mirror of https://github.com/skeeto/enchive.git
Working stuff.
Christopher Wellons
parent
c93cbc96cf
commit
8c5f0c9d21
3
Makefile
3
Makefile
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@ -3,12 +3,13 @@
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CC = cc
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CFLAGS = -ansi -pedantic -Wall -Wextra -O3 -g3
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objects = enchive.o chacha.o
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objects = enchive.o chacha.o curve25519-donna.o
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enchive: $(objects)
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$(CC) $(LDFLAGS) -o $@ $(objects) $(LDLIBS)
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enchive.o: enchive.c
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chacha.o: chacha.c
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curve25519-donna.o: curve25519-donna.c
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clean:
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rm -f enchive $(objects)
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@ -0,0 +1,853 @@
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/* Copyright 2008, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* curve25519-donna: Curve25519 elliptic curve, public key function
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*
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* http://code.google.com/p/curve25519-donna/
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*
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* Adam Langley <agl@imperialviolet.org>
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*
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* Derived from public domain C code by Daniel J. Bernstein <djb@cr.yp.to>
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*
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* More information about curve25519 can be found here
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* http://cr.yp.to/ecdh.html
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*
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* djb's sample implementation of curve25519 is written in a special assembly
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* language called qhasm and uses the floating point registers.
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*
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* This is, almost, a clean room reimplementation from the curve25519 paper. It
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* uses many of the tricks described therein. Only the crecip function is taken
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* from the sample implementation. */
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#include <string.h>
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#include <stdint.h>
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typedef uint8_t u8;
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typedef int32_t s32;
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typedef int64_t limb;
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/* Field element representation:
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*
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* Field elements are written as an array of signed, 64-bit limbs, least
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* significant first. The value of the field element is:
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* x[0] + 2^26·x[1] + x^51·x[2] + 2^102·x[3] + ...
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*
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* i.e. the limbs are 26, 25, 26, 25, ... bits wide. */
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/* Sum two numbers: output += in */
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static void fsum(limb *output, const limb *in) {
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unsigned i;
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for (i = 0; i < 10; i += 2) {
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output[0+i] = output[0+i] + in[0+i];
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output[1+i] = output[1+i] + in[1+i];
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}
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}
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/* Find the difference of two numbers: output = in - output
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* (note the order of the arguments!). */
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static void fdifference(limb *output, const limb *in) {
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unsigned i;
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for (i = 0; i < 10; ++i) {
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output[i] = in[i] - output[i];
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}
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}
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/* Multiply a number by a scalar: output = in * scalar */
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static void fscalar_product(limb *output, const limb *in, const limb scalar) {
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unsigned i;
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for (i = 0; i < 10; ++i) {
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output[i] = in[i] * scalar;
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}
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}
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/* Multiply two numbers: output = in2 * in
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*
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* output must be distinct to both inputs. The inputs are reduced coefficient
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* form, the output is not.
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*
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* output[x] <= 14 * the largest product of the input limbs. */
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static void fproduct(limb *output, const limb *in2, const limb *in) {
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output[0] = ((limb) ((s32) in2[0])) * ((s32) in[0]);
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output[1] = ((limb) ((s32) in2[0])) * ((s32) in[1]) +
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((limb) ((s32) in2[1])) * ((s32) in[0]);
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output[2] = 2 * ((limb) ((s32) in2[1])) * ((s32) in[1]) +
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((limb) ((s32) in2[0])) * ((s32) in[2]) +
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((limb) ((s32) in2[2])) * ((s32) in[0]);
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output[3] = ((limb) ((s32) in2[1])) * ((s32) in[2]) +
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((limb) ((s32) in2[2])) * ((s32) in[1]) +
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((limb) ((s32) in2[0])) * ((s32) in[3]) +
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((limb) ((s32) in2[3])) * ((s32) in[0]);
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output[4] = ((limb) ((s32) in2[2])) * ((s32) in[2]) +
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2 * (((limb) ((s32) in2[1])) * ((s32) in[3]) +
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((limb) ((s32) in2[3])) * ((s32) in[1])) +
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((limb) ((s32) in2[0])) * ((s32) in[4]) +
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((limb) ((s32) in2[4])) * ((s32) in[0]);
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output[5] = ((limb) ((s32) in2[2])) * ((s32) in[3]) +
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((limb) ((s32) in2[3])) * ((s32) in[2]) +
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((limb) ((s32) in2[1])) * ((s32) in[4]) +
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((limb) ((s32) in2[4])) * ((s32) in[1]) +
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((limb) ((s32) in2[0])) * ((s32) in[5]) +
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((limb) ((s32) in2[5])) * ((s32) in[0]);
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output[6] = 2 * (((limb) ((s32) in2[3])) * ((s32) in[3]) +
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((limb) ((s32) in2[1])) * ((s32) in[5]) +
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((limb) ((s32) in2[5])) * ((s32) in[1])) +
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((limb) ((s32) in2[2])) * ((s32) in[4]) +
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((limb) ((s32) in2[4])) * ((s32) in[2]) +
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((limb) ((s32) in2[0])) * ((s32) in[6]) +
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((limb) ((s32) in2[6])) * ((s32) in[0]);
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output[7] = ((limb) ((s32) in2[3])) * ((s32) in[4]) +
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((limb) ((s32) in2[4])) * ((s32) in[3]) +
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((limb) ((s32) in2[2])) * ((s32) in[5]) +
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((limb) ((s32) in2[5])) * ((s32) in[2]) +
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((limb) ((s32) in2[1])) * ((s32) in[6]) +
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((limb) ((s32) in2[6])) * ((s32) in[1]) +
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((limb) ((s32) in2[0])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[0]);
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output[8] = ((limb) ((s32) in2[4])) * ((s32) in[4]) +
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2 * (((limb) ((s32) in2[3])) * ((s32) in[5]) +
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((limb) ((s32) in2[5])) * ((s32) in[3]) +
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((limb) ((s32) in2[1])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[1])) +
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((limb) ((s32) in2[2])) * ((s32) in[6]) +
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((limb) ((s32) in2[6])) * ((s32) in[2]) +
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((limb) ((s32) in2[0])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[0]);
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output[9] = ((limb) ((s32) in2[4])) * ((s32) in[5]) +
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((limb) ((s32) in2[5])) * ((s32) in[4]) +
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((limb) ((s32) in2[3])) * ((s32) in[6]) +
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((limb) ((s32) in2[6])) * ((s32) in[3]) +
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((limb) ((s32) in2[2])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[2]) +
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((limb) ((s32) in2[1])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[1]) +
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((limb) ((s32) in2[0])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[0]);
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output[10] = 2 * (((limb) ((s32) in2[5])) * ((s32) in[5]) +
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((limb) ((s32) in2[3])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[3]) +
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((limb) ((s32) in2[1])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[1])) +
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((limb) ((s32) in2[4])) * ((s32) in[6]) +
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((limb) ((s32) in2[6])) * ((s32) in[4]) +
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((limb) ((s32) in2[2])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[2]);
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output[11] = ((limb) ((s32) in2[5])) * ((s32) in[6]) +
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((limb) ((s32) in2[6])) * ((s32) in[5]) +
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((limb) ((s32) in2[4])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[4]) +
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((limb) ((s32) in2[3])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[3]) +
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((limb) ((s32) in2[2])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[2]);
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output[12] = ((limb) ((s32) in2[6])) * ((s32) in[6]) +
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2 * (((limb) ((s32) in2[5])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[5]) +
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((limb) ((s32) in2[3])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[3])) +
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((limb) ((s32) in2[4])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[4]);
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output[13] = ((limb) ((s32) in2[6])) * ((s32) in[7]) +
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((limb) ((s32) in2[7])) * ((s32) in[6]) +
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((limb) ((s32) in2[5])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[5]) +
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((limb) ((s32) in2[4])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[4]);
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output[14] = 2 * (((limb) ((s32) in2[7])) * ((s32) in[7]) +
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((limb) ((s32) in2[5])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[5])) +
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((limb) ((s32) in2[6])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[6]);
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output[15] = ((limb) ((s32) in2[7])) * ((s32) in[8]) +
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((limb) ((s32) in2[8])) * ((s32) in[7]) +
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((limb) ((s32) in2[6])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[6]);
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output[16] = ((limb) ((s32) in2[8])) * ((s32) in[8]) +
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2 * (((limb) ((s32) in2[7])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[7]));
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output[17] = ((limb) ((s32) in2[8])) * ((s32) in[9]) +
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((limb) ((s32) in2[9])) * ((s32) in[8]);
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output[18] = 2 * ((limb) ((s32) in2[9])) * ((s32) in[9]);
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}
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/* Reduce a long form to a short form by taking the input mod 2^255 - 19.
