smallwebwaf/internal/waf/trappaths_test.go

package waf_test

import (
	"net/http"
	"net/netip"
	"reflect"
	"testing"
	"time"

	"sneak.berlin/go/smallwebwaf/internal/bans"
	"sneak.berlin/go/smallwebwaf/internal/requestlog"
)

// trapPaths is the setting's name, and trapPathList what the tests set it
// to.
const (
	trapPaths    = "SWW_TRAP_PATHS"
	trapPathList = "/wp-login.php,/xmlrpc.php"
)

func TestTrapPathBansAsABanRuleDoes(t *testing.T) {
	t.Parallel()

	const allowed = "192.0.2.60" // in SWW_ALLOW_NETS

	// A block rule for the same path: the trap path comes first.
	s, clk, server := startWithClock(t, "", map[string]string{
		trapPaths:   trapPathList,
		rulesDir:    writeRules(t, `wp  path  block  ^/wp-login\.php$`),
		allowNets:   allowed,
		banResponse: "429",
	})
	start := clk.Now()

	// Only the path itself, the whole of it in the same case, is a trap
	// path.
	for _, path := range []string{"/wp-login.php/", "/WP-LOGIN.PHP", "/blog/xmlrpc.php"} {
		s.request(otherClient, path, http.StatusOK, requestlog.ActionForward)
	}

	// A client in SWW_ALLOW_NETS is not checked.
	s.request(
		allowed,
		"/xmlrpc.php",
		http.StatusOK,
		requestlog.ActionForward,
	)

	// The query is not part of the path.
	line := s.request(
		client,
		"/wp-login.php?redirect_to=x",
		http.StatusTooManyRequests,
		requestlog.ActionTemporarilyBanned,
	)
	wantRuleIDs(t, line)

	if line.BanExpires != requestlog.FormatTime(start.Add(7*24*time.Hour)) {
		t.Errorf(
			"log line has ban_expires %q, want seven days on",
			line.BanExpires,
		)
	}

	netblock := netip.MustParsePrefix(client + "/32")
	want := bans.Ban{
		Netblock: netblock,
		Start:    start,
		Expires:  start.Add(7 * 24 * time.Hour),
		Cause:    bans.CauseAttack,
		Reason:   "asked for the trap path /wp-login.php",
		Notes: bans.Notes{
			TrapPath: "/wp-login.php",
			Request: bans.Request{
				Time:      start,
				Method:    http.MethodGet,
				Host:      appHost,
				Path:      "/wp-login.php?redirect_to=x",
				Status:    http.StatusTooManyRequests,
				UserAgent: userAgent,
			},
			Requests: 1,
		},
	}

	got := server.Ledger.Bans(netblock)
	if len(got) != 1 || !reflect.DeepEqual(got[0], want) {
		t.Fatalf("bans\n%+v\nwant\n%+v", got, want)
	}

	// The next request is refused under the ban, and makes it permanent.
	line = s.get(
		client,
		http.StatusTooManyRequests,
		requestlog.ActionPermanentlyBanned,
	)
	if line.BanExpires != permanent {
		t.Errorf(
			"log line has ban_expires %q, want permanent",
			line.BanExpires,
		)
	}
}

func TestTrapPathRefusalNamesItsHeuristicAndPath(t *testing.T) {
	t.Parallel()

	s, _, _ := startWithClock(
		t,
		"",
		map[string]string{trapPaths: trapPathList},
	)

	line := s.request(
		client,
		"/wp-login.php?redirect_to=x",
		http.StatusForbidden,
		requestlog.ActionTemporarilyBanned,
	)
	wantHeuristic(t, line, "trap_paths", `{"path": "/wp-login.php"}`)
}

func TestTrapPathMatchesThePathDecodedOnce(t *testing.T) {
	t.Parallel()

	s, _, server := startWithClock(
		t,
		"",
		map[string]string{trapPaths: trapPathList},
	)

	// %2577 decodes once to %77, not to w.
	s.request(
		otherClient,
		"/%2577p-login.php",
		http.StatusOK,
		requestlog.ActionForward,
	)
	s.request(client, "/%77p-login.php", http.StatusForbidden,
		requestlog.ActionTemporarilyBanned)

	// The ban's notes give the path as the client sent it.
	got := server.Ledger.Bans(netip.MustParsePrefix(client + "/32"))
	if len(got) != 1 || got[0].Notes.TrapPath != "/%77p-login.php" {
		t.Fatalf(
			"bans %+v, want one whose notes give the trap path /%%77p-login.php",
			got,
		)
	}
}

func TestTrapPathsNeedNoRuleFiles(t *testing.T) {
	t.Parallel()

	s, _, _ := startWithClock(t, "", map[string]string{
		trapPaths:           trapPathList,
		"SWW_RULES_ENABLED": "false",
	})

	s.request(client, "/xmlrpc.php", http.StatusForbidden,
		requestlog.ActionTemporarilyBanned)
}

func TestObserveModeLogsWhatATrapPathWouldDo(t *testing.T) {
	t.Parallel()

	s, _, server := startWithClock(t, "", map[string]string{
		trapPaths: trapPathList,
		mode:      observe,
	})

	line := s.request(
		client,
		"/xmlrpc.php",
		http.StatusOK,
		requestlog.ActionForward,
	)
	wantWouldAction(t, line, requestlog.ActionTemporarilyBanned)

	// No ban was made.
	s.get(client, http.StatusOK, requestlog.ActionForward)

	if got := server.Ledger.Snapshot(); len(got) != 0 {
		t.Errorf("bans %+v, want none", got)
	}
}