48 lines
1.6 KiB
C++
48 lines
1.6 KiB
C++
/*
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U2FDevice - A program to allow Raspberry Pi Zeros to act as U2F tokens
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Copyright (C) 2018 Michael Kuc
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include "Signature.hpp"
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#include <iostream>
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using namespace std;
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//Ripped from https://github.com/pratikd650/Teensy_U2F/blob/master/Teensy_U2F.cpp
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void appendSignatureAsDER(vector<uint8_t> &response, const array<uint8_t, 64> &signature)
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{
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response.push_back(0x30); // Start of ASN.1 SEQUENCE
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response.push_back(68); //total length from (2 * (32 + 2)) to (2 * (33 + 2))
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size_t countByte = response.size() - 1;
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// Loop twice - for R and S
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for(unsigned int i = 0; i < 2; i++)
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{
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unsigned int sigOffs = i * 32;
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auto offset = signature.begin() + sigOffs;
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response.push_back(0x02); //header: integer
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response.push_back(32); //32 byte
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if (signature[sigOffs] > 0x7f)
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{
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// Integer needs to be represented in 2's completement notion
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response.back()++;
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response.push_back(0); // add leading 0, to indicate it is a positive number
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response[countByte]++;
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}
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copy(offset, offset + 32, back_inserter(response)); //R or S value
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}
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}
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