- Fixed reloading process monitor method if the configuration changes on
disk. This can occur in two situations: 1) if it's changed from the
UI, 2) if the user changes it manually.
- Ensure that we don't crash if there's an error changing the
method and ebpf is active.
- When changing monitor method to ebpf and it fails to start, stop it
anyway. It helps cleaning up kprobes and avoiding the error
"cannot write...: file exists".
* Use ebpf program to find PID of new connections.
before running the branch you have to compile ebpf_prog/opensnitch.c
opensnitch.c is an eBPF program. Compilation requires getting kernel source.
cd opensnitch
wget https://github.com/torvalds/linux/archive/v5.8.tar.gz
tar -xf v5.8.tar.gz
patch linux-5.8/tools/lib/bpf/bpf_helpers.h < ebpf_prog/file.patch
cp ebpf_prog/opensnitch.c ebpf_prog/Makefile linux-5.8/samples/bpf
cd linux-5.8 && yes "" | make oldconfig && make prepare && make headers_install # (1 min)
cd samples/bpf && make
objdump -h opensnitch.o #you should see many section, number 1 should be called kprobe/tcp_v4_connect
llvm-strip -g opensnitch.o #remove debug info
sudo cp opensnitch.o /etc/opensnitchd
cd ../../../daemon
--opensnitchd expects to find opensnitch.o in /etc/opensnitchd/
--start opensnitchd with:
opensnitchd -rules-path /etc/opensnitchd/rules -process-monitor-method ebpf
Co-authored-by: themighty1 <you@example.com>
Co-authored-by: Gustavo Iñiguez Goia <gooffy1@gmail.com>
Use auditd events to keep a list of PIDs which open sockets, reading
them from the audisp af_unix plugin.
- Install auditd and audisp-plugins
- Enable the af_unix plugin (/etc/audisp-plugin/af_unix, active = yes)
- Start opensnitch with -process-monitor-method audit.
If the choosen method is audit but it's not active or not installed,
it'll fallback to /proc anyway.
If it's properly configured, a debug trace will be written to the logs:
"PID found via audit events ..."
Until now OpenSnitch used ftrace(debugfs) to search for running
processes (PIDs) and obtain the process path.
On some systems, this filesystem is not mounted or available, so we have
to rely on /proc.
After several weeks of use, I think that it's faster and more accurate
the 2nd method, search pids/cmdlines in /proc. So we offer the user to
choose which one to use.
