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Copy pathgeneric.go
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1017 lines (861 loc) · 31 KB
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package letsdebug
import (
"context"
"crypto/x509"
"database/sql"
"encoding/pem"
"encoding/xml"
"errors"
"net"
"os"
"regexp"
"sort"
"strings"
"sync"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
"golang.org/x/net/idna"
"golang.org/x/text/unicode/norm"
"github.com/eggsampler/acme/v3"
"fmt"
"net/http"
"net/url"
"time"
"encoding/json"
// Driver for crtwatch/ratelimitChecker
_ "github.com/lib/pq"
"github.com/miekg/dns"
"github.com/weppos/publicsuffix-go/net/publicsuffix"
psl "github.com/weppos/publicsuffix-go/publicsuffix"
)
// validMethodChecker ensures that the provided authorization method is valid and supported.
type validMethodChecker struct{}
func (c validMethodChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
if validMethods[method] {
return nil, errNotApplicable
}
return []Problem{notValidMethod(method)}, nil
}
func notValidMethod(method ValidationMethod) Problem {
var supportedMethods []string
for k := range validMethods {
supportedMethods = append(supportedMethods, string(k))
}
return Problem{
Name: "InvalidMethod",
Explanation: fmt.Sprintf(`"%s" is not a supported validation method.`, method),
Detail: fmt.Sprintf("Supported methods: %s", strings.Join(supportedMethods, ", ")),
Severity: SeverityFatal,
}
}
var dnsLabelCharacterRegexp = regexp.MustCompile("^[a-z0-9-]+$")
// validDomainChecker ensures that the FQDN is well-formed and is part of a public suffix.
type validDomainChecker struct{}
func (c validDomainChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
var probs []Problem
domain = strings.TrimPrefix(domain, "*.")
if len(domain) == 0 {
probs = append(probs, invalidDomain(domain, fmt.Sprintf("Domain is empty")))
return probs, nil
}
for _, ch := range []byte(domain) {
if !(('a' <= ch && ch <= 'z') ||
('A' <= ch && ch <= 'A') ||
('0' <= ch && ch <= '9') ||
ch == '.' || ch == '-') {
probs = append(probs, invalidDomain(domain, fmt.Sprintf("Invalid character present: %c", ch)))
return probs, nil
}
}
if len(domain) > 253 {
probs = append(probs, invalidDomain(domain, "Domain too long"))
return probs, nil
}
if ip := net.ParseIP(domain); ip != nil {
probs = append(probs, invalidDomain(domain, "Domain is an IP address"))
return probs, nil
}
if strings.HasSuffix(domain, ".") {
probs = append(probs, invalidDomain(domain, "Domain must not end in a dot"))
return probs, nil
}
labels := strings.Split(domain, ".")
if len(labels) > 10 {
probs = append(probs, invalidDomain(domain, "Domain has too many dot"))
return probs, nil
}
if len(labels) < 2 {
probs = append(probs, invalidDomain(domain, "Domain needs at least one dot"))
return probs, nil
}
for _, label := range labels {
if len(label) < 1 {
probs = append(probs, invalidDomain(domain, "Domain can not have two dots in a row"))
return probs, nil
}
if len(label) > 63 {
probs = append(probs, invalidDomain(domain, "Domain has a label (component between dots) longer than 63 bytes"))
return probs, nil
}
if !dnsLabelCharacterRegexp.MatchString(label) {
probs = append(probs, invalidDomain(domain, "Domain contains an invalid character"))
return probs, nil
}
if label[0] == '-' || label[len(label)-1] == '-' {
probs = append(probs, invalidDomain(domain, "Domain contains an invalid label in a reserved format (R-LDH: '??--')"))
return probs, nil
}
if len(label) >= 4 && label[2:4] == "--" {
if label[0:2] != "xn" {
probs = append(probs, invalidDomain(domain, "Domain contains an invalid label in a reserved format (R-LDH: '??--')"))
return probs, nil
}
ulabel, err := idna.ToUnicode(label)
