/* * X.509 Certificate Extensions * (C) 1999-2010,2012 Jack Lloyd * (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity * (C) 2017 Fabian Weissberg, Rohde & Schwarz Cybersecurity * * Botan is released under the Simplified BSD License (see license.txt) */ #include #include #include #include #include #include #include #include #include #include #include namespace Botan { /* * Create a Certificate_Extension object of some kind to handle */ std::unique_ptr Extensions::create_extn_obj(const OID& oid, bool critical, const std::vector& body) { const std::string oid_str = oid.as_string(); std::unique_ptr extn; if(oid == Cert_Extension::Subject_Key_ID::static_oid()) { extn.reset(new Cert_Extension::Subject_Key_ID); } else if(oid == Cert_Extension::Key_Usage::static_oid()) { extn.reset(new Cert_Extension::Key_Usage); } else if(oid == Cert_Extension::Subject_Alternative_Name::static_oid()) { extn.reset(new Cert_Extension::Subject_Alternative_Name); } else if(oid == Cert_Extension::Issuer_Alternative_Name::static_oid()) { extn.reset(new Cert_Extension::Issuer_Alternative_Name); } else if(oid == Cert_Extension::Basic_Constraints::static_oid()) { extn.reset(new Cert_Extension::Basic_Constraints); } else if(oid == Cert_Extension::CRL_Number::static_oid()) { extn.reset(new Cert_Extension::CRL_Number); } else if(oid == Cert_Extension::CRL_ReasonCode::static_oid()) { extn.reset(new Cert_Extension::CRL_ReasonCode); } else if(oid == Cert_Extension::Authority_Key_ID::static_oid()) { extn.reset(new Cert_Extension::Authority_Key_ID); } else if(oid == Cert_Extension::Name_Constraints::static_oid()) { extn.reset(new Cert_Extension::Name_Constraints); } else if(oid == Cert_Extension::CRL_Distribution_Points::static_oid()) { extn.reset(new Cert_Extension::CRL_Distribution_Points); } else if(oid == Cert_Extension::CRL_Issuing_Distribution_Point::static_oid()) { extn.reset(new Cert_Extension::CRL_Issuing_Distribution_Point); } else if(oid == Cert_Extension::Certificate_Policies::static_oid()) { extn.reset(new Cert_Extension::Certificate_Policies); } else if(oid == Cert_Extension::Extended_Key_Usage::static_oid()) { extn.reset(new Cert_Extension::Extended_Key_Usage); } else if(oid == Cert_Extension::Authority_Information_Access::static_oid()) { extn.reset(new Cert_Extension::Authority_Information_Access); } else { // some other unknown extension type extn.reset(new Cert_Extension::Unknown_Extension(oid, critical)); } try { extn->decode_inner(body); } catch(Decoding_Error&) { extn.reset(new Cert_Extension::Unknown_Extension(oid, critical)); extn->decode_inner(body); } return extn; } /* * Validate the extension (the default implementation is a NOP) */ void Certificate_Extension::validate(const X509_Certificate&, const X509_Certificate&, const std::vector>&, std::vector>&, size_t) { } /* * Add a new cert */ void Extensions::add(Certificate_Extension* extn, bool critical) { // sanity check: we don't want to have the same extension more than once if(m_extension_info.count(extn->oid_of()) > 0) throw Invalid_Argument(extn->oid_name() + " extension already present in Extensions::add"); const OID oid = extn->oid_of(); Extensions_Info info(critical, extn); m_extension_oids.push_back(oid); m_extension_info.emplace(oid, info); } bool Extensions::add_new(Certificate_Extension* extn, bool critical) { if(m_extension_info.count(extn->oid_of()) > 0) { delete extn; return false; // already exists } const OID oid = extn->oid_of(); Extensions_Info info(critical, extn); m_extension_oids.push_back(oid); m_extension_info.emplace(oid, info); return