esp-idf/components/mbedtls/port/dynamic/esp_mbedtls_dynamic_impl.c
Aditya Patwardhan bf513b6f31 Fix esp_tls: Prevent freeing of global ca store after each connection
when dynamic ssl buffers are enabled
2021-02-25 00:26:13 +00:00

539 lines
13 KiB
C

// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <string.h>
#include "esp_mbedtls_dynamic_impl.h"
#define COUNTER_SIZE (8)
#define CACHE_IV_SIZE (16)
#define CACHE_BUFFER_SIZE (CACHE_IV_SIZE + COUNTER_SIZE)
#define TX_IDLE_BUFFER_SIZE (MBEDTLS_SSL_HEADER_LEN + CACHE_BUFFER_SIZE)
static const char *TAG = "Dynamic Impl";
static void esp_mbedtls_parse_record_header(mbedtls_ssl_context *ssl)
{
ssl->in_msgtype = ssl->in_hdr[0];
ssl->in_msglen = (ssl->in_len[0] << 8) | ssl->in_len[1];
}
static int tx_buffer_len(mbedtls_ssl_context *ssl, int len)
{
(void)ssl;
if (!len) {
return MBEDTLS_SSL_OUT_BUFFER_LEN;
} else {
return len + MBEDTLS_SSL_HEADER_LEN
+ MBEDTLS_SSL_COMPRESSION_ADD
+ MBEDTLS_MAX_IV_LENGTH
+ MBEDTLS_SSL_MAC_ADD
+ MBEDTLS_SSL_PADDING_ADD;
}
}
static void init_tx_buffer(mbedtls_ssl_context *ssl, unsigned char *buf)
{
/**
* In mbedtls, ssl->out_msg = ssl->out_buf + offset;
*/
if (!buf) {
int out_msg_off = (int)ssl->out_msg - (int)ssl->out_buf;
if (!out_msg_off) {
out_msg_off = MBEDTLS_SSL_HEADER_LEN;
}
ssl->out_buf = NULL;
ssl->out_ctr = NULL;
ssl->out_hdr = NULL;
ssl->out_len = NULL;
ssl->out_iv = NULL;
ssl->out_msg = (unsigned char *)out_msg_off;
} else {
int out_msg_off = (int)ssl->out_msg;
ssl->out_buf = buf;
ssl->out_ctr = ssl->out_buf;
ssl->out_hdr = ssl->out_buf + 8;
ssl->out_len = ssl->out_buf + 11;
ssl->out_iv = ssl->out_buf + MBEDTLS_SSL_HEADER_LEN;
ssl->out_msg = ssl->out_buf + out_msg_off;
ESP_LOGV(TAG, "out msg offset is %d", out_msg_off);
}
ssl->out_msgtype = 0;
ssl->out_msglen = 0;
ssl->out_left = 0;
}
static void init_rx_buffer(mbedtls_ssl_context *ssl, unsigned char *buf)
{
/**
* In mbedtls, ssl->in_msg = ssl->in_buf + offset;
*/
if (!buf) {
int in_msg_off = (int)ssl->in_msg - (int)ssl->in_buf;
if (!in_msg_off) {
in_msg_off = MBEDTLS_SSL_HEADER_LEN;
}
ssl->in_buf = NULL;
ssl->in_ctr = NULL;
ssl->in_hdr = NULL;
ssl->in_len = NULL;
ssl->in_iv = NULL;
ssl->in_msg = (unsigned char *)in_msg_off;
} else {
int in_msg_off = (int)ssl->in_msg;
ssl->in_buf = buf;
ssl->in_ctr = ssl->in_buf;
ssl->in_hdr = ssl->in_buf + 8;
ssl->in_len = ssl->in_buf + 11;
ssl->in_iv = ssl->in_buf + MBEDTLS_SSL_HEADER_LEN;
ssl->in_msg = ssl->in_buf + in_msg_off;
ESP_LOGV(TAG, "in msg offset is %d", in_msg_off);
}
ssl->in_msgtype = 0;
ssl->in_msglen = 0;
ssl->in_left = 0;
}
static int esp_mbedtls_alloc_tx_buf(mbedtls_ssl_context *ssl, int len)
{
unsigned char *buf;
if (ssl->out_buf) {
mbedtls_free(ssl->out_buf);
ssl->out_buf = NULL;
}
buf = mbedtls_calloc(1, len);
if (!buf) {
ESP_LOGE(TAG, "alloc(%d bytes) failed", len);
return MBEDTLS_ERR_SSL_ALLOC_FAILED;
}
ESP_LOGV(TAG, "add out buffer %d bytes @ %p", len, buf);
/**
* Mark the out_msg offset from ssl->out_buf.
