[Lldb-commits] [lldb] [lldb][windows] bound ReadProcessMemory (PR #200230)

[Charles Zablit via lldb-commits]

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@@ -614,44 +614,82 @@ static std::optional<std::string> GetFileNameByLoadAddress(HANDLE hProcess,
   return dos_path;
 }
 
+// Determine how many bytes can be read at `addr` in `hProcess` before crossing
+// out of the committed memory region containing it. Returns 0 if the address is
+// not within a committed region.
+static SIZE_T BytesReadableAt(HANDLE hProcess, LPCVOID addr) {
+  MEMORY_BASIC_INFORMATION mbi{};
+  if (!::VirtualQueryEx(hProcess, addr, &mbi, sizeof(mbi)))
+    return 0;
+  if (mbi.State != MEM_COMMIT)
+    return 0;
+  uintptr_t region_end =
+      reinterpret_cast<uintptr_t>(mbi.BaseAddress) + mbi.RegionSize;
+  uintptr_t a = reinterpret_cast<uintptr_t>(addr);
+  if (a >= region_end)
+    return 0;
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charles-zablit wrote:

It should not happen, no. I replaced the if with an assert to clarify the invariant.

https://github.com/llvm/llvm-project/pull/200230