Fix Sec-WebSocket-Key to contain valid Base64. (#389)

The generated header only "looked like" Base64, but if the other side
actually tried to decode it as such, it could fail. This change fixes
that to always generate a valid Base64 value.

The Base64 code is copied from
https://gist.github.com/tomykaira/f0fd86b6c73063283afe550bc5d77594.
This commit is contained in:
Robin Sommer 2022-04-29 09:05:06 +02:00 committed by GitHub
parent 2f560ff4c0
commit edb6ded99f
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 128 additions and 8 deletions

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@ -66,6 +66,7 @@ set( IXWEBSOCKET_SOURCES
)
set( IXWEBSOCKET_HEADERS
ixwebsocket/IXBase64.h
ixwebsocket/IXBench.h
ixwebsocket/IXCancellationRequest.h
ixwebsocket/IXConnectionState.h

124
ixwebsocket/IXBase64.h Normal file
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@ -0,0 +1,124 @@
#ifndef _MACARON_BASE64_H_
#define _MACARON_BASE64_H_
/**
* The MIT License (MIT)
* Copyright (c) 2016 tomykaira
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <string>
namespace macaron {
class Base64 {
public:
static std::string Encode(const std::string data) {
static constexpr char sEncodingTable[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/'
};
size_t in_len = data.size();
size_t out_len = 4 * ((in_len + 2) / 3);
std::string ret(out_len, '\0');
size_t i;
char *p = const_cast<char*>(ret.c_str());
for (i = 0; i < in_len - 2; i += 3) {
*p++ = sEncodingTable[(data[i] >> 2) & 0x3F];
*p++ = sEncodingTable[((data[i] & 0x3) << 4) | ((int) (data[i + 1] & 0xF0) >> 4)];
*p++ = sEncodingTable[((data[i + 1] & 0xF) << 2) | ((int) (data[i + 2] & 0xC0) >> 6)];
*p++ = sEncodingTable[data[i + 2] & 0x3F];
}
if (i < in_len) {
*p++ = sEncodingTable[(data[i] >> 2) & 0x3F];
if (i == (in_len - 1)) {
*p++ = sEncodingTable[((data[i] & 0x3) << 4)];
*p++ = '=';
}
else {
*p++ = sEncodingTable[((data[i] & 0x3) << 4) | ((int) (data[i + 1] & 0xF0) >> 4)];
*p++ = sEncodingTable[((data[i + 1] & 0xF) << 2)];
}
*p++ = '=';
}
return ret;
}
static std::string Decode(const std::string& input, std::string& out) {
static constexpr unsigned char kDecodingTable[] = {
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
64, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
};
size_t in_len = input.size();
if (in_len % 4 != 0) return "Input data size is not a multiple of 4";
size_t out_len = in_len / 4 * 3;
if (input[in_len - 1] == '=') out_len--;
if (input[in_len - 2] == '=') out_len--;
out.resize(out_len);
for (size_t i = 0, j = 0; i < in_len;) {
uint32_t a = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
uint32_t b = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
uint32_t c = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
uint32_t d = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
uint32_t triple = (a << 3 * 6) + (b << 2 * 6) + (c << 1 * 6) + (d << 0 * 6);
if (j < out_len) out[j++] = (triple >> 2 * 8) & 0xFF;
if (j < out_len) out[j++] = (triple >> 1 * 8) & 0xFF;
if (j < out_len) out[j++] = (triple >> 0 * 8) & 0xFF;
}
return "";
}
};
}
#endif /* _MACARON_BASE64_H_ */

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@ -6,6 +6,7 @@
#include "IXWebSocketHandshake.h"
#include "IXBase64.h"
#include "IXHttp.h"
#include "IXSocketConnect.h"
#include "IXStrCaseCompare.h"
@ -17,7 +18,6 @@
#include <random>
#include <sstream>
namespace ix
{
WebSocketHandshake::WebSocketHandshake(
@ -106,15 +106,10 @@ namespace ix
return WebSocketInitResult(false, 0, ss.str());
}
//
// Generate a random 24 bytes string which looks like it is base64 encoded
// y3JJHMbDL1EzLkh9GBhXDw==
// 0cb3Vd9HkbpVVumoS3Noka==
// Generate a random 16 bytes string and base64 encode it.
//
// See https://stackoverflow.com/questions/18265128/what-is-sec-websocket-key-for
//
std::string secWebSocketKey = genRandomString(22);
secWebSocketKey += "==";
std::string secWebSocketKey = macaron::Base64::Encode(genRandomString(16));
std::stringstream ss;
ss << "GET " << path << " HTTP/1.1\r\n";