diff options
Diffstat (limited to 'openssl/crypto/ec/ecp_nistz256.c')
| -rwxr-xr-x | openssl/crypto/ec/ecp_nistz256.c | 135 |
1 files changed, 85 insertions, 50 deletions
diff --git a/openssl/crypto/ec/ecp_nistz256.c b/openssl/crypto/ec/ecp_nistz256.c index 2cd6599d8..ca44d0aae 100755 --- a/openssl/crypto/ec/ecp_nistz256.c +++ b/openssl/crypto/ec/ecp_nistz256.c @@ -222,6 +222,18 @@ static BN_ULONG is_one(const BN_ULONG a[P256_LIMBS]) return is_zero(res); } +static int ecp_nistz256_set_words(BIGNUM *a, BN_ULONG words[P256_LIMBS]) + { + if (bn_wexpand(a, P256_LIMBS) == NULL) { + ECerr(EC_F_ECP_NISTZ256_SET_WORDS, ERR_R_MALLOC_FAILURE); + return 0; + } + memcpy(a->d, words, sizeof(BN_ULONG) * P256_LIMBS); + a->top = P256_LIMBS; + bn_correct_top(a); + return 1; +} + #ifndef ECP_NISTZ256_REFERENCE_IMPLEMENTATION void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a); void ecp_nistz256_point_add(P256_POINT *r, @@ -557,13 +569,14 @@ static int ecp_nistz256_bignum_to_field_elem(BN_ULONG out[P256_LIMBS], } /* r = sum(scalar[i]*point[i]) */ -static void ecp_nistz256_windowed_mul(const EC_GROUP *group, +static int ecp_nistz256_windowed_mul(const EC_GROUP *group, P256_POINT *r, const BIGNUM **scalar, const EC_POINT **point, int num, BN_CTX *ctx) { - int i, j; + + int i, j, ret = 0; unsigned int index; unsigned char (*p_str)[33] = NULL; const unsigned int window_size = 5; @@ -589,6 +602,7 @@ static void ecp_nistz256_windowed_mul(const EC_GROUP *group, for (i = 0; i < num; i++) { P256_POINT *row = table[i]; + /* This is an unusual input, we don't guarantee constant-timeness. */ if ((BN_num_bits(scalar[i]) > 256) || BN_is_negative(scalar[i])) { BIGNUM *mod; @@ -697,6 +711,7 @@ static void ecp_nistz256_windowed_mul(const EC_GROUP *group, ecp_nistz256_point_add(r, r, &h); } + ret = 1; err: if (table_storage) OPENSSL_free(table_storage); @@ -704,6 +719,7 @@ static void ecp_nistz256_windowed_mul(const EC_GROUP *group, OPENSSL_free(p_str); if (scalars) OPENSSL_free(scalars); + return ret; } /* Coordinates of G, for which we have precomputed tables */ @@ -742,6 +758,7 @@ static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx) EC_POINT *P = NULL, *T = NULL; const EC_POINT *generator; EC_PRE_COMP *pre_comp; + BN_CTX *new_ctx = NULL; int i, j, k, ret = 0; size_t w; @@ -771,7 +788,7 @@ static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx) return 0; if (ctx == NULL) { - ctx = BN_CTX_new(); + ctx = new_ctx = BN_CTX_new(); if (ctx == NULL) goto err; } @@ -802,30 +819,41 @@ static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx) P = EC_POINT_new(group); T = EC_POINT_new(group); + if (P == NULL || T == NULL) + goto err; /* * The zero entry is implicitly infinity, and we skip it, storing other * values with -1 offset. */ - EC_POINT_copy(T, generator); + if (!EC_POINT_copy(T, generator)) + goto err; for (k = 0; k < 64; k++) { - EC_POINT_copy(P, T); + if (!EC_POINT_copy(P, T)) + goto err; for (j = 0; j < 37; j++) { /* - * It would be faster to use - * ec_GFp_simple_points_make_affine and make multiple - * points affine at the same time. + * It would be faster to use EC_POINTs_make_affine and + * make multiple points affine at the same time. */ - ec_GFp_simple_make_affine(group, P, ctx); - ecp_nistz256_bignum_to_field_elem(preComputedTable[j] - [k].X, &P->X); - ecp_nistz256_bignum_to_field_elem(preComputedTable[j] - [k].Y, &P->Y); - for (i = 0; i < 7; i++) - ec_GFp_simple_dbl(group, P, P, ctx); + if (!EC_POINT_make_affine(group, P, ctx)) + goto err; + if (!ecp_nistz256_bignum_to_field_elem(preComputedTable[j][k].X, + &P->X) || + !ecp_nistz256_bignum_to_field_elem(preComputedTable[j][k].Y, + &P->Y)) { + ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, + EC_R_COORDINATES_OUT_OF_RANGE); + goto err; + } + for (i = 0; i < 7; i++) { + if (!EC_POINT_dbl(group, P, P, ctx)) + goto err; + } } - ec_GFp_simple_add(group, T, T, generator, ctx); + if (!EC_POINT_add(group, T, T, generator, ctx)) + goto err; } pre_comp->group = group; @@ -849,6 +877,8 @@ static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx) err: if (ctx != NULL) BN_CTX_end(ctx); + BN_CTX_free(new_ctx); + if (pre_comp) ecp_nistz256_pre_comp_free(pre_comp); if (precomp_storage) @@ -1102,6 +1132,9 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, const EC_PRE_COMP *pre_comp = NULL; const EC_POINT *generator = NULL; unsigned int index = 0; + BN_CTX *new_ctx = NULL; + const BIGNUM **new_scalars = NULL; + const EC_POINT **new_points = NULL; const unsigned int window_size = 7; const unsigned int mask = (1 << (window_size + 1)) - 1; unsigned int wvalue; @@ -1115,6 +1148,7 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS); return 0; } + if ((scalar == NULL) && (num == 0)) return EC_POINT_set_to_infinity(group, r); @@ -1125,13 +1159,13 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, } } - /* Need 256 bits for space for all coordinates. */ - bn_wexpand(&r->X, P256_LIMBS); - bn_wexpand(&r->Y, P256_LIMBS); - bn_wexpand(&r->Z, P256_LIMBS); - r->X.top = P256_LIMBS; - r->Y.top = P256_LIMBS; - r->Z.top = P256_LIMBS; + if (ctx == NULL) { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + } + + BN_CTX_start(ctx); if (scalar) { generator = EC_GROUP_get0_generator(group); @@ -1156,8 +1190,10 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, goto err; if (!ecp_nistz256_set_from_affine - (pre_comp_generator, group, pre_comp->precomp[0], ctx)) + (pre_comp_generator, group, pre_comp->precomp[0], ctx)) { + EC_POINT_free(pre_comp_generator); goto err; + } if (0 == EC_POINT_cmp(group, generator, pre_comp_generator, ctx)) preComputedTable = (const PRECOMP256_ROW *)pre_comp->precomp; @@ -1255,20 +1291,16 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, * Without a precomputed table for the generator, it has to be * handled like a normal point. */ - const BIGNUM **new_scalars; - const EC_POINT **new_points; - new_scalars = OPENSSL_malloc((num + 1) * sizeof(BIGNUM *)); if (!new_scalars) { ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE); - return 0; + goto err; } new_points = OPENSSL_malloc((num + 1) * sizeof(EC_POINT *)); if (!new_points) { - OPENSSL_free(new_scalars); ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE); - return 0; + goto err; } memcpy(new_scalars, scalars, num * sizeof(BIGNUM *)); @@ -1286,27 +1318,31 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, if (p_is_infinity) out = &p.p; - ecp_nistz256_windowed_mul(group, out, scalars, points, num, ctx); + if (!ecp_nistz256_windowed_mul(group, out, scalars, points, num, ctx)) + goto err; if (!p_is_infinity) ecp_nistz256_point_add(&p.p, &p.p, out); } - if (no_precomp_for_generator) { - OPENSSL_free(points); - OPENSSL_free(scalars); + /* Not constant-time, but we're only operating on the public output. */ + if (!ecp_nistz256_set_words(&r->X, p.p.X) || + !ecp_nistz256_set_words(&r->Y, p.p.Y) || + !ecp_nistz256_set_words(&r->Z, p.p.Z)) { + goto err; } - - memcpy(r->X.d, p.p.X, sizeof(p.p.X)); - memcpy(r->Y.d, p.p.Y, sizeof(p.p.Y)); - memcpy(r->Z.d, p.p.Z, sizeof(p.p.Z)); - bn_correct_top(&r->X); - bn_correct_top(&r->Y); - bn_correct_top(&r->Z); + r->Z_is_one = is_one(p.p.Z) & 1; ret = 1; - err: +err: + if (ctx) + BN_CTX_end(ctx); + BN_CTX_free(new_ctx); + if (new_points) + OPENSSL_free(new_points); + if (new_scalars) + OPENSSL_free(new_scalars); return ret; } @@ -1319,6 +1355,7 @@ static int ecp_nistz256_get_affine(const EC_GROUP *group, BN_ULONG x_aff[P256_LIMBS]; BN_ULONG y_aff[P256_LIMBS]; BN_ULONG point_x[P256_LIMBS], point_y[P256_LIMBS], point_z[P256_LIMBS]; + BN_ULONG x_ret[P256_LIMBS], y_ret[P256_LIMBS]; if (EC_POINT_is_at_infinity(group, point)) { ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_POINT_AT_INFINITY); @@ -1337,19 +1374,17 @@ static int ecp_nistz256_get_affine(const EC_GROUP *group, ecp_nistz256_mul_mont(x_aff, z_inv2, point_x); if (x != NULL) { - bn_wexpand(x, P256_LIMBS); - x->top = P256_LIMBS; - ecp_nistz256_from_mont(x->d, x_aff); - bn_correct_top(x); + ecp_nistz256_from_mont(x_ret, x_aff); + if (!ecp_nistz256_set_words(x, x_ret)) + return 0; } if (y != NULL) { ecp_nistz256_mul_mont(z_inv3, z_inv3, z_inv2); ecp_nistz256_mul_mont(y_aff, z_inv3, point_y); - bn_wexpand(y, P256_LIMBS); - y->top = P256_LIMBS; - ecp_nistz256_from_mont(y->d, y_aff); - bn_correct_top(y); + ecp_nistz256_from_mont(y_ret, y_aff); + if (!ecp_nistz256_set_words(y, y_ret)) + return 0; } return 1; |