keydb.h

伯克利做的SFTP安全文件传输协议

// keydb.h
// interface to public key database
// copyright SafeTP Development Group, Inc., 2000  Terms of use are as specified in license.txt

#ifndef __KEYDB_H
#define __KEYDB_H

#include "socketd.h"     // IPAddress
#include "typ.h"         // bool

class DataBlock;         // datablok.h


// interface to key policies
class KeyPolicy {
public:
  // ------ logging actions ------
  // 'key' was received from 'addr'
  virtual void keyReceived(IPAddress addr, DataBlock const &key)=0;

  // the key we received from 'addr' matched what was stored
  virtual void keyMatched(IPAddress addr)=0;

  // ------- policy decisions --------
  // what to do when a server key doesn't match what we already have
  enum MismatchAction {
    MA_ALLOW_ONCE,         // use it, don't store it
    MA_REJECT,             // don't use it
    MA_REPLACE_THIS,       // use it, replace stored key for this addr
    MA_REPLACE_ALL,        // use it, replace all stored keys that match
    NUM_MISMATCH_ACTIONS
  };
  virtual MismatchAction getMismatchAction(
    IPAddress addr, DataBlock const &sentKey, DataBlock const &storedKey,
    int storedKeyCopies, IPAddress const *copyAddrs)=0;

  // what to do when we encounter a never-before seen server
  enum NewServerAction {
    NSA_ACCEPT_ONCE,       // use it, don't store it
    NSA_ACCEPT,            // use it, store it
    NSA_REJECT,            // don't use it
    NUM_NEW_SERVER_ACTIONS
  };
  virtual NewServerAction getNewServerAction(
    IPAddress addr, DataBlock const &sentKey)=0;

  // what to do if a server's reported IP address differs from the
  // address we think we connected to (if it is desired to terminate
  // the connection, throw xsecurity)
  virtual void serverIPMismatch(IPAddress ipServerReported,
                                IPAddress ipConnectedTo,
                                DataBlock const &serverKeySent)=0;
};


// interface to key database:
// a dictionary mapping IP addresses to keys
class KeyDB {
public:
  // returns true if we have a key for the given addr
  virtual bool containsKey(IPAddress addr)=0;

  // returns the key for that addr; containsKey is a precondition
  virtual DataBlock getKey(IPAddress addr)=0;

  // set the key for an addr
  virtual void setKey(IPAddress addr, DataBlock const &key)=0;

  // get all addresses that have keys matching the given key; caller
  // must deallocate the returned array
  virtual IPAddress *getMatchingAddrs(int &numMatching, DataBlock const &key)=0;
};


// collect a policy and a database
struct KeyEnvironment {
public:
  KeyPolicy &policy;
  KeyDB &db;

public:
  KeyEnvironment(KeyPolicy &p, KeyDB &d)
    : policy(p), db(d) {}
};


// called when the server sends a public key
void handleServerKey(DataBlock const &brandedPublicKey, IPAddress hostAddress,
                     KeyEnvironment &environment);
  // brandedPublicKey - public key as server claims it is
  // hostAddress      - host's IP address as we know it
  // environment      - key policy and database
  // throws: if there is a problem with the key, this function should
  //         throw xSecurity


#endif // __KEYDB_H