Protocomm : Session security now supports multiple instances of the same type

List of changes:
* Security APIs accept handle to instance created during initialization
* Protocomm internally stores the security instance handle and calls security APIs with this handle as first parameter

components/protocomm/include/security/protocomm_security.h

@@ -35,6 +35,8 @@ typedef struct protocomm_security_pop {
     uint16_t len;
 } protocomm_security_pop_t;
 
+typedef void * protocomm_security_handle_t;
+
 /**
  * @brief   Protocomm security object structure.
  *
@@ -54,28 +56,31 @@ typedef struct protocomm_security {
      * Function for initializing/allocating security
      * infrastructure
      */
-    esp_err_t (*init)();
+    esp_err_t (*init)(protocomm_security_handle_t *handle);
 
     /**
      * Function for deallocating security infrastructure
      */
-    esp_err_t (*cleanup)();
+    esp_err_t (*cleanup)(protocomm_security_handle_t handle);
 
     /**
      * Starts new secure transport session with specified ID
      */
-    esp_err_t (*new_transport_session)(uint32_t session_id);
+    esp_err_t (*new_transport_session)(protocomm_security_handle_t handle,
+                                       uint32_t session_id);
 
     /**
      * Closes a secure transport session with specified ID
      */
-    esp_err_t (*close_transport_session)(uint32_t session_id);
+    esp_err_t (*close_transport_session)(protocomm_security_handle_t handle,
+                                         uint32_t session_id);
 
     /**
      * Handler function for authenticating connection
      * request and establishing secure session
      */
-    esp_err_t (*security_req_handler)(const protocomm_security_pop_t *pop,
+    esp_err_t (*security_req_handler)(protocomm_security_handle_t handle,
+                                      const protocomm_security_pop_t *pop,
                                       uint32_t session_id,
                                       const uint8_t *inbuf, ssize_t inlen,
                                       uint8_t **outbuf, ssize_t *outlen,
@@ -84,14 +89,16 @@ typedef struct protocomm_security {
     /**
      * Function which implements the encryption algorithm
      */
-    esp_err_t (*encrypt)(uint32_t session_id,
+    esp_err_t (*encrypt)(protocomm_security_handle_t handle,
+                         uint32_t session_id,
                          const uint8_t *inbuf, ssize_t inlen,
                          uint8_t *outbuf, ssize_t *outlen);
 
     /**
      * Function which implements the decryption algorithm
      */
-    esp_err_t (*decrypt)(uint32_t session_id,
+    esp_err_t (*decrypt)(protocomm_security_handle_t handle,
+                         uint32_t session_id,
                          const uint8_t *inbuf, ssize_t inlen,
                          uint8_t *outbuf, ssize_t *outlen);
 } protocomm_security_t;

components/protocomm/src/common/protocomm.c

@@ -59,7 +59,7 @@ void protocomm_delete(protocomm_t *pc)
 
     /* Free memory allocated to security */
     if (pc->sec && pc->sec->cleanup) {
-        pc->sec->cleanup();
+        pc->sec->cleanup(pc->sec_inst);
     }
     if (pc->pop) {
         free(pc->pop);
@@ -182,7 +182,7 @@ esp_err_t protocomm_req_handle(protocomm_t *pc, const char *ep_name, uint32_t se
             }
 
             ssize_t dec_inbuf_len = inlen;
-            ret = pc->sec->decrypt(session_id, inbuf, inlen, dec_inbuf, &dec_inbuf_len);
+            ret = pc->sec->decrypt(pc->sec_inst, session_id, inbuf, inlen, dec_inbuf, &dec_inbuf_len);
             if (ret != ESP_OK) {
                 ESP_LOGE(TAG, "Decryption of response failed for endpoint %s", ep_name);
                 free(dec_inbuf);
@@ -214,7 +214,7 @@ esp_err_t protocomm_req_handle(protocomm_t *pc, const char *ep_name, uint32_t se
             }
 
             ssize_t enc_resp_len = plaintext_resp_len;
-            ret = pc->sec->encrypt(session_id, plaintext_resp, plaintext_resp_len,
+            ret = pc->sec->encrypt(pc->sec_inst, session_id, plaintext_resp, plaintext_resp_len,
                                    enc_resp, &enc_resp_len);
 
             if (ret != ESP_OK) {
@@ -253,7 +253,8 @@ static int protocomm_common_security_handler(uint32_t session_id,
     protocomm_t *pc = (protocomm_t *) priv_data;
 
     if (pc->sec && pc->sec->security_req_handler) {
-        return pc->sec->security_req_handler(pc->pop, session_id,
+        return pc->sec->security_req_handler(pc->sec_inst,
+                                             pc->pop, session_id,
                                              inbuf, inlen,
                                              outbuf, outlen,
                                              priv_data);
@@ -283,7 +284,7 @@ esp_err_t protocomm_set_security(protocomm_t *pc, const char *ep_name,
     }
 
