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  • openssl/ossl_ts.c

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OpenSSL::Timestamp::Factory

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)

Attributes ↑

default_policy_id ↑

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.

call-seq:

factory.default_policy_id = "string" -> string
factory.default_policy_id            -> string or nil

serial_number ↑

Sets or retrieves the serial number to be used for timestamp creation. Must be present for timestamp creation.

call-seq:

factory.serial_number = number -> number
factory.serial_number          -> number or nil

gen_time ↑

Sets or retrieves the Time value to be used in the Response. Must be present for timestamp creation.

call-seq:

factory.gen_time = Time -> Time
factory.gen_time        -> Time or nil

additional_certs ↑

Sets or retrieves 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.

call-seq:

factory.additional_certs = [cert1, cert2] -> [ cert1, cert2 ]
factory.additional_certs                  -> array or nil

allowed_digests ↑

Sets or retrieves the 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.

call-seq:

factory.allowed_digests = ["sha1", OpenSSL::Digest.new('SHA256').new] -> [ "sha1", OpenSSL::Digest) ]
factory.allowed_digests                                               -> array or nil

Attributes

additional_certs[RW]
allowed_digests[RW]
default_policy_id[RW]
gen_time[RW]
serial_number[RW]

Public Instance Methods

create_timestamp(key, certificate, request) → Response click to toggle source

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:

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

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

 
               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;
    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)) {
        int i;
        VALUE rbmd;
        const EVP_MD *md;

        for (i = 0; i < RARRAY_LEN(allowed_digests); i++) {
            rbmd = rb_ary_entry(allowed_digests, i);
            md = (const EVP_MD *)rb_protect(ossl_evp_get_digestbyname_i, rbmd, &status);
            if (status)
                goto end;
            TS_RESP_CTX_add_md(ctx, md);
        }
    }

    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);

    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;
}