acme: automatically retry on badNonce errors
After receiving a badNonce error, the call can be safely retried. Nonce
errors can happen unexpectedly based on an unknown expiration date or
server-side changes. Rather than force the caller handle these errors,
retryPostJWS will keep retrying until success or a different error.
According to the spec, the error returned should be
"urn:ietf:params:acme:error:badNonce", but the error that Let's Encrypt
returns is "urn:acme:error:badNonce" so we just check the suffix.
Fixes golang/go#19703
Change-Id: Id15012dff91e51d28ed8bc54f13a6212186cb7df
Reviewed-on: https://go-review.googlesource.com/40130
Run-TryBot: Alex Vaghin <ddos@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Vaghin <ddos@google.com>
diff --git a/acme/acme.go b/acme/acme.go
index 140d422..d650604 100644
--- a/acme/acme.go
+++ b/acme/acme.go
@@ -198,7 +198,7 @@
req.NotAfter = now.Add(exp).Format(time.RFC3339)
}
- res, err := c.postJWS(ctx, c.Key, c.dir.CertURL, req)
+ res, err := c.retryPostJWS(ctx, c.Key, c.dir.CertURL, req)
if err != nil {
return nil, "", err
}
@@ -273,7 +273,7 @@
if key == nil {
key = c.Key
}
- res, err := c.postJWS(ctx, key, c.dir.RevokeURL, body)
+ res, err := c.retryPostJWS(ctx, key, c.dir.RevokeURL, body)
if err != nil {
return err
}
@@ -361,7 +361,7 @@
Resource: "new-authz",
Identifier: authzID{Type: "dns", Value: domain},
}
- res, err := c.postJWS(ctx, c.Key, c.dir.AuthzURL, req)
+ res, err := c.retryPostJWS(ctx, c.Key, c.dir.AuthzURL, req)
if err != nil {
return nil, err
}
@@ -419,7 +419,7 @@
Status: "deactivated",
Delete: true,
}
- res, err := c.postJWS(ctx, c.Key, url, req)
+ res, err := c.retryPostJWS(ctx, c.Key, url, req)
if err != nil {
return err
}
@@ -438,21 +438,7 @@
// In all other cases WaitAuthorization returns an error.
// If the Status is StatusInvalid, the returned error is ErrAuthorizationFailed.
func (c *Client) WaitAuthorization(ctx context.Context, url string) (*Authorization, error) {
- var count int
- sleep := func(v string, inc int) error {
- count += inc
- d := backoff(count, 10*time.Second)
- d = retryAfter(v, d)
- wakeup := time.NewTimer(d)
- defer wakeup.Stop()
- select {
- case <-ctx.Done():
- return ctx.Err()
- case <-wakeup.C:
- return nil
- }
- }
-
+ sleep := sleeper(ctx)
for {
res, err := c.get(ctx, url)
if err != nil {
@@ -525,7 +511,7 @@
Type: chal.Type,
Auth: auth,
}
- res, err := c.postJWS(ctx, c.Key, chal.URI, req)
+ res, err := c.retryPostJWS(ctx, c.Key, chal.URI, req)
if err != nil {
return nil, err
}
@@ -658,7 +644,7 @@
req.Contact = acct.Contact
req.Agreement = acct.AgreedTerms
}
- res, err := c.postJWS(ctx, c.Key, url, req)
+ res, err := c.retryPostJWS(ctx, c.Key, url, req)
if err != nil {
return nil, err
}
@@ -695,6 +681,40 @@
}, nil
}
+// retryPostJWS will retry calls to postJWS if there is a badNonce error,
+// clearing the stored nonces after each error.
+// If the response was 4XX-5XX, then responseError is called on the body,
+// the body is closed, and the error returned.
