Chrome Participated Tamper Detect

components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detect_unittest.cc

Index: components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detect_unittest.cc
diff --git a/components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detect_unittest.cc b/components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detect_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f0b6fad903ae625894cacf93367997146da77bf1
--- /dev/null
+++ b/components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detect_unittest.cc
@@ -0,0 +1,1187 @@
+// Copyright 2014 The Chromium 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 "components/data_reduction_proxy/browser/data_reduction_proxy_tamper_detect.h"
+
+#include <string.h>
+#include <algorithm>
+#include <map>
+#include <vector>
+
+#include "base/base64.h"
+#include "base/md5.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "components/data_reduction_proxy/common/data_reduction_proxy_headers.h"
+#include "net/android/network_library.h"
+#include "net/http/http_response_headers.h"
+#include "net/http/http_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+void HeadersToRaw(std::string* headers) {
+  std::replace(headers->begin(), headers->end(), '\n', '\0');
+  if (!headers->empty())
+    *headers += '\0';
+}
+
+// Calcuates MD5 hash value for a string and then base64 encode it.
+static std::string GetEncoded(const std::string& input) {
+  base::MD5Digest digest;
+  base::MD5Sum(input.c_str(), input.size(), &digest);
+  std::string base64encoded;
+  base::Base64Encode(std::string((char*)digest.a,
+                     ARRAYSIZE_UNSAFE(digest.a)), &base64encoded);
+  return base64encoded;
+}
+
+// Replaces all contents within "[]" by corresponding base64 encoded MD5 value.
+void ReplaceWithEncodedString(std::string* input)
+{
+  size_t start, end;
+  while (true) {
+    start = input->find("[");
+    if (start == std::string::npos) break;
+    end = input->find("]", start);
+    std::string need_to_encode = input->substr(start + 1, end - start - 1);
+    *input = input->substr(0, start) + GetEncoded(need_to_encode) +
+             input->substr(end + 1);
+  }
+}
+
+// Testcase for fingerprint checking functions. |received_fingerprint| is
+// fingerprint received from the data reduction proxy. |expected_tampered| is
+// expected tampered or not result.
+struct TestCaseCheckingFingerprint {
+  std::string raw_header;
+  std::string received_fingerprint;
+  bool expected_tampered;
+};
+
+}  // namespace
+
+namespace data_reduction_proxy {
+
+class DataReductionProxyTamperDetectionTest : public testing::Test {
+ public:
+  static void TestFingerprintCommon(const TestCaseCheckingFingerprint& test,
+      DataReductionProxyTamperDetection::FingerprintCode fingerprint);
+};
+
+// Common function for testing fingerprint checking functions. For a given
+// header string |test.raw_header|, generates HttpResponseHeaders |headers| and
+// checks specified fingerprint checking function returns expected result or
+// not.
+void DataReductionProxyTamperDetectionTest::TestFingerprintCommon(
+    const TestCaseCheckingFingerprint& test,
+    DataReductionProxyTamperDetection::FingerprintCode fingerprint) {
+  std::string raw_headers(test.raw_header);
+  HeadersToRaw(&raw_headers);
+  scoped_refptr<net::HttpResponseHeaders> headers(
+      new net::HttpResponseHeaders(raw_headers));
+
+  // Removes Chrome-Proxy header's fingerprint from Chrome-Proxy header.
+  std::vector<std::string> chrome_proxy_header_values =
+      DataReductionProxyTamperDetection::
+      GetHeaderValues(headers, "Chrome-Proxy");
+
+  DataReductionProxyTamperDetection::RemoveChromeProxyFingerprint(
+      &chrome_proxy_header_values);
+
+  DataReductionProxyTamperDetection tamper_detection(
+      headers, true, 0, &chrome_proxy_header_values);
+
+  bool tampered;
+  switch (fingerprint) {
+  case DataReductionProxyTamperDetection::CHROMEPROXY:
+    tampered = tamper_detection.IsChromeProxyHeaderTampered(
+        test.received_fingerprint);
+    break;
+  case DataReductionProxyTamperDetection::VIA:
+    tampered = tamper_detection.IsViaHeaderTampered(
+        test.received_fingerprint);
+    break;
+  case DataReductionProxyTamperDetection::OTHERHEADERS:
+    tampered = tamper_detection.AreOtherHeadersTampered(
+        test.received_fingerprint);
+    break;
+  case DataReductionProxyTamperDetection::CONTENTLENGTH:
+    tampered = tamper_detection.IsContentLengthHeaderTampered(
+        test.received_fingerprint);
+    break;
+  case DataReductionProxyTamperDetection::NONEXIST:
+    break;
+  }
+
+  EXPECT_EQ(test.expected_tampered, tampered);
+}
+
+// Checks function IsChromeProxyHeaderTampered.
