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finished SSLCLient implementation, in process of fixing syntax errors and need to rigorously document

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This commit is contained in:
Noah Laptop 2019-02-26 12:17:25 -08:00
parent f4ea538dab
commit 0546070cbd
2 changed files with 226 additions and 59 deletions
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242
src/SSLClient.cpp
View file

@ -21,17 +21,28 @@
#include "SSLClient.h" #include "SSLClient.h"
/** see SSLClient.h */ /** see SSLClient.h */
SSLClient::SSLClient(const C &client, const br_x509_trust_anchor *trust_anchors, const size_t trust_anchors_num, const bool debug) { template<class C>
SSLClient<C>::SSLClient(const C &client, const br_x509_trust_anchor *trust_anchors, const size_t trust_anchors_num, const bool debug)
: m_client(client)
, m_trust_anchors(trust_anchors)
, m_trust_anchors_num(trust_anchors_num)
, m_debug(debug)
, m_write_idx(0) {
// zero the iobuf just in case it's still garbage
memset(m_iobuf, 0, sizeof m_iobuf);
// initlalize the various bearssl libraries so they're ready to go when we connect // initlalize the various bearssl libraries so they're ready to go when we connect
br_client_init_TLS12_only(&m_sslctx, &m_x509ctx, m_trust_anchors, m_trust_anchors_num); br_client_init_TLS12_only(&m_sslctx, &m_x509ctx, m_trust_anchors, m_trust_anchors_num);
// check if the buffer size is half or full duplex // check if the buffer size is half or full duplex
constexpr auto duplex = sizeof iobuf <= BR_SSL_BUFSIZE_MONO ? 0 : 1; constexpr auto duplex = sizeof iobuf <= BR_SSL_BUFSIZE_MONO ? 0 : 1;
br_ssl_engine_set_buffer(&m_sslctx, m_iobuf, sizeof m_iobuf, duplex); br_ssl_engine_set_buffer(&m_sslctx, m_iobuf, sizeof m_iobuf, duplex);
br_sslio_init(&m_ioctx, &m_sslctx.eng, m_readraw, NULL, m_writeraw, NULL);
} }
/* see SSLClient.h */ /* see SSLClient.h */
virtual int SSLClient::connect(IPAddress ip, uint16_t port) { template<class C>
int SSLClient<C>::connect(IPAddress ip, uint16_t port) {
// reset indexs for saftey
m_write_idx = 0;
// Warning for security // Warning for security
m_print("Warning! Using a raw IP Address for an SSL connection bypasses some important verification steps\nYou should use a domain name (www.google.com) whenever possible."); m_print("Warning! Using a raw IP Address for an SSL connection bypasses some important verification steps\nYou should use a domain name (www.google.com) whenever possible.");
// first we need our hidden client member to negotiate the socket for us, // first we need our hidden client member to negotiate the socket for us,
@ -46,7 +57,7 @@ virtual int SSLClient::connect(IPAddress ip, uint16_t port) {
// initlalize the SSL socket over the network // initlalize the SSL socket over the network
// normally this would happen in br_sslio_write, but I think it makes // normally this would happen in br_sslio_write, but I think it makes
// a little more structural sense to put it here // a little more structural sense to put it here
if (m_run_until(ctx, BR_SSL_SENDAPP) < 0) { if (m_run_until(BR_SSL_SENDAPP) < 0) {
m_print("Failed to initlalize the SSL layer"); m_print("Failed to initlalize the SSL layer");
setWriteError(SSL_BR_CONNECT_FAIL); setWriteError(SSL_BR_CONNECT_FAIL);
return 0; return 0;
@ -58,7 +69,10 @@ virtual int SSLClient::connect(IPAddress ip, uint16_t port) {
} }
/* see SSLClient.h */ /* see SSLClient.h */
virtual int SSLClient::connect(const char *host, uint16_t port) { template<class C>
int SSLClient<C>::connect(const char *host, uint16_t port) {
// reset indexs for saftey
m_write_idx = 0;
// first we need our hidden client member to negotiate the socket for us, // first we need our hidden client member to negotiate the socket for us,
// since most times socket functionality is implemented in hardeware. // since most times socket functionality is implemented in hardeware.
