Files
gotenberg/pkg/modules/chromium/scopebudget_test.go

123 lines
3.2 KiB
Go

package chromium
import (
"strings"
"sync"
"testing"
"time"
"github.com/dlclark/regexp2"
)
func TestScopeMatchBudget(t *testing.T) {
t.Run("allows matching while credit remains", func(t *testing.T) {
b := newScopeMatchBudget(time.Second)
if !b.tryAcquire() {
t.Fatal("tryAcquire() = false on a fresh budget, want true")
}
})
t.Run("denies matching once exhausted", func(t *testing.T) {
b := newScopeMatchBudget(time.Second)
b.consume(time.Second)
if b.tryAcquire() {
t.Error("tryAcquire() = true after the budget was spent, want false")
}
})
t.Run("saturates at zero instead of wrapping into credit", func(t *testing.T) {
b := newScopeMatchBudget(time.Second)
b.consume(time.Hour)
if got := b.remaining.Load(); got != 0 {
t.Errorf("remaining = %d, want 0", got)
}
if b.tryAcquire() {
t.Error("tryAcquire() = true after an overlong match, want false")
}
})
t.Run("a spent budget stays spent", func(t *testing.T) {
b := newScopeMatchBudget(time.Second)
b.consume(time.Second)
b.consume(time.Millisecond)
if got := b.remaining.Load(); got != 0 {
t.Errorf("remaining = %d, want 0", got)
}
})
t.Run("is safe for concurrent use", func(t *testing.T) {
const goroutines = 64
// Each goroutine spends 1ms against a budget of half that many
// milliseconds, so the total spend overshoots it.
b := newScopeMatchBudget(time.Duration(goroutines/2) * time.Millisecond)
var wg sync.WaitGroup
for range goroutines {
wg.Go(func() {
b.tryAcquire()
b.consume(time.Millisecond)
})
}
wg.Wait()
if got := b.remaining.Load(); got != 0 {
t.Errorf("remaining = %d, want 0", got)
}
})
}
// TestScopeMatchBudget_BoundsCatastrophicBacktracking is the regression test for
// the amplification: many scoped headers matched against a hostile URL must cost
// the budget, not a multiple of it.
// See https://github.com/gotenberg/gotenberg/issues/1588.
func TestScopeMatchBudget_BoundsCatastrophicBacktracking(t *testing.T) {
const (
headers = 16
budget = 200 * time.Millisecond
)
// Nested quantifier with no possible match: classic catastrophic
// backtracking.
pattern := compileScopePattern(t, `(a+)+b`)
url := "http://example.com/" + strings.Repeat("a", 40)
b := newScopeMatchBudget(budget)
start := time.Now()
var matched int
for range headers {
if !b.tryAcquire() {
break
}
matchStart := time.Now()
_, _ = pattern.MatchString(url)
b.consume(time.Since(matchStart))
matched++
}
elapsed := time.Since(start)
if matched == headers {
t.Errorf("all %d headers were matched, want the budget to stop matching early", headers)
}
// Each match is separately capped at extraHttpHeaderScopeMatchTimeout, so
// the worst case is the budget plus one final match that started with the
// last of the credit. Generous slack keeps this stable on a loaded CI box.
ceiling := budget + extraHttpHeaderScopeMatchTimeout + time.Second
if elapsed > ceiling {
t.Errorf("matching took %s, want at most %s", elapsed, ceiling)
}
}
func compileScopePattern(t *testing.T, pattern string) *regexp2.Regexp {
t.Helper()
p, err := regexp2.Compile(pattern, regexp2.None)
if err != nil {
t.Fatalf("compile %q: %v", pattern, err)
}
p.MatchTimeout = extraHttpHeaderScopeMatchTimeout
return p
}