+TEST_F(DataReductionProxyTamperDetectionTest, ChromeProxy) {
+  TestCaseCheckingFingerprint test[] = {
+    // Checks sorting values and decoding.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,"
+      "fp=123,bbbypas=0,aaxxx=xxx,bbbloc=1\n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,fp=123,",
+      false,
+    },
+
+    // Checks Chrome-Proxy's fingerprint removing.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: a,b,c,d,e,3,2,1," +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "=1231\n",
+      "1,2,3,a,b,c,d,e,",
+      false,
+    },
+
+    // Checks no Chrome-Proxy header case (should not happen).
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Length: 12345\n",
+      "",
+      false,
+    },
+
+    // Checks empty Chrome-Proxy header case (should not happen).
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:    \n",
+      ",",
+      false,
+    },
+
+    // Checks Chrome-Proxy header with its fingerprint only case.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:    " +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "=xyz\n",
+      "",
+      false,
+    },
+
+    // Checks empty Chrome-Proxy header case, with extra ","
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:   " +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "=abcde   ,   \n",
+      "",
+      false,
+    },
+
+    // Checks empty Chrome-Proxy header, different to fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:    " +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "=xyz\n",
+      ",",
+      true,
+    },
+
+    // Chrome-Proxy header different to its fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=2,aaxxx=xxx,bbbloc=1\n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      true,
+    },
+
+    // Chrome-Proxy header different to its fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: a,aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      true,
+    },
+
+    // Chrome-Proxy header different to its fingerprint in order.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n",
+      "aaxxx=xxx,aut=aauutthh,bbbypas=0,bbbloc=1,",
+      true,
+    },
+
+    // Checks Chrome-Proxy header with extra " ".
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aut=aauutthh    ,   bbbypas=0   ,     aaxxx=xxx"
+      "              ,bbbloc=1     \n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      false
+    },
+
+    // Check Chrome-Proxy header, with extra lines and " ".
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aut=aauutthh    ,   bbbypas=0   , bbbloc=1    \n"
+      "Chrome-Proxy:    aaxxx=xxx \n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      false
+    },
+
+    // Checks Chrome-Proxy header with multiple lines.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Chrome-Proxy:bbbloc=1   \n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      false
+    },
+
+    // Checks Chrome-Proxy header with multiple lines, at different positions
+    // of the entire header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Chrome-Proxy:    bbbloc=1\n"
+      "Via: \n"
+      "Content-Length: 12345\n"
+      "fp=123    \n",
+      "aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      false
+    },
+
+    // Checks Chrome-Proxy header with multiple same values.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Chrome-Proxy:    bbbloc=1,   fp=123    \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "aaxxx=xxx,aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,fp=123,",
+      false
+    },
+
+    // Checks Chrome-Proxy header with multiple same values.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Chrome-Proxy:    bbbloc=1,   fp=123    \n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "xyn \n" +
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "aaxxx=xxx,aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,fp=123,",
+      false
+    },
+
+    // Checks Chrome-Proxy header with multiple same values, but different to
+    // fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Chrome-Proxy:    bbbloc=1\n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "aaxxx=xxx,aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      true,
+    },
+
+    // Check Chrome-Proxy header with multiple same values, but different to
+    // fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "xyn \n" +
+      "Chrome-Proxy:    bbbloc=1\n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "aaxxx=xxx,aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      true,
+    },
+
+    // Check Chrome-Proxy header with multiple lines, but different to
+    // fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Chrome-Proxy:    bbbloc=1\n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "aaxxx=xxx,aaxxx=xxx,aut=aauutthh,bbbloc=1,bbbypas=0,",
+      true,
+    },
+
+    // Checks case whose received fingerprint is empty.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Chrome-Proxy:    aut=aauutthh\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Chrome-Proxy:    bbbypas=0\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Chrome-Proxy:    bbbloc=1\n"
+      "Chrome-Proxy:     aaxxx=xxx   \n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "",
+      true,
+    },
+
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    test[i].received_fingerprint =
+        GetEncoded(test[i].received_fingerprint);
+
+    DataReductionProxyTamperDetectionTest::TestFingerprintCommon(test[i],
+        DataReductionProxyTamperDetection::CHROMEPROXY);
+  }
+}
+
+// Check function IsViaHeaderTampered.
