res_http_websocket: ensure control frames do not interfere with data

Control frames (PING / PONG / CLOSE) can be received in the middle of a
fragmented message. In order to ensure they do not interfere with the
reassembly buffer, we exit early and do not return the payload to the
caller.

ASTERISK-28257 #close

Change-Id: Ia5367144fe08ac6141bba3309517a48ec7f013bc

diff --git a/res/res_http_websocket.c b/res/res_http_websocket.c
index 2ac5541430ec155645b494510ec2ad39b0a0f582..e8301df204c7448afde54a373c91406162b6c7f6 100644 (file)
--- a/res/res_http_websocket.c
+++ b/res/res_http_websocket.c
@@ -617,9 +617,17 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
                }
 
                /* Per the RFC for PING we need to send back an opcode with the application data as received */
-               if ((*opcode == AST_WEBSOCKET_OPCODE_PING) && (ast_websocket_write(session, AST_WEBSOCKET_OPCODE_PONG, *payload, *payload_len))) {
+               if (*opcode == AST_WEBSOCKET_OPCODE_PING) {
+                       if (ast_websocket_write(session, AST_WEBSOCKET_OPCODE_PONG, *payload, *payload_len)) {
+                               ast_websocket_close(session, 1009);
+                       }
+                       *payload_len = 0;
+                       return 0;
+               }
+
+               /* Stop PONG processing here */
+               if (*opcode == AST_WEBSOCKET_OPCODE_PONG) {
                        *payload_len = 0;
-                       ast_websocket_close(session, 1009);
                        return 0;
                }
 
@@ -633,6 +641,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
                        return 0;
                }
 
+               /* Below this point we are handling TEXT, BINARY or CONTINUATION opcodes */
                if (*payload_len) {
                        if (!(new_payload = ast_realloc(session->payload, (session->payload_len + *payload_len)))) {
                                ast_log(LOG_WARNING, "Failed allocation: %p, %zu, %"PRIu64"\n",