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mirror of https://github.com/go-acme/lego.git synced 2024-12-05 12:00:24 +02:00

ACME HTTP: Allow customizing HTTP client x509.CertPool (#571)

This commit updates `acme/http.go` to allow customizing the
`*x509.CertPool` used by the `HTTPClient` by specifying the filepath of
a custom CA certificate via the `CA_CERTIFICATE` environment variable.

This allows developers to easily trust a non-standard CA when
interacting with an ACME test server (e.g. Pebble):

```
CA_CERTIFICATE=~/go/src/github.com/letsencrypt/pebble/test/certs/pebble.minica.pem \
lego \
  --server https://localhost:14000/dir \
  --email foo@bar.com \
  -d example.com \
  run
```
This commit is contained in:
Daniel McCarney 2018-06-11 09:45:59 -04:00 committed by Ludovic Fernandez
parent 5005315fff
commit 8f9e90b2a0
2 changed files with 164 additions and 15 deletions

View File

@ -1,33 +1,44 @@
package acme
import (
"crypto/tls"
"crypto/x509"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"os"
"runtime"
"strings"
"time"
)
// UserAgent (if non-empty) will be tacked onto the User-Agent string in requests.
var UserAgent string
var (
// UserAgent (if non-empty) will be tacked onto the User-Agent string in requests.
UserAgent string
// HTTPClient is an HTTP client with a reasonable timeout value.
var HTTPClient = http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 15 * time.Second,
ResponseHeaderTimeout: 15 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
},
}
// HTTPClient is an HTTP client with a reasonable timeout value and
// potentially a custom *x509.CertPool based on the caCertificatesEnvVar
// environment variable (see the `initCertPool` function)
HTTPClient = http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 15 * time.Second,
ResponseHeaderTimeout: 15 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
TLSClientConfig: &tls.Config{
RootCAs: initCertPool(),
},
},
}
)
const (
// defaultGoUserAgent is the Go HTTP package user agent string. Too
@ -36,8 +47,36 @@ const (
// ourUserAgent is the User-Agent of this underlying library package.
ourUserAgent = "xenolf-acme"
// caCertificatesEnvVar is the environment variable name that can be used to
// specify the path to PEM encoded CA Certificates that can be used to
// authenticate an ACME server with a HTTPS certificate not issued by a CA in
// the system-wide trusted root list.
caCertificatesEnvVar = "LEGO_CA_CERTIFICATES"
)
// initCertPool creates a *x509.CertPool populated with the PEM certificates
// found in the filepath specified in the caCertificatesEnvVar OS environment
// variable. If the caCertificatesEnvVar is not set then initCertPool will
// return nil. If there is an error creating a *x509.CertPool from the provided
// caCertificatesEnvVar value then initCertPool will panic.
func initCertPool() *x509.CertPool {
if customCACertsPath := os.Getenv(caCertificatesEnvVar); customCACertsPath != "" {
customCAs, err := ioutil.ReadFile(customCACertsPath)
if err != nil {
panic(fmt.Sprintf("error reading %s=%q: %v",
caCertificatesEnvVar, customCACertsPath, err))
}
certPool := x509.NewCertPool()
if ok := certPool.AppendCertsFromPEM(customCAs); !ok {
panic(fmt.Sprintf("error creating x509 cert pool from %s=%q: %v",
caCertificatesEnvVar, customCACertsPath, err))
}
return certPool
}
return nil
}
// httpHead performs a HEAD request with a proper User-Agent string.
// The response body (resp.Body) is already closed when this function returns.
func httpHead(url string) (resp *http.Response, err error) {

