Add new integer accessors to QPDFObjectHandle

ChangeLog

@@ -1,5 +1,9 @@
 2019-06-20  Jay Berkenbilt  <ejb@ql.org>
 
+	* Add methods to QPDFObjectHandle to return the value of Integer
+	objects as int and unsigned int with range checking and fallback
+	behavior to avoid silent underflow/overflow conditions.
+
 	* Add functions to QUtil to convert unsigned integers to strings,
 	avoiding implicit conversion between unsigned and signed integer
 	types.

include/qpdf/QPDFObjectHandle.hh

@@ -491,6 +491,12 @@ class QPDFObjectHandle
     // Methods for integer objects
     QPDF_DLL
     long long getIntValue();
+    QPDF_DLL
+    int getIntValueAsInt();
+    QPDF_DLL
+    unsigned long long getUIntValue();
+    QPDF_DLL
+    unsigned int getUIntValueAsUInt();
 
     // Methods for real objects
     QPDF_DLL

libqpdf/QPDFObjectHandle.cc

@@ -26,6 +26,7 @@
 #include <stdexcept>
 #include <stdlib.h>
 #include <ctype.h>
+#include <limits.h>
 
 class TerminateParsing
 {
@@ -406,6 +407,82 @@ QPDFObjectHandle::getIntValue()
     }
 }
 
+int
+QPDFObjectHandle::getIntValueAsInt()
+{
+    int result = 0;
+    long long v = getIntValue();
+    if (v < INT_MIN)
+    {
+        QTC::TC("qpdf", "QPDFObjectHandle int returning INT_MIN");
+        warnIfPossible(
+            "requested value of integer is too small; returning INT_MIN",
+            false);
+        result = INT_MIN;
+    }
+    else if (v > INT_MAX)
+    {
+        QTC::TC("qpdf", "QPDFObjectHandle int returning INT_MAX");
+        warnIfPossible(
+            "requested value of integer is too big; returning INT_MAX",
+            false);
+        result = INT_MAX;
+    }
+    else
+    {
+        result = static_cast<int>(v);
+    }
+    return result;
+}
+
+unsigned long long
+QPDFObjectHandle::getUIntValue()
+{
+    unsigned long long result = 0;
+    long long v = getIntValue();
+    if (v < 0)
+    {
+        QTC::TC("qpdf", "QPDFObjectHandle uint returning 0");
+        warnIfPossible(
+            "unsigned value request for negative number; returning 0",
+            false);
+    }
+    else
+    {
+        result = static_cast<unsigned long long>(v);
+    }
+    return result;
+}
+
+unsigned int
+QPDFObjectHandle::getUIntValueAsUInt()
+{
+    unsigned int result = 0;
+    long long v = getIntValue();
+    if (v < 0)
+    {
+        QTC::TC("qpdf", "QPDFObjectHandle uint uint returning 0");
+        warnIfPossible(
+            "unsigned integer value request for negative number; returning 0",
+            false);
+        result = 0;
+    }
+    else if (v > UINT_MAX)
+    {
+        QTC::TC("qpdf", "QPDFObjectHandle uint returning UINT_MAX");
+        warnIfPossible(
+            "requested value of unsigned integer is too big;"
+            " returning UINT_MAX",
+            false);
+        result = UINT_MAX;
+    }
+    else
+    {
+        result = static_cast<unsigned int>(v);
+    }
+    return result;
+}
+
 // Real accessors
 
 std::string

qpdf/qpdf.testcov

@@ -440,3 +440,8 @@ QPDFPageObjectHelper keep inline image 0
 qpdf image optimize colorspace 0
 qpdf image optimize bits per component 0
 QPDFWriter remove empty DecodeParms 0
+QPDFObjectHandle uint returning 0 0
+QPDFObjectHandle int returning INT_MIN 0
+QPDFObjectHandle int returning INT_MAX 0
+QPDFObjectHandle uint returning UINT_MAX 0
+QPDFObjectHandle uint uint returning 0 0

qpdf/qtest/qpdf.test

@@ -2286,7 +2286,7 @@ my @badfiles = ("not a PDF file", 			# 1
                 "bad dictionary key",                   # 36
 		);
 