if (!this->m_client.connect(host, port)) { if (!this->m_client.connect(host, port)) {
@ -82,38 +96,62 @@ virtual int SSLClient::connect(const char *host, uint16_t port) {
return 1; return 1;
} }
/** see SSLClient.h TODO: fix */ /** see SSLClient.h */
virtual size_t SSLClient::write(const uint8_t *buf, size_t size) { template<class C>
size_t SSLClient<C>::write(const uint8_t *buf, size_t size) {
// check if the socket is still open and such // check if the socket is still open and such
if(!m_client.connected()) { if(!m_client.connected()) {
m_print("Client is not connected! Perhaps something has happened?"); m_print("Client is not connected! Perhaps something has happened?");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_CLIENT_CONNECT_FAIL); setWriteError(SSL_CLIENT_CONNECT_FAIL);
return 0; return 0;
} }
// write to the ssl socket using bearssl, and error check // add to the bearssl io buffer, simply appending whatever we want to write
const auto status = br_sslio_write_all(&m_ioctx, buf, size); size_t alen;
if (status != size) { unsigned char *br_buf = br_ssl_engine_sendapp_buf(m_sslctx->engine, &alen);
if (status < 0) { size_t cur_idx = 0;
m_print("Encountered a write error:"); // while there are still elements to write
if (m_client.getWriteError()) { while (cur_idx < size) {
m_print("m_client write error"); // run until the ssl socket is ready to write, unless we've already written
setWriteError(SSL_CLIENT_WRTIE_ERROR); // to the buffer in which we conclude it's already safe to write
} if(m_write_idx == 0) {
else { if (m_run_until(BR_SSL_SENDAPP) < 0) {
m_print("bearssl write error: "); m_print("Error: could not run until sendapp");
m_print(err = br_ssl_engine_last_error(&m_sslctx.eng));
setWriteError(SSL_BR_WRITE_ERROR); setWriteError(SSL_BR_WRITE_ERROR);
}
return 0; return 0;
} }
m_print("Warn: Wrote less than status! Something might be wrong"); // reset the buffer pointer
br_ssl_engine_sendapp_buf(m_sslctx->engine, &alen);
} }
return status; // sanity check
if(br_buf == NULL || alen == 0) {
m_print("Error: recieved null buffer or zero alen in write");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_BR_WRITE_ERROR);
return 0;
}
// if we're about to fill the buffer, we need to send the data and then wait
// for another oppurtinity to send
const size_t cpamount = m_write_idx + (size - cur_idx) > alen ? alen : size - cur_idx;
memcpy(br_buf + m_write_idx, buf + cur_idx, cpamount);
// if we filled the buffer, reset m_write_idx
if (cpamount == alen) m_write_idx = 0;
// else increment
else m_write_idx += cpamount;
// increment the buffer pointer
cur_size += cpamount;
}
// works oky
return size;
} }
virtual int SSLClient::available() { /** see SSLClient.h */
template<class C>
int SSLClient<C>::available() {
if (!m_client.connected()) { if (!m_client.connected()) {
m_print("Cannot check available of disconnected client!"); m_print("Warn: Cannot check available of disconnected client");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_CLIENT_CONNECT_FAIL);
return 0; return 0;
} }
// run the SSL engine until we are waiting for either user input or a server response // run the SSL engine until we are waiting for either user input or a server response
@ -121,14 +159,14 @@ virtual int SSLClient::available() {
if(state & BR_SSL_RECVAPP) { if(state & BR_SSL_RECVAPP) {
// return how many received bytes we have // return how many received bytes we have
size_t alen; size_t alen;
