Simplify and fix ec_GFp_simple_points_make_affine (0fe73d6c) · Commits · CYBER - Cyber Security / TS 103 523 MSP / ETS / ETS OpenSSL

CHANGES

+5 −0

Original line number	Diff line number	Diff line
		@@ -310,6 +310,11 @@

		Changes between 1.0.1e and 1.0.2 [xx XXX xxxx]

		*) Fix ec_GFp_simple_points_make_affine (thus, EC_POINTs_mul etc.)
		for corner cases. (Certain input points at infinity could lead to
		bogus results, with non-infinity inputs mapped to infinity too.)
		[Bodo Moeller]

		*) Initial support for PowerISA 2.0.7, first implemented in POWER8.
		This covers AES, SHA256/512 and GHASH. "Initial" means that most
		common cases are optimized and there still is room for further

crypto/ec/ecp_smpl.c

+76 −98

Original line number	Diff line number	Diff line
		@@ -1175,9 +1175,8 @@ int ec_GFp_simple_make_affine(const EC_GROUP group, EC_POINT point, BN_CTX *ct
		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;
		BIGNUM tmp, tmp_Z;
		BIGNUM **prod_Z = NULL;
		size_t i;
		int ret = 0;

		@@ -1192,110 +1191,90 @@ int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT
		}

		BN_CTX_start(ctx);
		tmp0 = BN_CTX_get(ctx);
		tmp1 = BN_CTX_get(ctx);
		if (tmp0 == NULL \|\| tmp1 == 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 = OPENSSL_malloc(pow2 * sizeof heap[0]);
		if (heap == NULL) goto err;
		tmp = BN_CTX_get(ctx);
		tmp_Z = BN_CTX_get(ctx);
		if (tmp == NULL \|\| tmp_Z == 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;
		prod_Z = OPENSSL_malloc(num * sizeof prod_Z[0]);
		if (prod_Z == NULL) goto err;
		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;
		prod_Z[i] = BN_new();
		if (prod_Z[i] == NULL) goto err;
		}

		if (heap[2*i] != NULL)
		{
		if ((heap[2i + 1] == NULL) \|\| BN_is_zero(heap[2i + 1]))
		/* Set each prod_Z[i] to the product of points[0]->Z .. points[i]->Z,
		* skipping any zero-valued inputs (pretend that they're 1). */

		if (!BN_is_zero(&points[0]->Z))
		{
		if (!BN_copy(heap[i], heap[2*i])) goto err;
		if (!BN_copy(prod_Z[0], &points[0]->Z)) goto err;
		}
		else
		{
		if (BN_is_zero(heap[2*i]))
		if (group->meth->field_set_to_one != 0)
		{
		if (!BN_copy(heap[i], heap[2*i + 1])) goto err;
		if (!group->meth->field_set_to_one(group, prod_Z[0], ctx)) goto err;
		}
		else
		{
		if (!group->meth->field_mul(group, heap[i],
		heap[2i], heap[2i + 1], ctx)) goto err;
		if (!BN_one(prod_Z[0])) goto err;
		}
		}

		for (i = 1; i < num; i++)
		{
		if (!BN_is_zero(&points[i]->Z))
		{
		if (!group->meth->field_mul(group, prod_Z[i], prod_Z[i - 1], &points[i]->Z, ctx)) goto err;
		}
		else
		{
		if (!BN_copy(prod_Z[i], prod_Z[i - 1])) goto err;
		}
		}

		/* invert heap[1] */
		if (!BN_is_zero(heap[1]))
		{
		if (!BN_mod_inverse(heap[1], heap[1], &group->field, ctx))
		/* Now use a single explicit inversion to replace every
		* non-zero points[i]->Z by its inverse. */

		if (!BN_mod_inverse(tmp, prod_Z[num - 1], &group->field, ctx))
		{
		ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB);
		goto err;
		}
		}
		if (group->meth->field_encode != 0)
		{
		/* in the Montgomery case, we just turned R*H (representing H)
		/* In the Montgomery case, we just turned R*H (representing H)
		* into 1/(RH), 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;
		* i.e. we need to multiply by the Montgomery factor twice. */
		if (!group->meth->field_encode(group, tmp, tmp, ctx)) goto err;
		if (!group->meth->field_encode(group, tmp, tmp, ctx)) goto err;
		}

		/* set other heap[i]'s to their inverses */
		for (i = 2; i < pow2/2 + num; i += 2)
		for (i = num - 1; i > 0; --i)
		{
		/* i is even */
		if ((heap[i + 1] != NULL) && !BN_is_zero(heap[i + 1]))
		/* Loop invariant: tmp is the product of the inverses of
		* points[0]->Z .. points[i]->Z (zero-valued inputs skipped). */
		if (!BN_is_zero(&points[i]->Z))
		{
		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;
		/* Set tmp_Z to the inverse of points[i]->Z (as product
		* of Z inverses 0 .. i, Z values 0 .. i - 1). */
		if (!group->meth->field_mul(group, tmp_Z, prod_Z[i - 1], tmp, ctx)) goto err;
		/* Update tmp to satisfy the loop invariant for i - 1. */
		if (!group->meth->field_mul(group, tmp, tmp, &points[i]->Z, ctx)) goto err;
		/* Replace points[i]->Z by its inverse. */
		if (!BN_copy(&points[i]->Z, tmp_Z)) goto err;
		}
		else
		{
		if (!BN_copy(heap[i], heap[i/2])) goto err;
		}

		if (!BN_is_zero(&points[0]->Z))
		{
		/* Replace points[0]->Z by its inverse. */
		if (!BN_copy(&points[0]->Z, tmp)) goto err;
		}

