add C API for R4 encryption

git-svn-id: svn+q:///qpdf/trunk@825 71b93d88-0707-0410-a8cf-f5a4172ac649

include/qpdf/QPDFWriter.hh

@@ -110,6 +110,11 @@ class DLL_EXPORT QPDFWriter
     // suites.
     void setStaticID(bool);
 
+    // Use a fixed initialization vector for AES-CBC encryption.  This
+    // is not secure.  It should be used only in test suites for
+    // creating predictable encrypted output.
+    void setStaticAesIV(bool);
+
     // Suppress inclusion of comments indicating original object IDs
     // when writing QDF files.  This can also be useful for testing,
     // particularly when using comparison of two qdf files to

include/qpdf/qpdf-c.h

@@ -226,6 +226,12 @@ extern "C" {
     DLL_EXPORT
     void qpdf_set_static_ID(qpdf_data qpdf, QPDF_BOOL value);
 
+    /* Never use qpdf_set_static_aes_IV except in test suites to
+     * create predictable AES encrypted output.
+     */
+    DLL_EXPORT
+    void qpdf_set_static_aes_IV(qpdf_data qpdf, QPDF_BOOL value);
+
     DLL_EXPORT
     void qpdf_set_suppress_original_object_IDs(
 	qpdf_data qpdf, QPDF_BOOL value);
@@ -258,6 +264,13 @@ extern "C" {
 	QPDF_BOOL allow_accessibility, QPDF_BOOL allow_extract,
 	int print, int modify);
 
+    DLL_EXPORT
+    void qpdf_set_r4_encryption_parameters(
+	qpdf_data qpdf, char const* user_password, char const* owner_password,
+	QPDF_BOOL allow_accessibility, QPDF_BOOL allow_extract,
+	int print, int modify,
+	QPDF_BOOL encrypt_metadata, QPDF_BOOL use_aes);
+
     DLL_EXPORT
     void qpdf_set_linearization(qpdf_data qpdf, QPDF_BOOL value);
 

libqpdf/Pl_AES_PDF.cc

@@ -12,6 +12,8 @@
 # define srandom srand
 #endif
 
+bool Pl_AES_PDF::use_static_iv = false;
+
 Pl_AES_PDF::Pl_AES_PDF(char const* identifier, Pipeline* next,
 		       bool encrypt, unsigned char const key[key_size]) :
     Pipeline(identifier, next),
@@ -51,6 +53,12 @@ Pl_AES_PDF::disableCBC()
     this->cbc_mode = false;
 }
 
+void
+Pl_AES_PDF::useStaticIV()
+{
+    use_static_iv = true;
+}
+
 void
 Pl_AES_PDF::write(unsigned char* data, int len)
 {
@@ -116,9 +124,19 @@ Pl_AES_PDF::initializeVector()
 	srandom((int)QUtil::get_current_time() ^ 0xcccc);
 	seeded_random = true;
     }
-    for (unsigned int i = 0; i < this->buf_size; ++i)
+    if (use_static_iv)
     {
-	this->cbc_block[i] = (unsigned char)((random() & 0xff0) >> 4);
+	for (unsigned int i = 0; i < this->buf_size; ++i)
+	{
+	    this->cbc_block[i] = 14 * (1 + i);
+	}
+    }
+    else
+    {
+	for (unsigned int i = 0; i < this->buf_size; ++i)
+	{
+	    this->cbc_block[i] = (unsigned char)((random() & 0xff0) >> 4);
+	}
     }
 }
 

libqpdf/QPDFWriter.cc

@@ -139,6 +139,15 @@ QPDFWriter::setStaticID(bool val)
     this->static_id = val;
 }
 
+void
+QPDFWriter::setStaticAesIV(bool val)
+{
+    if (val)
+    {
+	Pl_AES_PDF::useStaticIV();
+    }
+}
+
 void
 QPDFWriter::setSuppressOriginalObjectIDs(bool val)
 {

libqpdf/qpdf-c.cc

@@ -313,6 +313,12 @@ void qpdf_set_static_ID(qpdf_data qpdf, QPDF_BOOL value)
     qpdf->qpdf_writer->setStaticID(value);
 }
 
+void qpdf_set_static_aes_IV(qpdf_data qpdf, QPDF_BOOL value)
+{
+    QTC::TC("qpdf", "qpdf-c called qpdf_set_static_aes_IV");
+    qpdf->qpdf_writer->setStaticAesIV(value);
+}
+
 void qpdf_set_suppress_original_object_IDs(
     qpdf_data qpdf, QPDF_BOOL value)
 {
@@ -356,6 +362,26 @@ void qpdf_set_r3_encryption_parameters(
 	 QPDFWriter::r3m_all));
 }
 
