Fix bug in merging resources /DR from foreign AcroForm (fixes #548)

When making resources indirect in from_dr, the code was using the
wrong owning QPDF, forgetting that from_dr had already been copied
using CopyForeignObject.

ChangeLog

@@ -1,5 +1,8 @@
 2021-11-04  Jay Berkenbilt  <ejb@ql.org>
 
+	* Bug fix: fix crash that could occur under certain conditions
+	when using --pages with files that had form fields. Fixes #548.
+
 	* Add an extra check to the library to detect when foreign objects
 	are inserted directly (instead of using
 	<function>QPDF::copyForeignObject</function>) at the time of

fuzz/build.mk

@@ -41,6 +41,7 @@ CORPUS_FROM_TEST = \
 	outlines-with-old-root-dests.pdf \
 	page-labels-and-outlines.pdf \
 	page-labels-num-tree.pdf \
+	dr-with-indirect-item.pdf \
 	fuzz-16214.pdf \
 	issue-99b.pdf \
 	issue-99.pdf \

fuzz/qtest/fuzz.test

@@ -9,7 +9,7 @@ require TestDriver;
 
 my $td = new TestDriver('fuzz');
 
-my $qpdf_n_test_files = 30;
+my $qpdf_n_test_files = 31;
 my @extra = glob("../qpdf_extra/*.fuzz");
 my $qpdf_n_extra_files = scalar(@extra);
 my $qpdf_n_orig_files = 2557;

libqpdf/QPDFAcroFormDocumentHelper.cc

@@ -1002,8 +1002,10 @@ QPDFAcroFormDocumentHelper::transformAnnotations(
             }
             // Merge the other document's /DR, creating a conflict
             // map. mergeResources checks to make sure both objects
-            // are dictionaries.
+            // are dictionaries. By this point, if this is foreign,
-            from_dr.makeResourcesIndirect(*from_qpdf);
+            // from_dr has been copied, so we use the target qpdf as
+            // the owning qpdf.
+            from_dr.makeResourcesIndirect(this->qpdf);
             dr.mergeResources(from_dr, &dr_map);
 
             if (from_afdh->getNeedAppearances())

manual/qpdf-manual.xml

@@ -5086,6 +5086,13 @@ print "\n";
           (with no resource dictionary).
          </para>
         </listitem>
+        <listitem>
+         <para>
+          Fix crash that could occur under certain conditions when
+          using <option>--pages</option> with files that had form
+          fields.
+         </para>
+        </listitem>
        </itemizedlist>
       </listitem>
       <listitem>

qpdf/qtest/qpdf.test

@@ -1025,7 +1025,7 @@ my @bug_tests = (
     ["335a", "ozz-fuzz-12152", 2],
     ["335b", "ozz-fuzz-14845", 2],
     ["fuzz-16214", "stream in object stream", 3, "--preserve-unreferenced"],
-    # When adding to this list, consider adding to SEED_CORPUS_FILES
+    # When adding to this list, consider adding to CORPUS_FROM_TEST
     # in fuzz/build.mk and updating the count in fuzz/qtest/fuzz.test.
     );
 $n_tests += scalar(@bug_tests);
@@ -3517,7 +3517,7 @@ for (my $n = 16; $n <= 19; ++$n)
 show_ntests();
 # ----------
 $td->notify("--- Specific File Tests ---");
-$n_tests += 9;
+$n_tests += 11;
 
 # Special PDF files that caused problems at some point
 
@@ -3556,6 +3556,15 @@ $td->runtest("pages points to page",
 $td->runtest("check output",
 	     {$td->FILE => "a.pdf"},
 	     {$td->FILE => "pages-is-page-out.pdf"});
+$td->runtest("Acroform /DR with indirect subkey",
+             {$td->COMMAND =>
+                  "qpdf --static-id --empty" .
+                  " --pages dr-with-indirect-item.pdf -- a.pdf"},
+             {$td->STRING => "", $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "dr-with-indirect-item-out.pdf"});
 
 show_ntests();
 # ----------

qpdf/qtest/qpdf/dr-with-indirect-item-out.pdf

@@ -0,0 +1,37 @@
+%PDF-1.3
+%¿÷¢þ
+1 0 obj
+<< /AcroForm 2 0 R /Pages 3 0 R /Type /Catalog >>
+endobj
+2 0 obj
+<< /DR 4 0 R /Fields [ 5 0 R ] >>
+endobj
+3 0 obj
+<< /Count 1 /Kids [ 6 0 R ] /Type /Pages >>
+endobj
+4 0 obj
+<< /Font << /F 7 0 R >> >>
+endobj
+5 0 obj
+<< /DA (0 0 0 rg /Helv 11 Tf) /DV () /F 4 /FT /Tx /P 6 0 R /Rect [ 0 0 1 1 ] /Subtype /Widget /T () /TU () /Type /Annot /V () >>
+endobj
+6 0 obj
+<< /Annots [ 5 0 R ] /MediaBox [ 0 0 1 1 ] /Parent 3 0 R /Resources << /Font << >> >> /Type /Page >>
+endobj
+7 0 obj
+<< >>
+endobj
+xref
+0 8
+0000000000 65535 f 
+0000000015 00000 n 
+0000000080 00000 n 
+0000000129 00000 n 
+0000000188 00000 n 
+0000000230 00000 n 
+0000000374 00000 n 
+0000000490 00000 n 
+trailer << /Root 1 0 R /Size 8 /ID [<31415926535897932384626433832795><31415926535897932384626433832795>] >>
+startxref
+511
+%%EOF

qpdf/qtest/qpdf/dr-with-indirect-item.pdf

@@ -0,0 +1,33 @@
+%PDF-1.4
+%¿÷¢þ
+1 0 obj
+<< /AcroForm << /DR 2 0 R /Fields [ 3 0 R ] >> /Pages 4 0 R /Type /Catalog >>
+endobj
+2 0 obj
+<< /Font 5 0 R >>
+endobj
+3 0 obj
+<< /DA (0 0 0 rg /Helv 11 Tf) /DV () /F 4 /FT /Tx /P 6 0 R /Rect [ 0 0 1 1 ] /Subtype /Widget /T () /TU () /Type /Annot /V () >>
+endobj
+4 0 obj
+<< /Count 1 /Kids [ 6 0 R ] /MediaBox [ 0 0 1 1 ] /Resources 2 0 R /Type /Pages >>
+endobj
+5 0 obj
+<< /F << >> >>
+endobj
+6 0 obj
+<< /Annots [ 3 0 R ] /MediaBox [ 0 0 1 1 ] /Parent 4 0 R /Resources 2 0 R /Type /Page >>
+endobj
+xref
+0 7
+0000000000 65535 f 
+0000000015 00000 n 
+0000000108 00000 n 
+0000000141 00000 n 
+0000000285 00000 n 
+0000000383 00000 n 
+0000000413 00000 n 
+trailer << /Root 1 0 R /Size 7 /ID [<5e0a553555622a0516e9877ca55217a6><f50ce4731cef7b31118d5f69b0bed95c>] >>
+startxref
+517
+%%EOF