Class: OpenSSL::Timestamp::Factory

Relationships & Source Files
Inherits:	Object
Defined in:	ext/openssl/ossl_ts.c

Overview

Used to generate a Response from scratch.

Please bear in mind that the implementation will always apply and prefer the policy object identifier given in the request over the default policy id specified in the Factory. As a consequence, #default_policy_id will only be applied if no Request#policy_id was given. But this also means that one needs to check the policy identifier in the request manually before creating the Response, e.g. to check whether it complies to a specific set of acceptable policies.

There exists also the possibility to add certificates (instances of ::OpenSSL::X509::Certificate) besides the timestamping certificate that will be included in the resulting timestamp token if Request#cert_requested? is true. Ideally, one would also include any intermediate certificates (the root certificate can be left out - in order to trust it any verifying party will have to be in its possession anyway). This simplifies validation of the timestamp since these intermediate certificates are "already there" and need not be passed as external parameters to Response#verify anymore, thus minimizing external resources needed for verification.

===Example: Inclusion of (untrusted) intermediate certificates

Assume we received a timestamp request that has set Request#policy_id to nil and Request#cert_requested? to true. The raw request bytes are stored in a variable called req_raw. We'd still like to integrate the necessary intermediate certificates (in inter1.cer and inter2.cer) to simplify validation of the resulting Response. ts.p12 is a PKCS#12-compatible file including the private key and the timestamping certificate.

req = OpenSSL::Timestamp::Request.new(raw_bytes)
p12 = OpenSSL::PKCS12.new(File.binread('ts.p12'), 'pwd')
inter1 = OpenSSL::X509::Certificate.new(File.binread('inter1.cer'))
inter2 = OpenSSL::X509::Certificate.new(File.binread('inter2.cer'))
fac = OpenSSL::Timestamp::Factory.new
fac.gen_time = Time.now
fac.serial_number = 1
fac.allowed_digests = ["sha256", "sha384", "sha512"]
#needed because the Request contained no policy identifier
fac.default_policy_id = '1.2.3.4.5'
fac.additional_certificates = [ inter1, inter2 ]
timestamp = fac.create_timestamp(p12.key, p12.certificate, req)

Instance Attribute Summary

#additional_certs rw

Additional certificates apart from the timestamp certificate (e.g. intermediate certificates) to be added to the Response.
#allowed_digests rw

The list of digest algorithms that the factory is allowed create timestamps for.
#default_policy_id rw

A String representing the default policy object identifier, or nil.
#gen_time rw

The Time value to be used in the Response.
#serial_number rw

The serial number to be used for timestamp creation.

Instance Method Summary

#create_timestamp(key, certificate, request) ⇒ Response

Creates a Response with the help of an ::OpenSSL::PKey, an ::OpenSSL::X509::Certificate and a Request.

Instance Attribute Details

#additional_certs (rw)

Additional certificates apart from the timestamp certificate (e.g. intermediate certificates) to be added to the Response. Must be an Array of ::OpenSSL::X509::Certificate, or nil.

[ GitHub ]

#allowed_digests (rw)

The list of digest algorithms that the factory is allowed create timestamps for. Known vulnerable or weak algorithms should not be allowed where possible. Must be an Array of String or ::OpenSSL::Digest subclass instances.

[ GitHub ]

#default_policy_id (rw)

A String representing the default policy object identifier, or nil.

Request#policy_id will always be preferred over this if present in the Request, only if Request#policy_id is nil default_policy will be used. If none of both is present, a TimestampError will be raised when trying to create a Response.

[ GitHub ]

#gen_time (rw)

The Time value to be used in the Response. Must be present for timestamp creation.

[ GitHub ]

#serial_number (rw)

The serial number to be used for timestamp creation. Must be present for timestamp creation. Must be an instance of ::OpenSSL::BN or ::Integer.

[ GitHub ]

Instance Method Details

#create_timestamp(key, certificate, request) ⇒ Response

Creates a Response with the help of an ::OpenSSL::PKey, an ::OpenSSL::X509::Certificate and a Request.

Mandatory parameters for timestamp creation that need to be set in the Request:

Mandatory parameters that need to be set in the Factory:

#serial_number
#gen_time
#allowed_digests

In addition one of either Request#policy_id or #default_policy_id must be set.

Raises a TimestampError if creation fails, though successfully created error responses may be returned.