br_ssl_engine_recvapp_buf(ctx->engine, &alen); br_ssl_engine_recvapp_buf(m_sslctx->engine, &alen);
return (int)alen; return (int)(alen);
} }
else if (state == BR_SSL_CLOSED) m_print("Tried to check available when engine is closed!"); else if (state == BR_SSL_CLOSED) m_print("Error: Tried to check available when engine is closed");
// flush the buffer if it's stuck in the SENDAPP state // flush the buffer if it's stuck in the SENDAPP state
else if (state & BR_SSL_SENDAPP) br_ssl_engine_flush(m_sslctx->engine, 0); else if (state & BR_SSL_SENDAPP) br_ssl_engine_flush(m_sslctx->engine, 0);
else if (state == 0) { else if (state == 0) {
m_print("SSL engine failed: "); m_print("Error: SSL engine failed: ");
m_print(br_ssl_engine_last_error(&m_sslctx)); m_print(br_ssl_engine_last_error(&m_sslctx));
setWriteError(SSL_BR_WRITE_ERROR); setWriteError(SSL_BR_WRITE_ERROR);
} }
@ -136,7 +174,71 @@ virtual int SSLClient::available() {
return 0; return 0;
} }
int SSLClient::m_run_until(const unsigned target) { /** see SSLClient.h */
template<class C>
int SSLClient<C>::read(uint8_t *buf, size_t size) {
// check that the engine is ready to read
else if (available()) {
// read the buffer, send the ack, and return the bytes read
size_t alen;
unsigned char* br_buf = br_ssl_engine_recvapp_buf(m_sslctx->engine, &alen);
const size_t read_amount = size > alen ? alen : size;
memcpy(buf, br_buf, read_amount);
// tell engine we read that many bytes
br_ssl_engine_sendapp_ack(m_sslctx->engine, read_amount);
// tell the user we read that many bytes
return read_amount;
}
return -1;
}
/** see SSLClient.h */
template<class C>
int SSLClient<C>::peek() {
// check that the engine is ready to read
if (available()) {
// read the buffer, send the ack, and return the bytes read
size_t alen;
uint8_t read_num;
read_num = br_ssl_engine_recvapp_buf(m_sslctx->engine, &alen)[0];
// tell the user we read that many bytes
return (int)read_num;
}
return -1;
}
/** see SSLClient.h */
template<class C>
void SSLClient<C>::flush() {
// trigger a flush, incase there's any leftover data
br_ssl_engine_flush(m_sslctx->engine, 0);
// run until application data is ready for pickup
if(m_run_until(BR_SSL_RECVAPP) < 0) m_print("Error: could not flush write buffer!");
}
/** see SSLClient.h */
template<class C>
void SSLClient<C>::stop() {
// tell the SSL connection to gracefully close
br_ssl_engine_close(m_sslctx->engine);
while (br_ssl_engine_current_state(m_sslctx->engine) != BR_SSL_CLOSED) {
/*
* Discard any incoming application data.
*/
size_t len;
m_run_until(BR_SSL_RECVAPP);
if (br_ssl_engine_recvapp_buf(m_sslctx->engine, &len) != NULL) {
br_ssl_engine_recvapp_ack(m_sslctx->engine, len);
}
}
// close the ethernet socket
m_client.stop();
}
/** see SSLClient.h */
template<class C>
int SSLClient<C>::m_run_until(const unsigned target) {
for (;;) { for (;;) {
unsigned state = m_update_engine(); unsigned state = m_update_engine();
/* /*
@ -150,9 +252,24 @@ int SSLClient::m_run_until(const unsigned target) {
* and that's not possible until the application data is * and that's not possible until the application data is
* read. This may happen if using a shared in/out buffer, * read. This may happen if using a shared in/out buffer,
* and the underlying protocol is not strictly half-duplex. * and the underlying protocol is not strictly half-duplex.
* This is unrecoverable here, so we report an error. * Normally this would be unrecoverable, however we can attempt
* to remedy the problem by telling the engine to discard
* the data.
