ossl_pkey.c
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/*
* $Id: ossl_pkey.c 33317 2011-09-23 05:17:47Z emboss $
* 'OpenSSL for Ruby' project
* Copyright (C) 2001-2002 Michal Rokos <m.rokos@sh.cvut.cz>
* All rights reserved.
*/
/*
* This program is licenced under the same licence as Ruby.
* (See the file 'LICENCE'.)
*/
#include "ossl.h"
/*
* Classes
*/
VALUE mPKey;
VALUE cPKey;
VALUE ePKeyError;
ID id_private_q;
/*
* callback for generating keys
*/
void
ossl_generate_cb(int p, int n, void *arg)
{
VALUE ary;
ary = rb_ary_new2(2);
rb_ary_store(ary, 0, INT2NUM(p));
rb_ary_store(ary, 1, INT2NUM(n));
rb_yield(ary);
}
/*
* Public
*/
VALUE
ossl_pkey_new(EVP_PKEY *pkey)
{
if (!pkey) {
ossl_raise(ePKeyError, "Cannot make new key from NULL.");
}
switch (EVP_PKEY_type(pkey->type)) {
#if !defined(OPENSSL_NO_RSA)
case EVP_PKEY_RSA:
return ossl_rsa_new(pkey);
#endif
#if !defined(OPENSSL_NO_DSA)
case EVP_PKEY_DSA:
return ossl_dsa_new(pkey);
#endif
#if !defined(OPENSSL_NO_DH)
case EVP_PKEY_DH:
return ossl_dh_new(pkey);
#endif
#if !defined(OPENSSL_NO_EC) && (OPENSSL_VERSION_NUMBER >= 0x0090802fL)
case EVP_PKEY_EC:
return ossl_ec_new(pkey);
#endif
default:
ossl_raise(ePKeyError, "unsupported key type");
}
return Qnil; /* not reached */
}
VALUE
ossl_pkey_new_from_file(VALUE filename)
{
FILE *fp;
EVP_PKEY *pkey;
SafeStringValue(filename);
if (!(fp = fopen(RSTRING_PTR(filename), "r"))) {
ossl_raise(ePKeyError, "%s", strerror(errno));
}
pkey = PEM_read_PrivateKey(fp, NULL, ossl_pem_passwd_cb, NULL);
fclose(fp);
if (!pkey) {
ossl_raise(ePKeyError, NULL);
}
return ossl_pkey_new(pkey);
}
/*
* call-seq:
* OpenSSL::PKey.read(string [, pwd ] ) -> PKey
* OpenSSL::PKey.read(file [, pwd ]) -> PKey
*
* === Parameters
* * +string+ is a DER- or PEM-encoded string containing an arbitrary private
* or public key.
* * +file+ is an instance of +File+ containing a DER- or PEM-encoded
* arbitrary private or public key.
* * +pwd+ is an optional password in case +string+ or +file+ is an encrypted
* PEM resource.
*/
static VALUE
ossl_pkey_new_from_data(int argc, VALUE *argv, VALUE self)
{
EVP_PKEY *pkey;
BIO *bio;
VALUE data, pass;
char *passwd = NULL;
rb_scan_args(argc, argv, "11", &data, &pass);
bio = ossl_obj2bio(data);
if (!(pkey = d2i_PrivateKey_bio(bio, NULL))) {
OSSL_BIO_reset(bio);
if (!NIL_P(pass)) {
passwd = StringValuePtr(pass);
}
if (!(pkey = PEM_read_bio_PrivateKey(bio, NULL, ossl_pem_passwd_cb, passwd))) {
OSSL_BIO_reset(bio);
if (!(pkey = d2i_PUBKEY_bio(bio, NULL))) {
OSSL_BIO_reset(bio);
if (!NIL_P(pass)) {
passwd = StringValuePtr(pass);
}
pkey = PEM_read_bio_PUBKEY(bio, NULL, ossl_pem_passwd_cb, passwd);
}
}
}
BIO_free(bio);
if (!pkey)
ossl_raise(rb_eArgError, "Could not parse PKey");
return ossl_pkey_new(pkey);
}
EVP_PKEY *
GetPKeyPtr(VALUE obj)
{
EVP_PKEY *pkey;
SafeGetPKey(obj, pkey);
return pkey;
}
EVP_PKEY *
GetPrivPKeyPtr(VALUE obj)
