go-openssl/pem.go

// Copyright (C) 2014 Space Monkey, Inc.

package openssl

// #cgo pkg-config: openssl
// #include <openssl/ssl.h>
// #include <openssl/conf.h>
import "C"

import (
    "encoding/pem"
    "errors"
    "io/ioutil"
    "runtime"
    "unsafe"
)

type PublicKey interface {
    // MarshalPKIXPublicKeyPEM converts the public key to PEM-encoded PKIX
    // format
    MarshalPKIXPublicKeyPEM() (pem_block []byte, err error)

    // MarshalPKIXPublicKeyDER converts the public key to DER-encoded PKIX
    // format
    MarshalPKIXPublicKeyDER() (der_block []byte, err error)

    evpPKey() *C.EVP_PKEY
}

type PrivateKey interface {
    PublicKey

    // MarshalPKCS1PrivateKeyPEM converts the private key to PEM-encoded PKCS1
    // format
    MarshalPKCS1PrivateKeyPEM() (pem_block []byte, err error)

    // MarshalPKCS1PrivateKeyDER converts the private key to DER-encoded PKCS1
    // format
    MarshalPKCS1PrivateKeyDER() (der_block []byte, err error)
}

type pKey struct {
    key *C.EVP_PKEY
}

func (key *pKey) evpPKey() *C.EVP_PKEY { return key.key }

func (key *pKey) MarshalPKCS1PrivateKeyPEM() (pem_block []byte,
    err error) {
    bio := C.BIO_new(C.BIO_s_mem())
    if bio == nil {
        return nil, errors.New("failed to allocate memory BIO")
    }
    defer C.BIO_free(bio)
    if int(C.PEM_write_bio_PrivateKey(bio, key.key, nil, nil, C.int(0), nil,
        nil)) != 1 {
        return nil, errors.New("failed dumping private key")
    }
    return ioutil.ReadAll(asAnyBio(bio))
}

func (key *pKey) MarshalPKCS1PrivateKeyDER() (der_block []byte,
    err error) {
    // TODO: i can't decipher how to get a generic PKCS1 Private Key in DER
    //    format out of the openssl docs, so until someone who knows better
    //    can chastise me for this, we'll do it this way.
    pem_block, err := key.MarshalPKCS1PrivateKeyPEM()
    if err != nil {
        return nil, err
    }
    var p *pem.Block
    p, pem_block = pem.Decode(pem_block)
    if len(pem_block) > 0 || p == nil {
        return nil, errors.New("something went wrong with PEM generation")
    }
    return p.Bytes, nil
}

func (key *pKey) MarshalPKIXPublicKeyPEM() (pem_block []byte,
    err error) {
    bio := C.BIO_new(C.BIO_s_mem())
    if bio == nil {
        return nil, errors.New("failed to allocate memory BIO")
    }
    defer C.BIO_free(bio)
    if int(C.PEM_write_bio_PUBKEY(bio, key.key)) != 1 {
        return nil, errors.New("failed dumping public key")
    }
    return ioutil.ReadAll(asAnyBio(bio))
}

func (key *pKey) MarshalPKIXPublicKeyDER() (der_block []byte,
    err error) {
    // TODO: i can't decipher how to get a generic PKIX Public Key in DER
    //    format out of the openssl docs, so until someone who knows better
    //    can chastise me for this, we'll do it this way.
    pem_block, err := key.MarshalPKIXPublicKeyPEM()
    if err != nil {
        return nil, err
    }
    var p *pem.Block
    p, pem_block = pem.Decode(pem_block)
    if len(pem_block) > 0 || p == nil {
        return nil, errors.New("something went wrong with PEM generation")
    }
    return p.Bytes, nil
}

// LoadPrivateKey loads a private key from a PEM-encoded block.
func LoadPrivateKey(pem_block []byte) (PrivateKey, error) {
    runtime.LockOSThread()
    defer runtime.UnlockOSThread()
    bio := C.BIO_new_mem_buf(unsafe.Pointer(&pem_block[0]),
        C.int(len(pem_block)))
    key := C.PEM_read_bio_PrivateKey(bio, nil, nil, nil)
    C.BIO_free(bio)
    if key == nil {
        return nil, errorFromErrorQueue()
    }
    p := &pKey{key: key}
    runtime.SetFinalizer(p, func(p *pKey) {
        C.EVP_PKEY_free(p.key)
    })
    return p, nil
}

type Certificate struct {
    x *C.X509
}

// LoadCertificate loads an X509 certificate from a PEM-encoded block.
func LoadCertificate(pem_block []byte) (*Certificate, error) {
    runtime.LockOSThread()
    defer runtime.UnlockOSThread()
    bio := C.BIO_new_mem_buf(unsafe.Pointer(&pem_block[0]),
        C.int(len(pem_block)))
    cert := C.PEM_read_bio_X509(bio, nil, nil, nil)
    C.BIO_free(bio)
    if cert == nil {
        return nil, errorFromErrorQueue()
    }
    x := &Certificate{x: cert}
    runtime.SetFinalizer(x, func(x *Certificate) {
        C.X509_free(x.x)
    })
    return x, nil
}

// MarshalPEM converts the X509 certificate to PEM-encoded format
func (c *Certificate) MarshalPEM() (pem_block []byte, err error) {
    bio := C.BIO_new(C.BIO_s_mem())
    if bio == nil {
        return nil, errors.New("failed to allocate memory BIO")
    }
    defer C.BIO_free(bio)
    if int(C.PEM_write_bio_X509(bio, c.x)) != 1 {
        return nil, errors.New("failed dumping certificate")
    }
    return ioutil.ReadAll(asAnyBio(bio))
}

// PublicKey returns the public key embedded in the X509 certificate.
func (c *Certificate) PublicKey() (PublicKey, error) {
    pkey := C.X509_get_pubkey(c.x)
    if pkey == nil {
        return nil, errors.New("no public key found")
    }
    key := &pKey{key: pkey}
    runtime.SetFinalizer(key, func(key *pKey) {
        C.EVP_PKEY_free(key.key)
    })
    return key, nil
}