if err != nil {
probs = append(probs, invalidDomain(domain, "Domain contains malformed punycode"))
return probs, nil
}
if !norm.NFC.IsNormalString(ulabel) {
probs = append(probs, invalidDomain(domain, "Domain contains malformed punycode"))
return probs, nil
}
}
}
rule := psl.DefaultList.Find(domain, &psl.FindOptions{IgnorePrivate: true, DefaultRule: nil})
if rule == nil {
probs = append(probs, invalidDomain(domain, "Domain doesn't end in a public TLD"))
return probs, nil
}
if r := rule.Decompose(domain)[1]; r == "" {
probs = append(probs, invalidDomain(domain, "Domain is a TLD"))
return probs, nil
} else {
probs = append(probs, debugProblem("PublicSuffix", "The IANA public suffix is the TLD of the Registered Domain",
fmt.Sprintf("The TLD for %s is: %s", domain, r)))
}
return probs, nil
}
// domainExistsChecker ensures that the registered domain actually exists
type domainExistsChecker struct{}
func (c domainExistsChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
var probs []Problem
domainName, err := psl.Parse(domain)
if err != nil {
probs = append(probs, invalidDomain(domain, "Cannot find registered domain via publix suffix list"))
return probs, nil
}
sld := domainName.SLD + "." + domainName.TLD
soa, err := lookupRaw(sld, dns.TypeSOA)
if err != nil {
probs = append(probs, dnsLookupFailed(sld, "SOA", errors.Join(
errors.New("domain existence could not be verified due to misbehaving nameserver"), err)))
return probs, nil
}
if soa == nil {
probs = append(probs, dnsLookupFailed(sld, "SOA", errors.New("domain existence problem: No DNS response received")))
return probs, nil
}
if soa.NxDomain {
probs = append(probs, invalidDomain(sld, "Domain does not exist in DNS - have you registered this domain name?"))
}
return probs, nil
}
// caaChecker ensures that any caa record on the domain, or up the domain tree, allow issuance for letsencrypt.org
type caaChecker struct{}
func (c caaChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
var probs []Problem
wildcard := false
if strings.HasPrefix(domain, "*.") {
wildcard = true
domain = domain[2:]
}
rrs, err := ctx.Lookup(domain, dns.TypeCAA)
if err != nil {
probs = append(probs, dnsLookupFailed(domain, "CAA", err))
return probs, nil
}
// check any found caa records
if len(rrs) > 0 {
var issue []*dns.CAA
var issuewild []*dns.CAA
var criticalUnknown []*dns.CAA
for _, rr := range rrs {
caaRr, ok := rr.(*dns.CAA)
if !ok {
continue
}
switch caaRr.Tag {
case "issue":
issue = append(issue, caaRr)
case "issuewild":
issuewild = append(issuewild, caaRr)
case "iodef":
break
default:
if caaRr.Flag == 1 {
criticalUnknown = append(criticalUnknown, caaRr)
}
}
}
probs = append(probs, debugProblem("CAA",
"CAA records control authorization for certificate authorities to issue certificates for a domain",
collateRecords(append(issue, issuewild...))))
if len(criticalUnknown) > 0 {
probs = append(probs, caaCriticalUnknown(domain, wildcard, criticalUnknown))
return probs, nil
}
if len(issue) == 0 && !wildcard {
return probs, nil
}
records := issue
if wildcard && len(issuewild) > 0 {
records = issuewild
}
for _, r := range records {
if extractIssuerDomain(r.Value) == "letsencrypt.org" {
return probs, nil
}
}
probs = append(probs, caaIssuanceNotAllowed(domain, wildcard, records))
return probs, nil
}
// recurse up to the public suffix domain until a caa record is found
// a.b.c.com -> b.c.com -> c.com until
if ps, _ := publicsuffix.PublicSuffix(domain); domain != ps && ps != "" {
splitDomain := strings.SplitN(domain, ".", 2)
parentProbs, err := c.Check(ctx, splitDomain[1], method)
if err != nil {
return nil, fmt.Errorf("error checking caa record on domain: %s, %v", splitDomain[1], err)
}
probs = append(probs, parentProbs...)