{
EVP_PKEY *pkey;
if (rb_funcall(obj, id_private_q, 0, NULL) != Qtrue) {
ossl_raise(rb_eArgError, "Private key is needed.");
}
SafeGetPKey(obj, pkey);
return pkey;
}
EVP_PKEY *
DupPKeyPtr(VALUE obj)
{
EVP_PKEY *pkey;
SafeGetPKey(obj, pkey);
CRYPTO_add(&pkey->references, 1, CRYPTO_LOCK_EVP_PKEY);
return pkey;
}
EVP_PKEY *
DupPrivPKeyPtr(VALUE obj)
{
EVP_PKEY *pkey;
if (rb_funcall(obj, id_private_q, 0, NULL) != Qtrue) {
ossl_raise(rb_eArgError, "Private key is needed.");
}
SafeGetPKey(obj, pkey);
CRYPTO_add(&pkey->references, 1, CRYPTO_LOCK_EVP_PKEY);
return pkey;
}
/*
* Private
*/
static VALUE
ossl_pkey_alloc(VALUE klass)
{
EVP_PKEY *pkey;
VALUE obj;
if (!(pkey = EVP_PKEY_new())) {
ossl_raise(ePKeyError, NULL);
}
WrapPKey(klass, obj, pkey);
return obj;
}
/*
* call-seq:
* PKeyClass.new -> self
*
* Because PKey is an abstract class, actually calling this method explicitly
* will raise a +NotImplementedError+.
*/
static VALUE
ossl_pkey_initialize(VALUE self)
{
if (rb_obj_is_instance_of(self, cPKey)) {
ossl_raise(rb_eNotImpError, "OpenSSL::PKey::PKey is an abstract class.");
}
return self;
}
/*
* call-seq:
* pkey.sign(digest, data) -> String
*
* To sign the +String+ +data+, +digest+, an instance of OpenSSL::Digest, must
* be provided. The return value is again a +String+ containing the signature.
* A PKeyError is raised should errors occur.
* Any previous state of the +Digest+ instance is irrelevant to the signature
* outcome, the digest instance is reset to its initial state during the
* operation.
*
* == Example
* data = 'Sign me!'
* digest = OpenSSL::Digest::SHA256.new
* pkey = OpenSSL::PKey::RSA.new(2048)
* signature = pkey.sign(digest, data)
*/
static VALUE
ossl_pkey_sign(VALUE self, VALUE digest, VALUE data)
{
EVP_PKEY *pkey;
EVP_MD_CTX ctx;
unsigned int buf_len;
VALUE str;
if (rb_funcall(self, id_private_q, 0, NULL) != Qtrue) {
ossl_raise(rb_eArgError, "Private key is needed.");
}
GetPKey(self, pkey);
EVP_SignInit(&ctx, GetDigestPtr(digest));
StringValue(data);
EVP_SignUpdate(&ctx, RSTRING_PTR(data), RSTRING_LEN(data));
str = rb_str_new(0, EVP_PKEY_size(pkey)+16);
if (!EVP_SignFinal(&ctx, (unsigned char *)RSTRING_PTR(str), &buf_len, pkey))
ossl_raise(ePKeyError, NULL);
assert((long)buf_len <= RSTRING_LEN(str));
rb_str_set_len(str, buf_len);
return str;
}
/*
* call-seq:
* pkey.verify(digest, signature, data) -> String
*
* To verify the +String+ +signature+, +digest+, an instance of
* OpenSSL::Digest, must be provided to re-compute the message digest of the
* original +data+, also a +String+. The return value is +true+ if the
* signature is valid, +false+ otherwise. A PKeyError is raised should errors
* occur.
* Any previous state of the +Digest+ instance is irrelevant to the validation
* outcome, the digest instance is reset to its initial state during the
* operation.
*
* == Example
* data = 'Sign me!'
