open-nomad/client/fingerprint/bridge_linux_test.go
Seth Hoenig 9960f96446 client/fingerprint: detect unloaded dynamic bridge kernel module
In Nomad v0.12.0, the client added additional fingerprinting around the
presense of the bridge kernel module. The fingerprinter only checked in
`/proc/modules` which is a list of loaded modules. In some cases, the
bridge kernel module is builtin rather than dynamically loaded. The fix
for that case is in #8721. However we were still missing the case where
the bridge module is dynamically loaded, but not yet loaded during the
startup of the Nomad agent. In this case the fingerprinter would believe
the bridge module was unavailable when really it gets loaded on demand.

This PR now has the fingerprinter scan the kernel module dependency file,
which will contain an entry for the bridge module even if it is not yet
loaded.

In summary, the client now looks for the bridge kernel module in
 - /proc/modules
 - /lib/modules/<kernel>/modules.builtin
 - /lib/modules/<kernel>/modules.dep

Closes #8423
2020-11-09 13:56:14 -06:00

130 lines
3.7 KiB
Go

package fingerprint
import (
"fmt"
"io"
"io/ioutil"
"os"
"strings"
"testing"
"github.com/hashicorp/nomad/helper/testlog"
"github.com/stretchr/testify/require"
)
func TestBridgeFingerprint_detect(t *testing.T) {
f := &BridgeFingerprint{logger: testlog.HCLogger(t)}
require.NoError(t, f.detect("ip_tables"))
err := f.detect("nonexistentmodule")
require.Error(t, err)
require.Contains(t, err.Error(), "3 errors occurred")
}
func writeFile(t *testing.T, prefix, content string) string {
f, err := ioutil.TempFile("", "bridge-fp-")
require.NoError(t, err)
_, err = io.Copy(f, strings.NewReader(content))
require.NoError(t, err)
err = f.Close()
require.NoError(t, err)
return f.Name()
}
func cleanupFile(t *testing.T, name string) {
err := os.Remove(name)
require.NoError(t, err)
}
const (
dynamicModuleContent = `
ip_tables 32768 0 - Live 0xffffffffc03ee000
x_tables 40960 1 ip_tables, Live 0xffffffffc03e3000
autofs4 45056 2 - Live 0xffffffffc03d7000
bpfilter 32768 0 - Live 0x0000000000000000
br_netfilter 28672 0 - Live 0x0000000000000000
bridge 176128 1 br_netfilter, Live 0x0000000000000000
btrfs 1253376 0 - Live 0xffffffffc02a4000
`
builtinModuleContent = `
kernel/drivers/mfd/max14577.ko
kernel/drivers/mfd/max77693.ko
kernel/drivers/mfd/sec-core.ko
kernel/drivers/mfd/sec-irq.ko
kernel/drivers/net/bridge.ko
kernel/drivers/net/tun.ko
kernel/drivers/net/xen-netfront.k
`
dependsModuleContent = `
kernel/net/bridge/netfilter/ebt_log.ko: kernel/net/netfilter/x_tables.ko
kernel/net/bridge/netfilter/ebt_nflog.ko: kernel/net/netfilter/x_tables.ko
kernel/net/bridge/bridge.ko: kernel/net/802/stp.ko kernel/net/llc/llc.ko
kernel/net/bridge/br_netfilter.ko: kernel/net/bridge/bridge.ko kernel/net/802/stp.ko kernel/net/llc/llc.ko
kernel/net/appletalk/appletalk.ko: kernel/net/802/psnap.ko kernel/net/llc/llc.ko
kernel/net/x25/x25.ko:
`
)
func TestBridgeFingerprint_search(t *testing.T) {
f := &BridgeFingerprint{logger: testlog.HCLogger(t)}
t.Run("dynamic loaded module", func(t *testing.T) {
t.Run("present", func(t *testing.T) {
file := writeFile(t, "bridge-fp-", dynamicModuleContent)
defer cleanupFile(t, file)
err := f.searchFile("bridge", file, f.regexp(dynamicModuleRe, "bridge"))
require.NoError(t, err)
})
t.Run("absent", func(t *testing.T) {
file := writeFile(t, "bridge-fp-", dynamicModuleContent)
defer cleanupFile(t, file)
err := f.searchFile("nonexistent", file, f.regexp(dynamicModuleRe, "nonexistent"))
require.EqualError(t, err, fmt.Sprintf("module nonexistent not in %s", file))
})
})
t.Run("builtin module", func(t *testing.T) {
t.Run("present", func(t *testing.T) {
file := writeFile(t, "bridge-fp-", builtinModuleContent)
defer cleanupFile(t, file)
err := f.searchFile("bridge", file, f.regexp(builtinModuleRe, "bridge"))
require.NoError(t, err)
})
t.Run("absent", func(t *testing.T) {
file := writeFile(t, "bridge-fp-", builtinModuleContent)
defer cleanupFile(t, file)
err := f.searchFile("nonexistent", file, f.regexp(builtinModuleRe, "nonexistent"))
require.EqualError(t, err, fmt.Sprintf("module nonexistent not in %s", file))
})
})
t.Run("dynamic unloaded module", func(t *testing.T) {
t.Run("present", func(t *testing.T) {
file := writeFile(t, "bridge-fp-", dependsModuleContent)
defer cleanupFile(t, file)
err := f.searchFile("bridge", file, f.regexp(dependsModuleRe, "bridge"))
require.NoError(t, err)
})
t.Run("absent", func(t *testing.T) {
file := writeFile(t, "bridge-fp-", dependsModuleContent)
defer cleanupFile(t, file)
err := f.searchFile("nonexistent", file, f.regexp(dependsModuleRe, "nonexistent"))
require.EqualError(t, err, fmt.Sprintf("module nonexistent not in %s", file))
})
})
}