-$n_tests += @badfiles + 5;
+$n_tests += @badfiles + 6;
 
 # Test 6 contains errors in the free table consistency, but we no
 # longer have any consistency check for this since it is not important
@@ -2334,6 +2334,11 @@ $td->runtest("C API: no recovery",
 	      $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
 
+$td->runtest("integer type checks",
+             {$td->COMMAND => "test_driver 62 minimal.pdf"},
+             {$td->STRING => "test 62 done\n", $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+
 show_ntests();
 # ----------
 $td->notify("--- Recovery Tests ---");

qpdf/test_driver.cc

@@ -24,6 +24,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <assert.h>
+#include <limits.h>
 #include <map>
 
 static char const* whoami = 0;
@@ -189,21 +190,35 @@ static void read_file_into_memory(
             throw std::runtime_error(
                 std::string("failure reading file ") + filename +
                 " into memory: read " +
-                QUtil::int_to_string(bytes_read) + "; wanted " +
+                QUtil::uint_to_string(bytes_read) + "; wanted " +
-                QUtil::int_to_string(size));
+                QUtil::uint_to_string(size));
         }
         else
         {
             throw std::logic_error(
                 std::string("premature eof reading file ") + filename +
                 " into memory: read " +
-                QUtil::int_to_string(bytes_read) + "; wanted " +
+                QUtil::uint_to_string(bytes_read) + "; wanted " +
-                QUtil::int_to_string(size));
+                QUtil::uint_to_string(size));
         }
     }
     fclose(f);
 }
 
+#define assert_compare_numbers(expected, expr) \
+    compare_numbers(#expr, expected, expr)
+
+template <typename T1, typename T2>
+static void compare_numbers(
+    char const* description, T1 const& expected, T2 const& actual)
+{
+    if (expected != actual)
+    {
+        std::cerr << description << ": expected = " << expected
+                  << "; actual = " << actual << std::endl;
+    }
+}
+
 void runtest(int n, char const* filename1, char const* arg2)
 {
     // Most tests here are crafted to work on specific files.  Look at
@@ -2090,6 +2105,31 @@ void runtest(int n, char const* filename1, char const* arg2)
             std::cout << "Caught runtime_error as expected" << std::endl;
         }
     }
+    else if (n == 62)
+    {
+        // Test int size checks. This test will fail if int and long
+        // long are the same size.
+        QPDFObjectHandle t = pdf.getTrailer();
+        unsigned long long q1_l = 3L * INT_MAX;
+        long long q1 = static_cast<long long>(q1_l);
+        long long q2_l = 3L * INT_MIN;
+        long long q2 = static_cast<long long>(q2_l);
+        unsigned int q3_i = UINT_MAX;
+        long long q3 = static_cast<long long>(q3_i);
+        t.replaceKey("/Q1", QPDFObjectHandle::newInteger(q1));
+        t.replaceKey("/Q2", QPDFObjectHandle::newInteger(q2));
+        t.replaceKey("/Q3", QPDFObjectHandle::newInteger(q3));
+        assert_compare_numbers(q1, t.getKey("/Q1").getIntValue());
+        assert_compare_numbers(q1_l, t.getKey("/Q1").getUIntValue());
+        assert_compare_numbers(INT_MAX, t.getKey("/Q1").getIntValueAsInt());
+        assert_compare_numbers(UINT_MAX, t.getKey("/Q1").getUIntValueAsUInt());
+        assert_compare_numbers(q2_l, t.getKey("/Q2").getIntValue());
+        assert_compare_numbers(0U, t.getKey("/Q2").getUIntValue());
+        assert_compare_numbers(INT_MIN, t.getKey("/Q2").getIntValueAsInt());
+        assert_compare_numbers(0U, t.getKey("/Q2").getUIntValueAsUInt());
+        assert_compare_numbers(INT_MAX, t.getKey("/Q3").getIntValueAsInt());
+        assert_compare_numbers(UINT_MAX, t.getKey("/Q3").getUIntValueAsUInt());
+    }
     else
     {
 	throw std::runtime_error(std::string("invalid test ") +