[PATCH net-next v2 5/6] selftests/vsock: test the guest vsock device network namespace

[Bobby Eshleman]

From: Bobby Eshleman <bobbyeshleman@xxxxxxxx>

Add tests for guest vsock device namespace assignment, including ns
destruction and the device moving between namespaces.

We do add ynl/cli.py, so have added python3 and PyYAML to the dependency
checks.

Signed-off-by: Bobby Eshleman <bobbyeshleman@xxxxxxxx>
---
Changes in v2:
- Drive the assign with ynl cli.py, drop the vsock_assign_g2h_netns
  ioctl helper and its patch
- Terminate the guest socat sender too, it sometimes outlived the test
  and kept holding on to a port the next test binds
---
 tools/testing/selftests/vsock/vmtest.sh | 421 +++++++++++++++++++++++++++++++-
 1 file changed, 416 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
index 310dfc2a39ad..e94cc2fd90cc 100755
--- a/tools/testing/selftests/vsock/vmtest.sh
+++ b/tools/testing/selftests/vsock/vmtest.sh
@@ -17,6 +17,8 @@ readonly KERNEL_CHECKOUT=$(realpath "${SCRIPT_DIR}"/../../../../)
 source "${SCRIPT_DIR}"/../kselftest/ktap_helpers.sh
 
 readonly VSOCK_TEST="${SCRIPT_DIR}"/vsock_test
+readonly YNL_CLI="${KERNEL_CHECKOUT}"/tools/net/ynl/pyynl/cli.py
+readonly VSOCK_SPEC="${KERNEL_CHECKOUT}"/Documentation/netlink/specs/vsock.yaml
 readonly TEST_GUEST_PORT=51000
 readonly TEST_HOST_PORT=50000
 readonly TEST_HOST_PORT_LISTENER=50001
@@ -73,6 +75,12 @@ readonly TEST_NAMES=(
 	ns_delete_vm_ok
 	ns_delete_host_ok
 	ns_delete_both_ok
+	ns_guest_local_connect_to_host_fails
+	ns_guest_assign_g2h_netns_connect_to_host_ok
+	ns_guest_assign_g2h_netns_init_ns_connect_fails
+	ns_guest_assign_g2h_netns_host_connect_ok
+	ns_guest_assign_g2h_netns_reset_on_ns_delete_ok
+	ns_guest_assign_g2h_netns_old_conn_send_fails
 )
 readonly TEST_DESCS=(
 	# vm_server_host_client
@@ -149,12 +157,36 @@ readonly TEST_DESCS=(
 
 	# ns_delete_both_ok
 	"Check that deleting the VM and host's namespaces does not break the socket connection"
+
+	# ns_guest_local_connect_to_host_fails
+	"Check a guest process in a local ns cannot reach the host without the netns assign."
+
+	# ns_guest_assign_g2h_netns_connect_to_host_ok
+	"Check a guest process in a local ns reaches the host once the vsock device is assigned to it."
+
+	# ns_guest_assign_g2h_netns_init_ns_connect_fails
+	"Check the guest's initial ns loses vsock once the device is assigned to another ns."
+
+	# ns_guest_assign_g2h_netns_host_connect_ok
+	"Check the host reaches a guest listener in the ns the vsock device is assigned to."
+
+	# ns_guest_assign_g2h_netns_reset_on_ns_delete_ok
+	"Check the guest's vsock device returns to the initial ns when its ns is deleted."
+
+	# ns_guest_assign_g2h_netns_old_conn_send_fails
+	"Check connections made before the assign stop sending once they lose the device."
 )
 
 readonly USE_SHARED_VM=(
 	vm_server_host_client
 	vm_client_host_server
 	vm_loopback
+	ns_guest_local_connect_to_host_fails
+	ns_guest_assign_g2h_netns_connect_to_host_ok
+	ns_guest_assign_g2h_netns_init_ns_connect_fails
+	ns_guest_assign_g2h_netns_host_connect_ok
+	ns_guest_assign_g2h_netns_reset_on_ns_delete_ok
+	ns_guest_assign_g2h_netns_old_conn_send_fails
 )
 readonly NS_MODES=("local" "global")
 
