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Diffstat (limited to 'src/lib/x509/x509_ext.cpp')
| -rw-r--r-- | src/lib/x509/x509_ext.cpp | 834 |
1 files changed, 834 insertions, 0 deletions
diff --git a/src/lib/x509/x509_ext.cpp b/src/lib/x509/x509_ext.cpp new file mode 100644 index 000000000..23340f784 --- /dev/null +++ b/src/lib/x509/x509_ext.cpp @@ -0,0 +1,834 @@ +/* +* X.509 Certificate Extensions +* (C) 1999-2010,2012 Jack Lloyd +* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/x509_ext.h> +#include <botan/x509cert.h> +#include <botan/sha160.h> +#include <botan/der_enc.h> +#include <botan/ber_dec.h> +#include <botan/oids.h> +#include <botan/charset.h> +#include <botan/internal/bit_ops.h> +#include <algorithm> +#include <sstream> + +namespace Botan { + +/* +* List of X.509 Certificate Extensions +*/ +Certificate_Extension* Extensions::get_extension(const OID& oid, bool critical) + { +#define X509_EXTENSION(NAME, TYPE) \ + if(OIDS::name_of(oid, NAME)) \ + return new Cert_Extension::TYPE(); + + X509_EXTENSION("X509v3.KeyUsage", Key_Usage); + X509_EXTENSION("X509v3.BasicConstraints", Basic_Constraints); + X509_EXTENSION("X509v3.SubjectKeyIdentifier", Subject_Key_ID); + X509_EXTENSION("X509v3.AuthorityKeyIdentifier", Authority_Key_ID); + X509_EXTENSION("X509v3.ExtendedKeyUsage", Extended_Key_Usage); + X509_EXTENSION("X509v3.IssuerAlternativeName", Issuer_Alternative_Name); + X509_EXTENSION("X509v3.SubjectAlternativeName", Subject_Alternative_Name); + X509_EXTENSION("X509v3.NameConstraints", Name_Constraints); + X509_EXTENSION("X509v3.CertificatePolicies", Certificate_Policies); + X509_EXTENSION("X509v3.CRLDistributionPoints", CRL_Distribution_Points); + X509_EXTENSION("PKIX.AuthorityInformationAccess", Authority_Information_Access); + X509_EXTENSION("X509v3.CRLNumber", CRL_Number); + X509_EXTENSION("X509v3.ReasonCode", CRL_ReasonCode); + + return critical ? new Cert_Extension::Unknown_Critical_Extension(oid) : nullptr; + } + +/* +* Extensions Copy Constructor +*/ +Extensions::Extensions(const Extensions& extensions) : ASN1_Object() + { + *this = extensions; + } + +/* +* Extensions Assignment Operator +*/ +Extensions& Extensions::operator=(const Extensions& other) + { + m_extensions.clear(); + + for(size_t i = 0; i != other.m_extensions.size(); ++i) + m_extensions.push_back( + std::make_pair(std::unique_ptr<Certificate_Extension>(other.m_extensions[i].first->copy()), + other.m_extensions[i].second)); + + m_extensions_raw = other.m_extensions_raw; + m_throw_on_unknown_critical = other.m_throw_on_unknown_critical; + + return (*this); + } + +/* +* Return the OID of this extension +*/ +OID Certificate_Extension::oid_of() const + { + return OIDS::lookup(oid_name()); + } + +/* +* Validate the extension (the default implementation is a NOP) +*/ +void Certificate_Extension::validate(const X509_Certificate&, const X509_Certificate&, + const std::vector<std::shared_ptr<const X509_Certificate>>&, + std::vector<std::set<Certificate_Status_Code>>&, + size_t) + { + } + +void Extensions::add(Certificate_Extension* extn, bool critical) + { + m_extensions.push_back(std::make_pair(std::unique_ptr<Certificate_Extension>(extn), critical)); + m_extensions_raw.emplace(extn->oid_of(), std::make_pair(extn->encode_inner(), critical)); + } + +std::vector<std::pair<std::unique_ptr<Certificate_Extension>, bool>> Extensions::extensions() const + { + std::vector<std::pair<std::unique_ptr<Certificate_Extension>, bool>> exts; + for(auto& ext : m_extensions) + { + exts.push_back(std::make_pair(std::unique_ptr<Certificate_Extension>(ext.first->copy()), ext.second)); + } + return exts; + } + +std::map<OID, std::pair<std::vector<byte>, bool>> Extensions::extensions_raw() const + { + return m_extensions_raw; + } + +/* +* Encode an Extensions list +*/ +void Extensions::encode_into(DER_Encoder& to_object) const + { + for(size_t i = 0; i != m_extensions.size(); ++i) + { + const Certificate_Extension* ext = m_extensions[i].first.get(); + const bool is_critical = m_extensions[i].second; + + const bool should_encode = ext->should_encode(); + + if(should_encode) + { + to_object.start_cons(SEQUENCE) + .encode(ext->oid_of()) + .encode_optional(is_critical, false) + .encode(ext->encode_inner(), OCTET_STRING) + .end_cons(); + } + } + } + +/* +* Decode a list of Extensions +*/ +void Extensions::decode_from(BER_Decoder& from_source) + { + m_extensions.clear(); + m_extensions_raw.clear(); + + BER_Decoder sequence = from_source.start_cons(SEQUENCE); + + while(sequence.more_items()) + { + OID oid; + std::vector<byte> value; + bool