		/* we have replaced all non-zero Z's by their inverses, now fix up all the points */
		/* Finally, fix up the X and Y coordinates for all points. */

		for (i = 0; i < num; i++)
		{
		EC_POINT *p = points[i];
		@@ -1304,11 +1283,11 @@ int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT
		{
		/* 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_sqr(group, tmp, &p->Z, ctx)) goto err;
		if (!group->meth->field_mul(group, &p->X, &p->X, tmp, 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_mul(group, tmp, tmp, &p->Z, ctx)) goto err;
		if (!group->meth->field_mul(group, &p->Y, &p->Y, tmp, ctx)) goto err;

		if (group->meth->field_set_to_one != 0)
		{
		@@ -1328,15 +1307,14 @@ int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num, EC_POINT
		BN_CTX_end(ctx);
		if (new_ctx != NULL)
		BN_CTX_free(new_ctx);
		if (heap != NULL)
		if (prod_Z != NULL)
		{
		/* heap[pow2/2] .. heap[pow2-1] have not been allocated locally! */
		for (i = pow2/2 - 1; i > 0; i--)
		for (i = 0; i < num; i++)
		{
		if (heap[i] != NULL)
		BN_clear_free(heap[i]);
		if (prod_Z[i] != NULL)
		BN_clear_free(prod_Z[i]);
		}
		OPENSSL_free(heap);
		OPENSSL_free(prod_Z);
		}
		return ret;
		}

crypto/ec/ectest.c

+49 −14

Original line number	Diff line number	Diff line
		@@ -199,6 +199,7 @@ static void group_order_tests(EC_GROUP *group)
		EC_POINT *P = EC_POINT_new(group);
		EC_POINT *Q = EC_POINT_new(group);
		BN_CTX *ctx = BN_CTX_new();
		int i;

		n1 = BN_new(); n2 = BN_new(); order = BN_new();
		fprintf(stdout, "verify group order ...");
		@@ -212,21 +213,55 @@ static void group_order_tests(EC_GROUP *group)
		if (!EC_POINT_mul(group, Q, order, NULL, NULL, ctx)) ABORT;
		if (!EC_POINT_is_at_infinity(group, Q)) ABORT;
		fprintf(stdout, " ok\n");
		fprintf(stdout, "long/negative scalar tests ... ");
		fprintf(stdout, "long/negative scalar tests ");
		for (i = 1; i <= 2; i++)
		{
		const BIGNUM *scalars[6];
		const EC_POINT *points[6];

		fprintf(stdout, i == 1 ?
		"allowing precomputation ... " :
		"without precomputation ... ");
		if (!BN_set_word(n1, i)) ABORT;
		/* If i == 1, P will be the predefined generator for which
		* EC_GROUP_precompute_mult has set up precomputation. */
		if (!EC_POINT_mul(group, P, n1, NULL, NULL, ctx)) ABORT;

		if (!BN_one(n1)) ABORT;
		/* n1 = 1 - order */
		if (!BN_sub(n1, n1, order)) ABORT;
		if (!EC_POINT_mul(group, Q, NULL, P, n1, ctx)) ABORT;
		if (0 != EC_POINT_cmp(group, Q, P, ctx)) ABORT;

		/* n2 = 1 + order */
		if (!BN_add(n2, order, BN_value_one())) ABORT;
		if (!EC_POINT_mul(group, Q, NULL, P, n2, ctx)) ABORT;
		if (0 != EC_POINT_cmp(group, Q, P, ctx)) ABORT;
		/* n2 = (1 - order) * (1 + order) */

		/* n2 = (1 - order) * (1 + order) = 1 - order^2 */
		if (!BN_mul(n2, n1, n2, ctx)) ABORT;
		if (!EC_POINT_mul(group, Q, NULL, P, n2, ctx)) ABORT;
		if (0 != EC_POINT_cmp(group, Q, P, ctx)) ABORT;

		/* n2 = order^2 - 1 */
		BN_set_negative(n2, 0);
		if (!EC_POINT_mul(group, Q, NULL, P, n2, ctx)) ABORT;
		/* Add P to verify the result. */
		if (!EC_POINT_add(group, Q, Q, P, ctx)) ABORT;
		if (!EC_POINT_is_at_infinity(group, Q)) ABORT;

		/* Exercise EC_POINTs_mul, including corner cases. */
		scalars[0] = n1; points[0] = Q; /* => infinity */
		scalars[1] = n2; points[1] = P; /* => -P */
		scalars[2] = n1; points[2] = Q; /* => infinity */
		scalars[3] = n2; points[3] = Q; /* => infinity */
		scalars[4] = n1; points[4] = P; /* => P */
		scalars[5] = n2; points[5] = Q; /* => infinity */
		if (!EC_POINTs_mul(group, Q, NULL, 5, points, scalars, ctx)) ABORT;
		if (!EC_POINT_is_at_infinity(group, Q)) ABORT;
		}
		fprintf(stdout, "ok\n");

		EC_POINT_free(P);
		EC_POINT_free(Q);
		BN_free(n1);