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Code Issues Releases Wiki Activity
8ccd3a8a89
qpdf/libqpdf/QPDFWriter.cc
Jay Berkenbilt 8ccd3a8a89 Mark weak encryption with API changes (fixes #576)
2022-04-30 17:24:15 -04:00

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#include <qpdf/qpdf-config.h> // include first for large file support
#include <qpdf/QPDFWriter.hh>
#include <qpdf/MD5.hh>
#include <qpdf/Pl_AES_PDF.hh>
#include <qpdf/Pl_Count.hh>
#include <qpdf/Pl_Discard.hh>
#include <qpdf/Pl_Flate.hh>
#include <qpdf/Pl_MD5.hh>
#include <qpdf/Pl_PNGFilter.hh>
#include <qpdf/Pl_RC4.hh>
#include <qpdf/Pl_StdioFile.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/RC4.hh>
#include <assert.h>
#include <qpdf/QIntC.hh>
#include <qpdf/QPDF.hh>
#include <qpdf/QPDFObjectHandle.hh>
#include <qpdf/QPDF_Name.hh>
#include <qpdf/QPDF_String.hh>
#include <algorithm>
#include <stdlib.h>
QPDFWriter::Members::Members(QPDF& pdf) :
pdf(pdf),
filename("unspecified"),
file(0),
close_file(false),
buffer_pipeline(0),
output_buffer(0),
normalize_content_set(false),
normalize_content(false),
compress_streams(true),
compress_streams_set(false),
stream_decode_level(qpdf_dl_none),
stream_decode_level_set(false),
recompress_flate(false),
qdf_mode(false),
preserve_unreferenced_objects(false),
newline_before_endstream(false),
static_id(false),
suppress_original_object_ids(false),
direct_stream_lengths(true),
encrypted(false),
preserve_encryption(true),
linearized(false),
pclm(false),
object_stream_mode(qpdf_o_preserve),
encrypt_metadata(true),
encrypt_use_aes(false),
encryption_V(0),
encryption_R(0),
final_extension_level(0),
min_extension_level(0),
forced_extension_level(0),
encryption_dict_objid(0),
pipeline(0),
next_objid(1),
cur_stream_length_id(0),
cur_stream_length(0),
added_newline(false),
max_ostream_index(0),
next_stack_id(0),
deterministic_id(false),
md5_pipeline(0),
did_write_setup(false),
events_expected(0),
events_seen(0),
next_progress_report(0)
{
}
QPDFWriter::Members::~Members()
{
if (file && close_file) {
fclose(file);
}
delete output_buffer;
}
QPDFWriter::QPDFWriter(QPDF& pdf) :
m(new Members(pdf))
{
}
QPDFWriter::QPDFWriter(QPDF& pdf, char const* filename) :
m(new Members(pdf))
{
setOutputFilename(filename);
}
QPDFWriter::QPDFWriter(
QPDF& pdf, char const* description, FILE* file, bool close_file) :
m(new Members(pdf))
{
setOutputFile(description, file, close_file);
}
void
QPDFWriter::setOutputFilename(char const* filename)
{
char const* description = filename;
FILE* f = 0;
bool close_file = false;
if (filename == 0) {
description = "standard output";
QTC::TC("qpdf", "QPDFWriter write to stdout");
f = stdout;
QUtil::binary_stdout();
} else {
QTC::TC("qpdf", "QPDFWriter write to file");
f = QUtil::safe_fopen(filename, "wb+");
close_file = true;
}
setOutputFile(description, f, close_file);
}
void
QPDFWriter::setOutputFile(char const* description, FILE* file, bool close_file)
{
this->m->filename = description;
this->m->file = file;
this->m->close_file = close_file;
std::shared_ptr<Pipeline> p =
std::make_shared<Pl_StdioFile>("qpdf output", file);
this->m->to_delete.push_back(p);
initializePipelineStack(p.get());
}
void
QPDFWriter::setOutputMemory()
{
this->m->filename = "memory buffer";
this->m->buffer_pipeline = new Pl_Buffer("qpdf output");
this->m->to_delete.push_back(
std::shared_ptr<Pipeline>(this->m->buffer_pipeline));
initializePipelineStack(this->m->buffer_pipeline);
}
Buffer*
QPDFWriter::getBuffer()
{
Buffer* result = this->m->output_buffer;
this->m->output_buffer = 0;
return result;
}
std::shared_ptr<Buffer>
QPDFWriter::getBufferSharedPointer()
{
return std::shared_ptr<Buffer>(getBuffer());
}
void
QPDFWriter::setOutputPipeline(Pipeline* p)
{
this->m->filename = "custom pipeline";
initializePipelineStack(p);
}
void
QPDFWriter::setObjectStreamMode(qpdf_object_stream_e mode)
{
this->m->object_stream_mode = mode;
}
void
QPDFWriter::setStreamDataMode(qpdf_stream_data_e mode)
{
switch (mode) {
case qpdf_s_uncompress:
this->m->stream_decode_level =
std::max(qpdf_dl_generalized, this->m->stream_decode_level);
this->m->compress_streams = false;
break;
case qpdf_s_preserve:
this->m->stream_decode_level = qpdf_dl_none;
this->m->compress_streams = false;
break;
case qpdf_s_compress:
this->m->stream_decode_level =
std::max(qpdf_dl_generalized, this->m->stream_decode_level);
this->m->compress_streams = true;
break;
}
this->m->stream_decode_level_set = true;
this->m->compress_streams_set = true;
}
void
QPDFWriter::setCompressStreams(bool val)
{
this->m->compress_streams = val;
this->m->compress_streams_set = true;
}
void
QPDFWriter::setDecodeLevel(qpdf_stream_decode_level_e val)
{
this->m->stream_decode_level = val;
this->m->stream_decode_level_set = true;
}
void
QPDFWriter::setRecompressFlate(bool val)
{
this->m->recompress_flate = val;
}
void
QPDFWriter::setContentNormalization(bool val)
{
this->m->normalize_content_set = true;
this->m->normalize_content = val;
}
void
QPDFWriter::setQDFMode(bool val)
{
this->m->qdf_mode = val;
}
void
QPDFWriter::setPreserveUnreferencedObjects(bool val)
{
this->m->preserve_unreferenced_objects = val;
}
void
QPDFWriter::setNewlineBeforeEndstream(bool val)
{
this->m->newline_before_endstream = val;
}
void
QPDFWriter::setMinimumPDFVersion(
std::string const& version, int extension_level)
{
bool set_version = false;
bool set_extension_level = false;
if (this->m->min_pdf_version.empty()) {
set_version = true;
set_extension_level = true;
} else {
int old_major = 0;
int old_minor = 0;
int min_major = 0;
int min_minor = 0;
parseVersion(version, old_major, old_minor);
parseVersion(this->m->min_pdf_version, min_major, min_minor);
int compare =
compareVersions(old_major, old_minor, min_major, min_minor);
if (compare > 0) {
QTC::TC(
"qpdf",
"QPDFWriter increasing minimum version",
extension_level == 0 ? 0 : 1);
set_version = true;
set_extension_level = true;
} else if (compare == 0) {
if (extension_level > this->m->min_extension_level) {
QTC::TC("qpdf", "QPDFWriter increasing extension level");
set_extension_level = true;
}
}
}
if (set_version) {
this->m->min_pdf_version = version;
}
if (set_extension_level) {
this->m->min_extension_level = extension_level;
}
}
void
QPDFWriter::setMinimumPDFVersion(PDFVersion const& v)
{
std::string version;
int extension_level;
v.getVersion(version, extension_level);
setMinimumPDFVersion(version, extension_level);
}
void
QPDFWriter::forcePDFVersion(std::string const& version, int extension_level)
{
this->m->forced_pdf_version = version;
this->m->forced_extension_level = extension_level;
}
void
QPDFWriter::setExtraHeaderText(std::string const& text)
{
this->m->extra_header_text = text;
if ((this->m->extra_header_text.length() > 0) &&
(*(this->m->extra_header_text.rbegin()) != '\n')) {
QTC::TC("qpdf", "QPDFWriter extra header text add newline");
this->m->extra_header_text += "\n";
} else {
QTC::TC("qpdf", "QPDFWriter extra header text no newline");
}
}
void
QPDFWriter::setStaticID(bool val)
{
this->m->static_id = val;
}
void
QPDFWriter::setDeterministicID(bool val)
{
this->m->deterministic_id = val;
}
void
QPDFWriter::setStaticAesIV(bool val)
{
if (val) {
Pl_AES_PDF::useStaticIV();
}
}
void
QPDFWriter::setSuppressOriginalObjectIDs(bool val)
{
this->m->suppress_original_object_ids = val;
}
void
QPDFWriter::setPreserveEncryption(bool val)
{
this->m->preserve_encryption = val;
}
void
QPDFWriter::setLinearization(bool val)
{
this->m->linearized = val;
if (val) {
this->m->pclm = false;
}
}
void
QPDFWriter::setLinearizationPass1Filename(std::string const& filename)
{
this->m->lin_pass1_filename = filename;
}
void
QPDFWriter::setPCLm(bool val)
{
this->m->pclm = val;
if (val) {
this->m->linearized = false;
}
}
void
QPDFWriter::setR2EncryptionParametersInsecure(
char const* user_password,
char const* owner_password,
bool allow_print,
bool allow_modify,
bool allow_extract,
bool allow_annotate)
{
std::set<int> clear;
if (!allow_print) {
clear.insert(3);
}
if (!allow_modify) {
clear.insert(4);
}
if (!allow_extract) {
clear.insert(5);
}
if (!allow_annotate) {
clear.insert(6);
}
setEncryptionParameters(user_password, owner_password, 1, 2, 5, clear);
}
void
QPDFWriter::setR3EncryptionParametersInsecure(
char const* user_password,
char const* owner_password,
bool allow_accessibility,
bool allow_extract,
bool allow_assemble,
bool allow_annotate_and_form,
bool allow_form_filling,
bool allow_modify_other,
qpdf_r3_print_e print)
{
std::set<int> clear;
interpretR3EncryptionParameters(
clear,
user_password,
owner_password,
allow_accessibility,
allow_extract,
allow_assemble,
allow_annotate_and_form,
allow_form_filling,
allow_modify_other,
print,
qpdf_r3m_all);
setEncryptionParameters(user_password, owner_password, 2, 3, 16, clear);
}
void
QPDFWriter::setR4EncryptionParametersInsecure(
char const* user_password,
char const* owner_password,
bool allow_accessibility,
bool allow_extract,
bool allow_assemble,
bool allow_annotate_and_form,
bool allow_form_filling,
bool allow_modify_other,
qpdf_r3_print_e print,
bool encrypt_metadata,
bool use_aes)
{
std::set<int> clear;
interpretR3EncryptionParameters(
clear,
user_password,
owner_password,
allow_accessibility,
allow_extract,
allow_assemble,
allow_annotate_and_form,
allow_form_filling,
allow_modify_other,
print,
qpdf_r3m_all);
this->m->encrypt_use_aes = use_aes;
this->m->encrypt_metadata = encrypt_metadata;
setEncryptionParameters(user_password, owner_password, 4, 4, 16, clear);
}
void
QPDFWriter::setR5EncryptionParameters(
char const* user_password,
char const* owner_password,
bool allow_accessibility,
bool allow_extract,
bool allow_assemble,
bool allow_annotate_and_form,
bool allow_form_filling,
bool allow_modify_other,
qpdf_r3_print_e print,
bool encrypt_metadata)
{
std::set<int> clear;
interpretR3EncryptionParameters(
clear,
user_password,
owner_password,
allow_accessibility,
allow_extract,
allow_assemble,
allow_annotate_and_form,
allow_form_filling,
allow_modify_other,
print,
qpdf_r3m_all);
this->m->encrypt_use_aes = true;
this->m->encrypt_metadata = encrypt_metadata;
setEncryptionParameters(user_password, owner_password, 5, 5, 32, clear);
}
void
QPDFWriter::setR6EncryptionParameters(
char const* user_password,
char const* owner_password,
bool allow_accessibility,
bool allow_extract,
bool allow_assemble,
bool allow_annotate_and_form,
bool allow_form_filling,
bool allow_modify_other,
qpdf_r3_print_e print,
bool encrypt_metadata)
{
std::set<int> clear;
interpretR3EncryptionParameters(
clear,
user_password,
owner_password,
allow_accessibility,
allow_extract,
allow_assemble,
allow_annotate_and_form,
allow_form_filling,
allow_modify_other,
print,
qpdf_r3m_all);
this->m->encrypt_use_aes = true;
this->m->encrypt_metadata = encrypt_metadata;
setEncryptionParameters(user_password, owner_password, 5, 6, 32, clear);
}
void
QPDFWriter::interpretR3EncryptionParameters(
std::set<int>& clear,
char const* user_password,
char const* owner_password,
bool allow_accessibility,
bool allow_extract,
bool allow_assemble,
bool allow_annotate_and_form,
bool allow_form_filling,
bool allow_modify_other,
qpdf_r3_print_e print,
qpdf_r3_modify_e modify)
{
// Acrobat 5 security options:
// Checkboxes:
// Enable Content Access for the Visually Impaired
// Allow Content Copying and Extraction
// Allowed changes menu:
// None
// Only Document Assembly
// Only Form Field Fill-in or Signing
// Comment Authoring, Form Field Fill-in or Signing
// General Editing, Comment and Form Field Authoring
// Allowed printing menu:
// None
// Low Resolution
// Full printing
// Meanings of bits in P when R >= 3
//
// 3: low-resolution printing
// 4: document modification except as controlled by 6, 9, and 11
// 5: extraction
// 6: add/modify annotations (comment), fill in forms
// if 4+6 are set, also allows modification of form fields
// 9: fill in forms even if 6 is clear
// 10: accessibility; ignored by readers, should always be set
// 11: document assembly even if 4 is clear
// 12: high-resolution printing
if (!allow_accessibility) {
// setEncryptionParameters sets this if R > 3
clear.insert(10);
}
if (!allow_extract) {
clear.insert(5);
}
// Note: these switch statements all "fall through" (no break
// statements). Each option clears successively more access bits.
