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/*
* OCSP
* (C) 2012,2013 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/ocsp.h>
#include <botan/certstor.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/x509_ext.h>
#include <botan/oids.h>
#include <botan/base64.h>
#include <botan/pubkey.h>
#include <botan/x509path.h>
#if defined(BOTAN_HAS_HTTP_UTIL)
#include <botan/http_util.h>
#endif
namespace Botan {
namespace OCSP {
namespace {
// TODO: should this be in a header somewhere?
void decode_optional_list(BER_Decoder& ber,
ASN1_Tag tag,
std::vector<X509_Certificate>& output)
{
BER_Object obj = ber.get_next_object();
if(obj.type_tag != tag || obj.class_tag != (CONTEXT_SPECIFIC | CONSTRUCTED))
{
ber.push_back(obj);
return;
}
BER_Decoder list(obj.value);
while(list.more_items())
{
BER_Object certbits = list.get_next_object();
X509_Certificate cert(unlock(certbits.value));
output.push_back(std::move(cert));
}
}
}
Request::Request(const X509_Certificate& issuer_cert,
const X509_Certificate& subject_cert) :
m_issuer(issuer_cert),
m_subject(subject_cert),
m_certid(m_issuer, m_subject)
{
}
std::vector<byte> Request::BER_encode() const
{
return DER_Encoder().start_cons(SEQUENCE)
.start_cons(SEQUENCE)
.start_explicit(0)
.encode(static_cast<size_t>(0)) // version #
.end_explicit()
.start_cons(SEQUENCE)
.start_cons(SEQUENCE)
.encode(m_certid)
.end_cons()
.end_cons()
.end_cons()
.end_cons().get_contents_unlocked();
}
std::string Request::base64_encode() const
{
return Botan::base64_encode(BER_encode());
}
Response::Response(const std::vector<byte>& response_bits)
{
BER_Decoder response_outer = BER_Decoder(response_bits).start_cons(SEQUENCE);
size_t resp_status = 0;
response_outer.decode(resp_status, ENUMERATED, UNIVERSAL);
if(resp_status != 0)
throw Exception("OCSP response status " + std::to_string(resp_status));
if(response_outer.more_items())
{
BER_Decoder response_bytes =
response_outer.start_cons(ASN1_Tag(0), CONTEXT_SPECIFIC).start_cons(SEQUENCE);
response_bytes.decode_and_check(OID("1.3.6.1.5.5.7.48.1.1"),
"Unknown response type in OCSP response");
BER_Decoder basicresponse =
BER_Decoder(response_bytes.get_next_octet_string()).start_cons(SEQUENCE);
basicresponse.start_cons(SEQUENCE)
.raw_bytes(m_tbs_bits)
.end_cons()
.decode(m_sig_algo)
.decode(m_signature, BIT_STRING);
decode_optional_list(basicresponse, ASN1_Tag(0), m_certs);
size_t responsedata_version = 0;
Extensions extensions;
BER_Decoder(m_tbs_bits)
.decode_optional(responsedata_version, ASN1_Tag(0),
ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))
.decode_optional(m_signer_name, ASN1_Tag(1),
ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))
.decode_optional_string(m_key_hash, OCTET_STRING, 2,
ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))
.decode(m_produced_at)
.decode_list(m_responses)
.decode_optional(extensions, ASN1_Tag(1),
ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC));
}
response_outer.end_cons();
}
Certificate_Status_Code Response::verify_signature(const X509_Certificate& issuer) const
{
try
{
std::unique_ptr<Public_Key> pub_key(issuer.subject_public_key());
const std::vector<std::string> sig_info =
split_on(OIDS::lookup(m_sig_algo.oid), '/');
if(sig_info.size() != 2 || sig_info[0] != pub_key->algo_name())
return Certificate_Status_Code::OCSP_RESPONSE_INVALID;
