Adding generation of cert and key, and dockerfile

This commit is contained in:
PierreZ 2015-07-19 15:11:03 +02:00
parent 38fe333888
commit 60df40beb9
5 changed files with 167 additions and 37 deletions

4
Dockerfile Normal file
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@ -0,0 +1,4 @@
FROM centurylink/ca-certs
COPY goStatic /
ENTRYPOINT ["/goStatic"]

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@ -1,4 +1,4 @@
default: static
static:
docker run --rm -v $(pwd):/src centurylink/golang-builder
docker run --rm -v $(shell pwd):/src centurylink/golang-builder

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@ -4,17 +4,42 @@ A really small static web server for Docker
### The goal
My goal is to create to smallest docker container for my web static files. The advantage of Go is that you can generate a fully static binary, so that you don't need anything else.
### Features
* Web server build for Docker
* HTTPS by default
* Can generate certificate on his onw
* Light container
* More security than official images (see below)
* Log enabled
### Why?
Because the official Golang image is wayyyy to big. (around 1/2Gb as you can see below)
Because the official Golang image is wayyyy to big (around 1/2Gb as you can see below) and could be unsecure.
[![](https://badge.imagelayers.io/golang:latest.svg)](https://imagelayers.io/?images=golang:latest 'Get your own badge on imagelayers.io')
For me, the whole point of containers is to have a light container...
Many links should provide you with additionnal info to see my point of view:
* [Over 30% of Official Images in Docker Hub Contain High Priority Security Vulnerabilities](http://www.banyanops.com/blog/analyzing-docker-hub/)
* [Create The Smallest Possible Docker Container](http://blog.xebia.com/2014/07/04/create-the-smallest-possible-docker-container/)
* [Building Docker Images for Static Go Binaries](https://medium.com/@kelseyhightower/optimizing-docker-images-for-static-binaries-b5696e26eb07)
* [Small Docker Images For Go Apps](http://www.centurylinklabs.com/small-docker-images-for-go-apps/)
### What are you using?
### How to use
```
// HTTPS server
docker run -d -p 443:8043 -v path/to/website:/srv/http pierrezemb/goStatic
// HTTP server
docker run -d -p 80:8043 -v path/to/website:/srv/http pierrezemb/goStatic --forceHTTP
```
I'm using [echo](http://echo.labstack.com/) as a micro web framework because he has great performance, and [golang-builder](https://github.com/CenturyLinkLabs/golang-builder) to generate the static binary.
### Wow, such container! What are you using?
I'm using [echo](http://echo.labstack.com/) as a micro web framework because he has great performance, and [golang-builder](https://github.com/CenturyLinkLabs/golang-builder) to generate the static binary (command line in the makefile)
I'm also using the centurylink/ca-certs image instead of the scratch image to avoid this error:
```
x509: failed to load system roots and no roots provided
```
The centurylink/ca-certs image is simply the scratch image with the most common root CA certificates pre-installed. The resulting image is only 258 kB which is still a good starting point for creating your own minimal images.

