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tdegraphics/kpdf/xpdf/xpdf/SecurityHandler.cpp

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10 KiB

//========================================================================
//
// SecurityHandler.cpp
//
// Copyright 2004 Glyph & Cog, LLC
//
//========================================================================
#include <aconf.h>
#ifdef USE_GCC_PRAGMAS
#pragma implementation
#endif
#include "GString.h"
#include "PDFDoc.h"
#include "Decrypt.h"
#include "Error.h"
#include "GlobalParams.h"
#if HAVE_XPDFCORE
# include "XPDFCore.h"
#elif HAVE_WINPDFCORE
# include "WinPDFCore.h"
#endif
#ifdef ENABLE_PLUGINS
# include "XpdfPluginAPI.h"
#endif
#include "SecurityHandler.h"
//------------------------------------------------------------------------
// SecurityHandler
//------------------------------------------------------------------------
SecurityHandler *SecurityHandler::make(PDFDoc *docA, Object *encryptDictA) {
Object filterObj;
SecurityHandler *secHdlr;
#ifdef ENABLE_PLUGINS
XpdfSecurityHandler *xsh;
#endif
encryptDictA->dictLookup("Filter", &filterObj);
if (filterObj.isName("Standard")) {
secHdlr = new StandardSecurityHandler(docA, encryptDictA);
} else if (filterObj.isName()) {
#ifdef ENABLE_PLUGINS
if ((xsh = globalParams->getSecurityHandler(filterObj.getName()))) {
secHdlr = new ExternalSecurityHandler(docA, encryptDictA, xsh);
} else {
#endif
error(-1, "Couldn't find the '%s' security handler",
filterObj.getName());
secHdlr = NULL;
#ifdef ENABLE_PLUGINS
}
#endif
} else {
error(-1, "Missing or invalid 'Filter' entry in encryption dictionary");
secHdlr = NULL;
}
filterObj.free();
return secHdlr;
}
SecurityHandler::SecurityHandler(PDFDoc *docA) {
doc = docA;
}
SecurityHandler::~SecurityHandler() {
}
GBool SecurityHandler::checkEncryption(GString *ownerPassword,
GString *userPassword) {
void *authData;
GBool ok;
int i;
if (ownerPassword || userPassword) {
authData = makeAuthData(ownerPassword, userPassword);
} else {
authData = NULL;
}
ok = authorize(authData);
if (authData) {
freeAuthData(authData);
}
for (i = 0; !ok && i < 3; ++i) {
if (!(authData = getAuthData())) {
break;
}
ok = authorize(authData);
if (authData) {
freeAuthData(authData);
}
}
if (!ok) {
error(-1, "Incorrect password");
}
return ok;
}
//------------------------------------------------------------------------
// StandardSecurityHandler
//------------------------------------------------------------------------
class StandardAuthData {
public:
StandardAuthData(GString *ownerPasswordA, GString *userPasswordA) {
ownerPassword = ownerPasswordA;
userPassword = userPasswordA;
}
~StandardAuthData() {
if (ownerPassword) {
delete ownerPassword;
}
if (userPassword) {
delete userPassword;
}
}
GString *ownerPassword;
GString *userPassword;
};
StandardSecurityHandler::StandardSecurityHandler(PDFDoc *docA,
Object *encryptDictA):
SecurityHandler(docA)
{
Object versionObj, revisionObj, lengthObj;
Object ownerKeyObj, userKeyObj, permObj, fileIDObj;
Object fileIDObj1;
Object cryptFiltersObj, streamFilterObj, stringFilterObj;
Object cryptFilterObj, cfmObj, cfLengthObj;
Object encryptMetadataObj;
ok = gFalse;
fileID = NULL;
ownerKey = NULL;