*
* In mbedtls, ssl->out_msg = ssl->out_buf + offset;
*/
ssl->out_msg = (unsigned char *)MBEDTLS_SSL_HEADER_LEN;
init_tx_buffer(ssl, buf);
return 0;
}
int esp_mbedtls_setup_tx_buffer(mbedtls_ssl_context *ssl)
{
CHECK_OK(esp_mbedtls_alloc_tx_buf(ssl, TX_IDLE_BUFFER_SIZE));
/* mark the out buffer has no data cached */
ssl->out_iv = NULL;
return 0;
}
void esp_mbedtls_setup_rx_buffer(mbedtls_ssl_context *ssl)
{
ssl->in_msg = ssl->in_buf = NULL;
init_rx_buffer(ssl, NULL);
}
int esp_mbedtls_reset_add_tx_buffer(mbedtls_ssl_context *ssl)
{
return esp_mbedtls_alloc_tx_buf(ssl, MBEDTLS_SSL_OUT_BUFFER_LEN);
}
int esp_mbedtls_reset_free_tx_buffer(mbedtls_ssl_context *ssl)
{
ESP_LOGV(TAG, "free out buffer @ %p", ssl->out_buf);
mbedtls_free(ssl->out_buf);
init_tx_buffer(ssl, NULL);
CHECK_OK(esp_mbedtls_setup_tx_buffer(ssl));
return 0;
}
int esp_mbedtls_reset_add_rx_buffer(mbedtls_ssl_context *ssl)
{
unsigned char *buf;
if (ssl->in_buf) {
mbedtls_free(ssl->in_buf);
ssl->in_buf = NULL;
}
buf = mbedtls_calloc(1, MBEDTLS_SSL_IN_BUFFER_LEN);
if (!buf) {
ESP_LOGE(TAG, "alloc(%d bytes) failed", MBEDTLS_SSL_IN_BUFFER_LEN);
return MBEDTLS_ERR_SSL_ALLOC_FAILED;
}
ESP_LOGV(TAG, "add in buffer %d bytes @ %p", MBEDTLS_SSL_IN_BUFFER_LEN, buf);
/**
* Mark the in_msg offset from ssl->in_buf.
*
* In mbedtls, ssl->in_msg = ssl->in_buf + offset;
*/
ssl->in_msg = (unsigned char *)MBEDTLS_SSL_HEADER_LEN;
init_rx_buffer(ssl, buf);
return 0;
}
void esp_mbedtls_reset_free_rx_buffer(mbedtls_ssl_context *ssl)
{
ESP_LOGV(TAG, "free in buffer @ %p", ssl->in_buf);
mbedtls_free(ssl->in_buf);
init_rx_buffer(ssl, NULL);
}
int esp_mbedtls_add_tx_buffer(mbedtls_ssl_context *ssl, size_t buffer_len)
{
int ret = 0;
int cached = 0;
unsigned char *buf;
unsigned char cache_buf[CACHE_BUFFER_SIZE];
ESP_LOGV(TAG, "--> add out");
if (ssl->out_buf) {
if (ssl->out_iv) {
ESP_LOGV(TAG, "out buffer is not empty");
ret = 0;
goto exit;
} else {
memcpy(cache_buf, ssl->out_buf, CACHE_BUFFER_SIZE);
mbedtls_free(ssl->out_buf);
init_tx_buffer(ssl, NULL);
cached = 1;
}
}
buffer_len = tx_buffer_len(ssl, buffer_len);
buf = mbedtls_calloc(1, buffer_len);
if (!buf) {
ESP_LOGE(TAG, "alloc(%d bytes) failed", buffer_len);
ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
goto exit;
}
ESP_LOGV(TAG, "add out buffer %d bytes @ %p", buffer_len, buf);
init_tx_buffer(ssl, buf);
if (cached) {
memcpy(ssl->out_ctr, cache_buf, COUNTER_SIZE);
memcpy(ssl->out_iv, cache_buf + COUNTER_SIZE, CACHE_IV_SIZE);
}
ESP_LOGV(TAG, "ssl->out_buf=%p ssl->out_msg=%p", ssl->out_buf, ssl->out_msg);
exit:
ESP_LOGV(TAG, "<-- add out");
return ret;
}
