tests: add functional tests for seccomp notify

Add functional test to check seccomp notify end-to-end. This test uses the
sample seccomp agent from the contrib/cmd folder.

Signed-off-by: Mauricio Vásquez <[email protected]>
Signed-off-by: Rodrigo Campos <[email protected]>
Co-authored-by: Rodrigo Campos <[email protected]>

tests/integration/helpers.bash

@@ -17,6 +17,7 @@ unset IMAGES
 RUNC="${INTEGRATION_ROOT}/../../runc"
 RECVTTY="${INTEGRATION_ROOT}/../../contrib/cmd/recvtty/recvtty"
 SD_HELPER="${INTEGRATION_ROOT}/../../contrib/cmd/sd-helper/sd-helper"
+SECCOMP_AGENT="${INTEGRATION_ROOT}/../../contrib/cmd/seccompagent/seccompagent"
 
 # Test data path.
 # shellcheck disable=SC2034
@@ -31,6 +32,11 @@ KERNEL_MAJOR="${KERNEL_VERSION%%.*}"
 KERNEL_MINOR="${KERNEL_VERSION#$KERNEL_MAJOR.}"
 KERNEL_MINOR="${KERNEL_MINOR%%.*}"
 
+ARCH=$(uname -m)
+
+# Seccomp agent socket.
+SECCCOMP_AGENT_SOCKET="$BATS_TMPDIR/seccomp-agent.sock"
+
 # Check if we're in rootless mode.
 ROOTLESS=$(id -u)
 
@@ -428,6 +434,11 @@ function requires() {
  skip_me=1
  fi
  ;;
+ arch_x86_64)
+ if [ "$ARCH" != "x86_64" ]; then
+ skip_me=1
+ fi
+ ;;
  *)
  fail "BUG: Invalid requires $var."
  ;;
@@ -505,6 +516,18 @@ function teardown_recvtty() {
  rm -rf "$dir"
 }
 
+function setup_seccompagent() {
+ ("${SECCOMP_AGENT}" -socketfile="$SECCCOMP_AGENT_SOCKET" -pid-file "$BATS_TMPDIR/seccompagent.pid" &) &
+}
+
+function teardown_seccompagent() {
+ if [ -f "$BATS_TMPDIR/seccompagent.pid" ]; then
+ kill -9 "$(cat "$BATS_TMPDIR/seccompagent.pid")"
+ fi
+ rm -f "$BATS_TMPDIR/seccompagent.pid"
+ rm -f "$SECCCOMP_AGENT_SOCKET"
+}
+
 function setup_bundle() {
  local image="$1"
 
@@ -545,3 +568,12 @@ function teardown_bundle() {
  rm -rf "$ROOT"
  remove_parent
 }
+
+function requires_kernel() {
+ local major_required minor_required
+ major_required=$(echo "$1" | cut -d. -f1)
+ minor_required=$(echo "$1" | cut -d. -f2)
+ if [[ "$KERNEL_MAJOR" -lt $major_required || ("$KERNEL_MAJOR" -eq $major_required && "$KERNEL_MINOR" -lt $minor_required) ]]; then
+ skip "requires kernel $1"
+ fi
+}

tests/integration/seccomp-notify-compat.bats

@@ -0,0 +1,35 @@
+#!/usr/bin/env bats
+
+load helpers
+
+function setup() {
+ if [[ "$KERNEL_MAJOR" -gt 5 || ("$KERNEL_MAJOR" -eq 5 && "$KERNEL_MINOR" -ge 6) ]]; then
+ skip "requires kernel less than 5.6"
+ fi
+
+ requires arch_x86_64
+
+ setup_seccompagent
+ setup_busybox
+}
+
+function teardown() {
+ teardown_seccompagent
+ teardown_bundle
+}
+
+# Support for seccomp notify requires Linux > 5.6, check that on older kernels
+# return an error.
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY old kernel)" {
+ # Use just any seccomp profile with a notify action.
+ update_config ' .linux.seccomp = {
+ "defaultAction": "SCMP_ACT_ALLOW",
+ "listenerPath": "'"$SECCCOMP_AGENT_SOCKET"'",
+ "architectures": [ "SCMP_ARCH_X86","SCMP_ARCH_X32", "SCMP_ARCH_X86_64" ],
+ "syscalls": [{ "names": [ "mkdir" ], "action": "SCMP_ACT_NOTIFY" }]
+ }'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+ [[ "$output" == *"seccomp notify unsupported:"* ]]
+}