}
return probs, nil
}
func extractIssuerDomain(value string) string {
// record can be:
// issuedomain.tld; someparams
return strings.Trim(strings.SplitN(value, ";", 2)[0], " \t")
}
func collateRecords(records []*dns.CAA) string {
var s []string
for _, r := range records {
s = append(s, r.String())
}
return strings.Join(s, "\n")
}
func caaCriticalUnknown(domain string, wildcard bool, records []*dns.CAA) Problem {
return Problem{
Name: "CAACriticalUnknown",
Explanation: fmt.Sprintf(`CAA record(s) exist on %s (wildcard=%t) that are marked as critical but are unknown to Let's Encrypt. `+
`These record(s) as shown in the detail must be removed, or marked as non-critical, before a certificate can be issued by the Let's Encrypt CA.`, domain, wildcard),
Detail: collateRecords(records),
Severity: SeverityFatal,
}
}
func caaIssuanceNotAllowed(domain string, wildcard bool, records []*dns.CAA) Problem {
return Problem{
Name: "CAAIssuanceNotAllowed",
Explanation: fmt.Sprintf(`No CAA record on %s (wildcard=%t) contains the issuance domain "letsencrypt.org". `+
`You must either add an additional record to include "letsencrypt.org" or remove every existing CAA record. `+
`A list of the CAA records are provided in the details.`, domain, wildcard),
Detail: collateRecords(records),
Severity: SeverityFatal,
}
}
func invalidDomain(domain, reason string) Problem {
return Problem{
Name: "InvalidDomain",
Explanation: fmt.Sprintf(`"%s" is not a valid domain name that Let's Encrypt would be able to issue a certificate for.`, domain),
Detail: reason,
Severity: SeverityFatal,
}
}
// cloudflareChecker determines if the domain is using cloudflare, and whether a certificate has been provisioned by cloudflare yet.
type cloudflareChecker struct{}
func (c cloudflareChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
if method == DNS01 {
return nil, errNotApplicable
}
var probs []Problem
domain = strings.TrimPrefix(domain, "*.")
cl := http.Client{
Timeout: httpTimeout * time.Second,
Transport: makeSingleShotHTTPTransport(),
CheckRedirect: func(req *http.Request, via []*http.Request) error {
// Disasble redirects
return http.ErrUseLastResponse
},
}
resp, err := cl.Get("https://" + domain)
if err == nil { // no tls error, cert must be issued
// check if it's cloudflare
if hasCloudflareHeader(resp.Header) {
probs = append(probs, cloudflareCDN(domain, method))
}
return probs, nil
}
// attempt to connect over http with redirects disabled to check cloudflare header
resp, err = cl.Get("http://" + domain)
if err != nil {
return probs, nil
}
if hasCloudflareHeader(resp.Header) {
probs = append(probs, cloudflareCDN(domain, method))
probs = append(probs, cloudflareSslNotProvisioned(domain))
}
return probs, nil
}
func hasCloudflareHeader(h http.Header) bool {
return strings.Contains(strings.ToLower(h.Get("server")), "cloudflare")
}
func cloudflareCDN(domain string, method ValidationMethod) Problem {
if method == TLSALPN01 {
return Problem{
Name: "CloudflareCDN",
Explanation: fmt.Sprintf(`The domain %s is being served through Cloudflare CDN, `+
`which supports the HTTP & HTTPS protocols only. It is impossible to obtain a `+
`certificate using the TLS-ALPN-01 challenge with the Cloudflare CDN proxy enabled.`, domain),
Severity: SeverityFatal,
}
}
return Problem{
Name: "CloudflareCDN",
Explanation: fmt.Sprintf(`The domain %s is being served through Cloudflare CDN. Any Let's Encrypt certificate installed on the `+
`origin server will only encrypt traffic between the server and Cloudflare. It is strongly recommended that the SSL option 'Full SSL (strict)' `+
`be enabled.`, domain),
Detail: "https://support.cloudflare.com/hc/en-us/articles/200170416-What-do-the-SSL-options-mean-",
Severity: SeverityWarning,
}
}
func cloudflareSslNotProvisioned(domain string) Problem {
return Problem{
Name: "CloudflareSSLNotProvisioned",
Explanation: fmt.Sprintf(`The domain %s is being served through Cloudflare CDN and a certificate has not yet been provisioned yet by Cloudflare.`, domain),
Detail: "https://support.cloudflare.com/hc/en-us/articles/203045244-How-long-does-it-take-for-Cloudflare-s-SSL-to-activate-",
Severity: SeverityWarning,
}
}
// statusioChecker ensures there is no reported operational problem with the Let's Encrypt service via the status.io public api.
