int
BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
{
int ret = 0;
BIGNUM *Ri, *R;
BN_CTX_start(ctx);
if ((Ri = BN_CTX_get(ctx)) == NULL)
goto err;
R = &(mont->RR); /* grab RR as a temp */
if (!BN_copy(&(mont->N), mod))
goto err; /* Set N */
mont->N.neg = 0;
#ifdef MONT_WORD
{
BIGNUM tmod;
BN_ULONG buf[2];
BN_init(&tmod);
tmod.d = buf;
tmod.dmax = 2;
tmod.neg = 0;
mont->ri = (BN_num_bits(mod) +
(BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2;
#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
/* Only certain BN_BITS2<=32 platforms actually make use of
* n0[1], and we could use the #else case (with a shorter R
* value) for the others. However, currently only the assembler
* files do know which is which. */
BN_zero(R);
if (!(BN_set_bit(R, 2 * BN_BITS2)))
goto err;
tmod.top = 0;
if ((buf[0] = mod->d[0]))
tmod.top = 1;
if ((buf[1] = mod->top > 1 ? mod->d[1] : 0))
tmod.top = 2;
if ((BN_mod_inverse_ct(Ri, R, &tmod, ctx)) == NULL)
goto err;
if (!BN_lshift(Ri, Ri, 2 * BN_BITS2))
goto err; /* R*Ri */
if (!BN_is_zero(Ri)) {
if (!BN_sub_word(Ri, 1))
goto err;
}
else /* if N mod word size == 1 */
{
if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL)
goto err;
/* Ri-- (mod double word size) */
Ri->neg = 0;
Ri->d[0] = BN_MASK2;
Ri->d[1] = BN_MASK2;
Ri->top = 2;
}
if (!BN_div_ct(Ri, NULL, Ri, &tmod, ctx))
goto err;
/* Ni = (R*Ri-1)/N,
* keep only couple of least significant words: */
mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;
#else
BN_zero(R);
if (!(BN_set_bit(R, BN_BITS2)))
goto err; /* R */
buf[0] = mod->d[0]; /* tmod = N mod word size */
buf[1] = 0;
tmod.top = buf[0] != 0 ? 1 : 0;
/* Ri = R^-1 mod N*/
if ((BN_mod_inverse_ct(Ri, R, &tmod, ctx)) == NULL)
goto err;
if (!BN_lshift(Ri, Ri, BN_BITS2))
goto err; /* R*Ri */
if (!BN_is_zero(Ri)) {
if (!BN_sub_word(Ri, 1))
goto err;
}
else /* if N mod word size == 1 */
{
if (!BN_set_word(Ri, BN_MASK2))
goto err; /* Ri-- (mod word size) */
}
if (!BN_div_ct(Ri, NULL, Ri, &tmod, ctx))
goto err;
/* Ni = (R*Ri-1)/N,
* keep only least significant word: */
mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
mont->n0[1] = 0;
#endif
}
#else /* !MONT_WORD */
{ /* bignum version */
mont->ri = BN_num_bits(&mont->N);
BN_zero(R);
if (!BN_set_bit(R, mont->ri))
goto err; /* R = 2^ri */
/* Ri = R^-1 mod N*/
if ((BN_mod_inverse_ct(Ri, R, &mont->N, ctx)) == NULL)
goto err;
if (!BN_lshift(Ri, Ri, mont->ri))
goto err; /* R*Ri */
if (!BN_sub_word(Ri, 1))
goto err;
/* Ni = (R*Ri-1) / N */
if (!BN_div_ct(&(mont->Ni), NULL, Ri, &mont->N, ctx))
goto err;
}
#endif
/* setup RR for conversions */
BN_zero(&(mont->RR));
if (!BN_set_bit(&(mont->RR), mont->ri*2))
goto err;
if (!BN_mod_ct(&(mont->RR), &(mont->RR), &(mont->N), ctx))
goto err;
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
static int
ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
{
BN_CTX *ctx = NULL;
BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
EC_POINT *tmp_point = NULL;
const EC_GROUP *group;
int ret = 0;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
ECDSAerror(ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (ctx_in == NULL) {
if ((ctx = BN_CTX_new()) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
return 0;
}
} else
ctx = ctx_in;
k = BN_new(); /* this value is later returned in *kinvp */
r = BN_new(); /* this value is later returned in *rp */
order = BN_new();
X = BN_new();
if (!k || !r || !order || !X) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
if ((tmp_point = EC_POINT_new(group)) == NULL) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