switch (print) {
case qpdf_r3p_none:
clear.insert(3); // any printing
case qpdf_r3p_low:
clear.insert(12); // high resolution printing
case qpdf_r3p_full:
break;
// no default so gcc warns for missing cases
}
// Modify options. The qpdf_r3_modify_e options control groups of
// bits and lack the full flexibility of the spec. This is
// unfortunate, but it's been in the API for ages, and we're stuck
// with it. See also allow checks below to control the bits
// individually.
// NOT EXERCISED IN TEST SUITE
switch (modify) {
case qpdf_r3m_none:
clear.insert(11); // document assembly
case qpdf_r3m_assembly:
clear.insert(9); // filling in form fields
case qpdf_r3m_form:
clear.insert(6); // modify annotations, fill in form fields
case qpdf_r3m_annotate:
clear.insert(4); // other modifications
case qpdf_r3m_all:
break;
// no default so gcc warns for missing cases
}
// END NOT EXERCISED IN TEST SUITE
if (!allow_assemble) {
clear.insert(11);
}
if (!allow_annotate_and_form) {
clear.insert(6);
}
if (!allow_form_filling) {
clear.insert(9);
}
if (!allow_modify_other) {
clear.insert(4);
}
}
void
QPDFWriter::setEncryptionParameters(
char const* user_password,
char const* owner_password,
int V,
int R,
int key_len,
std::set<int>& bits_to_clear)
{
// PDF specification refers to bits with the low bit numbered 1.
// We have to convert this into a bit field.
// Specification always requires bits 1 and 2 to be cleared.
bits_to_clear.insert(1);
bits_to_clear.insert(2);
if (R > 3) {
// Bit 10 is deprecated and should always be set. This used
// to mean accessibility. There is no way to disable
// accessibility with R > 3.
bits_to_clear.erase(10);
}
int P = 0;
// Create the complement of P, then invert.
for (int b: bits_to_clear) {
P |= (1 << (b - 1));
}
P = ~P;
generateID();
std::string O;
std::string U;
std::string OE;
std::string UE;
std::string Perms;
std::string encryption_key;
if (V < 5) {
QPDF::compute_encryption_O_U(
user_password,
owner_password,
V,
R,
key_len,
P,
this->m->encrypt_metadata,
this->m->id1,
O,
U);
} else {
QPDF::compute_encryption_parameters_V5(
user_password,
owner_password,
V,
R,
key_len,
P,
this->m->encrypt_metadata,
this->m->id1,
encryption_key,
O,
U,
OE,
UE,
Perms);
}
setEncryptionParametersInternal(
V,
R,
key_len,
P,
O,
U,
OE,
UE,
Perms,
this->m->id1,
user_password,
encryption_key);
}
void
QPDFWriter::copyEncryptionParameters(QPDF& qpdf)
{
this->m->preserve_encryption = false;
QPDFObjectHandle trailer = qpdf.getTrailer();
if (trailer.hasKey("/Encrypt")) {
generateID();
this->m->id1 = trailer.getKey("/ID").getArrayItem(0).getStringValue();
QPDFObjectHandle encrypt = trailer.getKey("/Encrypt");
int V = encrypt.getKey("/V").getIntValueAsInt();
int key_len = 5;
if (V > 1) {
key_len = encrypt.getKey("/Length").getIntValueAsInt() / 8;
}
if (encrypt.hasKey("/EncryptMetadata") &&
encrypt.getKey("/EncryptMetadata").isBool()) {
this->m->encrypt_metadata =
encrypt.getKey("/EncryptMetadata").getBoolValue();
}
if (V >= 4) {
// When copying encryption parameters, use AES even if the
// original file did not. Acrobat doesn't create files
// with V >= 4 that don't use AES, and the logic of
// figuring out whether AES is used or not is complicated
// with /StmF, /StrF, and /EFF all potentially having
// different values.
this->m->encrypt_use_aes = true;
}
QTC::TC(
"qpdf",
"QPDFWriter copy encrypt metadata",
this->m->encrypt_metadata ? 0 : 1);
QTC::TC(
"qpdf",
"QPDFWriter copy use_aes",
this->m->encrypt_use_aes ? 0 : 1);
std::string OE;
std::string UE;
std::string Perms;
std::string encryption_key;
if (V >= 5) {
QTC::TC("qpdf", "QPDFWriter copy V5");
OE = encrypt.getKey("/OE").getStringValue();
UE = encrypt.getKey("/UE").getStringValue();
Perms = encrypt.getKey("/Perms").getStringValue();
encryption_key = qpdf.getEncryptionKey();
}
setEncryptionParametersInternal(
V,
encrypt.getKey("/R").getIntValueAsInt(),
key_len,
static_cast<int>(encrypt.getKey("/P").getIntValue()),
encrypt.getKey("/O").getStringValue(),
encrypt.getKey("/U").getStringValue(),
OE,
UE,
Perms,
this->m->id1, // this->m->id1 == the other file's id1
qpdf.getPaddedUserPassword(),
encryption_key);
}
}
void
QPDFWriter::disableIncompatibleEncryption(
int major, int minor, int extension_level)
{
if (!this->m->encrypted) {
return;
}
bool disable = false;
if (compareVersions(major, minor, 1, 3) < 0) {
disable = true;
} else {
int V =
QUtil::string_to_int(this->m->encryption_dictionary["/V"].c_str());
int R =
QUtil::string_to_int(this->m->encryption_dictionary["/R"].c_str());
if (compareVersions(major, minor, 1, 4) < 0) {
if ((V > 1) || (R > 2)) {
disable = true;
}
} else if (compareVersions(major, minor, 1, 5) < 0) {
if ((V > 2) || (R > 3)) {
disable = true;
}
} else if (compareVersions(major, minor, 1, 6) < 0) {
if (this->m->encrypt_use_aes) {
disable = true;
}
} else if (
(compareVersions(major, minor, 1, 7) < 0) ||
((compareVersions(major, minor, 1, 7) == 0) &&
extension_level < 3)) {
if ((V >= 5) || (R >= 5)) {
disable = true;
}
}
}
if (disable) {
QTC::TC("qpdf", "QPDFWriter forced version disabled encryption");
this->m->encrypted = false;
}
}
void
QPDFWriter::parseVersion(
std::string const& version, int& major, int& minor) const
{
major = QUtil::string_to_int(version.c_str());
minor = 0;
size_t p = version.find('.');
if ((p != std::string::npos) && (version.length() > p)) {
minor = QUtil::string_to_int(version.substr(p + 1).c_str());
}
std::string tmp =
QUtil::int_to_string(major) + "." + QUtil::int_to_string(minor);
if (tmp != version) {
// The version number in the input is probably invalid. This
// happens with some files that are designed to exercise bugs,
// such as files in the fuzzer corpus. Unfortunately
// QPDFWriter doesn't have a way to give a warning, so we just
// ignore this case.
}
}
int
QPDFWriter::compareVersions(
int major1, int minor1, int major2, int minor2) const
{
if (major1 < major2) {
return -1;
} else if (major1 > major2) {
return 1;
} else if (minor1 < minor2) {
return -1;
} else if (minor1 > minor2) {
return 1;
} else {
return 0;
}
}
void
QPDFWriter::setEncryptionParametersInternal(
int V,
int R,
int key_len,
int P,
std::string const& O,
std::string const& U,
std::string const& OE,
std::string const& UE,
std::string const& Perms,
std::string const& id1,
std::string const& user_password,
std::string const& encryption_key)
{
this->m->encryption_V = V;
this->m->encryption_R = R;
this->m->encryption_dictionary["/Filter"] = "/Standard";
this->m->encryption_dictionary["/V"] = QUtil::int_to_string(V);
this->m->encryption_dictionary["/Length"] =
QUtil::int_to_string(key_len * 8);
this->m->encryption_dictionary["/R"] = QUtil::int_to_string(R);
this->m->encryption_dictionary["/P"] = QUtil::int_to_string(P);
this->m->encryption_dictionary["/O"] = QPDF_String(O).unparse(true);
this->m->encryption_dictionary["/U"] = QPDF_String(U).unparse(true);
if (V >= 5) {
this->m->encryption_dictionary["/OE"] = QPDF_String(OE).unparse(true);
this->m->encryption_dictionary["/UE"] = QPDF_String(UE).unparse(true);
this->m->encryption_dictionary["/Perms"] =
QPDF_String(Perms).unparse(true);
}
if (R >= 6) {
setMinimumPDFVersion("1.7", 8);
} else if (R == 5) {
setMinimumPDFVersion("1.7", 3);
} else if (R == 4) {
setMinimumPDFVersion(this->m->encrypt_use_aes ? "1.6" : "1.5");
} else if (R == 3) {
setMinimumPDFVersion("1.4");
} else {
setMinimumPDFVersion("1.3");
}
if ((R >= 4) && (!this->m->encrypt_metadata)) {
this->m->encryption_dictionary["/EncryptMetadata"] = "false";
}
if ((V == 4) || (V == 5)) {
// The spec says the value for the crypt filter key can be
// anything, and xpdf seems to agree. However, Adobe Reader
// won't open our files unless we use /StdCF.
this->m->encryption_dictionary["/StmF"] = "/StdCF";
this->m->encryption_dictionary["/StrF"] = "/StdCF";
std::string method =
(this->m->encrypt_use_aes ? ((V < 5) ? "/AESV2" : "/AESV3")
: "/V2");
// The PDF spec says the /Length key is optional, but the PDF
// previewer on some versions of MacOS won't open encrypted
// files without it.
