| //======================================================================== |
| // |
| // SecurityHandler.cc |
| // |
| // 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) 2010, 2012, 2015, 2017, 2018, 2020-2022 Albert Astals Cid <aacid@kde.org> |
| // Copyright (C) 2013 Adrian Johnson <ajohnson@redneon.com> |
| // Copyright (C) 2014 Fabio D'Urso <fabiodurso@hotmail.it> |
| // Copyright (C) 2016 Alok Anand <alok4nand@gmail.com> |
| // |
| // 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 |
| // |
| //======================================================================== |
| |
| #include <config.h> |
| |
| #include "GooString.h" |
| #include "PDFDoc.h" |
| #include "Decrypt.h" |
| #include "Error.h" |
| #include "GlobalParams.h" |
| #include "SecurityHandler.h" |
| |
| #include <climits> |
| |
| //------------------------------------------------------------------------ |
| // SecurityHandler |
| //------------------------------------------------------------------------ |
| |
| SecurityHandler *SecurityHandler::make(PDFDoc *docA, Object *encryptDictA) |
| { |
| SecurityHandler *secHdlr; |
| |
| Object filterObj = encryptDictA->dictLookup("Filter"); |
| if (filterObj.isName("Standard")) { |
| secHdlr = new StandardSecurityHandler(docA, encryptDictA); |
| } else if (filterObj.isName()) { |
| error(errSyntaxError, -1, "Couldn't find the '{0:s}' security handler", filterObj.getName()); |
| secHdlr = nullptr; |
| } else { |
| error(errSyntaxError, -1, "Missing or invalid 'Filter' entry in encryption dictionary"); |
| secHdlr = nullptr; |
| } |
| return secHdlr; |
| } |
| |
| SecurityHandler::SecurityHandler(PDFDoc *docA) |
| { |
| doc = docA; |
| } |
| |
| SecurityHandler::~SecurityHandler() { } |
| |
| bool SecurityHandler::checkEncryption(const std::optional<GooString> &ownerPassword, const std::optional<GooString> &userPassword) |
| { |
| void *authData; |
| |
| if (ownerPassword || userPassword) { |
| authData = makeAuthData(ownerPassword, userPassword); |
| } else { |
| authData = nullptr; |
| } |
| const bool ok = authorize(authData); |
| if (authData) { |
| freeAuthData(authData); |
| } |
| if (!ok) { |
| if (!ownerPassword && !userPassword) { |
| return checkEncryption(GooString(), GooString()); |
| } else { |
| error(errCommandLine, -1, "Incorrect password"); |
| } |
| } |
| return ok; |
| } |
| |
| //------------------------------------------------------------------------ |
| // StandardSecurityHandler |
| //------------------------------------------------------------------------ |
| |
| class StandardAuthData |
| { |
| public: |
| StandardAuthData(GooString *ownerPasswordA, GooString *userPasswordA) |
| { |
| ownerPassword = ownerPasswordA; |
| userPassword = userPasswordA; |
| } |
| |
| ~StandardAuthData() |
| { |
| if (ownerPassword) { |
| delete ownerPassword; |
| } |
| if (userPassword) { |
| delete userPassword; |
| } |
| } |
| |
| StandardAuthData(const StandardAuthData &) = delete; |
| StandardAuthData &operator=(const StandardAuthData &) = delete; |
| |
| GooString *ownerPassword; |
| GooString *userPassword; |
| }; |
| |
| StandardSecurityHandler::StandardSecurityHandler(PDFDoc *docA, Object *encryptDictA) : SecurityHandler(docA) |
| { |
| ok = false; |
| fileID = nullptr; |
| ownerKey = nullptr; |
| userKey = nullptr; |
| ownerEnc = nullptr; |
| userEnc = nullptr; |
| fileKeyLength = 0; |
| encAlgorithm = cryptNone; |
| |
| Object versionObj = encryptDictA->dictLookup("V"); |
| Object revisionObj = encryptDictA->dictLookup("R"); |