true; } void Extensions::replace(Certificate_Extension* extn, bool critical) { // Remove it if it existed m_extension_info.erase(extn->oid_of()); const OID oid = extn->oid_of(); Extensions_Info info(critical, extn); m_extension_oids.push_back(oid); m_extension_info.emplace(oid, info); } bool Extensions::extension_set(const OID& oid) const { return (m_extension_info.find(oid) != m_extension_info.end()); } bool Extensions::critical_extension_set(const OID& oid) const { auto i = m_extension_info.find(oid); if(i != m_extension_info.end()) return i->second.is_critical(); return false; } const Certificate_Extension* Extensions::get_extension_object(const OID& oid) const { auto extn = m_extension_info.find(oid); if(extn == m_extension_info.end()) return nullptr; return &extn->second.obj(); } std::unique_ptr Extensions::get(const OID& oid) const { if(const Certificate_Extension* ext = this->get_extension_object(oid)) { return std::unique_ptr(ext->copy()); } return nullptr; } std::vector, bool>> Extensions::extensions() const { std::vector, bool>> exts; for(auto&& ext : m_extension_info) { exts.push_back( std::make_pair( std::unique_ptr(ext.second.obj().copy()), ext.second.is_critical()) ); } return exts; } std::map, bool>> Extensions::extensions_raw() const { std::map, bool>> out; for(auto&& ext : m_extension_info) { out.emplace(ext.first, std::make_pair(ext.second.bits(), ext.second.is_critical())); } return out; } /* * Encode an Extensions list */ void Extensions::encode_into(DER_Encoder& to_object) const { for(auto ext_info : m_extension_info) { const OID& oid = ext_info.first; const bool should_encode = ext_info.second.obj().should_encode(); if(should_encode) { const bool is_critical = ext_info.second.is_critical(); const std::vector& ext_value = ext_info.second.bits(); to_object.start_cons(SEQUENCE) .encode(oid) .encode_optional(is_critical, false) .encode(ext_value, OCTET_STRING) .end_cons(); } } } /* * Decode a list of Extensions */ void Extensions::decode_from(BER_Decoder& from_source) { m_extension_oids.clear(); m_extension_info.clear(); BER_Decoder sequence = from_source.start_cons(SEQUENCE); while(sequence.more_items()) { OID oid; bool critical; std::vector bits; sequence.start_cons(SEQUENCE) .decode(oid) .decode_optional(critical, BOOLEAN, UNIVERSAL, false) .decode(bits, OCTET_STRING) .end_cons(); std::unique_ptr obj = create_extn_obj(oid, critical, bits); Extensions_Info info(critical, bits, obj.release()); m_extension_oids.push_back(oid); m_extension_info.emplace(oid, info); } sequence.verify_end(); } /* * Write the extensions to an info store */ void Extensions::contents_to(Data_Store& subject_info, Data_Store& issuer_info) const { for(auto&& m_extn_info : m_extension_info) { m_extn_info.second.obj().contents_to(subject_info, issuer_info); subject_info.add(m_extn_info.second.obj().oid_name() + ".is_critical", m_extn_info.second.is_critical()); } } namespace Cert_Extension { /* * Checked accessor for the path_limit member */ size_t Basic_Constraints::get_path_limit() const { if(!m_is_ca) throw Invalid_State("Basic_Constraints::get_path_limit: Not a CA"); return m_path_limit; } /* * Encode the extension */ std::vector Basic_Constraints::encode_inner() const { std::vector output; DER_Encoder(output) .start_cons(SEQUENCE) .encode_if(m_is_ca, DER_Encoder() .encode(m_is_ca) .encode_optional(m_path_limit, NO_CERT_PATH_LIMIT) ) .end_cons(); return output; } /* * Decode the extension */ void Basic_Constraints::decode_inner(const std::vector& in) { BER_Decoder(in) .start_cons(SEQUENCE) .decode_optional(m_is_ca, BOOLEAN, UNIVERSAL, false) .decode_optional(m_path_limit, INTEGER, UNIVERSAL, NO_CERT_PATH_LIMIT) .end_cons(); if(m_is_ca == false) m_path_limit = 0; } /* * Return a textual representation */ void Basic_Constraints::contents_to(Data_Store& subject, Data_Store&) const { subject.add("X509v3.BasicConstraints.is_ca", (m_is_ca ? 