Check if nif stream has requested amount of data

Memory allocation with initialization may take significat amount of time
if meta information does not match actual content.

components/nif/nifstream.cpp

@@ -57,6 +57,7 @@ namespace Nif
 
     std::string NIFStream::getSizedString(size_t length)
     {
+        checkStreamSize(length);
         std::string str(length, '\0');
         mStream->read(str.data(), length);
         if (mStream->fail())
@@ -90,6 +91,7 @@ namespace Nif
     std::string NIFStream::getStringPalette()
     {
         size_t size = get<uint32_t>();
+        checkStreamSize(size);
         std::string str(size, '\0');
         mStream->read(str.data(), size);
         if (mStream->fail())
@@ -235,6 +237,7 @@ namespace Nif
     {
         if (getVersion() < generateVersion(4, 1, 0, 0))
         {
+            checkStreamSize(size * sizeof(int32_t));
             std::vector<int32_t> buf(size);
             read(buf.data(), size);
             for (size_t i = 0; i < size; ++i)
@@ -242,6 +245,7 @@ namespace Nif
         }
         else
         {
+            checkStreamSize(size * sizeof(int8_t));
             std::vector<int8_t> buf(size);
             read(buf.data(), size);
             for (size_t i = 0; i < size; ++i)
@@ -264,4 +268,9 @@ namespace Nif
         }
     }
 
+    void NIFStream::checkStreamSize(std::size_t size)
+    {
+        if (size > mStreamSize)
+            throw std::runtime_error(std::format("Trying to read more than stream size: {} max={}", size, mStreamSize));
+    }
 }

components/nif/nifstream.hpp

@@ -16,6 +16,7 @@
 #include <vector>
 
 #include <components/files/istreamptr.hpp>
+#include <components/files/utils.hpp>
 #include <components/misc/endianness.hpp>
 #include <components/misc/float16.hpp>
 
@@ -78,6 +79,7 @@ namespace Nif
         Files::IStreamPtr mStream;
         const ToUTF8::StatelessUtf8Encoder* mEncoder;
         std::string mBuffer;
+        std::size_t mStreamSize;
 
     public:
         explicit NIFStream(
@@ -85,6 +87,7 @@ namespace Nif
             : mReader(reader)
             , mStream(std::move(stream))
             , mEncoder(encoder)
+            , mStreamSize(static_cast<std::size_t>(Files::getStreamSizeLeft(*mStream)))
         {
         }
 
@@ -129,6 +132,9 @@ namespace Nif
         {
             if (size == 0)
                 return;
+
+            checkStreamSize(size * sizeof(T));
+
             vec.resize(size);
             read(vec.data(), size);
         }
@@ -159,6 +165,9 @@ namespace Nif
 
         /// Read a sequence of null-terminated strings
         std::string getStringPalette();
+
+    private:
+        void checkStreamSize(std::size_t size);
     };
 
     template <>