initial commit

vendor/github.com/ericchiang/oidc/oidcproxy/nonce.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"io"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+var (
+	gcInterval = time.Minute
+	expiresIn  = time.Minute * 10
+)
+
+type memNonceSource struct {
+	mu     sync.Mutex
+	nonces map[string]time.Time
+}
+
+func newNonceSource(ctx context.Context) *memNonceSource {
+	s := &memNonceSource{nonces: make(map[string]time.Time)}
+	go s.garbageCollect(ctx)
+	return s
+}
+
+func (s *memNonceSource) Nonce() (string, error) {
+	buff := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, buff); err != nil {
+		return "", err
+	}
+	nonce := base64.RawURLEncoding.EncodeToString(buff)
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.nonces[nonce] = time.Now().Add(expiresIn)
+
+	return nonce, nil
+}
+
+func (s *memNonceSource) ClaimNonce(nonce string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, ok := s.nonces[nonce]; ok {
+		delete(s.nonces, nonce)
+		return nil
+	}
+	return errors.New("invalid nonce")
+}
+
+func (s *memNonceSource) garbageCollect(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+		case <-time.After(gcInterval):
+			s.mu.Lock()
+			now := time.Now()
+
+			for nonce, exp := range s.nonces {
+				if now.After(exp) {
+					delete(s.nonces, nonce)
+				}
+			}
+
+			s.mu.Unlock()
+		}
+	}
+}