1 : 0)); subject.add("X509v3.BasicConstraints.path_constraint", static_cast(m_path_limit)); } /* * Encode the extension */ std::vector Key_Usage::encode_inner() const { if(m_constraints == NO_CONSTRAINTS) throw Encoding_Error("Cannot encode zero usage constraints"); const size_t unused_bits = low_bit(m_constraints) - 1; std::vector der; der.push_back(BIT_STRING); der.push_back(2 + ((unused_bits < 8) ? 1 : 0)); der.push_back(unused_bits % 8); der.push_back((m_constraints >> 8) & 0xFF); if(m_constraints & 0xFF) der.push_back(m_constraints & 0xFF); return der; } /* * Decode the extension */ void Key_Usage::decode_inner(const std::vector& in) { BER_Decoder ber(in); BER_Object obj = ber.get_next_object(); obj.assert_is_a(BIT_STRING, UNIVERSAL, "usage constraint"); if(obj.length() != 2 && obj.length() != 3) throw BER_Decoding_Error("Bad size for BITSTRING in usage constraint"); uint16_t usage = 0; const uint8_t* bits = obj.bits(); if(bits[0] >= 8) throw BER_Decoding_Error("Invalid unused bits in usage constraint"); const uint8_t mask = static_cast(0xFF << bits[0]); if(obj.length() == 2) { usage = make_uint16(bits[1] & mask, 0); } else if(obj.length() == 3) { usage = make_uint16(bits[1], bits[2] & mask); } m_constraints = Key_Constraints(usage); } /* * Return a textual representation */ void Key_Usage::contents_to(Data_Store& subject, Data_Store&) const { subject.add("X509v3.KeyUsage", m_constraints); } /* * Encode the extension */ std::vector Subject_Key_ID::encode_inner() const { std::vector output; DER_Encoder(output).encode(m_key_id, OCTET_STRING); return output; } /* * Decode the extension */ void Subject_Key_ID::decode_inner(const std::vector& in) { BER_Decoder(in).decode(m_key_id, OCTET_STRING).verify_end(); } /* * Return a textual representation */ void Subject_Key_ID::contents_to(Data_Store& subject, Data_Store&) const { subject.add("X509v3.SubjectKeyIdentifier", m_key_id); } /* * Subject_Key_ID Constructor */ Subject_Key_ID::Subject_Key_ID(const std::vector& pub_key, const std::string& hash_name) { std::unique_ptr hash(HashFunction::create_or_throw(hash_name)); m_key_id.resize(hash->output_length()); hash->update(pub_key); hash->final(m_key_id.data()); // Truncate longer hashes, 192 bits here seems plenty const size_t max_skid_len = (192 / 8); if(m_key_id.size() > max_skid_len) m_key_id.resize(max_skid_len); } /* * Encode the extension */ std::vector Authority_Key_ID::encode_inner() const { std::vector output; DER_Encoder(output) .start_cons(SEQUENCE) .encode(m_key_id, OCTET_STRING, ASN1_Tag(0), CONTEXT_SPECIFIC) .end_cons(); return output; } /* * Decode the extension */ void Authority_Key_ID::decode_inner(const std::vector& in) { BER_Decoder(in) .start_cons(SEQUENCE) .decode_optional_string(m_key_id, OCTET_STRING, 0); } /* * Return a textual representation */ void Authority_Key_ID::contents_to(Data_Store&, Data_Store& issuer) const { if(m_key_id.size()) issuer.add("X509v3.AuthorityKeyIdentifier", m_key_id); } /* * Encode the extension */ std::vector Subject_Alternative_Name::encode_inner() const { std::vector output; DER_Encoder(output).encode(m_alt_name); return output; } /* * Encode the extension */ std::vector