[ GitHub ]

# File 'ext/openssl/ossl_ts.c', line 1164


static VALUE
ossl_tsfac_create_ts(VALUE self, VALUE key, VALUE certificate, VALUE request)
{
    VALUE serial_number, def_policy_id, gen_time, additional_certs,
          allowed_digests, allowed_digests_tmp = Qnil;
    VALUE str;
    STACK_OF(X509) *inter_certs;
    VALUE tsresp, ret = Qnil;
    EVP_PKEY *sign_key;
    X509 *tsa_cert;
    TS_REQ *req;
    TS_RESP *response = NULL;
    TS_RESP_CTX *ctx = NULL;
    BIO *req_bio;
    ASN1_INTEGER *asn1_serial = NULL;
    ASN1_OBJECT *def_policy_id_obj = NULL;
    long lgen_time;
    const char * err_msg = NULL;
    int status = 0;

    tsresp = NewTSResponse(cTimestampResponse);
    tsa_cert = GetX509CertPtr(certificate);
    sign_key = GetPrivPKeyPtr(key);
    GetTSRequest(request, req);

    gen_time = ossl_tsfac_get_gen_time(self);
    if (!rb_obj_is_instance_of(gen_time, rb_cTime)) {
        err_msg = "@gen_time must be a Time.";
        goto end;
    }
    lgen_time = NUM2LONG(rb_funcall(gen_time, rb_intern("to_i"), 0));

    serial_number = ossl_tsfac_get_serial_number(self);
    if (NIL_P(serial_number)) {
        err_msg = "@serial_number must be set.";
        goto end;
    }
    asn1_serial = num_to_asn1integer(serial_number, NULL);

    def_policy_id = ossl_tsfac_get_default_policy_id(self);
    if (NIL_P(def_policy_id) && !TS_REQ_get_policy_id(req)) {
        err_msg = "No policy id in the request and no default policy set";
        goto end;
    }
    if (!NIL_P(def_policy_id) && !TS_REQ_get_policy_id(req)) {
        def_policy_id_obj = (ASN1_OBJECT*)rb_protect(obj_to_asn1obj_i, (VALUE)def_policy_id, &status);
        if (status)
            goto end;
    }

    if (!(ctx = TS_RESP_CTX_new())) {
        err_msg = "Memory allocation failed.";
        goto end;
    }

    TS_RESP_CTX_set_serial_cb(ctx, ossl_tsfac_serial_cb, &asn1_serial);
    if (!TS_RESP_CTX_set_signer_cert(ctx, tsa_cert)) {
        err_msg = "Certificate does not contain the timestamping extension";
        goto end;
    }

    additional_certs = ossl_tsfac_get_additional_certs(self);
    if (rb_obj_is_kind_of(additional_certs, rb_cArray)) {
        inter_certs = ossl_protect_x509_ary2sk(additional_certs, &status);
        if (status)
            goto end;

        /* this dups the sk_X509 and ups each cert's ref count */
        TS_RESP_CTX_set_certs(ctx, inter_certs);
        sk_X509_pop_free(inter_certs, X509_free);
    }

    TS_RESP_CTX_set_signer_key(ctx, sign_key);
    if (!NIL_P(def_policy_id) && !TS_REQ_get_policy_id(req))
        TS_RESP_CTX_set_def_policy(ctx, def_policy_id_obj);
    if (TS_REQ_get_policy_id(req))
        TS_RESP_CTX_set_def_policy(ctx, TS_REQ_get_policy_id(req));
    TS_RESP_CTX_set_time_cb(ctx, ossl_tsfac_time_cb, &lgen_time);

    allowed_digests = ossl_tsfac_get_allowed_digests(self);
    if (rb_obj_is_kind_of(allowed_digests, rb_cArray)) {
        allowed_digests_tmp = rb_ary_new_capa(RARRAY_LEN(allowed_digests));
        for (long i = 0; i < RARRAY_LEN(allowed_digests); i++) {
            VALUE args[] = {
                allowed_digests_tmp,
                rb_ary_entry(allowed_digests, i),
            };
            const EVP_MD *md = (const EVP_MD *)rb_protect(ossl_evp_md_fetch_i,
                                                          (VALUE)args, &status);
            if (status)
                goto end;
            if (!TS_RESP_CTX_add_md(ctx, md))
                goto end;
        }
    }

    str = rb_protect(ossl_to_der, request, &status);
    if (status)
        goto end;

    req_bio = (BIO*)rb_protect(ossl_obj2bio_i, (VALUE)&str, &status);
    if (status)
        goto end;

    response = TS_RESP_create_response(ctx, req_bio);
    BIO_free(req_bio);
    RB_GC_GUARD(allowed_digests_tmp);

    if (!response) {
        err_msg = "Error during response generation";
        goto end;
    }

    /* bad responses aren't exceptional, but openssl still sets error
     * information. */
    ossl_clear_error();

    SetTSResponse(tsresp, response);
    ret = tsresp;

  end:
    ASN1_INTEGER_free(asn1_serial);
    ASN1_OBJECT_free(def_policy_id_obj);
    TS_RESP_CTX_free(ctx);
    if (err_msg)
        rb_exc_raise(ossl_make_error(eTimestampError, rb_str_new_cstr(err_msg)));
    if (status)
        rb_jump_tag(status);
    return ret;
}