NULL terminate received strings and message payload

2 files changed, 9 insertions, 2 deletions

diff --git a/src/deserialize.c b/src/deserialize.c
index 7f3da7c..aaff490 100644
--- a/src/deserialize.c
+++ b/src/deserialize.c
@@ -109,12 +109,16 @@ static int MqttPacketPublishDeserialize(MqttPacketPublish **packet, Stream *stre
 
     LOG_DEBUG("reading payload payloadSize:%lu\n", payloadSize);
 
-    (*packet)->message = bfromcstralloc(payloadSize, "");
+    /* Allocate extra byte for a NULL terminator. If the user tries to print
+       the payload directly. */
+
+    (*packet)->message = bfromcstralloc(payloadSize+1, "");
 
     if (StreamRead(bdata((*packet)->message), payloadSize, stream) == -1)
         return -1;
 
     (*packet)->message->slen = payloadSize;
+    (*packet)->message->data[payloadSize] = '\0';
 
     return 0;
 }
diff --git a/src/stream_mqtt.c b/src/stream_mqtt.c
index c9d0e12..3864ef3 100644
--- a/src/stream_mqtt.c
+++ b/src/stream_mqtt.c
@@ -10,7 +10,9 @@ int64_t StreamReadMqttString(bstring *buf, Stream *stream)
     if (StreamReadUint16Be(&len, stream) == -1)
         return -1;
 
-    result = bfromcstralloc(len, "");
+    /* We need 1 extra byte for a NULL terminator. bfromcstralloc doesn't do
+       any size snapping. */
+    result = bfromcstralloc(len+1, "");
 
     if (!result)
         return -1;
@@ -22,6 +24,7 @@ int64_t StreamReadMqttString(bstring *buf, Stream *stream)
     }
 
     result->slen = len;
+    result->data[len] = '\0';
 
     *buf = result;