[tor-dev] Stegotorus now available from gitweb.torproject.org

[David Fifield]

On Mon, Jun 04, 2012 at 04:09:04PM -0700, Zack Weinberg wrote:
> On Mon, Jun 4, 2012 at 8:21 AM, Zack Weinberg <zackw at panix.com> wrote:
> > For the moment, the source tree is visible on Github:
> > <https://github.com/zackw/stegotorus>.  It is likely to move to
> > gitweb.torproject.org hosting in the near future.
> 
> You can now clone {git,https}://git.torproject.org/stegotorus.git .
> Be warned that due to a couple of very large files, a clone requires
> approximately 350MB of disk space and 140MB transferred over the
> network.  (The troublesome files are unlikely to change in the near
> future, so this is a one-time cost.)  You should also assume that all
> documentation is out of date until further notice.
> 
> Patches are welcome.  The TODO list currently exists only in my head,
> but I'll be getting that updated in-repo Real Soon.

I tried these steps and got a segmentation fault:

$ git clone https://git.torproject.org/stegotorus.git
$ cd stegotorus
$ autoreconf -i
$ ./configure && make
$ ./stegotorus null socks 127.0.0.1:5000
[info] ./stegotorus process 28359 now initialized
$ tor ClientTransportPlugin "stegotorus socks4 127.0.0.1:5000" UseBridges 1 Bridge "stegotorus 87.73.82.145:8080"

I found the bridge IP address in scripts/torrc. At this point stegotorus
printed out:

[info] 127.0.0.1:5000: new connection to socks client from 127.0.0.1:42233
[info] <1> trying to connect to 87.73.82.145:8080
[info] <1.1> network error in read: Connection reset by peer

[error] Segmentation fault at 0000000000000010
./stegotorus[0x4054b6]
/lib/x86_64-linux-gnu/libc.so.6(+0x324f0)[0x7fcff4cee4f0]
./stegotorus[0x40ec11]
./stegotorus[0x405f7a]
/usr/lib/libevent-2.0.so.5(+0x1bc4a)[0x7fcff5df8c4a]
/usr/lib/libevent-2.0.so.5(event_base_loop+0x414)[0x7fcff5dee254]
./stegotorus[0x404e76]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd)[0x7fcff4cdaead]
./stegotorus[0x405291]
Segmentation fault

I noticed that the start-stegotorus.sh script uses Socks4Proxy instead
of ClientTransportPlugin, but that gives me the same segfault. Here's
what GDB says:

[info] <1> trying to connect to 87.73.82.145:8080
[info] <1.1> network error in read: Connection reset by peer

Program received signal SIGSEGV, Segmentation fault.
0x000000000040760a in conn_t::outbound (this=0x0) at src/connections.h:43
43        { return this->buffer ? bufferevent_get_output(this->buffer) : 0; }
(gdb) bt
#0  0x000000000040760a in conn_t::outbound (this=0x0) at src/connections.h:43
#1  0x00000000004196f9 in (anonymous namespace)::null_circuit_t::send (this=0x63fd30) at src/protocol/null.cc:202
#2  0x00000000004070aa in circuit_send (ckt=0x63fd30) at src/connections.cc:241
#3  0x000000000040b6d1 in upstream_read_cb (bev=0x63f9c0, arg=0x63fd30) at src/network.cc:303
#4  0x00007ffff7bb0c4a in ?? () from /usr/lib/libevent-2.0.so.5
#5  0x00007ffff7ba6254 in event_base_loop () from /usr/lib/libevent-2.0.so.5
#6  0x00000000004056f3 in main (argv=0x7fffffffdef8) at src/main.cc:417

I tried running the "chop" mode but didn't figure out the usage. I seems
I need a "down_address" but I don't know what to put there.

$ ./stegotorus chop socks 127.0.0.1:5000
[warn] chop: not enough parameters
[warn] chop syntax:
        chop <mode> <up_address> (<down_address> [<steg>])...
                mode ~ server|client|socks
                up_address, down_address ~ host:port
                A steganographer is required for each down_address.
                The down_address list is still required in socks mode.
Examples:
        stegotorus chop client 127.0.0.1:5000 192.168.1.99:11253 http 192.168.1.99:11254 skype
        stegotorus chop server 127.0.0.1:9005 192.168.1.99:11253 http 192.168.1.99:11254 skype

David Fifield