cubeops: key the login rate limiter on the real peer IP, and bound the failure map #1378
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,200 @@ | ||
| // Copyright (c) 2026 Tencent Inc. | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
|
||
| package auth | ||
|
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||
| import ( | ||
| "fmt" | ||
| "net/http" | ||
| "net/http/httptest" | ||
| "testing" | ||
| "time" | ||
|
|
||
| "github.com/gin-gonic/gin" | ||
| ) | ||
|
|
||
| func newLimiterRouter(t *testing.T, trustedProxies []string) *gin.Engine { | ||
| t.Helper() | ||
| gin.SetMode(gin.TestMode) | ||
| r := gin.New() | ||
| if err := r.SetTrustedProxies(trustedProxies); err != nil { | ||
| t.Fatalf("SetTrustedProxies: %v", err) | ||
| } | ||
| r.POST("/login", LoginRateLimit(), func(c *gin.Context) { | ||
| markLoginFailure(c) | ||
| c.Status(http.StatusUnauthorized) | ||
| }) | ||
| return r | ||
| } | ||
|
|
||
| func attempt(r *gin.Engine, peer string, xff string) int { | ||
| req := httptest.NewRequest(http.MethodPost, "/login", nil) | ||
| req.RemoteAddr = peer | ||
| if xff != "" { | ||
| req.Header.Set("X-Forwarded-For", xff) | ||
| } | ||
| w := httptest.NewRecorder() | ||
| r.ServeHTTP(w, req) | ||
| return w.Code | ||
| } | ||
|
|
||
| func countBlocked(r *gin.Engine, peer string, xffs []string) int { | ||
| blocked := 0 | ||
| for _, xff := range xffs { | ||
| if attempt(r, peer, xff) == http.StatusTooManyRequests { | ||
| blocked++ | ||
| } | ||
| } | ||
| return blocked | ||
| } | ||
|
|
||
| func resetLimiter(t *testing.T) { | ||
| t.Helper() | ||
| defaultLoginLimiter.mu.Lock() | ||
| defaultLoginLimiter.failures = map[string][]time.Time{} | ||
| defaultLoginLimiter.mu.Unlock() | ||
| } | ||
|
|
||
| func TestRotatingForwardedForCannotBypassTheLimiter(t *testing.T) { | ||
| resetLimiter(t) | ||
| r := newLimiterRouter(t, nil) | ||
|
|
||
| xffs := make([]string, 0, 40) | ||
| for i := 0; i < 40; i++ { | ||
| xffs = append(xffs, "10.1.1."+string(rune('0'+i%10))+"9") | ||
| } | ||
|
|
||
| blocked := countBlocked(r, "203.0.113.9:1234", xffs) | ||
| if blocked == 0 { | ||
| t.Fatal("rotating X-Forwarded-For bypassed the limiter entirely") | ||
| } | ||
| if blocked < 30 { | ||
| t.Fatalf("only %d/40 attempts were blocked; the peer IP is not being used as the key", blocked) | ||
| } | ||
| } | ||
|
|
||
| func TestWhitespacePaddedForwardedForCannotBypassTheLimiter(t *testing.T) { | ||
| resetLimiter(t) | ||
| r := newLimiterRouter(t, nil) | ||
|
|
||
| xffs := make([]string, 0, 20) | ||
| for i := 0; i < 20; i++ { | ||
| pad := "" | ||
| for j := 0; j < i; j++ { | ||
| pad += " " | ||
| } | ||
| xffs = append(xffs, pad+"198.51.100.7") | ||
| } | ||
|
|
||
| if blocked := countBlocked(r, "203.0.113.9:1234", xffs); blocked == 0 { | ||
| t.Fatal("whitespace-padded X-Forwarded-For bypassed the limiter") | ||
| } | ||
| } | ||
|
|
||
| func TestLimiterStillFiresWithoutForwardedFor(t *testing.T) { | ||
| resetLimiter(t) | ||
| r := newLimiterRouter(t, nil) | ||
|
|
||
| blocked := 0 | ||
| for i := 0; i < 10; i++ { | ||
| if attempt(r, "203.0.113.9:1234", "") == http.StatusTooManyRequests { | ||
| blocked++ | ||
| } | ||
| } | ||
| if blocked == 0 { | ||
| t.Fatal("baseline broken: the limiter never fired") | ||
| } | ||
| } | ||
|
|
||
| func TestDistinctPeerIPsGetIndependentBuckets(t *testing.T) { | ||
| resetLimiter(t) | ||
| r := newLimiterRouter(t, nil) | ||
|
|
||
| for i := 0; i < 6; i++ { | ||
| attempt(r, "203.0.113.9:1234", "") | ||
| } | ||
| if code := attempt(r, "203.0.113.9:1234", ""); code != http.StatusTooManyRequests { | ||
| t.Fatalf("first peer should be blocked, got %d", code) | ||
| } | ||
| if code := attempt(r, "203.0.113.10:1234", ""); code == http.StatusTooManyRequests { | ||
| t.Fatal("a different peer IP was blocked by another peer's failures") | ||
| } | ||
| } | ||
|
|
||
| func TestTrustedProxyForwardedForIsHonoured(t *testing.T) { | ||