type statusioChecker struct{}
// statusioSignificantStatuses denotes which statuses warrant raising a warning.
// 100 (operational) and 200 (undocumented but assume "Planned Maintenance") should not be included.
// https://kb.status.io/developers/status-codes/
var statusioSignificantStatuses = map[int]bool{
300: true, // Degraded Performance
400: true, // Partial Service Disruption
500: true, // Service Disruption
600: true, // Security Event
}
func (c statusioChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
var probs []Problem
resp, err := http.Get("https://api.status.io/1.0/status/55957a99e800baa4470002da")
if err != nil {
// some connectivity errors with status.io is probably not worth reporting
return probs, nil
}
defer resp.Body.Close()
apiResp := struct {
Result struct {
StatusOverall struct {
Updated time.Time `json:"updated"`
Status string `json:"status"`
StatusCode int `json:"status_code"`
} `json:"status_overall"`
} `json:"result"`
}{}
if err := json.NewDecoder(resp.Body).Decode(&apiResp); err != nil {
return probs, fmt.Errorf("error decoding status.io api response: %v", err)
}
if statusioSignificantStatuses[apiResp.Result.StatusOverall.StatusCode] {
probs = append(probs, statusioNotOperational(apiResp.Result.StatusOverall.Status, apiResp.Result.StatusOverall.Updated))
}
probs = append(probs, debugProblem("StatusIO", "The current status.io status for Let's Encrypt",
fmt.Sprintf("%v", apiResp.Result.StatusOverall.Status)))
return probs, nil
}
func statusioNotOperational(status string, updated time.Time) Problem {
return Problem{
Name: "StatusNotOperational",
Explanation: fmt.Sprintf(`The current status as reported by the Let's Encrypt status page is %s as at %v. `+
`Depending on the reported problem, this may affect certificate issuance. For more information, please visit the status page.`, status, updated),
Detail: "https://letsencrypt.status.io/",
Severity: SeverityInfo,
}
}
type crtList map[string]*x509.Certificate
// FindCommonPSLCertificates finds any certificates which contain any DNSName
// that shares the Registered Domain `registeredDomain`.
func (l crtList) FindWithCommonRegisteredDomain(registeredDomain string) sortedCertificates {
var out sortedCertificates
for _, cert := range l {
for _, name := range cert.DNSNames {
if nameRegDomain, _ := publicsuffix.EffectiveTLDPlusOne(name); nameRegDomain == registeredDomain {
out = append(out, cert)
break
}
}
}
sort.Sort(out)
return out
}
func (l crtList) GetOldestCertificate() *x509.Certificate {
var oldest *x509.Certificate
for _, crt := range l {
if oldest == nil || crt.NotBefore.Before(oldest.NotBefore) {
oldest = crt
}
}
return oldest
}
// CountDuplicates counts how many duplicate certificates there are
// that also contain the name `domain`
func (l crtList) CountDuplicates(domain string) map[string]int {
counts := map[string]int{}
for _, cert := range l {
found := false
for _, name := range cert.DNSNames {
if name == domain {
found = true
break
}
}
if !found {
continue
}
names := make([]string, len(cert.DNSNames))
copy(names, cert.DNSNames)
sort.Strings(names)
k := strings.Join(names, ",")
counts[k]++
}
return counts
}
// rateLimitChecker ensures that the domain is not currently affected
// by domain-based rate limits using crtwatch's database
type rateLimitChecker struct {
}
type sortedCertificates []*x509.Certificate
func (certs sortedCertificates) Len() int { return len(certs) }
func (certs sortedCertificates) Swap(i, j int) { certs[i], certs[j] = certs[j], certs[i] }
func (certs sortedCertificates) Less(i, j int) bool {
return certs[j].NotBefore.Before(certs[i].NotBefore)
}
