Pulse/cmd/pulse-sensor-proxy/ssh_test.go
rcourtman b2e65f7b3e feat(security): Add SSH output limits and improve host key management
Addresses two security vulnerabilities:

1. SSH Output Size Limits:
   - Prevents memory exhaustion from malicious remote nodes
   - Configurable max_ssh_output_bytes (default 1MB)
   - Stream with io.LimitReader to cap output size
   - New metric: pulse_proxy_ssh_output_oversized_total{node}
   - WARN logging for oversized outputs

2. Improved Host Key Management:
   - Seed host keys from Proxmox cluster store (/etc/pve/priv/known_hosts)
   - Falls back to ssh-keyscan only if Proxmox unavailable (with WARN)
   - Fingerprint change detection with ERROR logging
   - require_proxmox_hostkeys option for strict mode
   - New metric: pulse_proxy_hostkey_changes_total{node}
   - Reduces MITM attack surface significantly

Known hosts manager now normalizes entries, reuses existing fingerprints,
and raises typed HostKeyChangeError when fingerprints differ.

Related to security audit 2025-11-07.

Co-authored-by: Codex <codex@openai.com>
2025-11-07 17:09:02 +00:00

174 lines
5.3 KiB
Go

package main
import (
"bytes"
"encoding/json"
"fmt"
"os"
"os/exec"
"path/filepath"
"strings"
"testing"
)
func setupTempWrapper(t *testing.T) (scriptPath, thermalFile, binDir, baseDir string) {
t.Helper()
baseDir = t.TempDir()
thermalDir := filepath.Join(baseDir, "sys", "class", "thermal", "thermal_zone0")
if err := os.MkdirAll(thermalDir, 0o755); err != nil {
t.Fatalf("failed to create thermal zone directory: %v", err)
}
thermalFile = filepath.Join(thermalDir, "temp")
scriptContent := strings.ReplaceAll(tempWrapperScript, "/sys/class/thermal/thermal_zone0/temp", thermalFile)
scriptPath = filepath.Join(baseDir, "temp-wrapper.sh")
if err := os.WriteFile(scriptPath, []byte(scriptContent), 0o755); err != nil {
t.Fatalf("failed to write wrapper script: %v", err)
}
binDir = filepath.Join(baseDir, "bin")
if err := os.MkdirAll(binDir, 0o755); err != nil {
t.Fatalf("failed to create bin directory: %v", err)
}
linkCommand := func(name string) {
target, err := exec.LookPath(name)
if err != nil {
t.Fatalf("required command %q not found on host: %v", name, err)
}
content := fmt.Sprintf("#!/bin/sh\nexec %s \"$@\"\n", target)
if err := os.WriteFile(filepath.Join(binDir, name), []byte(content), 0o755); err != nil {
t.Fatalf("failed to create shim for %s: %v", name, err)
}
}
linkCommand("awk")
linkCommand("cat")
return scriptPath, thermalFile, binDir, baseDir
}
func runTempWrapper(t *testing.T, scriptPath, binDir string, extraEnv ...string) []byte {
t.Helper()
cmd := exec.Command("sh", scriptPath)
env := []string{"PATH=" + binDir}
env = append(env, extraEnv...)
cmd.Env = env
output, err := cmd.CombinedOutput()
if err != nil {
t.Fatalf("temp wrapper failed: %v (output: %s)", err, strings.TrimSpace(string(output)))
}
return output
}
func TestTempWrapperFallbackWhenSensorsMissing(t *testing.T) {
scriptPath, thermalFile, binDir, _ := setupTempWrapper(t)
if err := os.WriteFile(thermalFile, []byte("51234\n"), 0o644); err != nil {
t.Fatalf("failed to write thermal zone temperature: %v", err)
}
output := runTempWrapper(t, scriptPath, binDir)
var data map[string]map[string]map[string]float64