this->m->encryption_dictionary["/CF"] =
"<< /StdCF << /AuthEvent /DocOpen /CFM " + method + " /Length " +
std::string((V < 5) ? "16" : "32") + " >> >>";
}
this->m->encrypted = true;
QPDF::EncryptionData encryption_data(
V, R, key_len, P, O, U, OE, UE, Perms, id1, this->m->encrypt_metadata);
if (V < 5) {
this->m->encryption_key =
QPDF::compute_encryption_key(user_password, encryption_data);
} else {
this->m->encryption_key = encryption_key;
}
}
void
QPDFWriter::setDataKey(int objid)
{
this->m->cur_data_key = QPDF::compute_data_key(
this->m->encryption_key,
objid,
0,
this->m->encrypt_use_aes,
this->m->encryption_V,
this->m->encryption_R);
}
unsigned int
QPDFWriter::bytesNeeded(long long n)
{
unsigned int bytes = 0;
while (n) {
++bytes;
n >>= 8;
}
return bytes;
}
void
QPDFWriter::writeBinary(unsigned long long val, unsigned int bytes)
{
if (bytes > sizeof(unsigned long long)) {
throw std::logic_error(
"QPDFWriter::writeBinary called with too many bytes");
}
unsigned char data[sizeof(unsigned long long)];
for (unsigned int i = 0; i < bytes; ++i) {
data[bytes - i - 1] = static_cast<unsigned char>(val & 0xff);
val >>= 8;
}
this->m->pipeline->write(data, bytes);
}
void
QPDFWriter::writeString(std::string const& str)
{
this->m->pipeline->write(QUtil::unsigned_char_pointer(str), str.length());
}
void
QPDFWriter::writeBuffer(std::shared_ptr<Buffer>& b)
{
this->m->pipeline->write(b->getBuffer(), b->getSize());
}
void
QPDFWriter::writeStringQDF(std::string const& str)
{
if (this->m->qdf_mode) {
writeString(str);
}
}
void
QPDFWriter::writeStringNoQDF(std::string const& str)
{
if (!this->m->qdf_mode) {
writeString(str);
}
}
void
QPDFWriter::writePad(int nspaces)
{
for (int i = 0; i < nspaces; ++i) {
writeString(" ");
}
}
Pipeline*
QPDFWriter::pushPipeline(Pipeline* p)
{
assert(dynamic_cast<Pl_Count*>(p) == 0);
this->m->pipeline_stack.push_back(p);
return p;
}
void
QPDFWriter::initializePipelineStack(Pipeline* p)
{
this->m->pipeline = new Pl_Count("pipeline stack base", p);
this->m->to_delete.push_back(std::shared_ptr<Pipeline>(this->m->pipeline));
this->m->pipeline_stack.push_back(this->m->pipeline);
}
void
QPDFWriter::activatePipelineStack(PipelinePopper& pp)
{
std::string stack_id(
"stack " + QUtil::uint_to_string(this->m->next_stack_id));
Pl_Count* c =
new Pl_Count(stack_id.c_str(), this->m->pipeline_stack.back());
++this->m->next_stack_id;
this->m->pipeline_stack.push_back(c);
this->m->pipeline = c;
pp.stack_id = stack_id;
}
QPDFWriter::PipelinePopper::~PipelinePopper()
{
if (stack_id.empty()) {
return;
}
assert(qw->m->pipeline_stack.size() >= 2);
qw->m->pipeline->finish();
assert(
dynamic_cast<Pl_Count*>(qw->m->pipeline_stack.back()) ==
qw->m->pipeline);
// It might be possible for this assertion to fail if
// writeLinearized exits by exception when deterministic ID, but I
// don't think so. As of this writing, this is the only case in
// which two dynamically allocated PipelinePopper objects ever
// exist at the same time, so the assertion will fail if they get
// popped out of order from automatic destruction.
assert(qw->m->pipeline->getIdentifier() == stack_id);
delete qw->m->pipeline_stack.back();
qw->m->pipeline_stack.pop_back();
while (dynamic_cast<Pl_Count*>(qw->m->pipeline_stack.back()) == 0) {
Pipeline* p = qw->m->pipeline_stack.back();
if (dynamic_cast<Pl_MD5*>(p) == qw->m->md5_pipeline) {
qw->m->md5_pipeline = 0;
}
qw->m->pipeline_stack.pop_back();
Pl_Buffer* buf = dynamic_cast<Pl_Buffer*>(p);
if (bp && buf) {
*bp = buf->getBufferSharedPointer();
}
delete p;
}
qw->m->pipeline = dynamic_cast<Pl_Count*>(qw->m->pipeline_stack.back());
}
void
QPDFWriter::adjustAESStreamLength(size_t& length)
{
if (this->m->encrypted && (!this->m->cur_data_key.empty()) &&
this->m->encrypt_use_aes) {
// Stream length will be padded with 1 to 16 bytes to end up
// as a multiple of 16. It will also be prepended by 16 bits
// of random data.
length += 32 - (length & 0xf);
}
}
void
QPDFWriter::pushEncryptionFilter(PipelinePopper& pp)
{
if (this->m->encrypted && (!this->m->cur_data_key.empty())) {
Pipeline* p = 0;
if (this->m->encrypt_use_aes) {
p = new Pl_AES_PDF(
"aes stream encryption",
this->m->pipeline,
true,
QUtil::unsigned_char_pointer(this->m->cur_data_key),
this->m->cur_data_key.length());
} else {
p = new Pl_RC4(
"rc4 stream encryption",
this->m->pipeline,
QUtil::unsigned_char_pointer(this->m->cur_data_key),
QIntC::to_int(this->m->cur_data_key.length()));
}
pushPipeline(p);
}
// Must call this unconditionally so we can call popPipelineStack
// to balance pushEncryptionFilter().
activatePipelineStack(pp);
}
void
QPDFWriter::pushDiscardFilter(PipelinePopper& pp)
{
pushPipeline(new Pl_Discard());
activatePipelineStack(pp);
}
void
QPDFWriter::pushMD5Pipeline(PipelinePopper& pp)
{
if (!this->m->id2.empty()) {
// Can't happen in the code
throw std::logic_error("Deterministic ID computation enabled after ID"
" generation has already occurred.");
}
assert(this->m->deterministic_id);
assert(this->m->md5_pipeline == 0);
assert(this->m->pipeline->getCount() == 0);
this->m->md5_pipeline = new Pl_MD5("qpdf md5", this->m->pipeline);
this->m->md5_pipeline->persistAcrossFinish(true);
// Special case code in popPipelineStack clears this->m->md5_pipeline
// upon deletion.
pushPipeline(this->m->md5_pipeline);
activatePipelineStack(pp);
}
void
QPDFWriter::computeDeterministicIDData()
{
assert(this->m->md5_pipeline != 0);
assert(this->m->deterministic_id_data.empty());
this->m->deterministic_id_data = this->m->md5_pipeline->getHexDigest();
this->m->md5_pipeline->enable(false);
}
int
QPDFWriter::openObject(int objid)
{
if (objid == 0) {
objid = this->m->next_objid++;
}
this->m->xref[objid] = QPDFXRefEntry(1, this->m->pipeline->getCount(), 0);
writeString(QUtil::int_to_string(objid));
writeString(" 0 obj\n");
return objid;
}
void
QPDFWriter::closeObject(int objid)
{
// Write a newline before endobj as it makes the file easier to
// repair.
writeString("\nendobj\n");
writeStringQDF("\n");
this->m->lengths[objid] =
this->m->pipeline->getCount() - this->m->xref[objid].getOffset();
}
void
QPDFWriter::assignCompressedObjectNumbers(QPDFObjGen const& og)
{
int objid = og.getObj();
if ((og.getGen() != 0) ||
(this->m->object_stream_to_objects.count(objid) == 0)) {
// This is not an object stream.
return;
}
// Reserve numbers for the objects that belong to this object
// stream.
for (auto const& iter: this->m->object_stream_to_objects[objid]) {
this->m->obj_renumber[iter] = this->m->next_objid++;
}
}
void
QPDFWriter::enqueueObject(QPDFObjectHandle object)
{
if (object.isIndirect()) {
if (object.getOwningQPDF() != &(this->m->pdf)) {
QTC::TC("qpdf", "QPDFWriter foreign object");
throw std::logic_error(
"QPDFObjectHandle from different QPDF found while writing."
" Use QPDF::copyForeignObject to add objects from"
" another file.");
}
if (this->m->qdf_mode && object.isStreamOfType("/XRef")) {
// As a special case, do not output any extraneous XRef
// streams in QDF mode. Doing so will confuse fix-qdf,
// which expects to see only one XRef stream at the end of
// the file. This case can occur when creating a QDF from
// a file with object streams when preserving unreferenced
// objects since the old cross reference streams are not
// actually referenced by object number.
QTC::TC("qpdf", "QPDFWriter ignore XRef in qdf mode");
return;
}
QPDFObjGen og = object.getObjGen();
if (this->m->obj_renumber.count(og) == 0) {
if (this->m->object_to_object_stream.count(og)) {
// This is in an object stream. Don't process it
// here. Instead, enqueue the object stream. Object
// streams always have generation 0.
int stream_id = this->m->object_to_object_stream[og];
// Detect loops by storing invalid object ID 0, which
// will get overwritten later.
this->m->obj_renumber[og] = 0;
enqueueObject(this->m->pdf.getObjectByID(stream_id, 0));
} else {
this->m->object_queue.push_back(object);
this->m->obj_renumber[og] = this->m->next_objid++;
if ((og.getGen() == 0) &&
this->m->object_stream_to_objects.count(og.getObj())) {
// For linearized files, uncompressed objects go
// at end, and we take care of assigning numbers
// to them elsewhere.
if (!this->m->linearized) {
assignCompressedObjectNumbers(og);
}
} else if (
(!this->m->direct_stream_lengths) && object.isStream()) {
// reserve next object ID for length
++this->m->next_objid;
}
}
} else if (this->m->obj_renumber[og] == 0) {
// This can happen if a specially constructed file
// indicates that an object stream is inside itself.
QTC::TC("qpdf", "QPDFWriter ignore self-referential object stream");
}
} else if (object.isArray()) {
int n = object.getArrayNItems();
for (int i = 0; i < n; ++i) {
if (!this->m->linearized) {
enqueueObject(object.getArrayItem(i));
}
}
} else if (object.isDictionary()) {
std::set<std::string> keys = object.getKeys();
for (auto const& key: keys) {
if (!this->m->linearized) {
enqueueObject(object.getKey(key));
}
}
} else {
// ignore
}
}
void
QPDFWriter::unparseChild(QPDFObjectHandle child, int level, int flags)
{
if (!this->m->linearized) {
enqueueObject(child);
}
if (child.isIndirect()) {
QPDFObjGen old_og = child.getObjGen();
int new_id = this->m->obj_renumber[old_og];
writeString(QUtil::int_to_string(new_id));
writeString(" 0 R");
} else {
unparseObject(child, level, flags);
}
}
void
QPDFWriter::writeTrailer(
trailer_e which,
int size,
bool xref_stream,
qpdf_offset_t prev,
int linearization_pass)
{
QPDFObjectHandle trailer = getTrimmedTrailer();
if (xref_stream) {
this->m->cur_data_key.clear();
} else {
writeString("trailer <<");
}
writeStringQDF("\n");
if (which == t_lin_second) {
writeString(" /Size ");
writeString(QUtil::int_to_string(size));
} else {
std::set<std::string> keys = trailer.getKeys();
for (auto const& key: keys) {
writeStringQDF(" ");
writeStringNoQDF(" ");
writeString(QPDF_Name::normalizeName(key));
writeString(" ");
if (key == "/Size") {
writeString(QUtil::int_to_string(size));
if (which == t_lin_first) {
writeString(" /Prev ");
qpdf_offset_t pos = this->m->pipeline->getCount();
writeString(QUtil::int_to_string(prev));
int nspaces =
QIntC::to_int(pos - this->m->pipeline->getCount() + 21);
if (nspaces < 0) {
throw std::logic_error(
"QPDFWriter: no padding required in trailer");
}
writePad(nspaces);
}
} else {
unparseChild(trailer.getKey(key), 1, 0);
}
writeStringQDF("\n");
}
}
// Write ID
writeStringQDF(" ");
writeString(" /ID [");
if (linearization_pass == 1) {
std::string original_id1 = getOriginalID1();
if (original_id1.empty()) {
writeString("<00000000000000000000000000000000>");
} else {
// Write a string of zeroes equal in length to the
// representation of the original ID. While writing the
// original ID would have the same number of bytes, it
// would cause a change to the deterministic ID generated
// by older versions of the software that hard-coded the
// length of the ID to 16 bytes.
writeString("<");
size_t len = QPDF_String(original_id1).unparse(true).length() - 2;
for (size_t i = 0; i < len; ++i) {
writeString("0");
}
writeString(">");
}
writeString("<00000000000000000000000000000000>");
} else {
if ((linearization_pass == 0) && (this->m->deterministic_id)) {
computeDeterministicIDData();
}
generateID();
writeString(QPDF_String(this->m->id1).unparse(true));
writeString(QPDF_String(this->m->id2).unparse(true));
}
writeString("]");
if (which != t_lin_second) {
// Write reference to encryption dictionary
if (this->m->encrypted) {
writeString(" /Encrypt ");
writeString(QUtil::int_to_string(this->m->encryption_dict_objid));
writeString(" 0 R");
}
}
writeStringQDF("\n");
writeStringNoQDF(" ");
writeString(">>");
}
bool
QPDFWriter::willFilterStream(
QPDFObjectHandle stream,
bool& compress_stream,
bool& is_metadata,
std::shared_ptr<Buffer>* stream_data)
{
compress_stream = false;
is_metadata = false;
QPDFObjGen old_og = stream.getObjGen();
QPDFObjectHandle stream_dict = stream.getDict();
if (stream_dict.isDictionaryOfType("/Metadata")) {
is_metadata = true;
}
bool filter =
(stream.isDataModified() || this->m->compress_streams ||
this->m->stream_decode_level);
bool filter_on_write = stream.getFilterOnWrite();
if (!filter_on_write) {
QTC::TC("qpdf", "QPDFWriter getFilterOnWrite false");
filter = false;
}
if (filter_on_write && this->m->compress_streams) {
// Don't filter if the stream is already compressed with
// FlateDecode. This way we don't make it worse if the
// original file used a better Flate algorithm, and we
// don't spend time and CPU cycles uncompressing and
// recompressing stuff. This can be overridden with
// setRecompressFlate(true).
