Commit message: msg/async/ProtocolV1: resurrect "implement cephx_*require_version options"

This was added in commit 9bcbc2a3621f ("mon,msg: implement
cephx_*_require_version options") and inadvertently dropped in
commit e6f043f7d2dc ("msgr/async: huge refactoring of protocol V1").
As a result, service daemons don't enforce cephx_require_version
and cephx_cluster_require_version options and connections without
CEPH_FEATURE_CEPHX_V2 are allowed through.

(cephx_service_require_version enforcement was brought back a
year later in commit 321548010578 ("mon/MonClient: skip CEPHX_V2
challenge if client doesn't support it"), although the peer gets
TAG_BADAUTHORIZER instead of TAG_FEATURES.)

Resurrect the original behaviour: all cephx_*require_version
options are enforced and the peer gets TAG_FEATURES, signifying
that it is missing a required feature.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit 6f5c4152ca2c6423e665cde2196c6301f76043a2)
CVE: CVE-2020-25660
CWE: CWE-294
Vulnerability description: A flaw was found in the Cephx authentication protocol in versions before 15.2.6 and before 14.2.14, where it does not verify Ceph clients correctly and is then vulnerable to replay attacks in Nautilus. This flaw allows an attacker with access to the Ceph cluster network to authenticate with the Ceph service via a packet sniffer and perform actions allowed by the Ceph service. This issue is a reintroduction of CVE-2018-1128, affecting the msgr2 protocol. The msgr 2 protocol is used for all communication except older clients that do not support the msgr2 protocol. The msgr1 protocol is not affected. The highest threat from this vulnerability is to confidentiality, integrity, and system availability.

Project: ceph
File: ProtocolV1.cc

CtPtr ProtocolV1::handle_connect_message_2() {
  ldout(cct, 20) << __func__ << dendl;

  ldout(cct, 20) << __func__ << " accept got peer connect_seq "
                 << connect_msg.connect_seq << " global_seq "
                 << connect_msg.global_seq << dendl;

  connection->set_peer_type(connect_msg.host_type);
  connection->policy = messenger->get_policy(connect_msg.host_type);

  ldout(cct, 10) << __func__ << " accept of host_type " << connect_msg.host_type
                 << ", policy.lossy=" << connection->policy.lossy
                 << " policy.server=" << connection->policy.server
                 << " policy.standby=" << connection->policy.standby
                 << " policy.resetcheck=" << connection->policy.resetcheck
		 << " features 0x" << std::hex << (uint64_t)connect_msg.features
		 << std::dec
                 << dendl;

  ceph_msg_connect_reply reply;
  bufferlist authorizer_reply;

  // FIPS zeroization audit 20191115: this memset is not security related.
  memset(&reply, 0, sizeof(reply));
  reply.protocol_version =
      messenger->get_proto_version(connection->peer_type, false);

  // mismatch?
  ldout(cct, 10) << __func__ << " accept my proto " << reply.protocol_version
                 << ", their proto " << connect_msg.protocol_version << dendl;

  if (connect_msg.protocol_version != reply.protocol_version) {
    return send_connect_message_reply(CEPH_MSGR_TAG_BADPROTOVER, reply,
                                      authorizer_reply);
  }

  // require signatures for cephx?
  if (connect_msg.authorizer_protocol == CEPH_AUTH_CEPHX) {
    if (connection->peer_type == CEPH_ENTITY_TYPE_OSD ||
        connection->peer_type == CEPH_ENTITY_TYPE_MDS ||
        connection->peer_type == CEPH_ENTITY_TYPE_MGR) {
      if (cct->_conf->cephx_require_signatures ||
          cct->_conf->cephx_cluster_require_signatures) {
        ldout(cct, 10)
            << __func__
            << " using cephx, requiring MSG_AUTH feature bit for cluster"
            << dendl;
        connection->policy.features_required |= CEPH_FEATURE_MSG_AUTH;
      }
    } else {
      if (cct->_conf->cephx_require_signatures ||
          cct->_conf->cephx_service_require_signatures) {
        ldout(cct, 10)
            << __func__
            << " using cephx, requiring MSG_AUTH feature bit for service"
            << dendl;
        connection->policy.features_required |= CEPH_FEATURE_MSG_AUTH;
      }
    }
  }

  uint64_t feat_missing =
      connection->policy.features_required & ~(uint64_t)connect_msg.features;
  if (feat_missing) {
    ldout(cct, 1) << __func__ << " peer missing required features " << std::hex
                  << feat_missing << std::dec << dendl;
    return send_connect_message_reply(CEPH_MSGR_TAG_FEATURES, reply,
                                      authorizer_reply);
  }

