Add `value_validator` to `NNTree` implementations for enhanced validation.

- Introduced `std::function<bool(QPDFObjectHandle const&)>` to validate tree values. - Updated constructors and methods across `QPDFNameTreeObjectHelper` and `QPDFNumberTreeObjectHelper` to support value validation. - Refactored `NNTreeImpl` to check for invalid values during insertion, iteration, and retrieval. - Improved error handling and reporting for invalid values.

Add `value_validator` to `NNTree` implementations for enhanced validation.
- Introduced `std::function<bool(QPDFObjectHandle const&)>` to validate tree values. - Updated constructors and methods across `QPDFNameTreeObjectHelper` and `QPDFNumberTreeObjectHelper` to support value validation. - Refactored `NNTreeImpl` to check for invalid values during insertion, iteration, and retrieval. - Improved error handling and reporting for invalid values.
m-holger
1 parent 2b88c11b
Showing 6 changed files with 99 additions and 17 deletions
include/qpdf/QPDFNameTreeObjectHelper.hh
include/qpdf/QPDFNumberTreeObjectHelper.hh
libqpdf/NNTree.cc
libqpdf/QPDFNameTreeObjectHelper.cc
libqpdf/QPDFNumberTreeObjectHelper.cc
libqpdf/qpdf/NNTree.hh
@@ -45,6 +45,13 @@ class QPDF_DLL_CLASS QPDFNameTreeObjectHelper: public QPDFObjectHelper
     QPDF_DLL
     QPDFNameTreeObjectHelper(QPDFObjectHandle, QPDF&, bool auto_repair = true);
  
+    QPDF_DLL
+    QPDFNameTreeObjectHelper(
+        QPDFObjectHandle,
+        QPDF&,
+        std::function<bool(QPDFObjectHandle const&)> value_validator,
+        bool auto_repair = true);
+
     // Create an empty name tree
     QPDF_DLL
     static QPDFNameTreeObjectHelper newEmpty(QPDF&, bool auto_repair = true);
@@ -171,7 +178,11 @@ class QPDF_DLL_CLASS QPDFNameTreeObjectHelper: public QPDFObjectHelper
         ~Members() = default;
  
       private:
-        Members(QPDFObjectHandle& oh, QPDF&, bool auto_repair);
+        Members(
+            QPDFObjectHandle& oh,
+            QPDF&,
+            std::function<bool(QPDFObjectHandle const&)> value_validator,
+            bool auto_repair);
         Members(Members const&) = delete;
  
         std::shared_ptr<NNTreeImpl> impl;
@@ -44,6 +44,13 @@ class QPDF_DLL_CLASS QPDFNumberTreeObjectHelper: public QPDFObjectHelper
     QPDFNumberTreeObjectHelper(QPDFObjectHandle, QPDF&, bool auto_repair = true);
  
     QPDF_DLL
+    QPDFNumberTreeObjectHelper(
+        QPDFObjectHandle,
+        QPDF&,
+        std::function<bool(QPDFObjectHandle const&)> value_validator,
+        bool auto_repair = true);
+
+    QPDF_DLL
     ~QPDFNumberTreeObjectHelper() override;
  
     // Create an empty number tree
@@ -188,7 +195,11 @@ class QPDF_DLL_CLASS QPDFNumberTreeObjectHelper: public QPDFObjectHelper
         ~Members() = default;
  
       private:
-        Members(QPDFObjectHandle& oh, QPDF&, bool auto_repair);
+        Members(
+            QPDFObjectHandle& oh,
+            QPDF&,
+            std::function<bool(QPDFObjectHandle const&)> value_validator,
+            bool auto_repair);
         Members(Members const&) = delete;
  