int esp_mbedtls_free_tx_buffer(mbedtls_ssl_context *ssl)
{
int ret = 0;
unsigned char buf[CACHE_BUFFER_SIZE];
unsigned char *pdata;
ESP_LOGV(TAG, "--> free out");
if (!ssl->out_buf || (ssl->out_buf && !ssl->out_iv)) {
ret = 0;
goto exit;
}
memcpy(buf, ssl->out_ctr, COUNTER_SIZE);
memcpy(buf + COUNTER_SIZE, ssl->out_iv, CACHE_IV_SIZE);
ESP_LOGV(TAG, "free out buffer @ %p", ssl->out_buf);
mbedtls_free(ssl->out_buf);
init_tx_buffer(ssl, NULL);
pdata = mbedtls_calloc(1, TX_IDLE_BUFFER_SIZE);
if (!pdata) {
ESP_LOGE(TAG, "alloc(%d bytes) failed", TX_IDLE_BUFFER_SIZE);
return MBEDTLS_ERR_SSL_ALLOC_FAILED;
}
memcpy(pdata, buf, CACHE_BUFFER_SIZE);
init_tx_buffer(ssl, pdata);
ssl->out_iv = NULL;
exit:
ESP_LOGV(TAG, "<-- free out");
return ret;
}
int esp_mbedtls_add_rx_buffer(mbedtls_ssl_context *ssl)
{
int cached = 0;
int ret = 0;
int buffer_len;
unsigned char *buf;
unsigned char cache_buf[16];
unsigned char msg_head[5];
size_t in_msglen, in_left;
ESP_LOGV(TAG, "--> add rx");
if (ssl->in_buf) {
if (ssl->in_iv) {
ESP_LOGV(TAG, "in buffer is not empty");
ret = 0;
goto exit;
} else {
cached = 1;
}
}
ssl->in_hdr = msg_head;
ssl->in_len = msg_head + 3;
if ((ret = mbedtls_ssl_fetch_input(ssl, mbedtls_ssl_hdr_len(ssl))) != 0) {
if (ret == MBEDTLS_ERR_SSL_TIMEOUT) {
ESP_LOGD(TAG, "mbedtls_ssl_fetch_input reads data times out");
} else if (ret == MBEDTLS_ERR_SSL_WANT_READ) {
ESP_LOGD(TAG, "mbedtls_ssl_fetch_input wants to read more data");
} else {
ESP_LOGE(TAG, "mbedtls_ssl_fetch_input error=-0x%x", -ret);
}
goto exit;
}
esp_mbedtls_parse_record_header(ssl);
in_left = ssl->in_left;
in_msglen = ssl->in_msglen;
buffer_len = tx_buffer_len(ssl, in_msglen);
ESP_LOGV(TAG, "message length is %d RX buffer length should be %d left is %d",
(int)in_msglen, (int)buffer_len, (int)ssl->in_left);
if (cached) {
memcpy(cache_buf, ssl->in_buf, 16);
mbedtls_free(ssl->in_buf);
init_rx_buffer(ssl, NULL);
}
buf = mbedtls_calloc(1, buffer_len);
if (!buf) {
ESP_LOGE(TAG, "alloc(%d bytes) failed", buffer_len);
ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
goto exit;
}
ESP_LOGV(TAG, "add in buffer %d bytes @ %p", buffer_len, buf);
init_rx_buffer(ssl, buf);
if (cached) {
memcpy(ssl->in_ctr, cache_buf, 8);
memcpy(ssl->in_iv, cache_buf + 8, 8);
}
memcpy(ssl->in_hdr, msg_head, in_left);
ssl->in_left = in_left;
ssl->in_msglen = 0;
exit:
ESP_LOGV(TAG, "<-- add rx");
return ret;
}
int esp_mbedtls_free_rx_buffer(mbedtls_ssl_context *ssl)
{
int ret = 0;
unsigned char buf[16];
unsigned char *pdata;
ESP_LOGV(TAG, "--> free rx");
/**
* When have read multi messages once, can't free the input buffer directly.