  bufferlist auth_bl_copy = authorizer_buf;
  auto am = auth_meta;
  am->auth_method = connect_msg.authorizer_protocol;
  connection->lock.unlock();
  ldout(cct,10) << __func__ << " authorizor_protocol "
		<< connect_msg.authorizer_protocol
		<< " len " << auth_bl_copy.length()
		<< dendl;
  bool more = (bool)auth_meta->authorizer_challenge;
  int r = messenger->auth_server->handle_auth_request(
    connection,
    am.get(),
    more,
    am->auth_method,
    auth_bl_copy,
    &authorizer_reply);
  if (r < 0) {
    connection->lock.lock();
    if (state != ACCEPTING_WAIT_CONNECT_MSG_AUTH) {
      ldout(cct, 1) << __func__ << " state changed" << dendl;
      return _fault();
    }
    ldout(cct, 0) << __func__ << ": got bad authorizer, auth_reply_len="
		  << authorizer_reply.length() << dendl;
    session_security.reset();
    return send_connect_message_reply(CEPH_MSGR_TAG_BADAUTHORIZER, reply,
				      authorizer_reply);
  }
  if (r == 0) {
    connection->lock.lock();
    if (state != ACCEPTING_WAIT_CONNECT_MSG_AUTH) {
      ldout(cct, 1) << __func__ << " state changed" << dendl;
      return _fault();
    }
    ldout(cct, 10) << __func__ << ": challenging authorizer" << dendl;
    ceph_assert(authorizer_reply.length());
    return send_connect_message_reply(CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER,
				      reply, authorizer_reply);
  }

  // We've verified the authorizer for this AsyncConnection, so set up the
  // session security structure.  PLR
  ldout(cct, 10) << __func__ << " accept setting up session_security." << dendl;

  if (connection->policy.server &&
      connection->policy.lossy &&
      !connection->policy.register_lossy_clients) {
    // incoming lossy client, no need to register this connection
    // new session
    ldout(cct, 10) << __func__ << " accept new session" << dendl;
    connection->lock.lock();
    return open(reply, authorizer_reply);
  }

  AsyncConnectionRef existing = messenger->lookup_conn(*connection->peer_addrs);

  connection->inject_delay();

  connection->lock.lock();
  if (state != ACCEPTING_WAIT_CONNECT_MSG_AUTH) {
    ldout(cct, 1) << __func__ << " state changed" << dendl;
    return _fault();
  }

  if (existing == connection) {
    existing = nullptr;
  }
  if (existing && existing->protocol->proto_type != 1) {
    ldout(cct,1) << __func__ << " existing " << existing << " proto "
		 << existing->protocol.get() << " version is "
		 << existing->protocol->proto_type << ", marking down" << dendl;
    existing->mark_down();
    existing = nullptr;
  }

  if (existing) {
    // There is no possible that existing connection will acquire this
    // connection's lock
    existing->lock.lock();  // skip lockdep check (we are locking a second
                            // AsyncConnection here)

    ldout(cct,10) << __func__ << " existing=" << existing << " exproto="
		  << existing->protocol.get() << dendl;
    ProtocolV1 *exproto = dynamic_cast<ProtocolV1 *>(existing->protocol.get());
    ceph_assert(exproto);
    ceph_assert(exproto->proto_type == 1);

    if (exproto->state == CLOSED) {
      ldout(cct, 1) << __func__ << " existing " << existing
		    << " already closed." << dendl;
      existing->lock.unlock();
      existing = nullptr;

      return open(reply, authorizer_reply);
    }

    if (exproto->replacing) {
      ldout(cct, 1) << __func__
                    << " existing racing replace happened while replacing."
                    << " existing_state="
                    << connection->get_state_name(existing->state) << dendl;
      reply.global_seq = exproto->peer_global_seq;
      existing->lock.unlock();
      return send_connect_message_reply(CEPH_MSGR_TAG_RETRY_GLOBAL, reply,
                                        authorizer_reply);
    }

    if (connect_msg.global_seq < exproto->peer_global_seq) {
      ldout(cct, 10) << __func__ << " accept existing " << existing << ".gseq "
                     << exproto->peer_global_seq << " > "
                     << connect_msg.global_seq << ", RETRY_GLOBAL" << dendl;
      reply.global_seq = exproto->peer_global_seq;  // so we can send it below..
      existing->lock.unlock();
      return send_connect_message_reply(CEPH_MSGR_TAG_RETRY_GLOBAL, reply,
                                        authorizer_reply);
    } else {
      ldout(cct, 10) << __func__ << " accept existing " << existing << ".gseq "
                     << exproto->peer_global_seq
                     << " <= " << connect_msg.global_seq << ", looks ok"
                     << dendl;
    }

    if (existing->policy.lossy) {
      ldout(cct, 0)
          << __func__
          << " accept replacing existing (lossy) channel (new one lossy="
          << connection->policy.lossy << ")" << dendl;
      exproto->session_reset();
      return replace(existing, reply, authorizer_reply);
    }

