more tls in memory certs doc + bump file format

docs/CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 All changes to this project will be documented in this file.
 
+## [9.4.0] - 2020-04-24
+
+(ssl) Add support for supplying SSL CA from memory, for OpenSSL and MbedTLS backends
+
 ## [9.3.3] - 2020-04-17
 
 (ixbots) display sent/receive message, per seconds as accumulated

docs/design.md

@@ -38,8 +38,7 @@ The regression test is running after each commit on github actions for multiple
 
 ## Limitations
 
-* On Windows and Android certificate validation needs to be setup so that SocketTLSOptions.caFile point to a pem file, such as the one distributed by Firefox. Unless that setup is done connecting to a wss endpoint will display an error. On Windows with mbedtls the message will contain `error in handshake : X509 - Certificate verification failed, e.g. CRL, CA or signature check failed`.
-* There is no convenient way to embed a ca cert.
+* On some configuration (mostly Android) certificate validation needs to be setup so that SocketTLSOptions.caFile point to a pem file, such as the one distributed by Firefox. Unless that setup is done connecting to a wss endpoint will display an error. With mbedtls the message will contain `error in handshake : X509 - Certificate verification failed, e.g. CRL, CA or signature check failed`.
 * Automatic reconnection works at the TCP socket level, and will detect remote end disconnects. However, if the device/computer network become unreachable (by turning off wifi), it is quite hard to reliably and timely detect it at the socket level using `recv` and `send` error codes. [Here](https://stackoverflow.com/questions/14782143/linux-socket-how-to-detect-disconnected-network-in-a-client-program) is a good discussion on the subject. This behavior is consistent with other runtimes such as node.js. One way to detect a disconnected device with low level C code is to do a name resolution with DNS but this can be expensive. Mobile devices have good and reliable API to do that.
 * The server code is using select to detect incoming data, and creates one OS thread per connection. This is not as scalable as strategies using epoll or kqueue.
 

docs/usage.md

@@ -447,7 +447,7 @@ Additional TLS options can be configured by passing a `ix::SocketTLSOptions` ins
 webSocket.setTLSOptions({
     .certFile = "path/to/cert/file.pem",
     .keyFile = "path/to/key/file.pem",
-    .caFile = "path/to/trust/bundle/file.pem",
+    .caFile = "path/to/trust/bundle/file.pem", // as a file, or in memory buffer in PEM format
     .tls = true // required in server mode
 });
 ```
@@ -461,6 +461,7 @@ On a server, this is necessary for TLS support.
 Specifying `caFile` configures the trusted roots bundle file (in PEM format) that will be used to verify peer certificates.
  - The special value of `SYSTEM` (the default) indicates that the system-configured trust bundle should be used; this is generally what you want when connecting to any publicly exposed API/server.
  - The special value of `NONE` can be used to disable peer verification; this is only recommended to rule out certificate verification when testing connectivity.
+ - If the value contain the special value `-----BEGIN CERTIFICATE-----`, the value will be read from memory, and not from a file. This is convenient on platforms like Android where reading / writing to the file system can be challenging without proper permissions, or without knowing the location of a temp directory.
 
 For a client, specifying `caFile` can be used if connecting to a server that uses a self-signed cert, or when using a custom CA in an internal environment.
 

ixwebsocket/IXSocketMbedTLS.cpp

@@ -1,6 +1,6 @@
 /*
  *  IXSocketMbedTLS.cpp
- *  Author: Benjamin Sergeant
+ *  Author: Benjamin Sergeant, Max Weisel
  *  Copyright (c) 2019-2020 Machine Zone, Inc. All rights reserved.
  *
  *  Some code taken from

ixwebsocket/IXSocketOpenSSL.cpp

@@ -1,6 +1,6 @@
 /*
  *  IXSocketOpenSSL.cpp
- *  Author: Benjamin Sergeant, Matt DeBoer
+ *  Author: Benjamin Sergeant, Matt DeBoer, Max Weisel
  *  Copyright (c) 2017-2020 Machine Zone, Inc. All rights reserved.
  *
  *  Adapted from Satori SDK OpenSSL code.

ixwebsocket/IXSocketTLSOptions.cpp

@@ -15,6 +15,7 @@ namespace ix
     const char* kTLSCAFileUseSystemDefaults = "SYSTEM";
     const char* kTLSCAFileDisableVerify = "NONE";
     const char* kTLSCiphersUseDefault = "DEFAULT";
+    const char* kTLSInMemoryMarker = "-----BEGIN CERTIFICATE-----";
 
     bool SocketTLSOptions::isValid() const
     {
@@ -60,7 +61,7 @@ namespace ix
 
     bool SocketTLSOptions::isUsingInMemoryCAs() const
     {
-        return caFile.find("-----BEGIN CERTIFICATE-----") != std::string::npos;
+        return caFile.find(kTLSInMemoryMarker) != std::string::npos;
     }
 
     bool SocketTLSOptions::isPeerVerifyDisabled() const

ixwebsocket/IXWebSocketVersion.h

@@ -6,4 +6,4 @@
 
 #pragma once
 
-#define IX_WEBSOCKET_VERSION "9.3.3"
+#define IX_WEBSOCKET_VERSION "9.4.0"