From a3ede758427fa5c6627476438a4ba0ccdf0dd4c9 Mon Sep 17 00:00:00 2001
From: "Sergio R. Caprile" <scaprile@cesanta.com>
Date: Thu, 3 Nov 2022 11:26:08 -0300
Subject: [PATCH] Accept zero-length payload messages

---
 mongoose.c | 2 +-
 src/mqtt.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mongoose.c b/mongoose.c
index 1ebd29c9..d5189943 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -3195,7 +3195,7 @@ int mg_mqtt_parse(const uint8_t *buf, size_t len, uint8_t version,
         m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
         p += 2;
       }
-      if (p >= end) return MQTT_MALFORMED;
+      if (p > end) return MQTT_MALFORMED;
       if (version == 5) p += 1 + p[0];  // Skip options
       if (p > end) return MQTT_MALFORMED;
       m->data.ptr = (char *) p;
diff --git a/src/mqtt.c b/src/mqtt.c
index 5c712be4..1dffea3e 100644
--- a/src/mqtt.c
+++ b/src/mqtt.c
@@ -172,7 +172,7 @@ int mg_mqtt_parse(const uint8_t *buf, size_t len, uint8_t version,
         m->id = (uint16_t) ((((uint16_t) p[0]) << 8) | p[1]);
         p += 2;
       }
-      if (p >= end) return MQTT_MALFORMED;
+      if (p > end) return MQTT_MALFORMED;
       if (version == 5) p += 1 + p[0];  // Skip options
       if (p > end) return MQTT_MALFORMED;
       m->data.ptr = (char *) p;