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Moved SSLSession stuff to SSLClientImpl

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This commit is contained in:
Noah Laptop 2019-03-26 12:54:22 -07:00
parent 843d19bf6c
commit c5790a7012
3 changed files with 131 additions and 107 deletions
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116
src/SSLClient.h
View file

@ -99,14 +99,13 @@ public:
* @param debug whether to enable or disable debug logging, must be constexpr
*/
explicit SSLClient(const C& client, const br_x509_trust_anchor *trust_anchors, const size_t trust_anchors_num, const int analog_pin, const DebugLevel debug = SSL_WARN)
: SSLClientImpl(NULL, trust_anchors, trust_anchors_num, analog_pin, debug)
: SSLClientImpl(NULL, trust_anchors, trust_anchors_num, analog_pin, NULL, debug)
, m_client(client)
, m_sessions{SSLSession()}
, m_index(0)
{
// since we are copying the client in the ctor, we have to set
// the client pointer after the class is constructed
set_client(&m_client);
set_client(&m_client, m_sessions);
// set the timeout to a reasonable number (it can always be changes later)
// SSL Connections take a really long time so we don't want to time out a legitimate thing
setTimeout(10 * 1000);
@ -371,6 +370,38 @@ public:
//= Functions Not in the Client Interface
//========================================
/**
* @brief Get a sesssion reference corressponding to a host and IP, or a reference to a emptey session if none exist
*
* If no session corresponding to the host and ip exist, then this function will cycle through
* sessions in a rotating order. This allows the ssession cache to continuially store sessions,
* however it will also result in old sessions being cleared and returned. In general, it is a
* good idea to use a SessionCache size equal to the number of domains you plan on connecting to.
*
* The implementation for this function can be found at SSLClientImpl::get_session_impl.
*
* @param host A hostname c string, or NULL if one is not availible
* @param ip An IP address
* @returns A reference to an SSLSession object
*/
virtual SSLSession& getSession(const char* host, const IPAddress& addr) { return get_session_impl(host, addr); }
/**
* @brief Clear the session corresponding to a host and IP
*
* The implementation for this function can be found at SSLClientImpl::remove_session_impl.
*
* @param host A hostname c string, or NULL if one is not availible
* @param ip An IP address
*/
virtual void removeSession(const char* host, const IPAddress& addr) { return remove_session_impl(host, addr); }
/**
* @brief Get the meximum number of SSL sessions that can be stored at once
* @returns The SessionCache template parameter.
*/
virtual size_t getSessionCount() const { return SessionCache; }
/**
* @brief Equivalent to SSLClient::connected() > 0
* @returns true if connected, false if not
@ -412,88 +443,15 @@ public:
/** @brief returns a refernence to the client object stored in this class. Take care not to break it. */
C& getClient() { return m_client; }
/**
* @brief Get a sesssion reference corressponding to a host and IP, or a reference to a emptey session if none exist
*
* If no session corresponding to the host and ip exist, then this function will cycle through
* sessions in a rotating order. This allows the ssession cache to continuially store sessions,
* however it will also result in old sessions being cleared and returned. In general, it is a
* good idea to use a SessionCache size equal to the number of domains you plan on connecting to.
*
* @param host A hostname c string, or NULL if one is not availible
* @param ip An IP address
* @returns A reference to an SSLSession object
*/
virtual SSLSession& getSession(const char* host, const IPAddress& addr);
protected:
//virtual Client& get_arduino_client() { return m_client; }
//virtual SSLSession* get_session_array() { return m_sessions; }
/**
* @brief Clear the session corresponding to a host and IP
*
* @param host A hostname c string, or NULL if one is not availible
* @param ip An IP address
*/
virtual void removeSession(const char* host, const IPAddress& addr);
private:
// utility function to find a session index based off of a host and IP
int m_getSessionIndex(const char* host, const IPAddress& addr) const;
// create a copy of the client
C m_client;
// also store an array of SSLSessions, so we can resume communication with multiple websites
SSLSession m_sessions[SessionCache];
// store an index of where a new session can be placed if we don't have any corresponding sessions
size_t m_index;
};
template <class C, size_t SessionCache>
SSLSession& SSLClient<C, SessionCache>::getSession(const char* host, const IPAddress& addr) {
const char* func_name = __func__;
// search for a matching session with the IP
int temp_index = m_getSessionIndex(host, addr);
// if none are availible, use m_index
if (temp_index == -1) {
temp_index = m_index;
// reset the session so we don't try to send one sites session to another
m_sessions[temp_index].clear_parameters();
}
// increment m_index so the session cache is a circular buffer
if (temp_index == m_index && ++m_index >= SessionCache) m_index = 0;
// return the pointed to value
m_info("Using session index: ", func_name);
m_info(temp_index, func_name);
return m_sessions[temp_index];
}
template <class C, size_t SessionCache>
void SSLClient<C, SessionCache>::removeSession(const char* host, const IPAddress& addr) {
const char* func_name = __func__;
int temp_index = m_getSessionIndex(host, addr);
if (temp_index != -1) {
m_info(" Deleted session ", func_name);
m_info(temp_index, func_name);
m_sessions[temp_index].clear_parameters();
}
}
template <class C, size_t SessionCache>
int SSLClient<C, SessionCache>::m_getSessionIndex(const char* host, const IPAddress& addr) const {
const char* func_name = __func__;
// search for a matching session with the IP
for (uint8_t i = 0; i < SessionCache; i++) {
// if we're looking at a real session
if (m_sessions[i].is_valid_session()
&& (
// and the hostname matches, or
(host != NULL && m_sessions[i].get_hostname().equals(host))
// there is no hostname and the IP address matches
|| (host == NULL && addr == m_sessions[i].get_ip())
)) {
m_info("Found session match: ", func_name);
m_info(m_sessions[i].get_hostname(), func_name);
return i;
}
}
// none found
return -1;
}
#endif /** SSLClient_H_ */

89
src/SSLClientImpl.cpp
View file

@ -51,11 +51,14 @@ static int freeMemory() {
/** see SSLClientImpl.h */
SSLClientImpl::SSLClientImpl(Client *client, const br_x509_trust_anchor *trust_anchors,
const size_t trust_anchors_num, const int analog_pin, const DebugLevel debug)
const size_t trust_anchors_num, const int analog_pin, SSLSession* session_ray,
const DebugLevel debug)
: m_client(client)
, m_trust_anchors(trust_anchors)
, m_trust_anchors_num(trust_anchors_num)
, m_analog_pin(analog_pin)
, m_session_ptr(session_ray)
, m_session_index(0)
, m_debug(debug)
, m_write_idx(0) {
@ -90,7 +93,7 @@ int SSLClientImpl::connect_impl(IPAddress ip, uint16_t port) {
return 0;
}
m_info("Base client connected!", func_name);
return m_start_ssl(NULL, getSession(NULL, ip));
return m_start_ssl(NULL, get_session_impl(NULL, ip));
}
/* see SSLClientImpl.h*/
@ -106,7 +109,7 @@ int SSLClientImpl::connect_impl(const char *host, uint16_t port) {
// first, if we have a session, check if we're trying to resolve the same host
// as before
bool connect_ok;
SSLSession& ses = getSession(host, INADDR_NONE);
SSLSession& ses = get_session_impl(host, INADDR_NONE);
if (ses.is_valid_session()) {
// if so, then connect using the stored session
m_info("Connecting using a cached IP", func_name);
@ -187,7 +190,7 @@ int SSLClientImpl::available_impl() {
/** see SSLClientImpl.h */
int SSLClientImpl::read_impl(uint8_t *buf, size_t size) {
// check that the engine is ready to read
if (available() <= 0) return -1;
if (available_impl() <= 0) return -1;
// 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.eng, &alen);
@ -202,7 +205,7 @@ int SSLClientImpl::read_impl(uint8_t *buf, size_t size) {
/** see SSLClientImpl.h */
int SSLClientImpl::peek_impl() {
// check that the engine is ready to read
if (available() <= 0) return -1;
if (available_impl() <= 0) return -1;
// read the buffer, send the ack, and return the bytes read
size_t alen;
uint8_t read_num;