*/ */
if (state & BR_SSL_RECVAPP && target & BR_SSL_SENDAPP) return -1; if (state & BR_SSL_RECVAPP && target & BR_SSL_SENDAPP) {
size_t len;
if (br_ssl_engine_recvapp_buf(m_sslctx->engine, &len) != NULL) {
m_write_idx = 0;
m_print("Warn: discarded unread data to favor a write operation");
br_ssl_engine_recvapp_ack(m_sslctx->engine, len);
}
else {
m_print("Error: ssl engine state is RECVAPP, however the buffer was null!");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_BR_WRITE_ERROR);
return -1;
}
}
/* /*
* We can reach that point if the target RECVAPP, and * We can reach that point if the target RECVAPP, and
@ -165,6 +282,8 @@ int SSLClient::m_run_until(const unsigned target) {
} }
} }
/** see SSLClient.h */
template<class C>
unsigned SSLClient::m_update_engine() { unsigned SSLClient::m_update_engine() {
for(;;) { for(;;) {
// get the state // get the state
@ -179,9 +298,10 @@ unsigned SSLClient::m_update_engine() {
size_t len; size_t len;
int wlen; int wlen;
buf = br_ssl_engine_sendrec_buf(ctx->engine, &len); buf = br_ssl_engine_sendrec_buf(m_sslctx->engine, &len);
wlen = m_client.write(buf, len); wlen = m_client.write(buf, len);
if (wlen < 0) { if (wlen < 0) {
m_print("Error writing to m_client");
/* /*
* If we received a close_notify and we * If we received a close_notify and we
* still send something, then we have our * still send something, then we have our
@ -189,19 +309,64 @@ unsigned SSLClient::m_update_engine() {
* the peer is allowed by RFC 5246 not to * the peer is allowed by RFC 5246 not to
* wait for it. * wait for it.
*/ */
if (!ctx->engine->shutdown_recv) { if (!m_sslctx->engine->shutdown_recv) {
br_ssl_engine_fail( br_ssl_engine_fail(
ctx->engine, BR_ERR_IO); m_sslctx->engine, BR_ERR_IO);
} }
setWriteError(SSL_BR_WRITE_ERROR); setWriteError(SSL_BR_WRITE_ERROR);
return 0; return 0;
} }
if (wlen > 0) { if (wlen > 0) {
br_ssl_engine_sendrec_ack(ctx->engine, wlen); br_ssl_engine_sendrec_ack(m_sslctx->engine, wlen);
} }
continue; continue;
} }
/*
* If the client has specified there is client data to send, and
* the engine is ready to handle it, send it along.
*/
if (m_write_idx > 0) {
// if we've reached the point where BR_SSL_SENDAPP is off but
// data has been written to the io buffer, something is wrong
if (!(state & BR_SSL_SENDAPP)) {
m_print("Error m_write_idx > 0 but the ssl engine is not ready for data");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_BR_WRITE_ERROR);
return 0;
}
// else time to send the application data
else if (state & BR_SSL_SENDAPP) {
size_t alen;
unsigned char *buf = br_ssl_engine_sendapp_buf(m_sslctx->engine, &alen);
// engine check
if (alen == 0 || buf == NULL) {
m_print("Error: engine set write flag but returned null buffer");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_BR_WRITE_ERROR);
return 0;
}
// sanity check
if (alen < m_write_idx) {
m_print("Error: alen is less than m_write_idx");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_INTERNAL_ERROR);
return 0;
}
// all good? lets send the data
// presumably the SSLClient::write function has already added
// data to *buf, so now we tell bearssl it's time for the
// encryption step.
// this will encrypt the data and presumably spit it out
// for BR_SSL_SENDREC to send over ethernet.
br_ssl_engine_sendapp_ack(m_sslctx->engine, m_write_idx);
// reset the iobuffer index
m_write_idx = 0;
// loop again!
continue;
}
}
/* /*
* If there is some record data to recieve, check if we've * If there is some record data to recieve, check if we've
* recieved it so far. If we have, then we can update the state. * recieved it so far. If we have, then we can update the state.