tests/integration/seccomp-notify.bats

@@ -0,0 +1,200 @@
+#!/usr/bin/env bats
+
+load helpers
+
+# Support for seccomp notify requires Linux > 5.6 because
+# runc uses the pidfd_getfd system call to fetch the seccomp fd.
+# https://github.com/torvalds/linux/commit/8649c322f75c96e7ced2fec201e123b2b073bf09
+# We also require arch x86_64, to not make this fail when people run tests
+# locally on other archs.
+function setup() {
+ requires_kernel 5.6
+ requires arch_x86_64
+
+ setup_seccompagent
+ setup_busybox
+}
+
+function teardown() {
+ teardown_seccompagent
+ teardown_bundle
+}
+
+# Create config.json template with SCMP_ACT_NOTIFY actions
+# $1: command to run
+# $2: noNewPrivileges (false/true)
+# $3: list of syscalls
+function scmp_act_notify_template() {
+ # The agent intercepts mkdir syscalls and creates the folder appending
+ # "-bar" (listenerMetadata below) to the name.
+ update_config ' .process.args = ["/bin/sh", "-c", "'"$1"'"]
+ | .process.noNewPrivileges = '"$2"'
+ | .linux.seccomp = {
+ "defaultAction":"SCMP_ACT_ALLOW",
+ "listenerPath": "'"$SECCCOMP_AGENT_SOCKET"'",
+ "listenerMetadata": "bar",
+ "architectures": [ "SCMP_ARCH_X86","SCMP_ARCH_X32", "SCMP_ARCH_X86_64" ],
+ "syscalls": [{ "names": ['"$3"'], "action": "SCMP_ACT_NOTIFY" }]
+ }'
+}
+
+# The call to seccomp is done at different places according to the value of
+# noNewPrivileges, for this reason many of the following cases are tested with
+# both values.
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY noNewPrivileges false)" {
+ scmp_act_notify_template "mkdir /dev/shm/foo && stat /dev/shm/foo-bar" false '"mkdir"'
+
+ runc run test_busybox
+ [ "$status" -eq 0 ]
+}
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY noNewPrivileges true)" {
+ scmp_act_notify_template "mkdir /dev/shm/foo && stat /dev/shm/foo-bar" true '"mkdir"'
+
+ runc run test_busybox
+ [ "$status" -eq 0 ]
+}
+
+@test "runc exec [seccomp] (SCMP_ACT_NOTIFY noNewPrivileges false)" {
+ requires root
+
+ scmp_act_notify_template "sleep infinity" false '"mkdir"'
+
+ runc run -d --console-socket "$CONSOLE_SOCKET" test_busybox
+ [ "$status" -eq 0 ]
+
+ runc exec test_busybox /bin/sh -c "mkdir /dev/shm/foo && stat /dev/shm/foo-bar"
+ [ "$status" -eq 0 ]
+}
+
+@test "runc exec [seccomp] (SCMP_ACT_NOTIFY noNewPrivileges true)" {
+ requires root
+
+ scmp_act_notify_template "sleep infinity" true '"mkdir"'
+
+ runc run -d --console-socket "$CONSOLE_SOCKET" test_busybox
+ runc exec test_busybox /bin/sh -c "mkdir /dev/shm/foo && stat /dev/shm/foo-bar"
+ [ "$status" -eq 0 ]
+}
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY important syscalls noNewPrivileges false)" {
+ scmp_act_notify_template "/bin/true" false '"execve","openat","open","read","close"'
+
+ runc run test_busybox
+ [ "$status" -eq 0 ]
+}
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY important syscalls noNewPrivileges true)" {
+ scmp_act_notify_template "/bin/true" true '"execve","openat","open","read","close"'
+
+ runc run test_busybox
+ [ "$status" -eq 0 ]
+}
+
+@test "runc run [seccomp] (empty listener path)" {
+ update_config ' .process.args = ["/bin/sh", "-c", "mkdir /dev/shm/foo && stat /dev/shm/foo"]
+ | .linux.seccomp = {
+ "defaultAction":"SCMP_ACT_ALLOW",
+ "listenerPath": "'"$SECCCOMP_AGENT_SOCKET"'",
+ "listenerMetadata": "bar",
+ }'
+
+ runc run test_busybox
+ [ "$status" -eq 0 ]
+}
