mixandCursor
81190a7aad
test / test (push) Has been cancelled
Implement phase 1 and 2 review actions (DMARC UI CSS fixes, bounded DMARC ingest stdin, rate-limit eviction hardening, settings/user handler cleanup, shared atomic/supervisor helpers) and phase 3 documentation/changelog updates including roadmap and accepted-risk notes. Co-authored-by: Cursor <cursoragent@cursor.com>
109 lines
2.1 KiB
Go
109 lines
2.1 KiB
Go
package auth
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import (
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"sync"
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"time"
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)
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const defaultMaxBuckets = 4096
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// rateLimiter is a simple fixed-window per-key counter used to throttle the
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// setup and login routes (security.md). Keys are client IPs.
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type rateLimiter struct {
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max int
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window time.Duration
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maxBuckets int
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mu sync.Mutex
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buckets map[string]*rlBucket
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}
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type rlBucket struct {
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count int
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windowEnds time.Time
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}
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func newRateLimiter(max int, window time.Duration) *rateLimiter {
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return &rateLimiter{
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max: max,
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window: window,
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maxBuckets: defaultMaxBuckets,
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buckets: make(map[string]*rlBucket),
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}
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}
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func (r *rateLimiter) startSweeper() {
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go func() {
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ticker := time.NewTicker(r.window)
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defer ticker.Stop()
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for range ticker.C {
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r.mu.Lock()
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r.sweep(time.Now())
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r.mu.Unlock()
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}
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}()
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}
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func (r *rateLimiter) Allow(key string) bool {
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now := time.Now()
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r.mu.Lock()
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defer r.mu.Unlock()
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b := r.buckets[key]
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if b == nil || now.After(b.windowEnds) {
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r.makeRoom(now)
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r.buckets[key] = &rlBucket{count: 1, windowEnds: now.Add(r.window)}
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r.sweep(now)
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return true
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}
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if b.count >= r.max {
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return false
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}
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b.count++
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return true
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}
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func (r *rateLimiter) makeRoom(now time.Time) {
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if r.maxBuckets <= 0 || len(r.buckets) < r.maxBuckets {
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return
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}
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r.sweep(now)
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for len(r.buckets) >= r.maxBuckets {
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if !r.evictNearest() {
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break
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}
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}
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}
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// evictNearest removes the bucket whose window ends soonest, skipping buckets
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// that are currently blocked (count >= max) so an attacker cannot flush active
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// rate-limit state by filling the map with new keys.
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func (r *rateLimiter) evictNearest() bool {
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var bestKey string
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var bestEnds time.Time
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first := true
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for k, b := range r.buckets {
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if b.count >= r.max {
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continue
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}
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if first || b.windowEnds.Before(bestEnds) {
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bestKey = k
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bestEnds = b.windowEnds
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first = false
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}
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}
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if bestKey == "" {
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return false
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}
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delete(r.buckets, bestKey)
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return true
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}
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func (r *rateLimiter) sweep(now time.Time) {
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for k, b := range r.buckets {
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if now.After(b.windowEnds) {
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delete(r.buckets, k)
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}
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}
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}
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