A mechanism to identify/forbid/"rewrite" non-temporal instructions (and other)

src/trusted/validator/validation_disable_unsupported_test.cc

+/*
+ * Copyright (c) 2015 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gtest/gtest.h"
+
+#include "native_client/src/shared/platform/nacl_log.h"
+#include "native_client/src/shared/utils/types.h"
+#include "native_client/src/trusted/validator/ncvalidate.h"
+
+#define CODE_SIZE 32
+#define NOP 0x90
+#define MOVNTI_CODE_SIZE 8
+
+// mov %edi,%edi; movnti %rax,0x68(%r15,%rdi,1)
+const char* movnti_code = "\x89\xff\x49\x0f\xc3\x44\x3f\x68";
+
+class ValidationDisableUnsupportedTests : public ::testing::Test {
+ protected:
+  NaClValidationMetadata *metadata_ptr;
+  const struct NaClValidatorInterface *validator;
+  NaClCPUFeatures *cpu_features;
+
+  unsigned char code_buffer[CODE_SIZE];
+
+  void SetUp() {
+    metadata_ptr = NULL;
+    validator = NaClCreateValidator();
+    cpu_features = (NaClCPUFeatures *) malloc(validator->CPUFeatureSize);
+    EXPECT_NE(cpu_features, (NaClCPUFeatures *) NULL);
+    memset(cpu_features, 0, validator->CPUFeatureSize);
+    validator->SetAllCPUFeatures(cpu_features);
+    memset(code_buffer, NOP, sizeof(code_buffer));
+  }
+
+  NaClValidationStatus Validate(uint32_t flags) {
+    return validator->Validate(0, code_buffer, 32,
+                               FALSE,  /* stubout_mode */
+                               flags,
+                               FALSE,  /* readonly_test */
+                               cpu_features,
+                               metadata_ptr,
+                               NULL);
+  }
+
+  void TearDown() {
+    free(cpu_features);
+  }
+};
+
+TEST_F(ValidationDisableUnsupportedTests, NormalValidation) {
+  memcpy(code_buffer, movnti_code, MOVNTI_CODE_SIZE);
+  NaClValidationStatus status = Validate(0);
+  // If we are not disabling unsupported instructions, use the original
+  // validation rule, i.e., allow non-temporal writes. In future, we will do
+  // rewriting.
+  EXPECT_EQ(NaClValidationSucceeded, status);
+  // Code should not change.
+  EXPECT_EQ(0, memcmp(code_buffer, movnti_code, MOVNTI_CODE_SIZE));
+}
+
+TEST_F(ValidationDisableUnsupportedTests, DisableUnsupported) {
+  memcpy(code_buffer, movnti_code, MOVNTI_CODE_SIZE);
+  NaClValidationStatus status = Validate(DISABLE_UNSUPPORTED);
+  // Disable unsupported instructions, in this case, non-temporal writes.
+  EXPECT_EQ(NaClValidationFailed, status);
+  // Code should not change.
+  EXPECT_EQ(0, memcmp(code_buffer, movnti_code, MOVNTI_CODE_SIZE));
+}
+
+int main(int argc, char *argv[]) {
+  // The IllegalInst test touches the log mutex deep inside the validator.
+  // This causes an SEH exception to be thrown on Windows if the mutex is not
+  // initialized.
+  // http://code.google.com/p/nativeclient/issues/detail?id=1696
+  NaClLogModuleInit();
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}