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY empty listener path)" {
+ scmp_act_notify_template "/bin/true" false '"mkdir"'
+ update_config '.linux.seccomp.listenerPath = ""'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+}
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY wrong listener path)" {
+ scmp_act_notify_template "/bin/true" false '"mkdir"'
+ update_config '.linux.seccomp.listenerPath = "/some-non-existing-listener-path.sock"'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+}
+
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY abstract listener path)" {
+ scmp_act_notify_template "/bin/true" false '"mkdir"'
+ update_config '.linux.seccomp.listenerPath = "@mysocketishere"'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+}
+
+# Check that killing the seccompagent doesn't block syscalls in
+# the container. They should return ENOSYS instead.
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY kill seccompagent)" {
+ scmp_act_notify_template "sleep 4 && mkdir /dev/shm/foo" false '"mkdir"'
+
+ sleep 2 && teardown_seccompagent &
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+ [[ "$output" == *"mkdir:"*"/dev/shm/foo"*"Function not implemented"* ]]
+}
+
+# Check that starting with no seccomp agent running fails with a clear error.
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY no seccompagent)" {
+ teardown_seccompagent
+
+ scmp_act_notify_template "/bin/true" false '"mkdir"'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+ [[ "$output" == *"failed to connect with seccomp agent"* ]]
+}
+
+# Check that agent-returned error for the syscall works.
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY error chmod)" {
+ scmp_act_notify_template "touch /dev/shm/foo && chmod 777 /dev/shm/foo" false '"chmod", "fchmod", "fchmodat"'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+ [[ "$output" == *"chmod:"*"/dev/shm/foo"*"No medium found"* ]]
+}
+
+# check that trying to use SCMP_ACT_NOTIFY with write() gives a meaningful error.
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY write)" {
+ scmp_act_notify_template "/bin/true" false '"write"'
+
+ runc run test_busybox
+ [ "$status" -ne 0 ]
+ [[ "$output" == *"SCMP_ACT_NOTIFY cannot be used for the write syscall"* ]]
+}
+
+# check that a startContainer hook doesn't get any extra file descriptor.
+@test "runc run [seccomp] (SCMP_ACT_NOTIFY startContainer hook)" {
+ # shellcheck disable=SC2016
+ # We use single quotes to properly delimit the $1 param to
+ # update_config(), but this shellshcheck is quite silly and fails if the
+ # multi-line string includes some $var (even when it is properly outside of the
+ # single quotes) or when we use this syntax to execute commands in the
+ # string: $(command).
+ # So, just disable this check for our usage of update_config().
+ update_config ' .process.args = ["/bin/true"]
+ | .linux.seccomp = {
+ "defaultAction":"SCMP_ACT_ALLOW",
+ "listenerPath": "'"$SECCCOMP_AGENT_SOCKET"'",
+ "architectures": [ "SCMP_ARCH_X86", "SCMP_ARCH_X32", "SCMP_ARCH_X86_64" ],
+ "syscalls":[{ "names": [ "mkdir" ], "action": "SCMP_ACT_NOTIFY" }]
+ }
+ |.hooks = {
+ "startContainer": [ {
+ "path": "/bin/sh",
+ "args": [
+ "sh",
+ "-c",
+ "if [ $(ls /proc/self/fd/ | wc -l) -ne 4 ]; then echo \"File descriptors is not 4\". && ls /proc/self/fd/ | wc -l && exit 1; fi"
+ ],
+ } ]
+ }'
+
+ runc run test_busybox
+ [ "$status" -eq 0 ]
+}