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*
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* On entry: |output[i]| < 14*2^54
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* On exit: |output[0..8]| < 280*2^54 */
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static void freduce_degree(limb *output) {
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/* Each of these shifts and adds ends up multiplying the value by 19.
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*
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* For output[0..8], the absolute entry value is < 14*2^54 and we add, at
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* most, 19*14*2^54 thus, on exit, |output[0..8]| < 280*2^54. */
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output[8] += output[18] << 4;
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output[8] += output[18] << 1;
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output[8] += output[18];
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output[7] += output[17] << 4;
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output[7] += output[17] << 1;
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output[7] += output[17];
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output[6] += output[16] << 4;
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output[6] += output[16] << 1;
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output[6] += output[16];
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output[5] += output[15] << 4;
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output[5] += output[15] << 1;
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output[5] += output[15];
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output[4] += output[14] << 4;
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output[4] += output[14] << 1;
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output[4] += output[14];
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output[3] += output[13] << 4;
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output[3] += output[13] << 1;
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output[3] += output[13];
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output[2] += output[12] << 4;
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output[2] += output[12] << 1;
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output[2] += output[12];
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output[1] += output[11] << 4;
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output[1] += output[11] << 1;
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output[1] += output[11];
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output[0] += output[10] << 4;
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output[0] += output[10] << 1;
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output[0] += output[10];
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}
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#if (-1 & 3) != 3
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#error "This code only works on a two's complement system"
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#endif
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/* return v / 2^26, using only shifts and adds.
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*
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* On entry: v can take any value. */
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static limb
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div_by_2_26(const limb v)
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{
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/* High word of v; no shift needed. */
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const uint32_t highword = (uint32_t) (((uint64_t) v) >> 32);
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/* Set to all 1s if v was negative; else set to 0s. */
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const int32_t sign = ((int32_t) highword) >> 31;
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/* Set to 0x3ffffff if v was negative; else set to 0. */
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const int32_t roundoff = ((uint32_t) sign) >> 6;
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/* Should return v / (1<<26) */
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return (v + roundoff) >> 26;
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}
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/* return v / (2^25), using only shifts and adds.
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*
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* On entry: v can take any value. */
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static limb
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div_by_2_25(const limb v)
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{
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/* High word of v; no shift needed*/
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const uint32_t highword = (uint32_t) (((uint64_t) v) >> 32);
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/* Set to all 1s if v was negative; else set to 0s. */
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const int32_t sign = ((int32_t) highword) >> 31;
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/* Set to 0x1ffffff if v was negative; else set to 0. */
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const int32_t roundoff = ((uint32_t) sign) >> 7;
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/* Should return v / (1<<25) */
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return (v + roundoff) >> 25;
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}
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/* Reduce all coefficients of the short form input so that |x| < 2^26.
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*
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* On entry: |output[i]| < 280*2^54 */
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static void freduce_coefficients(limb *output) {
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unsigned i;
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output[10] = 0;
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for (i = 0; i < 10; i += 2) {
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limb over = div_by_2_26(output[i]);
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/* The entry condition (that |output[i]| < 280*2^54) means that over is, at
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* most, 280*2^28 in the first iteration of this loop. This is added to the
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* next limb and we can approximate the resulting bound of that limb by
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* 281*2^54. */
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output[i] -= over << 26;
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output[i+1] += over;
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/* For the first iteration, |output[i+1]| < 281*2^54, thus |over| <
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* 281*2^29. When this is added to the next limb, the resulting bound can
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* be approximated as 281*2^54.
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*
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* For subsequent iterations of the loop, 281*2^54 remains a conservative
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* bound and no overflow occurs. */
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over = div_by_2_25(output[i+1]);
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output[i+1] -= over << 25;
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output[i+2] += over;
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}
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/* Now |output[10]| < 281*2^29 and all other coefficients are reduced. */
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output[0] += output[10] << 4;
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output[0] += output[10] << 1;
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output[0] += output[10];
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output[10] = 0;
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/* Now output[1..9] are reduced, and |output[0]| < 2^26 + 19*281*2^29
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* So |over| will be no more than 2^16. */
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{
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limb over = div_by_2_26(output[0]);
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output[0] -= over << 26;
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output[1] += over;
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}
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/* Now output[0,2..9] are reduced, and |output[1]| < 2^25 + 2^16 < 2^26. The
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* bound on |output[1]| is sufficient to meet our needs. */
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}
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/* A helpful wrapper around fproduct: output = in * in2.
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*
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* On entry: |in[i]| < 2^27 and |in2[i]| < 2^27.
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*
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* output must be distinct to both inputs. The output is reduced degree
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* (indeed, one need only provide storage for 10 limbs) and |output[i]| < 2^26. */
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static void
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fmul(limb *output, const limb *in, const limb *in2) {
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limb t[19];
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fproduct(t, in, in2);
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/* |t[i]| < 14*2^54 */
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freduce_degree(t);
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freduce_coefficients(t);
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/* |t[i]| < 2^26 */
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memcpy(output, t, sizeof(limb) * 10);
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}
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/* Square a number: output = in**2
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*
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* output must be distinct from the input. The inputs are reduced coefficient
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||||
* form, the output is not.
|
||||
*
|
||||
* output[x] <= 14 * the largest product of the input limbs. */
|
||||
static void fsquare_inner(limb *output, const limb *in) {
|
||||
output[0] = ((limb) ((s32) in[0])) * ((s32) in[0]);
|
||||
output[1] = 2 * ((limb) ((s32) in[0])) * ((s32) in[1]);
|
||||
output[2] = 2 * (((limb) ((s32) in[1])) * ((s32) in[1]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[2]));
|
||||
output[3] = 2 * (((limb) ((s32) in[1])) * ((s32) in[2]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[3]));
|
||||
output[4] = ((limb) ((s32) in[2])) * ((s32) in[2]) +
|
||||
4 * ((limb) ((s32) in[1])) * ((s32) in[3]) +
|
||||
2 * ((limb) ((s32) in[0])) * ((s32) in[4]);
|
||||
output[5] = 2 * (((limb) ((s32) in[2])) * ((s32) in[3]) +
|
||||
((limb) ((s32) in[1])) * ((s32) in[4]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[5]));
|
||||
output[6] = 2 * (((limb) ((s32) in[3])) * ((s32) in[3]) +
|
||||
((limb) ((s32) in[2])) * ((s32) in[4]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[6]) +
|
||||
2 * ((limb) ((s32) in[1])) * ((s32) in[5]));
|
||||
output[7] = 2 * (((limb) ((s32) in[3])) * ((s32) in[4]) +
|
||||
((limb) ((s32) in[2])) * ((s32) in[5]) +
|
||||
((limb) ((s32) in[1])) * ((s32) in[6]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[7]));
|
||||
output[8] = ((limb) ((s32) in[4])) * ((s32) in[4]) +
|
||||
2 * (((limb) ((s32) in[2])) * ((s32) in[6]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[8]) +
|
||||
2 * (((limb) ((s32) in[1])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[3])) * ((s32) in[5])));
|
||||
output[9] = 2 * (((limb) ((s32) in[4])) * ((s32) in[5]) +
|
||||
((limb) ((s32) in[3])) * ((s32) in[6]) +
|
||||
((limb) ((s32) in[2])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[1])) * ((s32) in[8]) +
|
||||
((limb) ((s32) in[0])) * ((s32) in[9]));
|
||||
output[10] = 2 * (((limb) ((s32) in[5])) * ((s32) in[5]) +
|
||||
((limb) ((s32) in[4])) * ((s32) in[6]) +
|
||||
((limb) ((s32) in[2])) * ((s32) in[8]) +
|
||||
2 * (((limb) ((s32) in[3])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[1])) * ((s32) in[9])));
|
||||
output[11] = 2 * (((limb) ((s32) in[5])) * ((s32) in[6]) +
|
||||
((limb) ((s32) in[4])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[3])) * ((s32) in[8]) +
|
||||
((limb) ((s32) in[2])) * ((s32) in[9]));
|
||||
output[12] = ((limb) ((s32) in[6])) * ((s32) in[6]) +
|
||||
2 * (((limb) ((s32) in[4])) * ((s32) in[8]) +
|
||||
2 * (((limb) ((s32) in[5])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[3])) * ((s32) in[9])));
|
||||
output[13] = 2 * (((limb) ((s32) in[6])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[5])) * ((s32) in[8]) +
|
||||
((limb) ((s32) in[4])) * ((s32) in[9]));
|
||||
output[14] = 2 * (((limb) ((s32) in[7])) * ((s32) in[7]) +
|
||||
((limb) ((s32) in[6])) * ((s32) in[8]) +
|
||||
2 * ((limb) ((s32) in[5])) * ((s32) in[9]));
|
||||
output[15] = 2 * (((limb) ((s32) in[7])) * ((s32) in[8]) +
|
||||
((limb) ((s32) in[6])) * ((s32) in[9]));
|
||||
output[16] = ((limb) ((s32) in[8])) * ((s32) in[8]) +
|
||||
4 * ((limb) ((s32) in[7])) * ((s32) in[9]);
|
||||
output[17] = 2 * ((limb) ((s32) in[8])) * ((s32) in[9]);
|
||||
output[18] = 2 * ((limb) ((s32) in[9])) * ((s32) in[9]);
|
||||
}
|
||||
|
||||
/* fsquare sets output = in^2.
