poppler/SecurityHandler.h

//========================================================================
//
// SecurityHandler.h
//
// Copyright 2004 Glyph & Cog, LLC
//
//========================================================================

//========================================================================
//
// Modified under the Poppler project - http://poppler.freedesktop.org
//
// All changes made under the Poppler project to this file are licensed
// under GPL version 2 or later
//
// Copyright (C) 2012, 2018 Albert Astals Cid <aacid@kde.org>
//
// To see a description of the changes please see the Changelog file that
// came with your tarball or type make ChangeLog if you are building from git
//
//========================================================================

#ifndef SECURITYHANDLER_H
#define SECURITYHANDLER_H

#include "poppler-config.h"

#include "Object.h"

class GooString;
class PDFDoc;
struct XpdfSecurityHandler;

//------------------------------------------------------------------------
// SecurityHandler
//------------------------------------------------------------------------

class SecurityHandler {
public:

  static SecurityHandler *make(PDFDoc *docA, Object *encryptDictA);

  SecurityHandler(PDFDoc *docA);
  virtual ~SecurityHandler();

  SecurityHandler(const SecurityHandler &) = delete;
  SecurityHandler& operator=(const SecurityHandler &) = delete;

  // Returns true if the file is actually unencrypted.
  virtual bool isUnencrypted() { return false; }

  // Check the document's encryption.  If the document is encrypted,
  // this will first try <ownerPassword> and <userPassword> (in
  // "batch" mode), and if those fail, it will attempt to request a
  // password from the user.  This is the high-level function that
  // calls the lower level functions for the specific security handler
  // (requesting a password three times, etc.).  Returns true if the
  // document can be opened (if it's unencrypted, or if a correct
  // password is obtained); false otherwise (encrypted and no correct
  // password).
  bool checkEncryption(const GooString *ownerPassword,
			const GooString *userPassword);

  // Create authorization data for the specified owner and user
  // passwords.  If the security handler doesn't support "batch" mode,
  // this function should return NULL.
  virtual void *makeAuthData(const GooString *ownerPassword,
			     const GooString *userPassword) = 0;

  // Construct authorization data, typically by prompting the user for
  // a password.  Returns an authorization data object, or NULL to
  // cancel.
  virtual void *getAuthData() = 0;

  // Free the authorization data returned by makeAuthData or
  // getAuthData.
  virtual void freeAuthData(void *authData) = 0;

  // Attempt to authorize the document, using the supplied
  // authorization data (which may be NULL).  Returns true if
  // successful (i.e., if at least the right to open the document was
  // granted).
  virtual bool authorize(void *authData) = 0;

  // Return the various authorization parameters.  These are only
  // valid after authorize has returned true.
  virtual int getPermissionFlags() = 0;
  virtual bool getOwnerPasswordOk() = 0;
  virtual unsigned char *getFileKey() = 0;
  virtual int getFileKeyLength() = 0;
  virtual int getEncVersion() = 0;
  virtual int getEncRevision() = 0;
  virtual CryptAlgorithm getEncAlgorithm() = 0;

protected:

  PDFDoc *doc;
};

//------------------------------------------------------------------------
// StandardSecurityHandler
//------------------------------------------------------------------------

class StandardSecurityHandler: public SecurityHandler {
public:

  StandardSecurityHandler(PDFDoc *docA, Object *encryptDictA);
  ~StandardSecurityHandler();

  bool isUnencrypted() override;
  void *makeAuthData(const GooString *ownerPassword,
			     const GooString *userPassword) override;
  void *getAuthData() override;
  void freeAuthData(void *authData) override;
  bool authorize(void *authData) override;
  int getPermissionFlags() override { return permFlags; }
  bool getOwnerPasswordOk() override { return ownerPasswordOk; }
  unsigned char *getFileKey() override { return fileKey; }
  int getFileKeyLength() override { return fileKeyLength; }
  int getEncVersion() override { return encVersion; }
  int getEncRevision() override { return encRevision; }
  CryptAlgorithm getEncAlgorithm() override { return encAlgorithm; }

private:

  int permFlags;
  bool ownerPasswordOk;
  unsigned char fileKey[32];
  int fileKeyLength;
  int encVersion;
  int encRevision;
  bool encryptMetadata;
  CryptAlgorithm encAlgorithm;

  GooString *ownerKey, *userKey;
  GooString *ownerEnc, *userEnc;
  GooString *fileID;
  bool ok;
};

#endif