@@ -302,7 +334,8 @@ check_args() {
 }
 
 check_deps() {
-	for dep in vng ${QEMU} busybox pkill ssh ss socat nsenter; do
+	for dep in vng ${QEMU} busybox pkill ssh ss socat nsenter unshare \
+		python3; do
 		if [[ ! -x $(command -v "${dep}") ]]; then
 			echo -e "skip:    dependency ${dep} not found!\n"
 			exit "${KSFT_SKIP}"
@@ -314,6 +347,18 @@ check_deps() {
 		printf " Please build the kselftest vsock target.\n"
 		exit "${KSFT_SKIP}"
 	fi
+
+	if ! python3 -c "import yaml" &>/dev/null; then
+		echo -e "skip:    python3 yaml module not found!\n"
+		exit "${KSFT_SKIP}"
+	fi
+
+	for dep in "${YNL_CLI}" "${VSOCK_SPEC}"; do
+		if [[ ! -r "${dep}" ]]; then
+			printf "skip:    %s not found!\n" "${dep}"
+			exit "${KSFT_SKIP}"
+		fi
+	done
 }
 
 check_netns() {
@@ -401,6 +446,17 @@ setup_home() {
 	mkdir -p "$(dirname "${SSH_KEY_PATH}")"
 	ssh-keygen -t ed25519 -f "${SSH_KEY_PATH}" -N "" -q
 	cp "${VSOCK_TEST}" "${TEST_HOME}"/vsock_test
+
+	mkdir -p "${TEST_HOME}"/ynl
+	cp "${YNL_CLI}" "${TEST_HOME}"/ynl/
+	cp -r "$(dirname "${YNL_CLI}")"/lib "${TEST_HOME}"/ynl/
+	cp "${VSOCK_SPEC}" "${TEST_HOME}"/ynl/
+
+	# One of the tests runs the CLI as an unprivileged user, so the CLI
+	# has to be reachable by one.
+	chmod -R a+rX "${TEST_HOME}"/ynl
+
+	chmod 755 "${TEST_HOME}"
 }
 
 create_pidfile() {
@@ -528,6 +584,59 @@ vm_wait_for_ssh() {
 	done
 }
 
+# Create a local mode namespace in the VM and echo the pid holding it open.
+vm_ns_start() {
+	local ns=$1
+
+	vm_ssh "${ns}" -- \
+		"echo local > /proc/sys/net/vsock/child_ns_mode" &>/dev/null
+
+	vm_ssh "${ns}" -- "unshare -n sleep infinity" \
+		'>/dev/null 2>&1 & echo $!'
+}
+
+# Returns once the holder is gone, so that the namespace is unreferenced and
+# the kernel can start tearing it down.
+vm_ns_stop() {
+	local ns=$1
+	local nspid=$2
+
+	vm_ssh "${ns}" <<-EOF &>/dev/null
+		kill ${nspid}
+		for ((i = 0; i < ${WAIT_PERIOD_MAX}; i++)); do
+			kill -0 ${nspid} 2>/dev/null || break
+			sleep 1
+		done
+	EOF
+}
+
+# Runs in the guest's initial namespace when <nspid> is empty. The command must
+# not contain single quotes.
+vm_ns_exec() {
+	local ns=$1
+	local nspid=$2
+	local cmd=$3
+
+	if [[ -z "${nspid}" ]]; then
+		vm_ssh "${ns}" -- "${cmd}"
+		return
+	fi
+
+	vm_ssh "${ns}" -- nsenter -t "${nspid}" -n sh -c "'${cmd}'"
+}
+
+vm_ns_assign_g2h() {
+	local ns=$1
+	local nspid=$2
+
+	vm_ns_exec "${ns}" "${nspid}" "python3 /root/ynl/cli.py --no-schema \
+		--spec /root/ynl/vsock.yaml --do dev-netns-set"
+}
+
+vm_reset_g2h() {
+	vm_ns_assign_g2h "init_ns" "" &>/dev/null
+}
+
 # derived from selftests/net/net_helper.sh
 wait_for_listener()
 {
@@ -564,17 +673,33 @@ wait_for_listener()
 	done
 }
 
-vm_wait_for_listener() {
+# Runs in the guest's initial namespace when <nspid> is empty.
+vm_ns_wait_for_listener() {
 	local ns=$1
-	local port=$2
-	local protocol=$3
+	local nspid=$2
+	local port=$3
+	local protocol=$4
+	local nsenter=
+	local args
+
+	[[ -n "${nspid}" ]] && nsenter="nsenter -t ${nspid} -n"
+	args="${port} ${WAIT_PERIOD} ${WAIT_PERIOD_MAX} ${protocol}"
 
 	vm_ssh "${ns}" <<EOF
 $(declare -f wait_for_listener)
-wait_for_listener ${port} ${WAIT_PERIOD} ${WAIT_PERIOD_MAX} ${protocol}
+export -f wait_for_listener
+${nsenter} bash -c "wait_for_listener ${args}"
 EOF
 }
 