     if (sec->init) {
-        ret = sec->init();
+        ret = sec->init(&pc->sec_inst);
         if (ret != ESP_OK) {
             ESP_LOGE(TAG, "Error initializing security");
             protocomm_remove_endpoint(pc, ep_name);
@@ -297,7 +298,8 @@ esp_err_t protocomm_set_security(protocomm_t *pc, const char *ep_name,
         if (pc->pop == NULL) {
             ESP_LOGE(TAG, "Error allocating Proof of Possession");
             if (pc->sec && pc->sec->cleanup) {
-                pc->sec->cleanup();
+                pc->sec->cleanup(pc->sec_inst);
+                pc->sec_inst = NULL;
                 pc->sec = NULL;
             }
 
@@ -316,7 +318,8 @@ esp_err_t protocomm_unset_security(protocomm_t *pc, const char *ep_name)
     }
 
     if (pc->sec && pc->sec->cleanup) {
-        pc->sec->cleanup();
+        pc->sec->cleanup(pc->sec_inst);
+        pc->sec_inst = NULL;
         pc->sec = NULL;
     }
 

components/protocomm/src/common/protocomm_priv.h

@@ -61,10 +61,13 @@ struct protocomm {
      * internally when protocomm_remove_endpoint() is invoked. */
     int (*remove_endpoint)(const char *ep_name);
 
-    /* Pointer to security layer instance to be used internally for
+    /* Pointer to security layer to be used internally for
      * establishing secure sessions */
     const protocomm_security_t *sec;
 
+    /* Handle to the security layer instance */
+    protocomm_security_handle_t sec_inst;
+
     /* Pointer to proof of possession object */
     protocomm_security_pop_t *pop;
 

components/protocomm/src/security/security0.c

@@ -65,7 +65,9 @@ static void sec0_session_setup_cleanup(uint32_t session_id, SessionData *resp)
     return;
 }
 
-static esp_err_t sec0_req_handler(const protocomm_security_pop_t *pop, uint32_t session_id,
+static esp_err_t sec0_req_handler(protocomm_security_handle_t handle,
+                                  const protocomm_security_pop_t *pop,
+                                  uint32_t session_id,
                                   const uint8_t *inbuf, ssize_t inlen,
                                   uint8_t **outbuf, ssize_t *outlen,
                                   void *priv_data)

components/protocomm/src/security/security1.c

@@ -57,8 +57,6 @@ typedef struct session {
     size_t nc_off;
 } session_t;
 
-static session_t *cur_session;
-
 static void flip_endian(uint8_t *data, size_t len)
 {
     uint8_t swp_buf;
@@ -75,7 +73,8 @@ static void hexdump(const char *msg, uint8_t *buf, int len)
     ESP_LOG_BUFFER_HEX_LEVEL(TAG, buf, len, ESP_LOG_DEBUG);
 }
 
-static esp_err_t handle_session_command1(uint32_t session_id,
+static esp_err_t handle_session_command1(session_t *cur_session,
+                                         uint32_t session_id,
                                          SessionData *req, SessionData *resp)
 {
     ESP_LOGD(TAG, "Request to handle setup1_command");
@@ -176,7 +175,8 @@ static esp_err_t handle_session_command1(uint32_t session_id,
     return ESP_OK;
 }
 
-static esp_err_t handle_session_command0(uint32_t session_id,
+static esp_err_t handle_session_command0(session_t *cur_session,
+                                         uint32_t session_id,
                                          SessionData *req, SessionData *resp,
                                          const protocomm_security_pop_t *pop)
 {
@@ -355,23 +355,14 @@ exit_cmd0:
     return ret;
 }
 
-static esp_err_t sec1_session_setup(uint32_t session_id,
+static esp_err_t sec1_session_setup(session_t *cur_session,
+                                    uint32_t session_id,
                                     SessionData *req, SessionData *resp,
                                     const protocomm_security_pop_t *pop)
 {
     Sec1Payload *in = (Sec1Payload *) req->sec1;
     esp_err_t ret;
 
-    if (!cur_session) {
-        ESP_LOGE(TAG, "Invalid session context data");
-        return ESP_ERR_INVALID_ARG;
-    }
-
-    if (session_id != cur_session->id) {
-        ESP_LOGE(TAG, "Invalid session ID : %d (expected %d)", session_id, cur_session->id);
-        return ESP_ERR_INVALID_STATE;
-    }
-
     if (!in) {
         ESP_LOGE(TAG, "Empty session data");
         return ESP_ERR_INVALID_ARG;
@@ -379,10 +370,10 @@ static esp_err_t sec1_session_setup(uint32_t session_id,
 
     switch (in->msg) {
         case SEC1_MSG_TYPE__Session_Command0:
-            ret = handle_session_command0(session_id, req, resp, pop);
+            ret = handle_session_command0(cur_session, session_id, req, resp, pop);
             break;
         case SEC1_MSG_TYPE__Session_Command1:
-            ret = handle_session_command1(session_id, req, resp);
+            ret = handle_session_command1(cur_session, session_id, req, resp);
             break;
         default:
             ESP_LOGE(TAG, "Invalid security message type");
@@ -393,7 +384,7 @@ static esp_err_t sec1_session_setup(uint32_t session_id,
 