* digest = OpenSSL::Digest::SHA256.new
* pkey = OpenSSL::PKey::RSA.new(2048)
* signature = pkey.sign(digest, data)
* pub_key = pkey.public_key
* puts pub_key.verify(digest, signature, data) # => true
*/
static VALUE
ossl_pkey_verify(VALUE self, VALUE digest, VALUE sig, VALUE data)
{
EVP_PKEY *pkey;
EVP_MD_CTX ctx;
GetPKey(self, pkey);
EVP_VerifyInit(&ctx, GetDigestPtr(digest));
StringValue(sig);
StringValue(data);
EVP_VerifyUpdate(&ctx, RSTRING_PTR(data), RSTRING_LEN(data));
switch (EVP_VerifyFinal(&ctx, (unsigned char *)RSTRING_PTR(sig), RSTRING_LENINT(sig), pkey)) {
case 0:
return Qfalse;
case 1:
return Qtrue;
default:
ossl_raise(ePKeyError, NULL);
}
return Qnil; /* dummy */
}
/*
* INIT
*/
void
Init_ossl_pkey()
{
#if 0
mOSSL = rb_define_module("OpenSSL"); /* let rdoc know about mOSSL */
#endif
/* Document-module: OpenSSL::PKey
*
* == Asymmetric Public Key Algorithms
*
* Asymmetric public key algorithms solve the problem of establishing and
* sharing secret keys to en-/decrypt messages. The key in such an
* algorithm consists of two parts: a public key that may be distributed
* to others and a private key that needs to remain secret.
*
* Messages encrypted with a public key can only be encrypted by
* recipients that are in possession of the associated private key.
* Since public key algorithms are considerably slower than symmetric
* key algorithms (cf. OpenSSL::Cipher) they are often used to establish
* a symmetric key shared between two parties that are in possession of
* each other's public key.
*
* Asymmetric algorithms offer a lot of nice features that are used in a
* lot of different areas. A very common application is the creation and
* validation of digital signatures. To sign a document, the signatory
* generally uses a message digest algorithm (cf. OpenSSL::Digest) to
* compute a digest of the document that is then encrypted (i.e. signed)
* using the private key. Anyone in possession of the public key may then
* verify the signature by computing the message digest of the original
* document on their own, decrypting the signature using the signatory's
* public key and comparing the result to the message digest they
* previously computed. The signature is valid if and only if the
* decrypted signature is equal to this message digest.
*
* The PKey module offers support for three popular public/private key
* algorithms:
* * RSA (OpenSSL::PKey::RSA)
* * DSA (OpenSSL::PKey::DSA)
* * Elliptic Curve Cryptography (OpenSSL::PKey::EC)
* Each of these implementations is in fact a sub-class of the abstract
* PKey class which offers the interface for supporting digital signatures
* in the form of PKey#sign and PKey#verify.
*
* == Diffie-Hellman Key Exchange
*
* Finally PKey also features OpenSSL::PKey::DH, an implementation of
* the Diffie-Hellman key exchange protocol based on discrete logarithms
* in finite fields, the same basis that DSA is built on.
* The Diffie-Hellman protocol can be used to exchange (symmetric) keys
* over insecure channels without needing any prior joint knowledge
* between the participating parties. As the security of DH demands
* relatively long "public keys" (i.e. the part that is overtly
* transmitted between participants) DH tends to be quite slow. If
* security or speed is your primary concern, OpenSSL::PKey::EC offers
* another implementation of the Diffie-Hellman protocol.
*
*/
mPKey = rb_define_module_under(mOSSL, "PKey");
/* Document-class: OpenSSL::PKey::PKeyError
*
*Raised when errors occur during PKey#sign or PKey#verify.
*/
ePKeyError = rb_define_class_under(mPKey, "PKeyError", eOSSLError);
/* Document-class: OpenSSL::PKey::PKey
*
* An abstract class that bundles signature creation (PKey#sign) and
* validation (PKey#verify) that is common to all implementations except
* OpenSSL::PKey::DH
* * OpenSSL::PKey::RSA
* * OpenSSL::PKey::DSA
* * OpenSSL::PKey::EC
*/
cPKey = rb_define_class_under(mPKey, "PKey", rb_cObject);
rb_define_module_function(mPKey, "read", ossl_pkey_new_from_data, -1);
rb_define_alloc_func(cPKey, ossl_pkey_alloc);
rb_define_method(cPKey, "initialize", ossl_pkey_initialize, 0);
rb_define_method(cPKey, "sign", ossl_pkey_sign, 2);
rb_define_method(cPKey, "verify", ossl_pkey_verify, 3);
id_private_q = rb_intern("private?");
/*
* INIT rsa, dsa, dh, ec
*/
Init_ossl_rsa();
Init_ossl_dsa();
Init_ossl_dh();
Init_ossl_ec();
}