+TEST_F(DataReductionProxyTamperDetectionTest, Via) {
+  TestCaseCheckingFingerprint test[] = {
+    // Checks the case that Chrome-Compression-Proxy occurs at the last.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via: a, b, c, 1.1 Chrome-Compression-Proxy\n",
+      "0",
+      false
+    },
+
+    // Checks when there is intermediary between the data reduction proxy and
+    // the Chromium client.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via: a, b,  c,   1.1 Chrome-Compression-Proxy,    xyz\n",
+      "0",
+      true,
+    },
+
+    // Checks the case of empty Via header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via:  \n",
+      "0",
+      false,
+    },
+
+    // Checks the case that only the data reduction proxy's Via header occurs.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via:  1.1 Chrome-Compression-Proxy    \n",
+      "0",
+      false
+    },
+
+    // Checks the case that there are " ", i.e., empty value after the data
+    // reduction proxy's Via header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via:  1.1 Chrome-Compression-Proxy  ,  , \n",
+      "0",
+      false
+    },
+
+    // Checks the case when there is no Via header
+    {
+      "HTTP/1.1    200   OK  \n",
+      "0",
+      false
+    },
+
+    // Same to above test cases, but with deprecated data reduciton proxy Via
+    // header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via: a, b, c, 1.1 Chrome Compression Proxy\n",
+      "0",
+      false
+    },
+
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via: a, b,  c,   1.1 Chrome Compression Proxy,    xyz\n",
+      "0",
+      true,
+    },
+
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via:  \n",
+      "0",
+      false,
+    },
+
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via:  1.1 Chrome Compression Proxy    \n",
+      "0",
+      false
+    },
+
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via:  1.1 Chrome Compression Proxy  ,  , \n",
+      "0",
+      false
+    },
+
+    {
+      "HTTP/1.1    200   OK  \n",
+      "0",
+      false
+    },
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    DataReductionProxyTamperDetectionTest::TestFingerprintCommon(test[i],
+        DataReductionProxyTamperDetection::VIA);
+  }
+}
+
+// Checks function AreOtherHeadersTampered.
+TEST_F(DataReductionProxyTamperDetectionTest, OtherHeaders) {
+  // For following testcases, |received_fingerprint| is not the actual
+  // fingerprint from data reduction proxy, instead, the base64 encoded field
+  // is in plain text (within "[]") and needs to be encoded first. For example,
+  // "[12345;]:content-length" needs to be encoded to
+  // "Base64Encoded(MD5(12345;)):content-length" before calling the checking
+  // function.
+  TestCaseCheckingFingerprint test[] = {
+    // Checks the case of correct fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Via:   \n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n"
+      "Content-Length: 12345\n",
+      "[1,;2,;3,;4,;5,;]:content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case of correct fingerprint.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: aaa1\n"
+      "Cache-Control: aaa2\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "ETag: aaa3\n"
+      "Connection: aaa4\n"
+      "Expires: aaa5\n"
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[aaa1,;aaa2,;aaa3,;aaa4,;aaa5,;]:content-type:cache-control:"
+      "etag:connection:expires",
+      false
+    },
+
+    // Checks the case that one header has multiple values.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Content-Type: aaa1,    bbb1, ccc1\n"
+      "Cache-Control: aaa2\n"
+      "ETag: aaa3\n"
+      "Connection: aaa4\n"
+      "Expires: aaa5\n"
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[aaa1,bbb1,ccc1,;aaa2,;aaa3,;aaa4,;aaa5,;]:"
+      "content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that one header has multiple lines.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: aaa1,   ccc1\n"
+      "Content-Type: xxx1,    bbb1, ccc1\n"
+      "Cache-Control: aaa2\n"
+      "ETag: aaa3\n"
+      "Connection: aaa4\n"
+      "Expires: aaa5\n"
+      "Via:   \n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Content-Length: 12345\n",
+      "[aaa1,bbb1,ccc1,ccc1,xxx1,;aaa2,;aaa3,;aaa4,;aaa5,;]:"
+      "content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that one header has multiple values, and such multiple
+    // lines occur at different positions.
