From daaaab25fb8aa981fdf76740763714c9ea3f2879 Mon Sep 17 00:00:00 2001
From: Akshay Modi <nareshmodi@google.com>
Date: Thu, 2 Aug 2018 15:27:04 -0700
Subject: Check if the handle is nullptr, and fail early instead of
 segfaulting.

PiperOrigin-RevId: 207176253
---
 tensorflow/c/eager/c_api.cc      | 20 ++++++++++++++++++++
 tensorflow/c/eager/c_api_test.cc | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

(limited to 'tensorflow/c')

diff --git a/tensorflow/c/eager/c_api.cc b/tensorflow/c/eager/c_api.cc
index 7321b4b791..555dab3e89 100644
--- a/tensorflow/c/eager/c_api.cc
+++ b/tensorflow/c/eager/c_api.cc
@@ -348,6 +348,11 @@ TF_DataType TFE_TensorHandleDataType(TFE_TensorHandle* h) {
 }
 
 int TFE_TensorHandleNumDims(TFE_TensorHandle* h, TF_Status* status) {
+  if (h == nullptr || h->handle == nullptr) {
+    status->status = tensorflow::errors::InvalidArgument(
+        "The passed in handle is a nullptr");
+    return -1;
+  }
   int result;
   status->status = h->handle->NumDims(&result);
   return result;
@@ -355,12 +360,22 @@ int TFE_TensorHandleNumDims(TFE_TensorHandle* h, TF_Status* status) {
 
 int64_t TFE_TensorHandleDim(TFE_TensorHandle* h, int dim_index,
                             TF_Status* status) {
+  if (h == nullptr || h->handle == nullptr) {
+    status->status = tensorflow::errors::InvalidArgument(
+        "The passed in handle is a nullptr");
+    return -1;
+  }
   tensorflow::int64 result;
   status->status = h->handle->Dim(dim_index, &result);
   return result;
 }
 
 const char* TFE_TensorHandleDeviceName(TFE_TensorHandle* h, TF_Status* status) {
+  if (h == nullptr || h->handle == nullptr) {
+    status->status = tensorflow::errors::InvalidArgument(
+        "The passed in handle is a nullptr");
+    return nullptr;
+  }
   tensorflow::Device* d = nullptr;
   status->status = h->handle->OpDevice(&d);
   return (d == nullptr) ? "/job:localhost/replica:0/task:0/device:CPU:0"
@@ -368,6 +383,11 @@ const char* TFE_TensorHandleDeviceName(TFE_TensorHandle* h, TF_Status* status) {
 }
 
 TF_Tensor* TFE_TensorHandleResolve(TFE_TensorHandle* h, TF_Status* status) {
+  if (h == nullptr || h->handle == nullptr) {
+    status->status = tensorflow::errors::InvalidArgument(
+        "The passed in handle is a nullptr");
+    return nullptr;
+  }
   // TODO(agarwal): move this implementation inside TFE_TensorHandle.
   tensorflow::Device* d = nullptr;
   tensorflow::Device* op_device = nullptr;
diff --git a/tensorflow/c/eager/c_api_test.cc b/tensorflow/c/eager/c_api_test.cc
index 0bdea70fe6..6f2fbee884 100644
--- a/tensorflow/c/eager/c_api_test.cc
+++ b/tensorflow/c/eager/c_api_test.cc
@@ -615,6 +615,42 @@ void SetAndGetOpDevices(bool async) {
   TF_DeleteStatus(status);
 }
 
+TEST(CAPI, TensorHandleNullptr) {
+  TFE_TensorHandle* h = nullptr;
+  std::unique_ptr<TF_Status, decltype(&TF_DeleteStatus)> status(
+      TF_NewStatus(), TF_DeleteStatus);
+
+  TF_Tensor* t = TFE_TensorHandleResolve(h, status.get());
+  ASSERT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(status.get()));
+  ASSERT_EQ(t, nullptr);
+  ASSERT_EQ("The passed in handle is a nullptr",
+            string(TF_Message(status.get())));
+
+  TF_SetStatus(status.get(), TF_OK, "");
+
+  const char* device_name = TFE_TensorHandleDeviceName(h, status.get());
+  ASSERT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(status.get()));
+  ASSERT_EQ(device_name, nullptr);
+  ASSERT_EQ("The passed in handle is a nullptr",
+            string(TF_Message(status.get())));
+
+  TF_SetStatus(status.get(), TF_OK, "");
+
+  int num_dims = TFE_TensorHandleNumDims(h, status.get());
+  ASSERT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(status.get()));
+  ASSERT_EQ(num_dims, -1);
+  ASSERT_EQ("The passed in handle is a nullptr",
+            string(TF_Message(status.get())));
+
+  TF_SetStatus(status.get(), TF_OK, "");
+
+  int dim = TFE_TensorHandleDim(h, 0, status.get());
+  ASSERT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(status.get()));
+  ASSERT_EQ(dim, -1);
+  ASSERT_EQ("The passed in handle is a nullptr",
+            string(TF_Message(status.get())));
+}
+
 void Execute_MatMul_CPU(bool async) {
   TF_Status* status = TF_NewStatus();
   TFE_ContextOptions* opts = TFE_NewContextOptions();
-- 
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