Segmentation Fault in Message.MarshalJSON

[marc921]

Using the library as

import (
     nmsg "github.com/farsightsec/go-nmsg/cgo-nmsg"
)

I have experienced segmentation faults

[signal SIGSEGV: segmentation violation code=0x1 addr=0x4 pc=0x7f3435645bbf]

coming from nmsg.Message.MarshalJSON function, called with roughly these steps:

// Receiving messages from UDP connection
reader, err := net.ListenUDP("udp", &src)
input := nmsg.NewInput(h.reader)
// msg is of type *nmsg.Message
msg, err := input.Read()
jsonBytes, err := msg.MarshalJSON()  // SIGSEGV is thrown

This does not happen on all received messages, only few of them. I have not been able to capture a faulty message.
Any advice would be greatly appreciated in that regard too.

I have been looking in the nmsg library C code (message.c) but could not find the source of the error.
I wondered if faulty messages had a special type, attribute or value that made them fall in special edge cases, but could not log it from Go-accessible library functions on nmsg.Message type.

Expected behaviour:
MarshalJSON should return a non-nil error instead of panicking.

[askeydeteque]

It looks like you are using the cgo-nmsg bindings. I remember seeing somewhere the these were not concurrency safe, although I am having trouble finding that statement again. If you are attempting to use that function in multiple goroutines that might be the cause for the panic.