do {
/* get random k */
do
if (!BN_rand_range(k, order)) {
ECDSAerror(ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
while (BN_is_zero(k));
/* We do not want timing information to leak the length of k,
* so we compute G*k using an equivalent scalar of fixed
* bit-length. */
if (!BN_add(k, k, order))
goto err;
if (BN_num_bits(k) <= BN_num_bits(order))
if (!BN_add(k, k, order))
goto err;
BN_set_flags(k, BN_FLG_CONSTTIME);
/* compute r the x-coordinate of generator * k */
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
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_point, X, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
}
#ifndef OPENSSL_NO_EC2M
else /* NID_X9_62_characteristic_two_field */
{
if (!EC_POINT_get_affine_coordinates_GF2m(group,
tmp_point, X, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
}
#endif
if (!BN_nnmod(r, X, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
} while (BN_is_zero(r));
/* compute the inverse of k */
if (!BN_mod_inverse_ct(k, k, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* clear old values if necessary */
BN_clear_free(*rp);
BN_clear_free(*kinvp);
/* save the pre-computed values */
*rp = r;
*kinvp = k;
ret = 1;
err:
if (!ret) {
BN_clear_free(k);
BN_clear_free(r);
}
if (ctx_in == NULL)
BN_CTX_free(ctx);
BN_free(order);
EC_POINT_free(tmp_point);
BN_clear_free(X);
return (ret);
}
static int
ecdsa_do_verify(const unsigned char *dgst, int dgst_len, const ECDSA_SIG *sig,
EC_KEY *eckey)
{
int ret = -1, i;
BN_CTX *ctx;
BIGNUM *order, *u1, *u2, *m, *X;
EC_POINT *point = NULL;
const EC_GROUP *group;
const EC_POINT *pub_key;
/* check input values */
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
(pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) {
ECDSAerror(ECDSA_R_MISSING_PARAMETERS);
return -1;
}
ctx = BN_CTX_new();
if (!ctx) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
return -1;
}
BN_CTX_start(ctx);
order = BN_CTX_get(ctx);
u1 = BN_CTX_get(ctx);
u2 = BN_CTX_get(ctx);
m = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
if (!X) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) {
ECDSAerror(ECDSA_R_BAD_SIGNATURE);
ret = 0; /* signature is invalid */
goto err;
}
/* calculate tmp1 = inv(S) mod order */
if (!BN_mod_inverse_ct(u2, sig->s, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* digest -> m */
i = BN_num_bits(order);
/* Need to truncate digest if it is too long: first truncate whole
* bytes.
*/
if (8 * dgst_len > i)
dgst_len = (i + 7)/8;
if (!BN_bin2bn(dgst, dgst_len, m)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* If still too long truncate remaining bits with a shift */
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* u1 = m * tmp mod order */
if (!BN_mod_mul(u1, m, u2, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* u2 = r * w mod q */
if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
if ((point = EC_POINT_new(group)) == NULL) {
ECDSAerror(ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
NID_X9_62_prime_field) {
if (!EC_POINT_get_affine_coordinates_GFp(group,
point, X, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
}
#ifndef OPENSSL_NO_EC2M
else /* NID_X9_62_characteristic_two_field */
{
if (!EC_POINT_get_affine_coordinates_GF2m(group,
point, X, NULL, ctx)) {
ECDSAerror(ERR_R_EC_LIB);
goto err;
}
}
#endif
if (!BN_nnmod(u1, X, order, ctx)) {
ECDSAerror(ERR_R_BN_LIB);
goto err;
}
/* if the signature is correct u1 is equal to sig->r */
ret = (BN_ucmp(u1, sig->r) == 0);
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
EC_POINT_free(point);
