[Lldb-commits] [lldb] [lldb] Speedup AppleObjCRuntimeV2 UpdateIfNeeded (PR #211774)

[Raphael Isemann via lldb-commits]

================
@@ -1819,23 +1821,35 @@ llvm::Error AppleObjCRuntimeV2::SharedCacheImageHeaders::UpdateIfNeeded() {
   constexpr lldb::addr_t metadata_size =
       sizeof(uint32_t) + sizeof(uint32_t); // count + entsize
 
-  Status error;
+  /// Sanity check: m_count and m_entsize are external input, guard against
+  /// invalid values using an arbitrary 1GB maximum size.
+  const size_t memory_needed = static_cast<size_t>(m_count) * m_entsize;
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Teemperor wrote:

You could also do this:

```cpp
if (llvm::AddOverflow<size_t>(m_count, m_entsize, /*Result=*/memory_needed))
  return llvm::createStringError("Shared Cache size computation overflowed");
```

Having said that, we essentially just blindly read what the runtime tells us, so it's not really important that we sanitise input here...


https://github.com/llvm/llvm-project/pull/211774