+    {
+      "HTTP/1.1    200   OK  \n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: aaa1,   ccc1\n"
+      "Cache-Control: aaa2\n"
+      "ETag: aaa3\n"
+      "Content-Type: xxx1,    bbb1, ccc1\n"
+      "Connection: aaa4\n"
+      "Expires: aaa5\n"
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[aaa1,bbb1,ccc1,ccc1,xxx1,;aaa2,;aaa3,;aaa4,;aaa5,;]"
+      ":content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that more than one headers have multiple values.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: aaa1,   ccc1\n"
+      "Cache-Control: ccc2    , bbb2\n"
+      "ETag: aaa3\n"
+      "Content-Type: xxx1,    bbb1, ccc1\n"
+      "Connection: aaa4\n"
+      "Cache-Control: aaa2   \n"
+      "Expires: aaa5\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[aaa1,bbb1,ccc1,ccc1,xxx1,;aaa2,bbb2,ccc2,;aaa3,;aaa4,;aaa5,;]:"
+      "content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that one of the requested headers is missing (Expires).
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: aaa1,   ccc1\n"
+      "Cache-Control: ccc2    , bbb2\n"
+      "ETag: aaa3\n"
+      "Content-Type: xxx1,    bbb1, ccc1\n"
+      "Connection: aaa4\n"
+      "Cache-Control: aaa2   \n"
+      "Via:   \n"
+      "Content-Length: 12345\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n",
+      "[aaa1,bbb1,ccc1,ccc1,xxx1,;aaa2,bbb2,ccc2,;aaa3,;aaa4,;;]:"
+      "content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that more than one of the requested headers are missing.
+    // (Content-Type, Expires).
+    {
+      "HTTP/1.1    200   OK  \n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Cache-Control: ccc2    , bbb2\n"
+      "ETag: aaa3\n"
+      "Connection: aaa4\n"
+      "Cache-Control: aaa2   \n"
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[;aaa2,bbb2,ccc2,;aaa3,;aaa4,;;]:content-type:cache-control:"
+      "etag:connection:expires",
+      false
+    },
+
+    // Checks the case that all the requested headers are missing.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Via:   \n"
+      "Content-Length: 12345\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n",
+      "[;;;;;]:content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that only one header is requested.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Via:   \n"
+      "Content-Length: 12345\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n",
+      "[12345,;]:content-length",
+      false
+    },
+
+    // Checks the case that fingerprint is different to received one.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: aaa1,   ccc1\n"
+      "Cache-Control: ccc2    , bbb2\n"
+      "ETag: etag\n"
+      "Content-Type: xxx1,    bbb1, ccc1\n"
+      "Connection: aaa4\n"
+      "Cache-Control: aaa2   \n"
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[aaa1,bbb1,ccc1,ccc1,xxx1,;aaa2,bbb2,ccc2,;aaa3,;aaa4,;;]:"
+      "content-type:cache-control:etag:connection:expires",
+      true
+    },
+
+    // Checks the case that some of the requested headers have empty value
+    // (different to above header-missing case).
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type:   \n"
+      "Cache-Control: \n"
+      "ETag: \n"
+      "Connection: \n"
+      "Expires: 5\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "[,;,;,;,;5,;]:content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case that some headers are missing, some of them are of
+    // empty values (whether delimiter "," and ";" work correctly).
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Cache-Control: \n"
+      "Connection: \n"
+      "Expires: 5\n"
+      "Via: \n"
+      "Content-Length: 12345\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n",
+      "[;,;;,;5,;]:content-type:cache-control:etag:connection:expires",
+      false
+    },
+
+    // Checks the case there is no requested header (header list is empty).
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Connection: 4\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Expires: 5\n"
+      "Via:   \n"
+      "Content-Length: 12345\n",
+      "[]",
+      false
+    },
+
+    // Checks the case that there is only one requested header and it does not
+    // exist.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Chrome-Proxy: aut=aauutthh,bbbypas=0,aaxxx=xxx,bbbloc=1\n"
+      "Content-Type: 1\n"
+      "Cache-Control: 2\n"
+      "ETag: 3\n"
+      "Connection: 4\n"
+      "Expires: 5\n"
+      "Via:   \n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n" +
+      "Content-Length: 12345\n",
+      "[;]:non_exist_header",
+      false
+    },
+
+    // Checks the case that there is only one requested header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Cache-Control: \n"
+      "Connection: \n"
+      "Expires: 5\n"
+      "Via: \n"
+      "Content-Length: 12345\n" +
+      std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy) +
+      "abcde \n",
+      "[;]:content-type",
+      false
+    },
+
+    /* Lead to NOTREACHED() */
+    /*
+    // special case, if base64 decoding fails
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Cache-Control: \n"
+      "Connection: \n"
+      "Expires: 5\n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      ";:content-type",
+      true
+    },
+
+    // special case, if base64 decoding fails
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Cache-Control: \n"
+      "Connection: \n"
+      "Expires: 5\n"
+      "Via: \n"
+      "Content-Length: 12345\n",
+      "abcde:content-type:cache-control:etag:connection:expires",
+      true
+    },
+    */
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    ReplaceWithEncodedString(&(test[i].received_fingerprint));
+    DataReductionProxyTamperDetectionTest::TestFingerprintCommon(test[i],
+        DataReductionProxyTamperDetection::OTHERHEADERS);
+  }
+}
+
+// Checks function IsContentLengthTampered.
