fix: use vector::at() rather than operator[] (backport #1735) (#1741)

* fix: use vector::at() rather than operator[] (#1735)

* Regression test for https://github.com/Exiv2/exiv2/issues/1706

* Use vector::at() rather than operator[].

* Print to stderr when exception is caught and EXIV2_DEBUG_MESSAGES is enabled.

* Check that it prints "Bad value" for the date.

(cherry picked from commit f4d3adbf91e6dc4e34aee5bac7b7fd9e127a5c00)

# Conflicts:
#	src/value.cpp

* fix merge conflicts from mergify backport

Co-authored-by: Kevin Backhouse <kevinbackhouse@github.com>
Co-authored-by: Christoph Hasse <hassec@users.noreply.github.com>

include/exiv2/value.hpp

@@ -1616,7 +1616,7 @@ namespace Exiv2 {
     std::string ValueType<T>::toString(long n) const
     {
         ok_ = true;
-        return Exiv2::toString<T>(value_[n]);
+        return Exiv2::toString<T>(value_.at(n));
     }
 
     // Default implementation
@@ -1624,69 +1624,69 @@ namespace Exiv2 {
     long ValueType<T>::toLong(long n) const
     {
         ok_ = true;
-        return static_cast<long>(value_[n]);
+        return static_cast<long>(value_.at(n));
     }
-// #55 crash when value_[n].first == LONG_MIN
+// #55 crash when value_.at(n).first == LONG_MIN
 #define LARGE_INT 1000000
     // Specialization for rational
     template<>
     inline long ValueType<Rational>::toLong(long n) const
     {
-        ok_ = (value_[n].second != 0 && INT_MIN < value_[n].first && value_[n].first < INT_MAX );
+        ok_ = (value_.at(n).second != 0 && INT_MIN < value_.at(n).first && value_.at(n).first < INT_MAX );
         if (!ok_) return 0;
-        return value_[n].first / value_[n].second;
+        return value_.at(n).first / value_.at(n).second;
     }
     // Specialization for unsigned rational
     template<>
     inline long ValueType<URational>::toLong(long n) const
     {
-        ok_ = (value_[n].second != 0 && value_[n].first < LARGE_INT);
+        ok_ = (value_.at(n).second != 0 && value_.at(n).first < LARGE_INT);
         if (!ok_) return 0;
-        return value_[n].first / value_[n].second;
+        return value_.at(n).first / value_.at(n).second;
     }
     // Default implementation
     template<typename T>
     float ValueType<T>::toFloat(long n) const
     {
         ok_ = true;
-        return static_cast<float>(value_[n]);
+        return static_cast<float>(value_.at(n));
     }
     // Specialization for rational
     template<>
     inline float ValueType<Rational>::toFloat(long n) const
     {
-        ok_ = (value_[n].second != 0);
+        ok_ = (value_.at(n).second != 0);
         if (!ok_) return 0.0f;
-        return static_cast<float>(value_[n].first) / value_[n].second;
+        return static_cast<float>(value_.at(n).first) / value_.at(n).second;
     }
     // Specialization for unsigned rational
     template<>
     inline float ValueType<URational>::toFloat(long n) const
     {
-        ok_ = (value_[n].second != 0);
+        ok_ = (value_.at(n).second != 0);
         if (!ok_) return 0.0f;
-        return static_cast<float>(value_[n].first) / value_[n].second;
+        return static_cast<float>(value_.at(n).first) / value_.at(n).second;
     }
     // Default implementation
     template<typename T>
     Rational ValueType<T>::toRational(long n) const
     {
         ok_ = true;
-        return Rational(value_[n], 1);
+        return Rational(value_.at(n), 1);
     }
     // Specialization for rational
     template<>
     inline Rational ValueType<Rational>::toRational(long n) const
     {
         ok_ = true;
-        return Rational(value_[n].first, value_[n].second);
+        return Rational(value_.at(n).first, value_.at(n).second);
     }
     // Specialization for unsigned rational
     template<>
     inline Rational ValueType<URational>::toRational(long n) const
     {
         ok_ = true;
-        return Rational(value_[n].first, value_[n].second);
+        return Rational(value_.at(n).first, value_.at(n).second);
     }
     // Specialization for float.
     template<>
@@ -1694,7 +1694,7 @@ namespace Exiv2 {
     {
         ok_ = true;
         // Warning: This is a very simple conversion, see floatToRationalCast()
-        return floatToRationalCast(value_[n]);
+        return floatToRationalCast(value_.at(n));
     }
     // Specialization for double.
     template<>
@@ -1702,7 +1702,7 @@ namespace Exiv2 {
     {
         ok_ = true;
         // Warning: This is a very simple conversion, see floatToRationalCast()
-        return floatToRationalCast(static_cast<float>(value_[n]));
+        return floatToRationalCast(static_cast<float>(value_.at(n)));
     }
 
