Merge pull request #442 from open-source-parsers/JSONCPP_STRING

Secure allocator available for wiping memory.

Resolves #437.
Resolves #152.

Author: cdunn2001

.gitignore

@@ -45,3 +45,8 @@ jsoncpp_lib_static.dir/
 /src/lib_json/Makefile
 /src/test_lib_json/Makefile
 /src/test_lib_json/jsoncpp_test
+
+# eclipse project files
+.project
+.cproject
+/.settings/

CMakeLists.txt

@@ -69,6 +69,7 @@ jsoncpp_parse_version( ${JSONCPP_VERSION} JSONCPP_VERSION )
 #IF(NOT JSONCPP_VERSION_FOUND)
 #    MESSAGE(FATAL_ERROR "Failed to parse version string properly. Expect X.Y.Z")
 #ENDIF(NOT JSONCPP_VERSION_FOUND)
+SET( JSONCPP_USE_SECURE_MEMORY "0" CACHE STRING "-D...=1 to use memory-wiping allocator for STL" )
 
 MESSAGE(STATUS "JsonCpp Version: ${JSONCPP_VERSION_MAJOR}.${JSONCPP_VERSION_MINOR}.${JSONCPP_VERSION_PATCH}")
 # File version.h is only regenerated on CMake configure step

amalgamate.py

@@ -67,6 +67,7 @@ def amalgamate_source(source_top_dir=None,
     header.add_text("/// to prevent private header inclusion.")
     header.add_text("#define JSON_IS_AMALGAMATION")
     header.add_file("include/json/version.h")
+    header.add_file("include/json/allocator.h")
     header.add_file("include/json/config.h")
     header.add_file("include/json/forwards.h")
     header.add_file("include/json/features.h")

include/json/allocator.h

@@ -0,0 +1,94 @@
+// Copyright 2007-2010 Baptiste Lepilleur
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef CPPTL_JSON_ALLOCATOR_H_INCLUDED
+#define CPPTL_JSON_ALLOCATOR_H_INCLUDED
+
+#include <cstring>
+#include <memory>
+
+namespace Json {
+template<typename T>
+class SecureAllocator {
+	public:
+		// Type definitions
+		using value_type      = T;
+		using pointer         = T*;
+		using const_pointer   = const T*;
+		using reference       = T&;
+		using const_reference = const T&;
+		using size_type       = std::size_t;
+		using difference_type = std::ptrdiff_t;
+
+		/**
+		 * Allocate memory for N items using the standard allocator.
+		 */
+		pointer allocate(size_type n) {
+			// allocate using "global operator new"
+			return static_cast<pointer>(::operator new(n * sizeof(T)));
+		}
+
+		/**
+		 * Release memory which was allocated for N items at pointer P.
+		 *
+		 * The memory block is filled with zeroes before being released.
+		 * The pointer argument is tagged as "volatile" to prevent the
+		 * compiler optimizing out this critical step.
+		 */
+		void deallocate(volatile pointer p, size_type n) {
+			std::memset(p, 0, n * sizeof(T));
+			// free using "global operator delete"
+			::operator delete(p);
+		}
+
+		/**
+		 * Construct an item in-place at pointer P.
+		 */
+		template<typename... Args>
+		void construct(pointer p, Args&&... args) {
+			// construct using "placement new" and "perfect forwarding"
+			::new (static_cast<void*>(p)) T(std::forward<Args>(args)...);
+		}
+
+		size_type max_size() const {
+			return size_t(-1) / sizeof(T);
+		}
+
+		pointer address( reference x ) const {
+			return std::addressof(x);
+		}
+
+		const_pointer address( const_reference x ) const {
+			return std::addressof(x);
+		}
+
+		/**
+		 * Destroy an item in-place at pointer P.
+		 */
+		void destroy(pointer p) {
+			// destroy using "explicit destructor"
+			p->~T();
+		}
+
+		// Boilerplate
+		SecureAllocator() {}
+		template<typename U> SecureAllocator(const SecureAllocator<U>&) {}
+		template<typename U> struct rebind { using other = SecureAllocator<U>; };
+};
+
+
+template<typename T, typename U>
+bool operator==(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+	return true;
+}
+
+template<typename T, typename U>
+bool operator!=(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+	return false;
+}
+
+} //namespace Json
+
+#endif // CPPTL_JSON_ALLOCATOR_H_INCLUDED