         std::shared_ptr<NNTreeImpl> impl;
@@ -141,8 +141,8 @@ NNTreeIterator::increment(bool backward)
                 impl.warn(node, "items array doesn't have enough elements");
             } else if (!impl.details.keyValid(items[item_number])) {
                 impl.warn(node, ("item " + std::to_string(item_number) + " has the wrong type"));
-            } else if (!items[item_number + 1]) {
-                impl.warn(node, "item " + std::to_string(item_number) + " is null");
+            } else if (!impl.value_valid(items[item_number + 1])) {
+                impl.warn(node, "item " + std::to_string(item_number + 1) + " is invalid");
             } else {
                 return;
             }
@@ -386,6 +386,9 @@ NNTreeIterator::insertAfter(QPDFObjectHandle const&amp; key, QPDFObjectHandle const&amp;
     if (!(key && value)) {
         impl.error(node, "insert: key or value is null");
     }
+    if (!impl.value_valid(value)) {
+        impl.error(node, "insert: value is invalid");
+    }
     items.insert(item_number + 2, key);
     items.insert(item_number + 3, value);
     resetLimits(node, lastPathElement());
@@ -621,10 +624,15 @@ NNTreeIterator::deepen(QPDFObjectHandle a_node, bool first, bool allow_empty)
 }
  
 NNTreeImpl::NNTreeImpl(
-    NNTreeDetails const& details, QPDF& qpdf, QPDFObjectHandle& oh, bool auto_repair) :
+    NNTreeDetails const& details,
+    QPDF& qpdf,
+    QPDFObjectHandle& oh,
+    std::function<bool(QPDFObjectHandle const&)> value_validator,
+    bool auto_repair) :
     details(details),
     qpdf(qpdf),
     oh(oh),
+    value_valid(value_validator),
     auto_repair(auto_repair)
 {
 }
@@ -740,7 +748,7 @@ NNTreeImpl::repair()
 {
     auto new_node = QPDFObjectHandle::newDictionary();
     new_node.replaceKey(details.itemsKey(), Array());
-    NNTreeImpl repl(details, qpdf, new_node, false);
+    NNTreeImpl repl(details, qpdf, new_node, value_valid, false);
     for (auto const& [key, value]: *this) {
         if (key && value) {
             repl.insert(key, value);
@@ -774,10 +782,17 @@ NNTreeImpl::findInternal(QPDFObjectHandle const&amp; key, bool return_prev_if_not_fo
     if (first_item == end()) {
         return end();
     }
-    if (first_item.valid() && details.keyValid(first_item->first) &&
-        details.compareKeys(key, first_item->first) < 0) {
-        // Before the first key
-        return end();
+    if (first_item.valid()) {
+        if (!details.keyValid(first_item->first)) {
+            error(oh, "encountered invalid key in find");
+        }
+        if (!value_valid(first_item->second)) {
+            error(oh, "encountered invalid value in find");
+        }
+        if (details.compareKeys(key, first_item->first) < 0) {
+            // Before the first key
+            return end();
+        }
     }
     qpdf_assert_debug(!last_item.valid());
  
@@ -797,6 +812,12 @@ NNTreeImpl::findInternal(QPDFObjectHandle const&amp; key, bool return_prev_if_not_fo
                 key, items, nitems / 2, return_prev_if_not_found, &NNTreeImpl::compareKeyItem);
             if (idx >= 0) {
                 result.setItemNumber(node, 2 * idx);
+                if (!result.impl.details.keyValid(result.ivalue.first)) {
+                    error(node, "encountered invalid key in find");
+                }
+                if (!result.impl.value_valid(result.ivalue.second)) {
+                    error(oh, "encountered invalid value in find");
+                }
             }
             return result;
         }
@@ -830,6 +851,9 @@ NNTreeImpl::insertFirst(QPDFObjectHandle const&amp; key, QPDFObjectHandle const&amp; val
     if (!(key && value)) {
         error(oh, "unable to insert null key or value");
     }
+    if (!value_valid(value)) {
+        error(oh, "attempting to insert an invalid value");
+    }
     items.insert(0, key);
     items.insert(1, value);
     iter.setItemNumber(iter.node, 0);
@@ -40,14 +40,29 @@ QPDFNameTreeObjectHelper::~QPDFNameTreeObjectHelper() // NOLINT (modernize-use-e
     // class, see github issue #745.
 }
  
