diff options
author | lloyd <[email protected]> | 2014-01-10 03:41:59 +0000 |
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committer | lloyd <[email protected]> | 2014-01-10 03:41:59 +0000 |
commit | 6894dca64c04936d07048c0e8cbf7e25858548c3 (patch) | |
tree | 5d572bfde9fe667dab14e3f04b5285a85d8acd95 /src/lib/cert/x509/ocsp.cpp | |
parent | 9efa3be92442afb3d0b69890a36c7f122df18eda (diff) |
Move lib into src
Diffstat (limited to 'src/lib/cert/x509/ocsp.cpp')
-rw-r--r-- | src/lib/cert/x509/ocsp.cpp | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/src/lib/cert/x509/ocsp.cpp b/src/lib/cert/x509/ocsp.cpp new file mode 100644 index 000000000..a118a9c4e --- /dev/null +++ b/src/lib/cert/x509/ocsp.cpp @@ -0,0 +1,251 @@ +/* +* OCSP +* (C) 2012,2013 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#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> +#include <botan/http_util.h> +#include <memory> + +namespace Botan { + +namespace OCSP { + +namespace { + +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)); + } + } + +void check_signature(const std::vector<byte>& tbs_response, + const AlgorithmIdentifier& sig_algo, + const std::vector<byte>& signature, + const X509_Certificate& cert) + { + std::unique_ptr<Public_Key> pub_key(cert.subject_public_key()); + + const std::vector<std::string> sig_info = + split_on(OIDS::lookup(sig_algo.oid), '/'); + + if(sig_info.size() != 2 || sig_info[0] != pub_key->algo_name()) + throw std::runtime_error("Information in OCSP response does not match cert"); + + 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(tbs_response), signature)) + throw std::runtime_error("Signature on OCSP response does not verify"); + } + +void check_signature(const std::vector<byte>& tbs_response, + const AlgorithmIdentifier& sig_algo, + const std::vector<byte>& signature, + const Certificate_Store& trusted_roots, + const std::vector<X509_Certificate>& certs) + { + if(certs.size() < 1) + throw std::invalid_argument("Short cert chain for check_signature"); + + if(trusted_roots.certificate_known(certs[0])) + return check_signature(tbs_response, sig_algo, signature, certs[0]); + + // Otherwise attempt to chain the signing cert to a trust root + + if(!certs[0].allowed_usage("PKIX.OCSPSigning")) + throw std::runtime_error("OCSP response cert does not allow OCSP signing"); + + auto result = x509_path_validate(certs, Path_Validation_Restrictions(), trusted_roots); + + if(!result.successful_validation()) + throw std::runtime_error("Certificate validation failure: " + result.result_string()); + + if(!trusted_roots.certificate_known(result.trust_root())) // not needed anymore? + throw std::runtime_error("Certificate chain roots in unknown/untrusted CA"); + + const std::vector<X509_Certificate>& cert_path = result.cert_path(); + + check_signature(tbs_response, sig_algo, signature, cert_path[0]); + } + +} + +std::vector<byte> Request::BER_encode() const + { + CertID certid(m_issuer, m_subject); + + 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(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 Certificate_Store& trusted_roots, + 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 std::runtime_error("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); + + std::vector<byte> tbs_bits; + AlgorithmIdentifier sig_algo; + std::vector<byte> signature; + std::vector<X509_Certificate> certs; + + basicresponse.start_cons(SEQUENCE) + .raw_bytes(tbs_bits) + .end_cons() + .decode(sig_algo) + .decode(signature, BIT_STRING); + decode_optional_list(basicresponse, ASN1_Tag(0), certs); + + size_t responsedata_version = 0; + X509_DN name; + std::vector<byte> key_hash; + X509_Time produced_at; + Extensions extensions; + + BER_Decoder(tbs_bits) + .decode_optional(responsedata_version, ASN1_Tag(0), + ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC)) + + .decode_optional(name, ASN1_Tag(1), + ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC)) + + .decode_optional_string(key_hash, ASN1_Tag(2), + ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC)) + + .decode(produced_at) + + .decode_list(m_responses) + + .decode_optional(extensions, ASN1_Tag(1), + ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC)); + + if(certs.empty()) + { + if(auto cert = trusted_roots.find_cert(name, std::vector<byte>())) + certs.push_back(*cert); + else + throw std::runtime_error("Could not find certificate that signed OCSP response"); + } + + check_signature(tbs_bits, sig_algo, signature, trusted_roots, certs); + } + + response_outer.end_cons(); + } + +Certificate_Status_Code Response::status_for(const X509_Certificate& issuer, + const X509_Certificate& subject) const + { + for(const auto& response : m_responses) + { + if(response.certid().is_id_for(issuer, subject)) + { + X509_Time current_time(std::chrono::system_clock::now()); + + if(response.this_update() > current_time) + return Certificate_Status_Code::OCSP_NOT_YET_VALID; + + if(response.next_update().time_is_set() && current_time > response.next_update()) + return Certificate_Status_Code::OCSP_EXPIRED; + + if(response.cert_status() == 1) + return Certificate_Status_Code::CERT_IS_REVOKED; + else 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; + } + +Response online_check(const X509_Certificate& issuer, + const X509_Certificate& subject, + const Certificate_Store* trusted_roots) + { + const std::string responder_url = subject.ocsp_responder(); + + if(responder_url == "") + throw std::runtime_error("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(*trusted_roots, http.body()); + + return response; + } + +} + +} |