return ret;
}
int
ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP * group, const EC_POINT * point,
BIGNUM * x, BIGNUM * y, BN_CTX * ctx)
{
BN_CTX *new_ctx = NULL;
BIGNUM *Z, *Z_1, *Z_2, *Z_3;
const BIGNUM *Z_;
int ret = 0;
if (EC_POINT_is_at_infinity(group, point) > 0) {
ECerror(EC_R_POINT_AT_INFINITY);
return 0;
}
if (ctx == NULL) {
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
return 0;
}
BN_CTX_start(ctx);
if ((Z = BN_CTX_get(ctx)) == NULL)
goto err;
if ((Z_1 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((Z_2 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((Z_3 = BN_CTX_get(ctx)) == NULL)
goto err;
/* transform (X, Y, Z) into (x, y) := (X/Z^2, Y/Z^3) */
if (group->meth->field_decode) {
if (!group->meth->field_decode(group, Z, &point->Z, ctx))
goto err;
Z_ = Z;
} else {
Z_ = &point->Z;
}
if (BN_is_one(Z_)) {
if (group->meth->field_decode) {
if (x != NULL) {
if (!group->meth->field_decode(group, x, &point->X, ctx))
goto err;
}
if (y != NULL) {
if (!group->meth->field_decode(group, y, &point->Y, ctx))
goto err;
}
} else {
if (x != NULL) {
if (!BN_copy(x, &point->X))
goto err;
}
if (y != NULL) {
if (!BN_copy(y, &point->Y))
goto err;
}
}
} else {
if (!BN_mod_inverse_ct(Z_1, Z_, &group->field, ctx)) {
ECerror(ERR_R_BN_LIB);
goto err;
}
if (group->meth->field_encode == 0) {
/* field_sqr works on standard representation */
if (!group->meth->field_sqr(group, Z_2, Z_1, ctx))
goto err;
} else {
if (!BN_mod_sqr(Z_2, Z_1, &group->field, ctx))
goto err;
}
if (x != NULL) {
/*
* in the Montgomery case, field_mul will cancel out
* Montgomery factor in X:
*/
if (!group->meth->field_mul(group, x, &point->X, Z_2, ctx))
goto err;
}
if (y != NULL) {
if (group->meth->field_encode == 0) {
/* field_mul works on standard representation */
if (!group->meth->field_mul(group, Z_3, Z_2, Z_1, ctx))
goto err;
} else {
if (!BN_mod_mul(Z_3, Z_2, Z_1, &group->field, ctx))
goto err;
}
/*
* in the Montgomery case, field_mul will cancel out
* Montgomery factor in Y:
*/
if (!group->meth->field_mul(group, y, &point->Y, Z_3, ctx))
goto err;
}
}
ret = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
return ret;
}
int
ec_GFp_simple_points_make_affine(const EC_GROUP * group, size_t num, EC_POINT * points[], BN_CTX * ctx)
{
BN_CTX *new_ctx = NULL;
BIGNUM *tmp0, *tmp1;
size_t pow2 = 0;
BIGNUM **heap = NULL;
size_t i;
int ret = 0;
if (num == 0)
return 1;
if (ctx == NULL) {
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
return 0;
}
BN_CTX_start(ctx);
if ((tmp0 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((tmp1 = BN_CTX_get(ctx)) == NULL)
goto err;
/*
* Before converting the individual points, compute inverses of all Z
* values. Modular inversion is rather slow, but luckily we can do
* with a single explicit inversion, plus about 3 multiplications per
* input value.
*/
pow2 = 1;
while (num > pow2)
pow2 <<= 1;
/*
* Now pow2 is the smallest power of 2 satifsying pow2 >= num. We
* need twice that.
*/
pow2 <<= 1;
heap = reallocarray(NULL, pow2, sizeof heap[0]);
if (heap == NULL)
goto err;
/*
* The array is used as a binary tree, exactly as in heapsort:
*
* heap[1] heap[2] heap[3] heap[4] heap[5]
* heap[6] heap[7] heap[8]heap[9] heap[10]heap[11]
* heap[12]heap[13] heap[14] heap[15]
*
* We put the Z's in the last line; then we set each other node to the
* product of its two child-nodes (where empty or 0 entries are
* treated as ones); then we invert heap[1]; then we invert each
* other node by replacing it by the product of its parent (after
* inversion) and its sibling (before inversion).