-QPDFNameTreeObjectHelper::Members::Members(QPDFObjectHandle& oh, QPDF& q, bool auto_repair) :
-    impl(std::make_shared<NNTreeImpl>(name_tree_details, q, oh, auto_repair))
+QPDFNameTreeObjectHelper::Members::Members(
+    QPDFObjectHandle& oh,
+    QPDF& q,
+    std::function<bool(QPDFObjectHandle const&)> value_validator,
+    bool auto_repair) :
+    impl(std::make_shared<NNTreeImpl>(name_tree_details, q, oh, value_validator, auto_repair))
 {
 }
  
 QPDFNameTreeObjectHelper::QPDFNameTreeObjectHelper(QPDFObjectHandle oh, QPDF& q, bool auto_repair) :
     QPDFObjectHelper(oh),
-    m(new Members(oh, q, auto_repair))
+    m(new Members(
+        oh, q, [](QPDFObjectHandle const& o) -> bool { return static_cast<bool>(o); }, auto_repair))
+{
+}
+
+QPDFNameTreeObjectHelper::QPDFNameTreeObjectHelper(
+    QPDFObjectHandle oh,
+    QPDF& q,
+    std::function<bool(QPDFObjectHandle const&)> value_validator,
+    bool auto_repair) :
+    QPDFObjectHelper(oh),
+    m(new Members(oh, q, value_validator, auto_repair))
 {
 }
  
@@ -41,15 +41,30 @@ QPDFNumberTreeObjectHelper::~QPDFNumberTreeObjectHelper() // NOLINT (modernize-u
     // class, see github issue #745.
 }
  
-QPDFNumberTreeObjectHelper::Members::Members(QPDFObjectHandle& oh, QPDF& q, bool auto_repair) :
-    impl(std::make_shared<NNTreeImpl>(number_tree_details, q, oh, auto_repair))
+QPDFNumberTreeObjectHelper::Members::Members(
+    QPDFObjectHandle& oh,
+    QPDF& q,
+    std::function<bool(QPDFObjectHandle const&)> value_validator,
+    bool auto_repair) :
+    impl(std::make_shared<NNTreeImpl>(number_tree_details, q, oh, value_validator, auto_repair))
 {
 }
  
 QPDFNumberTreeObjectHelper::QPDFNumberTreeObjectHelper(
     QPDFObjectHandle oh, QPDF& q, bool auto_repair) :
     QPDFObjectHelper(oh),
-    m(new Members(oh, q, auto_repair))
+    m(new Members(
+        oh, q, [](QPDFObjectHandle const& o) -> bool { return static_cast<bool>(o); }, auto_repair))
+{
+}
+
+QPDFNumberTreeObjectHelper::QPDFNumberTreeObjectHelper(
+    QPDFObjectHandle oh,
+    QPDF& q,
+    std::function<bool(QPDFObjectHandle const&)> value_validator,
+    bool auto_repair) :
+    QPDFObjectHelper(oh),
+    m(new Members(oh, q, value_validator, auto_repair))
 {
 }
  
@@ -95,7 +95,12 @@ class NNTreeImpl
   public:
     typedef NNTreeIterator iterator;
  
-    NNTreeImpl(NNTreeDetails const&, QPDF&, QPDFObjectHandle&, bool auto_repair = true);
+    NNTreeImpl(
+        NNTreeDetails const&,
+        QPDF&,
+        QPDFObjectHandle&,
+        std::function<bool(QPDFObjectHandle const&)> value_validator,
+        bool auto_repair = true);
     iterator begin();
     iterator end();
     iterator last();
@@ -127,6 +132,7 @@ class NNTreeImpl
     QPDF& qpdf;
     int split_threshold{32};
     QPDFObjectHandle oh;
+    const std::function<bool(QPDFObjectHandle const&)> value_valid;
     bool auto_repair{true};
     size_t error_count{0};
 };