include/json/config.h

@@ -119,6 +119,12 @@
 #  define JSON_USE_INT64_DOUBLE_CONVERSION 1
 #endif
 
+#include "version.h"
+
+#if JSONCPP_USING_SECURE_MEMORY
+#include "allocator.h" //typedef Allocator
+#endif
+
 namespace Json {
 typedef int Int;
 typedef unsigned int UInt;
@@ -139,11 +145,19 @@ typedef Int64 LargestInt;
 typedef UInt64 LargestUInt;
 #define JSON_HAS_INT64
 #endif // if defined(JSON_NO_INT64)
+#if JSONCPP_USING_SECURE_MEMORY
+#define JSONCPP_STRING        std::basic_string<char, std::char_traits<char>, Json::SecureAllocator<char> >
+#define JSONCPP_OSTRINGSTREAM std::basic_ostringstream<char, std::char_traits<char>, Json::SecureAllocator<char> >
+#define JSONCPP_OSTREAM       std::basic_ostream<char, std::char_traits<char>>
+#define JSONCPP_ISTRINGSTREAM std::basic_istringstream<char, std::char_traits<char>, Json::SecureAllocator<char> >
+#define JSONCPP_ISTREAM       std::istream
+#else
 #define JSONCPP_STRING        std::string
 #define JSONCPP_OSTRINGSTREAM std::ostringstream
 #define JSONCPP_OSTREAM       std::ostream
 #define JSONCPP_ISTRINGSTREAM std::istringstream
 #define JSONCPP_ISTREAM       std::istream
+#endif // if JSONCPP_USING_SECURE_MEMORY
 } // end namespace Json
 
 #endif // JSON_CONFIG_H_INCLUDED

include/json/value.h

@@ -336,6 +336,9 @@ Json::Value obj_value(Json::objectValue); // {}
   int compare(const Value& other) const;
 
   const char* asCString() const; ///< Embedded zeroes could cause you trouble!
+#if JSONCPP_USING_SECURE_MEMORY
+  unsigned getCStringLength() const; //Allows you to understand the length of the CString
+#endif
   JSONCPP_STRING asString() const; ///< Embedded zeroes are possible.
   /** Get raw char* of string-value.
    *  \return false if !string. (Seg-fault if str or end are NULL.)

include/json/version.h

@@ -10,4 +10,11 @@
 # define JSONCPP_VERSION_QUALIFIER
 # define JSONCPP_VERSION_HEXA ((JSONCPP_VERSION_MAJOR << 24) | (JSONCPP_VERSION_MINOR << 16) | (JSONCPP_VERSION_PATCH << 8))
 
+#ifdef JSONCPP_USING_SECURE_MEMORY
+#undef JSONCPP_USING_SECURE_MEMORY
+#endif
+#define JSONCPP_USING_SECURE_MEMORY 1
+// If non-zero, the library zeroes any memory that it has allocated before
+// it frees its memory.
+
 #endif // JSON_VERSION_H_INCLUDED

src/jsontestrunner/main.cpp

@@ -33,9 +33,6 @@ static JSONCPP_STRING normalizeFloatingPointStr(double value) {
 #endif
   buffer[sizeof(buffer) - 1] = 0;
   JSONCPP_STRING s(buffer);
-#if JSON_USE_SECURE_MEMORY
-  memset(&buffer, 0, sizeof(buffer));
-#endif
   JSONCPP_STRING::size_type index = s.find_last_of("eE");
   if (index != JSONCPP_STRING::npos) {
     JSONCPP_STRING::size_type hasSign =
@@ -69,9 +66,6 @@ static JSONCPP_STRING readInputTestFile(const char* path) {
   if (fread(buffer, 1, usize, file) == usize)
     text = buffer;
   fclose(file);
-#if JSON_USE_SECURE_MEMORY
-  memset(buffer, 0, static_cast<size_t>(size + 1));
-#endif
   delete[] buffer;
   return text;
 }
@@ -151,7 +145,7 @@ static int parseAndSaveValueTree(const JSONCPP_STRING& input,
                                  Json::Value* root)
 {
   Json::Reader reader(features);
-  bool parsingSuccessful = reader.parse(input, *root);
+  bool parsingSuccessful = reader.parse(input.data(), input.data() + input.size(), *root);
   if (!parsingSuccessful) {
     printf("Failed to parse %s file: \n%s\n",
            kind.c_str(),

src/lib_json/json_reader.cpp

@@ -98,7 +98,8 @@ Reader::Reader(const Features& features)
 
 bool
 Reader::parse(const std::string& document, Value& root, bool collectComments) {
-  document_ = document;
+  JSONCPP_STRING documentCopy(document.data(), document.data() + document.capacity());
+  std::swap(documentCopy, document_);
   const char* begin = document_.c_str();
   const char* end = begin + document_.length();
   return parse(begin, end, root, collectComments);
@@ -114,7 +115,7 @@ bool Reader::parse(std::istream& sin, Value& root, bool collectComments) {
   // create an extra copy.
   JSONCPP_STRING doc;
   std::getline(sin, doc, (char)EOF);
-  return parse(doc, root, collectComments);
+  return parse(doc.data(), doc.data() + doc.size(), root, collectComments);
 }
 
