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Update pre9

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This commit is contained in:
Hakase
2018-07-19 21:47:35 +09:00
parent 1914ae9055
commit 46f6b5e2fe
84 changed files with 2388 additions and 962 deletions
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crypto/ec/ec_mult.c
+114 -81
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@@ -108,10 +108,9 @@ void EC_ec_pre_comp_free(EC_PRE_COMP *pre)
} while(0)
/*-
* This functions computes (in constant time) a point multiplication over the
* EC group.
*
* At a high level, it is Montgomery ladder with conditional swaps.
* This functions computes a single point multiplication over the EC group,
* using, at a high level, a Montgomery ladder with conditional swaps, with
* various timing attack defenses.
*
* It performs either a fixed point multiplication
* (scalar * generator)
@@ -119,51 +118,85 @@ void EC_ec_pre_comp_free(EC_PRE_COMP *pre)
* (scalar * point)
* when point is not NULL.
*
* scalar should be in the range [0,n) otherwise all constant time bets are off.
* `scalar` cannot be NULL and should be in the range [0,n) otherwise all
* constant time bets are off (where n is the cardinality of the EC group).
*
* NB: This says nothing about EC_POINT_add and EC_POINT_dbl,
* which of course are not constant time themselves.
* This function expects `group->order` and `group->cardinality` to be well
* defined and non-zero: it fails with an error code otherwise.
*
* The product is stored in r.
* NB: This says nothing about the constant-timeness of the ladder step
* implementation (i.e., the default implementation is based on EC_POINT_add and
* EC_POINT_dbl, which of course are not constant time themselves) or the
* underlying multiprecision arithmetic.
*
* The product is stored in `r`.
*
* This is an internal function: callers are in charge of ensuring that the
* input parameters `group`, `r`, `scalar` and `ctx` are not NULL.
*
* Returns 1 on success, 0 otherwise.
*/
static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, const EC_POINT *point,
BN_CTX *ctx)
int 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;
BN_CTX *new_ctx = NULL;
int ret = 0;
if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
/* early exit if the input point is the point at infinity */
if (point != NULL && EC_POINT_is_at_infinity(group, point))
return EC_POINT_set_to_infinity(group, r);
if (BN_is_zero(group->order)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, EC_R_UNKNOWN_ORDER);
return 0;
}
if (BN_is_zero(group->cofactor)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, EC_R_UNKNOWN_COFACTOR);
return 0;
}
BN_CTX_start(ctx);
s = EC_POINT_new(group);
if (s == NULL)
if (((p = EC_POINT_new(group)) == NULL)
|| ((s = EC_POINT_new(group)) == NULL)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_MALLOC_FAILURE);
goto err;
if (point == NULL) {
if (!EC_POINT_copy(s, group->generator))
goto err;
} else {
if (!EC_POINT_copy(s, point))
goto err;
}
if (point == NULL) {
if (!EC_POINT_copy(p, group->generator)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_EC_LIB);
goto err;
}
} else {
if (!EC_POINT_copy(p, point)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, 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 || !BN_mul(cardinality, group->order, group->cofactor, ctx))
if (k == NULL) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!BN_mul(cardinality, group->order, group->cofactor, ctx)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
/*
* Group cardinalities are often on a word boundary.
@@ -174,11 +207,15 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
cardinality_bits = BN_num_bits(cardinality);
group_top = bn_get_top(cardinality);
if ((bn_wexpand(k, group_top + 1) == NULL)
|| (bn_wexpand(lambda, group_top + 1) == NULL))
|| (bn_wexpand(lambda, group_top + 1) == NULL)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
if (!BN_copy(k, scalar))
if (!BN_copy(k, scalar)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
BN_set_flags(k, BN_FLG_CONSTTIME);
@@ -187,15 +224,21 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
* this is an unusual input, and we don't guarantee
* constant-timeness
*/
if (!BN_nnmod(k, k, cardinality, ctx))
if (!BN_nnmod(k, k, cardinality, ctx)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
}
if (!BN_add(lambda, k, cardinality))
if (!BN_add(lambda, k, cardinality)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
BN_set_flags(lambda, BN_FLG_CONSTTIME);
if (!BN_add(k, lambda, cardinality))
if (!BN_add(k, lambda, cardinality)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
/*
* lambda := scalar + cardinality
* k := scalar + 2*cardinality
@@ -209,8 +252,13 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
|| (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(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)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB);
goto err;
}
/*-
* Apply coordinate blinding for EC_POINT.
@@ -220,19 +268,19 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
* success or if coordinate blinding is not implemented for this
* group.
