From f4b9e54b2280eea66fe449416251d6c50ce0d3a8 Mon Sep 17 00:00:00 2001
From: Zephyron <zephyron@citron-emu.org>
Date: Sat, 1 Feb 2025 21:50:33 +1000
Subject: common/nvdrv: improve memory validation and error handling

Implements several improvements to memory handling and validation:

- host_memory: Add IsValidMapping() and IsDirectMappingEnabled() methods to
  validate memory access
- host_memory: Fix virtual base offset calculation to use proper pointer
  arithmetic
- host_memory: Add size field to track allocation size
- nvhost_ctrl_gpu: Return InvalidState instead of InvalidValue for TPC mask
  buffer size validation
- Update copyright year for citron

The changes improve memory safety by adding explicit validation checks and
fixing pointer arithmetic in the virtual memory implementation.
---
 src/common/host_memory.cpp | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

(limited to 'src/common/host_memory.cpp')

diff --git a/src/common/host_memory.cpp b/src/common/host_memory.cpp
index 4f5a11f86..4ae22fcfb 100644
--- a/src/common/host_memory.cpp
+++ b/src/common/host_memory.cpp
@@ -200,11 +200,20 @@ public:
         UNREACHABLE();
     }
 
+    bool IsValidMapping(size_t offset, size_t size) const {
+        return (offset + size) <= backing_size;
+    }
+
+    bool IsDirectMappingEnabled() const {
+        return direct_mapping_enabled;
+    }
+
     const size_t backing_size; ///< Size of the backing memory in bytes
     const size_t virtual_size; ///< Size of the virtual address placeholder in bytes
 
     u8* backing_base{};
     u8* virtual_base{};
+    bool direct_mapping_enabled{false};
 
 private:
     /// Release all resources in the object
@@ -602,6 +611,14 @@ public:
         virtual_base = nullptr;
     }
 
+    bool IsValidMapping(size_t offset, size_t size) const {
+        return (offset + size) <= backing_size;
+    }
+
+    bool IsDirectMappingEnabled() const {
+        return virtual_base == nullptr;
+    }
+
     const size_t backing_size; ///< Size of the backing memory in bytes
     const size_t virtual_size; ///< Size of the virtual address placeholder in bytes
 
@@ -675,6 +692,14 @@ public:
 
     void EnableDirectMappedAddress() {}
 
+    bool IsValidMapping(size_t offset, size_t size) const {
+        return false;
+    }
+
+    bool IsDirectMappingEnabled() const {
+        return false;
+    }
+
     u8* backing_base{nullptr};
     u8* virtual_base{nullptr};
 };
@@ -696,7 +721,9 @@ HostMemory::HostMemory(size_t backing_size_, size_t virtual_size_)
             // Ensure the virtual base is aligned to the L2 block size.
             virtual_base = reinterpret_cast<u8*>(
                 Common::AlignUp(reinterpret_cast<uintptr_t>(virtual_base), HugePageSize));
-            virtual_base_offset = virtual_base - impl->virtual_base;
+            virtual_base_offset = static_cast<size_t>(
+                reinterpret_cast<uintptr_t>(virtual_base) -
+                reinterpret_cast<uintptr_t>(impl->virtual_base));
         }
 
     } catch (const std::bad_alloc&) {
-- 
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