+vm_wait_for_listener() {
+	local ns=$1
+	local port=$2
+	local protocol=$3
+
+	vm_ns_wait_for_listener "${ns}" "" "${port}" "${protocol}"
+}
+
 host_wait_for_listener() {
 	local ns=$1
 	local port=$2
@@ -1421,6 +1546,292 @@ test_ns_delete_both_ok() {
 	check_ns_delete_doesnt_break_connection "both"
 }
 
+# Send a string from the guest to a host listener and leave what the host
+# received in <outfile>.
+guest_send_to_host() {
+	local ns=$1
+	local nspid=$2
+	local port=$3
+	local outfile=$4
+	local cmd="echo TEST | socat -u STDIN VSOCK-CONNECT:2:${port}"
+	local pid
+
+	socat -u VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" 2>/dev/null &
+	pid=$!
+	host_wait_for_listener "${ns}" "${port}" "vsock"
+
+	vm_ns_exec "${ns}" "${nspid}" "${cmd}" 2>/dev/null
+
+	timeout "${WAIT_PERIOD}" \
+		bash -c 'while [[ ! -s '"${outfile}"' ]]; do sleep 1; done'
+
+	terminate_pids "${pid}"
+}
+
+# Send a string from the host to a listener in the guest and leave what the
+# guest received in <outfile>.
+host_send_to_guest() {
+	local ns=$1
+	local nspid=$2
+	local port=$3
+	local outfile=$4
+	local cmd="socat -u VSOCK-LISTEN:${port} STDOUT"
+	local dst="VSOCK-CONNECT:${VSOCK_CID}:${port}"
+	local pid
+
+	vm_ns_exec "${ns}" "${nspid}" "${cmd}" > "${outfile}" 2>/dev/null &
+	pid=$!
+	vm_ns_wait_for_listener "${ns}" "${nspid}" "${port}" "vsock"
+
+	echo TEST | socat -u STDIN "${dst}" 2>/dev/null
+
+	timeout "${WAIT_PERIOD}" \
+		bash -c 'while [[ ! -s '"${outfile}"' ]]; do sleep 1; done'
+
+	terminate_pids "${pid}"
+}
+
+test_ns_guest_assign_g2h_netns_old_conn_send_fails() {
+	local gap=$(( WAIT_PERIOD * 3 ))
+	local port=12346
+	local outfile
+	local result
+	local sender
+	local nspid
+	local pid
+
+	nspid=$(vm_ns_start "init_ns")
+	if [[ -z "${nspid}" ]]; then
+		log_host "failed to create a namespace inside the guest"
+		return "${KSFT_FAIL}"
+	fi
+
+	outfile=$(mktemp)
+	socat -u VSOCK-LISTEN:"${port}" STDOUT > "${outfile}" 2>/dev/null &
+	pid=$!
+	host_wait_for_listener "init_ns" "${port}" "vsock"
+
+	# Send a message, wait, then send another. While waiting, assign the
+	# device to a namespace. Confirm the second message does not arrive.
+	vm_ssh "init_ns" -- \
+		"(echo FIRST; sleep ${gap}; echo SECOND) |" \
+		"socat -u STDIN VSOCK-CONNECT:2:${port}" &>/dev/null &
+	sender=$!
+
+	sleep "${WAIT_PERIOD}"
+
+	if ! vm_ns_assign_g2h "init_ns" "${nspid}"; then
+		log_host "failed to assign the vsock device to the guest ns"
+		terminate_pids "${pid}" "${sender}"
+		rm -f "${outfile}"
+		vm_ns_stop "init_ns" "${nspid}"
+		vm_reset_g2h
+		return "${KSFT_FAIL}"
+	fi
+
+	# Let the second write happen and land, if it is going to.
+	sleep $(( gap + WAIT_PERIOD ))
+
+	terminate_pids "${pid}" "${sender}"
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	vm_ns_stop "init_ns" "${nspid}"
+	vm_reset_g2h
+
+	if [[ "${result}" != *FIRST* ]]; then
+		log_host "no connection before the assign: [${result}]"
+		return "${KSFT_FAIL}"
+	fi
+
+	if [[ "${result}" == *SECOND* ]]; then
+		log_host "old connection still delivered after the assign"
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_guest_local_connect_to_host_fails() {
+	local port=12345
+	local outfile
+	local result
+	local nspid
+
+	nspid=$(vm_ns_start "init_ns")
+	if [[ -z "${nspid}" ]]; then
+		log_host "failed to create a namespace inside the guest"
+		return "${KSFT_FAIL}"
+	fi
+
+	outfile=$(mktemp)
+	guest_send_to_host "init_ns" "${nspid}" "${port}" "${outfile}"
+
+	vm_ns_stop "init_ns" "${nspid}"
+	vm_reset_g2h