Issuer_Alternative_Name::encode_inner() const { std::vector output; DER_Encoder(output).encode(m_alt_name); return output; } /* * Decode the extension */ void Subject_Alternative_Name::decode_inner(const std::vector& in) { BER_Decoder(in).decode(m_alt_name); } /* * Decode the extension */ void Issuer_Alternative_Name::decode_inner(const std::vector& in) { BER_Decoder(in).decode(m_alt_name); } /* * Return a textual representation */ void Subject_Alternative_Name::contents_to(Data_Store& subject_info, Data_Store&) const { subject_info.add(get_alt_name().contents()); } /* * Return a textual representation */ void Issuer_Alternative_Name::contents_to(Data_Store&, Data_Store& issuer_info) const { issuer_info.add(get_alt_name().contents()); } /* * Encode the extension */ std::vector Extended_Key_Usage::encode_inner() const { std::vector output; DER_Encoder(output) .start_cons(SEQUENCE) .encode_list(m_oids) .end_cons(); return output; } /* * Decode the extension */ void Extended_Key_Usage::decode_inner(const std::vector& in) { BER_Decoder(in).decode_list(m_oids); } /* * Return a textual representation */ void Extended_Key_Usage::contents_to(Data_Store& subject, Data_Store&) const { for(size_t i = 0; i != m_oids.size(); ++i) subject.add("X509v3.ExtendedKeyUsage", m_oids[i].as_string()); } /* * Encode the extension */ std::vector Name_Constraints::encode_inner() const { throw Not_Implemented("Name_Constraints encoding"); } /* * Decode the extension */ void Name_Constraints::decode_inner(const std::vector& in) { std::vector permit, exclude; BER_Decoder ber(in); BER_Decoder ext = ber.start_cons(SEQUENCE); BER_Object per = ext.get_next_object(); ext.push_back(per); if(per.is_a(0, ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))) { ext.decode_list(permit,ASN1_Tag(0),ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC)); if(permit.empty()) throw Encoding_Error("Empty Name Contraint list"); } BER_Object exc = ext.get_next_object(); ext.push_back(exc); if(per.is_a(1, ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))) { ext.decode_list(exclude,ASN1_Tag(1),ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC)); if(exclude.empty()) throw Encoding_Error("Empty Name Contraint list"); } ext.end_cons(); if(permit.empty() && exclude.empty()) throw Encoding_Error("Empty Name Contraint extension"); m_name_constraints = NameConstraints(std::move(permit),std::move(exclude)); } /* * Return a textual representation */ void Name_Constraints::contents_to(Data_Store& subject, Data_Store&) const { std::stringstream ss; for(const GeneralSubtree& gs: m_name_constraints.permitted()) { ss << gs; subject.add("X509v3.NameConstraints.permitted", ss.str()); ss.str(std::string()); } for(const GeneralSubtree& gs: m_name_constraints.excluded()) { ss << gs; subject.add("X509v3.NameConstraints.excluded", ss.str()); ss.str(std::string()); } } void Name_Constraints::validate(const X509_Certificate& subject, const X509_Certificate& issuer, const std::vector>& cert_path, std::vector>& cert_status, size_t pos) { if(!m_name_constraints.permitted().empty() || !m_name_constraints.excluded().empty()) { if(!subject.is_CA_cert() || !subject.is_critical("X509v3.NameConstraints")) cert_status.at(pos).insert(Certificate_Status_Code::NAME_CONSTRAINT_ERROR); const bool issuer_name_constraint_critical = issuer.is_critical("X509v3.NameConstraints"); const bool at_self_signed_root = (pos == cert_path.size() - 1); // Check that all subordinate certs pass the name constraint for(size_t j = 0; j <= pos; ++j) { if(pos == j && at_self_signed_root) continue; bool