QPDFObjectHandle filter_obj = stream_dict.getKey("/Filter");
if ((!this->m->recompress_flate) && (!stream.isDataModified()) &&
filter_obj.isName() &&
((filter_obj.getName() == "/FlateDecode") ||
(filter_obj.getName() == "/Fl"))) {
QTC::TC("qpdf", "QPDFWriter not recompressing /FlateDecode");
filter = false;
}
}
bool normalize = false;
bool uncompress = false;
if (filter_on_write && is_metadata &&
((!this->m->encrypted) || (this->m->encrypt_metadata == false))) {
QTC::TC("qpdf", "QPDFWriter not compressing metadata");
filter = true;
compress_stream = false;
uncompress = true;
} else if (
filter_on_write && this->m->normalize_content &&
this->m->normalized_streams.count(old_og)) {
normalize = true;
filter = true;
} else if (filter_on_write && filter && this->m->compress_streams) {
compress_stream = true;
QTC::TC("qpdf", "QPDFWriter compressing uncompressed stream");
}
bool filtered = false;
for (int attempt = 1; attempt <= 2; ++attempt) {
pushPipeline(new Pl_Buffer("stream data"));
PipelinePopper pp_stream_data(this, stream_data);
activatePipelineStack(pp_stream_data);
filtered = stream.pipeStreamData(
this->m->pipeline,
(((filter && normalize) ? qpdf_ef_normalize : 0) |
((filter && compress_stream) ? qpdf_ef_compress : 0)),
(filter ? (uncompress ? qpdf_dl_all : this->m->stream_decode_level)
: qpdf_dl_none),
false,
(attempt == 1));
if (filter && (!filtered)) {
// Try again
filter = false;
} else {
break;
}
}
if (!filtered) {
compress_stream = false;
}
return filtered;
}
void
QPDFWriter::unparseObject(
QPDFObjectHandle object,
int level,
int flags,
size_t stream_length,
bool compress)
{
QPDFObjGen old_og = object.getObjGen();
int child_flags = flags & ~f_stream;
std::string indent;
for (int i = 0; i < level; ++i) {
indent += " ";
}
if (object.isArray()) {
// Note: PDF spec 1.4 implementation note 121 states that
// Acrobat requires a space after the [ in the /H key of the
// linearization parameter dictionary. We'll do this
// unconditionally for all arrays because it looks nicer and
// doesn't make the files that much bigger.
writeString("[");
writeStringQDF("\n");
int n = object.getArrayNItems();
for (int i = 0; i < n; ++i) {
writeStringQDF(indent);
writeStringQDF(" ");
writeStringNoQDF(" ");
unparseChild(object.getArrayItem(i), level + 1, child_flags);
writeStringQDF("\n");
}
writeStringQDF(indent);
writeStringNoQDF(" ");
writeString("]");
} else if (object.isDictionary()) {
// Make a shallow copy of this object so we can modify it
// safely without affecting the original. This code has logic
// to skip certain keys in agreement with prepareFileForWrite
// and with skip_stream_parameters so that replacing them
// doesn't leave unreferenced objects in the output. We can
// use unsafeShallowCopy here because we are all we are doing
// is removing or replacing top-level keys.
object = object.unsafeShallowCopy();
// Handle special cases for specific dictionaries.
// Extensions dictionaries.
// We have one of several cases:
//
// * We need ADBE
// - We already have Extensions
// - If it has the right ADBE, preserve it
// - Otherwise, replace ADBE
// - We don't have Extensions: create one from scratch
// * We don't want ADBE
// - We already have Extensions
// - If it only has ADBE, remove it
// - If it has other things, keep those and remove ADBE
// - We have no extensions: no action required
//
// Before writing, we guarantee that /Extensions, if present,
// is direct through the ADBE dictionary, so we can modify in
// place.
bool is_root = false;
bool have_extensions_other = false;
bool have_extensions_adbe = false;
QPDFObjectHandle extensions;
if ((old_og.getObj() != 0) &&
(old_og == this->m->pdf.getRoot().getObjGen())) {
is_root = true;
if (object.hasKey("/Extensions") &&
object.getKey("/Extensions").isDictionary()) {
extensions = object.getKey("/Extensions");
}
}
if (extensions.isInitialized()) {
std::set<std::string> keys = extensions.getKeys();
if (keys.count("/ADBE") > 0) {
have_extensions_adbe = true;
keys.erase("/ADBE");
}
if (keys.size() > 0) {
have_extensions_other = true;
}
}
bool need_extensions_adbe = (this->m->final_extension_level > 0);
if (is_root) {
if (need_extensions_adbe) {
if (!(have_extensions_other || have_extensions_adbe)) {
// We need Extensions and don't have it. Create
// it here.
QTC::TC(
"qpdf",
"QPDFWriter create Extensions",
this->m->qdf_mode ? 0 : 1);
extensions = object.replaceKeyAndGet(
"/Extensions", QPDFObjectHandle::newDictionary());
}
} else if (!have_extensions_other) {
// We have Extensions dictionary and don't want one.
if (have_extensions_adbe) {
QTC::TC("qpdf", "QPDFWriter remove existing Extensions");
object.removeKey("/Extensions");
extensions = QPDFObjectHandle(); // uninitialized
}
}
}
if (extensions.isInitialized()) {
QTC::TC("qpdf", "QPDFWriter preserve Extensions");
QPDFObjectHandle adbe = extensions.getKey("/ADBE");
if (adbe.isDictionary() &&
adbe.getKey("/BaseVersion")
.isNameAndEquals("/" + this->m->final_pdf_version) &&
adbe.getKey("/ExtensionLevel").isInteger() &&
(adbe.getKey("/ExtensionLevel").getIntValue() ==
this->m->final_extension_level)) {
QTC::TC("qpdf", "QPDFWriter preserve ADBE");
} else {
if (need_extensions_adbe) {
extensions.replaceKey(
"/ADBE",
QPDFObjectHandle::parse(
"<< /BaseVersion /" + this->m->final_pdf_version +
" /ExtensionLevel " +
QUtil::int_to_string(
this->m->final_extension_level) +
" >>"));
} else {
QTC::TC("qpdf", "QPDFWriter remove ADBE");
extensions.removeKey("/ADBE");
}
}
}
// Stream dictionaries.
if (flags & f_stream) {
// Suppress /Length since we will write it manually
object.removeKey("/Length");
// If /DecodeParms is an empty list, remove it.
if (object.getKey("/DecodeParms").isArray() &&
(0 == object.getKey("/DecodeParms").getArrayNItems())) {
QTC::TC("qpdf", "QPDFWriter remove empty DecodeParms");
object.removeKey("/DecodeParms");
}
if (flags & f_filtered) {
// We will supply our own filter and decode
// parameters.
object.removeKey("/Filter");
object.removeKey("/DecodeParms");
} else {
// Make sure, no matter what else we have, that we
// don't have /Crypt in the output filters.
QPDFObjectHandle filter = object.getKey("/Filter");
QPDFObjectHandle decode_parms = object.getKey("/DecodeParms");
if (filter.isOrHasName("/Crypt")) {
if (filter.isName()) {
object.removeKey("/Filter");
object.removeKey("/DecodeParms");
} else {
int idx = -1;
for (int i = 0; i < filter.getArrayNItems(); ++i) {
QPDFObjectHandle item = filter.getArrayItem(i);
if (item.isNameAndEquals("/Crypt")) {
idx = i;
break;
}
}
if (idx >= 0) {
// If filter is an array, then the code in
// QPDF_Stream has already verified that
// DecodeParms and Filters are arrays of
// the same length, but if they weren't
// for some reason, eraseItem does type
// and bounds checking.
QTC::TC("qpdf", "QPDFWriter remove Crypt");
filter.eraseItem(idx);
decode_parms.eraseItem(idx);
}
}
}
}
}
writeString("<<");
writeStringQDF("\n");
std::set<std::string> keys = object.getKeys();
for (auto const& key: keys) {
writeStringQDF(indent);
writeStringQDF(" ");
writeStringNoQDF(" ");
writeString(QPDF_Name::normalizeName(key));
writeString(" ");
if (key == "/Contents" && object.isDictionaryOfType("/Sig") &&
object.hasKey("/ByteRange")) {
QTC::TC("qpdf", "QPDFWriter no encryption sig contents");
unparseChild(
object.getKey(key),
level + 1,
child_flags | f_hex_string | f_no_encryption);
} else {
unparseChild(object.getKey(key), level + 1, child_flags);
}
writeStringQDF("\n");
}
if (flags & f_stream) {
writeStringQDF(indent);
writeStringQDF(" ");
writeString(" /Length ");
if (this->m->direct_stream_lengths) {
writeString(QUtil::uint_to_string(stream_length));
} else {
writeString(
QUtil::int_to_string(this->m->cur_stream_length_id));
writeString(" 0 R");
}
writeStringQDF("\n");
if (compress && (flags & f_filtered)) {
writeStringQDF(indent);
writeStringQDF(" ");
writeString(" /Filter /FlateDecode");
writeStringQDF("\n");
}
}
writeStringQDF(indent);
writeStringNoQDF(" ");
writeString(">>");
} else if (object.isStream()) {
// Write stream data to a buffer.