| Object lengthObj = encryptDictA->dictLookup("Length"); |
| Object ownerKeyObj = encryptDictA->dictLookup("O"); |
| Object userKeyObj = encryptDictA->dictLookup("U"); |
| Object ownerEncObj = encryptDictA->dictLookup("OE"); |
| Object userEncObj = encryptDictA->dictLookup("UE"); |
| Object permObj = encryptDictA->dictLookup("P"); |
| if (permObj.isInt64()) { |
| unsigned int permUint = static_cast<unsigned int>(permObj.getInt64()); |
| int perms = permUint - UINT_MAX - 1; |
| permObj = Object(perms); |
| } |
| Object fileIDObj = doc->getXRef()->getTrailerDict()->dictLookup("ID"); |
| if (versionObj.isInt() && revisionObj.isInt() && permObj.isInt() && ownerKeyObj.isString() && userKeyObj.isString()) { |
| encVersion = versionObj.getInt(); |
| encRevision = revisionObj.getInt(); |
| if ((encRevision <= 4 && ownerKeyObj.getString()->getLength() >= 1 && userKeyObj.getString()->getLength() >= 1) |
| || ((encRevision == 5 || encRevision == 6) && |
| // the spec says 48 bytes, but Acrobat pads them out longer |
| ownerKeyObj.getString()->getLength() >= 48 && userKeyObj.getString()->getLength() >= 48 && ownerEncObj.isString() && ownerEncObj.getString()->getLength() == 32 && userEncObj.isString() |
| && userEncObj.getString()->getLength() == 32)) { |
| 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 = true; |
| //~ this currently only handles a subset of crypt filter functionality |
| //~ (in particular, it ignores the EFF entry in encryptDictA, and |
| //~ doesn't handle the case where StmF, StrF, and EFF are not all the |
| //~ same) |
| if ((encVersion == 4 || encVersion == 5) && (encRevision == 4 || encRevision == 5 || encRevision == 6)) { |
| Object cryptFiltersObj = encryptDictA->dictLookup("CF"); |
| Object streamFilterObj = encryptDictA->dictLookup("StmF"); |
| Object stringFilterObj = encryptDictA->dictLookup("StrF"); |
| if (cryptFiltersObj.isDict() && streamFilterObj.isName() && stringFilterObj.isName() && !strcmp(streamFilterObj.getName(), stringFilterObj.getName())) { |
| if (!strcmp(streamFilterObj.getName(), "Identity")) { |
| // no encryption on streams or strings |
| encVersion = encRevision = -1; |
| } else { |
| Object cryptFilterObj = cryptFiltersObj.dictLookup(streamFilterObj.getName()); |
| if (cryptFilterObj.isDict()) { |
| Object cfmObj = cryptFilterObj.dictLookup("CFM"); |
| if (cfmObj.isName("V2")) { |
| encVersion = 2; |
| encRevision = 3; |
| Object cfLengthObj = cryptFilterObj.dictLookup("Length"); |
| if (cfLengthObj.isInt()) { |
| //~ according to the spec, this should be cfLengthObj / 8 |
| fileKeyLength = cfLengthObj.getInt(); |
| } |
| } else if (cfmObj.isName("AESV2")) { |
| encVersion = 2; |
| encRevision = 3; |
| encAlgorithm = cryptAES; |
| Object cfLengthObj = cryptFilterObj.dictLookup("Length"); |
| if (cfLengthObj.isInt()) { |
| //~ according to the spec, this should be cfLengthObj / 8 |
| fileKeyLength = cfLengthObj.getInt(); |
| } |
| } else if (cfmObj.isName("AESV3")) { |
| encVersion = 5; |
| // let encRevision be 5 or 6 |
| encAlgorithm = cryptAES256; |
| Object cfLengthObj = cryptFilterObj.dictLookup("Length"); |
| if (cfLengthObj.isInt()) { |
| //~ according to the spec, this should be cfLengthObj / 8 |
| fileKeyLength = cfLengthObj.getInt(); |
| } |
| } |
| } |
| } |
| } |
| Object encryptMetadataObj = encryptDictA->dictLookup("EncryptMetadata"); |
| if (encryptMetadataObj.isBool()) { |
| encryptMetadata = encryptMetadataObj.getBool(); |
| } |
| } |
| permFlags = permObj.getInt(); |
| ownerKey = ownerKeyObj.getString()->copy(); |
| userKey = userKeyObj.getString()->copy(); |