| resetLimiter(t) | ||
| r := newLimiterRouter(t, []string{"203.0.113.9"}) | ||
|
|
||
| for i := 0; i < 6; i++ { | ||
| attempt(r, "203.0.113.9:1234", "198.51.100.7") | ||
| } | ||
| if code := attempt(r, "203.0.113.9:1234", "198.51.100.7"); code != http.StatusTooManyRequests { | ||
| t.Fatalf("a client behind a trusted proxy should be blocked, got %d", code) | ||
| } | ||
| if code := attempt(r, "203.0.113.9:1234", "198.51.100.8"); code == http.StatusTooManyRequests { | ||
| t.Fatal("a different client behind the same trusted proxy was blocked") | ||
| } | ||
| } | ||
|
|
||
| func distinctIP(i int) string { | ||
| return fmt.Sprintf("10.%d.%d.%d", (i>>16)&0xff, (i>>8)&0xff, i&0xff) | ||
| } | ||
|
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| func mapSize(l *loginLimiter) int { | ||
| l.mu.Lock() | ||
| defer l.mu.Unlock() | ||
| return len(l.failures) | ||
| } | ||
|
|
||
| func TestExpiredEntriesAreSweptOnceTheThresholdIsReached(t *testing.T) { | ||
| l := &loginLimiter{failures: map[string][]time.Time{}, limit: 5, window: 20 * time.Millisecond} | ||
| for i := 0; i < sweepThreshold; i++ { | ||
| l.recordFailure(distinctIP(i)) | ||
| } | ||
| if got := mapSize(l); got != sweepThreshold { | ||
| t.Fatalf("map holds %d entries before the sweep, want %d", got, sweepThreshold) | ||
| } | ||
|
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| time.Sleep(40 * time.Millisecond) | ||
| l.recordFailure(distinctIP(sweepThreshold)) | ||
|
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| if got := mapSize(l); got != 1 { | ||
| t.Fatalf("map holds %d entries after the sweep, want only the fresh one", got) | ||
| } | ||
| } | ||
|
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| func TestLiveEntriesAreEvictedSoTheMapStaysBounded(t *testing.T) { | ||
| l := &loginLimiter{failures: map[string][]time.Time{}, limit: 5, window: time.Hour} | ||
| const total = sweepThreshold * 3 | ||
| low := total | ||
| for i := 0; i < total; i++ { | ||
| l.recordFailure(distinctIP(i)) | ||
| got := mapSize(l) | ||
| if got > sweepThreshold { | ||
| t.Fatalf("map grew to %d entries at i=%d, above the threshold %d", got, i, sweepThreshold) | ||
| } | ||
| if i >= total-sweepThreshold && got < low { | ||
| low = got | ||
| } | ||
| } | ||
| if low > evictTarget+1 { | ||
| t.Fatalf("map never fell below %d entries, so live entries are never evicted", low) | ||
| } | ||
| } | ||
|
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| func TestEvictionKeepsTheMostRecentAttackers(t *testing.T) { | ||
| l := &loginLimiter{failures: map[string][]time.Time{}, limit: 5, window: time.Hour} | ||
| for i := 0; i < sweepThreshold-6; i++ { | ||
|
There was a problem hiding this comment. The eviction path is never exercised here. As written, this test would pass even if To actually hit the branch, the map needs to be at |
||
| l.recordFailure(distinctIP(i)) | ||
| } | ||
|
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| recent := "203.0.113.7" | ||
| for i := 0; i < 5; i++ { | ||
| l.recordFailure(recent) | ||
| } | ||
| l.recordFailure(distinctIP(sweepThreshold)) | ||
|
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||
| if !l.isBlocked(recent) { | ||
| t.Fatal("the most recently active IP was evicted, so its failures were forgotten") | ||
| } | ||
| } | ||
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sweepThresholdis a sweep trigger, not a cap. The sweep only removes expired entries, so during an ongoing distributed attack (all entries live, within the window) the map keeps growing past 4096 and every subsequentrecordFailurepays a full O(map) sweep while holdingl.mu— CPU + lock-contention amplification under exactly the attack this limiter exists to blunt. The PR description's claim that "the map stays at or below sweepThreshold" holds only once entries expire. Consider evicting when the map exceeds the threshold (not just sweeping), or document that this bounds steady-state memory rather than peak.