Small Issues & Maintenance

-=-=-=-=-=-=-=-=-=-=-=-=-=

-Begin work on Navigation Meshes (simple pathfinding for now, will improve soon)
-More doc on theme overriding
-Upgraded OpenSSL to version without bugs
-Misc bugfixes

1 files changed, 197 insertions, 0 deletions

diff --git a/drivers/builtin_openssl2/crypto/ec/ecp_nistputil.c b/drivers/builtin_openssl2/crypto/ec/ecp_nistputil.c
new file mode 100644
index 0000000000..c8140c807f
--- /dev/null
+++ b/drivers/builtin_openssl2/crypto/ec/ecp_nistputil.c
@@ -0,0 +1,197 @@
+/* crypto/ec/ecp_nistputil.c */
+/*
+ * Written by Bodo Moeller for the OpenSSL project.
+ */
+/* Copyright 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ *
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include <openssl/opensslconf.h>
+#ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
+
+/*
+ * Common utility functions for ecp_nistp224.c, ecp_nistp256.c, ecp_nistp521.c.
+ */
+
+#include <stddef.h>
+#include "ec_lcl.h"
+
+/* Convert an array of points into affine coordinates.
+ * (If the point at infinity is found (Z = 0), it remains unchanged.)
+ * This function is essentially an equivalent to EC_POINTs_make_affine(), but
+ * works with the internal representation of points as used by ecp_nistp###.c
+ * rather than with (BIGNUM-based) EC_POINT data structures.
+ *
+ * point_array is the input/output buffer ('num' points in projective form,
+ * i.e. three coordinates each), based on an internal representation of
+ * field elements of size 'felem_size'.
+ *
+ * tmp_felems needs to point to a temporary array of 'num'+1 field elements
+ * for storage of intermediate values.
+ */
+void ec_GFp_nistp_points_make_affine_internal(size_t num, void *point_array,
+	size_t felem_size, void *tmp_felems,
+	void (*felem_one)(void *out),
+	int (*felem_is_zero)(const void *in),
+	void (*felem_assign)(void *out, const void *in),
+	void (*felem_square)(void *out, const void *in),
+	void (*felem_mul)(void *out, const void *in1, const void *in2),
+	void (*felem_inv)(void *out, const void *in),
+	void (*felem_contract)(void *out, const void *in))
+	{
+	int i = 0;
+
+#define tmp_felem(I) (&((char *)tmp_felems)[(I) * felem_size])
+#define X(I) (&((char *)point_array)[3*(I) * felem_size])
+#define Y(I) (&((char *)point_array)[(3*(I) + 1) * felem_size])
+#define Z(I) (&((char *)point_array)[(3*(I) + 2) * felem_size])
+
+	if (!felem_is_zero(Z(0)))
+		felem_assign(tmp_felem(0), Z(0));
+	else
+		felem_one(tmp_felem(0));
+	for (i = 1; i < (int)num; i++)
+		{
+		if (!felem_is_zero(Z(i)))
+			felem_mul(tmp_felem(i), tmp_felem(i-1), Z(i));
+		else
+			felem_assign(tmp_felem(i), tmp_felem(i-1));
+		}
+	/* Now each tmp_felem(i) is the product of Z(0) .. Z(i), skipping any zero-valued factors:
+	 * if Z(i) = 0, we essentially pretend that Z(i) = 1 */
+
+	felem_inv(tmp_felem(num-1), tmp_felem(num-1));
+	for (i = num - 1; i >= 0; i--)
+		{
+		if (i > 0)
+			/* tmp_felem(i-1) is the product of Z(0) .. Z(i-1),
+			 * tmp_felem(i) is the inverse of the product of Z(0) .. Z(i)
+			 */
+			felem_mul(tmp_felem(num), tmp_felem(i-1), tmp_felem(i)); /* 1/Z(i) */
+		else
+			felem_assign(tmp_felem(num), tmp_felem(0)); /* 1/Z(0) */
+
+		if (!felem_is_zero(Z(i)))
+			{
+			if (i > 0)
+				/* For next iteration, replace tmp_felem(i-1) by its inverse */
+				felem_mul(tmp_felem(i-1), tmp_felem(i), Z(i));
+
+			/* Convert point (X, Y, Z) into affine form (X/(Z^2), Y/(Z^3), 1) */
+			felem_square(Z(i), tmp_felem(num)); /* 1/(Z^2) */
+			felem_mul(X(i), X(i), Z(i)); /* X/(Z^2) */
+			felem_mul(Z(i), Z(i), tmp_felem(num)); /* 1/(Z^3) */
+			felem_mul(Y(i), Y(i), Z(i)); /* Y/(Z^3) */
+			felem_contract(X(i), X(i));
+			felem_contract(Y(i), Y(i));
+			felem_one(Z(i));
+			}
+		else
+			{
+			if (i > 0)
+				/* For next iteration, replace tmp_felem(i-1) by its inverse */
+				felem_assign(tmp_felem(i-1), tmp_felem(i));
+			}
+		}
+	}
+
+/*
+ * This function looks at 5+1 scalar bits (5 current, 1 adjacent less
+ * significant bit), and recodes them into a signed digit for use in fast point