*/
if (!ssl->in_buf || (ssl->in_hslen && (ssl->in_hslen < ssl->in_msglen)) ||
(ssl->in_buf && !ssl->in_iv)) {
ret = 0;
goto exit;
}
/**
* The previous processing is just skipped, so "ssl->in_msglen = 0"
*/
if (!ssl->in_msgtype) {
goto exit;
}
memcpy(buf, ssl->in_ctr, 8);
memcpy(buf + 8, ssl->in_iv, 8);
ESP_LOGV(TAG, "free in buffer @ %p", ssl->out_buf);
mbedtls_free(ssl->in_buf);
init_rx_buffer(ssl, NULL);
pdata = mbedtls_calloc(1, 16);
if (!pdata) {
ESP_LOGE(TAG, "alloc(%d bytes) failed", 16);
ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
goto exit;
}
memcpy(pdata, buf, 16);
init_rx_buffer(ssl, pdata);
ssl->in_iv = NULL;
exit:
ESP_LOGV(TAG, "<-- free rx");
return ret;
}
size_t esp_mbedtls_get_crt_size(mbedtls_x509_crt *cert, size_t *num)
{
size_t n = 0;
size_t bytes = 0;
while (cert) {
bytes += cert->raw.len;
n++;
cert = cert->next;
}
*num = n;
return bytes;
}
#ifdef CONFIG_MBEDTLS_DYNAMIC_FREE_CONFIG_DATA
void esp_mbedtls_free_dhm(mbedtls_ssl_context *ssl)
{
mbedtls_mpi_free((mbedtls_mpi *)&ssl->conf->dhm_P);
mbedtls_mpi_free((mbedtls_mpi *)&ssl->conf->dhm_G);
}
void esp_mbedtls_free_keycert(mbedtls_ssl_context *ssl)
{
mbedtls_ssl_config *conf = (mbedtls_ssl_config *)ssl->conf;
mbedtls_ssl_key_cert *keycert = conf->key_cert, *next;
while (keycert) {
next = keycert->next;
if (keycert) {
mbedtls_free(keycert);
}
keycert = next;
}
conf->key_cert = NULL;
}
void esp_mbedtls_free_keycert_key(mbedtls_ssl_context *ssl)
{
mbedtls_ssl_key_cert *keycert = ssl->conf->key_cert;
while (keycert) {
if (keycert->key) {
mbedtls_pk_free(keycert->key);
keycert->key = NULL;
}
keycert = keycert->next;
}
}
void esp_mbedtls_free_keycert_cert(mbedtls_ssl_context *ssl)
{
mbedtls_ssl_key_cert *keycert = ssl->conf->key_cert;
while (keycert) {
if (keycert->cert) {
mbedtls_x509_crt_free(keycert->cert);
keycert->cert = NULL;
}
keycert = keycert->next;
}
}
#endif /* CONFIG_MBEDTLS_DYNAMIC_FREE_CONFIG_DATA */
#ifdef CONFIG_MBEDTLS_DYNAMIC_FREE_CA_CERT
void esp_mbedtls_free_cacert(mbedtls_ssl_context *ssl)
{
if (ssl->conf->ca_chain) {
mbedtls_ssl_config *conf = (mbedtls_ssl_config *)ssl->conf;
mbedtls_x509_crt_free(conf->ca_chain);
conf->ca_chain = NULL;
}
}
#endif /* CONFIG_MBEDTLS_DYNAMIC_FREE_CA_CERT */
#ifdef CONFIG_MBEDTLS_DYNAMIC_FREE_PEER_CERT
void esp_mbedtls_free_peer_cert(mbedtls_ssl_context *ssl)
{
if (ssl->session_negotiate->peer_cert) {
mbedtls_x509_crt_free( ssl->session_negotiate->peer_cert );
mbedtls_free( ssl->session_negotiate->peer_cert );
ssl->session_negotiate->peer_cert = NULL;
}
}
bool esp_mbedtls_ssl_is_rsa(mbedtls_ssl_context *ssl)
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK) {
return true;
} else {
return false;
}
}
#endif