@ -211,7 +214,7 @@ int SSLClientImpl::peek_impl() {
return (int)read_num;
}
/** see SSLClientImpl.h*/
/** see SSLClientImpl.h */
void SSLClientImpl::flush_impl() {
// trigger a flush, incase there's any leftover data
br_ssl_engine_flush(&m_sslctx.eng, 0);
@ -219,7 +222,7 @@ void SSLClientImpl::flush_impl() {
if(m_run_until(BR_SSL_RECVAPP) < 0) m_error("Could not flush write buffer!", __func__);
}
/** see SSLClientImpl.h*/
/** see SSLClientImpl.h */
void SSLClientImpl::stop_impl() {
// tell the SSL connection to gracefully close
br_ssl_engine_close(&m_sslctx.eng);
@ -240,6 +243,7 @@ void SSLClientImpl::stop_impl() {
m_client->stop();
}
/** see SSLClientImpl.h */
uint8_t SSLClientImpl::connected_impl() {
const char* func_name = __func__;
// check all of the error cases
@ -257,7 +261,7 @@ uint8_t SSLClientImpl::connected_impl() {
else m_warn("Socket was dropped unexpectedly (this can be an alternative to closing the connection)", func_name);
// set the write error so the engine doesn't try to close the connection
setWriteError(SSL_CLIENT_WRTIE_ERROR);
stop();
stop_impl();
}
else if (!wr_ok) {
m_error("Not connected because write error is set", func_name);
@ -265,6 +269,36 @@ uint8_t SSLClientImpl::connected_impl() {
return c_con && br_con && wr_ok;
}
/** see SSLClientImpl.h */
SSLSession& SSLClientImpl::get_session_impl(const char* host, const IPAddress& addr) {
const char* func_name = __func__;
// search for a matching session with the IP
int temp_index = m_get_session_index(host, addr);
// if none are availible, use m_session_index
if (temp_index == -1) {
temp_index = m_session_index;
// reset the session so we don't try to send one sites session to another
m_session_ptr[temp_index].clear_parameters();
}
// increment m_session_index so the session cache is a circular buffer
if (temp_index == m_session_index && ++m_session_index >= getSessionCount()) m_session_index = 0;
// return the pointed to value
m_info("Using session index: ", func_name);
m_info(temp_index, func_name);
return m_session_ptr[temp_index];
}
/** see SSLClientImpl.h */
void SSLClientImpl::remove_session_impl(const char* host, const IPAddress& addr) {
const char* func_name = __func__;
int temp_index = m_get_session_index(host, addr);
if (temp_index != -1) {
m_info(" Deleted session ", func_name);
m_info(temp_index, func_name);
m_session_ptr[temp_index].clear_parameters();
}
}
bool SSLClientImpl::m_soft_connected(const char* func_name) {
// check if the socket is still open and such
if (getWriteError()) {
@ -346,7 +380,7 @@ int SSLClientImpl::m_run_until(const unsigned target) {
if (millis() - start > getTimeout()) {
m_error("SSL internals timed out! This could be an internal error or bad data sent from the server", func_name);
setWriteError(SSL_BR_WRITE_ERROR);
stop();
stop_impl();
return -1;
}
// debug
@ -399,7 +433,7 @@ int SSLClientImpl::m_run_until(const unsigned target) {
else {
m_error("SSL engine state is RECVAPP, however the buffer was null! (This is a problem with BearSSL internals)", func_name);
setWriteError(SSL_BR_WRITE_ERROR);
stop();
stop_impl();
return -1;
}
}
@ -446,7 +480,7 @@ unsigned SSLClientImpl::m_update_engine() {
* wait for it.
*/
if (!&m_sslctx.eng.shutdown_recv) return 0;
stop();
stop_impl();
return 0;
}
if (wlen > 0) {
@ -465,7 +499,7 @@ unsigned SSLClientImpl::m_update_engine() {
if (!(state & BR_SSL_SENDAPP)) {
m_error("Error m_write_idx > 0 but the ssl engine is not ready for data", func_name);
setWriteError(SSL_BR_WRITE_ERROR);
stop();
stop_impl();
return 0;
}
// else time to send the application data
@ -476,14 +510,14 @@ unsigned SSLClientImpl::m_update_engine() {
if (alen == 0 || buf == NULL) {
m_error("Engine set write flag but returned null buffer", func_name);
setWriteError(SSL_BR_WRITE_ERROR);
stop();
stop_impl();
return 0;
}
// sanity check
if (alen < m_write_idx) {
m_error("Alen is less than m_write_idx", func_name);
setWriteError(SSL_INTERNAL_ERROR);
stop();
stop_impl();
return 0;
}
// all good? lets send the data
@ -510,7 +544,7 @@ unsigned SSLClientImpl::m_update_engine() {
unsigned char * buf = br_ssl_engine_recvrec_buf(&m_sslctx.eng, &len);
// do we have the record you're looking for?