View File

@ -1,8 +1,10 @@
package acme
import (
"io/ioutil"
"net/http"
"net/http/httptest"
"os"
"strings"
"testing"
)
@ -98,3 +100,111 @@ func TestUserAgent(t *testing.T) {
t.Errorf("Expected custom UA to contain %s, got '%s'", UserAgent, ua)
}
}
// TestInitCertPool tests the http.go initCertPool function for customizing the
// HTTP Client *x509.CertPool with an environment variable.
func TestInitCertPool(t *testing.T) {
// writeTemp creates a temp file with the given contents & prefix and returns
// the file path. If an error occurs, t.Fatalf is called to end the test run.
writeTemp := func(t *testing.T, contents, prefix string) string {
t.Helper()
tmpFile, err := ioutil.TempFile("", prefix)
if err != nil {
t.Fatalf("Unable to create tempfile: %v", err)
}
err = ioutil.WriteFile(tmpFile.Name(), []byte(contents), 0700)
if err != nil {
t.Fatalf("Unable to write tempfile contents: %v", err)
}
return tmpFile.Name()
}
invalidFileContents := "not a certificate"
invalidFile := writeTemp(t, invalidFileContents, "invalid.pem")
// validFileContents is lifted from Pebble[0]. Generate your own CA cert with
// MiniCA[1].
// [0]: https://github.com/letsencrypt/pebble/blob/de6fa233ea1f283eeb9751d42c8e1ae72718c44e/test/certs/pebble.minica.pem
// [1]: https://github.com/jsha/minica
validFileContents := `
-----BEGIN CERTIFICATE-----
MIIDCTCCAfGgAwIBAgIIJOLbes8sTr4wDQYJKoZIhvcNAQELBQAwIDEeMBwGA1UE
AxMVbWluaWNhIHJvb3QgY2EgMjRlMmRiMCAXDTE3MTIwNjE5NDIxMFoYDzIxMTcx
MjA2MTk0MjEwWjAgMR4wHAYDVQQDExVtaW5pY2Egcm9vdCBjYSAyNGUyZGIwggEi
MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC5WgZNoVJandj43kkLyU50vzCZ
alozvdRo3OFiKoDtmqKPNWRNO2hC9AUNxTDJco51Yc42u/WV3fPbbhSznTiOOVtn
Ajm6iq4I5nZYltGGZetGDOQWr78y2gWY+SG078MuOO2hyDIiKtVc3xiXYA+8Hluu
9F8KbqSS1h55yxZ9b87eKR+B0zu2ahzBCIHKmKWgc6N13l7aDxxY3D6uq8gtJRU0
toumyLbdzGcupVvjbjDP11nl07RESDWBLG1/g3ktJvqIa4BWgU2HMh4rND6y8OD3
Hy3H8MY6CElL+MOCbFJjWqhtOxeFyZZV9q3kYnk9CAuQJKMEGuN4GU6tzhW1AgMB
AAGjRTBDMA4GA1UdDwEB/wQEAwIChDAdBgNVHSUEFjAUBggrBgEFBQcDAQYIKwYB
BQUHAwIwEgYDVR0TAQH/BAgwBgEB/wIBADANBgkqhkiG9w0BAQsFAAOCAQEAF85v
d40HK1ouDAtWeO1PbnWfGEmC5Xa478s9ddOd9Clvp2McYzNlAFfM7kdcj6xeiNhF
WPIfaGAi/QdURSL/6C1KsVDqlFBlTs9zYfh2g0UXGvJtj1maeih7zxFLvet+fqll
xseM4P9EVJaQxwuK/F78YBt0tCNfivC6JNZMgxKF59h0FBpH70ytUSHXdz7FKwix
Mfn3qEb9BXSk0Q3prNV5sOV3vgjEtB4THfDxSz9z3+DepVnW3vbbqwEbkXdk3j82
2muVldgOUgTwK8eT+XdofVdntzU/kzygSAtAQwLJfn51fS1GvEcYGBc1bDryIqmF
p9BI7gVKtWSZYegicA==
-----END CERTIFICATE-----
`
validFile := writeTemp(t, validFileContents, "valid.pem")
testCases := []struct {
Name string
EnvVar string
ExpectPanic bool
ExpectNil bool
}{
// Setting the env var to a file that doesn't exist should panic
{
Name: "Env var with missing file",
EnvVar: "not.a.real.file.pem",
ExpectPanic: true,
},
// Setting the env var to a file that contains invalid content should panic
{
Name: "Env var with invalid content",
EnvVar: invalidFile,
ExpectPanic: true,
},
// Setting the env var to the empty string should not panic and should
// return nil
{
Name: "No env var",
EnvVar: "",
ExpectPanic: false,
ExpectNil: true,
},
// Setting the env var to a file that contains valid content should not
// panic and should not return nil
{
Name: "Env var with valid content",
EnvVar: validFile,
ExpectPanic: false,
ExpectNil: false,
},
}
for _, tc := range testCases {
t.Run(tc.Name, func(t *testing.T) {
os.Setenv(caCertificatesEnvVar, tc.EnvVar)
defer os.Setenv(caCertificatesEnvVar, "")
defer func() {
if r := recover(); r == nil && tc.ExpectPanic {
t.Errorf("expected initCertPool() to panic, it did not")
} else if r != nil && !tc.ExpectPanic {
t.Errorf("expected initCertPool() to not panic, but it did")
}
}()
result := initCertPool()
if result == nil && !tc.ExpectNil {
t.Errorf("initCertPool() returned nil, expected non-nil")
} else if result != nil && tc.ExpectNil {
t.Errorf("initCertPool() returned non-nil, expected nil")
}
})
}
}