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/*
* Copyright (c) 2020, Ali Mohammad Pur <mpfard@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "Certificate.h"
#include <AK/Debug.h>
#include <LibCrypto/ASN1/ASN1.h>
#include <LibCrypto/ASN1/DER.h>
#include <LibCrypto/ASN1/PEM.h>
namespace TLS {
constexpr static Array<int, 4>
common_name_oid { 2, 5, 4, 3 },
country_name_oid { 2, 5, 4, 6 },
locality_name_oid { 2, 5, 4, 7 },
organization_name_oid { 2, 5, 4, 10 },
organizational_unit_name_oid { 2, 5, 4, 11 };
constexpr static Array<int, 7>
rsa_encryption_oid { 1, 2, 840, 113549, 1, 1, 1 },
rsa_md5_encryption_oid { 1, 2, 840, 113549, 1, 1, 4 },
rsa_sha1_encryption_oid { 1, 2, 840, 113549, 1, 1, 5 },
rsa_sha256_encryption_oid { 1, 2, 840, 113549, 1, 1, 11 },
rsa_sha512_encryption_oid { 1, 2, 840, 113549, 1, 1, 13 };
constexpr static Array<int, 4>
subject_alternative_name_oid { 2, 5, 29, 17 };
Optional<Certificate> Certificate::parse_asn1(ReadonlyBytes buffer, bool)
{
#define ENTER_SCOPE_WITHOUT_TYPECHECK(scope) \
do { \
if (auto result = decoder.enter(); result.has_value()) { \
dbgln_if(TLS_DEBUG, "Failed to enter object (" scope "): {}", result.value()); \
return {}; \
} \
} while (0)
#define ENTER_SCOPE_OR_FAIL(kind_name, scope) \
do { \
if (auto tag = decoder.peek(); tag.is_error() || tag.value().kind != Crypto::ASN1::Kind::kind_name) { \
if constexpr (TLS_DEBUG) { \
if (tag.is_error()) \
dbgln(scope " data was invalid: {}", tag.error()); \
else \
dbgln(scope " data was not of kind " #kind_name); \
} \
return {}; \
} \
ENTER_SCOPE_WITHOUT_TYPECHECK(scope); \
} while (0)
#define EXIT_SCOPE(scope) \
do { \
if (auto error = decoder.leave(); error.has_value()) { \
dbgln_if(TLS_DEBUG, "Error while exiting scope " scope ": {}", error.value()); \
return {}; \
} \
} while (0)
#define ENSURE_OBJECT_KIND(_kind_name, scope) \
do { \
if (auto tag = decoder.peek(); tag.is_error() || tag.value().kind != Crypto::ASN1::Kind::_kind_name) { \
if constexpr (TLS_DEBUG) { \
if (tag.is_error()) \
dbgln(scope " data was invalid: {}", tag.error()); \
else \
dbgln(scope " data was not of kind " #_kind_name ", it was {}", Crypto::ASN1::kind_name(tag.value().kind)); \
} \
return {}; \
} \
} while (0)
#define READ_OBJECT_OR_FAIL(kind_name, type_name, value_name, scope) \
auto value_name##_result = decoder.read<type_name>(Crypto::ASN1::Class::Universal, Crypto::ASN1::Kind::kind_name); \
if (value_name##_result.is_error()) { \
dbgln_if(TLS_DEBUG, scope " read of kind " #kind_name " failed: {}", value_name##_result.error()); \
return {}; \
} \
auto value_name = value_name##_result.release_value();
#define DROP_OBJECT_OR_FAIL(scope) \
do { \
if (auto error = decoder.drop(); error.has_value()) { \
dbgln_if(TLS_DEBUG, scope " read failed: {}", error.value()); \
} \
} while (0)
Certificate certificate;
Crypto::ASN1::Decoder decoder { buffer };
// Certificate ::= Sequence {
// certificate TBSCertificate,
// signature_algorithm AlgorithmIdentifier,