*/
heap[0] = NULL;
for (i = pow2 / 2 - 1; i > 0; i--)
heap[i] = NULL;
for (i = 0; i < num; i++)
heap[pow2 / 2 + i] = &points[i]->Z;
for (i = pow2 / 2 + num; i < pow2; i++)
heap[i] = NULL;
/* set each node to the product of its children */
for (i = pow2 / 2 - 1; i > 0; i--) {
heap[i] = BN_new();
if (heap[i] == NULL)
goto err;
if (heap[2 * i] != NULL) {
if ((heap[2 * i + 1] == NULL) || BN_is_zero(heap[2 * i + 1])) {
if (!BN_copy(heap[i], heap[2 * i]))
goto err;
} else {
if (BN_is_zero(heap[2 * i])) {
if (!BN_copy(heap[i], heap[2 * i + 1]))
goto err;
} else {
if (!group->meth->field_mul(group, heap[i],
heap[2 * i], heap[2 * i + 1], ctx))
goto err;
}
}
}
}
/* invert heap[1] */
if (!BN_is_zero(heap[1])) {
if (!BN_mod_inverse_ct(heap[1], heap[1], &group->field, ctx)) {
ECerror(ERR_R_BN_LIB);
goto err;
}
}
if (group->meth->field_encode != 0) {
/*
* in the Montgomery case, we just turned R*H (representing
* H) into 1/(R*H), but we need R*(1/H) (representing
* 1/H); i.e. we have need to multiply by the Montgomery
* factor twice
*/
if (!group->meth->field_encode(group, heap[1], heap[1], ctx))
goto err;
if (!group->meth->field_encode(group, heap[1], heap[1], ctx))
goto err;
}
/* set other heap[i]'s to their inverses */
for (i = 2; i < pow2 / 2 + num; i += 2) {
/* i is even */
if ((heap[i + 1] != NULL) && !BN_is_zero(heap[i + 1])) {
if (!group->meth->field_mul(group, tmp0, heap[i / 2], heap[i + 1], ctx))
goto err;
if (!group->meth->field_mul(group, tmp1, heap[i / 2], heap[i], ctx))
goto err;
if (!BN_copy(heap[i], tmp0))
goto err;
if (!BN_copy(heap[i + 1], tmp1))
goto err;
} else {
if (!BN_copy(heap[i], heap[i / 2]))
goto err;
}
}
/*
* we have replaced all non-zero Z's by their inverses, now fix up
* all the points
*/
for (i = 0; i < num; i++) {
EC_POINT *p = points[i];
if (!BN_is_zero(&p->Z)) {
/* turn (X, Y, 1/Z) into (X/Z^2, Y/Z^3, 1) */
if (!group->meth->field_sqr(group, tmp1, &p->Z, ctx))
goto err;
if (!group->meth->field_mul(group, &p->X, &p->X, tmp1, ctx))
goto err;
if (!group->meth->field_mul(group, tmp1, tmp1, &p->Z, ctx))
goto err;
if (!group->meth->field_mul(group, &p->Y, &p->Y, tmp1, ctx))
goto err;
if (group->meth->field_set_to_one != 0) {
if (!group->meth->field_set_to_one(group, &p->Z, ctx))
goto err;
} else {
if (!BN_one(&p->Z))
goto err;
}
p->Z_is_one = 1;
}
}
ret = 1;
err:
BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
if (heap != NULL) {
/*
* heap[pow2/2] .. heap[pow2-1] have not been allocated
* locally!
*/
for (i = pow2 / 2 - 1; i > 0; i--) {
BN_clear_free(heap[i]);
}
free(heap);
}
return ret;
}
int
BN_X931_derive_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2, const BIGNUM *Xp,
const BIGNUM *Xp1, const BIGNUM *Xp2, const BIGNUM *e, BN_CTX *ctx,
BN_GENCB *cb)
{
int ret = 0;
BIGNUM *t, *p1p2, *pm1;
/* Only even e supported */
if (!BN_is_odd(e))
return 0;
BN_CTX_start(ctx);
if (p1 == NULL) {
if ((p1 = BN_CTX_get(ctx)) == NULL)
goto err;
}
if (p2 == NULL) {
if ((p2 = BN_CTX_get(ctx)) == NULL)
goto err;
}
if ((t = BN_CTX_get(ctx)) == NULL)
goto err;
if ((p1p2 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((pm1 = BN_CTX_get(ctx)) == NULL)
goto err;
if (!bn_x931_derive_pi(p1, Xp1, ctx, cb))
goto err;
if (!bn_x931_derive_pi(p2, Xp2, ctx, cb))
goto err;
if (!BN_mul(p1p2, p1, p2, ctx))
goto err;
/* First set p to value of Rp */
if (!BN_mod_inverse_ct(p, p2, p1, ctx))
goto err;
if (!BN_mul(p, p, p2, ctx))
goto err;
if (!BN_mod_inverse_ct(t, p1, p2, ctx))
goto err;
if (!BN_mul(t, t, p1, ctx))
goto err;
if (!BN_sub(p, p, t))
goto err;
if (p->neg && !BN_add(p, p, p1p2))
goto err;
/* p now equals Rp */
if (!BN_mod_sub(p, p, Xp, p1p2, ctx))
goto err;
if (!BN_add(p, p, Xp))
goto err;
/* p now equals Yp0 */
for (;;) {
int i = 1;
BN_GENCB_call(cb, 0, i++);
if (!BN_copy(pm1, p))
goto err;
if (!BN_sub_word(pm1, 1))
goto err;
if (!BN_gcd_ct(t, pm1, e, ctx))
goto err;
if (BN_is_one(t)
/* X9.31 specifies 8 MR and 1 Lucas test or any prime test
* offering similar or better guarantees 50 MR is considerably
* better.
*/
&& BN_is_prime_fasttest_ex(p, 50, ctx, 1, cb))
break;
if (!BN_add(p, p, p1p2))
goto err;
}
BN_GENCB_call(cb, 3, 0);
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