+void qpdf_set_r4_encryption_parameters(
+    qpdf_data qpdf, char const* user_password, char const* owner_password,
+    QPDF_BOOL allow_accessibility, QPDF_BOOL allow_extract,
+    int print, int modify, QPDF_BOOL encrypt_metadata, QPDF_BOOL use_aes)
+{
+    QTC::TC("qpdf", "qpdf-c called qpdf_set_r4_encryption_parameters");
+    qpdf->qpdf_writer->setR4EncryptionParameters(
+	user_password, owner_password,
+	allow_accessibility, allow_extract,
+	((print == QPDF_R3_PRINT_LOW) ? QPDFWriter::r3p_low :
+	 (print == QPDF_R3_PRINT_NONE) ? QPDFWriter::r3p_none :
+	 QPDFWriter::r3p_full),
+	((modify == QPDF_R3_MODIFY_ANNOTATE) ? QPDFWriter::r3m_annotate :
+	 (modify == QPDF_R3_MODIFY_FORM) ? QPDFWriter::r3m_form :
+	 (modify == QPDF_R3_MODIFY_ASSEMBLY) ? QPDFWriter::r3m_assembly :
+	 (modify == QPDF_R3_MODIFY_NONE) ? QPDFWriter::r3m_none :
+	 QPDFWriter::r3m_all),
+	encrypt_metadata, use_aes);
+}
+
 void qpdf_set_linearization(qpdf_data qpdf, QPDF_BOOL value)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_set_linearization");

libqpdf/qpdf/Pl_AES_PDF.hh

@@ -20,12 +20,15 @@ class DLL_EXPORT Pl_AES_PDF: public Pipeline
 
     // For testing only; PDF always uses CBC
     void disableCBC();
+    // For testing only: use a fixed initialization vector for CBC
+    static void useStaticIV();
 
   private:
     void flush(bool discard_padding);
     void initializeVector();
 
     static unsigned int const buf_size = 16;
+    static bool use_static_iv;
 
     bool encrypt;
     bool cbc_mode;

qpdf/qpdf-ctest.c

@@ -229,6 +229,22 @@ static void test14(char const* infile,
     report_errors();
 }
 
+static void test15(char const* infile,
+		   char const* password,
+		   char const* outfile,
+		   char const* outfile2)
+{
+    qpdf_read(qpdf, infile, password);
+    qpdf_init_write(qpdf, outfile);
+    qpdf_set_static_ID(qpdf, QPDF_TRUE);
+    qpdf_set_static_aes_IV(qpdf, QPDF_TRUE);
+    qpdf_set_r4_encryption_parameters(
+	qpdf, "user2", "owner2", QPDF_TRUE, QPDF_TRUE,
+	QPDF_R3_PRINT_LOW, QPDF_R3_MODIFY_ALL, QPDF_TRUE, QPDF_TRUE);
+    qpdf_write(qpdf);
+    report_errors();
+}
+
 int main(int argc, char* argv[])
 {
     char* whoami = 0;
@@ -278,6 +294,7 @@ int main(int argc, char* argv[])
 	  (n == 12) ? test12 :
 	  (n == 13) ? test13 :
 	  (n == 14) ? test14 :
+	  (n == 15) ? test15 :
 	  0);
 
     if (fn == 0)

qpdf/qpdf.cc

@@ -146,6 +146,8 @@ These options can be useful for digging into PDF files or for use in\n\
 automated test suites for software that uses the qpdf library.\n\
 \n\
 --static-id               generate static /ID: FOR TESTING ONLY!\n\
+--static-aes-iv           use a static initialization vector for AES-CBC\n\
+                          This is option is not secure!  FOR TESTING ONLY!\n\
 --no-original-object-ids  suppress original object ID comments in qdf mode\n\
 --show-encryption         quickly show encryption parameters\n\
 --check-linearization     check file integrity and linearization status\n\
@@ -604,6 +606,7 @@ int main(int argc, char* argv[])
     std::string force_version;
 
     bool static_id = false;
+    bool static_aes_iv = false;
     bool suppress_original_object_id = false;
     bool show_encryption = false;
     bool check_linearization = false;
@@ -758,6 +761,10 @@ int main(int argc, char* argv[])
 	    {
 		static_id = true;
 	    }
+	    else if (strcmp(arg, "static-aes-iv") == 0)
+	    {
+		static_aes_iv = true;
+	    }
 	    else if (strcmp(arg, "no-original-object-ids") == 0)
 	    {
 		suppress_original_object_id = true;
@@ -1049,6 +1056,10 @@ int main(int argc, char* argv[])
 	    {
 		w.setStaticID(true);
 	    }
+	    if (static_aes_iv)
+	    {
+		w.setStaticAesIV(true);
+	    }
 	    if (suppress_original_object_id)
 	    {
 		w.setSuppressOriginalObjectIDs(true);

qpdf/qpdf.testcov

@@ -168,3 +168,5 @@ QPDF_encryption cleartext metadata 0
 QPDF_encryption aes decode stream 0
 QPDFWriter forcing object stream disable 0
 QPDFWriter forced version disabled encryption 0
+qpdf-c called qpdf_set_r4_encryption_parameters 0
+qpdf-c called qpdf_set_static_aes_IV 0

qpdf/qtest/qpdf.test

@@ -954,6 +954,7 @@ $td->runtest("invalid password",
 my @cenc = (
     [11, 'hybrid-xref.pdf', "''", 'r2', ""],
     [12, 'hybrid-xref.pdf', "''", 'r3', ""],
+    [15, 'hybrid-xref.pdf', "''", 'r4', ""],
     [13, 'c-r2.pdf', 'user1', 'decrypt with user',
      "user password: user1\n"],
     [13, 'c-r3.pdf', 'owner2', 'decrypt with owner',