examples

gvisor-exec examples

Five self-contained scripts that demonstrate how gvisor-exec behaves on real workloads. Each script is runnable on its own; run-all.sh runs the full sequence.

Prerequisites

• gvisor-exec binary built at the repo root (make build) or installed on PATH.
• runsc on PATH.
• gcc, python3, curl, tar (the scripts skip themselves with a note when an optional tool is missing).

Running

# one-shot:
./examples/run-all.sh

# or individually:
./examples/01-untrusted-script.sh
./examples/02-python-eval.sh
./examples/03-compile-ephemeral.sh
./examples/04-compile-extract.sh
./examples/05-inspect-sandbox.sh

From the repo root: make examples.

What each one shows

Script	Demonstrates
01-untrusted-script.sh	A destructive shell script piped via stdin can't rm /etc and can't reach the network. Host /etc is unchanged before and after.
02-python-eval.sh	Python code from stdin runs normally; network calls fail; writes to /tmp succeed but vanish at exit.
03-compile-ephemeral.sh	A C source directory bind-mounted into the sandbox compiles + runs, but the host directory is unchanged afterwards (overlay discards the build artifacts).
04-compile-extract.sh	Same as 03, but the compiled binary is tar'd to stdout and extracted on the host — the pattern for getting bytes out of an ephemeral sandbox.
05-inspect-sandbox.sh	Prints what isolation looks like from inside: spoofed 4.4.0 kernel, PID 1, zero effective capabilities, empty /sys/class/net, read-only /etc.

Expected output (abridged)

Running run-all.sh prints something like:

== 01-untrusted-script.sh
-- host /etc before: 228 entries --
hi from sketchy script
rm: cannot remove '/etc/libaudit.conf': Permission denied
rm: cannot remove '/etc/vim/vimrc.tiny': Permission denied
curl: (6) Could not resolve host: evil.example.com
exit
-- host /etc after: 228 entries --
OK

== 05-inspect-sandbox.sh
kernel:        4.4.0  (gVisor spoofs 4.4.0 regardless of host)
hostname:      gvisor-exec
pid:           1  (fresh pid namespace)
uid/gid:       0/0
caps:          0000000000000000  (expect all zeros)
visible pids:  4  (host has hundreds)
net ifaces:
/etc writable: no
OK