const rateLimitCheckerQuery = `
WITH ci AS
(SELECT min(sub.CERTIFICATE_ID) ID,
min(sub.ISSUER_CA_ID) ISSUER_CA_ID,
sub.CERTIFICATE DER
FROM
(SELECT *
FROM certificate_and_identities cai
WHERE plainto_tsquery('%s') @@ identities(cai.CERTIFICATE)
AND cai.NAME_VALUE ILIKE ('%%%s%%')
AND x509_notBefore(cai.CERTIFICATE) >= '%s'
AND cai.issuer_ca_id IN (16418, 183267, 183283)
LIMIT 1000) sub
GROUP BY sub.CERTIFICATE)
SELECT ci.DER der
FROM ci
LEFT JOIN LATERAL
(SELECT min(ctle.ENTRY_TIMESTAMP) ENTRY_TIMESTAMP
FROM ct_log_entry ctle
WHERE ctle.CERTIFICATE_ID = ci.ID ) le ON TRUE,
ca
WHERE ci.ISSUER_CA_ID = ca.ID
ORDER BY le.ENTRY_TIMESTAMP DESC;`
// Pointer receiver because we're keeping state across runs
func (c *rateLimitChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
if os.Getenv("LETSDEBUG_DISABLE_CERTWATCH") != "" {
return nil, errNotApplicable
}
domain = strings.TrimPrefix(domain, "*.")
db, err := sql.Open("postgres", "user=guest dbname=certwatch host=crt.sh sslmode=disable connect_timeout=5")
if err != nil {
return []Problem{
internalProblem(fmt.Sprintf("Failed to connect to certwatch database to check rate limits: %v", err), SeverityDebug),
}, nil
}
defer db.Close()
// Since we are checking rate limits, we need to query the Registered Domain
// for the domain in question
registeredDomain, _ := publicsuffix.EffectiveTLDPlusOne(domain)
timeoutCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
// Avoiding using a prepared statement here because it's being weird with crt.sh
q := fmt.Sprintf(rateLimitCheckerQuery,
registeredDomain, registeredDomain, time.Now().Add(-168*time.Hour).Format(time.RFC3339))
rows, err := db.QueryContext(timeoutCtx, q)
if err != nil && err != sql.ErrNoRows {
return []Problem{
internalProblem(fmt.Sprintf("Failed to query certwatch database to check rate limits: %v", err), SeverityDebug),
}, nil
}
probs := []Problem{}
// Read in the DER-encoded certificates
certs := crtList{}
var certBytes []byte
for rows.Next() {
if err := rows.Scan(&certBytes); err != nil {
probs = append(probs, internalProblem(fmt.Sprintf("Failed to query certwatch database while checking rate limits: %v", err), SeverityDebug))
break
}
crt, err := x509.ParseCertificate(certBytes)
if err != nil {
probs = append(probs, internalProblem(fmt.Sprintf("Failed to parse certificate while checking rate limits: %v", err), SeverityDebug))
continue
}
certs[crt.SerialNumber.String()] = crt
}
if err := rows.Err(); err != nil {
return []Problem{
internalProblem(fmt.Sprintf("Failed to query certwatch database to check rate limits: %v", err), SeverityDebug),
}, nil
}
var debug string
// Limit: Certificates per Registered Domain
// TODO: implement Renewal Exemption
certsTowardsRateLimit := certs.FindWithCommonRegisteredDomain(registeredDomain)
if len(certs) > 0 && len(certsTowardsRateLimit) >= 50 {
dropOff := certs.GetOldestCertificate().NotBefore.Add(7 * 24 * time.Hour)
dropOffDiff := time.Until(dropOff).Truncate(time.Minute)
probs = append(probs, rateLimited(domain, fmt.Sprintf("The 'Certificates per Registered Domain' limit ("+
"50 certificates per week that share the same Registered Domain: %s) has been exceeded. "+
"There is no way to work around this rate limit. "+
"The next non-renewal certificate for this Registered Domain should be issuable after %v (%v from now).",
registeredDomain, dropOff, dropOffDiff)))
}
for _, cert := range certsTowardsRateLimit {
debug = fmt.Sprintf("%s\nSerial: %s\nNotBefore: %v\nNames: %v\n", debug, cert.SerialNumber.String(), cert.NotBefore, cert.DNSNames)
}
// Limit: Duplicate Certificate limit of 5 certificates per week
for names, dupes := range certs.CountDuplicates(domain) {
if dupes < 5 {
continue
}
probs = append(probs, rateLimited(domain,
fmt.Sprintf(`The Duplicate Certificate limit (5 certificates with the exact same set of domains per week) has been `+
`exceeded and is affecting the domain "%s". The exact set of domains affected is: "%v". It may be possible to avoid this `+
`rate limit by issuing a certificate with an additional or different domain name.`, domain, names)))
}
if debug != "" {
probs = append(probs, debugProblem("RateLimit",
fmt.Sprintf("%d Certificates contributing to rate limits for this domain", len(certsTowardsRateLimit)), debug))
}
return probs, nil
}
func rateLimited(domain, detail string) Problem {
registeredDomain, _ := publicsuffix.EffectiveTLDPlusOne(domain)
return Problem{
Name: "RateLimit",
Explanation: fmt.Sprintf(`%s is currently affected by Let's Encrypt-based rate limits (https://letsencrypt.org/docs/rate-limits/). `+
`You may review certificates that have already been issued by visiting https://crt.sh/?q=%%%s . `+
`Please note that it is not possible to ask for a rate limit to be manually cleared.`, domain, registeredDomain),
Detail: detail,
Severity: SeverityError,
}
}
var (
stagingFailures = promauto.NewCounterVec(
prometheus.CounterOpts{
Namespace: "letsdebug",
Name: "staging_tests_failed_total",
Help: "The total number of Let's Encrypt staging submissions encountering internal errors",
},
[]string{"method"})
)
// acmeStagingChecker tries to create an authorization on
// Let's Encrypt's staging server and parse the error urn
// to see if there's anything interesting reported.
type acmeStagingChecker struct {
client acme.Client
account acme.Account
clientMu sync.Mutex
}
func ConfigureAcmeClient() acme.OptionFunc {
return func(client *acme.Client) error {
// Give the ACME CA more time to complete challenges
client.PollTimeout = time.Minute * 3
return nil
}
}
func (c *acmeStagingChecker) buildAcmeClient() error {
cl, err := acme.NewClient("https://acme-staging-v02.api.letsencrypt.org/directory", ConfigureAcmeClient())
if err != nil {
return err
}
regrPath := os.Getenv("LETSDEBUG_ACMESTAGING_ACCOUNTFILE")
if regrPath == "" {
regrPath = "acme-account.json"
}
buf, err := os.ReadFile(regrPath)
if err != nil {
return err
}
var out struct {
PEM string `json:"pem"`
URL string `json:"url"`
}
if err := json.Unmarshal(buf, &out); err != nil {
return err
}
block, _ := pem.Decode([]byte(out.PEM))
pk, err := x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
return err
}
c.account = acme.Account{PrivateKey: pk, URL: out.URL}
c.client = cl
return nil
}
func (c *acmeStagingChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
if os.Getenv("LETSDEBUG_DISABLE_ACMESTAGING") != "" {
return nil, errNotApplicable
}
c.clientMu.Lock()
if c.account.PrivateKey == nil {
if err := c.buildAcmeClient(); err != nil {
c.clientMu.Unlock()
stagingFailures.With(prometheus.Labels{"method": string(method)}).Inc()
return []Problem{
internalProblem(fmt.Sprintf("Couldn't setup Let's Encrypt staging checker, skipping: %v", err), SeverityWarning),
}, nil
}
}
c.clientMu.Unlock()
probs := []Problem{}
order, err := c.client.NewOrder(c.account, []acme.Identifier{{Type: "dns", Value: domain}})
if err != nil {
if p, stagingBroken := translateAcmeError(domain, err); p.Name != "" {
if stagingBroken {
stagingFailures.With(prometheus.Labels{"method": string(method)}).Inc()
}
probs = append(probs, p)
}
probs = append(probs, debugProblem("LetsEncryptStaging", "Order creation error", err.Error()))
return probs, nil
}
// A real ACME client would now set up some challenges (by placing files, configuring webservers, talking to DNS).
