From: x2018 <xkernel.wang@foxmail.com>
Date: Sun, 9 Nov 2025 11:19:13 +0000 (+0800)
Subject: mqtt: properly handle the message which exceeds maxsize
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=87149c8383f7cdc85cd4780256afc1b5a923bac8;p=thirdparty%2Fcurl.git

mqtt: properly handle the message which exceeds maxsize

We should goto fail as topic is allocated.

Follow-up to 92fd791

Closes #19417
---

diff --git a/lib/mqtt.c b/lib/mqtt.c
index bac319e63a..713e4aa02c 100644
--- a/lib/mqtt.c
+++ b/lib/mqtt.c
@@ -613,8 +613,10 @@ static CURLcode mqtt_publish(struct Curl_easy *data)
 
   remaininglength = payloadlen + 2 + topiclen;
   encodelen = mqtt_encode_len(encodedbytes, remaininglength);
-  if(MAX_MQTT_MESSAGE_SIZE - remaininglength - 1 < encodelen)
-    return CURLE_TOO_LARGE;
+  if(MAX_MQTT_MESSAGE_SIZE - remaininglength - 1 < encodelen) {
+    result = CURLE_TOO_LARGE;
+    goto fail;
+  }
 
   /* add the control byte and the encoded remaining length */
   pkt = malloc(remaininglength + 1 + encodelen);