chore: import upstream snapshot with attribution

tensorflow/security/advisory/tfsa-2021-079.md

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+## TFSA-2021-079: Null pointer dereference in TFLite's `Reshape` operator
+
+### CVE Number
+CVE-2021-29592
+
+### Impact
+The fix for [CVE-2020-15209](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15209)
+missed the case when the target shape of `Reshape` operator is given by the
+elements of a 1-D tensor. As such, the [fix for the
+vulnerability](https://github.com/tensorflow/tensorflow/blob/9c1dc920d8ffb4893d6c9d27d1f039607b326743/tensorflow/lite/core/subgraph.cc#L1062-L1074)
+allowed passing a null-buffer-backed tensor with a 1D shape:
+
+```cc
+if (tensor->data.raw == nullptr && tensor->bytes > 0) {
+  if (registration.builtin_code == kTfLiteBuiltinReshape && i == 1) {
+    // In general, having a tensor here with no buffer will be an error.
+    // However, for the reshape operator, the second input tensor is only
+    // used for the shape, not for the data. Thus, null buffer is ok.
+    continue;
+  } else {
+    // In all other cases, we need to return an error as otherwise we will
+    // trigger a null pointer dereference (likely).
+    ReportError("Input tensor %d lacks data", tensor_index);
+    return kTfLiteError;
+  }
+}
+```
+
+### Patches
+We have patched the issue in GitHub commit
+[f8378920345f4f4604202d4ab15ef64b2aceaa16](https://github.com/tensorflow/tensorflow/commit/f8378920345f4f4604202d4ab15ef64b2aceaa16).
+
+The fix will be included in TensorFlow 2.5.0. We will also cherrypick this
+commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow
+2.1.4, as these are also affected and still in supported range.
+
+### For more information
+Please consult [our security
+guide](https://github.com/tensorflow/tensorflow/blob/master/SECURITY.md) for
+more information regarding the security model and how to contact us with issues
+and questions.
+
+### Attribution
+This vulnerability has been reported by members of the Aivul Team from Qihoo
+360.