std::string padding = sig_info[1];
Signature_Format format = (pub_key->message_parts() >= 2) ? DER_SEQUENCE : IEEE_1363;
PK_Verifier verifier(*pub_key, padding, format);
if(verifier.verify_message(ASN1::put_in_sequence(m_tbs_bits), m_signature))
return Certificate_Status_Code::OCSP_SIGNATURE_OK;
else
return Certificate_Status_Code::OCSP_SIGNATURE_ERROR;
}
catch(Exception&)
{
return Certificate_Status_Code::OCSP_SIGNATURE_ERROR;
}
}
Certificate_Status_Code Response::check_signature(const std::vector<Certificate_Store*>& trusted_roots,
const std::vector<std::shared_ptr<const X509_Certificate>>& ee_cert_path) const
{
std::shared_ptr<const X509_Certificate> signing_cert;
for(size_t i = 0; i != trusted_roots.size(); ++i)
{
if(m_signer_name.empty() && m_key_hash.empty())
return Certificate_Status_Code::OCSP_RESPONSE_INVALID;
if(!m_signer_name.empty())
{
signing_cert = trusted_roots[i]->find_cert(m_signer_name, std::vector<byte>());
if(signing_cert)
{
break;
}
}
if(m_key_hash.size() > 0)
{
signing_cert = trusted_roots[i]->find_cert_by_pubkey_sha1(m_key_hash);
if(signing_cert)
{
break;
}
}
}
if(!signing_cert)
{
for(size_t i = 1; i < ee_cert_path.size(); ++i)
{
// Check all CA certificates in the (assumed validated) EE cert path
if(!m_signer_name.empty() && ee_cert_path[i]->subject_dn() == m_signer_name)
{
signing_cert = ee_cert_path[i];
break;
}
if(m_key_hash.size() > 0 && ee_cert_path[i]->subject_public_key_bitstring_sha1() == m_key_hash)
{
signing_cert = ee_cert_path[i];
break;
}
}
}
// TODO: this ignores m_certs
if(!signing_cert)
return Certificate_Status_Code::OCSP_ISSUER_NOT_FOUND;
if(!signing_cert->allowed_extended_usage("PKIX.OCSPSigning"))
return Certificate_Status_Code::OCSP_RESPONSE_MISSING_KEYUSAGE;
return this->verify_signature(*signing_cert);
}
Certificate_Status_Code Response::status_for(const X509_Certificate& issuer,
const X509_Certificate& subject,
std::chrono::system_clock::time_point ref_time) const
{
for(const auto& response : m_responses)
{
if(response.certid().is_id_for(issuer, subject))
{
X509_Time x509_ref_time(ref_time);
if(response.cert_status() == 1)
return Certificate_Status_Code::CERT_IS_REVOKED;
if(response.this_update() > x509_ref_time)
return Certificate_Status_Code::OCSP_NOT_YET_VALID;
if(response.next_update().time_is_set() && x509_ref_time > response.next_update())
return Certificate_Status_Code::OCSP_HAS_EXPIRED;
if(response.cert_status() == 0)
return Certificate_Status_Code::OCSP_RESPONSE_GOOD;
else
return Certificate_Status_Code::OCSP_BAD_STATUS;
}
}
return Certificate_Status_Code::OCSP_CERT_NOT_LISTED;
}
#if defined(BOTAN_HAS_HTTP_UTIL)
Response online_check(const X509_Certificate& issuer,
const X509_Certificate& subject,
Certificate_Store* trusted_roots)
{
const std::string responder_url = subject.ocsp_responder();
if(responder_url.empty())
throw Exception("No OCSP responder specified");
OCSP::Request req(issuer, subject);
auto http = HTTP::POST_sync(responder_url,
"application/ocsp-request",
req.BER_encode());
http.throw_unless_ok();
// Check the MIME type?
OCSP::Response response(http.body());
std::vector<Certificate_Store*> trusted_roots_vec;
trusted_roots_vec.push_back(trusted_roots);
if(trusted_roots)
response.check_signature(trusted_roots_vec);
return response;
}
#endif
}
}
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