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goStatic Executable file

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167
main.go
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@ -1,6 +1,8 @@
package main // import "github.com/PierreZ/goStatic"
import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
@ -8,23 +10,35 @@ import (
"encoding/pem"
"flag"
"fmt"
"io/ioutil"
"log"
"math/big"
"net"
"os"
"strconv"
"strings"
"time"
"github.com/labstack/echo"
mw "github.com/labstack/echo/middleware"
)
func main() {
var (
// Def & parsing of flags
portPtr := flag.Int("p", 8080, "The proxy listening port")
pathPtr := flag.String("path for static file", "/var/www", "The path for the static files")
crtPtr := flag.String("crt", "/etc/ssl/server", "The path and the name whithout extension for your CRT/key for TLS. Example: /etc/ssl/server for /etc/ssl/server.{crt,key}")
HTTPPtr := flag.Bool("forceHTTP", false, "Forcing HTTP and not HTTPS")
portPtr = flag.Int("p", 8043, "The listening port")
pathPtr = flag.String("static", "/srv/http", "The path for the static files")
crtPtr = flag.String("crt", "/etc/ssl/server", "Folder for server.pem and key.pem")
HTTPPtr = flag.Bool("forceHTTP", false, "Forcing HTTP and not HTTPS")
// var for cert
host = flag.String("host", "", "Comma-separated hostnames and IPs to generate a certificate for")
validFrom = flag.String("start-date", "", "Creation date formatted as Jan 1 15:04:05 2011")
validFor = flag.Duration("duration", 365*24*time.Hour, "Duration that certificate is valid for")
isCA = flag.Bool("ca", false, "whether this cert should be its own Certificate Authority")
rsaBits = flag.Int("rsa-bits", 2048, "Size of RSA key to generate. Ignored if --ecdsa-curve is set")
ecdsaCurve = flag.String("ecdsa-curve", "", "ECDSA curve to use to generate a key. Valid values are P224, P256, P384, P521")
)
func main() {
flag.Parse()
@ -45,54 +59,141 @@ func main() {
// Start server with unsecure HTTP
// or with awesome TLS
if *HTTPPtr {
log.Println("Starting serving", *pathPtr, "on", *portPtr)
e.Run(port)
} else {
if *crtPtr != "/etc/ssl/server" {
// Check for cert
_, err := os.Stat(*crtPtr + "cert.pem")
if err != nil {
log.Println("Cert not found, generating .pem and .crt file")
generateCert(*crtPtr)
}
e.RunTLS(port, *pathPtr+".pem", *pathPtr+".crt")
log.Println("Starting serving", *pathPtr, "on", *portPtr)
e.RunTLS(port, *crtPtr+"cert.pem", *crtPtr+"key.pem")
}
}
// Mostly based on https://www.socketloop.com/tutorials/golang-create-x509-certificate-private-and-public-keys
// Based on https://golang.org/src/crypto/tls/generate_cert.go
func generateCert(path string) {
var priv interface{}
var err error
switch *ecdsaCurve {
case "":
priv, err = rsa.GenerateKey(rand.Reader, *rsaBits)
case "P224":
priv, err = ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
case "P256":
priv, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
case "P384":
priv, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
case "P521":
priv, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
default:
fmt.Fprintf(os.Stderr, "Unrecognized elliptic curve: %q", *ecdsaCurve)
os.Exit(1)
}
if err != nil {
log.Fatalf("failed to generate private key: %s", err)
}
template := &x509.Certificate{
IsCA: true,
BasicConstraintsValid: true,
SubjectKeyId: []byte{1, 2, 3},
SerialNumber: big.NewInt(1234),
var notBefore time.Time
if len(*validFrom) == 0 {
notBefore = time.Now()
} else {
notBefore, err = time.Parse("Jan 2 15:04:05 2006", *validFrom)
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to parse creation date: %s\n", err)
os.Exit(1)
}
}
notAfter := notBefore.Add(*validFor)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
log.Fatalf("failed to generate serial number: %s", err)
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Country: []string{"Earth"},
Organization: []string{"Hooli"},
},
NotBefore: time.Now(),
NotAfter: time.Now().AddDate(5, 5, 5),
// see http://golang.org/pkg/crypto/x509/#KeyUsage
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth},
KeyUsage: x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
// generate private key
privatekey, err := rsa.GenerateKey(rand.Reader, 4096)
hosts := strings.Split(*host, ",")
for _, h := range hosts {
if ip := net.ParseIP(h); ip != nil {
template.IPAddresses = append(template.IPAddresses, ip)
} else {
template.DNSNames = append(template.DNSNames, h)
}
}
if *isCA {
template.IsCA = true
template.KeyUsage |= x509.KeyUsageCertSign
}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
if err != nil {
log.Println(err)
log.Fatalf("Failed to create certificate: %s", err)
}
// save cert
ioutil.WriteFile(path+".crt", cert, 0777)
fmt.Println("certificate saved to", path+".crt")
certOut, err := os.Create(path + "cert.pem")
if err != nil {
log.Fatalf("failed to open cert.pem for writing: %s", err)
}
pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})
certOut.Close()
log.Print("written cert.pem\n")
// this will create plain text PEM file.
pemfile, _ := os.Create(path + ".pem")
var pemkey = &pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: x509.MarshalPKCS1PrivateKey(privatekey)}
pem.Encode(pemfile, pemkey)
pemfile.Close()
keyOut, err := os.OpenFile(path+"key.pem", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
log.Print("failed to open key.pem for writing:", err)
return
}
pem.Encode(keyOut, pemBlockForKey(priv))
keyOut.Close()
log.Print("written key.pem\n")
}
// Based on https://golang.org/src/crypto/tls/generate_cert.go
func publicKey(priv interface{}) interface{} {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &k.PublicKey
case *ecdsa.PrivateKey:
return &k.PublicKey
default:
return nil
}
}
// Based on https://golang.org/src/crypto/tls/generate_cert.go
func pemBlockForKey(priv interface{}) *pem.Block {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(k)}
case *ecdsa.PrivateKey:
b, err := x509.MarshalECPrivateKey(k)
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to marshal ECDSA private key: %v", err)
os.Exit(2)
}
return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}
default:
return nil
}
}