|
||||
*
|
||||
* On entry: The |in| argument is in reduced coefficients form and |in[i]| <
|
||||
* 2^27.
|
||||
*
|
||||
* On exit: The |output| argument is in reduced coefficients form (indeed, one
|
||||
* need only provide storage for 10 limbs) and |out[i]| < 2^26. */
|
||||
static void
|
||||
fsquare(limb *output, const limb *in) {
|
||||
limb t[19];
|
||||
fsquare_inner(t, in);
|
||||
/* |t[i]| < 14*2^54 because the largest product of two limbs will be <
|
||||
* 2^(27+27) and fsquare_inner adds together, at most, 14 of those
|
||||
* products. */
|
||||
freduce_degree(t);
|
||||
freduce_coefficients(t);
|
||||
/* |t[i]| < 2^26 */
|
||||
memcpy(output, t, sizeof(limb) * 10);
|
||||
}
|
||||
|
||||
/* Take a little-endian, 32-byte number and expand it into polynomial form */
|
||||
static void
|
||||
fexpand(limb *output, const u8 *input) {
|
||||
#define F(n,start,shift,mask) \
|
||||
output[n] = ((((limb) input[start + 0]) | \
|
||||
((limb) input[start + 1]) << 8 | \
|
||||
((limb) input[start + 2]) << 16 | \
|
||||
((limb) input[start + 3]) << 24) >> shift) & mask;
|
||||
F(0, 0, 0, 0x3ffffff);
|
||||
F(1, 3, 2, 0x1ffffff);
|
||||
F(2, 6, 3, 0x3ffffff);
|
||||
F(3, 9, 5, 0x1ffffff);
|
||||
F(4, 12, 6, 0x3ffffff);
|
||||
F(5, 16, 0, 0x1ffffff);
|
||||
F(6, 19, 1, 0x3ffffff);
|
||||
F(7, 22, 3, 0x1ffffff);
|
||||
F(8, 25, 4, 0x3ffffff);
|
||||
F(9, 28, 6, 0x1ffffff);
|
||||
#undef F
|
||||
}
|
||||
|
||||
#if (-32 >> 1) != -16
|
||||
#error "This code only works when >> does sign-extension on negative numbers"
|
||||
#endif
|
||||
|
||||
/* s32_eq returns 0xffffffff iff a == b and zero otherwise. */
|
||||
static s32 s32_eq(s32 a, s32 b) {
|
||||
a = ~(a ^ b);
|
||||
a &= a << 16;
|
||||
a &= a << 8;
|
||||
a &= a << 4;
|
||||
a &= a << 2;
|
||||
a &= a << 1;
|
||||
return a >> 31;
|
||||
}
|
||||
|
||||
/* s32_gte returns 0xffffffff if a >= b and zero otherwise, where a and b are
|
||||
* both non-negative. */
|
||||
static s32 s32_gte(s32 a, s32 b) {
|
||||
a -= b;
|
||||
/* a >= 0 iff a >= b. */
|
||||
return ~(a >> 31);
|
||||
}
|
||||
|
||||
/* Take a fully reduced polynomial form number and contract it into a
|
||||
* little-endian, 32-byte array.
|
||||
*
|
||||
* On entry: |input_limbs[i]| < 2^26 */
|
||||
static void
|
||||
fcontract(u8 *output, limb *input_limbs) {
|
||||
int i;
|
||||
int j;
|
||||
s32 input[10];
|
||||
s32 mask;
|
||||
|
||||
/* |input_limbs[i]| < 2^26, so it's valid to convert to an s32. */
|
||||
for (i = 0; i < 10; i++) {
|
||||
input[i] = input_limbs[i];
|
||||
}
|
||||
|
||||
for (j = 0; j < 2; ++j) {
|
||||
for (i = 0; i < 9; ++i) {
|
||||
if ((i & 1) == 1) {
|
||||
/* This calculation is a time-invariant way to make input[i]
|
||||
* non-negative by borrowing from the next-larger limb. */
|
||||
const s32 mask = input[i] >> 31;
|
||||
const s32 carry = -((input[i] & mask) >> 25);
|
||||
input[i] = input[i] + (carry << 25);
|
||||
input[i+1] = input[i+1] - carry;
|
||||
} else {
|
||||
const s32 mask = input[i] >> 31;
|
||||
const s32 carry = -((input[i] & mask) >> 26);
|
||||
input[i] = input[i] + (carry << 26);
|
||||
input[i+1] = input[i+1] - carry;
|
||||
}
|
||||
}
|
||||
|
||||
/* There's no greater limb for input[9] to borrow from, but we can multiply
|
||||
* by 19 and borrow from input[0], which is valid mod 2^255-19. */
|
||||
{
|
||||
const s32 mask = input[9] >> 31;
|
||||
const s32 carry = -((input[9] & mask) >> 25);
|
||||
input[9] = input[9] + (carry << 25);
|
||||
input[0] = input[0] - (carry * 19);
|
||||
}
|
||||
|
||||
/* After the first iteration, input[1..9] are non-negative and fit within
|
||||
* 25 or 26 bits, depending on position. However, input[0] may be
|
||||
* negative. */
|
||||
}
|
||||
|
||||
/* The first borrow-propagation pass above ended with every limb
|
||||
except (possibly) input[0] non-negative.
|
||||
|
||||
If input[0] was negative after the first pass, then it was because of a
|
||||
carry from input[9]. On entry, input[9] < 2^26 so the carry was, at most,
|
||||
one, since (2**26-1) >> 25 = 1. Thus input[0] >= -19.