+TEST_F(DataReductionProxyTamperDetectionTest, ContentLength) {
+  TestCaseCheckingFingerprint test[] = {
+    // Checks the case fingerprint matches received response.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: 1\n"
+      "Content-Length: 12345\n",
+      "12345",
+      false,
+    },
+
+    // Checks the case that fingerprint does not match received response.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: text/html; charset=ISO-8859-4\n"
+      "Content-Length: 12345\n",
+      "125",
+      true,
+    },
+
+    // Checks the case that the data reduction proxy has not sent
+    // Content-Length header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: text/javascript\n"
+      "Content-Length: 12345\n",
+      "",
+      false,
+    },
+
+    // Checks the case that the data reduction proxy sends invalid
+    // Content-Length header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: text/javascript\n"
+      "Content-Length: 12345\n",
+      "aaa",
+      false,
+    },
+
+    // Checks the case that the data reduction proxy sends invalid
+    // Content-Length header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: text/javascript\n"
+      "Content-Length: aaa\n",
+      "aaa",
+      false,
+    },
+
+    // Checks the case that Content-Length header are missing at both end.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: 1\n",
+      "",
+      false,
+    },
+
+    // Checks the case that Content-Length is 0.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: application/x-javascript\n"
+      "Content-Length: 0\n",
+      "0",
+      false,
+    },
+
+    // Checks the case that Content-Length is empty at the data reduction proxy
+    // side.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: application/x-javascript\n"
+      "Content-Length: 123\n",
+      ",",
+      false,
+    },
+
+    // Checks the case that Content-Length header is missing at the Chromium
+    // client side.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Content-Type: application/javascript \n",
+      "123",
+      false,
+    },
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    DataReductionProxyTamperDetectionTest::TestFingerprintCommon(test[i],
+        DataReductionProxyTamperDetection::CONTENTLENGTH);
+  }
+}
+
+// Testcase for RemoveChromeProxyFingerprint function.
+TEST_F(DataReductionProxyTamperDetectionTest, HeaderRemoving) {
+  struct {
+    std::string input_values[10];
+    std::string expected_output_values[10];
+  } test[] = {
+    // Checks the case that there is no Chrome-Proxy header's fingerprint.
+    {
+      {"1", "2", "3", "5",},
+      {"1", "2", "3", "5",},
+    },
+    // Checks the case that there is Chrome-Proxy header's fingerprint.
+    {
+      {"1", "2", "3",
+          std::string(tamper_detection_fingerprint_names::
+          kFingerprintChromeProxy) + "=4", "5",},
+      {"1", "2", "3", "5",},
+    },
+    // Checks the case that there is Chrome-Proxy header's fingerprint, and it
+    // occurs at the end.
+    {
+      {"1", "2", "3",
+          std::string(tamper_detection_fingerprint_names::
+          kFingerprintChromeProxy) + "=4",},
+      {"1", "2", "3",},
+    },
+    // Checks the case that there is Chrome-Proxy header's fingerprint, and it
+    // occurs at the beginning.
+    {
+      {std::string(tamper_detection_fingerprint_names::kFingerprintChromeProxy)
+          + "=1", "2", "3",},
+      {"2", "3",},
+    },
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    std::vector<std::string> input_values, output_values;
+    for (size_t j=0; j<ARRAYSIZE_UNSAFE(test[i].input_values); ++j) {
+      if (test[i].input_values[j].size())
+        input_values.push_back(test[i].input_values[j]);
+    }
+    for (size_t j=0; j<ARRAYSIZE_UNSAFE(test[i].expected_output_values); ++j) {
+      if (test[i].expected_output_values[j].size())
+        output_values.push_back(test[i].expected_output_values[j]);
+    }
+
+    DataReductionProxyTamperDetection::RemoveChromeProxyFingerprint(
+        &input_values);
+
+    EXPECT_EQ(input_values, output_values);
+  }
+}
+
+// Testcase for ValuesToSortedString function.
