Changes between 1.1.1 and 3.0.0 [xx XXX xxxx]
+ *) Added SCA hardening for modular field inversion in EC_GROUP through
+ a new dedicated field_inv() pointer in EC_METHOD.
+ This also addresses a leakage affecting conversions from projective
+ to affine coordinates.
+ [Billy Bob Brumley, Nicola Tuveri]
+
*) Added EVP_KDF, an EVP layer KDF API, to simplify adding KDF and PRF
implementations. This includes an EVP_PKEY to EVP_KDF bridge for
those algorithms that were already supported through the EVP_PKEY API
|| !group->meth->field_mul(group, t2, t2, t0, ctx)
|| !BN_GF2m_add(t1, t2, t1)
|| !group->meth->field_mul(group, t2, p->X, t0, ctx)
- || !BN_GF2m_mod_inv(t2, t2, group->field, ctx)
+ || !group->meth->field_inv(group, t2, t2, ctx)
|| !group->meth->field_mul(group, t1, t1, t2, ctx)
|| !group->meth->field_mul(group, r->X, r->Z, t2, ctx)
|| !BN_GF2m_add(t2, p->X, r->X)
return ret;
}
+/*-
+ * Computes the multiplicative inverse of a in GF(2^m), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * SCA hardening is with blinding: BN_GF2m_mod_inv does that.
+ */
+static int ec_GF2m_simple_field_inv(const EC_GROUP *group, BIGNUM *r,
+ const BIGNUM *a, BN_CTX *ctx)
+{
+ int ret;
+
+ if (!(ret = BN_GF2m_mod_inv(r, a, group->field, ctx)))
+ ECerr(EC_F_EC_GF2M_SIMPLE_FIELD_INV, EC_R_CANNOT_INVERT);
+ return ret;
+}
+
const EC_METHOD *EC_GF2m_simple_method(void)
{
static const EC_METHOD ret = {
ec_GF2m_simple_field_mul,
ec_GF2m_simple_field_sqr,
ec_GF2m_simple_field_div,
+ ec_GF2m_simple_field_inv,
0, /* field_encode */
0, /* field_decode */
0, /* field_set_to_one */
/*
* Generated by util/mkerr.pl DO NOT EDIT
- * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
"ec_asn1_group2fieldid"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GF2M_MONTGOMERY_POINT_MULTIPLY, 0),
"ec_GF2m_montgomery_point_multiply"},
+ {ERR_PACK(ERR_LIB_EC, EC_F_EC_GF2M_SIMPLE_FIELD_INV, 0),
+ "ec_GF2m_simple_field_inv"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT, 0),
"ec_GF2m_simple_group_check_discriminant"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE, 0),
"ec_GFp_mont_field_decode"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_MONT_FIELD_ENCODE, 0),
"ec_GFp_mont_field_encode"},
+ {ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_MONT_FIELD_INV, 0),
+ "ec_GFp_mont_field_inv"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_MONT_FIELD_MUL, 0),
"ec_GFp_mont_field_mul"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE, 0),
"ec_GFp_nist_group_set_curve"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES, 0),
"ec_GFp_simple_blind_coordinates"},
+ {ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_SIMPLE_FIELD_INV, 0),
+ "ec_GFp_simple_field_inv"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT, 0),
"ec_GFp_simple_group_check_discriminant"},
{ERR_PACK(ERR_LIB_EC, EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE, 0),
{ERR_PACK(ERR_LIB_EC, 0, EC_R_BAD_SIGNATURE), "bad signature"},
{ERR_PACK(ERR_LIB_EC, 0, EC_R_BIGNUM_OUT_OF_RANGE), "bignum out of range"},
{ERR_PACK(ERR_LIB_EC, 0, EC_R_BUFFER_TOO_SMALL), "buffer too small"},
+ {ERR_PACK(ERR_LIB_EC, 0, EC_R_CANNOT_INVERT), "cannot invert"},
{ERR_PACK(ERR_LIB_EC, 0, EC_R_COORDINATES_OUT_OF_RANGE),
"coordinates out of range"},
{ERR_PACK(ERR_LIB_EC, 0, EC_R_CURVE_DOES_NOT_SUPPORT_ECDH),
int (*field_sqr) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
int (*field_div) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
+ /*-
+ * 'field_inv' computes the multipicative inverse of a in the field,
+ * storing the result in r.
+ *
+ * If 'a' is zero (or equivalent), you'll get an EC_R_CANNOT_INVERT error.