@ -209,18 +374,19 @@ unsigned SSLClient::m_update_engine() {
*/ */
if (state & BR_SSL_RECVREC) { if (state & BR_SSL_RECVREC) {
size_t len; size_t len;
unsigned char * buf = br_ssl_engine_recvrec_buf(ctx->engine, &len); unsigned char * buf = br_ssl_engine_recvrec_buf(m_sslctx->engine, &len);
// do we have the record you're looking for? // do we have the record you're looking for?
if (m_client.available() >= len) { if (m_client.available() >= len) {
// I suppose so! // I suppose so!
int rlen = m_client.readBytes((char *)buf, len); int rlen = m_client.readBytes((char *)buf, len);
if (rlen < 0) { if (rlen < 0) {
br_ssl_engine_fail(ctx->engine, BR_ERR_IO); m_print("Error reading bytes from m_client");
br_ssl_engine_fail(m_sslctx->engine, BR_ERR_IO);
setWriteError(SSL_BR_WRITE_ERROR); setWriteError(SSL_BR_WRITE_ERROR);
return 0; return 0;
} }
if (rlen > 0) { if (rlen > 0) {
br_ssl_engine_recvrec_ack(ctx->engine, rlen); br_ssl_engine_recvrec_ack(m_sslctx->engine, rlen);
} }
continue; continue;
} }

43
src/SSLClient.h
View file

@ -35,7 +35,7 @@
#include "bearssl.h" #include "bearssl.h"
#include "Client.h" #include "Client.h"
#ifdef SSLClient_H_ #ifndef SSLClient_H_
#define SSLClient_H_ #define SSLClient_H_
template <class C> template <class C>
@ -46,20 +46,23 @@ class SSLClient : public Client {
* actually present on class C. It does this by first checking that the * actually present on class C. It does this by first checking that the
* class inherits from Client, and then that it contains a status() function. * class inherits from Client, and then that it contains a status() function.
*/ */
static_assert(std::is_base_of(Client, C)::value, "C must be a Client Class!"); //static_assert(std::is_base_of(Client, C)::value, "C must be a Client Class!");
static_assert(std::is_function(decltype(C::status))::value, "C must have a status() function!"); //static_assert(std::is_function(decltype(C::status))::value, "C must have a status() function!");
/** error enums /** error enums
* Static constants defining the possible errors encountered * Static constants defining the possible errors encountered
* Read from getWriteError(); * Read from getWriteError();
*/ */
/*
enum Error { enum Error {
SSL_OK = 0, SSL_OK = 0,
SSL_CLIENT_CONNECT_FAIL, SSL_CLIENT_CONNECT_FAIL,
SSL_BR_CONNECT_FAIL, SSL_BR_CONNECT_FAIL,
SSL_CLIENT_WRTIE_ERROR, SSL_CLIENT_WRTIE_ERROR,
SSL_BR_WRITE_ERROR, SSL_BR_WRITE_ERROR,
SSL_INTERNAL_ERROR
}; };
*/
public: public:
/** /**
@ -77,12 +80,7 @@ public:
* @param trust_anchors_num The number of trust anchors stored * @param trust_anchors_num The number of trust anchors stored
* @param debug whether to enable or disable debug logging, must be constexpr * @param debug whether to enable or disable debug logging, must be constexpr
*/ */
SSLClient(const C client, const br_x509_trust_anchor *trust_anchors, const size_t trust_anchors_num, const bool debug = true) explicit SSLClient(const C client, const br_x509_trust_anchor *trust_anchors, const size_t trust_anchors_num, const bool debug = true);
: m_client(client)
, m_trust_anchors(trust_anchors)
, m_trust_anchors_num(trust_anchors_num)
, m_debug(debug);
/** Dtor is implicit since unique_ptr handles it fine */ /** Dtor is implicit since unique_ptr handles it fine */
/** /**
@ -127,7 +125,7 @@ public:
* @error SSL_CLIENT_CONNECT_FAIL The client object could not connect to the host or port * @error SSL_CLIENT_CONNECT_FAIL The client object could not connect to the host or port
* @error SSL_BR_CONNECT_FAIL BearSSL could not initialize the SSL connection. * @error SSL_BR_CONNECT_FAIL BearSSL could not initialize the SSL connection.