int new_id = this->m->obj_renumber[old_og];
if (!this->m->direct_stream_lengths) {
this->m->cur_stream_length_id = new_id + 1;
}
flags |= f_stream;
bool compress_stream = false;
bool is_metadata = false;
std::shared_ptr<Buffer> stream_data;
if (willFilterStream(
object, compress_stream, is_metadata, &stream_data)) {
flags |= f_filtered;
}
QPDFObjectHandle stream_dict = object.getDict();
this->m->cur_stream_length = stream_data->getSize();
if (is_metadata && this->m->encrypted && (!this->m->encrypt_metadata)) {
// Don't encrypt stream data for the metadata stream
this->m->cur_data_key.clear();
}
adjustAESStreamLength(this->m->cur_stream_length);
unparseObject(
stream_dict, 0, flags, this->m->cur_stream_length, compress_stream);
unsigned char last_char = '\0';
writeString("\nstream\n");
{
PipelinePopper pp_enc(this);
pushEncryptionFilter(pp_enc);
writeBuffer(stream_data);
last_char = this->m->pipeline->getLastChar();
}
if (this->m->newline_before_endstream ||
(this->m->qdf_mode && (last_char != '\n'))) {
writeString("\n");
this->m->added_newline = true;
} else {
this->m->added_newline = false;
}
writeString("endstream");
} else if (object.isString()) {
std::string val;
if (this->m->encrypted && (!(flags & f_in_ostream)) &&
(!(flags & f_no_encryption)) && (!this->m->cur_data_key.empty())) {
val = object.getStringValue();
if (this->m->encrypt_use_aes) {
Pl_Buffer bufpl("encrypted string");
Pl_AES_PDF pl(
"aes encrypt string",
&bufpl,
true,
QUtil::unsigned_char_pointer(this->m->cur_data_key),
this->m->cur_data_key.length());
pl.write(QUtil::unsigned_char_pointer(val), val.length());
pl.finish();
auto buf = bufpl.getBufferSharedPointer();
val = QPDF_String(std::string(
reinterpret_cast<char*>(buf->getBuffer()),
buf->getSize()))
.unparse(true);
} else {
auto tmp_ph = QUtil::make_unique_cstr(val);
char* tmp = tmp_ph.get();
size_t vlen = val.length();
RC4 rc4(
QUtil::unsigned_char_pointer(this->m->cur_data_key),
QIntC::to_int(this->m->cur_data_key.length()));
rc4.process(QUtil::unsigned_char_pointer(tmp), vlen);
val = QPDF_String(std::string(tmp, vlen)).unparse();
}
} else if (flags & f_hex_string) {
val = QPDF_String(object.getStringValue()).unparse(true);
} else {
val = object.unparseResolved();
}
writeString(val);
} else {
writeString(object.unparseResolved());
}
}
void
QPDFWriter::writeObjectStreamOffsets(
std::vector<qpdf_offset_t>& offsets, int first_obj)
{
for (size_t i = 0; i < offsets.size(); ++i) {
if (i != 0) {
writeStringQDF("\n");
writeStringNoQDF(" ");
}
writeString(QUtil::uint_to_string(i + QIntC::to_size(first_obj)));
writeString(" ");
writeString(QUtil::int_to_string(offsets.at(i)));
}
writeString("\n");
}
void
QPDFWriter::writeObjectStream(QPDFObjectHandle object)
{
// Note: object might be null if this is a place-holder for an
// object stream that we are generating from scratch.
QPDFObjGen old_og = object.getObjGen();
assert(old_og.getGen() == 0);
int old_id = old_og.getObj();
int new_id = this->m->obj_renumber[old_og];
std::vector<qpdf_offset_t> offsets;
qpdf_offset_t first = 0;
// Generate stream itself. We have to do this in two passes so we
// can calculate offsets in the first pass.
std::shared_ptr<Buffer> stream_buffer;
int first_obj = -1;
bool compressed = false;
for (int pass = 1; pass <= 2; ++pass) {
// stream_buffer will be initialized only for pass 2
PipelinePopper pp_ostream(this, &stream_buffer);
if (pass == 1) {
pushDiscardFilter(pp_ostream);
} else {
// Adjust offsets to skip over comment before first object
first = offsets.at(0);
for (auto& iter: offsets) {
iter -= first;
}
// Take one pass at writing pairs of numbers so we can get
// their size information
{
PipelinePopper pp_discard(this);
pushDiscardFilter(pp_discard);
writeObjectStreamOffsets(offsets, first_obj);
first += this->m->pipeline->getCount();
}
// Set up a stream to write the stream data into a buffer.
Pipeline* next = pushPipeline(new Pl_Buffer("object stream"));
if ((this->m->compress_streams ||
(this->m->stream_decode_level == qpdf_dl_none)) &&
(!this->m->qdf_mode)) {
compressed = true;
next = pushPipeline(new Pl_Flate(
"compress object stream", next, Pl_Flate::a_deflate));
}
activatePipelineStack(pp_ostream);
writeObjectStreamOffsets(offsets, first_obj);
}
int count = -1;
for (auto const& obj: this->m->object_stream_to_objects[old_id]) {
++count;
int new_obj = this->m->obj_renumber[obj];
if (first_obj == -1) {
first_obj = new_obj;
}
if (this->m->qdf_mode) {
writeString(
"%% Object stream: object " +
QUtil::int_to_string(new_obj) + ", index " +
QUtil::int_to_string(count));
if (!this->m->suppress_original_object_ids) {
writeString(
"; original object ID: " +
QUtil::int_to_string(obj.getObj()));
// For compatibility, only write the generation if
// non-zero. While object streams only allow
// objects with generation 0, if we are generating
// object streams, the old object could have a
// non-zero generation.
if (obj.getGen() != 0) {
QTC::TC("qpdf", "QPDFWriter original obj non-zero gen");
writeString(" " + QUtil::int_to_string(obj.getGen()));
}
}
writeString("\n");
}
if (pass == 1) {
offsets.push_back(this->m->pipeline->getCount());
// To avoid double-counting objects being written in
// object streams for progress reporting, decrement in
// pass 1.
indicateProgress(true, false);
}
QPDFObjectHandle obj_to_write = this->m->pdf.getObjectByObjGen(obj);
if (obj_to_write.isStream()) {
// This condition occurred in a fuzz input. Ideally we
// should block it at at parse time, but it's not
// clear to me how to construct a case for this.
QTC::TC("qpdf", "QPDFWriter stream in ostream");
obj_to_write.warnIfPossible(
"stream found inside object stream; treating as null");
obj_to_write = QPDFObjectHandle::newNull();
}
writeObject(obj_to_write, count);
this->m->xref[new_obj] = QPDFXRefEntry(2, new_id, count);
}
}
// Write the object
openObject(new_id);
setDataKey(new_id);
writeString("<<");
writeStringQDF("\n ");
writeString(" /Type /ObjStm");
writeStringQDF("\n ");
size_t length = stream_buffer->getSize();
adjustAESStreamLength(length);
writeString(" /Length " + QUtil::uint_to_string(length));
writeStringQDF("\n ");
if (compressed) {
writeString(" /Filter /FlateDecode");
}
writeString(" /N " + QUtil::uint_to_string(offsets.size()));
writeStringQDF("\n ");
writeString(" /First " + QUtil::int_to_string(first));
if (!object.isNull()) {
// If the original object has an /Extends key, preserve it.
QPDFObjectHandle dict = object.getDict();
QPDFObjectHandle extends = dict.getKey("/Extends");
if (extends.isIndirect()) {
QTC::TC("qpdf", "QPDFWriter copy Extends");
writeStringQDF("\n ");
writeString(" /Extends ");
unparseChild(extends, 1, f_in_ostream);
}
}
writeStringQDF("\n");
writeStringNoQDF(" ");
writeString(">>\nstream\n");
if (this->m->encrypted) {
QTC::TC("qpdf", "QPDFWriter encrypt object stream");
}
{
PipelinePopper pp_enc(this);
pushEncryptionFilter(pp_enc);
writeBuffer(stream_buffer);
}
if (this->m->newline_before_endstream) {
writeString("\n");
}
writeString("endstream");
this->m->cur_data_key.clear();
closeObject(new_id);
}
void
QPDFWriter::writeObject(QPDFObjectHandle object, int object_stream_index)
{
QPDFObjGen old_og = object.getObjGen();
if ((object_stream_index == -1) && (old_og.getGen() == 0) &&
(this->m->object_stream_to_objects.count(old_og.getObj()))) {
writeObjectStream(object);
return;
}
indicateProgress(false, false);
int new_id = this->m->obj_renumber[old_og];
if (this->m->qdf_mode) {
if (this->m->page_object_to_seq.count(old_og)) {
writeString("%% Page ");
writeString(
QUtil::int_to_string(this->m->page_object_to_seq[old_og]));
writeString("\n");
}
if (this->m->contents_to_page_seq.count(old_og)) {
writeString("%% Contents for page ");
writeString(
QUtil::int_to_string(this->m->contents_to_page_seq[old_og]));
writeString("\n");
}
}
if (object_stream_index == -1) {
if (this->m->qdf_mode && (!this->m->suppress_original_object_ids)) {
writeString(
"%% Original object ID: " +
QUtil::int_to_string(object.getObjectID()) + " " +
QUtil::int_to_string(object.getGeneration()) + "\n");
}
openObject(new_id);
setDataKey(new_id);
unparseObject(object, 0, 0);
this->m->cur_data_key.clear();
closeObject(new_id);
} else {
unparseObject(object, 0, f_in_ostream);
writeString("\n");
}
if ((!this->m->direct_stream_lengths) && object.isStream()) {
if (this->m->qdf_mode) {
if (this->m->added_newline) {
writeString("%QDF: ignore_newline\n");
}
}
openObject(new_id + 1);
writeString(QUtil::uint_to_string(this->m->cur_stream_length));
closeObject(new_id + 1);
}
}
std::string
QPDFWriter::getOriginalID1()
{
QPDFObjectHandle trailer = this->m->pdf.getTrailer();
if (trailer.hasKey("/ID")) {
return trailer.getKey("/ID").getArrayItem(0).getStringValue();
} else {
return "";
}
}
void
QPDFWriter::generateID()
{
// Generate the ID lazily so that we can handle the user's
// preference to use static or deterministic ID generation.
if (!this->m->id2.empty()) {
return;
}
QPDFObjectHandle trailer = this->m->pdf.getTrailer();
std::string result;
if (this->m->static_id) {
// For test suite use only...
static unsigned char tmp[] = {
0x31,
0x41,
0x59,
0x26,
0x53,
0x58,
0x97,
0x93,
0x23,
0x84,
0x62,
0x64,
0x33,
0x83,
0x27,
0x95,
0x00};
result = reinterpret_cast<char*>(tmp);
} else {
// The PDF specification has guidelines for creating IDs, but
// it states clearly that the only thing that's really
// important is that it is very likely to be unique. We can't
// really follow the guidelines in the spec exactly because we
// haven't written the file yet. This scheme should be fine
// though. The deterministic ID case uses a digest of a
// sufficient portion of the file's contents such no two
// non-matching files would match in the subsets used for this
// computation. Note that we explicitly omit the filename from
// the digest calculation for deterministic ID so that the same
// file converted with qpdf, in that case, would have the same
// ID regardless of the output file's name.
std::string seed;
if (this->m->deterministic_id) {
if (this->m->deterministic_id_data.empty()) {
QTC::TC("qpdf", "QPDFWriter deterministic with no data");
throw std::logic_error(
"INTERNAL ERROR: QPDFWriter::generateID has no"
" data for deterministic ID. This may happen if"
" deterministic ID and file encryption are requested"
" together.");
}
seed += this->m->deterministic_id_data;
} else {
seed += QUtil::int_to_string(QUtil::get_current_time());
seed += this->m->filename;
seed += " ";
}
seed += " QPDF ";
if (trailer.hasKey("/Info")) {
QPDFObjectHandle info = trailer.getKey("/Info");
std::set<std::string> keys = info.getKeys();
for (auto const& key: keys) {
QPDFObjectHandle obj = info.getKey(key);
if (obj.isString()) {
seed += " ";
seed += obj.getStringValue();
}
}
}
MD5 m;
m.encodeString(seed.c_str());
MD5::Digest digest;
m.digest(digest);
result =
std::string(reinterpret_cast<char*>(digest), sizeof(MD5::Digest));
}
// If /ID already exists, follow the spec: use the original first
// word and generate a new second word. Otherwise, we'll use the
// generated ID for both.
this->m->id2 = result;
// Note: keep /ID from old file even if --static-id was given.
this->m->id1 = getOriginalID1();
if (this->m->id1.empty()) {
this->m->id1 = this->m->id2;
}
}
void
QPDFWriter::initializeSpecialStreams()
{
// Mark all page content streams in case we are filtering or
// normalizing.
std::vector<QPDFObjectHandle> pages = this->m->pdf.getAllPages();
int num = 0;
for (auto& page: pages) {
this->m->page_object_to_seq[page.getObjGen()] = ++num;
QPDFObjectHandle contents = page.getKey("/Contents");
std::vector<QPDFObjGen> contents_objects;
if (contents.isArray()) {
int n = contents.getArrayNItems();
for (int i = 0; i < n; ++i) {
contents_objects.push_back(
contents.getArrayItem(i).getObjGen());
}
} else if (contents.isStream()) {
contents_objects.push_back(contents.getObjGen());
}
for (auto const& c: contents_objects) {
this->m->contents_to_page_seq[c] = num;
this->m->normalized_streams.insert(c);
}
}
}
void
QPDFWriter::preserveObjectStreams()
{
std::map<int, int> omap;
QPDF::Writer::getObjectStreamData(this->m->pdf, omap);
if (omap.empty()) {
return;
}
// Our object_to_object_stream map has to map ObjGen -> ObjGen
// since we may be generating object streams out of old objects
// that have generation numbers greater than zero. However in an
// existing PDF, all object stream objects and all objects in them
// must have generation 0 because the PDF spec does not provide
// any way to do otherwise. This code filters out objects that are
// not allowed to be in object streams. In addition to removing
// objects that were erroneously included in object streams in the
// source PDF, it also prevents unreferenced objects from being
// included.
std::set<QPDFObjGen> eligible;
if (!this->m->preserve_unreferenced_objects) {
std::vector<QPDFObjGen> eligible_v =
QPDF::Writer::getCompressibleObjGens(this->m->pdf);
eligible = std::set<QPDFObjGen>(eligible_v.begin(), eligible_v.end());
}
QTC::TC(
"qpdf",
"QPDFWriter preserve object streams",
this->m->preserve_unreferenced_objects ? 0 : 1);
for (auto iter: omap) {
QPDFObjGen og(iter.first, 0);
if (eligible.count(og) || this->m->preserve_unreferenced_objects) {
this->m->object_to_object_stream[og] = iter.second;
} else {
QTC::TC("qpdf", "QPDFWriter exclude from object stream");
}
}
}
void
QPDFWriter::generateObjectStreams()
{
// Basic strategy: make a list of objects that can go into an
// object stream. Then figure out how many object streams are
// needed so that we can distribute objects approximately evenly
// without having any object stream exceed 100 members. We don't
// have to worry about linearized files here -- if the file is
// linearized, we take care of excluding things that aren't
// allowed here later.
