ByteSlice: Fix persisting ptr to std::moved SSO buffer

The Bug:
1. Construct `byte_slice.portion_` with `epee::span(buffer)` which copies a pointer to the SSO buffer to `byte_slice.portion_`
2. It constructs `byte_slice.storage_` with `std::move(buffer)` (normally this swap pointers, but SSO means a memcpy and clear on the original SSO buffer)
3. `slice.data()` returns a pointer from `slice.portion_` that points to the original SSO cleared buffer, `slice.storage_` has the actual string.

1 files changed, 4 insertions, 1 deletions

diff --git a/contrib/epee/src/byte_slice.cpp b/contrib/epee/src/byte_slice.cpp
index 12cc83e6c..faf7689be 100644
--- a/contrib/epee/src/byte_slice.cpp
+++ b/contrib/epee/src/byte_slice.cpp
@@ -133,10 +133,13 @@ namespace epee
 
   template<typename T>
   byte_slice::byte_slice(const adapt_buffer, T&& buffer)
-    : storage_(nullptr), portion_(to_byte_span(to_span(buffer)))
+    : storage_(nullptr), portion_(nullptr)
   {
     if (!buffer.empty())
+    {
       storage_ = allocate_slice<adapted_byte_slice<T>>(0, std::move(buffer));
+      portion_ = to_byte_span(to_span(static_cast<adapted_byte_slice<T> *>(storage_.get())->buffer));
+    }
   }
 
   byte_slice::byte_slice(std::initializer_list<span<const std::uint8_t>> sources)