critical; + + sequence.start_cons(SEQUENCE) + .decode(oid) + .decode_optional(critical, BOOLEAN, UNIVERSAL, false) + .decode(value, OCTET_STRING) + .verify_end() + .end_cons(); + + m_extensions_raw.emplace(oid, std::make_pair(value, critical)); + + std::unique_ptr<Certificate_Extension> ext(get_extension(oid, critical)); + + if(!ext && critical && m_throw_on_unknown_critical) + throw Decoding_Error("Encountered unknown X.509 extension marked " + "as critical; OID = " + oid.as_string()); + + if(ext) + { + try + { + ext->decode_inner(value); + } + catch(std::exception& e) + { + throw Decoding_Error("Exception while decoding extension " + + oid.as_string() + ": " + e.what()); + } + + m_extensions.push_back(std::make_pair(std::move(ext), critical)); + } + } + + sequence.verify_end(); + } + +/* +* Write the extensions to an info store +*/ +void Extensions::contents_to(Data_Store& subject_info, + Data_Store& issuer_info) const + { + for(size_t i = 0; i != m_extensions.size(); ++i) + { + m_extensions[i].first->contents_to(subject_info, issuer_info); + subject_info.add(m_extensions[i].first->oid_name() + ".is_critical", (m_extensions[i].second ? 1 : 0)); + } + } + + +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<byte> Basic_Constraints::encode_inner() const + { + return DER_Encoder() + .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() + .get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void Basic_Constraints::decode_inner(const std::vector<byte>& 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) + .verify_end() + .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<u32bit>(m_path_limit)); + } + +/* +* Encode the extension +*/ +std::vector<byte> 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<byte> 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<byte>& in) + { + BER_Decoder ber(in); + + BER_Object obj = ber.get_next_object(); + + if(obj.type_tag != BIT_STRING || obj.class_tag != UNIVERSAL) + throw BER_Bad_Tag("Bad tag for usage constraint", + obj.type_tag, obj.class_tag); + + if(obj.value.size() != 2 && obj.value.size() != 3) + throw BER_Decoding_Error("Bad size for BITSTRING in usage constraint"); + + if(obj.value[0] >= 8) + throw BER_Decoding_Error("Invalid unused bits in usage constraint"); + + obj.value[obj.value.size()-1] &= (0xFF << obj.value[0]); + + u16bit usage = 0; + for(size_t i = 1; i != obj.value.size(); ++i) + { + usage = (obj.value[i] << 8*(sizeof(usage)-i)) | usage; + } + + 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<byte> Subject_Key_ID::encode_inner() const + { + return DER_Encoder().encode(m_key_id, OCTET_STRING).get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void Subject_Key_ID::decode_inner(const std::vector<byte>& 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<byte>& pub_key) : m_key_id(unlock(SHA_160().process(pub_key))) + {} + +/* +* Encode the extension +*/ +std::vector<byte> Authority_Key_ID::encode_inner() const + { + return DER_Encoder() + .start_cons(SEQUENCE) + .encode(m_key_id, OCTET_STRING, ASN1_Tag(0), CONTEXT_SPECIFIC) + .end_cons() + .get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void Authority_Key_ID::decode_inner(const std::vector<byte>& 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<byte> Alternative_Name::encode_inner() const + { + return DER_Encoder().encode(m_alt_name).get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void Alternative_Name::decode_inner(const std::vector<byte>& in) + { + BER_Decoder(in).decode(m_alt_name); + } + +/* +* Return a textual representation +*/ +void Alternative_Name::contents_to(Data_Store& subject_info, + Data_Store& issuer_info) const + { + std::multimap<std::string, std::string> contents = + get_alt_name().contents(); + + if(m_oid_name_str == "X509v3.SubjectAlternativeName") + subject_info.add(contents); + else if(m_oid_name_str == "X509v3.IssuerAlternativeName") + issuer_info.add(contents); + else + throw Internal_Error("In Alternative_Name, unknown type " + + m_oid_name_str); + } + +/* +* Alternative_Name Constructor +*/ +Alternative_Name::Alternative_Name(const AlternativeName& alt_name, + const std::string& oid_name_str) : + m_oid_name_str(oid_name_str), + m_alt_name(alt_name) + {} + +/* +* Subject_Alternative_Name Constructor +*/ +Subject_Alternative_Name::Subject_Alternative_Name( + const AlternativeName& name) : + Alternative_Name(name, "X509v3.SubjectAlternativeName") + { + } + +/* +* Issuer_Alternative_Name Constructor +*/ +Issuer_Alternative_Name::Issuer_Alternative_Name(const AlternativeName& name) : + Alternative_Name(name, "X509v3.IssuerAlternativeName") + { + } + +/* +* Encode the extension +*/ +std::vector<byte> Extended_Key_Usage::encode_inner() const + { + return DER_Encoder() + .start_cons(SEQUENCE) + .encode_list(m_oids) + .end_cons() + .get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void