|
||||
|
||||
In the second pass, each limb is decreased by at most one. Thus the second
|
||||
borrow-propagation pass could only have wrapped around to decrease
|
||||
input[0] again if the first pass left input[0] negative *and* input[1]
|
||||
through input[9] were all zero. In that case, input[1] is now 2^25 - 1,
|
||||
and this last borrow-propagation step will leave input[1] non-negative. */
|
||||
{
|
||||
const s32 mask = input[0] >> 31;
|
||||
const s32 carry = -((input[0] & mask) >> 26);
|
||||
input[0] = input[0] + (carry << 26);
|
||||
input[1] = input[1] - carry;
|
||||
}
|
||||
|
||||
/* All input[i] are now non-negative. However, there might be values between
|
||||
* 2^25 and 2^26 in a limb which is, nominally, 25 bits wide. */
|
||||
for (j = 0; j < 2; j++) {
|
||||
for (i = 0; i < 9; i++) {
|
||||
if ((i & 1) == 1) {
|
||||
const s32 carry = input[i] >> 25;
|
||||
input[i] &= 0x1ffffff;
|
||||
input[i+1] += carry;
|
||||
} else {
|
||||
const s32 carry = input[i] >> 26;
|
||||
input[i] &= 0x3ffffff;
|
||||
input[i+1] += carry;
|
||||
}
|
||||
}
|
||||
|
||||
{
|
||||
const s32 carry = input[9] >> 25;
|
||||
input[9] &= 0x1ffffff;
|
||||
input[0] += 19*carry;
|
||||
}
|
||||
}
|
||||
|
||||
/* If the first carry-chain pass, just above, ended up with a carry from
|
||||
* input[9], and that caused input[0] to be out-of-bounds, then input[0] was
|
||||
* < 2^26 + 2*19, because the carry was, at most, two.
|
||||
*
|
||||
* If the second pass carried from input[9] again then input[0] is < 2*19 and
|
||||
* the input[9] -> input[0] carry didn't push input[0] out of bounds. */
|
||||
|
||||
/* It still remains the case that input might be between 2^255-19 and 2^255.
|
||||
* In this case, input[1..9] must take their maximum value and input[0] must
|
||||
* be >= (2^255-19) & 0x3ffffff, which is 0x3ffffed. */
|
||||
mask = s32_gte(input[0], 0x3ffffed);
|
||||
for (i = 1; i < 10; i++) {
|
||||
if ((i & 1) == 1) {
|
||||
mask &= s32_eq(input[i], 0x1ffffff);
|
||||
} else {
|
||||
mask &= s32_eq(input[i], 0x3ffffff);
|
||||
}
|
||||
}
|
||||
|
||||
/* mask is either 0xffffffff (if input >= 2^255-19) and zero otherwise. Thus
|
||||
* this conditionally subtracts 2^255-19. */
|
||||
input[0] -= mask & 0x3ffffed;
|
||||
|
||||
for (i = 1; i < 10; i++) {
|
||||
if ((i & 1) == 1) {
|
||||
input[i] -= mask & 0x1ffffff;
|
||||
} else {
|
||||
input[i] -= mask & 0x3ffffff;
|
||||
}
|
||||
}
|
||||
|
||||
input[1] <<= 2;
|
||||
input[2] <<= 3;
|
||||
input[3] <<= 5;
|
||||
input[4] <<= 6;
|
||||
input[6] <<= 1;
|
||||
input[7] <<= 3;
|
||||
input[8] <<= 4;
|
||||
input[9] <<= 6;
|
||||
#define F(i, s) \
|
||||
output[s+0] |= input[i] & 0xff; \
|
||||
output[s+1] = (input[i] >> 8) & 0xff; \
|
||||
output[s+2] = (input[i] >> 16) & 0xff; \
|
||||
output[s+3] = (input[i] >> 24) & 0xff;
|
||||
output[0] = 0;
|
||||
output[16] = 0;
|
||||
F(0,0);
|
||||
F(1,3);
|
||||
F(2,6);
|
||||
F(3,9);
|
||||
F(4,12);
|
||||
F(5,16);
|
||||
F(6,19);
|
||||
F(7,22);
|
||||
F(8,25);
|
||||
F(9,28);
|
||||
#undef F
|
||||
}
|
||||
|
||||
/* Input: Q, Q', Q-Q'
|
||||
* Output: 2Q, Q+Q'
|
||||
*
|
||||
* x2 z3: long form
|
||||
* x3 z3: long form
|
||||
* x z: short form, destroyed
|
||||
* xprime zprime: short form, destroyed
|
||||
* qmqp: short form, preserved
|
||||
*
|
||||
* On entry and exit, the absolute value of the limbs of all inputs and outputs
|
||||
* are < 2^26. */
|
||||
static void fmonty(limb *x2, limb *z2, /* output 2Q */
|
||||
limb *x3, limb *z3, /* output Q + Q' */
|
||||
limb *x, limb *z, /* input Q */
|
||||
limb *xprime, limb *zprime, /* input Q' */
|
||||
const limb *qmqp /* input Q - Q' */) {
|
||||
limb origx[10], origxprime[10], zzz[19], xx[19], zz[19], xxprime[19],
|
||||
zzprime[19], zzzprime[19], xxxprime[19];
|
||||
|
||||
memcpy(origx, x, 10 * sizeof(limb));
|
||||
fsum(x, z);
|
||||
/* |x[i]| < 2^27 */
|
||||
fdifference(z, origx); /* does x - z */
|
||||
/* |z[i]| < 2^27 */
|
||||
|
||||
memcpy(origxprime, xprime, sizeof(limb) * 10);
|
||||
fsum(xprime, zprime);
|
||||
/* |xprime[i]| < 2^27 */
|
||||
fdifference(zprime, origxprime);
|
||||
/* |zprime[i]| < 2^27 */
|
||||
fproduct(xxprime, xprime, z);
|
||||
/* |xxprime[i]| < 14*2^54: the largest product of two limbs will be <
|
||||
* 2^(27+27) and fproduct adds together, at most, 14 of those products.
|
||||
* (Approximating that to 2^58 doesn't work out.) */
|
||||
fproduct(zzprime, x, zprime);
|
||||
/* |zzprime[i]| < 14*2^54 */
|
||||
freduce_degree(xxprime);
|
||||
freduce_coefficients(xxprime);
|
||||
/* |xxprime[i]| < 2^26 */
|
||||
freduce_degree(zzprime);
|
||||
freduce_coefficients(zzprime);
|
||||
/* |zzprime[i]| < 2^26 */
|
||||
memcpy(origxprime, xxprime, sizeof(limb) * 10);
|
||||
fsum(xxprime, zzprime);
|
||||
/* |xxprime[i]| < 2^27 */
|
||||
fdifference(zzprime, origxprime);
|
||||
/* |zzprime[i]| < 2^27 */
|
||||
fsquare(xxxprime, xxprime);
|
||||
/* |xxxprime[i]| < 2^26 */
|
||||
fsquare(zzzprime, zzprime);
|
||||
/* |zzzprime[i]| < 2^26 */
|
||||
fproduct(zzprime, zzzprime, qmqp);
|
||||
/* |zzprime[i]| < 14*2^52 */
|
||||
freduce_degree(zzprime);
|
||||
freduce_coefficients(zzprime);
|
||||
/* |zzprime[i]| < 2^26 */
|
||||
memcpy(x3, xxxprime, sizeof(limb) * 10);
|
||||
memcpy(z3, zzprime, sizeof(limb) * 10);
|
||||
|
||||
fsquare(xx, x);
|
||||
/* |xx[i]| < 2^26 */
|
||||
fsquare(zz, z);
|
||||
/* |zz[i]| < 2^26 */
|
||||
fproduct(x2, xx, zz);
|
||||
/* |x2[i]| < 14*2^52 */
|
||||
freduce_degree(x2);
|
||||
freduce_coefficients(x2);
|
||||
/* |x2[i]| < 2^26 */
|
||||
fdifference(zz, xx); /* does zz = xx - zz */
|
||||
/* |zz[i]| < 2^27 */
|
||||
memset(zzz + 10, 0, sizeof(limb) * 9);
|
||||
fscalar_product(zzz, zz, 121665);
|
||||
/* |zzz[i]| < 2^(27+17) */
|
||||
/* No need to call freduce_degree here:
|
||||
fscalar_product doesn't increase the degree of its input. */
|
||||
freduce_coefficients(zzz);
|
||||
/* |zzz[i]| < 2^26 */
|
||||
fsum(zzz, xx);
|
||||
/* |zzz[i]| < 2^27 */
|
||||
fproduct(z2, zz, zzz);
|
||||
/* |z2[i]| < 14*2^(26+27) */
|
||||
freduce_degree(z2);
|
||||
freduce_coefficients(z2);
|
||||
/* |z2|i| < 2^26 */
|
||||
}
|
||||
|
||||
/* Conditionally swap two reduced-form limb arrays if 'iswap' is 1, but leave
|
||||
* them unchanged if 'iswap' is 0. Runs in data-invariant time to avoid
|
||||
* side-channel attacks.
