openssl

openssl

This is golang binding for openssl, use swig generated interface.

support SSL client, SSL server, digest(md5, sha1, sha256) and cipher(AES).

Usage example

SSL/TLS Client example

package main

import (
    "bufio"
    "log"
    "net/http"
    "os"

    "github.com/fangdingjun/openssl"
)

func main() {
    conn, err := openssl.Dial("tcp", "httpbin.org:443", &openssl.Config{
        ServerName:         "httpbin.org",
        InsecureSkipVerify: false,
    })
    if err != nil {
        log.Fatalf("connect failed %s", err)
    }
    defer conn.Close()

    req, _ := http.NewRequest("GET", "https://httpbin.org/get?key1=value1&key2=value2", nil)
    req.Header.Add("x-cusom-header1", "hello")
    req.Header.Add("connection", "close")

    req.Write(os.Stdout)
    req.Write(conn)

    bufio := bufio.NewReader(conn)
    resp, err := http.ReadResponse(bufio, req)
    if err != nil {
        log.Fatalf("read response failed %#v", err)
    }
    resp.Write(os.Stdout)
}

SSL/TLS Server example

package main

import (
    "bufio"
    "fmt"
    "io"
    "log"
    "net"
    "net/http"
    "os"
    "strings"

    "github.com/fangdingjun/openssl"
)

func handleConn(conn net.Conn) {
    defer conn.Close()

    reader := bufio.NewReader(conn)
    req, err := http.ReadRequest(reader)
    if err != nil {
        log.Println(err)
        return
    }

    // dump request to console
    req.Write(os.Stdout)

    // custom a http response
    res := &http.Response{}

    res.Header = make(http.Header)
    res.Header.Add("x-custom-header", "aaa")
    res.Header.Add("server", "openssl_server/1.0")

    responseText := "hello, world\n"

    res.Header.Add("content-type", "text/plain")
    res.Header.Add("content-length", fmt.Sprintf("%d", len(responseText)))

    res.StatusCode = 200
    res.ProtoMajor = 1
    res.ProtoMinor = 1

    body := strings.NewReader(responseText)
    res.Body = io.NopCloser(body)

    res.Write(conn)
}

func main() {
    key, err := openssl.LoadPrivateKey("../certs/server.key")
    if err != nil {
        log.Fatal(err)
    }
    cert, err := openssl.LoadCertificate("../certs/server.cert")
    if err != nil {
        log.Fatal(err)
    }
    ln, err := openssl.Listen("tcp", ":7777", &openssl.Config{
        Certificate: cert,
        PrivateKey:  key,
    })
    if err != nil {
        log.Fatal(err)
    }
    defer ln.Close()

    for {
        conn, err := ln.Accept()
        if err != nil {
            log.Println(err)
            break
        }
        go handleConn(conn)
    }
}

Crypto example

func md5example() {
    h := openssl.NewMD5()
    defer h.Close()

    h.Write([]byte("hello"))
    h.Flush()
    result := make([]byte, 32)
    n, err := h.Read(result)
    if err != nil {
        log.Println(err)
        return
    }
    fmt.Printf("md5 result %x\n", result[:n])
}

func sha256example() {
    h := openssl.NewSha256()
    defer h.Close()

    h.Write([]byte("hello"))
    h.Flush()
    result := make([]byte, 32)
    n, err := h.Read(result)
    if err != nil {
        log.Println(err)
        return
    }
    fmt.Printf("sha256 result %x\n", result[:n])
}

func aesExample() {
    data := []byte("hello")

    // use random key and iv
    key := make([]byte, 16)
    iv := make([]byte, 12)
    rand.Reader.Read(key)
    rand.Reader.Read(iv)

    encCipher := openssl.NewCipherEncrypt(libssl.EVP_aes_128_gcm(), key, iv)
    defer encCipher.Close()

    encCipher.Write(data)
    encCipher.Flush() // no more data to encrypt

    result := make([]byte, 20)
    n, _ := encCipher.Read(result)
    fmt.Printf("aes encrypt result %x\n", result[:n])

    decCipher := openssl.NewCipherDecrypt(libssl.EVP_aes_128_gcm(), key, iv)
    defer decCipher.Close()

    decCipher.Write(result[:n])
    decCipher.Flush() // no more data to decrypt

    result2 := make([]byte, 32)
    n, _ = decCipher.Read(result2)

    fmt.Printf("aes decrypted result: %s\n", result2[:n])
}

WARNING: this code is not full tested, use it at your own risk!