Extended_Key_Usage::decode_inner(const std::vector<byte>& 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<byte> Name_Constraints::encode_inner() const + { + throw Not_Implemented("Name_Constraints encoding"); + } + + +/* +* Decode the extension +*/ +void Name_Constraints::decode_inner(const std::vector<byte>& in) + { + std::vector<GeneralSubtree> 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.type_tag == 0 && per.class_tag == 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.type_tag == 1 && per.class_tag == 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<std::shared_ptr<const X509_Certificate>>& cert_path, + std::vector<std::set<Certificate_Status_Code>>& 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 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.is_critical("X509v3.NameConstraints"); + 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.is_critical("X509v3.NameConstraints"); + break; + default: + break; + } + } + + if(failed || !permitted) + { + cert_status.at(j).insert(Certificate_Status_Code::NAME_CONSTRAINT_ERROR); + } + } + } + } + +namespace { + +/* +* A policy specifier +*/ +class Policy_Information : public ASN1_Object + { + public: + Policy_Information() {} + 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<byte> Certificate_Policies::encode_inner() const + { + std::vector<Policy_Information> policies; + + for(size_t i = 0; i != m_oids.size(); ++i) + policies.push_back(Policy_Information(m_oids[i])); + + return DER_Encoder() + .start_cons(SEQUENCE) + .encode_list(policies) + .end_cons() + .get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void Certificate_Policies::decode_inner(const std::vector<byte>& in) + { + std::vector<Policy_Information> 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()); + } + +std::vector<byte> Authority_Information_Access::encode_inner() const + { + ASN1_String url(m_ocsp_responder, IA5_STRING); + + return DER_Encoder() + .start_cons(SEQUENCE) + .start_cons(SEQUENCE) + .encode(OIDS::lookup("PKIX.OCSP")) + .add_object(ASN1_Tag(6), CONTEXT_SPECIFIC, url.iso_8859()) + .end_cons() + .end_cons().get_contents_unlocked(); + } + +void Authority_Information_Access::decode_inner(const std::vector<byte>& 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.type_tag == 6 && name.class_tag == CONTEXT_SPECIFIC) + { + m_ocsp_responder = Charset::transcode(ASN1::to_string(name), + LATIN1_CHARSET, + LOCAL_CHARSET); + } + + } + } + } + +void Authority_Information_Access::contents_to(Data_Store& subject, Data_Store&) const + { + if(!m_ocsp_responder.empty()) + subject.add("OCSP.responder", m_ocsp_responder); + } + +/* +* 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<byte> CRL_Number::encode_inner() const + { + return DER_Encoder().encode(m_crl_number).get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void CRL_Number::decode_inner(const std::vector<byte>& in) + { + BER_Decoder(in).decode(m_crl_number); + } + +/* +* Return a textual representation +*/ +void CRL_Number::contents_to(Data_Store& info, Data_Store&) const + { + info.add("X509v3.CRLNumber", static_cast<u32bit>(m_crl_number)); + } + +/* +* Encode the extension +*/ +std::vector<byte> CRL_ReasonCode::encode_inner() const + { + return DER_Encoder() + .encode(static_cast<size_t>(m_reason), ENUMERATED, UNIVERSAL) + .get_contents_unlocked(); + } + +/* +* Decode the extension +*/ +void CRL_ReasonCode::decode_inner(const std::vector<byte>& in) + { + size_t reason_code = 0; + BER_Decoder(in).decode(reason_code, ENUMERATED, UNIVERSAL); + m_reason = static_cast<CRL_Code>(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<byte> CRL_Distribution_Points::encode_inner() const + { + throw Not_Implemented("CRL_Distribution_Points encoding"); + } + +void CRL_Distribution_Points::decode_inner(const std::vector<byte>& buf) + { + BER_Decoder(buf).decode_list(m_distribution_points).verify_end(); + } + +void CRL_Distribution_Points::contents_to(Data_Store& info, Data_Store&) const + { + for(size_t i = 0; i != m_distribution_points.size(); ++i) + { + auto point = m_distribution_points[i].point().contents(); + + auto uris = point.equal_range("URI"); + + for(auto uri = uris.first; uri != uris.second; ++uri) + info.add("CRL.DistributionPoint", uri->second); + } + } + +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<byte> Unknown_Critical_Extension::encode_inner() const + { + throw Not_Implemented("Unknown_Critical_Extension encoding"); + } + +void Unknown_Critical_Extension::decode_inner(const std::vector<byte>&) + { + } + +void Unknown_Critical_Extension::contents_to(Data_Store&, Data_Store&) const + { + } + +} + +} |