+func (c *Client) retryPostJWS(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, error) {
+ sleep := sleeper(ctx)
+ for {
+ res, err := c.postJWS(ctx, key, url, body)
+ if err != nil {
+ return nil, err
+ }
+ // handle errors 4XX-5XX with responseError
+ if res.StatusCode >= 400 && res.StatusCode <= 599 {
+ err := responseError(res)
+ res.Body.Close()
+ // according to spec badNonce is urn:ietf:params:acme:error:badNonce
+ // however, acme servers in the wild return their version of the error
+ // https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-5.4
+ if ae, ok := err.(*Error); ok && strings.HasSuffix(strings.ToLower(ae.ProblemType), ":badnonce") {
+ // clear any nonces that we might've stored that might now be
+ // considered bad
+ c.clearNonces()
+ retry := res.Header.Get("retry-after")
+ if err := sleep(retry, 1); err != nil {
+ return nil, err
+ }
+ continue
+ }
+ return nil, err
+ }
+ return res, nil
+ }
+}
+
// postJWS signs the body with the given key and POSTs it to the provided url.
// The body argument must be JSON-serializable.
func (c *Client) postJWS(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, error) {
@@ -730,6 +750,13 @@
return nonce, nil
}
+// clearNonces clears any stored nonces
+func (c *Client) clearNonces() {
+ c.noncesMu.Lock()
+ defer c.noncesMu.Unlock()
+ c.nonces = make(map[string]struct{})
+}
+
// addNonce stores a nonce value found in h (if any) for future use.
func (c *Client) addNonce(h http.Header) {
v := nonceFromHeader(h)
@@ -941,6 +968,28 @@
return links
}
+// sleeper returns a function that accepts the Retry-After HTTP header value
+// and an increment that's used with backoff to increasingly sleep on
+// consecutive calls until the context is done. If the Retry-After header
+// cannot be parsed, then backoff is used with a maximum sleep time of 10
+// seconds.
+func sleeper(ctx context.Context) func(ra string, inc int) error {
+ var count int
+ return func(ra string, inc int) error {
+ count += inc
+ d := backoff(count, 10*time.Second)
+ d = retryAfter(ra, d)
+ wakeup := time.NewTimer(d)
+ defer wakeup.Stop()
+ select {
+ case <-ctx.Done():
+ return ctx.Err()
+ case <-wakeup.C:
+ return nil
+ }
+ }
+}
+
// retryAfter parses a Retry-After HTTP header value,
// trying to convert v into an int (seconds) or use http.ParseTime otherwise.
// It returns d if v cannot be parsed.
diff --git a/acme/acme_test.go b/acme/acme_test.go
index b91533d..0210ce3 100644
--- a/acme/acme_test.go
+++ b/acme/acme_test.go
@@ -1065,6 +1065,44 @@
}
}
+func TestRetryPostJWS(t *testing.T) {
+ var count int
+ ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ count++
+ w.Header().Set("replay-nonce", fmt.Sprintf("nonce%d", count))
+ if r.Method == "HEAD" {
+ // We expect the client to do 2 head requests to fetch
+ // nonces, one to start and another after getting badNonce
+ return
+ }
+
+ head, err := decodeJWSHead(r)
+ if err != nil {
+ t.Errorf("decodeJWSHead: %v", err)
+ } else if head.Nonce == "" {
+ t.Error("head.Nonce is empty")
+ } else if head.Nonce == "nonce1" {
+ // return a badNonce error to force the call to retry
+ w.WriteHeader(http.StatusBadRequest)
+ w.Write([]byte(`{"type":"urn:ietf:params:acme:error:badNonce"}`))
+ return
+ }
+ // Make client.Authorize happy; we're not testing its result.
+ w.WriteHeader(http.StatusCreated)
+ w.Write([]byte(`{"status":"valid"}`))
+ }))
+ defer ts.Close()
+
+ client := Client{Key: testKey, dir: &Directory{AuthzURL: ts.URL}}
+ // This call will fail with badNonce, causing a retry
+ if _, err := client.Authorize(context.Background(), "example.com"); err != nil {
+ t.Errorf("client.Authorize 1: %v", err)
+ }
+ if count != 4 {
+ t.Errorf("total requests count: %d; want 4", count)
+ }
+}
+
func TestLinkHeader(t *testing.T) {
h := http.Header{"Link": {
`<https://example.com/acme/new-authz>;rel="next"`,