+ * multiplication: the use of signed rather than unsigned digits means that
+ * fewer points need to be precomputed, given that point inversion is easy
+ * (a precomputed point dP makes -dP available as well).
+ *
+ * BACKGROUND:
+ *
+ * Signed digits for multiplication were introduced by Booth ("A signed binary
+ * multiplication technique", Quart. Journ. Mech. and Applied Math., vol. IV,
+ * pt. 2 (1951), pp. 236-240), in that case for multiplication of integers.
+ * Booth's original encoding did not generally improve the density of nonzero
+ * digits over the binary representation, and was merely meant to simplify the
+ * handling of signed factors given in two's complement; but it has since been
+ * shown to be the basis of various signed-digit representations that do have
+ * further advantages, including the wNAF, using the following general approach:
+ *
+ * (1) Given a binary representation
+ *
+ *       b_k  ...  b_2  b_1  b_0,
+ *
+ *     of a nonnegative integer (b_k in {0, 1}), rewrite it in digits 0, 1, -1
+ *     by using bit-wise subtraction as follows:
+ *
+ *        b_k b_(k-1)  ...  b_2  b_1  b_0
+ *      -     b_k      ...  b_3  b_2  b_1  b_0
+ *       -------------------------------------
+ *        s_k b_(k-1)  ...  s_3  s_2  s_1  s_0
+ *
+ *     A left-shift followed by subtraction of the original value yields a new
+ *     representation of the same value, using signed bits s_i = b_(i+1) - b_i.
+ *     This representation from Booth's paper has since appeared in the
+ *     literature under a variety of different names including "reversed binary
+ *     form", "alternating greedy expansion", "mutual opposite form", and
+ *     "sign-alternating {+-1}-representation".
+ *
+ *     An interesting property is that among the nonzero bits, values 1 and -1
+ *     strictly alternate.
+ *
+ * (2) Various window schemes can be applied to the Booth representation of
+ *     integers: for example, right-to-left sliding windows yield the wNAF
+ *     (a signed-digit encoding independently discovered by various researchers
+ *     in the 1990s), and left-to-right sliding windows yield a left-to-right
+ *     equivalent of the wNAF (independently discovered by various researchers
+ *     around 2004).
+ *
+ * To prevent leaking information through side channels in point multiplication,
+ * we need to recode the given integer into a regular pattern: sliding windows
+ * as in wNAFs won't do, we need their fixed-window equivalent -- which is a few
+ * decades older: we'll be using the so-called "modified Booth encoding" due to
+ * MacSorley ("High-speed arithmetic in binary computers", Proc. IRE, vol. 49
+ * (1961), pp. 67-91), in a radix-2^5 setting.  That is, we always combine five
+ * signed bits into a signed digit:
+ *
+ *       s_(4j + 4) s_(4j + 3) s_(4j + 2) s_(4j + 1) s_(4j)
+ *
+ * The sign-alternating property implies that the resulting digit values are
+ * integers from -16 to 16.
+ *
+ * Of course, we don't actually need to compute the signed digits s_i as an
+ * intermediate step (that's just a nice way to see how this scheme relates
+ * to the wNAF): a direct computation obtains the recoded digit from the
+ * six bits b_(4j + 4) ... b_(4j - 1).
+ *
+ * This function takes those five bits as an integer (0 .. 63), writing the
+ * recoded digit to *sign (0 for positive, 1 for negative) and *digit (absolute
+ * value, in the range 0 .. 8).  Note that this integer essentially provides the
+ * input bits "shifted to the left" by one position: for example, the input to
+ * compute the least significant recoded digit, given that there's no bit b_-1,
+ * has to be b_4 b_3 b_2 b_1 b_0 0.
+ *
+ */
+void ec_GFp_nistp_recode_scalar_bits(unsigned char *sign, unsigned char *digit, unsigned char in)
+	{
+	unsigned char s, d;
+
+	s = ~((in >> 5) - 1); /* sets all bits to MSB(in), 'in' seen as 6-bit value */
+	d = (1 << 6) - in - 1;
+	d = (d & s) | (in & ~s);
+	d = (d >> 1) + (d & 1);
+
+	*sign = s & 1;
+	*digit = d;
+	}
+#else
+static void *dummy=&dummy;
+#endif