// This code doesn't do anything with /Extends.
std::vector<QPDFObjGen> eligible =
QPDF::Writer::getCompressibleObjGens(this->m->pdf);
size_t n_object_streams = (eligible.size() + 99U) / 100U;
if (n_object_streams == 0) {
return;
}
size_t n_per = eligible.size() / n_object_streams;
if (n_per * n_object_streams < eligible.size()) {
++n_per;
}
unsigned int n = 0;
int cur_ostream = 0;
for (auto const& iter: eligible) {
if ((n % n_per) == 0) {
if (n > 0) {
QTC::TC("qpdf", "QPDFWriter generate >1 ostream");
}
n = 0;
}
if (n == 0) {
// Construct a new null object as the "original" object
// stream. The rest of the code knows that this means
// we're creating the object stream from scratch.
cur_ostream =
this->m->pdf.makeIndirectObject(QPDFObjectHandle::newNull())
.getObjectID();
}
this->m->object_to_object_stream[iter] = cur_ostream;
++n;
}
}
QPDFObjectHandle
QPDFWriter::getTrimmedTrailer()
{
// Remove keys from the trailer that necessarily have to be
// replaced when writing the file.
QPDFObjectHandle trailer = this->m->pdf.getTrailer().unsafeShallowCopy();
// Remove encryption keys
trailer.removeKey("/ID");
trailer.removeKey("/Encrypt");
// Remove modification information
trailer.removeKey("/Prev");
// Remove all trailer keys that potentially come from a
// cross-reference stream
trailer.removeKey("/Index");
trailer.removeKey("/W");
trailer.removeKey("/Length");
trailer.removeKey("/Filter");
trailer.removeKey("/DecodeParms");
trailer.removeKey("/Type");
trailer.removeKey("/XRefStm");
return trailer;
}
void
QPDFWriter::prepareFileForWrite()
{
// Make document extension level information direct as required by
// the spec.
this->m->pdf.fixDanglingReferences(true);
QPDFObjectHandle root = this->m->pdf.getRoot();
for (auto const& key: root.getKeys()) {
QPDFObjectHandle oh = root.getKey(key);
if ((key == "/Extensions") && (oh.isDictionary())) {
bool extensions_indirect = false;
if (oh.isIndirect()) {
QTC::TC("qpdf", "QPDFWriter make Extensions direct");
extensions_indirect = true;
oh = root.replaceKeyAndGet(key, oh.shallowCopy());
}
if (oh.hasKey("/ADBE")) {
QPDFObjectHandle adbe = oh.getKey("/ADBE");
if (adbe.isIndirect()) {
QTC::TC(
"qpdf",
"QPDFWriter make ADBE direct",
extensions_indirect ? 0 : 1);
adbe.makeDirect();
oh.replaceKey("/ADBE", adbe);
}
}
}
}
}
void
QPDFWriter::doWriteSetup()
{
if (this->m->did_write_setup) {
return;
}
this->m->did_write_setup = true;
// Do preliminary setup
if (this->m->linearized) {
this->m->qdf_mode = false;
}
if (this->m->pclm) {
this->m->stream_decode_level = qpdf_dl_none;
this->m->compress_streams = false;
this->m->encrypted = false;
}
if (this->m->qdf_mode) {
if (!this->m->normalize_content_set) {
this->m->normalize_content = true;
}
if (!this->m->compress_streams_set) {
this->m->compress_streams = false;
}
if (!this->m->stream_decode_level_set) {
this->m->stream_decode_level = qpdf_dl_generalized;
}
}
if (this->m->encrypted) {
// Encryption has been explicitly set
this->m->preserve_encryption = false;
} else if (
this->m->normalize_content || this->m->stream_decode_level ||
this->m->pclm || this->m->qdf_mode) {
// Encryption makes looking at contents pretty useless. If
// the user explicitly encrypted though, we still obey that.
this->m->preserve_encryption = false;
}
if (this->m->preserve_encryption) {
copyEncryptionParameters(this->m->pdf);
}
if (!this->m->forced_pdf_version.empty()) {
int major = 0;
int minor = 0;
parseVersion(this->m->forced_pdf_version, major, minor);
disableIncompatibleEncryption(
major, minor, this->m->forced_extension_level);
if (compareVersions(major, minor, 1, 5) < 0) {
QTC::TC("qpdf", "QPDFWriter forcing object stream disable");
this->m->object_stream_mode = qpdf_o_disable;
}
}
if (this->m->qdf_mode || this->m->normalize_content ||
this->m->stream_decode_level) {
initializeSpecialStreams();
}
if (this->m->qdf_mode) {
// Generate indirect stream lengths for qdf mode since fix-qdf
// uses them for storing recomputed stream length data.
// Certain streams such as object streams, xref streams, and
// hint streams always get direct stream lengths.
this->m->direct_stream_lengths = false;
}
switch (this->m->object_stream_mode) {
case qpdf_o_disable:
// no action required
break;
case qpdf_o_preserve:
preserveObjectStreams();
break;
case qpdf_o_generate:
generateObjectStreams();
break;
// no default so gcc will warn for missing case tag
}
if (this->m->linearized) {
// Page dictionaries are not allowed to be compressed objects.
std::vector<QPDFObjectHandle> pages = this->m->pdf.getAllPages();
for (auto& page: pages) {
QPDFObjGen og = page.getObjGen();
if (this->m->object_to_object_stream.count(og)) {
QTC::TC("qpdf", "QPDFWriter uncompressing page dictionary");
this->m->object_to_object_stream.erase(og);
}
}
}
if (this->m->linearized || this->m->encrypted) {
// The document catalog is not allowed to be compressed in
// linearized files either. It also appears that Adobe Reader
// 8.0.0 has a bug that prevents it from being able to handle
// encrypted files with compressed document catalogs, so we
// disable them in that case as well.
QPDFObjGen og = this->m->pdf.getRoot().getObjGen();
if (this->m->object_to_object_stream.count(og)) {
QTC::TC("qpdf", "QPDFWriter uncompressing root");
this->m->object_to_object_stream.erase(og);
}
}
// Generate reverse mapping from object stream to objects
for (auto const& iter: this->m->object_to_object_stream) {
QPDFObjGen const& obj = iter.first;
int stream = iter.second;
this->m->object_stream_to_objects[stream].insert(obj);
this->m->max_ostream_index = std::max(
this->m->max_ostream_index,
QIntC::to_int(this->m->object_stream_to_objects[stream].size()) -
1);
}
if (!this->m->object_stream_to_objects.empty()) {
setMinimumPDFVersion("1.5");
}
setMinimumPDFVersion(
this->m->pdf.getPDFVersion(), this->m->pdf.getExtensionLevel());
this->m->final_pdf_version = this->m->min_pdf_version;
this->m->final_extension_level = this->m->min_extension_level;
if (!this->m->forced_pdf_version.empty()) {
QTC::TC("qpdf", "QPDFWriter using forced PDF version");
this->m->final_pdf_version = this->m->forced_pdf_version;
this->m->final_extension_level = this->m->forced_extension_level;
}
}
void
QPDFWriter::write()
{
doWriteSetup();
// Set up progress reporting. For linearized files, we write two
// passes. events_expected is an approximation, but it's good
// enough for progress reporting, which is mostly a guess anyway.
this->m->events_expected = QIntC::to_int(
this->m->pdf.getObjectCount() * (this->m->linearized ? 2 : 1));
prepareFileForWrite();
if (this->m->linearized) {
writeLinearized();
} else {
writeStandard();
}
this->m->pipeline->finish();
if (this->m->close_file) {
fclose(this->m->file);
}
this->m->file = 0;
if (this->m->buffer_pipeline) {
this->m->output_buffer = this->m->buffer_pipeline->getBuffer();
this->m->buffer_pipeline = 0;
}
indicateProgress(false, true);
}
QPDFObjGen
QPDFWriter::getRenumberedObjGen(QPDFObjGen og)
{
return QPDFObjGen(this->m->obj_renumber[og], 0);
}
std::map<QPDFObjGen, QPDFXRefEntry>
QPDFWriter::getWrittenXRefTable()
{
std::map<QPDFObjGen, QPDFXRefEntry> result;
for (auto const& iter: this->m->xref) {
if (iter.first != 0 && iter.second.getType() != 0) {
result[QPDFObjGen(iter.first, 0)] = iter.second;
}
}
return result;
}
void
QPDFWriter::enqueuePart(std::vector<QPDFObjectHandle>& part)
{
for (auto const& oh: part) {
enqueueObject(oh);
}
}
void
QPDFWriter::writeEncryptionDictionary()
{
this->m->encryption_dict_objid = openObject(this->m->encryption_dict_objid);
writeString("<<");
for (auto const& iter: this->m->encryption_dictionary) {
writeString(" ");
writeString(iter.first);
writeString(" ");
writeString(iter.second);
}
writeString(" >>");
closeObject(this->m->encryption_dict_objid);
}
std::string
QPDFWriter::getFinalVersion()
{
doWriteSetup();
return this->m->final_pdf_version;
}
void
QPDFWriter::writeHeader()
{
writeString("%PDF-");
writeString(this->m->final_pdf_version);
if (this->m->pclm) {
// PCLm version
writeString("\n%PCLm 1.0\n");
} else {
// This string of binary characters would not be valid UTF-8, so
// it really should be treated as binary.
writeString("\n%\xbf\xf7\xa2\xfe\n");
}
writeStringQDF("%QDF-1.0\n\n");
// Note: do not write extra header text here. Linearized PDFs
// must include the entire linearization parameter dictionary
// within the first 1024 characters of the PDF file, so for
// linearized files, we have to write extra header text after the
// linearization parameter dictionary.