| if (encVersion >= 1 && encVersion <= 2 && encRevision >= 2 && encRevision <= 3) { |
| if (fileIDObj.isArray()) { |
| Object fileIDObj1 = fileIDObj.arrayGet(0); |
| if (fileIDObj1.isString()) { |
| fileID = fileIDObj1.getString()->copy(); |
| } else { |
| fileID = new GooString(); |
| } |
| } else { |
| fileID = new GooString(); |
| } |
| if (fileKeyLength > 16 || fileKeyLength < 0) { |
| fileKeyLength = 16; |
| } |
| ok = true; |
| } else if (encVersion == 5 && (encRevision == 5 || encRevision == 6)) { |
| fileID = new GooString(); // unused for V=R=5 |
| if (ownerEncObj.isString() && userEncObj.isString()) { |
| ownerEnc = ownerEncObj.getString()->copy(); |
| userEnc = userEncObj.getString()->copy(); |
| if (fileKeyLength > 32 || fileKeyLength < 0) { |
| fileKeyLength = 32; |
| } |
| ok = true; |
| } else { |
| error(errSyntaxError, -1, "Weird encryption owner/user info"); |
| } |
| } else if (!(encVersion == -1 && encRevision == -1)) { |
| error(errUnimplemented, -1, "Unsupported version/revision ({0:d}/{1:d}) of Standard security handler", encVersion, encRevision); |
| } |
| |
| if (encRevision <= 4) { |
| // Adobe apparently zero-pads the U value (and maybe the O value?) |
| // if it's short |
| while (ownerKey->getLength() < 32) { |
| ownerKey->append((char)0x00); |
| } |
| while (userKey->getLength() < 32) { |
| userKey->append((char)0x00); |
| } |
| } |
| } else { |
| error(errSyntaxError, -1, |
| "Invalid encryption key length. version: {0:d} - revision: {1:d} - ownerKeyLength: {2:d} - userKeyLength: {3:d} - ownerEncIsString: {4:d} - ownerEncLength: {5:d} - userEncIsString: {6:d} - userEncLength: {7:d}", |
| encVersion, encRevision, ownerKeyObj.getString()->getLength(), userKeyObj.getString()->getLength(), ownerEncObj.isString(), ownerEncObj.isString() ? ownerEncObj.getString()->getLength() : -1, userEncObj.isString(), |
| userEncObj.isString() ? userEncObj.getString()->getLength() : -1); |
| } |
| } else { |
| error(errSyntaxError, -1, "Weird encryption info"); |
| } |
| } |
| |
| StandardSecurityHandler::~StandardSecurityHandler() |
| { |
| if (fileID) { |
| delete fileID; |
| } |
| if (ownerKey) { |
| delete ownerKey; |
| } |
| if (userKey) { |
| delete userKey; |
| } |
| if (ownerEnc) { |
| delete ownerEnc; |
| } |
| if (userEnc) { |
| delete userEnc; |
| } |
| } |
| |
| bool StandardSecurityHandler::isUnencrypted() const |
| { |
| if (!ok) { |
| return true; |
| } |
| return encVersion == -1 && encRevision == -1; |
| } |
| |
| void *StandardSecurityHandler::makeAuthData(const std::optional<GooString> &ownerPassword, const std::optional<GooString> &userPassword) |
| { |
| return new StandardAuthData(ownerPassword ? ownerPassword->copy() : nullptr, userPassword ? userPassword->copy() : nullptr); |
| } |
| |
| void StandardSecurityHandler::freeAuthData(void *authData) |
| { |
| delete (StandardAuthData *)authData; |
| } |
| |
| bool StandardSecurityHandler::authorize(void *authData) |
| { |
| GooString *ownerPassword, *userPassword; |
| |
| if (!ok) { |
| return false; |
| } |
| if (authData) { |
| ownerPassword = ((StandardAuthData *)authData)->ownerPassword; |
| userPassword = ((StandardAuthData *)authData)->userPassword; |
| } else { |
| ownerPassword = nullptr; |
| userPassword = nullptr; |
| } |
| if (!Decrypt::makeFileKey(encVersion, encRevision, fileKeyLength, ownerKey, userKey, ownerEnc, userEnc, permFlags, fileID, ownerPassword, userPassword, fileKey, encryptMetadata, &ownerPasswordOk)) { |
| return false; |
| } |
| return true; |
| } |