*/
if (!ec_point_blind_coordinates(group, s, ctx))
if (!ec_point_blind_coordinates(group, p, ctx)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, EC_R_POINT_COORDINATES_BLIND_FAILURE);
goto err;
}
/* Initialize the Montgomery ladder */
if (!ec_point_ladder_pre(group, r, s, p, ctx)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, EC_R_LADDER_PRE_FAILURE);
goto err;
}
/* top bit is a 1, in a fixed pos */
if (!EC_POINT_copy(r, s))
goto err;
EC_POINT_BN_set_flags(r, BN_FLG_CONSTTIME);
if (!EC_POINT_dbl(group, s, s, ctx))
goto err;
pbit = 0;
pbit = 1;
#define EC_POINT_CSWAP(c, a, b, w, t) do { \
BN_consttime_swap(c, (a)->X, (b)->X, w); \
@@ -304,10 +352,12 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
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_add(group, s, r, s, ctx))
goto err;
if (!EC_POINT_dbl(group, r, r, ctx))
/* Perform a single step of the Montgomery ladder */
if (!ec_point_ladder_step(group, r, s, p, ctx)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, EC_R_LADDER_STEP_FAILURE);
goto err;
}
/*
* pbit logic merges this cswap with that of the
* next iteration
@@ -318,12 +368,18 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r,
EC_POINT_CSWAP(pbit, r, s, group_top, Z_is_one);
#undef EC_POINT_CSWAP
/* Finalize ladder (and recover full point coordinates) */
if (!ec_point_ladder_post(group, r, s, p, ctx)) {
ECerr(EC_F_EC_SCALAR_MUL_LADDER, EC_R_LADDER_POST_FAILURE);
goto err;
}
ret = 1;
err:
EC_POINT_free(p);
EC_POINT_free(s);
BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
return ret;
}
@@ -355,7 +411,6 @@ int 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)
{
BN_CTX *new_ctx = NULL;
const EC_POINT *generator = NULL;
EC_POINT *tmp = NULL;
size_t totalnum;
@@ -380,56 +435,35 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
* precomputation is not available */
int ret = 0;
if (!ec_point_is_compat(r, group)) {
ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if ((scalar == NULL) && (num == 0)) {
return EC_POINT_set_to_infinity(group, r);
}
if (!BN_is_zero(group->order) && !BN_is_zero(group->cofactor)) {
/*-
* Handle the common cases where the scalar is secret, enforcing a constant
* time scalar multiplication algorithm.
* Handle the common cases where the scalar is secret, enforcing a
* scalar multiplication implementation based on a Montgomery ladder,
* with various timing attack defenses.
*/
if ((scalar != NULL) && (num == 0)) {
/*-
* In this case we want to compute scalar * GeneratorPoint: this
* codepath is reached most prominently by (ephemeral) key generation
* of EC cryptosystems (i.e. ECDSA keygen and sign setup, ECDH
* keygen/first half), where the scalar is always secret. This is why
* we ignore if BN_FLG_CONSTTIME is actually set and we always call the
* constant time version.
* codepath is reached most prominently by (ephemeral) key
* generation of EC cryptosystems (i.e. ECDSA keygen and sign setup,
* ECDH keygen/first half), where the scalar is always secret. This
* is why we ignore if BN_FLG_CONSTTIME is actually set and we
* always call the ladder version.
*/
return ec_mul_consttime(group, r, scalar, NULL, ctx);
return ec_scalar_mul_ladder(group, r, scalar, NULL, ctx);
}
if ((scalar == NULL) && (num == 1)) {
/*-
* In this case we want to compute scalar * GenericPoint: this codepath
* is reached most prominently by the second half of ECDH, where the
* secret scalar is multiplied by the peer's public point. To protect
* the secret scalar, we ignore if BN_FLG_CONSTTIME is actually set and
* we always call the constant time version.
* In this case we want to compute scalar * VariablePoint: this
* codepath is reached most prominently by the second half of ECDH,
* where the secret scalar is multiplied by the peer's public point.
* To protect the secret scalar, we ignore if BN_FLG_CONSTTIME is
* actually set and we always call the ladder version.
*/
return ec_mul_consttime(group, r, scalars[0], points[0], ctx);
return ec_scalar_mul_ladder(group, r, scalars[0], points[0], ctx);
}
}
for (i = 0; i < num; i++) {
if (!ec_point_is_compat(points[i], group)) {
ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
}
if (ctx == NULL) {
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
}
if (scalar != NULL) {
generator = EC_GROUP_get0_generator(group);
if (generator == NULL) {
@@ -736,7 +770,6 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
ret = 1;
err:
BN_CTX_free(new_ctx);
EC_POINT_free(tmp);
OPENSSL_free(wsize);
OPENSSL_free(wNAF_len);