Fix Monero P2P remote DOS

Monero serialization reserves memory before validating the size of the
incoming data, thus allowing a remote node to send malicious data that
causes the local node to run itself out of memory.

This fixes it by limiting the amount of memory we'll reserve in advance
to a sane amount.

contrib/epee/include/epee/storages/portable_storage_from_bin.h

@@ -129,8 +129,8 @@ namespace epee
       CHECK_AND_ASSERT_THROW_MES(size <= m_count, "Size sanity check failed");
       storage_entry se{std::in_place_type<array_entry>, std::in_place_type<array_t<T>>};
       auto& arr = var::get<array_t<T>>(var::get<array_entry>(se));
-      if constexpr (!std::is_same_v<T, bool>) // bool uses a std::deque instead of vector because
-        arr.reserve(size);                    // std::vector<bool> is broken by design
+      if constexpr (!std::is_same_v<T, bool>) // bool uses a std::deque, which isn't reserveable
+        arr.reserve(std::min<size_t>(size, 4096));
 
       while(size--)
         read(arr.emplace_back());