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Fix WiFiSecureClient memory leaks when SSL/TLS connection fails #5945

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Merged
merged 1 commit into from
Dec 14, 2021
Merged

Fix WiFiSecureClient memory leaks when SSL/TLS connection fails #5945

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20 changes: 16 additions & 4 deletions libraries/WiFiClientSecure/src/ssl_client.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,8 @@ static int _handle_error(int err, const char * function, int line)

void ssl_init(sslclient_context *ssl_client)
{
// reset embedded pointers to zero
memset(ssl_client, 0, sizeof(sslclient_context));
mbedtls_ssl_init(&ssl_client->ssl_ctx);
mbedtls_ssl_config_init(&ssl_client->ssl_conf);
mbedtls_ctr_drbg_init(&ssl_client->drbg_ctx);
Expand Down Expand Up @@ -232,6 +234,7 @@ int start_ssl_client(sslclient_context *ssl_client, const char *host, uint32_t p
ret = mbedtls_pk_parse_key(&ssl_client->client_key, (const unsigned char *)cli_key, strlen(cli_key) + 1, NULL, 0);

if (ret != 0) {
mbedtls_x509_crt_free(&ssl_client->client_cert); // cert+key are free'd in pair
return handle_error(ret);
}

Expand All @@ -243,7 +246,7 @@ int start_ssl_client(sslclient_context *ssl_client, const char *host, uint32_t p
// Hostname set here should match CN in server certificate
if((ret = mbedtls_ssl_set_hostname(&ssl_client->ssl_ctx, host)) != 0){
return handle_error(ret);
}
}

mbedtls_ssl_conf_rng(&ssl_client->ssl_conf, mbedtls_ctr_drbg_random, &ssl_client->drbg_ctx);

Expand All @@ -260,8 +263,8 @@ int start_ssl_client(sslclient_context *ssl_client, const char *host, uint32_t p
return handle_error(ret);
}
if((millis()-handshake_start_time)>ssl_client->handshake_timeout)
return -1;
vTaskDelay(2);//2 ticks
return -1;
vTaskDelay(2);//2 ticks
}


Expand All @@ -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?

return handle_error(ret);
} else {
log_v("Certificate verified.");
Expand Down Expand Up @@ -313,10 +315,20 @@ void stop_ssl_socket(sslclient_context *ssl_client, const char *rootCABuff, cons
ssl_client->socket = -1;
}

// 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.

mbedtls_x509_crt_free(&ssl_client->ca_cert);
}
if (ssl_client->ssl_conf.key_cert != NULL) {
mbedtls_x509_crt_free(&ssl_client->client_cert);
mbedtls_pk_free(&ssl_client->client_key);
}
mbedtls_ssl_free(&ssl_client->ssl_ctx);
mbedtls_ssl_config_free(&ssl_client->ssl_conf);
mbedtls_ctr_drbg_free(&ssl_client->drbg_ctx);
mbedtls_entropy_free(&ssl_client->entropy_ctx);
// reset embedded pointers to zero
memset(ssl_client, 0, sizeof(sslclient_context));
}


Expand Down