|
||||
*
|
||||
* NOTE that this function requires that 'iswap' be 1 or 0; other values give
|
||||
* wrong results. Also, the two limb arrays must be in reduced-coefficient,
|
||||
* reduced-degree form: the values in a[10..19] or b[10..19] aren't swapped,
|
||||
* and all all values in a[0..9],b[0..9] must have magnitude less than
|
||||
* INT32_MAX. */
|
||||
static void
|
||||
swap_conditional(limb a[19], limb b[19], limb iswap) {
|
||||
unsigned i;
|
||||
const s32 swap = (s32) -iswap;
|
||||
|
||||
for (i = 0; i < 10; ++i) {
|
||||
const s32 x = swap & ( ((s32)a[i]) ^ ((s32)b[i]) );
|
||||
a[i] = ((s32)a[i]) ^ x;
|
||||
b[i] = ((s32)b[i]) ^ x;
|
||||
}
|
||||
}
|
||||
|
||||
/* Calculates nQ where Q is the x-coordinate of a point on the curve
|
||||
*
|
||||
* resultx/resultz: the x coordinate of the resulting curve point (short form)
|
||||
* n: a little endian, 32-byte number
|
||||
* q: a point of the curve (short form) */
|
||||
static void
|
||||
cmult(limb *resultx, limb *resultz, const u8 *n, const limb *q) {
|
||||
limb a[19] = {0}, b[19] = {1}, c[19] = {1}, d[19] = {0};
|
||||
limb *nqpqx = a, *nqpqz = b, *nqx = c, *nqz = d, *t;
|
||||
limb e[19] = {0}, f[19] = {1}, g[19] = {0}, h[19] = {1};
|
||||
limb *nqpqx2 = e, *nqpqz2 = f, *nqx2 = g, *nqz2 = h;
|
||||
|
||||
unsigned i, j;
|
||||
|
||||
memcpy(nqpqx, q, sizeof(limb) * 10);
|
||||
|
||||
for (i = 0; i < 32; ++i) {
|
||||
u8 byte = n[31 - i];
|
||||
for (j = 0; j < 8; ++j) {
|
||||
const limb bit = byte >> 7;
|
||||
|
||||
swap_conditional(nqx, nqpqx, bit);
|
||||
swap_conditional(nqz, nqpqz, bit);
|
||||
fmonty(nqx2, nqz2,
|
||||
nqpqx2, nqpqz2,
|
||||
nqx, nqz,
|
||||
nqpqx, nqpqz,
|
||||
q);
|
||||
swap_conditional(nqx2, nqpqx2, bit);
|
||||
swap_conditional(nqz2, nqpqz2, bit);
|
||||
|
||||
t = nqx;
|
||||
nqx = nqx2;
|
||||
nqx2 = t;
|
||||
t = nqz;
|
||||
nqz = nqz2;
|
||||
nqz2 = t;
|
||||
t = nqpqx;
|
||||
nqpqx = nqpqx2;
|
||||
nqpqx2 = t;
|
||||
t = nqpqz;
|
||||
nqpqz = nqpqz2;
|
||||
nqpqz2 = t;
|
||||
|
||||
byte <<= 1;
|
||||
}
|
||||
}
|
||||
|
||||
memcpy(resultx, nqx, sizeof(limb) * 10);
|
||||
memcpy(resultz, nqz, sizeof(limb) * 10);
|
||||
}
|
||||
|
||||
static void
|
||||
crecip(limb *out, const limb *z) {
|
||||
limb z2[10];
|
||||
limb z9[10];
|
||||
limb z11[10];
|
||||
limb z2_5_0[10];
|
||||
limb z2_10_0[10];
|
||||
limb z2_20_0[10];
|
||||
limb z2_50_0[10];
|
||||
limb z2_100_0[10];
|
||||
limb t0[10];
|
||||
limb t1[10];
|
||||
int i;
|
||||
|
||||
/* 2 */ fsquare(z2,z);
|
||||
/* 4 */ fsquare(t1,z2);
|
||||
/* 8 */ fsquare(t0,t1);
|
||||
/* 9 */ fmul(z9,t0,z);
|
||||
/* 11 */ fmul(z11,z9,z2);
|
||||
/* 22 */ fsquare(t0,z11);
|
||||
/* 2^5 - 2^0 = 31 */ fmul(z2_5_0,t0,z9);
|
||||
|
||||
/* 2^6 - 2^1 */ fsquare(t0,z2_5_0);
|
||||
/* 2^7 - 2^2 */ fsquare(t1,t0);
|
||||
/* 2^8 - 2^3 */ fsquare(t0,t1);
|
||||
/* 2^9 - 2^4 */ fsquare(t1,t0);
|
||||
/* 2^10 - 2^5 */ fsquare(t0,t1);
|
||||
/* 2^10 - 2^0 */ fmul(z2_10_0,t0,z2_5_0);
|
||||
|
||||
/* 2^11 - 2^1 */ fsquare(t0,z2_10_0);
|
||||
/* 2^12 - 2^2 */ fsquare(t1,t0);
|
||||
/* 2^20 - 2^10 */ for (i = 2;i < 10;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
|
||||
/* 2^20 - 2^0 */ fmul(z2_20_0,t1,z2_10_0);
|
||||
|
||||
/* 2^21 - 2^1 */ fsquare(t0,z2_20_0);
|
||||
/* 2^22 - 2^2 */ fsquare(t1,t0);
|
||||
/* 2^40 - 2^20 */ for (i = 2;i < 20;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
|
||||
/* 2^40 - 2^0 */ fmul(t0,t1,z2_20_0);
|
||||
|
||||
/* 2^41 - 2^1 */ fsquare(t1,t0);
|
||||
/* 2^42 - 2^2 */ fsquare(t0,t1);
|
||||
/* 2^50 - 2^10 */ for (i = 2;i < 10;i += 2) { fsquare(t1,t0); fsquare(t0,t1); }
|
||||
/* 2^50 - 2^0 */ fmul(z2_50_0,t0,z2_10_0);
|
||||
|
||||
/* 2^51 - 2^1 */ fsquare(t0,z2_50_0);
|
||||
/* 2^52 - 2^2 */ fsquare(t1,t0);
|
||||
/* 2^100 - 2^50 */ for (i = 2;i < 50;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
|
||||
/* 2^100 - 2^0 */ fmul(z2_100_0,t1,z2_50_0);
|
||||
|
||||
/* 2^101 - 2^1 */ fsquare(t1,z2_100_0);
|
||||
/* 2^102 - 2^2 */ fsquare(t0,t1);
|
||||
/* 2^200 - 2^100 */ for (i = 2;i < 100;i += 2) { fsquare(t1,t0); fsquare(t0,t1); }
|
||||
/* 2^200 - 2^0 */ fmul(t1,t0,z2_100_0);
|
||||
|
||||
/* 2^201 - 2^1 */ fsquare(t0,t1);
|
||||
/* 2^202 - 2^2 */ fsquare(t1,t0);
|
||||
/* 2^250 - 2^50 */ for (i = 2;i < 50;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
|
||||
/* 2^250 - 2^0 */ fmul(t0,t1,z2_50_0);
|
||||
|
||||
/* 2^251 - 2^1 */ fsquare(t1,t0);
|
||||
/* 2^252 - 2^2 */ fsquare(t0,t1);
|
||||
/* 2^253 - 2^3 */ fsquare(t1,t0);
|
||||
/* 2^254 - 2^4 */ fsquare(t0,t1);
|
||||
/* 2^255 - 2^5 */ fsquare(t1,t0);
|
||||
/* 2^255 - 21 */ fmul(out,t1,z11);
|
||||
}
|
||||
|
||||
int
|
||||
curve25519_donna(u8 *mypublic, const u8 *secret, const u8 *basepoint) {
|
||||
limb bp[10], x[10], z[11], zmone[10];
|
||||
uint8_t e[32];
|
||||
int i;
|
||||
|
||||
for (i = 0; i < 32; ++i) e[i] = secret[i];
|
||||
e[0] &= 248;
|
||||
e[31] &= 127;
|
||||
e[31] |= 64;
|
||||
|
||||
fexpand(bp, basepoint);
|
||||
cmult(x, z, e, bp);
|
||||
crecip(zmone, z);
|
||||
fmul(z, x, zmone);
|
||||
fcontract(mypublic, z);
|
||||
return 0;
|
||||
}
|
||||
252
enchive.c
252
enchive.c
|
|
@ -1,17 +1,253 @@
|
|||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <stdarg.h>
|
||||
|
||||
#define OPTPARSE_IMPLEMENTATION
|
||||
#include "optparse.h"
|
||||
#include "chacha.h"
|
||||
|
||||
int
|
||||
main(void)
|
||||
static void
|
||||
fatal(const char *fmt, ...)