 bool Reader::parse(const char* beginDoc,

src/lib_json/json_value.cpp

@@ -138,7 +138,29 @@ inline static void decodePrefixedString(
 }
 /** Free the string duplicated by duplicateStringValue()/duplicateAndPrefixStringValue().
  */
-static inline void releaseStringValue(char* value) { free(value); }
+#if JSONCPP_USING_SECURE_MEMORY
+static inline void releasePrefixedStringValue(char* value) {
+  unsigned length = 0;
+  char const* valueDecoded;
+  decodePrefixedString(true, value, &length, &valueDecoded);
+  size_t const size = sizeof(unsigned) + length + 1U;
+  memset(value, 0, size);
+  free(value);
+}
+static inline void releaseStringValue(char* value, unsigned length) {
+  // length==0 => we allocated the strings memory
+  size_t size = (length==0) ? strlen(value) : length;
+  memset(value, 0, size);
+  free(value);
+}
+#else // !JSONCPP_USING_SECURE_MEMORY
+static inline void releasePrefixedStringValue(char* value) {
+  free(value);
+}
+static inline void releaseStringValue(char* value, unsigned length) {
+  free(value);
+}
+#endif // JSONCPP_USING_SECURE_MEMORY
 
 } // namespace Json
 
@@ -193,12 +215,12 @@ Value::CommentInfo::CommentInfo() : comment_(0)
 
 Value::CommentInfo::~CommentInfo() {
   if (comment_)
-    releaseStringValue(comment_);
+    releaseStringValue(comment_, 0u);
 }
 
 void Value::CommentInfo::setComment(const char* text, size_t len) {
   if (comment_) {
-    releaseStringValue(comment_);
+    releaseStringValue(comment_, 0u);
     comment_ = 0;
   }
   JSON_ASSERT(text != 0);
@@ -229,10 +251,10 @@ Value::CZString::CZString(char const* str, unsigned ulength, DuplicationPolicy a
   storage_.length_ = ulength & 0x3FFFFFFF;
 }
 
-Value::CZString::CZString(const CZString& other)
-    : cstr_(other.storage_.policy_ != noDuplication && other.cstr_ != 0
-                ? duplicateStringValue(other.cstr_, other.storage_.length_)
-                : other.cstr_) {
+Value::CZString::CZString(const CZString& other) {
+  cstr_ = (other.storage_.policy_ != noDuplication && other.cstr_ != 0
+				 ? duplicateStringValue(other.cstr_, other.storage_.length_)
+				 : other.cstr_);
   storage_.policy_ = static_cast<unsigned>(other.cstr_
                  ? (static_cast<DuplicationPolicy>(other.storage_.policy_) == noDuplication
                      ? noDuplication : duplicate)
@@ -248,8 +270,9 @@ Value::CZString::CZString(CZString&& other)
 #endif
 
 Value::CZString::~CZString() {
-  if (cstr_ && storage_.policy_ == duplicate)
-    releaseStringValue(const_cast<char*>(cstr_));
+  if (cstr_ && storage_.policy_ == duplicate) {
+	  releaseStringValue(const_cast<char*>(cstr_), storage_.length_ + 1u); //+1 for null terminating character for sake of completeness but not actually necessary
+  }
 }
 
 void Value::CZString::swap(CZString& other) {
@@ -455,7 +478,7 @@ Value::~Value() {
     break;
   case stringValue:
     if (allocated_)
-      releaseStringValue(value_.string_);
+      releasePrefixedStringValue(value_.string_);
     break;
   case arrayValue:
   case objectValue:
@@ -467,6 +490,8 @@ Value::~Value() {
 
   if (comments_)
     delete[] comments_;
+
+  value_.uint_ = 0;
 }
 
 Value& Value::operator=(Value other) {
@@ -611,6 +636,18 @@ const char* Value::asCString() const {
   return this_str;
 }
 
+#if JSONCPP_USING_SECURE_MEMORY
+unsigned Value::getCStringLength() const {
+  JSON_ASSERT_MESSAGE(type_ == stringValue,
+	                  "in Json::Value::asCString(): requires stringValue");
+  if (value_.string_ == 0) return 0;
+  unsigned this_len;
+  char const* this_str;
+  decodePrefixedString(this->allocated_, this->value_.string_, &this_len, &this_str);
+  return this_len;
+}
+#endif
+
 bool Value::getString(char const** str, char const** cend) const {
   if (type_ != stringValue) return false;
   if (value_.string_ == 0) return false;