        goto err;

    var = points;
    var[num] = NULL;            
    for (i = 0; i < num; i++) {
        if ((var[i] = EC_POINT_new(group)) == NULL) {
            ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
            goto err;
        }
    }

    if ((tmp_point = EC_POINT_new(group)) == NULL
        || (base = EC_POINT_new(group)) == NULL) {
        ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
        goto err;
    }

    if (!EC_POINT_copy(base, generator))
        goto err;

    
    for (i = 0; i < numblocks; i++) {
        size_t j;

        if (!EC_POINT_dbl(group, tmp_point, base, ctx))
            goto err;

        if (!EC_POINT_copy(*var++, base))
            goto err;

        for (j = 1; j < pre_points_per_block; j++, var++) {
            
            if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx))
                goto err;
        }

        if (i < numblocks - 1) {
            
            size_t k;

            if (blocksize <= 2) {
                ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
                goto err;
            }

            if (!EC_POINT_dbl(group, base, tmp_point, ctx))
                goto err;
            for (k = 2; k < blocksize; k++) {
                if (!EC_POINT_dbl(group, base, base, ctx))
                    goto err;
            }
        }
    }

    if (group->meth->points_make_affine == NULL
        || !group->meth->points_make_affine(group, num, points, ctx))
        goto err;

    pre_comp->group = group;
    pre_comp->blocksize = blocksize;
    pre_comp->numblocks = numblocks;
    pre_comp->w = w;
    pre_comp->points = points;
    points = NULL;
    pre_comp->num = num;
    SETPRECOMP(group, ec, pre_comp);
    pre_comp = NULL;
    ret = 1;

 err:
    if (used_ctx)
        BN_CTX_end(ctx);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    EC_ec_pre_comp_free(pre_comp);
    if (points) {
        EC_POINT **p;

        for (p = points; *p != NULL; p++)
            EC_POINT_free(*p);
        OPENSSL_free(points);
    }
    EC_POINT_free(tmp_point);
    EC_POINT_free(base);
    return ret;
}

int ossl_ec_wNAF_have_precompute_mult(const EC_GROUP *group)
{
    return HAVEPRECOMP(group, ec);
}
