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|
/*
* X.509 Certificates
* (C) 1999-2010,2015 Jack Lloyd
* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/x509cert.h>
#include <botan/x509_ext.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/internal/stl_util.h>
#include <botan/parsing.h>
#include <botan/bigint.h>
#include <botan/oids.h>
#include <botan/pem.h>
#include <botan/hash.h>
#include <botan/hex.h>
#include <algorithm>
#include <iterator>
#include <sstream>
namespace Botan {
namespace {
/*
* Lookup each OID in the vector
*/
std::vector<std::string> lookup_oids(const std::vector<std::string>& in)
{
std::vector<std::string> out;
for(auto i = in.begin(); i != in.end(); ++i)
out.push_back(OIDS::lookup(OID(*i)));
return out;
}
}
/*
* X509_Certificate Constructor
*/
X509_Certificate::X509_Certificate(DataSource& in) :
X509_Object(in, "CERTIFICATE/X509 CERTIFICATE"),
m_self_signed(false),
m_v3_extensions(false)
{
do_decode();
}
/*
* X509_Certificate Constructor
*/
X509_Certificate::X509_Certificate(const std::string& in) :
X509_Object(in, "CERTIFICATE/X509 CERTIFICATE"),
m_self_signed(false),
m_v3_extensions(false)
{
do_decode();
}
/*
* X509_Certificate Constructor
*/
X509_Certificate::X509_Certificate(const std::vector<byte>& in) :
X509_Object(in, "CERTIFICATE/X509 CERTIFICATE"),
m_self_signed(false),
m_v3_extensions(false)
{
do_decode();
}
X509_Certificate::X509_Certificate(const X509_Certificate& other) :
X509_Object(other)
{
m_subject = other.m_subject;
m_issuer = other.m_issuer;
m_self_signed = other.m_self_signed;
m_v3_extensions = other.m_v3_extensions;
}
X509_Certificate& X509_Certificate::operator=(const X509_Certificate& other)
{
if(&other == this)
{
return *this;
}
else
{
X509_Object::operator=(other);
m_subject = other.m_subject;
m_issuer = other.m_issuer;
m_self_signed = other.m_self_signed;
m_v3_extensions = other.m_v3_extensions;
}
return *this;
}
/*
* Decode the TBSCertificate data
*/
void X509_Certificate::force_decode()
{
size_t version;
BigInt serial_bn;
AlgorithmIdentifier sig_algo_inner;
X509_DN dn_issuer, dn_subject;
X509_Time start, end;
BER_Decoder tbs_cert(m_tbs_bits);
tbs_cert.decode_optional(version, ASN1_Tag(0),
ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))
.decode(serial_bn)
.decode(sig_algo_inner)
.decode(dn_issuer)
.start_cons(SEQUENCE)
.decode(start)
.decode(end)
.verify_end()
.end_cons()
.decode(dn_subject);
if(version > 2)
throw Decoding_Error("Unknown X.509 cert version " + std::to_string(version));
if(m_sig_algo != sig_algo_inner)
throw Decoding_Error("Algorithm identifier mismatch");
m_self_signed = (dn_subject == dn_issuer);
m_subject.add(dn_subject.contents());
m_issuer.add(dn_issuer.contents());
m_subject.add("X509.Certificate.dn_bits", ASN1::put_in_sequence(dn_subject.get_bits()));
m_issuer.add("X509.Certificate.dn_bits", ASN1::put_in_sequence(dn_issuer.get_bits()));
BER_Object public_key = tbs_cert.get_next_object();
if(public_key.type_tag != SEQUENCE || public_key.class_tag != CONSTRUCTED)
throw BER_Bad_Tag("X509_Certificate: Unexpected tag for public key",
public_key.type_tag, public_key.class_tag);
std::vector<byte> v2_issuer_key_id, v2_subject_key_id;
tbs_cert.decode_optional_string(v2_issuer_key_id, BIT_STRING, 1);
tbs_cert.decode_optional_string(v2_subject_key_id, BIT_STRING, 2);
BER_Object v3_exts_data = tbs_cert.get_next_object();
if(v3_exts_data.type_tag == 3 &&
v3_exts_data.class_tag == ASN1_Tag(CONSTRUCTED | CONTEXT_SPECIFIC))
{
BER_Decoder(v3_exts_data.value).decode(m_v3_extensions).verify_end();
m_v3_extensions.contents_to(m_subject, m_issuer);
}
else if(v3_exts_data.type_tag != NO_OBJECT)
throw BER_Bad_Tag("Unknown tag in X.509 cert",
v3_exts_data.type_tag, v3_exts_data.class_tag);
if(tbs_cert.more_items())
throw Decoding_Error("TBSCertificate has more items that expected");
m_subject.add("X509.Certificate.version", static_cast<u32bit>(version));
m_subject.add("X509.Certificate.serial", BigInt::encode(serial_bn));
m_subject.add("X509.Certificate.start", start.to_string());
m_subject.add("X509.Certificate.end", end.to_string());
m_issuer.add("X509.Certificate.v2.key_id", v2_issuer_key_id);
m_subject.add("X509.Certificate.v2.key_id", v2_subject_key_id);
m_subject.add("X509.Certificate.public_key",
hex_encode(public_key.value));
if(m_self_signed && version == 0)
{
m_subject.add("X509v3.BasicConstraints.is_ca", 1);
m_subject.add("X509v3.BasicConstraints.path_constraint", Cert_Extension::NO_CERT_PATH_LIMIT);
}
if(is_CA_cert() &&
!m_subject.has_value("X509v3.BasicConstraints.path_constraint"))
{
const size_t limit = (x509_version() < 3) ?
Cert_Extension::NO_CERT_PATH_LIMIT : 0;
m_subject.add("X509v3.BasicConstraints.path_constraint", static_cast<u32bit>(limit));
}
}
/*
* Return the X.509 version in use
*/
u32bit X509_Certificate::x509_version() const
{
return (m_subject.get1_u32bit("X509.Certificate.version") + 1);
}
/*
* Return the time this cert becomes valid
*/
std::string X509_Certificate::start_time() const
{
return m_subject.get1("X509.Certificate.start");
}
/*
* Return the time this cert becomes invalid
*/
std::string X509_Certificate::end_time() const
{
return m_subject.get1("X509.Certificate.end");
}
/*
* Return information about the subject
*/
std::vector<std::string>
X509_Certificate::subject_info(const std::string& what) const
{
return m_subject.get(X509_DN::deref_info_field(what));
}
/*
* Return information about the issuer
*/
std::vector<std::string>
X509_Certificate::issuer_info(const std::string& what) const
{
return m_issuer.get(X509_DN::deref_info_field(what));
}
/*
* Return the public key in this certificate
*/
Public_Key* X509_Certificate::subject_public_key() const
{
return X509::load_key(
ASN1::put_in_sequence(this->subject_public_key_bits()));
}
std::vector<byte> X509_Certificate::subject_public_key_bits() const
{
return hex_decode(m_subject.get1("X509.Certificate.public_key"));
}
/*
* Check if the certificate is for a CA
*/
bool X509_Certificate::is_CA_cert() const
{
if(!m_subject.get1_u32bit("X509v3.BasicConstraints.is_ca"))
return false;
return allowed_usage(Key_Constraints(KEY_CERT_SIGN));
}
bool X509_Certificate::allowed_usage(Key_Constraints usage) const
{
if(constraints() == NO_CONSTRAINTS)
return true;
return ((constraints() & usage) == usage);
}
bool X509_Certificate::allowed_extended_usage(const std::string& usage) const
{
const std::vector<std::string> ex = ex_constraints();
if(ex.empty())
return true;
if(std::find(ex.begin(), ex.end(), usage) != ex.end())
return true;
return false;
}
bool X509_Certificate::allowed_usage(Usage_Type usage) const
{
// These follow suggestions in RFC 5280 4.2.1.12
switch(usage)
{
case Usage_Type::UNSPECIFIED:
return true;
case Usage_Type::TLS_SERVER_AUTH:
return (allowed_usage(KEY_AGREEMENT) || allowed_usage(KEY_ENCIPHERMENT) || allowed_usage(DIGITAL_SIGNATURE)) && allowed_extended_usage("PKIX.ServerAuth");
case Usage_Type::TLS_CLIENT_AUTH:
return (allowed_usage(DIGITAL_SIGNATURE) || allowed_usage(KEY_AGREEMENT)) && allowed_extended_usage("PKIX.ClientAuth");
case Usage_Type::OCSP_RESPONDER:
return (allowed_usage(DIGITAL_SIGNATURE) || allowed_usage(NON_REPUDIATION)) && allowed_extended_usage("PKIX.OCSPSigning");
case Usage_Type::CERTIFICATE_AUTHORITY:
return is_CA_cert();
}
return false;
}
bool X509_Certificate::has_constraints(Key_Constraints constraints) const
{
if(this->constraints() == NO_CONSTRAINTS)
{
return false;
}
return ((this->constraints() & constraints) != 0);
}
bool X509_Certificate::has_ex_constraint(const std::string& ex_constraint) const
{
const std::vector<std::string> ex = ex_constraints();
if(ex.empty())
{
return false;
}
if(std::find(ex.begin(), ex.end(), ex_constraint) != ex.end())
{
return true;
}
return false;
}
/*
* Return the path length constraint
*/
u32bit X509_Certificate::path_limit() const
{
return m_subject.get1_u32bit("X509v3.BasicConstraints.path_constraint", 0);
}
/*
* Return if a certificate extension is marked critical
*/
bool X509_Certificate::is_critical(const std::string& ex_name) const
{
return !!m_subject.get1_u32bit(ex_name + ".is_critical",0);
}
/*
* Return the key usage constraints
*/
Key_Constraints X509_Certificate::constraints() const
{
return Key_Constraints(m_subject.get1_u32bit("X509v3.KeyUsage",
NO_CONSTRAINTS));
}
/*
* Return the list of extended key usage OIDs
*/
std::vector<std::string> X509_Certificate::ex_constraints() const
{
return lookup_oids(m_subject.get("X509v3.ExtendedKeyUsage"));
}
/*
* Return the name constraints
*/
NameConstraints X509_Certificate::name_constraints() const
{
std::vector<GeneralSubtree> permit, exclude;
for(const std::string& v: m_subject.get("X509v3.NameConstraints.permitted"))
{
permit.push_back(GeneralSubtree(v));
}
for(const std::string& v: m_subject.get("X509v3.NameConstraints.excluded"))
{
exclude.push_back(GeneralSubtree(v));
}
return NameConstraints(std::move(permit),std::move(exclude));
}
/*
* Return the list of certificate policies
*/
std::vector<std::string> X509_Certificate::policies() const
{
return lookup_oids(m_subject.get("X509v3.CertificatePolicies"));
}
Extensions X509_Certificate::v3_extensions() const
{
return m_v3_extensions;
}
std::string X509_Certificate::ocsp_responder() const
{
return m_subject.get1("OCSP.responder", "");
}
std::string X509_Certificate::crl_distribution_point() const
{
return m_subject.get1("CRL.DistributionPoint", "");
}
/*
* Return the authority key id
*/
std::vector<byte> X509_Certificate::authority_key_id() const
{
return m_issuer.get1_memvec("X509v3.AuthorityKeyIdentifier");
}
/*
* Return the subject key id
*/
std::vector<byte> X509_Certificate::subject_key_id() const
{
return m_subject.get1_memvec("X509v3.SubjectKeyIdentifier");
}
/*
* Return the certificate serial number
*/
std::vector<byte> X509_Certificate::serial_number() const
{
return m_subject.get1_memvec("X509.Certificate.serial");
}
X509_DN X509_Certificate::issuer_dn() const
{
return create_dn(m_issuer);
}
std::vector<byte> X509_Certificate::raw_issuer_dn() const
{
return m_issuer.get1_memvec("X509.Certificate.dn_bits");
}
X509_DN X509_Certificate::subject_dn() const
{
return create_dn(m_subject);
}
std::vector<byte> X509_Certificate::raw_subject_dn() const
{
return m_subject.get1_memvec("X509.Certificate.dn_bits");
}
std::string X509_Certificate::fingerprint(const std::string& hash_name) const
{
std::unique_ptr<HashFunction> hash(HashFunction::create(hash_name));
hash->update(this->BER_encode());
const auto hex_print = hex_encode(hash->final());
std::string formatted_print;
for(size_t i = 0; i != hex_print.size(); i += 2)
{
formatted_print.push_back(hex_print[i]);
formatted_print.push_back(hex_print[i+1]);
if(i != hex_print.size() - 2)
formatted_print.push_back(':');
}
return formatted_print;
}
bool X509_Certificate::matches_dns_name(const std::string& name) const
{
if(name.empty())
return false;
std::vector<std::string> issued_names = subject_info("DNS");
// Fall back to CN only if no DNS names are set (RFC 6125 sec 6.4.4)
if(issued_names.empty())
issued_names = subject_info("Name");
for(size_t i = 0; i != issued_names.size(); ++i)
{
if(host_wildcard_match(issued_names[i], name))
return true;
}
return false;
}
/*
* Compare two certificates for equality
*/
bool X509_Certificate::operator==(const X509_Certificate& other) const
{
return (m_sig == other.m_sig &&
m_sig_algo == other.m_sig_algo &&
m_self_signed == other.m_self_signed &&
m_issuer == other.m_issuer &&
m_subject == other.m_subject);
}
bool X509_Certificate::operator<(const X509_Certificate& other) const
{
/* If signature values are not equal, sort by lexicographic ordering of that */
if(m_sig != other.m_sig)
{
if(m_sig < other.m_sig)
return true;
return false;
}
// Then compare the signed contents
return m_tbs_bits < other.m_tbs_bits;
}
/*
* X.509 Certificate Comparison
*/
bool operator!=(const X509_Certificate& cert1, const X509_Certificate& cert2)
{
return !(cert1 == cert2);
}
std::string X509_Certificate::to_string() const
{
const std::vector<std::string> dn_fields{
"Name",
"Email",
"Organization",
"Organizational Unit",
"Locality",
"State",
"Country",
"IP",
"DNS",
"URI",
"PKIX.XMPPAddr"
};
std::ostringstream out;
for(auto&& field : dn_fields)
{
for(auto&& val : subject_info(field))
{
out << "Subject " << field << ": " << val << "\n";
}
}
for(auto&& field : dn_fields)
{
for(auto&& val : issuer_info(field))
{
out << "Issuer " << field << ": " << val << "\n";
}
}
out << "Version: " << this->x509_version() << "\n";
out << "Not valid before: " << this->start_time() << "\n";
out << "Not valid after: " << this->end_time() << "\n";
out << "Constraints:\n";
Key_Constraints constraints = this->constraints();
if(constraints == NO_CONSTRAINTS)
out << " None\n";
else
{
if(constraints & DIGITAL_SIGNATURE)
out << " Digital Signature\n";
if(constraints & NON_REPUDIATION)
out << " Non-Repudiation\n";
if(constraints & KEY_ENCIPHERMENT)
out << " Key Encipherment\n";
if(constraints & DATA_ENCIPHERMENT)
out << " Data Encipherment\n";
if(constraints & KEY_AGREEMENT)
out << " Key Agreement\n";
if(constraints & KEY_CERT_SIGN)
out << " Cert Sign\n";
if(constraints & CRL_SIGN)
out << " CRL Sign\n";
if(constraints & ENCIPHER_ONLY)
out << " Encipher Only\n";
if(constraints & DECIPHER_ONLY)
out << " Decipher Only\n";
}
std::vector<std::string> policies = this->policies();
if(!policies.empty())
{
out << "Policies: " << "\n";
for(size_t i = 0; i != policies.size(); i++)
out << " " << policies[i] << "\n";
}
std::vector<std::string> ex_constraints = this->ex_constraints();
if(!ex_constraints.empty())
{
out << "Extended Constraints:\n";
for(size_t i = 0; i != ex_constraints.size(); i++)
out << " " << ex_constraints[i] << "\n";
}
NameConstraints name_constraints = this->name_constraints();
if(!name_constraints.permitted().empty() ||
!name_constraints.excluded().empty())
{
out << "Name Constraints:\n";
if(!name_constraints.permitted().empty())
{
out << " Permit";
for(auto st: name_constraints.permitted())
{
out << " " << st.base();
}
out << "\n";
}
if(!name_constraints.excluded().empty())
{
out << " Exclude";
for(auto st: name_constraints.excluded())
{
out << " " << st.base();
}
out << "\n";
}
}
if(!ocsp_responder().empty())
out << "OCSP responder " << ocsp_responder() << "\n";
if(!crl_distribution_point().empty())
out << "CRL " << crl_distribution_point() << "\n";
out << "Signature algorithm: " <<
OIDS::lookup(this->signature_algorithm().oid) << "\n";
out << "Serial number: " << hex_encode(this->serial_number()) << "\n";
if(this->authority_key_id().size())
out << "Authority keyid: " << hex_encode(this->authority_key_id()) << "\n";
if(this->subject_key_id().size())
out << "Subject keyid: " << hex_encode(this->subject_key_id()) << "\n";
std::unique_ptr<X509_PublicKey> pubkey(this->subject_public_key());
out << "Public Key:\n" << X509::PEM_encode(*pubkey);
return out.str();
}
/*
* Create and populate a X509_DN
*/
X509_DN create_dn(const Data_Store& info)
{
auto names = info.search_for(
[](const std::string& key, const std::string&)
{
return (key.find("X520.") != std::string::npos);
});
X509_DN dn;
for(auto i = names.begin(); i != names.end(); ++i)
dn.add_attribute(i->first, i->second);
return dn;
}
/*
* Create and populate an AlternativeName
*/
AlternativeName create_alt_name(const Data_Store& info)
{
auto names = info.search_for(
[](const std::string& key, const std::string&)
{
return (key == "RFC822" ||
key == "DNS" ||
key == "URI" ||
key == "IP");
});
AlternativeName alt_name;
for(auto i = names.begin(); i != names.end(); ++i)
alt_name.add_attribute(i->first, i->second);
return alt_name;
}
}
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