bug fix: more gracefully handle xref stream with too many entries

git-svn-id: svn+q:///qpdf/trunk@747 71b93d88-0707-0410-a8cf-f5a4172ac649

ChangeLog

@@ -1,3 +1,9 @@
+2009-10-04  Jay Berkenbilt  <ejb@ql.org>
+
+	* libqpdf/QPDF.cc (processXRefStream): warn and ignore extra xref
+	stream entries when stream is larger than reported size.  This
+	used to be a fatal error.  (Fixes qpdf-Bugs-2872265.)
+
 2009-09-27  Jay Berkenbilt  <ejb@ql.org>
 
 	* Add several methods to query permissions controlled by the

libqpdf/QPDF.cc

@@ -787,10 +787,18 @@ QPDF::processXRefStream(off_t xref_offset, QPDFObjectHandle& xref_obj)
 
     if (expected_size != actual_size)
     {
-	throw QPDFExc(this->file.getName(), xref_offset,
-		      "Cross-reference stream data has the wrong size;"
-		      " expected = " + QUtil::int_to_string(expected_size) +
-		      "; actual = " + QUtil::int_to_string(actual_size));
+	QPDFExc x(this->file.getName(), xref_offset,
+		  "Cross-reference stream data has the wrong size;"
+		  " expected = " + QUtil::int_to_string(expected_size) +
+		  "; actual = " + QUtil::int_to_string(actual_size));
+	if (expected_size > actual_size)
+	{
+	    throw x;
+	}
+	else
+	{
+	    warn(x);
+	}
     }
 
     int cur_chunk = 0;

qpdf/qtest/qpdf.test

@@ -81,7 +81,7 @@ flush_tiff_cache();
 show_ntests();
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 4;
+$n_tests += 7;
 
 foreach (my $i = 1; $i <= 3; ++$i)
 {
@@ -98,6 +98,23 @@ $td->runtest("unknown decode parameters",
 	      $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
 
+# Handle xref stream with more entries than reported (bug 2872265)
+$td->runtest("xref with short size",
+	     {$td->COMMAND => "qpdf --show-xref xref-with-short-size.pdf"},
+	     {$td->FILE => "xref-with-short-size.out",
+	      $td->EXIT_STATUS => 3},
+	     $td->NORMALIZE_NEWLINES);
+$td->runtest("recover xref with short size",
+	     {$td->COMMAND => "qpdf xref-with-short-size.pdf a.pdf"},
+	     {$td->FILE => "xref-with-short-size-recover.out",
+	      $td->EXIT_STATUS => 3},
+	     $td->NORMALIZE_NEWLINES);
+$td->runtest("show new xref stream",
+	     {$td->COMMAND => "qpdf --show-xref a.pdf"},
+	     {$td->FILE => "xref-with-short-size-new.out",
+	      $td->EXIT_STATUS => 0},
+	     $td->NORMALIZE_NEWLINES);
+
 show_ntests();
 # ----------
 $td->notify("--- Error Condition Tests ---");

qpdf/qtest/qpdf/xref-with-short-size-new.out

@@ -0,0 +1,13 @@
+1/0: uncompressed; offset = 15
+2/0: compressed; stream = 1, index = 0
+3/0: compressed; stream = 1, index = 1
+4/0: compressed; stream = 1, index = 2
+5/0: compressed; stream = 1, index = 3
+6/0: compressed; stream = 1, index = 4
+7/0: compressed; stream = 1, index = 5
+8/0: compressed; stream = 1, index = 6
+9/0: compressed; stream = 1, index = 7
+10/0: compressed; stream = 1, index = 8
+11/0: uncompressed; offset = 674
+12/0: uncompressed; offset = 801
+13/0: uncompressed; offset = 16194

qpdf/qtest/qpdf/xref-with-short-size-recover.out

@@ -0,0 +1,2 @@
+WARNING: xref-with-short-size.pdf: offset 16227: Cross-reference stream data has the wrong size; expected = 52; actual = 56
+qpdf: operation succeeded with warnings; resulting file may have some problems

qpdf/qtest/qpdf/xref-with-short-size.out

@@ -0,0 +1,14 @@
+WARNING: xref-with-short-size.pdf: offset 16227: Cross-reference stream data has the wrong size; expected = 52; actual = 56
+1/0: compressed; stream = 5, index = 1
+2/0: compressed; stream = 5, index = 0
+3/0: uncompressed; offset = 15
+4/0: compressed; stream = 5, index = 5
+5/0: uncompressed; offset = 15548
+6/0: compressed; stream = 5, index = 6
+7/0: compressed; stream = 5, index = 4
+8/0: compressed; stream = 5, index = 2
+9/0: uncompressed; offset = 150
+10/0: compressed; stream = 5, index = 3
+11/0: compressed; stream = 5, index = 7
+12/0: compressed; stream = 5, index = 8
+qpdf: operation succeeded with warnings; resulting file may have some problems