}
void
QPDFWriter::writeHintStream(int hint_id)
{
std::shared_ptr<Buffer> hint_buffer;
int S = 0;
int O = 0;
QPDF::Writer::generateHintStream(
this->m->pdf,
this->m->xref,
this->m->lengths,
this->m->obj_renumber_no_gen,
hint_buffer,
S,
O);
openObject(hint_id);
setDataKey(hint_id);
size_t hlen = hint_buffer->getSize();
writeString("<< /Filter /FlateDecode /S ");
writeString(QUtil::int_to_string(S));
if (O) {
writeString(" /O ");
writeString(QUtil::int_to_string(O));
}
writeString(" /Length ");
adjustAESStreamLength(hlen);
writeString(QUtil::uint_to_string(hlen));
writeString(" >>\nstream\n");
if (this->m->encrypted) {
QTC::TC("qpdf", "QPDFWriter encrypted hint stream");
}
unsigned char last_char = '\0';
{
PipelinePopper pp_enc(this);
pushEncryptionFilter(pp_enc);
writeBuffer(hint_buffer);
last_char = this->m->pipeline->getLastChar();
}
if (last_char != '\n') {
writeString("\n");
}
writeString("endstream");
closeObject(hint_id);
}
qpdf_offset_t
QPDFWriter::writeXRefTable(trailer_e which, int first, int last, int size)
{
// There are too many extra arguments to replace overloaded
// function with defaults in the header file...too much risk of
// leaving something off.
return writeXRefTable(which, first, last, size, 0, false, 0, 0, 0, 0);
}
qpdf_offset_t
QPDFWriter::writeXRefTable(
trailer_e which,
int first,
int last,
int size,
qpdf_offset_t prev,
bool suppress_offsets,
int hint_id,
qpdf_offset_t hint_offset,
qpdf_offset_t hint_length,
int linearization_pass)
{
writeString("xref\n");
writeString(QUtil::int_to_string(first));
writeString(" ");
writeString(QUtil::int_to_string(last - first + 1));
qpdf_offset_t space_before_zero = this->m->pipeline->getCount();
writeString("\n");
for (int i = first; i <= last; ++i) {
if (i == 0) {
writeString("0000000000 65535 f \n");
} else {
qpdf_offset_t offset = 0;
if (!suppress_offsets) {
offset = this->m->xref[i].getOffset();
if ((hint_id != 0) && (i != hint_id) &&
(offset >= hint_offset)) {
offset += hint_length;
}
}
writeString(QUtil::int_to_string(offset, 10));
writeString(" 00000 n \n");
}
}
writeTrailer(which, size, false, prev, linearization_pass);
writeString("\n");
return space_before_zero;
}
qpdf_offset_t
QPDFWriter::writeXRefStream(
int objid,
int max_id,
qpdf_offset_t max_offset,
trailer_e which,
int first,
int last,
int size)
{
// There are too many extra arguments to replace overloaded
// function with defaults in the header file...too much risk of
// leaving something off.
return writeXRefStream(
objid,
max_id,
max_offset,
which,
first,
last,
size,
0,
0,
0,
0,
false,
0);
}
qpdf_offset_t
QPDFWriter::writeXRefStream(
int xref_id,
int max_id,
qpdf_offset_t max_offset,
trailer_e which,
int first,
int last,
int size,
qpdf_offset_t prev,
int hint_id,
qpdf_offset_t hint_offset,
qpdf_offset_t hint_length,
bool skip_compression,
int linearization_pass)
{
qpdf_offset_t xref_offset = this->m->pipeline->getCount();
qpdf_offset_t space_before_zero = xref_offset - 1;
// field 1 contains offsets and object stream identifiers
unsigned int f1_size =
std::max(bytesNeeded(max_offset + hint_length), bytesNeeded(max_id));
// field 2 contains object stream indices
unsigned int f2_size = bytesNeeded(this->m->max_ostream_index);
unsigned int esize = 1 + f1_size + f2_size;
// Must store in xref table in advance of writing the actual data
// rather than waiting for openObject to do it.
this->m->xref[xref_id] = QPDFXRefEntry(1, this->m->pipeline->getCount(), 0);
Pipeline* p = pushPipeline(new Pl_Buffer("xref stream"));
bool compressed = false;
if ((this->m->compress_streams ||
(this->m->stream_decode_level == qpdf_dl_none)) &&
(!this->m->qdf_mode)) {
compressed = true;
if (!skip_compression) {
// Write the stream dictionary for compression but don't
// actually compress. This helps us with computation of
// padding for pass 1 of linearization.
p = pushPipeline(
new Pl_Flate("compress xref", p, Pl_Flate::a_deflate));
}
p = pushPipeline(
new Pl_PNGFilter("pngify xref", p, Pl_PNGFilter::a_encode, esize));
}
std::shared_ptr<Buffer> xref_data;
{
PipelinePopper pp_xref(this, &xref_data);
activatePipelineStack(pp_xref);
for (int i = first; i <= last; ++i) {
QPDFXRefEntry& e = this->m->xref[i];
switch (e.getType()) {
case 0:
writeBinary(0, 1);
writeBinary(0, f1_size);
writeBinary(0, f2_size);
break;
case 1:
{
qpdf_offset_t offset = e.getOffset();
if ((hint_id != 0) && (i != hint_id) &&
(offset >= hint_offset)) {
offset += hint_length;
}
writeBinary(1, 1);
writeBinary(QIntC::to_ulonglong(offset), f1_size);
writeBinary(0, f2_size);
}
break;
case 2:
writeBinary(2, 1);
writeBinary(
QIntC::to_ulonglong(e.getObjStreamNumber()), f1_size);
writeBinary(
QIntC::to_ulonglong(e.getObjStreamIndex()), f2_size);
break;
default:
throw std::logic_error("invalid type writing xref stream");
break;
}
}
}
openObject(xref_id);
writeString("<<");
writeStringQDF("\n ");
writeString(" /Type /XRef");
writeStringQDF("\n ");
writeString(" /Length " + QUtil::uint_to_string(xref_data->getSize()));
if (compressed) {
writeStringQDF("\n ");
writeString(" /Filter /FlateDecode");
writeStringQDF("\n ");
writeString(
" /DecodeParms << /Columns " + QUtil::int_to_string(esize) +
" /Predictor 12 >>");
}
writeStringQDF("\n ");
writeString(
" /W [ 1 " + QUtil::int_to_string(f1_size) + " " +
QUtil::int_to_string(f2_size) + " ]");
if (!((first == 0) && (last == size - 1))) {
writeString(
" /Index [ " + QUtil::int_to_string(first) + " " +
QUtil::int_to_string(last - first + 1) + " ]");
}
writeTrailer(which, size, true, prev, linearization_pass);
writeString("\nstream\n");
writeBuffer(xref_data);
writeString("\nendstream");
closeObject(xref_id);
return space_before_zero;
}
int
QPDFWriter::calculateXrefStreamPadding(qpdf_offset_t xref_bytes)
{
// This routine is called right after a linearization first pass
// xref stream has been written without compression. Calculate
// the amount of padding that would be required in the worst case,
// assuming the number of uncompressed bytes remains the same.
// The worst case for zlib is that the output is larger than the
// input by 6 bytes plus 5 bytes per 16K, and then we'll add 10
// extra bytes for number length increases.
return QIntC::to_int(16 + (5 * ((xref_bytes + 16383) / 16384)));
}
void
QPDFWriter::discardGeneration(
std::map<QPDFObjGen, int> const& in, std::map<int, int>& out)
{
// There are deep assumptions in the linearization code in QPDF
// that there is only one object with each object number; i.e.,
// you can't have two objects with the same object number and
// different generations. This is a pretty safe assumption
// because Adobe Reader and Acrobat can't actually handle this
// case. There is not much if any code in QPDF outside
// linearization that assumes this, but the linearization code as
// currently implemented would do weird things if we found such a
// case. In order to avoid breaking ABI changes in QPDF, we will
// first assert that this condition holds. Then we can create new
// maps for QPDF that throw away generation numbers.
out.clear();
for (auto const& iter: in) {
if (out.count(iter.first.getObj())) {
throw std::runtime_error(
"QPDF cannot currently linearize files that contain"
" multiple objects with the same object ID and different"
" generations. If you see this error message, please file"
" a bug report and attach the file if possible. As a"
" workaround, first convert the file with qpdf without"
" linearizing, and then linearize the result of that"
" conversion.");
}
out[iter.first.getObj()] = iter.second;
}
}
void
QPDFWriter::writeLinearized()
{
// Optimize file and enqueue objects in order
discardGeneration(
this->m->object_to_object_stream,
this->m->object_to_object_stream_no_gen);
auto skip_stream_parameters = [this](QPDFObjectHandle& stream) {
bool compress_stream;
bool is_metadata;
if (willFilterStream(stream, compress_stream, is_metadata, nullptr)) {
return 2;
} else {
return 1;
}
};
this->m->pdf.optimize(
this->m->object_to_object_stream_no_gen, true, skip_stream_parameters);
std::vector<QPDFObjectHandle> part4;
std::vector<QPDFObjectHandle> part6;
std::vector<QPDFObjectHandle> part7;
std::vector<QPDFObjectHandle> part8;
std::vector<QPDFObjectHandle> part9;
QPDF::Writer::getLinearizedParts(
this->m->pdf,
this->m->object_to_object_stream_no_gen,
part4,
part6,
part7,
part8,
part9);
// Object number sequence:
//
// second half
// second half uncompressed objects
// second half xref stream, if any
// second half compressed objects
// first half
// linearization dictionary
// first half xref stream, if any
// part 4 uncompresesd objects
// encryption dictionary, if any
// hint stream
// part 6 uncompressed objects
// first half compressed objects
//
// Second half objects
int second_half_uncompressed =
QIntC::to_int(part7.size() + part8.size() + part9.size());
int second_half_first_obj = 1;
int after_second_half = 1 + second_half_uncompressed;
this->m->next_objid = after_second_half;
int second_half_xref = 0;
bool need_xref_stream = (!this->m->object_to_object_stream.empty());
if (need_xref_stream) {
second_half_xref = this->m->next_objid++;
}
// Assign numbers to all compressed objects in the second half.
std::vector<QPDFObjectHandle>* vecs2[] = {&part7, &part8, &part9};
for (int i = 0; i < 3; ++i) {
for (auto const& oh: *vecs2[i]) {
assignCompressedObjectNumbers(oh.getObjGen());
}
}
int second_half_end = this->m->next_objid - 1;
int second_trailer_size = this->m->next_objid;
// First half objects
int first_half_start = this->m->next_objid;
int lindict_id = this->m->next_objid++;
int first_half_xref = 0;
if (need_xref_stream) {
first_half_xref = this->m->next_objid++;
}
int part4_first_obj = this->m->next_objid;
this->m->next_objid += QIntC::to_int(part4.size());
int after_part4 = this->m->next_objid;
if (this->m->encrypted) {
this->m->encryption_dict_objid = this->m->next_objid++;
}
int hint_id = this->m->next_objid++;
int part6_first_obj = this->m->next_objid;
this->m->next_objid += QIntC::to_int(part6.size());
int after_part6 = this->m->next_objid;
// Assign numbers to all compressed objects in the first half
std::vector<QPDFObjectHandle>* vecs1[] = {&part4, &part6};
for (int i = 0; i < 2; ++i) {
for (auto const& oh: *vecs1[i]) {
assignCompressedObjectNumbers(oh.getObjGen());
}
}
int first_half_end = this->m->next_objid - 1;
int first_trailer_size = this->m->next_objid;
int part4_end_marker = part4.back().getObjectID();
int part6_end_marker = part6.back().getObjectID();
qpdf_offset_t space_before_zero = 0;
qpdf_offset_t file_size = 0;
qpdf_offset_t part6_end_offset = 0;
qpdf_offset_t first_half_max_obj_offset = 0;
qpdf_offset_t second_xref_offset = 0;
qpdf_offset_t first_xref_end = 0;
qpdf_offset_t second_xref_end = 0;
this->m->next_objid = part4_first_obj;
enqueuePart(part4);
if (this->m->next_objid != after_part4) {
// This can happen with very botched files as in the fuzzer
// test. There are likely some faulty assumptions in
// calculateLinearizationData
throw std::runtime_error("error encountered after"
" writing part 4 of linearized data");
}
this->m->next_objid = part6_first_obj;
enqueuePart(part6);
if (this->m->next_objid != after_part6) {
throw std::runtime_error("error encountered after"
" writing part 6 of linearized data");
}
this->m->next_objid = second_half_first_obj;
enqueuePart(part7);
enqueuePart(part8);
enqueuePart(part9);
if (this->m->next_objid != after_second_half) {
throw std::runtime_error("error encountered after"
" writing part 9 of linearized data");
}
qpdf_offset_t hint_length = 0;
std::shared_ptr<Buffer> hint_buffer;
// Write file in two passes. Part numbers refer to PDF spec 1.4.
