Fix write-heap-buffer-overflow in et_copy_index

kernels/prim_ops/et_copy_index.cpp

@@ -59,7 +59,7 @@ constexpr size_t kTensorDimensionLimit = 16;
 //        torch.ops.executorch.prim.add.int(iteration_index, 1, iteration_index)
 //        done_bool = torch.ops.executorch.prim.eq.int(iteration_index,
 //        sym_size, done_bool) # Emitter inserts a instruction here, if
-//        done_bool == False jump to selcect_copy op # if not continue. return
+//        done_bool == False jump to select_copy op # if not continue. return
 //        add_tensor
 //
 // The output of each iteration (copy_from) is copied into the copy_to tensor at
@@ -79,12 +79,24 @@ void et_copy_index(KernelRuntimeContext& context, Span<EValue*> stack) {
   auto copy_from = (*stack[1]).toTensor();
   auto index = (*stack[2]).toInt();
 
+  ET_KERNEL_CHECK_MSG(
+      context,
+      index >= 0,
+      InvalidArgument,
+      /* void */,
+      "Expected index to be non-negative.");
+
   // Number of bytes we need to copy over from copy_from tensor.
   size_t size_copy_from = (copy_from.element_size()) * (copy_from.numel());
 
-  ET_CHECK_MSG(
+  ET_KERNEL_CHECK_MSG(
+      context,
       (copy_to.sizes().size() - copy_from.sizes().size()) == 1,
-      "Ranks of copy_to  and copy_from tensor should only differ by 1.");
+      InvalidArgument,
+      /* void */,
+      "Ranks of copy_to %zu and copy_from tensor %zu should only differ by 1.",
+      copy_to.sizes().size(),
+      copy_from.sizes().size());
 
   // Here we calculate the size of the out_tensor after copy_from has
   // been copied to it. This will be passed onto the resize call.
@@ -93,8 +105,11 @@ void et_copy_index(KernelRuntimeContext& context, Span<EValue*> stack) {
     // If we're copying past the first index then the shape of
     // copy_from and copy_to without the leading dimension should be
     // the same. i.e. copy_to.size[1:] == copy_from.size[:].
-    ET_CHECK_MSG(
+    ET_KERNEL_CHECK_MSG(
+        context,
         copy_to.sizes()[i + 1] == copy_from.sizes()[i],
+        InvalidArgument,
+        /* void */,
         "Mismatch in shape between copy_to and copy_from tensors");
     expected_output_size[i + 1] = copy_from.sizes()[i];
   }
@@ -105,11 +120,22 @@ void et_copy_index(KernelRuntimeContext& context, Span<EValue*> stack) {
     Error err =
         resize_tensor(copy_to, {expected_output_size, copy_to.sizes().size()});
     ET_CHECK(err == Error::Ok);
-    ET_CHECK_MSG(
+    ET_KERNEL_CHECK_MSG(
+        context,
         data_ptr == copy_to.const_data_ptr(),
+        InvalidState,
+        /* void */,
         "Data ptr of copy_to tensor changed after resize which isn't allowed for static/upper-bounded tensors");
   }
 
+  // After potential resize, verify that index is within bounds.
+  ET_KERNEL_CHECK_MSG(
+      context,
+      index < copy_to.sizes()[0],
+      InvalidArgument,
+      /* void */,
+      "Index out of bounds");
+
   auto copy_to_ptr = copy_to.const_data_ptr();
   auto copy_from_ptr = copy_from.const_data_ptr();
 
@@ -118,12 +144,22 @@ void et_copy_index(KernelRuntimeContext& context, Span<EValue*> stack) {
   // copy_from into the copy_to tensor.
 
   // Check that the destination has enough space for the copy.
+  ET_KERNEL_CHECK_MSG(
+      context,
+      size_copy_from == 0 ||
+          static_cast<size_t>(index) <= SIZE_MAX / size_copy_from,
+      InvalidArgument,
+      /* void */,
+      "Offset multiplication .");
   size_t offset = index * size_copy_from;
   size_t copy_to_size = copy_to.element_size() * copy_to.numel();
-  ET_CHECK_MSG(
-      offset + size_copy_from <= copy_to_size,
-      "Buffer overflow: copy_to tensor is smaller than copy_from tensor.");
-
+  ET_KERNEL_CHECK_MSG(
+      context,
+      (offset <= SIZE_MAX - size_copy_from) &&
+          (offset + size_copy_from <= copy_to_size),
+      InvalidArgument,
+      /* void */,
+      "Buffer overflow; offset overflow or copy_to tensor is smaller than copy_from tensor.");
   memcpy(
       // NOLINTNEXTLINE(performance-no-int-to-ptr)
       (void*)((uintptr_t)copy_to_ptr + offset),

kernels/prim_ops/test/prim_ops_test.cpp

@@ -276,8 +276,9 @@ TEST_F(RegisterPrimOpsTest, TestETCopyIndexMismatchShape) {
   // Try to copy and replace at index 1. This will fail because
   // copy_to.sizes[1:] and to_copy.sizes[:] don't match each other
   // which is a pre-requisite for this operator.
-  ET_EXPECT_DEATH(
-      getOpsFn("executorch_prim::et_copy_index.tensor")(context_, stack), "");
+  ET_EXPECT_KERNEL_FAILURE(
+      context_,
+      getOpsFn("executorch_prim::et_copy_index.tensor")(context_, stack));
 }
 
 TEST_F(RegisterPrimOpsTest, TestETCopyIndexStaticShape) {