mqtt: fix Curl_read() error handling while reading remaining length

Detected by Coverity. CID 1462320.

Closes #5274

diff --git a/lib/mqtt.c b/lib/mqtt.c
index 35c1b3e8333846532c81b51c3af911fba67c0aae..44433361b35b63c6cbc650ddd81444f4a26ea36f 100644 (file)
--- a/lib/mqtt.c
+++ b/lib/mqtt.c
@@ -569,6 +569,8 @@ static CURLcode mqtt_doing(struct connectdata *conn, bool *done)
         Curl_debug(data, CURLINFO_HEADER_IN, (char *)&byte, 1);
       pkt[mq->npacket++] = byte;
     } while((byte & 0x80) && (mq->npacket < 4));
+    if(result)
+      break;
     mq->remaining_length = mqtt_decode_len(&pkt[0], mq->npacket, NULL);
     mq->npacket = 0;
     if(mq->remaining_length) {