[lwip-devel] [bug #53103] MQTT corrupted mesages

[David Bourgeois]

URL:
  <http://savannah.nongnu.org/bugs/?53103>

                 Summary: MQTT corrupted mesages 
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: jaguarondi
            Submitted on: Fri 09 Feb 2018 02:44:47 AM UTC
                Category: apps
                Severity: 3 - Normal
              Item Group: Crash Error
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None
            lwIP version: git head

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Details:

In the attached wireshark capture, we can see a series of corrupted messages
in packet 454,  which trigger a disconnection by the broker.

It is difficult to debug, but from what we could gather, it seems that an
ERR_MEM produced by the altcp_write is not handled, and it somehow corrupts
the ring buffer.

The capture has been produced by the following code:


extern mqtt_client_t *mqtt_client;
int ip[4] = {10,192,55,55};
mqtt_connect(ip, "client_test");
char topic[64];
char payload[64];
int  counter=0;
while(1){
    sprintf(topic, "topic/test/%d", counter);
    sprintf(payload, "packet %d", counter);
    mqtt_publish(mqtt_client, topic, payload, strlen(payload), MQTT_QOS_1, 0,
NULL, NULL);        
    ++counter;
    if (counter%10 == 0){
        osDelay(10);
    }
}




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File Attachments:


-------------------------------------------------------
Date: Fri 09 Feb 2018 02:44:47 AM UTC  Name: mqtt_garbage_capture.pcapng.gz 
Size: 13KiB   By: jaguarondi
Wireshark capture of the bug triggered by the example code
<http://savannah.nongnu.org/bugs/download.php?file_id=43211>

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