*/ */
virtual int connect(IPAddress ip, uint16_t port = 443); virtual int connect(IPAddress ip, uint16_t port);
/** /**
* @brief Connect over SSL using connect(ip, port), but use a DNS lookup to * @brief Connect over SSL using connect(ip, port), but use a DNS lookup to
* get the IP Address first. * get the IP Address first.
@ -151,11 +149,11 @@ public:
* @error SSL_CLIENT_CONNECT_FAIL The client object could not connect to the host or port * @error SSL_CLIENT_CONNECT_FAIL The client object could not connect to the host or port
* @error SSL_BR_CONNECT_FAIL BearSSL could not initialize the SSL connection. * @error SSL_BR_CONNECT_FAIL BearSSL could not initialize the SSL connection.
*/ */
virtual int connect(const char *host, uint16_t port = 443); virtual int connect(const char *host, uint16_t port);
virtual size_t write(uint8_t b) { return write(&b, 1); } virtual size_t write(uint8_t b) { return write(&b, 1); }
virtual size_t write(const uint8_t *buf, size_t size); virtual size_t write(const uint8_t *buf, size_t size);
virtual int available(); virtual int available();
virtual int read(); virtual int read() { int peeked = peek(); if(peek != -1) br_ssl_engine_recvapp_ack(m_sslctx->engine, 1); return peek; }
virtual int read(uint8_t *buf, size_t size); virtual int read(uint8_t *buf, size_t size);
virtual int peek(); virtual int peek();
virtual void flush(); virtual void flush();
@ -167,8 +165,8 @@ public:
private: private:
/** @brief debugging print function, only prints if m_debug is true */ /** @brief debugging print function, only prints if m_debug is true */
template<type T> template<typename T>
constexpr void m_print(const T str) { constexpr void m_print(const T str) const {
if (m_debug) { if (m_debug) {
Serial.print("SSLClient: "); Serial.print("SSLClient: ");
Serial.println(str); Serial.println(str);
@ -177,15 +175,15 @@ private:
/** run the bearssl engine until a certain state */ /** run the bearssl engine until a certain state */
int m_run_until(const unsigned target); int m_run_until(const unsigned target);
/** proxy for availble that returns the state */ /** proxy for availble that returns the state */
int m_update_engine(); unsigned m_update_engine();
// create a copy of the client // create a copy of the client
const C m_client; C m_client;
// store pointers to the trust anchors // store pointers to the trust anchors
// should not be computed at runtime // should not be computed at runtime
constexpr br_x509_trust_anchor *m_trust_anchors; const br_x509_trust_anchor *m_trust_anchors;
constexpr size_t m_trust_anchors_num; const size_t m_trust_anchors_num;
// store whether to enable debug logging // store whether to enable debug logging
constexpr bool m_debug; const bool m_debug;
// store the context values required for SSL // store the context values required for SSL
br_ssl_client_context m_sslctx; br_ssl_client_context m_sslctx;
br_x509_minimal_context m_x509ctx; br_x509_minimal_context m_x509ctx;
@ -194,8 +192,11 @@ private:
// or shrink to below BR_SSL_BUFSIZE_MONO, and bearSSL will adapt automatically // or shrink to below BR_SSL_BUFSIZE_MONO, and bearSSL will adapt automatically
// simply edit this value to change the buffer size to the desired value // simply edit this value to change the buffer size to the desired value
unsigned char m_iobuf[BR_SSL_BUFSIZE_MONO]; unsigned char m_iobuf[BR_SSL_BUFSIZE_MONO];
static_assert(sizeof m_iobuf <= BR_SSL_BUFSIZE_BIDI); // static_assert(sizeof m_iobuf <= BR_SSL_BUFSIZE_BIDI);
br_sslio_context m_ioctx; // store the index of where we are writing in the buffer
// so we can send our records all at once to prevent
// weird timing issues
size_t m_write_idx;
}; };
#endif /** SSLClient_H_ */ #endif /** SSLClient_H_ */