+ */
+ int (*field_inv) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
/* e.g. to Montgomery */
int (*field_encode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
const BIGNUM *b, BN_CTX *);
int ec_GFp_simple_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
+int ec_GFp_simple_field_inv(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *);
int ec_GFp_simple_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
BN_CTX *ctx);
int ec_GFp_simple_ladder_pre(const EC_GROUP *group,
const BIGNUM *b, BN_CTX *);
int ec_GFp_mont_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
+int ec_GFp_mont_field_inv(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *);
int ec_GFp_mont_field_encode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int ec_GFp_mont_field_decode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
ec_GFp_mont_field_mul,
ec_GFp_mont_field_sqr,
0 /* field_div */ ,
+ ec_GFp_mont_field_inv,
ec_GFp_mont_field_encode,
ec_GFp_mont_field_decode,
ec_GFp_mont_field_set_to_one,
return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
}
+/*-
+ * Computes the multiplicative inverse of a in GF(p), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * We have a Mont structure, so SCA hardening is FLT inversion.
+ */
+int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *ctx)
+{
+ BIGNUM *e = NULL;
+ BN_CTX *new_ctx = NULL;
+ int ret = 0;
+
+ if (group->field_data1 == NULL)
+ return 0;
+
+ if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
+ return 0;
+
+ BN_CTX_start(ctx);
+ if ((e = BN_CTX_get(ctx)) == NULL)
+ goto err;
+
+ /* Inverse in constant time with Fermats Little Theorem */
+ if (!BN_set_word(e, 2))
+ goto err;
+ if (!BN_sub(e, group->field, e))
+ goto err;
+ /*-
+ * Exponent e is public.
+ * No need for scatter-gather or BN_FLG_CONSTTIME.
+ */
+ if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
+ goto err;
+
+ /* throw an error on zero */
+ if (BN_is_zero(r)) {
+ ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
+ goto err;
+ }
+
+ ret = 1;
+
+ err:
+ BN_CTX_end(ctx);
+ BN_CTX_free(new_ctx);
+ return ret;
+}
+
int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
const BIGNUM *a, BN_CTX *ctx)
{
ec_GFp_nist_field_mul,
ec_GFp_nist_field_sqr,
0 /* field_div */ ,
+ ec_GFp_simple_field_inv,
0 /* field_encode */ ,
0 /* field_decode */ ,
0, /* field_set_to_one */
ec_GFp_nist_field_mul,
ec_GFp_nist_field_sqr,
0 /* field_div */ ,
+ ec_GFp_simple_field_inv,
0 /* field_encode */ ,
0 /* field_decode */ ,
0, /* field_set_to_one */
ec_GFp_nist_field_mul,
ec_GFp_nist_field_sqr,
0 /* field_div */ ,
+ ec_GFp_simple_field_inv,
0 /* field_encode */ ,
0 /* field_decode */ ,
0, /* field_set_to_one */
ec_GFp_nist_field_mul,
ec_GFp_nist_field_sqr,
0 /* field_div */ ,
+ ec_GFp_simple_field_inv,
0 /* field_encode */ ,
0 /* field_decode */ ,
0, /* field_set_to_one */
ec_GFp_mont_field_mul,
ec_GFp_mont_field_sqr,
0, /* field_div */
+ ec_GFp_mont_field_inv,
ec_GFp_mont_field_encode,
ec_GFp_mont_field_decode,
ec_GFp_mont_field_set_to_one,
ec_GFp_simple_field_mul,
ec_GFp_simple_field_sqr,
0 /* field_div */ ,
+ ec_GFp_simple_field_inv,
0 /* field_encode */ ,
0 /* field_decode */ ,
0, /* field_set_to_one */
}
}
} else {
- if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) {
+ if (!group->meth->field_inv(group, Z_1, Z_, ctx)) {
ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES,
ERR_R_BN_LIB);
goto err;
* points[i]->Z by its inverse.
*/
- if (!BN_mod_inverse(tmp, prod_Z[num - 1], group->field, ctx)) {
+ if (!group->meth->field_inv(group, tmp, prod_Z[num - 1], ctx)) {
ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB);
goto err;
}
return BN_mod_sqr(r, a, group->field, ctx);
}
+/*-
+ * Computes the multiplicative inverse of a in GF(p), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * Since we don't have a Mont structure here, SCA hardening is with blinding.
