Warn for duplicated dictionary keys (fixes #345)

Jay Berkenbilt
1 parent 5ce287d6
Showing 8 changed files with 27 additions and 2 deletions
ChangeLog
libqpdf/QPDFObjectHandle.cc
qpdf/qpdf.testcov
qpdf/qtest/qpdf.test
qpdf/qtest/qpdf/bad17-recover.out
qpdf/qtest/qpdf/bad17.out
qpdf/qtest/qpdf/bad17.pdf
qpdf/qtest/qpdf/issue-51.out
+2019-09-19  Jay Berkenbilt  <ejb@ql.org>
+
+	* Warn when duplicated dictionary keys are found during parsing.
+	The behavior remains as before: later keys override earlier ones.
+	However, this generates a warning now rather than being silently
+	ignored. Fixes #345.
+
 2019-09-17  Jay Berkenbilt  <ejb@ql.org>
 	* QIntC tests: don't assume char is signed. Fixes #361.
@@ -2135,7 +2135,18 @@ QPDFObjectHandle::parseInternal(PointerHolder&lt;InputSource&gt; input,
                     {
                         val = olist.at(++i);
                     }
-                    dict[key_obj.getName()] = val;
+                    std::string key = key_obj.getName();
+                    if (dict.count(key) > 0)
+                    {
+                        QTC::TC("qpdf", "QPDFObjectHandle duplicate dict key");
+                        warn(context,
+                             QPDFExc(
+                                 qpdf_e_damaged_pdf,
+                                 input->getName(), object_description, offset,
+                                 "dictionary has duplicated key " + key +
+                                 "; last occurrence overrides earlier ones"));
+                    }
+                    dict[key] = val;
                 }
                 object = newDictionary(dict);
                 setObjectDescriptionFromInput(
@@ -445,3 +445,4 @@ QPDF eof skipping spaces before xref 1
 QPDF_encryption user matches owner V < 5 0
 QPDF_encryption same password 1
 QPDFWriter stream in ostream 0
+QPDFObjectHandle duplicate dict key 0
@@ -2314,7 +2314,7 @@ my @badfiles = (&quot;not a PDF file&quot;, 			# 1
 		"bad }",				# 14
 		"bad ]",				# 15
 		"bad >>",				# 16
-		"odd number of dictionary items",	# 17
+		"dictionary errors",                    # 17
 		"bad )",				# 18
 		"bad >",				# 19
 		"invalid hexstring character",		# 20
+WARNING: bad17.pdf (trailer, offset 715): dictionary has duplicated key /K; last occurrence overrides earlier ones
 WARNING: bad17.pdf (trailer, offset 715): dictionary ended prematurely; using null as value for last key
 /QTest is implicit
 /QTest is direct and has type null (2)
+WARNING: bad17.pdf (trailer, offset 715): dictionary has duplicated key /K; last occurrence overrides earlier ones
 WARNING: bad17.pdf (trailer, offset 715): dictionary ended prematurely; using null as value for last key
 /QTest is implicit
 /QTest is direct and has type null (2)
@@ -73,6 +73,8 @@ xref
 trailer <<
   /Size 7
   /Root 1 0 R
+  /K 1
+  /K 2
   /Something
 >>
 startxref
 WARNING: issue-51.pdf: can't find PDF header
 WARNING: issue-51.pdf: reported number of objects (0) is not one plus the highest object number (8)
+WARNING: issue-51.pdf (object 7 0, offset 476): dictionary has duplicated key /0000; last occurrence overrides earlier ones
 WARNING: issue-51.pdf (object 7 0, offset 553): expected endobj
+WARNING: issue-51.pdf (object 1 0, offset 236): dictionary has duplicated key /00000000; last occurrence overrides earlier ones
 WARNING: issue-51.pdf (object 1 0, offset 359): expected endobj
 WARNING: issue-51.pdf (offset 70): loop detected resolving object 2 0
 WARNING: issue-51.pdf (object 2 0, offset 26): /Length key in stream dictionary is not an integer