// This takes a short while. However, we can technically query the ACME server right away. But, that may cause races
// within Let's Encrypts code, because our subsequent requests could end up hitting a replica which hasn't synced the
// new authz URLs yet. So, wait a moment to simulate a real ACME client doing work.
time.Sleep(3 * time.Second)
var wg sync.WaitGroup
wg.Add(len(order.Authorizations))
var probsMu sync.Mutex
unhandledError := func(err error) {
probsMu.Lock()
defer probsMu.Unlock()
stagingFailures.With(prometheus.Labels{"method": string(method)}).Inc()
probs = append(probs, internalProblem("An unknown problem occurred while performing a test "+
"authorization against the Let's Encrypt staging service: "+err.Error(), SeverityWarning))
}
authzFailures := []string{}
for _, authzURL := range order.Authorizations {
go func(authzURL string) {
defer wg.Done()
authz, err := c.client.FetchAuthorization(c.account, authzURL)
if err != nil {
if p, stagingBroken := translateAcmeError(domain, err); p.Name != "" {
if stagingBroken {
stagingFailures.With(prometheus.Labels{"method": string(method)}).Inc()
}
probs = append(probs, p)
} else {
unhandledError(err)
}
return
}
chal, ok := authz.ChallengeMap[string(method)]
if !ok {
// TODO: we sometimes run into this if an authorization is reused
unhandledError(fmt.Errorf("Missing challenge method (want %v): %v", method, authz.ChallengeMap))
return
}
if _, err := c.client.UpdateChallenge(c.account, chal); err != nil {
probsMu.Lock()
if p, stagingBroken := translateAcmeError(domain, err); p.Name != "" {
if stagingBroken {
stagingFailures.With(prometheus.Labels{"method": string(method)}).Inc()
}
probs = append(probs, p)
}
authzFailures = append(authzFailures, err.Error())
probsMu.Unlock()
}
}(authzURL)
}
wg.Wait()
if len(authzFailures) > 0 {
probs = append(probs, debugProblem("LetsEncryptStaging",
fmt.Sprintf("Challenge update failures for %s in order %s", domain, order.URL),
strings.Join(authzFailures, "\n")))
} else {
probs = append(probs, debugProblem("LetsEncryptStaging", "Order for "+domain, order.URL))
}
return probs, nil
}
func translateAcmeError(domain string, err error) (problem Problem, stagingBroken bool) {
var acmeErr acme.Problem
if errors.As(err, &acmeErr) {
urn := strings.TrimPrefix(acmeErr.Type, "urn:ietf:params:acme:error:")
switch urn {
case "rejectedIdentifier", "unknownHost", "rateLimited", "caa", "dns", "connection":
if strings.Contains(acmeErr.Detail, "Service busy; retry later") {
return infoProblem("ServiceBusy", "The Let's Encrypt staging service refused our request for a test dry-run. The test outputs may not be accurate. Please retry the test at a later time.", "Let's Encrypt Staging Sever busy."), true
}
// Boulder can send error:dns when _acme-challenge is NXDOMAIN, which is
// equivalent to unauthorized
if strings.Contains(acmeErr.Detail, "NXDOMAIN looking up TXT") {
return Problem{}, false
}
return letsencryptProblem(domain, acmeErr.Detail, SeverityError), false
// When something bad is happening on staging
case "serverInternal":
return letsencryptProblem(domain,
fmt.Sprintf(`There may be internal issues on the staging service: %v`, acmeErr.Detail), SeverityWarning), true
// Unauthorized is what we expect, except for these exceptions that we should handle:
// - When VA OR RA is checking Google Safe Browsing (groan)
case "unauthorized":
if strings.Contains(acmeErr.Detail, "considered an unsafe domain") {
return letsencryptProblem(domain, acmeErr.Detail, SeverityError), false
}
return Problem{}, false
default:
return Problem{}, false
}
}
return internalProblem(fmt.Sprintf("An unknown issue occurred when performing a test authorization "+
"against the Let's Encrypt staging service: %v", err), SeverityWarning), true
}
func letsencryptProblem(domain, detail string, severity SeverityLevel) Problem {
return Problem{
Name: "IssueFromLetsEncrypt",
Explanation: fmt.Sprintf(`A test authorization for %s to the Let's Encrypt staging service has revealed `+
`issues that may prevent any certificate for this domain being issued.`, domain),
Detail: detail,
Severity: severity,
}
}
// ofacSanctionChecker checks whether a Registered Domain is present on the the XML sanctions list
// (https://www.treasury.gov/ofac/downloads/sdn.xml).