// signature_value BitString
// }
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate");
// TBSCertificate ::= Sequence {
// version (0) EXPLICIT Version DEFAULT v1,
// serial_number CertificateSerialNumber,
// signature AlgorithmIdentifier,
// issuer Name,
// validity Validity,
// subject Name,
// subject_public_key_info SubjectPublicKeyInfo,
// issuer_unique_id (1) IMPLICIT UniqueIdentifer OPTIONAL (if present, version > v1),
// subject_unique_id (2) IMPLICIT UniqueIdentiier OPTIONAL (if present, version > v1),
// extensions (3) EXPLICIT Extensions OPTIONAL (if present, version > v2)
// }
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate");
// version
{
// Version :: Integer { v1(0), v2(1), v3(2) } (Optional)
if (auto tag = decoder.peek(); !tag.is_error() && tag.value().type == Crypto::ASN1::Type::Constructed) {
ENTER_SCOPE_WITHOUT_TYPECHECK("Certificate::version");
READ_OBJECT_OR_FAIL(Integer, Crypto::UnsignedBigInteger, value, "Certificate::version");
if (!(value < 3)) {
dbgln_if(TLS_DEBUG, "Certificate::version Invalid value for version: {}", value.to_base(10));
return {};
}
certificate.version = value.words()[0];
EXIT_SCOPE("Certificate::version");
} else {
certificate.version = 0;
}
}
// serial_number
{
// CertificateSerialNumber :: Integer
READ_OBJECT_OR_FAIL(Integer, Crypto::UnsignedBigInteger, value, "Certificate::serial_number");
certificate.serial_number = move(value);
}
auto parse_algorithm_identifier = [&](CertificateKeyAlgorithm& field) -> Optional<bool> {
// AlgorithmIdentifier ::= Sequence {
// algorithm ObjectIdentifier,
// parameters ANY OPTIONAL
// }
ENTER_SCOPE_OR_FAIL(Sequence, "AlgorithmIdentifier");
READ_OBJECT_OR_FAIL(ObjectIdentifier, Vector<int>, identifier, "AlgorithmIdentifier::algorithm");
if (identifier == rsa_encryption_oid)
field = CertificateKeyAlgorithm ::RSA_RSA;
else if (identifier == rsa_md5_encryption_oid)
field = CertificateKeyAlgorithm ::RSA_MD5;
else if (identifier == rsa_sha1_encryption_oid)
field = CertificateKeyAlgorithm ::RSA_SHA1;
else if (identifier == rsa_sha256_encryption_oid)
field = CertificateKeyAlgorithm ::RSA_SHA256;
else if (identifier == rsa_sha512_encryption_oid)
field = CertificateKeyAlgorithm ::RSA_SHA512;
else
return {};
EXIT_SCOPE("AlgorithmIdentifier");
return true;
};
// signature
{
if (!parse_algorithm_identifier(certificate.algorithm).has_value())
return {};
}
auto parse_name = [&](auto& name_struct) -> Optional<bool> {
// Name ::= Choice {
// rdn_sequence RDNSequence
// } // NOTE: since this is the only alternative, there's no index
// RDNSequence ::= Sequence OF RelativeDistinguishedName
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::issuer/subject");
// RelativeDistinguishedName ::= Set OF AttributeTypeAndValue
// AttributeTypeAndValue ::= Sequence {
// type AttributeType,
// value AttributeValue
// }
// AttributeType ::= ObjectIdentifier
// AttributeValue ::= Any
while (!decoder.eof()) {
// Parse only the the required fields, and ignore the rest.
ENTER_SCOPE_OR_FAIL(Set, "Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName");
while (!decoder.eof()) {
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue");
ENSURE_OBJECT_KIND(ObjectIdentifier, "Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::type");
if (auto type_identifier_or_error = decoder.read<Vector<int>>(); !type_identifier_or_error.is_error()) {
// Figure out what type of identifier this is
auto& identifier = type_identifier_or_error.value();
if (identifier == common_name_oid) {
READ_OBJECT_OR_FAIL(PrintableString, StringView, name,
"Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::Value");
name_struct.subject = name;
} else if (identifier == country_name_oid) {
READ_OBJECT_OR_FAIL(PrintableString, StringView, name,
"Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::Value");
name_struct.country = name;
} else if (identifier == locality_name_oid) {
READ_OBJECT_OR_FAIL(PrintableString, StringView, name,
"Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::Value");
name_struct.location = name;
} else if (identifier == organization_name_oid) {
READ_OBJECT_OR_FAIL(PrintableString, StringView, name,
"Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::Value");
name_struct.entity = name;
} else if (identifier == organizational_unit_name_oid) {
READ_OBJECT_OR_FAIL(PrintableString, StringView, name,
"Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::Value");
name_struct.unit = name;
}
} else {
dbgln_if(TLS_DEBUG, "Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue::type data was invalid: {}", type_identifier_or_error.error());
return {};
}
EXIT_SCOPE("Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName::$::AttributeTypeAndValue");
}
EXIT_SCOPE("Certificate::TBSCertificate::issuer/subject::$::RelativeDistinguishedName");
}
EXIT_SCOPE("Certificate::TBSCertificate::issuer/subject");
return true;
};
// issuer
{
if (!parse_name(certificate.issuer).has_value())
return {};
}
// validity
{
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::Validity");
auto parse_time = [&](Core::DateTime& datetime) -> Optional<bool> {
// Time ::= Choice {
// utc_time UTCTime,
// general_time GeneralizedTime
// }
auto tag = decoder.peek();
if (tag.is_error()) {
dbgln_if(1, "Certificate::TBSCertificate::Validity::$::Time failed to read tag: {}", tag.error());
return {};
};
if (tag.value().kind == Crypto::ASN1::Kind::UTCTime) {
READ_OBJECT_OR_FAIL(UTCTime, StringView, time, "Certificate::TBSCertificate::Validity::$");
auto result = Crypto::ASN1::parse_utc_time(time);
if (!result.has_value()) {
dbgln_if(1, "Certificate::TBSCertificate::Validity::$::Time Invalid UTC Time: {}", time);
return {};
}
datetime = result.release_value();
return true;
}
if (tag.value().kind == Crypto::ASN1::Kind::GeneralizedTime) {
READ_OBJECT_OR_FAIL(UTCTime, StringView, time, "Certificate::TBSCertificate::Validity::$");
auto result = Crypto::ASN1::parse_generalized_time(time);
if (!result.has_value()) {
dbgln_if(1, "Certificate::TBSCertificate::Validity::$::Time Invalid Generalized Time: {}", time);
return {};
}
datetime = result.release_value();
return true;
}
dbgln_if(1, "Unrecognised Time format {}", Crypto::ASN1::kind_name(tag.value().kind));
return {};
};
if (!parse_time(certificate.not_before).has_value())
return {};
if (!parse_time(certificate.not_after).has_value())
return {};
EXIT_SCOPE("Certificate::TBSCertificate::Validity");
}
// subject
{
if (!parse_name(certificate.subject).has_value())
return {};
}
// subject_public_key_info
{
// SubjectPublicKeyInfo ::= Sequence {
// algorithm AlgorithmIdentifier,
// subject_public_key BitString
// }
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::subject_public_key_info");
if (!parse_algorithm_identifier(certificate.key_algorithm).has_value())
return {};
READ_OBJECT_OR_FAIL(BitString, const BitmapView, value, "Certificate::TBSCertificate::subject_public_key_info::subject_public_key_info");
// Note: Once we support other kinds of keys, make sure to check the kind here!
auto key = Crypto::PK::RSA::parse_rsa_key({ value.data(), value.size_in_bytes() });
if (!key.public_key.length()) {
dbgln_if(TLS_DEBUG, "Certificate::TBSCertificate::subject_public_key_info::subject_public_key_info: Invalid key");
return {};
}
certificate.public_key = move(key.public_key);
EXIT_SCOPE("Certificate::TBSCertificate::subject_public_key_info");
}
auto parse_unique_identifier = [&]() -> Optional<bool> {
if (certificate.version == 0)
return true;
auto tag = decoder.peek();
if (tag.is_error()) {
dbgln_if(TLS_DEBUG, "Certificate::TBSCertificate::*::UniqueIdentifier could not read tag: {}", tag.error());
return {};
}
// The spec says to just ignore these.
if (static_cast<u8>(tag.value().kind) == 1 || static_cast<u8>(tag.value().kind) == 2)
DROP_OBJECT_OR_FAIL("UniqueIdentifier");
return true;
};
// issuer_unique_identifier
{
if (!parse_unique_identifier().has_value())
return {};
}
// subject_unique_identifier
{
if (!parse_unique_identifier().has_value())
return {};
}
// extensions
{
if (certificate.version == 2) {
auto tag = decoder.peek();
if (tag.is_error()) {
dbgln_if(TLS_DEBUG, "Certificate::TBSCertificate::*::UniqueIdentifier could not read tag: {}", tag.error());
return {};
}
if (static_cast<u8>(tag.value().kind) == 3) {
// Extensions ::= Sequence OF Extension
// Extension ::= Sequence {
// extension_id ObjectIdentifier,
// critical Boolean DEFAULT false,
// extension_value OctetString (DER-encoded)
// }
ENTER_SCOPE_WITHOUT_TYPECHECK("Certificate::TBSCertificate::Extensions(IMPLICIT)");
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::Extensions");
while (!decoder.eof()) {
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::Extensions::$::Extension");
READ_OBJECT_OR_FAIL(ObjectIdentifier, Vector<int>, extension_id, "Certificate::TBSCertificate::Extensions::$::Extension::extension_id");
bool is_critical = false;
if (auto tag = decoder.peek(); !tag.is_error() && tag.value().kind == Crypto::ASN1::Kind::Boolean) {
// Read the 'critical' property
READ_OBJECT_OR_FAIL(Boolean, bool, critical, "Certificate::TBSCertificate::Extensions::$::Extension::critical");
is_critical = critical;
}
READ_OBJECT_OR_FAIL(OctetString, StringView, extension_value, "Certificate::TBSCertificate::Extensions::$::Extension::extension_value");
// Figure out what this extension is.
if (extension_id == subject_alternative_name_oid) {
Crypto::ASN1::Decoder decoder { extension_value.bytes() };
// SubjectAlternativeName ::= GeneralNames
// GeneralNames ::= Sequence OF GeneralName
// GeneralName ::= CHOICE {
// other_name (0) OtherName,
// rfc_822_name (1) IA5String,
// dns_name (2) IA5String,
// x400Address (3) ORAddress,
// directory_name (4) Name,
// edi_party_name (5) EDIPartyName,
// uri (6) IA5String,
// ip_address (7) OctetString,
// registered_id (8) ObjectIdentifier,
// }
ENTER_SCOPE_OR_FAIL(Sequence, "Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName");
while (!decoder.eof()) {
auto tag = decoder.peek();
if (tag.is_error()) {
dbgln_if(TLS_DEBUG, "Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$ could not read tag: {}", tag.error());
return {};
}
auto tag_value = static_cast<u8>(tag.value().kind);
switch (tag_value) {
case 0:
// OtherName
// We don't know how to use this.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::OtherName");
break;
case 1:
// RFC 822 name
// We don't know how to use this.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::RFC822Name");
break;
case 2: {
// DNS Name
READ_OBJECT_OR_FAIL(IA5String, StringView, name, "Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::DNSName");
certificate.SAN.append(name);
break;
}
case 3:
// x400Address
// We don't know how to use this.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::X400Adress");
break;
case 4:
// Directory name
// We don't know how to use this.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::DirectoryName");
break;
case 5:
// edi party name
// We don't know how to use this.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::EDIPartyName");
break;
case 6: {
// URI
READ_OBJECT_OR_FAIL(IA5String, StringView, name, "Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::URI");
certificate.SAN.append(name);
break;
}
case 7:
// IP Address
// We can't handle these.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::IPAddress");
break;
case 8:
// Registered ID
// We can't handle these.
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::RegisteredID");
break;
default:
dbgln_if(TLS_DEBUG, "Unknown tag in SAN choice {}", tag_value);
if (is_critical)
return {};
else
DROP_OBJECT_OR_FAIL("Certificate::TBSCertificate::Extensions::$::Extension::extension_value::SubjectAlternativeName::$::???");
}
}
}
EXIT_SCOPE("Certificate::TBSCertificate::Extensions::$::Extension");
}
EXIT_SCOPE("Certificate::TBSCertificate::Extensions");
EXIT_SCOPE("Certificate::TBSCertificate::Extensions(IMPLICIT)");
}
}
}
// Just ignore the rest of the data for now.
EXIT_SCOPE("Certificate::TBSCertificate");
EXIT_SCOPE("Certificate");
dbgln_if(TLS_DEBUG, "Certificate issued for {} by {}", certificate.subject.subject, certificate.issuer.subject);
return certificate;
#undef DROP_OBJECT_OR_FAIL
#undef ENSURE_OBJECT_KIND
#undef ENTER_SCOPE_OR_FAIL
#undef ENTER_SCOPE_WITHOUT_TYPECHECK
#undef EXIT_SCOPE
#undef READ_OBJECT_OR_FAIL
}
}
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