Possible bug with SCTP and iperf3?

[Manas Bhatnagar]

Hello,

I experienced a hard reset of a system recently, running FreeBSD
10-RELEASE, while running iperf3. I do not know much about SCTP nor
iperf3, I was just fiddling around with iperf3 arguments. These are
the commands I ran:

iperf3 -c $IP -P 32 -t 60
iperf3 -u -c $IP -P 32 -t 60
iperf3 --sctp -c $IP -P 32 -t 60
iperf3 --sctp -c $IP -P 4 -t 60
iperf3 --sctp -c $IP -t 60
iperf3 --sctp --nstreams 64 -c $IP -P 32 -t 60
iperf3 --sctp --nstreams 2 -c $IP -P 32 -t 60

What I remember is that the second last command would not show any
data as being transferred and when I ran the last command, the system
running the iperf3 server did a hard reset.

I don't know if this is a bug or not but it seems to my inexperienced
eyes like it is something that could be used maliciously to bring down
a system running 'iperf3 -s' and so I thought it would be best to
share this with the mailing list.

Thank you,
Manas

[Eduardo Morras via freebsd-questions]

On Sun, 29 May 2016 14:45:14 -0400

Post by Manas Bhatnagar
Hello,
I experienced a hard reset of a system recently, running FreeBSD
10-RELEASE, while running iperf3. I do not know much about SCTP nor
iperf3, I was just fiddling around with iperf3 arguments. These are
iperf3 -c $IP -P 32 -t 60
iperf3 -u -c $IP -P 32 -t 60
iperf3 --sctp -c $IP -P 32 -t 60
iperf3 --sctp -c $IP -P 4 -t 60
iperf3 --sctp -c $IP -t 60
iperf3 --sctp --nstreams 64 -c $IP -P 32 -t 60
iperf3 --sctp --nstreams 2 -c $IP -P 32 -t 60
What I remember is that the second last command would not show any
data as being transferred and when I ran the last command, the system
running the iperf3 server did a hard reset.

How do you run the server? Had you a log file? Did you run it as root? Try:

%iperf3 -s -D -V --logfile filename

Can you run the last 2 with -V -R --get-server-output --logfile filename?

%iperf3 --sctp --nstreams 2 -c $IP -P 32 -t 60 -V -R --get-server-output filename

Didn't -P for tcp/udp connections only for emulate sctp multistream capability? AFAIK you don't need both.

Post by Manas Bhatnagar
I don't know if this is a bug or not but it seems to my inexperienced
eyes like it is something that could be used maliciously to bring down
a system running 'iperf3 -s' and so I thought it would be best to
share this with the mailing list.

Thanks to you.

Post by Manas Bhatnagar
Thank you,
Manas

--- ---
Eduardo Morras <***@yahoo.es>

[Manas Bhatnagar]

Hello Eduardo :)
The server was run as root using 'iperf3 -s'

Post by Eduardo Morras via freebsd-questions
Didn't -P for tcp/udp connections only for emulate sctp multistream capability? AFAIK you don't need both.

Yeah, I can't claim to know what I was doing when I ran those
commands. You're probably right about not needing both. I saw the
arguments in the manual and thought I'd try some of them out (though,
in retrospect, I really should not have been running the server as
root).

Unfortunately the system that was running this is currently performing
other tasks and I can't risk a reboot. I will try to find another
system that I can test on and get back to you.

Thanks for you response,
Manas