userKey = NULL;
encryptDictA->dictLookup("V", &versionObj);
encryptDictA->dictLookup("R", &revisionObj);
encryptDictA->dictLookup("Length", &lengthObj);
encryptDictA->dictLookup("O", &ownerKeyObj);
encryptDictA->dictLookup("U", &userKeyObj);
encryptDictA->dictLookup("P", &permObj);
doc->getXRef()->getTrailerDict()->dictLookup("ID", &fileIDObj);
if (versionObj.isInt() &&
revisionObj.isInt() &&
ownerKeyObj.isString() && ownerKeyObj.getString()->getLength() == 32 &&
userKeyObj.isString() && userKeyObj.getString()->getLength() == 32 &&
permObj.isInt()) {
encVersion = versionObj.getInt();
encRevision = revisionObj.getInt();
encAlgorithm = cryptRC4;
// revision 2 forces a 40-bit key - some buggy PDF generators
// set the Length value incorrectly
if (encRevision == 2 || !lengthObj.isInt()) {
fileKeyLength = 5;
} else {
fileKeyLength = lengthObj.getInt() / 8;
}
encryptMetadata = gTrue;
//~ this currently only handles a subset of crypt filter functionality
if (encVersion == 4 && encRevision == 4) {
encryptDictA->dictLookup("CF", &cryptFiltersObj);
encryptDictA->dictLookup("StmF", &streamFilterObj);
encryptDictA->dictLookup("StrF", &stringFilterObj);
if (cryptFiltersObj.isDict() &&
streamFilterObj.isName() &&
stringFilterObj.isName() &&
!strcmp(streamFilterObj.getName(), stringFilterObj.getName())) {
if (cryptFiltersObj.dictLookup(streamFilterObj.getName(),
&cryptFilterObj)->isDict()) {
cryptFilterObj.dictLookup("CFM", &cfmObj);
if (cfmObj.isName("V2")) {
encVersion = 2;
encRevision = 3;
if (cryptFilterObj.dictLookup("Length", &cfLengthObj)->isInt()) {
//~ according to the spec, this should be cfLengthObj / 8
fileKeyLength = cfLengthObj.getInt();
}
cfLengthObj.free();
} else if (cfmObj.isName("AESV2")) {
encVersion = 2;
encRevision = 3;
encAlgorithm = cryptAES;
if (cryptFilterObj.dictLookup("Length", &cfLengthObj)->isInt()) {
//~ according to the spec, this should be cfLengthObj / 8
fileKeyLength = cfLengthObj.getInt();
}
cfLengthObj.free();
}
cfmObj.free();
}
cryptFilterObj.free();
}
stringFilterObj.free();
streamFilterObj.free();
cryptFiltersObj.free();
if (encryptDictA->dictLookup("EncryptMetadata",
&encryptMetadataObj)->isBool()) {
encryptMetadata = encryptMetadataObj.getBool();
}
encryptMetadataObj.free();
}
permFlags = permObj.getInt();
ownerKey = ownerKeyObj.getString()->copy();
userKey = userKeyObj.getString()->copy();
if (encVersion >= 1 && encVersion <= 2 &&
encRevision >= 2 && encRevision <= 3) {
if (fileIDObj.isArray()) {
if (fileIDObj.arrayGet(0, &fileIDObj1)->isString()) {
fileID = fileIDObj1.getString()->copy();
} else {
fileID = new GString();
}
fileIDObj1.free();
} else {
fileID = new GString();
}
ok = gTrue;
} else {
error(-1, "Unsupported version/revision (%d/%d) of Standard security handler",
encVersion, encRevision);
}
} else {
error(-1, "Weird encryption info");
}
if (fileKeyLength > 16) {
fileKeyLength = 16;
}
fileIDObj.free();
permObj.free();
userKeyObj.free();
ownerKeyObj.free();
lengthObj.free();
revisionObj.free();
versionObj.free();
}
StandardSecurityHandler::~StandardSecurityHandler() {
if (fileID) {
delete fileID;
}
if (ownerKey) {
delete ownerKey;
}
if (userKey) {
delete userKey;
}
}
void *StandardSecurityHandler::makeAuthData(GString *ownerPassword,