    ldout(cct, 1) << __func__ << " accept connect_seq "
                  << connect_msg.connect_seq
                  << " vs existing csq=" << exproto->connect_seq
                  << " existing_state="
                  << connection->get_state_name(existing->state) << dendl;

    if (connect_msg.connect_seq == 0 && exproto->connect_seq > 0) {
      ldout(cct, 0)
          << __func__
          << " accept peer reset, then tried to connect to us, replacing"
          << dendl;
      // this is a hard reset from peer
      is_reset_from_peer = true;
      if (connection->policy.resetcheck) {
        exproto->session_reset();  // this resets out_queue, msg_ and
                                   // connect_seq #'s
      }
      return replace(existing, reply, authorizer_reply);
    }

    if (connect_msg.connect_seq < exproto->connect_seq) {
      // old attempt, or we sent READY but they didn't get it.
      ldout(cct, 10) << __func__ << " accept existing " << existing << ".cseq "
                     << exproto->connect_seq << " > " << connect_msg.connect_seq
                     << ", RETRY_SESSION" << dendl;
      reply.connect_seq = exproto->connect_seq + 1;
      existing->lock.unlock();
      return send_connect_message_reply(CEPH_MSGR_TAG_RETRY_SESSION, reply,
                                        authorizer_reply);
    }

    if (connect_msg.connect_seq == exproto->connect_seq) {
      // if the existing connection successfully opened, and/or
      // subsequently went to standby, then the peer should bump
      // their connect_seq and retry: this is not a connection race
      // we need to resolve here.
      if (exproto->state == OPENED || exproto->state == STANDBY) {
        ldout(cct, 10) << __func__ << " accept connection race, existing "
                       << existing << ".cseq " << exproto->connect_seq
                       << " == " << connect_msg.connect_seq
                       << ", OPEN|STANDBY, RETRY_SESSION " << dendl;
        // if connect_seq both zero, dont stuck into dead lock. it's ok to
        // replace
        if (connection->policy.resetcheck && exproto->connect_seq == 0) {
          return replace(existing, reply, authorizer_reply);
        }

        reply.connect_seq = exproto->connect_seq + 1;
        existing->lock.unlock();
        return send_connect_message_reply(CEPH_MSGR_TAG_RETRY_SESSION, reply,
                                          authorizer_reply);
      }

      // connection race?
      if (connection->peer_addrs->legacy_addr() < messenger->get_myaddr_legacy() ||
          existing->policy.server) {
        // incoming wins
        ldout(cct, 10) << __func__ << " accept connection race, existing "
                       << existing << ".cseq " << exproto->connect_seq
                       << " == " << connect_msg.connect_seq
                       << ", or we are server, replacing my attempt" << dendl;
        return replace(existing, reply, authorizer_reply);
      } else {
        // our existing outgoing wins
        ldout(messenger->cct, 10)
            << __func__ << " accept connection race, existing " << existing
            << ".cseq " << exproto->connect_seq
            << " == " << connect_msg.connect_seq << ", sending WAIT" << dendl;
        ceph_assert(connection->peer_addrs->legacy_addr() >
                    messenger->get_myaddr_legacy());
        existing->lock.unlock();
	// make sure we follow through with opening the existing
	// connection (if it isn't yet open) since we know the peer
	// has something to send to us.
	existing->send_keepalive();
        return send_connect_message_reply(CEPH_MSGR_TAG_WAIT, reply,
                                          authorizer_reply);
      }
    }

    ceph_assert(connect_msg.connect_seq > exproto->connect_seq);
    ceph_assert(connect_msg.global_seq >= exproto->peer_global_seq);
    if (connection->policy.resetcheck &&  // RESETSESSION only used by servers;
                                          // peers do not reset each other
        exproto->connect_seq == 0) {
      ldout(cct, 0) << __func__ << " accept we reset (peer sent cseq "
                    << connect_msg.connect_seq << ", " << existing
                    << ".cseq = " << exproto->connect_seq
                    << "), sending RESETSESSION " << dendl;
      existing->lock.unlock();
      return send_connect_message_reply(CEPH_MSGR_TAG_RESETSESSION, reply,
                                        authorizer_reply);
    }

    // reconnect
    ldout(cct, 10) << __func__ << " accept peer sent cseq "
                   << connect_msg.connect_seq << " > " << exproto->connect_seq
                   << dendl;
    return replace(existing, reply, authorizer_reply);
  }  // existing
  else if (!replacing && connect_msg.connect_seq > 0) {
    // we reset, and they are opening a new session
    ldout(cct, 0) << __func__ << " accept we reset (peer sent cseq "
                  << connect_msg.connect_seq << "), sending RESETSESSION"
                  << dendl;
    return send_connect_message_reply(CEPH_MSGR_TAG_RESETSESSION, reply,
                                      authorizer_reply);
  } else {
    // new session
    ldout(cct, 10) << __func__ << " accept new session" << dendl;
    existing = nullptr;
    return open(reply, authorizer_reply);
  }
}