|
||||
{
|
||||
static u8 key[32];
|
||||
static u8 iv[8];
|
||||
static u8 buffer[2][4096 * 4096];
|
||||
size_t in = fread(buffer[0], 1, sizeof(buffer[0]), stdin);
|
||||
va_list ap;
|
||||
va_start(ap, fmt);
|
||||
fprintf(stderr, "enchive: ");
|
||||
vfprintf(stderr, fmt, ap);
|
||||
fputc('\n', stderr);
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
int curve25519_donna(unsigned char *p,
|
||||
const unsigned char *s,
|
||||
const unsigned char *b);
|
||||
|
||||
static void
|
||||
secure_entropy(void *buf, size_t len)
|
||||
{
|
||||
FILE *r = fopen("/dev/urandom", "rb");
|
||||
if (!r)
|
||||
fatal("failed to open /dev/urandom");
|
||||
if (!fread(buf, len, 1, r))
|
||||
fatal("failed to gather entropy");
|
||||
fclose(r);
|
||||
}
|
||||
|
||||
static void
|
||||
generate_secret(unsigned char *s)
|
||||
{
|
||||
secure_entropy(s, 32);
|
||||
s[0] &= 248;
|
||||
s[31] &= 127;
|
||||
s[31] |= 64;
|
||||
}
|
||||
|
||||
static void
|
||||
compute_public(unsigned char *p, const unsigned char *s)
|
||||
{
|
||||
static const unsigned char b[32] = {9};
|
||||
curve25519_donna(p, s, b);
|
||||
}
|
||||
|
||||
static void
|
||||
compute_shared(unsigned char *sh,
|
||||
const unsigned char *s,
|
||||
const unsigned char *p)
|
||||
{
|
||||
curve25519_donna(sh, s, p);
|
||||
}
|
||||
|
||||
static void
|
||||
symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
|
||||
{
|
||||
static u8 buffer[2][64 * 1024];
|
||||
chacha_ctx ctx[1];
|
||||
chacha_keysetup(ctx, key, 256);
|
||||
chacha_ivsetup(ctx, iv);
|
||||
chacha_encrypt_bytes(ctx, buffer[0], buffer[1], in);
|
||||
fwrite(buffer[1], 1, in, stdout);
|
||||
|
||||
for (;;) {
|
||||
size_t z = fread(buffer[0], 1, sizeof(buffer[0]), in);
|
||||
if (!z) {
|
||||
if (ferror(in))
|
||||
fatal("error reading source file");
|
||||
break;
|
||||
}
|
||||
chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z);
|
||||
if (!fwrite(buffer[1], z, 1, out))
|
||||
fatal("error writing destination file");
|
||||
}
|
||||
}
|
||||
|
||||
static const char *
|
||||
default_pubfile(void)
|
||||
{
|
||||
return "key.pub";
|
||||
}
|
||||
|
||||
static const char *
|
||||
default_secfile(void)
|
||||
{
|
||||
return "key.sec";
|
||||
}
|
||||
|
||||
static void
|
||||
load_key(const char *file, unsigned char *key)
|
||||
{
|
||||
FILE *f = fopen(file, "rb");
|
||||
if (!f)
|
||||
fatal("failed to open key file, %s", file);
|
||||
if (!fread(key, 32, 1, f))
|
||||
fatal("failed to read key file, %s", file);
|
||||
fclose(f);
|
||||
}
|
||||
|
||||
static void
|
||||
write_key(const char *file, const unsigned char *key)
|
||||
{
|
||||
FILE *f = fopen(file, "wb");
|
||||
if (!f)
|
||||
fatal("failed to open key file, %s", file);
|
||||
if (!fwrite(key, 32, 1, f))
|
||||
fatal("failed to write key file, %s", file);
|
||||
fclose(f);
|
||||
}
|
||||
|
||||
static void
|
||||
command_keygen(struct optparse *options)
|
||||
{
|
||||
static const struct optparse_long keygen[] = {
|
||||
{0}
|
||||
};
|
||||
|
||||
const char *pubfile = default_pubfile();
|
||||
const char *secfile = default_secfile();
|
||||
unsigned char public[32];
|
||||
unsigned char secret[32];
|
||||
|
||||
int option;
|
||||
while ((option = optparse_long(options, keygen, 0)) != -1) {
|
||||
switch (option) {
|
||||
}
|
||||
}
|
||||
|
||||
generate_secret(secret);
|
||||
compute_public(public, secret);
|
||||
write_key(pubfile, public);
|
||||
write_key(secfile, secret);
|
||||
}
|
||||
|
||||
static void
|
||||
command_archive(struct optparse *options)
|
||||
{
|
||||
static const struct optparse_long archive[] = {
|
||||
{0}
|
||||
};
|
||||
|
||||
const char *pubfile = default_pubfile();
|
||||
unsigned char public[32];
|
||||
unsigned char esecret[32];
|
||||
unsigned char epublic[32];
|
||||
unsigned char shared[32];
|
||||
unsigned char iv[8];
|
||||
|
||||
int option;
|
||||
while ((option = optparse_long(options, archive, 0)) != -1) {
|
||||
switch (option) {
|
||||
}
|
||||
}
|
||||
|
||||
load_key(pubfile, public);
|
||||
|
||||
/* Generare ephemeral keypair. */
|
||||
generate_secret(esecret);
|
||||
compute_public(epublic, esecret);
|
||||
|
||||
compute_shared(shared, esecret, public);
|
||||
secure_entropy(iv, sizeof(iv));
|
||||
if (!fwrite(iv, sizeof(iv), 1, stdout))
|
||||
fatal("failed to write IV to archive");
|
||||
if (!fwrite(epublic, sizeof(epublic), 1, stdout))
|
||||
fatal("failed to write ephemeral key to archive");
|
||||
symmetric_encrypt(stdin, stdout, shared, iv);
|
||||
}
|
||||
|
||||
static void
|
||||
command_extract(struct optparse *options)
|
||||
{
|
||||
static const struct optparse_long extract[] = {
|
||||
{0}
|
||||
};
|
||||
|
||||
const char *secfile = default_secfile();
|
||||
unsigned char secret[32];
|
||||
unsigned char epublic[32];
|
||||
unsigned char shared[32];
|
||||
unsigned char iv[8];
|
||||
|
||||
int option;
|
||||
while ((option = optparse_long(options, extract, 0)) != -1) {
|
||||
switch (option) {
|
||||
}
|
||||
}
|
||||
|
||||
load_key(secfile, secret);
|
||||
|
||||
if (!(fread(iv, sizeof(iv), 1, stdin)))
|
||||
fatal("failed to read IV from archive");
|
||||
if (!(fread(epublic, sizeof(epublic), 1, stdin)))
|
||||
fatal("failed to read ephemeral key from archive");
|
||||
compute_shared(shared, secret, epublic);
|
||||
symmetric_encrypt(stdin, stdout, shared, iv);
|
||||
}
|
||||
|
||||
static void
|
||||
command_help(struct optparse *options)
|
||||
{
|
||||
static const struct optparse_long help[] = {
|
||||
{0}
|
||||
};
|
||||
|
||||
int option;
|
||||
while ((option = optparse_long(options, help, 0)) != -1) {
|
||||
switch (option) {
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
int
|
||||
main(int argc, char **argv)
|
||||
{
|
||||
static const struct optparse_long global[] = {
|
||||
{0}
|
||||
};
|
||||
|
||||
int option;
|
||||
char *command;
|
||||
struct optparse options[1];
|
||||
optparse_init(options, argv);
|
||||
options->permute = 0;
|
||||
(void)argc;
|
||||
|
||||
while ((option = optparse_long(options, global, 0)) != -1) {
|
||||
switch (option) {
|
||||
}
|
||||
}
|
||||
|
||||
command = optparse_arg(options);
|
||||
options->permute = 1;
|
||||
|
||||
if (!command) {
|
||||
command_help(options);
|
||||
fatal("missing command");
|
||||
} else if (strcmp(command, "keygen") == 0) {
|
||||
command_keygen(options);
|
||||
} else if (strcmp(command, "archive") == 0) {
|
||||
command_archive(options);
|
||||
} else if (strcmp(command, "extract") == 0) {
|
||||
command_extract(options);
|
||||
} else {
|
||||
command_help(options);
|
||||
fatal("unknown command, %s", command);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -0,0 +1,401 @@
|
|||
/* Optparse --- portable, reentrant, embeddable, getopt-like option parser
|
||||
*
|
||||
* This is free and unencumbered software released into the public domain.