permitted = m_name_constraints.permitted().empty(); bool failed = false; for(auto c: m_name_constraints.permitted()) { switch(c.base().matches(*cert_path.at(j))) { case GeneralName::MatchResult::NotFound: case GeneralName::MatchResult::All: permitted = true; break; case GeneralName::MatchResult::UnknownType: failed = issuer_name_constraint_critical; permitted = true; break; default: break; } } for(auto c: m_name_constraints.excluded()) { switch(c.base().matches(*cert_path.at(j))) { case GeneralName::MatchResult::All: case GeneralName::MatchResult::Some: failed = true; break; case GeneralName::MatchResult::UnknownType: failed = issuer_name_constraint_critical; break; default: break; } } if(failed || !permitted) { cert_status.at(j).insert(Certificate_Status_Code::NAME_CONSTRAINT_ERROR); } } } } namespace { /* * A policy specifier */ class Policy_Information final : public ASN1_Object { public: Policy_Information() = default; explicit Policy_Information(const OID& oid) : m_oid(oid) {} const OID& oid() const { return m_oid; } void encode_into(DER_Encoder& codec) const override { codec.start_cons(SEQUENCE) .encode(m_oid) .end_cons(); } void decode_from(BER_Decoder& codec) override { codec.start_cons(SEQUENCE) .decode(m_oid) .discard_remaining() .end_cons(); } private: OID m_oid; }; } /* * Encode the extension */ std::vector Certificate_Policies::encode_inner() const { std::vector policies; for(size_t i = 0; i != m_oids.size(); ++i) policies.push_back(Policy_Information(m_oids[i])); std::vector output; DER_Encoder(output) .start_cons(SEQUENCE) .encode_list(policies) .end_cons(); return output; } /* * Decode the extension */ void Certificate_Policies::decode_inner(const std::vector& in) { std::vector policies; BER_Decoder(in).decode_list(policies); m_oids.clear(); for(size_t i = 0; i != policies.size(); ++i) m_oids.push_back(policies[i].oid()); } /* * Return a textual representation */ void Certificate_Policies::contents_to(Data_Store& info, Data_Store&) const { for(size_t i = 0; i != m_oids.size(); ++i) info.add("X509v3.CertificatePolicies", m_oids[i].as_string()); } void Certificate_Policies::validate( const X509_Certificate& /*subject*/, const X509_Certificate& /*issuer*/, const std::vector>& /*cert_path*/, std::vector>& cert_status, size_t pos) { std::set oid_set(m_oids.begin(), m_oids.end()); if(oid_set.size() != m_oids.size()) { cert_status.at(pos).insert(Certificate_Status_Code::DUPLICATE_CERT_POLICY); } } std::vector Authority_Information_Access::encode_inner() const { ASN1_String url(m_ocsp_responder, IA5_STRING); std::vector output; DER_Encoder(output) .start_cons(SEQUENCE) .start_cons(SEQUENCE) .encode(OIDS::lookup("PKIX.OCSP")) .add_object(ASN1_Tag(6), CONTEXT_SPECIFIC, url.value()) .end_cons() .end_cons(); return output; } void Authority_Information_Access::decode_inner(const std::vector& in) { BER_Decoder ber = BER_Decoder(in).start_cons(SEQUENCE); while(ber.more_items()) { OID oid; BER_Decoder info = ber.start_cons(SEQUENCE); info.decode(oid); if(oid == OIDS::lookup("PKIX.OCSP")) { BER_Object name = info.get_next_object(); if(name.is_a(6, CONTEXT_SPECIFIC)) { m_ocsp_responder = ASN1::to_string(name); } } if(oid == OIDS::lookup("PKIX.CertificateAuthorityIssuers")) { BER_Object name = info.get_next_object(); if(name.is_a(6, CONTEXT_SPECIFIC)) { m_ca_issuers.push_back(ASN1::to_string(name)); } } } } void Authority_Information_Access::contents_to(Data_Store& subject, Data_Store&) const { if(!m_ocsp_responder.empty()) subject.add("OCSP.responder", m_ocsp_responder); for(const