Special: Overriding OS needed files¶

Tracee supports eBPF CO-RE (Compile Once - Run Everywhere) technology and, because of that, it might need some information about the Linux OS it is running at. Tracee, through libbpfgo, must have access to /etc/os-release file AND either /boot/config-$(uname-r) OR /proc/config.gz files (KernelConfig API at helpers/kernel_config).

Note that, despite having this need, tracee will try to execute as CO-RE eBPF program in any environment it is executed.

OS-RELEASE¶

Tracee will show you collected information about the running Linux OS with the --log debug argument:

$ sudo ./dist/tracee --log debug --filter uid=1000 --filter pid=new --filter event=execve
{"level":"debug","ts":1670976393.7308447,"msg":"osinfo","ARCH":"x86_64","PRETTY_NAME":"\"Manjaro Linux\"","ID":"manjaro","ID_LIKE":"arch","BUILD_ID":"rolling","KERNEL_RELEASE":"5.15.81-1-MANJARO","pkg":"urfave","file":"urfave.go","line":53}
{"level":"debug","ts":1670976393.73088,"msg":"RuntimeSockets: failed to register default","socket":"containerd","error":"failed to register runtime socket stat /var/run/containerd/containerd.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670976393.730894,"msg":"RuntimeSockets: failed to register default","socket":"crio","error":"failed to register runtime socket stat /var/run/crio/crio.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670976393.7309017,"msg":"RuntimeSockets: failed to register default","socket":"podman","error":"failed to register runtime socket stat /var/run/podman/podman.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670976393.7310617,"msg":"osinfo","security_lockdown":"none","pkg":"urfave","file":"urfave.go","line":116}
{"level":"debug","ts":1670976393.733237,"msg":"BTF","bpfenv":false,"btfenv":false,"vmlinux":true,"pkg":"initialize","file":"bpfobject.go","line":40}
{"level":"debug","ts":1670976393.7332687,"msg":"BPF: using embedded BPF object","pkg":"initialize","file":"bpfobject.go","line":69}
{"level":"debug","ts":1670976393.7355402,"msg":"unpacked CO:RE bpf object file into memory","pkg":"initialize","file":"bpfobject.go","line":144}
TIME             UID    COMM             PID     TID     RET              EVENT                ARGS
21:06:35:386730  1000   gio-launch-desk  743960  743960  0                execve               pathname: /home/gg/.local/bin/gnome-terminal, argv: [gnome-terminal]
...

BUT os-release file might not exist:

Because you're running in a distribution that does not have /etc/os-release, or because you're running inside a container that does not support it, you may face the following error:

$ sudo ./dist/tracee --log debug --filter uid=1000 --filter pid=new --filter event=execve
{"level":"debug","ts":1670976530.5685039,"msg":"osinfo", "warning: os-release file could not be found","error","open /etc/os-release: no such file or directory","pkg":"urfave","file":"urfave.go","line":33}
...
TIME             UID    COMM             PID     TID     RET              EVENT                ARGS
...

End of events stream
Stats: {EventCount:1 ErrorCount:0 LostEvCount:0 LostWrCount:0 LostNtCount:0}

Note

But do note that tracee shall continue working (informing only the KERNEL_RELEASE OSInfo option).

If you need to override the underlaying Linux OS information, because you're running inside a container that already has /etc/os-release file, for example, you may create another os-release file and inform tracee by using LIBBPFGO's environment variable LIBBPFGO_OSRELEASE_FILE:

$ sudo LIBBPFGO_OSRELEASE_FILE=/etc/os-release.orig ./dist/tracee --filter uid=1000 --filter pid=new --filter event=execve

If you're running tracee inside a docker container, you can simply bind mount /etc/os-release from the host as /etc/os-release-host into the guest and inform that through the LIBBPFGO_OSRELEASE_FILE environment variable.