const auto avail = m_client->available();
if (avail >= len) {
if (avail > 0 && avail >= len) {
int mem = freeMemory();
// check for a stack overflow
// if the stack overflows we basically have to crash, and
@ -531,7 +565,7 @@ unsigned SSLClientImpl::m_update_engine() {
if(mem < 8000) {
m_error("Out of memory! Decrease the number of sessions or the size of m_iobuf", func_name);
setWriteError(SSL_OUT_OF_MEMORY);
stop();
stop_impl();
return 0;
}
m_info("Read bytes from client: ", func_name);
@ -543,7 +577,7 @@ unsigned SSLClientImpl::m_update_engine() {
m_error("Error reading bytes from m_client. Write Error: ", func_name);
m_error(m_client->getWriteError(), func_name);
setWriteError(SSL_CLIENT_WRTIE_ERROR);
stop();
stop_impl();
return 0;
}
if (rlen > 0) {
@ -568,6 +602,27 @@ unsigned SSLClientImpl::m_update_engine() {
}
}
/** see SSLClientImpl.h */
int SSLClientImpl::m_get_session_index(const char* host, const IPAddress& addr) const {
const char* func_name = __func__;
// search for a matching session with the IP
for (uint8_t i = 0; i < getSessionCount(); i++) {
// if we're looking at a real session
if (m_session_ptr[i].is_valid_session()
&& (
// and the hostname matches, or
(host != NULL && m_session_ptr[i].get_hostname().equals(host))
// there is no hostname and the IP address matches
|| (host == NULL && addr == m_session_ptr[i].get_ip())
)) {
m_info("Found session match: ", func_name);
m_info(m_session_ptr[i].get_hostname(), func_name);
return i;
}
}
// none found
return -1;
}
/** See SSLClientImpl.h */
void SSLClientImpl::m_print_prefix(const char* func_name, const DebugLevel level) const

31
src/SSLClientImpl.h
View file

@ -71,7 +71,7 @@ enum DebugLevel {
* On error, any function in this class will terminate the socket.
* TODO: Write what this is */
class SSLClientImpl: public Client {
class SSLClientImpl : public Client {
public:
/**
* @brief initializes SSL contexts for bearSSL
@ -80,22 +80,23 @@ public:
* based off of the domains you want to make SSL connections to. Check out the
* Wiki on the pycert-bearssl tool for a simple way to do this.
* @pre The analog_pin should be set to input.
* @pre The session_ray must be an array of the size returned by SSLClient::getSessionCount()
* filled with SSLSession objects.
*
* @post set_client must be called immediatly after to set the client class
* pointer.
* pointer and Session pointer.
*
* @param trust_anchors Trust anchors used in the verification
* of the SSL server certificate, generated using the `brssl` command
* line utility. For more information see the samples or bearssl.org
* @param trust_anchors_num The number of trust anchors stored
* @param analog_pin An analog pin to pull random bytes from, used in seeding the RNG
* @param get_remote_ip Function pointer to get the remote ip from the client. We
* need this value since the Client abstract class has no remoteIP() function,
* however most of the arduino internet client implementations do.
* @param session_ray A pointer to the array of SSLSessions created by SSLClient
* @param debug whether to enable or disable debug logging, must be constexpr
*/
explicit SSLClientImpl(Client* client, const br_x509_trust_anchor *trust_anchors,
const size_t trust_anchors_num, const int analog_pin, const DebugLevel debug);
const size_t trust_anchors_num, const int analog_pin, SSLSession* session_ray,
const DebugLevel debug);
//============================================
//= Functions implemented in SSLClientImpl.cpp
@ -119,6 +120,10 @@ public:
void stop_impl();
/** @see SSLClient::connected */
uint8_t connected_impl();
/** See SSLClient::getSession */
SSLSession& get_session_impl(const char* host, const IPAddress& addr);
/** See SSLClient::removeSession */
void remove_session_impl(const char* host, const IPAddress& addr);
//============================================
//= Functions implemented in SSLClient.h
@ -129,11 +134,10 @@ public:
virtual IPAddress remoteIP() = 0;
/** See SSLClient::localPort */
virtual uint16_t remotePort() = 0;
/** See SSLClient::getSession */
virtual SSLSession& getSession(const char* host, const IPAddress& addr) = 0;
/** See SSLClient::getSessionCount */
virtual size_t getSessionCount() const = 0;
protected:
//============================================
//= Functions implemented in SSLClientImpl.cpp
//============================================
@ -145,7 +149,7 @@ protected:
* is placed in it's own function for flexibility reasons, but it
* is critical that this function is called before anything else
*/
void set_client(Client* c) { m_client = c; }
void set_client(Client* c, SSLSession* sessions) { m_client = c; m_session_ptr = sessions; }
/** @brief Prints a debugging prefix to all logs, so we can attatch them to useful information */
void m_print_prefix(const char* func_name, const DebugLevel level) const;
@ -186,6 +190,8 @@ private:
int m_run_until(const unsigned target);
/** proxy for availble that returns the state */
unsigned m_update_engine();
/** utility function to find a session index based off of a host and IP */
int m_get_session_index(const char* host, const IPAddress& addr) const;
//============================================
//= Data Members
@ -199,6 +205,11 @@ private:
const size_t m_trust_anchors_num;
// store the pin to fetch an RNG see from
const int m_analog_pin;
// store a pointer to the SSL Session array, since it's size
// is deduced at compile time
SSLSession* m_session_ptr;
// store an index of where a new session can be placed if we don't have any corresponding sessions
size_t m_session_index;
// store whether to enable debug logging
const DebugLevel m_debug;
// store the context values required for SSL