+ */
+int ec_GFp_simple_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *ctx)
+{
+ BIGNUM *e = NULL;
+ BN_CTX *new_ctx = NULL;
+ int ret = 0;
+
+ if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
+ return 0;
+
+ BN_CTX_start(ctx);
+ if ((e = BN_CTX_get(ctx)) == NULL)
+ goto err;
+
+ do {
+ if (!BN_priv_rand_range(e, group->field))
+ goto err;
+ } while (BN_is_zero(e));
+
+ /* r := a * e */
+ if (!group->meth->field_mul(group, r, a, e, ctx))
+ goto err;
+ /* r := 1/(a * e) */
+ if (!BN_mod_inverse(r, r, group->field, ctx)) {
+ ECerr(EC_F_EC_GFP_SIMPLE_FIELD_INV, EC_R_CANNOT_INVERT);
+ goto err;
+ }
+ /* r := e/(a * e) = 1/a */
+ if (!group->meth->field_mul(group, r, r, e, ctx))
+ goto err;
+
+ ret = 1;
+
+ err:
+ BN_CTX_end(ctx);
+ BN_CTX_free(new_ctx);
+ return ret;
+}
+
/*-
* Apply randomization of EC point projective coordinates:
*
EC_F_EC_ASN1_GROUP2CURVE:153:ec_asn1_group2curve
EC_F_EC_ASN1_GROUP2FIELDID:154:ec_asn1_group2fieldid
EC_F_EC_GF2M_MONTGOMERY_POINT_MULTIPLY:208:ec_GF2m_montgomery_point_multiply
+EC_F_EC_GF2M_SIMPLE_FIELD_INV:296:ec_GF2m_simple_field_inv
EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT:159:\
ec_GF2m_simple_group_check_discriminant
EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE:195:ec_GF2m_simple_group_set_curve
ec_GF2m_simple_set_compressed_coordinates
EC_F_EC_GFP_MONT_FIELD_DECODE:133:ec_GFp_mont_field_decode
EC_F_EC_GFP_MONT_FIELD_ENCODE:134:ec_GFp_mont_field_encode
+EC_F_EC_GFP_MONT_FIELD_INV:297:ec_GFp_mont_field_inv
EC_F_EC_GFP_MONT_FIELD_MUL:131:ec_GFp_mont_field_mul
EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE:209:ec_GFp_mont_field_set_to_one
EC_F_EC_GFP_MONT_FIELD_SQR:132:ec_GFp_mont_field_sqr
EC_F_EC_GFP_NIST_FIELD_SQR:201:ec_GFp_nist_field_sqr
EC_F_EC_GFP_NIST_GROUP_SET_CURVE:202:ec_GFp_nist_group_set_curve
EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES:287:ec_GFp_simple_blind_coordinates
+EC_F_EC_GFP_SIMPLE_FIELD_INV:298:ec_GFp_simple_field_inv
EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT:165:\
ec_GFp_simple_group_check_discriminant
EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE:166:ec_GFp_simple_group_set_curve
EC_R_BAD_SIGNATURE:156:bad signature
EC_R_BIGNUM_OUT_OF_RANGE:144:bignum out of range
EC_R_BUFFER_TOO_SMALL:100:buffer too small
+EC_R_CANNOT_INVERT:165:cannot invert
EC_R_COORDINATES_OUT_OF_RANGE:146:coordinates out of range
EC_R_CURVE_DOES_NOT_SUPPORT_ECDH:160:curve does not support ecdh
EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING:159:curve does not support signing
/*
* Generated by util/mkerr.pl DO NOT EDIT
- * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
# define EC_F_EC_ASN1_GROUP2CURVE 153
# define EC_F_EC_ASN1_GROUP2FIELDID 154
# define EC_F_EC_GF2M_MONTGOMERY_POINT_MULTIPLY 208
+# define EC_F_EC_GF2M_SIMPLE_FIELD_INV 296
# define EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT 159
# define EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE 195
# define EC_F_EC_GF2M_SIMPLE_LADDER_POST 285
# define EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES 164
# define EC_F_EC_GFP_MONT_FIELD_DECODE 133
# define EC_F_EC_GFP_MONT_FIELD_ENCODE 134
+# define EC_F_EC_GFP_MONT_FIELD_INV 297
# define EC_F_EC_GFP_MONT_FIELD_MUL 131
# define EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE 209
# define EC_F_EC_GFP_MONT_FIELD_SQR 132
# define EC_F_EC_GFP_NIST_FIELD_SQR 201
# define EC_F_EC_GFP_NIST_GROUP_SET_CURVE 202
# define EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES 287
+# define EC_F_EC_GFP_SIMPLE_FIELD_INV 298
# define EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT 165
# define EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE 166
# define EC_F_EC_GFP_SIMPLE_MAKE_AFFINE 102
# define EC_R_BAD_SIGNATURE 156
# define EC_R_BIGNUM_OUT_OF_RANGE 144
# define EC_R_BUFFER_TOO_SMALL 100
+# define EC_R_CANNOT_INVERT 165
# define EC_R_COORDINATES_OUT_OF_RANGE 146
# define EC_R_CURVE_DOES_NOT_SUPPORT_ECDH 160
# define EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING 159