 }
 
-static void sec1_session_setup_cleanup(uint32_t session_id, SessionData *resp)
+static void sec1_session_setup_cleanup(session_t *cur_session, uint32_t session_id, SessionData *resp)
 {
     Sec1Payload *out = resp->sec1;
 
@@ -427,11 +418,16 @@ static void sec1_session_setup_cleanup(uint32_t session_id, SessionData *resp)
     return;
 }
 
-static esp_err_t sec1_close_session(uint32_t session_id)
+static esp_err_t sec1_close_session(protocomm_security_handle_t handle, uint32_t session_id)
 {
+    session_t *cur_session = (session_t *) handle;
+    if (!cur_session) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
     if (!cur_session || cur_session->id != session_id) {
         ESP_LOGE(TAG, "Attempt to close invalid session");
-        return ESP_ERR_INVALID_ARG;
+        return ESP_ERR_INVALID_STATE;
     }
 
     if (cur_session->state == SESSION_STATE_DONE) {
@@ -439,48 +435,63 @@ static esp_err_t sec1_close_session(uint32_t session_id)
         mbedtls_aes_free(&cur_session->ctx_aes);
     }
 
-    bzero(cur_session, sizeof(session_t));
-    free(cur_session);
-    cur_session = NULL;
+    memset(cur_session, 0, sizeof(session_t));
+    cur_session->id = -1;
     return ESP_OK;
 }
 
-static esp_err_t sec1_new_session(uint32_t session_id)
+static esp_err_t sec1_new_session(protocomm_security_handle_t handle, uint32_t session_id)
 {
-    if (cur_session) {
-        /* Only one session is allowed at a time */
-        ESP_LOGE(TAG, "Closing old session with id %u", cur_session->id);
-        sec1_close_session(cur_session->id);
+    session_t *cur_session = (session_t *) handle;
+    if (!cur_session) {
+        return ESP_ERR_INVALID_ARG;
     }
 
-    cur_session = (session_t *) calloc(1, sizeof(session_t));
-    if (!cur_session) {
-        ESP_LOGE(TAG, "Error allocating session structure");
-        return ESP_ERR_NO_MEM;
+    if (cur_session->id != -1) {
+        /* Only one session is allowed at a time */
+        ESP_LOGE(TAG, "Closing old session with id %u", cur_session->id);
+        sec1_close_session(cur_session, session_id);
     }
 
     cur_session->id = session_id;
     return ESP_OK;
 }
 
-static esp_err_t sec1_init()
+static esp_err_t sec1_init(protocomm_security_handle_t *handle)
 {
+    if (!handle) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    session_t *cur_session = (session_t *) calloc(1, sizeof(session_t));
+    if (!cur_session) {
+        ESP_LOGE(TAG, "Error allocating new session");
+        return ESP_ERR_NO_MEM;
+    }
+    cur_session->id = -1;
+    *handle = (protocomm_security_handle_t) cur_session;
     return ESP_OK;
 }
 
-static esp_err_t sec1_cleanup()
+static esp_err_t sec1_cleanup(protocomm_security_handle_t handle)
 {
+    session_t *cur_session = (session_t *) handle;
     if (cur_session) {
-        ESP_LOGD(TAG, "Closing current session with id %u", cur_session->id);
-        sec1_close_session(cur_session->id);
+        sec1_close_session(handle, cur_session->id);
     }
+    free(handle);
     return ESP_OK;
 }
 
-static esp_err_t sec1_decrypt(uint32_t session_id,
+static esp_err_t sec1_decrypt(protocomm_security_handle_t handle,
+                              uint32_t session_id,
                               const uint8_t *inbuf, ssize_t inlen,
                               uint8_t *outbuf, ssize_t *outlen)
 {
+    session_t *cur_session = (session_t *) handle;
+    if (!cur_session) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
     if (*outlen < inlen) {
         return ESP_ERR_INVALID_ARG;
     }
@@ -505,11 +516,24 @@ static esp_err_t sec1_decrypt(uint32_t session_id,
     return ESP_OK;
 }
 
