Fix WiFiSecureClient memory leaks when SSL/TLS connection fails #5945
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everslick
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Dec 16, 2021
| @@ -280,7 +283,6 @@ int start_ssl_client(sslclient_context *ssl_client, const char *host, uint32_t p | |||
| memset(buf, 0, sizeof(buf)); | |||
| mbedtls_x509_crt_verify_info(buf, sizeof(buf), " ! ", flags); | |||
| log_e("Failed to verify peer certificate! verification info: %s", buf); | |||
| stop_ssl_socket(ssl_client, rootCABuff, cli_cert, cli_key); //It's not safe continue. | |||
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Why is this call to stop_ssl_socket() not needed anymore? Was it unnecessary to begin with?
| @@ -313,10 +315,20 @@ void stop_ssl_socket(sslclient_context *ssl_client, const char *rootCABuff, cons | |||
| ssl_client->socket = -1; | |||
| } | |||
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| // avoid memory leak if ssl connection attempt failed | |||
| if (ssl_client->ssl_conf.ca_chain != NULL) { | |||
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Testing for NULL is superficial and considered bad taste by some when the pointer is only handed over to free() anyway. The pointers below are not tested and thus this introduces a confusing inconstancy. IMHO.
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This should fix issue #5781 and possibly others related to the same problem: the function
start_ssl_client()does not free memory allocated by mbed-tls library for data structures holding CA certificate, client certificate and private key, in case of early failures (handshake, verification, etc.), but only when the connection is successful.The proposed fix adds some cleanup code to
stop_ssl_socket()so thatWiFiSecureClientdoes not leak memory when it finally callsstop().