std::string& ca_issuer : m_ca_issuers) subject.add("PKIX.CertificateAuthorityIssuers", ca_issuer); } /* * Checked accessor for the crl_number member */ size_t CRL_Number::get_crl_number() const { if(!m_has_value) throw Invalid_State("CRL_Number::get_crl_number: Not set"); return m_crl_number; } /* * Copy a CRL_Number extension */ CRL_Number* CRL_Number::copy() const { if(!m_has_value) throw Invalid_State("CRL_Number::copy: Not set"); return new CRL_Number(m_crl_number); } /* * Encode the extension */ std::vector CRL_Number::encode_inner() const { std::vector output; DER_Encoder(output).encode(m_crl_number); return output; } /* * Decode the extension */ void CRL_Number::decode_inner(const std::vector& in) { BER_Decoder(in).decode(m_crl_number); m_has_value = true; } /* * Return a textual representation */ void CRL_Number::contents_to(Data_Store& info, Data_Store&) const { info.add("X509v3.CRLNumber", static_cast(m_crl_number)); } /* * Encode the extension */ std::vector CRL_ReasonCode::encode_inner() const { std::vector output; DER_Encoder(output).encode(static_cast(m_reason), ENUMERATED, UNIVERSAL); return output; } /* * Decode the extension */ void CRL_ReasonCode::decode_inner(const std::vector& in) { size_t reason_code = 0; BER_Decoder(in).decode(reason_code, ENUMERATED, UNIVERSAL); m_reason = static_cast(reason_code); } /* * Return a textual representation */ void CRL_ReasonCode::contents_to(Data_Store& info, Data_Store&) const { info.add("X509v3.CRLReasonCode", m_reason); } std::vector CRL_Distribution_Points::encode_inner() const { throw Not_Implemented("CRL_Distribution_Points encoding"); } void CRL_Distribution_Points::decode_inner(const std::vector& buf) { BER_Decoder(buf) .decode_list(m_distribution_points) .verify_end(); std::stringstream ss; for(size_t i = 0; i != m_distribution_points.size(); ++i) { auto contents = m_distribution_points[i].point().contents(); for(const auto& pair : contents) { ss << pair.first << ": " << pair.second << " "; } } m_crl_distribution_urls.push_back(ss.str()); } void CRL_Distribution_Points::contents_to(Data_Store& subject, Data_Store&) const { for(const std::string& crl_url : m_crl_distribution_urls) subject.add("CRL.DistributionPoint", crl_url); } void CRL_Distribution_Points::Distribution_Point::encode_into(class DER_Encoder&) const { throw Not_Implemented("CRL_Distribution_Points encoding"); } void CRL_Distribution_Points::Distribution_Point::decode_from(class BER_Decoder& ber) { ber.start_cons(SEQUENCE) .start_cons(ASN1_Tag(0), CONTEXT_SPECIFIC) .decode_optional_implicit(m_point, ASN1_Tag(0), ASN1_Tag(CONTEXT_SPECIFIC | CONSTRUCTED), SEQUENCE, CONSTRUCTED) .end_cons().end_cons(); } std::vector CRL_Issuing_Distribution_Point::encode_inner() const { throw Not_Implemented("CRL_Issuing_Distribution_Point encoding"); } void CRL_Issuing_Distribution_Point::decode_inner(const std::vector& buf) { BER_Decoder(buf).decode(m_distribution_point).verify_end(); } void CRL_Issuing_Distribution_Point::contents_to(Data_Store& info, Data_Store&) const { auto contents = m_distribution_point.point().contents(); std::stringstream ss; for(const auto& pair : contents) { ss << pair.first << ": " << pair.second << " "; } info.add("X509v3.CRLIssuingDistributionPoint", ss.str()); } std::vector Unknown_Extension::encode_inner() const { return m_bytes; } void Unknown_Extension::decode_inner(const std::vector& bytes) { // Just treat as an opaque blob at this level m_bytes = bytes; } void Unknown_Extension::contents_to(Data_Store&, Data_Store&) const { // No information store } } }