     template<typename T>

src/crwimage_int.cpp

@@ -908,7 +908,7 @@ namespace Exiv2 {
         assert(pCrwMapping != 0);
         ULongValue v;
         v.read(ciffComponent.pData(), 8, byteOrder);
-        time_t t = v.value_[0];
+        time_t t = v.value_.at(0);
         struct tm* tm = std::localtime(&t);
         if (tm) {
             const size_t m = 20;

src/exif.cpp

@@ -229,7 +229,22 @@ namespace Exiv2 {
               fct = nullptr;
             }
         }
-        if ( fct ) fct(os, value(), pMetadata);
+        if ( fct ) {
+          // https://github.com/Exiv2/exiv2/issues/1706
+          // Sometimes the type of the value doesn't match what the
+          // print function expects. (The expected types are stored
+          // in the TagInfo tables, but they are not enforced when the
+          // metadata is parsed.) These type mismatches can sometimes
+          // cause a std::out_of_range exception to be thrown.
+          try {
+            fct(os, value(), pMetadata);
+          } catch (std::out_of_range&) {
+            os << "Bad value";
+#ifdef EXIV2_DEBUG_MESSAGES
+            std::cerr << "Caught std::out_of_range exception in Exifdatum::write().\n";
+#endif
+          }
+        }
         return os;
     }
 

src/value.cpp

@@ -203,7 +203,7 @@ namespace Exiv2 {
     {
         std::vector<byte>::size_type end = value_.size();
         for (std::vector<byte>::size_type i = 0; i != end; ++i) {
-            os << static_cast<int>(value_[i]);
+            os << static_cast<int>(value_.at(i));
             if (i < end - 1) os << " ";
         }
         return os;
@@ -212,7 +212,7 @@ namespace Exiv2 {
     std::string DataValue::toString(long n) const
     {
         std::ostringstream os;
-        os << static_cast<int>(value_[n]);
+        os << static_cast<int>(value_.at(n));
         ok_ = !os.fail();
         return os.str();
     }
@@ -220,19 +220,19 @@ namespace Exiv2 {
     long DataValue::toLong(long n) const
     {
         ok_ = true;
-        return value_[n];
+        return value_.at(n);
     }
 
     float DataValue::toFloat(long n) const
     {
         ok_ = true;
-        return value_[n];
+        return value_.at(n);
     }
 
     Rational DataValue::toRational(long n) const
     {
         ok_ = true;
-        return {value_[n], 1};
+        return {value_.at(n), 1};
     }
 
     StringValueBase::StringValueBase(TypeId typeId)
@@ -296,19 +296,19 @@ namespace Exiv2 {
     long StringValueBase::toLong(long n) const
     {
         ok_ = true;
-        return value_[n];
+        return value_.at(n);
     }
 
     float StringValueBase::toFloat(long n) const
     {
         ok_ = true;
-        return value_[n];
+        return value_.at(n);
     }
 
     Rational StringValueBase::toRational(long n) const
     {
         ok_ = true;
-        return {value_[n], 1};
+        return {value_.at(n), 1};
     }
 
     StringValue::StringValue()
@@ -340,8 +340,9 @@ namespace Exiv2 {
     {
         value_ = buf;
         // ensure count>0 and nul terminated # https://github.com/Exiv2/exiv2/issues/1484
-        if (value_.empty() || value_[value_.size() - 1] != '\0')
+        if (value_.empty() || value_.at(value_.size() - 1) != '\0') {
             value_ += '\0';
+        }
         return 0;
     }
 
@@ -740,22 +741,22 @@ namespace Exiv2 {
     std::string XmpArrayValue::toString(long n) const
     {
         ok_ = true;
-        return value_[n];
+        return value_.at(n);
     }
 
     long XmpArrayValue::toLong(long n) const
     {
-        return parseLong(value_[n], ok_);
+        return parseLong(value_.at(n), ok_);
     }
 
     float XmpArrayValue::toFloat(long n) const
     {
-        return parseFloat(value_[n], ok_);
+        return parseFloat(value_.at(n), ok_);
     }
 
     Rational XmpArrayValue::toRational(long n) const
     {
-        return parseRational(value_[n], ok_);
+        return parseRational(value_.at(n), ok_);
     }
 
     XmpArrayValue* XmpArrayValue::clone_() const

tests/bugfixes/github/test_issue_1706.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+
+from system_tests import CaseMeta, path
+
+
+class InvalidDateXMP(metaclass=CaseMeta):
+    """
+    Regression test for the bug described in:
+    https://github.com/Exiv2/exiv2/issues/1706
+    """
+    url = "https://github.com/Exiv2/exiv2/issues/1706"
+
+    filename = path("$data_path/issue_1706_poc.exv")
+    commands = ["$exiv2 -PE $filename"]
+
+    stderr = [
+"""Error: Directory Photo with 65280 entries considered invalid; not read.
+"""
+]
+    retval = [0]
+
+    def compare_stdout(self, i, command, got_stdout, expected_stdout):
+        # Check that it printed "Bad value" for the date.
+        self.assertRegex(got_stdout, "Exif.PentaxDng.Date\\s+Long\\s+1\\s+Bad value")