GString *userPassword) {
return new StandardAuthData(ownerPassword ? ownerPassword->copy()
: (GString *)NULL,
userPassword ? userPassword->copy()
: (GString *)NULL);
}
void *StandardSecurityHandler::getAuthData() {
#if HAVE_XPDFCORE
XPDFCore *core;
GString *password;
if (!(core = (XPDFCore *)doc->getGUIData()) ||
!(password = core->getPassword())) {
return NULL;
}
return new StandardAuthData(password, password->copy());
#elif HAVE_WINPDFCORE
WinPDFCore *core;
GString *password;
if (!(core = (WinPDFCore *)doc->getGUIData()) ||
!(password = core->getPassword())) {
return NULL;
}
return new StandardAuthData(password, password->copy());
#else
return NULL;
#endif
}
void StandardSecurityHandler::freeAuthData(void *authData) {
delete (StandardAuthData *)authData;
}
GBool StandardSecurityHandler::authorize(void *authData) {
GString *ownerPassword, *userPassword;
if (!ok) {
return gFalse;
}
if (authData) {
ownerPassword = ((StandardAuthData *)authData)->ownerPassword;
userPassword = ((StandardAuthData *)authData)->userPassword;
} else {
ownerPassword = NULL;
userPassword = NULL;
}
if (!Decrypt::makeFileKey(encVersion, encRevision, fileKeyLength,
ownerKey, userKey, permFlags, fileID,
ownerPassword, userPassword, fileKey,
encryptMetadata, &ownerPasswordOk)) {
return gFalse;
}
return gTrue;
}
#ifdef ENABLE_PLUGINS
//------------------------------------------------------------------------
// ExternalSecurityHandler
//------------------------------------------------------------------------
ExternalSecurityHandler::ExternalSecurityHandler(PDFDoc *docA,
Object *encryptDictA,
XpdfSecurityHandler *xshA):
SecurityHandler(docA)
{
encryptDictA->copy(&encryptDict);
xsh = xshA;
encAlgorithm = cryptRC4; //~ this should be obtained via getKey
ok = gFalse;
if (!(*xsh->newDoc)(xsh->handlerData, (XpdfDoc)docA,
(XpdfObject)encryptDictA, &docData)) {
return;
}
ok = gTrue;
}
ExternalSecurityHandler::~ExternalSecurityHandler() {
(*xsh->freeDoc)(xsh->handlerData, docData);
encryptDict.free();
}
void *ExternalSecurityHandler::makeAuthData(GString *ownerPassword,
GString *userPassword) {
char *opw, *upw;
void *authData;
opw = ownerPassword ? ownerPassword->getCString() : (char *)NULL;
upw = userPassword ? userPassword->getCString() : (char *)NULL;
if (!(*xsh->makeAuthData)(xsh->handlerData, docData, opw, upw, &authData)) {
return NULL;
}
return authData;
}
void *ExternalSecurityHandler::getAuthData() {
void *authData;
if (!(*xsh->getAuthData)(xsh->handlerData, docData, &authData)) {
return NULL;
}
return authData;
}
void ExternalSecurityHandler::freeAuthData(void *authData) {
(*xsh->freeAuthData)(xsh->handlerData, docData, authData);
}
GBool ExternalSecurityHandler::authorize(void *authData) {
char *key;
int length;
if (!ok) {
return gFalse;
}
permFlags = (*xsh->authorize)(xsh->handlerData, docData, authData);
if (!(permFlags & xpdfPermissionOpen)) {
return gFalse;
}
if (!(*xsh->getKey)(xsh->handlerData, docData, &key, &length, &encVersion)) {
return gFalse;
}
if ((fileKeyLength = length) > 16) {
fileKeyLength = 16;
}
memcpy(fileKey, key, fileKeyLength);
(*xsh->freeKey)(xsh->handlerData, docData, key, length);
return gTrue;
}
#endif // ENABLE_PLUGINS