if err := json.Unmarshal(output, &data); err != nil {
t.Fatalf("failed to parse wrapper output as JSON: %v (output: %s)", err, strings.TrimSpace(string(output)))
}
temp1, ok := data["rpitemp-virtual"]["temp1"]["temp1_input"]
if !ok {
t.Fatalf("expected rpitemp-virtual temp1 reading in output: %v", data)
}
if temp1 != 51.23 {
t.Fatalf("expected converted temperature 51.23, got %.2f", temp1)
}
}
func TestTempWrapperFallbackWhenSensorsEmpty(t *testing.T) {
scriptPath, thermalFile, binDir, _ := setupTempWrapper(t)
sensorsStub := filepath.Join(binDir, "sensors")
content := "#!/bin/sh\nexit 0\n"
if err := os.WriteFile(sensorsStub, []byte(content), 0o755); err != nil {
t.Fatalf("failed to create sensors stub: %v", err)
}
if err := os.WriteFile(thermalFile, []byte("47890\n"), 0o644); err != nil {
t.Fatalf("failed to write thermal zone temperature: %v", err)
}
output := runTempWrapper(t, scriptPath, binDir)
var data map[string]map[string]map[string]float64
if err := json.Unmarshal(output, &data); err != nil {
t.Fatalf("failed to parse wrapper output as JSON: %v (output: %s)", err, strings.TrimSpace(string(output)))
}
temp1, ok := data["rpitemp-virtual"]["temp1"]["temp1_input"]
if !ok {
t.Fatalf("expected rpitemp-virtual temp1 reading in output: %v", data)
}
if temp1 != 47.89 {
t.Fatalf("expected converted temperature 47.89, got %.2f", temp1)
}
}
func TestTempWrapperPrefersSensorsOutput(t *testing.T) {
scriptPath, thermalFile, binDir, _ := setupTempWrapper(t)
jsonOutput := `{"cpu_thermal-virtual-0":{"temp1":{"temp1_input":42.5}}}`
sensorsStub := filepath.Join(binDir, "sensors")
content := fmt.Sprintf("#!/bin/sh\nprintf '%s'\n", jsonOutput)
if err := os.WriteFile(sensorsStub, []byte(content), 0o755); err != nil {
t.Fatalf("failed to create sensors stub: %v", err)
}
// Ensure thermal zone file exists but should be ignored
if err := os.WriteFile(thermalFile, []byte("40000\n"), 0o644); err != nil {
t.Fatalf("failed to write thermal zone temperature: %v", err)
}
output := runTempWrapper(t, scriptPath, binDir)
trimmed := strings.TrimSpace(string(output))
if trimmed != jsonOutput {
t.Fatalf("expected wrapper to return sensors output %s, got %s", jsonOutput, trimmed)
}
}
func TestReadAllWithLimit(t *testing.T) {
reader := bytes.NewBufferString("abcdefg")
data, exceeded, err := readAllWithLimit(reader, 4)
if err != nil {
t.Fatalf("readAllWithLimit returned error: %v", err)
}
if string(data) != "abcd" {
t.Fatalf("expected truncated output 'abcd', got %q", string(data))
}
if !exceeded {
t.Fatalf("expected exceeded flag when data exceeds limit")
}
reader2 := bytes.NewBufferString("xyz")
data, exceeded, err = readAllWithLimit(reader2, 10)
if err != nil {
t.Fatalf("readAllWithLimit returned error: %v", err)
}
if string(data) != "xyz" {
t.Fatalf("expected full output 'xyz', got %q", string(data))
}
if exceeded {
t.Fatalf("did not expect exceeded flag for small output")
}
reader3 := bytes.NewBufferString("12345")
data, exceeded, err = readAllWithLimit(reader3, 0)
if err != nil {
t.Fatalf("readAllWithLimit returned error: %v", err)
}
if string(data) != "12345" || exceeded {
t.Fatalf("expected unlimited read to return full data without exceeding")
}
}