KCONFIG¶

Tracee needs access to kconfig file (/proc/config.gz OR /boot/config-$(uname -r)) in order to:

Check if the kernel of your running environment supports needed eBPF features
Provide kconfig variables to its eBPF counter-part (so eBPF program take decisions)

Warning

Tracee should NOT fail when it cannot find a kconfig file:

$ sudo ./dist/tracee --log debug --filter uid=1000 --filter pid=new --filter event=execve
{"level":"debug","ts":1670976875.7735798,"msg":"osinfo","VERSION":"\"20.04.5 LTS (Focal Fossa)\"","ID":"ubuntu","ID_LIKE":"debian","PRETTY_NAME":"\"Ubuntu 20.04.5 LTS\"","VERSION_ID":"\"20.04\"","VERSION_CODENAME":"focal","KERNEL_RELEASE":"5.4.0-91-generic","ARCH":"x86_64","pkg":"urfave","file":"urfave.go","line":53}
...
{"level":"warn","ts":1670976875.7762284,"msg":"KConfig: could not check enabled kconfig features","error":"could not read /boot/config-5.4.0-91-generic: stat /boot/config-5.4.0-91-generic: no such file or directory"}
{"level":"warn","ts":1670976875.7762842,"msg":"KConfig: assuming kconfig values, might have unexpected behavior"}
...
{"level":"debug","ts":1670976876.0801573,"msg":"KConfig: warning: assuming kconfig values, might have unexpected behavior","pkg":"initialization","file":"kconfig.go","line":30}
TIME             UID    COMM             PID     TID     RET              EVENT                ARGS
...

but do have in mind it is assuming some things from the host environment and its behavior might have inconsistencies.

If you are running tracee in an environment that does not have a kconfig file (nor /proc/config.gz support), it is recommended that you provide the host kconfig file location to tracee through the LIBBPFGO_KCONFIG_FILE environment variable:

$ sudo LIBBPFGO_KCONFIG_FILE=/boot/config-other -E ./dist/tracee --log debug --filter uid=1000 --filter pid=new --filter event=execve
{"level":"debug","ts":1670979362.3586345,"msg":"osinfo","VERSION_ID":"\"20.04\"","VERSION_CODENAME":"focal","KERNEL_RELEASE":"5.4.0-91-generic","ARCH":"x86_64","VERSION":"\"20.04.5 LTS (Focal Fossa)\"","ID":"ubuntu","ID_LIKE":"debian","PRETTY_NAME":"\"Ubuntu 20.04.5 LTS\"","pkg":"urfave","file":"urfave.go","line":53}
{"level":"debug","ts":1670979362.358663,"msg":"RuntimeSockets: failed to register default","socket":"containerd","error":"failed to register runtime socket stat /var/run/containerd/containerd.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670979362.3586702,"msg":"RuntimeSockets: failed to register default","socket":"docker","error":"failed to register runtime socket stat /var/run/docker.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670979362.3586755,"msg":"RuntimeSockets: failed to register default","socket":"crio","error":"failed to register runtime socket stat /var/run/crio/crio.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670979362.3586833,"msg":"RuntimeSockets: failed to register default","socket":"podman","error":"failed to register runtime socket stat /var/run/podman/podman.sock: no such file or directory","pkg":"flags","file":"containers.go","line":45}
{"level":"debug","ts":1670979362.3588264,"msg":"osinfo","security_lockdown":"none","pkg":"urfave","file":"urfave.go","line":116}
{"level":"debug","ts":1670979362.3639433,"msg":"BTF","bpfenv":false,"btfenv":false,"vmlinux":false,"pkg":"initialize","file":"bpfobject.go","line":40}
{"level":"debug","ts":1670979362.363965,"msg":"BPF: no BTF file was found or provided","pkg":"initialize","file":"bpfobject.go","line":108}
{"level":"debug","ts":1670979362.3639715,"msg":"BPF: trying non CO-RE eBPF","file":"/tmp/tracee/tracee.bpf.5_4_0-91-generic.v0_8_0-rc-2-365-g0bac8f68.o","pkg":"initialize","file":"bpfobject.go","line":109}
{"level":"debug","ts":1670979362.4866858,"msg":"Enricher","error":"error registering enricher: unsupported runtime containerd","pkg":"containers","file":"containers.go","line":64}
{"level":"debug","ts":1670979362.486713,"msg":"Enricher","error":"error registering enricher: unsupported runtime crio","pkg":"containers","file":"containers.go","line":68}
{"level":"debug","ts":1670979362.486717,"msg":"Enricher","error":"error registering enricher: unsupported runtime docker","pkg":"containers","file":"containers.go","line":72}
TIME             UID    COMM             PID     TID     RET              EVENT                ARGS
...

If you're running tracee inside a docker container, you can simply bind mount /boot/config-$(uname -r) from the host as /boot/config-$(uname -r) into the guest and inform that through the LIBBPFGO_KCONFIG_FILE environment variable.

Attention

In case no kconfig file is found, tracee takes some decisions blindly and it may give you unexpected errors. Example: