New branch for splitting up path validation vs certificate storage

1 files changed, 660 insertions, 0 deletions

diff --git a/src/cert/x509path/x509path.cpp b/src/cert/x509path/x509path.cpp
new file mode 100644
index 000000000..f3fd091cb
--- /dev/null
+++ b/src/cert/x509path/x509path.cpp
@@ -0,0 +1,660 @@
+/*
+* X.509 Certificate Store
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/x509path.h>
+#include <botan/parsing.h>
+#include <botan/pubkey.h>
+#include <botan/oids.h>
+#include <botan/time.h>
+#include <algorithm>
+#include <memory>
+
+namespace Botan {
+
+namespace {
+
+/*
+* Do a validity check
+*/
+s32bit validity_check(const X509_Time& start, const X509_Time& end,
+                      u64bit current_time, u32bit slack)
+   {
+   const s32bit NOT_YET_VALID = -1, VALID_TIME = 0, EXPIRED = 1;
+
+   if(start.cmp(current_time + slack) > 0)
+      return NOT_YET_VALID;
+   if(end.cmp(current_time - slack) < 0)
+      return EXPIRED;
+   return VALID_TIME;
+   }
+
+/*
+* Compare the value of unique ID fields
+*/
+bool compare_ids(const MemoryVector<byte>& id1,
+                 const MemoryVector<byte>& id2)
+   {
+   if(!id1.size() || !id2.size())
+      return true;
+   return (id1 == id2);
+   }
+
+/*
+* Check a particular usage restriction
+*/
+bool check_usage(const X509_Certificate& cert, X509_Store::Cert_Usage usage,
+                 X509_Store::Cert_Usage check_for, Key_Constraints constraints)
+   {
+   if((usage & check_for) == 0)
+      return true;
+   if(cert.constraints() == NO_CONSTRAINTS)
+      return true;
+   if(cert.constraints() & constraints)
+      return true;
+   return false;
+   }
+
+/*
+* Check a particular usage restriction
+*/
+bool check_usage(const X509_Certificate& cert, X509_Store::Cert_Usage usage,
+                 X509_Store::Cert_Usage check_for,
+                 const std::string& usage_oid)
+   {
+   if((usage & check_for) == 0)
+      return true;
+
+   const std::vector<std::string> constraints = cert.ex_constraints();
+
+   if(constraints.empty())
+      return true;
+
+   return std::binary_search(constraints.begin(), constraints.end(),
+                             usage_oid);
+   }
+
+/*
+* Check the usage restrictions
+*/
+X509_Code usage_check(const X509_Certificate& cert,
+                      X509_Store::Cert_Usage usage)
+   {
+   if(usage == X509_Store::ANY)
+      return VERIFIED;
+
+   if(!check_usage(cert, usage, X509_Store::CRL_SIGNING, CRL_SIGN))
+      return CA_CERT_NOT_FOR_CRL_ISSUER;
+
+   if(!check_usage(cert, usage, X509_Store::TLS_SERVER, "PKIX.ServerAuth"))
+      return INVALID_USAGE;
+   if(!check_usage(cert, usage, X509_Store::TLS_CLIENT, "PKIX.ClientAuth"))
+      return INVALID_USAGE;
+   if(!check_usage(cert, usage, X509_Store::CODE_SIGNING, "PKIX.CodeSigning"))
+      return INVALID_USAGE;
+   if(!check_usage(cert, usage, X509_Store::EMAIL_PROTECTION,
+                   "PKIX.EmailProtection"))
+      return INVALID_USAGE;
+   if(!check_usage(cert, usage, X509_Store::TIME_STAMPING,
+                   "PKIX.TimeStamping"))
+      return INVALID_USAGE;
+
+   return VERIFIED;
+   }
+
+}
+
+/*
+* Define equality for revocation data
+*/
+bool X509_Store::CRL_Data::operator==(const CRL_Data& other) const
+   {
+   if(issuer != other.issuer)
+      return false;
+   if(serial != other.serial)
+      return false;
+   return compare_ids(auth_key_id, other.auth_key_id);
+   }
+
+/*
+* Define inequality for revocation data
+*/
+bool X509_Store::CRL_Data::operator!=(const CRL_Data& other) const
+   {
+   return !((*this) == other);
+   }
+
+/*
+* Define an ordering for revocation data
+*/
+bool X509_Store::CRL_Data::operator<(const X509_Store::CRL_Data& other) const
+   {
+   if(*this == other)
+      return false;
+
+   const MemoryVector<byte>& serial1 = serial;
+   const MemoryVector<byte>& key_id1 = auth_key_id;
+   const MemoryVector<byte>& serial2 = other.serial;
+   const MemoryVector<byte>& key_id2 = other.auth_key_id;
+
+   if(compare_ids(key_id1, key_id2) == false)
+      {
+      if(std::lexicographical_compare(key_id1.begin(), key_id1.end(),
+                                      key_id2.begin(), key_id2.end()))
+         return true;
+
+      if(std::lexicographical_compare(key_id2.begin(), key_id2.end(),
+                                      key_id1.begin(), key_id1.end()))
+         return false;
+      }
+
+   if(compare_ids(serial1, serial2) == false)
+      {
+      if(std::lexicographical_compare(serial1.begin(), serial1.end(),
+                                      serial2.begin(), serial2.end()))
+         return true;
+
+      if(std::lexicographical_compare(serial2.begin(), serial2.end(),
+                                      serial1.begin(), serial1.end()))
+         return false;
+      }
+
+   return (issuer < other.issuer);
+   }
+
+/*
+* X509_Store Constructor
+*/
+X509_Store::X509_Store(u32bit slack, u32bit cache_timeout)
+   {
+   revoked_info_valid = true;
+
+   validation_cache_timeout = cache_timeout;
+   time_slack = slack;
+   }
+
+/*
+* X509_Store Copy Constructor
+*/
+X509_Store::X509_Store(const X509_Store& other)
+   {
+   certs = other.certs;
+   revoked = other.revoked;
+   revoked_info_valid = other.revoked_info_valid;
+   for(size_t j = 0; j != other.stores.size(); ++j)
+      stores[j] = other.stores[j]->clone();
+   time_slack = other.time_slack;
+   }
+
+/*
+* X509_Store Destructor
+*/
+X509_Store::~X509_Store()
+   {
+   for(size_t j = 0; j != stores.size(); ++j)
+      delete stores[j];
+   }
+
+/*
+* Verify a certificate's authenticity
+*/
+X509_Code X509_Store::validate_cert(const X509_Certificate& cert,
+                                    Cert_Usage cert_usage)
+   {
+   recompute_revoked_info();
+
+   std::vector<size_t> indexes;
+   X509_Code chaining_result = construct_cert_chain(cert, indexes);
+   if(chaining_result != VERIFIED)
+      return chaining_result;
+
+   const u64bit current_time = system_time();
+
+   s32bit time_check = validity_check(cert.start_time(), cert.end_time(),
+                                      current_time, time_slack);
+   if(time_check < 0)      return CERT_NOT_YET_VALID;
+   else if(time_check > 0) return CERT_HAS_EXPIRED;
+
+   X509_Code sig_check_result = check_sig(cert, certs[indexes[0]]);
+   if(sig_check_result != VERIFIED)
+      return sig_check_result;
+
+   if(is_revoked(cert))
+      return CERT_IS_REVOKED;
+
+   for(size_t j = 0; j != indexes.size() - 1; ++j)
+      {
+      const X509_Certificate& current_cert = certs[indexes[j]].cert;
+
+      time_check = validity_check(current_cert.start_time(),
+                                  current_cert.end_time(),
+                                  current_time,
+                                  time_slack);
+
+      if(time_check < 0)      return CERT_NOT_YET_VALID;
+      else if(time_check > 0) return CERT_HAS_EXPIRED;
+
+      sig_check_result = check_sig(certs[indexes[j]], certs[indexes[j+1]]);
+      if(sig_check_result != VERIFIED)
+         return sig_check_result;
+      }
+
+   return usage_check(cert, cert_usage);
+   }
+
+/*
+* Find this certificate
+*/
+size_t X509_Store::find_cert(const X509_DN& subject_dn,
+                             const MemoryRegion<byte>& subject_key_id) const
+   {
+   for(size_t j = 0; j != certs.size(); ++j)
+      {
+      const X509_Certificate& this_cert = certs[j].cert;
+      if(compare_ids(this_cert.subject_key_id(), subject_key_id) &&
+         this_cert.subject_dn() == subject_dn)
+         return j;
+      }
+   return NO_CERT_FOUND;
+   }
+
+/*
+* Find the parent of this certificate
+*/
+size_t X509_Store::find_parent_of(const X509_Certificate& cert)
+   {
+   const X509_DN issuer_dn = cert.issuer_dn();
+   const MemoryVector<byte> auth_key_id = cert.authority_key_id();
+
+   size_t index = find_cert(issuer_dn, auth_key_id);
+
+   if(index != NO_CERT_FOUND)
+      return index;
+
+   for(size_t j = 0; j != stores.size(); ++j)
+      {
+      std::vector<X509_Certificate> got =
+         stores[j]->find_cert_by_subject_and_key_id(issuer_dn, auth_key_id);
+
+      for(size_t k = 0; k != got.size(); ++k)
+         add_cert(got[k]);
+      }
+
+   return find_cert(issuer_dn, auth_key_id);
+   }
+
+/*
+* Construct a chain of certificate relationships
+*/
+X509_Code X509_Store::construct_cert_chain(const X509_Certificate& end_cert,
+                                           std::vector<size_t>& indexes,
+                                           bool need_full_chain)
+   {
+   size_t parent = find_parent_of(end_cert);
+
+   while(true)
+      {
+      if(parent == NO_CERT_FOUND)
+         return CERT_ISSUER_NOT_FOUND;
+      indexes.push_back(parent);
+
+      if(certs[parent].is_verified(validation_cache_timeout))
+         if(certs[parent].verify_result() != VERIFIED)
+            return certs[parent].verify_result();
+
+      const X509_Certificate& parent_cert = certs[parent].cert;
+      if(!parent_cert.is_CA_cert())
+         return CA_CERT_NOT_FOR_CERT_ISSUER;
+
+      if(certs[parent].is_trusted())
+         break;
+      if(parent_cert.is_self_signed())
+         return CANNOT_ESTABLISH_TRUST;
+
+      if(parent_cert.path_limit() < indexes.size() - 1)
+         return CERT_CHAIN_TOO_LONG;
+
+      parent = find_parent_of(parent_cert);
+      }
+
+   if(need_full_chain)
+      return VERIFIED;
+
+   while(true)
+      {
+      if(indexes.size() < 2)
+         break;
+
+      const size_t cert = indexes.back();
+
+      if(certs[cert].is_verified(validation_cache_timeout))
+         {
+         if(certs[cert].verify_result() != VERIFIED)
+            throw Internal_Error("X509_Store::construct_cert_chain");
+         indexes.pop_back();
+         }
+      else
+         break;
+      }
+
+   const size_t last_cert = indexes.back();
+   const size_t parent_of_last_cert = find_parent_of(certs[last_cert].cert);
+   if(parent_of_last_cert == NO_CERT_FOUND)
+      return CERT_ISSUER_NOT_FOUND;
+   indexes.push_back(parent_of_last_cert);
+
+   return VERIFIED;
+   }
+
+/*
+* Check the CAs signature on a certificate
+*/
+X509_Code X509_Store::check_sig(const Cert_Info& cert_info,
+                                const Cert_Info& ca_cert_info) const
+   {
+   if(cert_info.is_verified(validation_cache_timeout))
+      return cert_info.verify_result();
+
+   const X509_Certificate& cert    = cert_info.cert;
+   const X509_Certificate& ca_cert = ca_cert_info.cert;
+
+   X509_Code verify_code = check_sig(cert, ca_cert.subject_public_key());
+
+   cert_info.set_result(verify_code);
+
+   return verify_code;
+   }
+
+/*
+* Check a CA's signature
+*/
+X509_Code X509_Store::check_sig(const X509_Object& object, Public_Key* key)
+   {
+   std::auto_ptr<Public_Key> pub_key(key);
+
+   try {
+      std::vector<std::string> sig_info =
+         split_on(OIDS::lookup(object.signature_algorithm().oid), '/');
+
+      if(sig_info.size() != 2 || sig_info[0] != pub_key->algo_name())
+         return SIGNATURE_ERROR;
+
+      std::string padding = sig_info[1];
+      Signature_Format format;
+      if(key->message_parts() >= 2) format = DER_SEQUENCE;
+      else                          format = IEEE_1363;
+
+      PK_Verifier verifier(*pub_key.get(), padding, format);
+
+      bool valid = verifier.verify_message(object.tbs_data(),
+                                           object.signature());
+
+      if(valid)
+         return VERIFIED;
+      else
+         return SIGNATURE_ERROR;
+      }
+   catch(Lookup_Error)   { return CA_CERT_CANNOT_SIGN; }
+   catch(Decoding_Error) { return CERT_FORMAT_ERROR; }
+   catch(Exception)      {}
+
+   return UNKNOWN_X509_ERROR;
+   }
+
+/*
+* Recompute the revocation status of the certs
+*/
+void X509_Store::recompute_revoked_info() const
+   {
+   if(revoked_info_valid)
+      return;
+
+   for(size_t j = 0; j != certs.size(); ++j)
+      {
+      if((certs[j].is_verified(validation_cache_timeout)) &&
+         (certs[j].verify_result() != VERIFIED))
+         continue;
+
+      if(is_revoked(certs[j].cert))
+         certs[j].set_result(CERT_IS_REVOKED);
+      }
+
+   revoked_info_valid = true;
+   }
+
+/*
+* Check if a certificate is revoked
+*/
+bool X509_Store::is_revoked(const X509_Certificate& cert) const
+   {
+   CRL_Data revoked_info;
+   revoked_info.issuer = cert.issuer_dn();
+   revoked_info.serial = cert.serial_number();
+   revoked_info.auth_key_id = cert.authority_key_id();
+
+   if(std::binary_search(revoked.begin(), revoked.end(), revoked_info))
+      return true;
+   return false;
+   }
+
+/*
+* Construct a path back to a root for this cert
+*/
+std::vector<X509_Certificate>
+X509_Store::get_cert_chain(const X509_Certificate& cert)
+   {
+   std::vector<X509_Certificate> result;
+   std::vector<size_t> indexes;
+   X509_Code chaining_result = construct_cert_chain(cert, indexes, true);
+
+   if(chaining_result != VERIFIED)
+      throw Invalid_State("X509_Store::get_cert_chain: Can't construct chain");
+
+   for(size_t j = 0; j != indexes.size(); ++j)
+      result.push_back(certs[indexes[j]].cert);
+   return result;
+   }
+
+/*
+* Add a certificate store to the list of stores
+*/
+void X509_Store::add_new_certstore(Certificate_Store* certstore)
+   {
+   stores.push_back(certstore);
+   }
+
+/*
+* Add a certificate to the store
+*/
+void X509_Store::add_cert(const X509_Certificate& cert, bool trusted)
+   {
+   if(trusted && !cert.is_self_signed())
+      throw Invalid_Argument("X509_Store: Trusted certs must be self-signed");
+
+   if(find_cert(cert.subject_dn(), cert.subject_key_id()) == NO_CERT_FOUND)
+      {
+      revoked_info_valid = false;
+      Cert_Info info(cert, trusted);
+      certs.push_back(info);
+      }
+   else if(trusted)
+      {
+      for(size_t j = 0; j != certs.size(); ++j)
+         {
+         const X509_Certificate& this_cert = certs[j].cert;
+         if(this_cert == cert)
+            certs[j].trusted = trusted;
+         }
+      }
+   }
+
+/*
+* Add one or more certificates to the store
+*/
+void X509_Store::do_add_certs(DataSource& source, bool trusted)
+   {
+   while(!source.end_of_data())
+      {
+      try {
+         X509_Certificate cert(source);
+         add_cert(cert, trusted);
+         }
+      catch(Decoding_Error) {}
+      catch(Invalid_Argument) {}
+      }
+   }
+
+/*
+* Add one or more certificates to the store
+*/
+void X509_Store::add_certs(DataSource& source)
+   {
+   do_add_certs(source, false);
+   }
+
+/*
+* Add one or more certificates to the store
+*/
+void X509_Store::add_trusted_certs(DataSource& source)
+   {
+   do_add_certs(source, true);
+   }
+
+/*
+* Add one or more certificates to the store
+*/
+X509_Code X509_Store::add_crl(const X509_CRL& crl)
+   {
+   s32bit time_check = validity_check(crl.this_update(), crl.next_update(),
+                                      system_time(), time_slack);
+
+   if(time_check < 0)      return CRL_NOT_YET_VALID;
+   else if(time_check > 0) return CRL_HAS_EXPIRED;
+
+   size_t cert_index = NO_CERT_FOUND;
+
+   for(size_t j = 0; j != certs.size(); ++j)
+      {
+      const X509_Certificate& this_cert = certs[j].cert;
+      if(compare_ids(this_cert.subject_key_id(), crl.authority_key_id()))
+         {
+         if(this_cert.subject_dn() == crl.issuer_dn())
+            cert_index = j;
+         }
+      }
+
+   if(cert_index == NO_CERT_FOUND)
+      return CRL_ISSUER_NOT_FOUND;
+
+   const X509_Certificate& ca_cert = certs[cert_index].cert;
+
+   X509_Code verify_result = validate_cert(ca_cert, CRL_SIGNING);
+   if(verify_result != VERIFIED)
+      return verify_result;
+
+   verify_result = check_sig(crl, ca_cert.subject_public_key());
+   if(verify_result != VERIFIED)
+      return verify_result;
+
+   std::vector<CRL_Entry> revoked_certs = crl.get_revoked();
+
+   for(size_t j = 0; j != revoked_certs.size(); ++j)
+      {
+      CRL_Data revoked_info;
+      revoked_info.issuer = crl.issuer_dn();
+      revoked_info.serial = revoked_certs[j].serial_number();
+      revoked_info.auth_key_id = crl.authority_key_id();
+
+      std::vector<CRL_Data>::iterator p =
+         std::find(revoked.begin(), revoked.end(), revoked_info);
+
+      if(revoked_certs[j].reason_code() == REMOVE_FROM_CRL)
+         {
+         if(p == revoked.end()) continue;
+         revoked.erase(p);
+         }
+      else
+         {
+         if(p != revoked.end()) continue;
+         revoked.push_back(revoked_info);
+         }
+      }
+
+   std::sort(revoked.begin(), revoked.end());
+   revoked_info_valid = false;
+
+   return VERIFIED;
+   }
+
+/*
+* PEM encode the set of certificates
+*/
+std::string X509_Store::PEM_encode() const
+   {
+   std::string cert_store;
+   for(size_t j = 0; j != certs.size(); ++j)
+      cert_store += certs[j].cert.PEM_encode();
+   return cert_store;
+   }
+
+/*
+* Create a Cert_Info structure
+*/
+X509_Store::Cert_Info::Cert_Info(const X509_Certificate& c,
+                                 bool t) : cert(c), trusted(t)
+   {
+   checked = false;
+   result = UNKNOWN_X509_ERROR;
+   last_checked = 0;
+   }
+
+/*
+* Return the verification results
+*/
+X509_Code X509_Store::Cert_Info::verify_result() const
+   {
+   if(!checked)
+      throw Invalid_State("Cert_Info::verify_result() called; not checked");
+   return result;
+   }
+
+/*
+* Set the verification results
+*/
+void X509_Store::Cert_Info::set_result(X509_Code code) const
+   {
+   result = code;
+   last_checked = system_time();
+   checked = true;
+   }
+
+/*
+* Check if this certificate can be trusted
+*/
+bool X509_Store::Cert_Info::is_trusted() const
+   {
+   return trusted;
+   }
+
+/*
+* Check if this certificate has been verified
+*/
+bool X509_Store::Cert_Info::is_verified(u32bit timeout) const
+   {
+   if(!checked)
+      return false;
+   if(result != VERIFIED && result != CERT_NOT_YET_VALID)
+      return true;
+
+   const u64bit current_time = system_time();
+
+   if(current_time > last_checked + timeout)
+      checked = false;
+
+   return checked;
+   }
+
+}