|
||||
*
|
||||
* To get the implementation, define OPTPARSE_IMPLEMENTATION.
|
||||
* Optionally define OPTPARSE_API to control the API's visibility
|
||||
* and/or linkage (static, __attribute__, __declspec).
|
||||
*
|
||||
* The POSIX getopt() option parser has three fatal flaws. These flaws
|
||||
* are solved by Optparse.
|
||||
*
|
||||
* 1) Parser state is stored entirely in global variables, some of
|
||||
* which are static and inaccessible. This means only one thread can
|
||||
* use getopt(). It also means it's not possible to recursively parse
|
||||
* nested sub-arguments while in the middle of argument parsing.
|
||||
* Optparse fixes this by storing all state on a local struct.
|
||||
*
|
||||
* 2) The POSIX standard provides no way to properly reset the parser.
|
||||
* This means for portable code that getopt() is only good for one
|
||||
* run, over one argv with one option string. It also means subcommand
|
||||
* options cannot be processed with getopt(). Most implementations
|
||||
* provide a method to reset the parser, but it's not portable.
|
||||
* Optparse provides an optparse_arg() function for stepping over
|
||||
* subcommands and continuing parsing of options with another option
|
||||
* string. The Optparse struct itself can be passed around to
|
||||
* subcommand handlers for additional subcommand option parsing. A
|
||||
* full reset can be achieved by with an additional optparse_init().
|
||||
*
|
||||
* 3) Error messages are printed to stderr. This can be disabled with
|
||||
* opterr, but the messages themselves are still inaccessible.
|
||||
* Optparse solves this by writing an error message in its errmsg
|
||||
* field. The downside to Optparse is that this error message will
|
||||
* always be in English rather than the current locale.
|
||||
*
|
||||
* Optparse should be familiar with anyone accustomed to getopt(), and
|
||||
* it could be a nearly drop-in replacement. The option string is the
|
||||
* same and the fields have the same names as the getopt() global
|
||||
* variables (optarg, optind, optopt).
|
||||
*
|
||||
* Optparse also supports GNU-style long options with optparse_long().
|
||||
* The interface is slightly different and simpler than getopt_long().
|
||||
*
|
||||
* By default, argv is permuted as it is parsed, moving non-option
|
||||
* arguments to the end. This can be disabled by setting the `permute`
|
||||
* field to 0 after initialization.
|
||||
*/
|
||||
#ifndef OPTPARSE_H
|
||||
#define OPTPARSE_H
|
||||
|
||||
#ifndef OPTPARSE_API
|
||||
# define OPTPARSE_API
|
||||
#endif
|
||||
|
||||
struct optparse {
|
||||
char **argv;
|
||||
int permute;
|
||||
int optind;
|
||||
int optopt;
|
||||
char *optarg;
|
||||
char errmsg[64];
|
||||
int subopt;
|
||||
};
|
||||
|
||||
enum optparse_argtype {
|
||||
OPTPARSE_NONE,
|
||||
OPTPARSE_REQUIRED,
|
||||
OPTPARSE_OPTIONAL
|
||||
};
|
||||
|
||||
struct optparse_long {
|
||||
const char *longname;
|
||||
int shortname;
|
||||
enum optparse_argtype argtype;
|
||||
};
|
||||
|
||||
/**
|
||||
* Initializes the parser state.
|
||||
*/
|
||||
OPTPARSE_API
|
||||
void optparse_init(struct optparse *options, char **argv);
|
||||
|
||||
/**
|
||||
* Read the next option in the argv array.
|
||||
* @param optstring a getopt()-formatted option string.
|
||||
* @return the next option character, -1 for done, or '?' for error
|
||||
*
|
||||
* Just like getopt(), a character followed by no colons means no
|
||||
* argument. One colon means the option has a required argument. Two
|
||||
* colons means the option takes an optional argument.
|
||||
*/
|
||||
OPTPARSE_API
|
||||
int optparse(struct optparse *options, const char *optstring);
|
||||
|
||||
/**
|
||||
* Handles GNU-style long options in addition to getopt() options.
|
||||
* This works a lot like GNU's getopt_long(). The last option in
|
||||
* longopts must be all zeros, marking the end of the array. The
|
||||
* longindex argument may be NULL.
|
||||
*/
|
||||
OPTPARSE_API
|
||||
int optparse_long(struct optparse *options,
|
||||
const struct optparse_long *longopts,
|
||||
int *longindex);
|
||||
|
||||
/**
|
||||
* Used for stepping over non-option arguments.
|
||||
* @return the next non-option argument, or NULL for no more arguments
|
||||
*
|
||||
* Argument parsing can continue with optparse() after using this
|
||||
* function. That would be used to parse the options for the
|
||||
* subcommand returned by optparse_arg(). This function allows you to
|
||||
* ignore the value of optind.
