From f61706cbac43e2eef41e90ef98326cebec5a4d54 Mon Sep 17 00:00:00 2001
From: Stefan Eissing <stefan@eissing.org>
Date: Thu, 31 Jul 2025 11:26:12 +0200
Subject: [PATCH] In CURLWS_RAW_MODE, to not add an encoding reader, so clients
 can send raw frames.

---
 docs/libcurl/opts/CURLOPT_WS_OPTIONS.md |  1 +
 lib/ws.c                                | 27 ++++++++++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/docs/libcurl/opts/CURLOPT_WS_OPTIONS.md b/docs/libcurl/opts/CURLOPT_WS_OPTIONS.md
index 35ae17cf47..998fb16f09 100644
--- a/docs/libcurl/opts/CURLOPT_WS_OPTIONS.md
+++ b/docs/libcurl/opts/CURLOPT_WS_OPTIONS.md
@@ -39,6 +39,7 @@ Available bits in the bitmask
 ## CURLWS_RAW_MODE (1)
 
 Deliver "raw" WebSocket traffic to the CURLOPT_WRITEFUNCTION(3)
+callback. Read "raw" WebSocket traffic from the CURLOPT_READFUNCTION(3)
 callback.
 
 In raw mode, libcurl does not handle pings or any other frame for the
diff --git a/lib/ws.c b/lib/ws.c
index 7217edc158..55579b7fde 100644
--- a/lib/ws.c
+++ b/lib/ws.c
@@ -1185,15 +1185,17 @@ CURLcode Curl_ws_accept(struct Curl_easy *data,
       if(result)
         goto out;
 
-      /* Add our client readerr encoding WS BINARY frames */
-      result = Curl_creader_create(&ws_enc_reader, data, &ws_cr_encode,
-                                   CURL_CR_CONTENT_ENCODE);
-      if(result)
-        goto out;
-      result = Curl_creader_add(data, ws_enc_reader);
-      if(result)
-        goto out;
-      ws_enc_reader = NULL; /* owned by transfer now */
+      if(!data->set.ws_raw_mode) {
+        /* Add our client readerr encoding WS BINARY frames */
+        result = Curl_creader_create(&ws_enc_reader, data, &ws_cr_encode,
+                                     CURL_CR_CONTENT_ENCODE);
+        if(result)
+          goto out;
+        result = Curl_creader_add(data, ws_enc_reader);
+        if(result)
+          goto out;
+        ws_enc_reader = NULL; /* owned by transfer now */
+      }
 
       /* start over with sending */
       data->req.eos_read = FALSE;
@@ -1723,6 +1725,13 @@ CURL_EXTERN CURLcode curl_ws_start_frame(CURL *d,
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = d;
 
+  if(!GOOD_EASY_HANDLE(data))
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+  if(data->set.ws_raw_mode) {
+    failf(data, "cannot curl_ws_start_frame() with CURLWS_RAW_MODE enabled");
+    return CURLE_FAILED_INIT;
+  }
+
   CURL_TRC_WS(data, "curl_start_frame(flags=%x, frame_len=%" FMT_OFF_T,
               flags, frame_len);