FILE* lin_pass1_file = 0;
auto pp_pass1 = std::make_shared<PipelinePopper>(this);
auto pp_md5 = std::make_shared<PipelinePopper>(this);
for (int pass = 1; pass <= 2; ++pass) {
if (pass == 1) {
if (!this->m->lin_pass1_filename.empty()) {
lin_pass1_file = QUtil::safe_fopen(
this->m->lin_pass1_filename.c_str(), "wb");
pushPipeline(
new Pl_StdioFile("linearization pass1", lin_pass1_file));
activatePipelineStack(*pp_pass1);
} else {
pushDiscardFilter(*pp_pass1);
}
if (this->m->deterministic_id) {
pushMD5Pipeline(*pp_md5);
}
}
// Part 1: header
writeHeader();
// Part 2: linearization parameter dictionary. Save enough
// space to write real dictionary. 200 characters is enough
// space if all numerical values in the parameter dictionary
// that contain offsets are 20 digits long plus a few extra
// characters for safety. The entire linearization parameter
// dictionary must appear within the first 1024 characters of
// the file.
qpdf_offset_t pos = this->m->pipeline->getCount();
openObject(lindict_id);
writeString("<<");
if (pass == 2) {
std::vector<QPDFObjectHandle> const& pages =
this->m->pdf.getAllPages();
int first_page_object =
this->m->obj_renumber[pages.at(0).getObjGen()];
int npages = QIntC::to_int(pages.size());
writeString(" /Linearized 1 /L ");
writeString(QUtil::int_to_string(file_size + hint_length));
// Implementation note 121 states that a space is
// mandatory after this open bracket.
writeString(" /H [ ");
writeString(
QUtil::int_to_string(this->m->xref[hint_id].getOffset()));
writeString(" ");
writeString(QUtil::int_to_string(hint_length));
writeString(" ] /O ");
writeString(QUtil::int_to_string(first_page_object));
writeString(" /E ");
writeString(QUtil::int_to_string(part6_end_offset + hint_length));
writeString(" /N ");
writeString(QUtil::int_to_string(npages));
writeString(" /T ");
writeString(QUtil::int_to_string(space_before_zero + hint_length));
}
writeString(" >>");
closeObject(lindict_id);
static int const pad = 200;
int spaces = QIntC::to_int(pos - this->m->pipeline->getCount() + pad);
assert(spaces >= 0);
writePad(spaces);
writeString("\n");
// If the user supplied any additional header text, write it
// here after the linearization parameter dictionary.
writeString(this->m->extra_header_text);
// Part 3: first page cross reference table and trailer.
qpdf_offset_t first_xref_offset = this->m->pipeline->getCount();
qpdf_offset_t hint_offset = 0;
if (pass == 2) {
hint_offset = this->m->xref[hint_id].getOffset();
}
if (need_xref_stream) {
// Must pad here too.
if (pass == 1) {
// Set first_half_max_obj_offset to a value large
// enough to force four bytes to be reserved for each
// file offset. This would provide adequate space for
// the xref stream as long as the last object in page
// 1 starts with in the first 4 GB of the file, which
// is extremely likely. In the second pass, we will
// know the actual value for this, but it's okay if
// it's smaller.
first_half_max_obj_offset = 1 << 25;
}
pos = this->m->pipeline->getCount();
writeXRefStream(
first_half_xref,
first_half_end,
first_half_max_obj_offset,
t_lin_first,
first_half_start,
first_half_end,
first_trailer_size,
hint_length + second_xref_offset,
hint_id,
hint_offset,
hint_length,
(pass == 1),
pass);
qpdf_offset_t endpos = this->m->pipeline->getCount();
if (pass == 1) {
// Pad so we have enough room for the real xref
// stream.
writePad(calculateXrefStreamPadding(endpos - pos));
first_xref_end = this->m->pipeline->getCount();
} else {
// Pad so that the next object starts at the same
// place as in pass 1.
writePad(QIntC::to_int(first_xref_end - endpos));
if (this->m->pipeline->getCount() != first_xref_end) {
throw std::logic_error(
"insufficient padding for first pass xref stream; "
"first_xref_end=" +
QUtil::int_to_string(first_xref_end) +
"; endpos=" + QUtil::int_to_string(endpos));
}
}
writeString("\n");
} else {
writeXRefTable(
t_lin_first,
first_half_start,
first_half_end,
first_trailer_size,
hint_length + second_xref_offset,
(pass == 1),
hint_id,
hint_offset,
hint_length,
pass);
writeString("startxref\n0\n%%EOF\n");
}
// Parts 4 through 9
for (auto const& cur_object: this->m->object_queue) {
if (cur_object.getObjectID() == part6_end_marker) {
first_half_max_obj_offset = this->m->pipeline->getCount();
}
writeObject(cur_object);
if (cur_object.getObjectID() == part4_end_marker) {
if (this->m->encrypted) {
writeEncryptionDictionary();
}
if (pass == 1) {
this->m->xref[hint_id] =
QPDFXRefEntry(1, this->m->pipeline->getCount(), 0);
} else {
// Part 5: hint stream
writeBuffer(hint_buffer);
}
}
if (cur_object.getObjectID() == part6_end_marker) {
part6_end_offset = this->m->pipeline->getCount();
}
}
// Part 10: overflow hint stream -- not used
// Part 11: main cross reference table and trailer
second_xref_offset = this->m->pipeline->getCount();
if (need_xref_stream) {
pos = this->m->pipeline->getCount();
space_before_zero = writeXRefStream(
second_half_xref,
second_half_end,
second_xref_offset,
t_lin_second,
0,
second_half_end,
second_trailer_size,
0,
0,
0,
0,
(pass == 1),
pass);
qpdf_offset_t endpos = this->m->pipeline->getCount();
if (pass == 1) {
// Pad so we have enough room for the real xref
// stream. See comments for previous xref stream on
// how we calculate the padding.
writePad(calculateXrefStreamPadding(endpos - pos));
writeString("\n");
second_xref_end = this->m->pipeline->getCount();
} else {
// Make the file size the same.
writePad(QIntC::to_int(
second_xref_end + hint_length - 1 -
this->m->pipeline->getCount()));
writeString("\n");
// If this assertion fails, maybe we didn't have
// enough padding above.
if (this->m->pipeline->getCount() !=
second_xref_end + hint_length) {
throw std::logic_error("count mismatch after xref stream;"
" possible insufficient padding?");
}
}
} else {
space_before_zero = writeXRefTable(
t_lin_second,
0,
second_half_end,
second_trailer_size,
0,
false,
0,
0,
0,
pass);
}
writeString("startxref\n");
writeString(QUtil::int_to_string(first_xref_offset));
writeString("\n%%EOF\n");
discardGeneration(this->m->obj_renumber, this->m->obj_renumber_no_gen);
if (pass == 1) {
if (this->m->deterministic_id) {
QTC::TC(
"qpdf",
"QPDFWriter linearized deterministic ID",
need_xref_stream ? 0 : 1);
computeDeterministicIDData();
pp_md5 = 0;
assert(this->m->md5_pipeline == 0);
}
// Close first pass pipeline
file_size = this->m->pipeline->getCount();
pp_pass1 = 0;
// Save hint offset since it will be set to zero by
// calling openObject.
qpdf_offset_t hint_offset1 = this->m->xref[hint_id].getOffset();
// Write hint stream to a buffer
{
pushPipeline(new Pl_Buffer("hint buffer"));
PipelinePopper pp_hint(this, &hint_buffer);
activatePipelineStack(pp_hint);
writeHintStream(hint_id);
}
hint_length = QIntC::to_offset(hint_buffer->getSize());
// Restore hint offset
this->m->xref[hint_id] = QPDFXRefEntry(1, hint_offset1, 0);
if (lin_pass1_file) {
// Write some debugging information
fprintf(
lin_pass1_file,
"%% hint_offset=%s\n",
QUtil::int_to_string(hint_offset1).c_str());
fprintf(
lin_pass1_file,
"%% hint_length=%s\n",
QUtil::int_to_string(hint_length).c_str());
fprintf(
lin_pass1_file,
"%% second_xref_offset=%s\n",
QUtil::int_to_string(second_xref_offset).c_str());
fprintf(
lin_pass1_file,
"%% second_xref_end=%s\n",
QUtil::int_to_string(second_xref_end).c_str());
fclose(lin_pass1_file);
lin_pass1_file = 0;
}
}
}
}
void
QPDFWriter::enqueueObjectsStandard()
{
if (this->m->preserve_unreferenced_objects) {
QTC::TC("qpdf", "QPDFWriter preserve unreferenced standard");
for (auto const& oh: this->m->pdf.getAllObjects()) {
enqueueObject(oh);
}
}
// Put root first on queue.
QPDFObjectHandle trailer = getTrimmedTrailer();
enqueueObject(trailer.getKey("/Root"));
// Next place any other objects referenced from the trailer
// dictionary into the queue, handling direct objects recursively.
// Root is already there, so enqueuing it a second time is a
// no-op.
std::set<std::string> keys = trailer.getKeys();
for (auto const& key: keys) {
enqueueObject(trailer.getKey(key));
}
}
void
QPDFWriter::enqueueObjectsPCLm()
{
// Image transform stream content for page strip images.
// Each of this new stream has to come after every page image
// strip written in the pclm file.
std::string image_transform_content = "q /image Do Q\n";
// enqueue all pages first
std::vector<QPDFObjectHandle> all = this->m->pdf.getAllPages();
for (auto& page: all) {
// enqueue page
enqueueObject(page);
// enqueue page contents stream
enqueueObject(page.getKey("/Contents"));
// enqueue all the strips for each page
QPDFObjectHandle strips = page.getKey("/Resources").getKey("/XObject");
std::set<std::string> keys = strips.getKeys();
for (auto const& image: keys) {
enqueueObject(strips.getKey(image));
enqueueObject(QPDFObjectHandle::newStream(
&this->m->pdf, image_transform_content));
}
}
// Put root in queue.
QPDFObjectHandle trailer = getTrimmedTrailer();
enqueueObject(trailer.getKey("/Root"));
}
void
QPDFWriter::indicateProgress(bool decrement, bool finished)
{
if (decrement) {
--this->m->events_seen;
return;
}
++this->m->events_seen;
if (!this->m->progress_reporter.get()) {
return;
}
if (finished || (this->m->events_seen >= this->m->next_progress_report)) {
int percentage =
(finished ? 100
: this->m->next_progress_report == 0
? 0
: std::min(
99,
1 +
((100 * this->m->events_seen) /
this->m->events_expected)));
this->m->progress_reporter->reportProgress(percentage);
}
int increment = std::max(1, (this->m->events_expected / 100));
while (this->m->events_seen >= this->m->next_progress_report) {
this->m->next_progress_report += increment;
}
}
void
QPDFWriter::registerProgressReporter(std::shared_ptr<ProgressReporter> pr)
{
this->m->progress_reporter = pr;
}
void
QPDFWriter::writeStandard()
{
auto pp_md5 = std::make_shared<PipelinePopper>(this);
if (this->m->deterministic_id) {
pushMD5Pipeline(*pp_md5);
}
// Start writing
writeHeader();
writeString(this->m->extra_header_text);
if (this->m->pclm) {
enqueueObjectsPCLm();
} else {
enqueueObjectsStandard();
}
// Now start walking queue, outputting each object.
while (this->m->object_queue.size()) {
QPDFObjectHandle cur_object = this->m->object_queue.front();
this->m->object_queue.pop_front();
writeObject(cur_object);
}
// Write out the encryption dictionary, if any
if (this->m->encrypted) {
writeEncryptionDictionary();
}
// Now write out xref. next_objid is now the number of objects.
qpdf_offset_t xref_offset = this->m->pipeline->getCount();
if (this->m->object_stream_to_objects.empty()) {
// Write regular cross-reference table
writeXRefTable(
t_normal, 0, this->m->next_objid - 1, this->m->next_objid);
} else {
// Write cross-reference stream.
int xref_id = this->m->next_objid++;
writeXRefStream(
xref_id,
xref_id,
xref_offset,
t_normal,
0,
this->m->next_objid - 1,
this->m->next_objid);
}
writeString("startxref\n");
writeString(QUtil::int_to_string(xref_offset));
writeString("\n%%EOF\n");
if (this->m->deterministic_id) {
QTC::TC(
"qpdf",
"QPDFWriter standard deterministic ID",
this->m->object_stream_to_objects.empty() ? 0 : 1);
pp_md5 = 0;
assert(this->m->md5_pipeline == 0);
}
}
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