-static esp_err_t sec1_req_handler(const protocomm_security_pop_t *pop, uint32_t session_id,
+static esp_err_t sec1_req_handler(protocomm_security_handle_t handle,
+                                  const protocomm_security_pop_t *pop,
+                                  uint32_t session_id,
                                   const uint8_t *inbuf, ssize_t inlen,
                                   uint8_t **outbuf, ssize_t *outlen,
                                   void *priv_data)
 {
+    session_t *cur_session = (session_t *) handle;
+    if (!cur_session) {
+        ESP_LOGE(TAG, "Invalid session context data");
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if (session_id != cur_session->id) {
+        ESP_LOGE(TAG, "Invalid session ID : %d (expected %d)", session_id, cur_session->id);
+        return ESP_ERR_INVALID_STATE;
+    }
+
     SessionData *req;
     SessionData resp;
     esp_err_t ret;
@@ -526,7 +550,7 @@ static esp_err_t sec1_req_handler(const protocomm_security_pop_t *pop, uint32_t
     }
 
     session_data__init(&resp);
-    ret = sec1_session_setup(session_id, req, &resp, pop);
+    ret = sec1_session_setup(cur_session, session_id, req, &resp, pop);
     if (ret != ESP_OK) {
         ESP_LOGE(TAG, "Session setup error %d", ret);
         session_data__free_unpacked(req, NULL);
@@ -544,7 +568,7 @@ static esp_err_t sec1_req_handler(const protocomm_security_pop_t *pop, uint32_t
     }
     session_data__pack(&resp, *outbuf);
 
-    sec1_session_setup_cleanup(session_id, &resp);
+    sec1_session_setup_cleanup(cur_session, session_id, &resp);
     return ESP_OK;
 }
 

components/protocomm/src/transports/protocomm_ble.c

@@ -273,7 +273,8 @@ static void transport_simple_ble_disconnect(esp_gatts_cb_event_t event, esp_gatt
     ESP_LOGD(TAG, "Inside disconnect w/ session - %d", param->disconnect.conn_id);
     if (protoble_internal->pc_ble->sec &&
         protoble_internal->pc_ble->sec->close_transport_session) {
-        ret = protoble_internal->pc_ble->sec->close_transport_session(param->disconnect.conn_id);
+        ret = protoble_internal->pc_ble->sec->close_transport_session(protoble_internal->pc_ble->sec_inst,
+                                                                      param->disconnect.conn_id);
         if (ret != ESP_OK) {
             ESP_LOGE(TAG, "error closing the session after disconnect");
         }
@@ -287,7 +288,8 @@ static void transport_simple_ble_connect(esp_gatts_cb_event_t event, esp_gatt_if
     ESP_LOGD(TAG, "Inside BLE connect w/ conn_id - %d", param->connect.conn_id);
     if (protoble_internal->pc_ble->sec &&
         protoble_internal->pc_ble->sec->new_transport_session) {
-        ret = protoble_internal->pc_ble->sec->new_transport_session(param->connect.conn_id);
+        ret = protoble_internal->pc_ble->sec->new_transport_session(protoble_internal->pc_ble->sec_inst,
+                                                                    param->connect.conn_id);
         if (ret != ESP_OK) {
             ESP_LOGE(TAG, "error creating the session");
         }

components/protocomm/src/transports/protocomm_console.c

@@ -145,7 +145,7 @@ static int common_cmd_handler(int argc, char** argv)
 
     if (cur_session_id != session_id) {
         if (pc_console->sec && pc_console->sec->new_transport_session) {
-            ret = pc_console->sec->new_transport_session(cur_session_id);
+            ret = pc_console->sec->new_transport_session(pc_console->sec_inst, cur_session_id);
             if (ret == ESP_OK) {
                 session_id = cur_session_id;
             }

components/protocomm/src/transports/protocomm_httpd.c

@@ -48,7 +48,7 @@ static esp_err_t common_post_handler(httpd_req_t *req)
             /* Presently HTTP server doesn't support callback on socket closure so
              * previous session can only be closed when new session is requested */
             if (pc_httpd->sec && pc_httpd->sec->close_transport_session) {
-                ret = pc_httpd->sec->close_transport_session(session_id);
+                ret = pc_httpd->sec->close_transport_session(pc_httpd->sec_inst, session_id);
                 if (ret != ESP_OK) {
                     ESP_LOGE(TAG, "Failed to close session with ID: %d", session_id);
                     ret = ESP_FAIL;
@@ -58,7 +58,7 @@ static esp_err_t common_post_handler(httpd_req_t *req)
             session_id = PROTOCOMM_NO_SESSION_ID;
         }
         if (pc_httpd->sec && pc_httpd->sec->new_transport_session) {
-            ret = pc_httpd->sec->new_transport_session(cur_session_id);
+            ret = pc_httpd->sec->new_transport_session(pc_httpd->sec_inst, cur_session_id);
             if (ret != ESP_OK) {
                 ESP_LOGE(TAG, "Failed to launch new session with ID: %d", cur_session_id);
                 ret = ESP_FAIL;