|
||||
*/
|
||||
OPTPARSE_API
|
||||
char *optparse_arg(struct optparse *options);
|
||||
|
||||
/* Implementation */
|
||||
#ifdef OPTPARSE_IMPLEMENTATION
|
||||
|
||||
#define OPTPARSE_MSG_INVALID "invalid option"
|
||||
#define OPTPARSE_MSG_MISSING "option requires an argument"
|
||||
#define OPTPARSE_MSG_TOOMANY "option takes no arguments"
|
||||
|
||||
static int
|
||||
optparse_error(struct optparse *options, const char *msg, const char *data)
|
||||
{
|
||||
unsigned p = 0;
|
||||
const char *sep = " -- '";
|
||||
while (*msg)
|
||||
options->errmsg[p++] = *msg++;
|
||||
while (*sep)
|
||||
options->errmsg[p++] = *sep++;
|
||||
while (p < sizeof(options->errmsg) - 2 && *data)
|
||||
options->errmsg[p++] = *data++;
|
||||
options->errmsg[p++] = '\'';
|
||||
options->errmsg[p++] = '\0';
|
||||
return '?';
|
||||
}
|
||||
|
||||
OPTPARSE_API
|
||||
void
|
||||
optparse_init(struct optparse *options, char **argv)
|
||||
{
|
||||
options->argv = argv;
|
||||
options->permute = 1;
|
||||
options->optind = 1;
|
||||
options->subopt = 0;
|
||||
options->optarg = 0;
|
||||
options->errmsg[0] = '\0';
|
||||
}
|
||||
|
||||
static int
|
||||
optparse_is_dashdash(const char *arg)
|
||||
{
|
||||
return arg != 0 && arg[0] == '-' && arg[1] == '-' && arg[2] == '\0';
|
||||
}
|
||||
|
||||
static int
|
||||
optparse_is_shortopt(const char *arg)
|
||||
{
|
||||
return arg != 0 && arg[0] == '-' && arg[1] != '-' && arg[1] != '\0';
|
||||
}
|
||||
|
||||
static int
|
||||
optparse_is_longopt(const char *arg)
|
||||
{
|
||||
return arg != 0 && arg[0] == '-' && arg[1] == '-' && arg[2] != '\0';
|
||||
}
|
||||
|
||||
static void
|
||||
optparse_permute(struct optparse *options, int index)
|
||||
{
|
||||
char *nonoption = options->argv[index];
|
||||
int i;
|
||||
for (i = index; i < options->optind - 1; i++)
|
||||
options->argv[i] = options->argv[i + 1];
|
||||
options->argv[options->optind - 1] = nonoption;
|
||||
}
|
||||
|
||||
static int
|
||||
optparse_argtype(const char *optstring, char c)
|
||||
{
|
||||
int count = OPTPARSE_NONE;
|
||||
if (c == ':')
|
||||
return -1;
|
||||
for (; *optstring && c != *optstring; optstring++);
|
||||
if (!*optstring)
|
||||
return -1;
|
||||
if (optstring[1] == ':')
|
||||
count += optstring[2] == ':' ? 2 : 1;
|
||||
return count;
|
||||
}
|
||||
|
||||
OPTPARSE_API
|
||||
int
|
||||
optparse(struct optparse *options, const char *optstring)
|
||||
{
|
||||
int type;
|
||||
char *next;
|
||||
char *option = options->argv[options->optind];
|
||||
options->errmsg[0] = '\0';
|
||||
options->optopt = 0;
|
||||
options->optarg = 0;
|
||||
if (option == 0) {
|
||||
return -1;
|
||||
} else if (optparse_is_dashdash(option)) {
|
||||
options->optind++; /* consume "--" */
|
||||
return -1;
|
||||
} else if (!optparse_is_shortopt(option)) {
|
||||
if (options->permute) {
|
||||
int index = options->optind++;
|
||||
int r = optparse(options, optstring);
|
||||
optparse_permute(options, index);
|
||||
options->optind--;
|
||||
return r;
|
||||
} else {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
option += options->subopt + 1;
|
||||
options->optopt = option[0];
|
||||
type = optparse_argtype(optstring, option[0]);
|
||||
next = options->argv[options->optind + 1];
|
||||
switch (type) {
|
||||
case -1: {
|
||||
char str[2] = {0, 0};
|
||||
str[0] = option[0];
|
||||
options->optind++;
|
||||
return optparse_error(options, OPTPARSE_MSG_INVALID, str);
|
||||
}
|
||||
case OPTPARSE_NONE:
|
||||
if (option[1]) {
|
||||
options->subopt++;
|
||||
} else {
|
||||
options->subopt = 0;
|
||||
options->optind++;
|
||||
}
|
||||
return option[0];
|
||||
case OPTPARSE_REQUIRED:
|
||||
options->subopt = 0;
|
||||
options->optind++;
|
||||
if (option[1]) {
|
||||
options->optarg = option + 1;
|
||||
} else if (next != 0) {
|
||||
options->optarg = next;
|
||||
options->optind++;
|
||||
} else {
|
||||
char str[2] = {0, 0};
|
||||
str[0] = option[0];
|
||||
options->optarg = 0;
|
||||
return optparse_error(options, OPTPARSE_MSG_MISSING, str);
|
||||
}
|
||||
return option[0];
|
||||
case OPTPARSE_OPTIONAL:
|
||||
options->subopt = 0;
|
||||
options->optind++;
|
||||
if (option[1])
|
||||
options->optarg = option + 1;
|
||||
else
|
||||
options->optarg = 0;
|
||||
return option[0];
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
OPTPARSE_API
|
||||
char *
|
||||
optparse_arg(struct optparse *options)
|
||||
{
|
||||
char *option = options->argv[options->optind];
|
||||
options->subopt = 0;
|
||||
if (option != 0)
|
||||
options->optind++;
|
||||
return option;
|
||||
}
|
||||
|
||||
static int
|
||||
optparse_longopts_end(const struct optparse_long *longopts, int i)
|
||||
{
|
||||
return !longopts[i].longname && !longopts[i].shortname;
|
||||
}
|
||||
|
||||
static void
|
||||
optparse_from_long(const struct optparse_long *longopts, char *optstring)
|
||||
{
|
||||
char *p = optstring;
|
||||
int i;
|
||||
for (i = 0; !optparse_longopts_end(longopts, i); i++) {
|
||||
if (longopts[i].shortname) {
|
||||
int a;
|
||||
*p++ = longopts[i].shortname;
|
||||
for (a = 0; a < (int)longopts[i].argtype; a++)
|
||||
*p++ = ':';
|
||||
}
|
||||
}
|
||||
*p = '\0';
|
||||
}
|
||||
|
||||
/* Unlike strcmp(), handles options containing "=". */
|
||||
static int
|
||||
optparse_longopts_match(const char *longname, const char *option)
|
||||
{
|
||||
const char *a = option, *n = longname;
|
||||
if (longname == 0)
|
||||
return 0;
|
||||
for (; *a && *n && *a != '='; a++, n++)
|
||||
if (*a != *n)
|
||||
return 0;
|
||||
return *n == '\0' && (*a == '\0' || *a == '=');
|
||||
}
|
||||
|
||||
/* Return the part after "=", or NULL. */
|
||||
static char *
|
||||
optparse_longopts_arg(char *option)
|
||||
{
|
||||
for (; *option && *option != '='; option++);
|
||||
if (*option == '=')
|
||||
return option + 1;
|
||||
else
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
optparse_long_fallback(struct optparse *options,
|
||||
const struct optparse_long *longopts,
|
||||
int *longindex)
|
||||
{
|
||||
int result;
|
||||
char optstring[96 * 3 + 1]; /* 96 ASCII printable characters */
|
||||
optparse_from_long(longopts, optstring);
|
||||
result = optparse(options, optstring);
|
||||
if (longindex != 0) {
|
||||
*longindex = -1;
|
||||
if (result != -1) {
|
||||
int i;
|
||||
for (i = 0; !optparse_longopts_end(longopts, i); i++)
|
||||
if (longopts[i].shortname == options->optopt)
|
||||
*longindex = i;
|
||||
}
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
OPTPARSE_API
|
||||
int
|
||||
optparse_long(struct optparse *options,
|
||||
const struct optparse_long *longopts,
|
||||
int *longindex)
|
||||
{
|
||||
int i;
|
||||
char *option = options->argv[options->optind];
|
||||
if (option == 0) {
|
||||
return -1;
|
||||
} else if (optparse_is_dashdash(option)) {
|
||||
options->optind++; /* consume "--" */
|
||||
return -1;
|
||||
} else if (optparse_is_shortopt(option)) {
|
||||
return optparse_long_fallback(options, longopts, longindex);
|
||||
} else if (!optparse_is_longopt(option)) {
|
||||
if (options->permute) {
|
||||
int index = options->optind++;
|
||||
int r = optparse_long(options, longopts, longindex);
|
||||
optparse_permute(options, index);
|
||||
options->optind--;
|
||||
return r;
|
||||
} else {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
/* Parse as long option. */
|
||||
options->errmsg[0] = '\0';
|
||||
options->optopt = 0;
|
||||
options->optarg = 0;
|
||||
option += 2; /* skip "--" */
|
||||
options->optind++;
|
||||
for (i = 0; !optparse_longopts_end(longopts, i); i++) {
|
||||
const char *name = longopts[i].longname;
|
||||
if (optparse_longopts_match(name, option)) {
|
||||
char *arg;
|
||||
if (longindex)
|
||||
*longindex = i;
|
||||
options->optopt = longopts[i].shortname;
|
||||
arg = optparse_longopts_arg(option);
|
||||
if (longopts[i].argtype == OPTPARSE_NONE && arg != 0) {
|
||||
return optparse_error(options, OPTPARSE_MSG_TOOMANY, name);
|
||||
} if (arg != 0) {
|
||||
options->optarg = arg;
|
||||
} else if (longopts[i].argtype == OPTPARSE_REQUIRED) {
|
||||
options->optarg = options->argv[options->optind++];
|
||||
if (options->optarg == 0)
|
||||
return optparse_error(options, OPTPARSE_MSG_MISSING, name);
|
||||
}
|
||||
return options->optopt;
|
||||
}
|
||||
}
|
||||
return optparse_error(options, OPTPARSE_MSG_INVALID, option);
|
||||
}
|
||||
|
||||
#endif /* OPTPARSE_IMPLEMENTATION */
|
||||
#endif /* OPTPARSE_H */
|
||||
Loading…
Reference in New Issue