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" == TEST ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_guest_assign_g2h_netns_connect_to_host_ok() {
+	local port=12345
+	local outfile
+	local result
+	local nspid
+
+	nspid=$(vm_ns_start "init_ns")
+	if [[ -z "${nspid}" ]]; then
+		log_host "failed to create a namespace inside the guest"
+		return "${KSFT_FAIL}"
+	fi
+
+	if ! vm_ns_assign_g2h "init_ns" "${nspid}"; then
+		log_host "failed to assign the vsock device to the guest ns"
+		vm_ns_stop "init_ns" "${nspid}"
+		vm_reset_g2h
+		return "${KSFT_FAIL}"
+	fi
+
+	outfile=$(mktemp)
+	guest_send_to_host "init_ns" "${nspid}" "${port}" "${outfile}"
+
+	vm_ns_stop "init_ns" "${nspid}"
+	vm_reset_g2h
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" != TEST ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_guest_assign_g2h_netns_init_ns_connect_fails() {
+	local port=12345
+	local outfile
+	local result
+	local nspid
+
+	nspid=$(vm_ns_start "init_ns")
+	if [[ -z "${nspid}" ]]; then
+		log_host "failed to create a namespace inside the guest"
+		return "${KSFT_FAIL}"
+	fi
+
+	if ! vm_ns_assign_g2h "init_ns" "${nspid}"; then
+		log_host "failed to assign the vsock device to the guest ns"
+		vm_ns_stop "init_ns" "${nspid}"
+		vm_reset_g2h
+		return "${KSFT_FAIL}"
+	fi
+
+	# The device now belongs to a local-mode namespace, so the guest's
+	# initial namespace must no longer reach the host.
+	outfile=$(mktemp)
+	guest_send_to_host "init_ns" "" "${port}" "${outfile}"
+
+	vm_ns_stop "init_ns" "${nspid}"
+	vm_reset_g2h
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" == TEST ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_guest_assign_g2h_netns_host_connect_ok() {
+	local port=12345
+	local outfile
+	local result
+	local nspid
+
+	nspid=$(vm_ns_start "init_ns")
+	if [[ -z "${nspid}" ]]; then
+		log_host "failed to create a namespace inside the guest"
+		return "${KSFT_FAIL}"
+	fi
+
+	if ! vm_ns_assign_g2h "init_ns" "${nspid}"; then
+		log_host "failed to assign the vsock device to the guest ns"
+		vm_ns_stop "init_ns" "${nspid}"
+		vm_reset_g2h
+		return "${KSFT_FAIL}"
+	fi
+
+	outfile=$(mktemp)
+	host_send_to_guest "init_ns" "${nspid}" "${port}" "${outfile}"
+
+	vm_ns_stop "init_ns" "${nspid}"
+	vm_reset_g2h
+
+	result=$(cat "${outfile}")
+	rm -f "${outfile}"
+
+	if [[ "${result}" != TEST ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
+test_ns_guest_assign_g2h_netns_reset_on_ns_delete_ok() {
+	local port=12345
+	local outfile
+	local result
+	local nspid
+	local i
+
+	nspid=$(vm_ns_start "init_ns")
+	if [[ -z "${nspid}" ]]; then
+		log_host "failed to create a namespace inside the guest"
+		return "${KSFT_FAIL}"
+	fi
+
+	if ! vm_ns_assign_g2h "init_ns" "${nspid}"; then
+		log_host "failed to assign the vsock device to the guest ns"
+		vm_ns_stop "init_ns" "${nspid}"
+		vm_reset_g2h
+		return "${KSFT_FAIL}"
+	fi
+
+	vm_ns_stop "init_ns" "${nspid}"
+
+	# The holder is gone, but the namespace itself is dismantled from a
+	# workqueue, so the device does not come back the same instant. Retry
+	# until it does, rather than expecting the first send to succeed.
+	outfile=$(mktemp)
+	for ((i = 0; i < 5; i++)); do
+		sleep "${WAIT_PERIOD}"
+		guest_send_to_host "init_ns" "" "$(( port + i ))" "${outfile}"
+		result=$(cat "${outfile}")
+		if [[ "${result}" == TEST ]]; then
+			break
+		fi
+	done
+
+	rm -f "${outfile}"
+	vm_reset_g2h
+
+	if [[ "${result}" != TEST ]]; then
+		return "${KSFT_FAIL}"
+	fi
+
+	return "${KSFT_PASS}"
+}
+
 shared_vm_test() {
 	local tname
 

-- 
2.53.0-Meta