// It is disabled by default, and must be enabled with the environment variable LETSDEBUG_ENABLE_OFAC=1
type ofacSanctionChecker struct {
muRefresh sync.RWMutex
domains map[string]struct{}
}
func (c *ofacSanctionChecker) Check(ctx *scanContext, domain string, method ValidationMethod) ([]Problem, error) {
if os.Getenv("LETSDEBUG_ENABLE_OFAC") != "1" {
return nil, errNotApplicable
}
c.muRefresh.RLock()
defer c.muRefresh.RUnlock()
rd, _ := publicsuffix.EffectiveTLDPlusOne(domain)
for sanctionedRD := range c.domains {
if rd != sanctionedRD {
continue
}
return []Problem{{
Name: "SanctionedDomain",
Explanation: fmt.Sprintf("The Registered Domain %s was found on the United States' OFAC "+
"Specially Designated Nationals and Blocked Persons (SDN) List. Let's Encrypt are unable to issue certificates "+
"for sanctioned entities. Search on https://sanctionssearch.ofac.treas.gov/ for futher details.", sanctionedRD),
Severity: SeverityError,
}}, nil
}
return nil, nil
}
func (c *ofacSanctionChecker) setup() {
if os.Getenv("LETSDEBUG_ENABLE_OFAC") != "1" {
return
}
c.domains = map[string]struct{}{}
go func() {
for {
if err := c.poll(); err != nil {
fmt.Printf("OFAC SDN poller failed: %v\n", err)
}
time.Sleep(24 * time.Hour)
}
}()
}
func (c *ofacSanctionChecker) poll() error {
req, _ := http.NewRequest(http.MethodGet, "https://www.treasury.gov/ofac/downloads/sdn.xml", nil)
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
req = req.WithContext(ctx)
req.Header.Set("User-Agent", "Let's Debug (https://letsdebug.net)")
resp, err := http.DefaultClient.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
dec := xml.NewDecoder(resp.Body)
registeredDomains := map[string]struct{}{}
isID := false
for {
tok, _ := dec.Token()
if tok == nil {
break
}
switch el := tok.(type) {
case xml.StartElement:
if el.Name.Local == "id" {
isID = true
break
}
if el.Name.Local == "idType" {
next, _ := dec.Token()
if next == nil {
break
}
raw, ok := next.(xml.CharData)
if !ok {
break
}
if string(raw) != "Website" {
isID = false
break
}
break
}
if el.Name.Local == "idNumber" && isID {
next, _ := dec.Token()
if next == nil {
break
}
raw, ok := next.(xml.CharData)
if !ok {
break
}
if rd := c.extractRegisteredDomain(string(raw)); rd != "" {
registeredDomains[rd] = struct{}{}
}
}
case xml.EndElement:
if el.Name.Local == "id" {
isID = false
break
}
}
}
c.muRefresh.Lock()
defer c.muRefresh.Unlock()
c.domains = registeredDomains
return nil
}