+TEST_F(DataReductionProxyTamperDetectionTest, ValuesToSortedString) {
+  struct {
+    std::string input_values[10];
+    std::string expected_output_string;
+  } test[] = {
+    // Checks the correctness of sorting.
+    {
+      {"1", "2", "3",},
+      "1,2,3,",
+    },
+    // Checks the case that there is an empty input vector.
+    {
+      {},
+      "",
+    },
+    // Checks the case that there is an empty string in the input vector.
+    {
+      {" ",},
+      ",",
+    },
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    std::vector<std::string> input_values;
+    for (size_t j=0; j<ARRAYSIZE_UNSAFE(test[i].input_values); ++j) {
+      if (test[i].input_values[j].size()) {
+        if (test[i].input_values[j] == " ")
+          input_values.push_back("");
+        else
+          input_values.push_back(test[i].input_values[j]);
+      }
+    }
+
+    std::string output_string = DataReductionProxyTamperDetection::
+        ValuesToSortedString(&input_values);
+
+    EXPECT_EQ(output_string, test[i].expected_output_string);
+  }
+}
+
+// Testcase for GetHeaderValues function.
+TEST_F(DataReductionProxyTamperDetectionTest, GetHeaderValues) {
+  struct {
+    std::string raw_header;
+    std::string header_name;
+    std::string expected_output_values[10];
+  } test[] = {
+    // Checks the correctness of getting single line header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "test: 1, 2, 3\n",
+      "test",
+      {"1", "2", "3"},
+    },
+    // Checks the correctness of getting multiple lines header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "test: 1, 2, 3\n"
+      "test: 4, 5, 6\n"
+      "test: 7, 8, 9\n",
+      "test",
+      {"1", "2", "3", "4", "5", "6", "7", "8", "9"},
+    },
+    // Checks the correctness of getting missing header.
+    {
+      "HTTP/1.1    200   OK  \n",
+      "test",
+      {},
+    },
+    // Checks the correctness of getting empty header.
+    {
+      "HTTP/1.1    200   OK  \n"
+      "test:   \n",
+      "test",
+      {" "},
+    },
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    std::string raw_headers(test[i].raw_header);
+    HeadersToRaw(&raw_headers);
+    scoped_refptr<net::HttpResponseHeaders> headers =
+        new net::HttpResponseHeaders(raw_headers);
+
+    std::vector<std::string> expected_output_values;
+    for (size_t j=0; j<ARRAYSIZE_UNSAFE(test[i].expected_output_values); ++j) {
+      if ((test[i].expected_output_values[j]).size()) {
+        if (test[i].expected_output_values[j] == " ")
+          expected_output_values.push_back("");
+        else
+          expected_output_values.push_back(test[i].expected_output_values[j]);
+      }
+    }
+
+    std::vector<std::string> output_values =
+        DataReductionProxyTamperDetection::GetHeaderValues(
+        headers, test[i].header_name);
+    EXPECT_EQ(expected_output_values, output_values);
+  }
+}
+
+// Testcase for main function CheckResponseFingerprint. First generate
+// simulated response from the data reduction proxy, by replacing fingerprint
+// with its base64 encoded MD5 value and appending it to Chrome-Proxy header.
+// Then runs through function CheckResponseFingerprint.
+TEST_F(DataReductionProxyTamperDetectionTest, Completed) {
+  struct {
+    std::string raw_header;
+    std::string chrome_header;
+    bool expected_contain_tamper_detect_fingerprints;
+    bool expected_tampered_chrome_proxy;
+    bool expected_tampered_via;
+    bool expected_tampered_other_headers;
+    bool expected_tampered_content_length;
+  } test[] = {
+    // Check normal case, Chrome-Proxy fingerprint doesn't exist
+    {
+      "HTTP/1.1    200   OK  \n"
+      "Via: a1, b2, 1.1 Chrome-Compression-Proxy\n"
+      "Content-Length: 12345\n"
+      "header1: header_1\n"
+      "header2: header_2\n"
+      "header3: header_3\n",
+      "a,b,c,d,e," +
+      std::string(tamper_detection_fingerprint_names::
+          kFingerprintContentLength) + "=12345," +
+      std::string(tamper_detection_fingerprint_names::
+          kFingerprintOtherHeaders) +
+      "=[header_1,;header_2,;header_3,;]:header1:header2:header3," +
+      std::string(tamper_detection_fingerprint_names::kFingerprintVia) + "=0,",
+      true,
+      false,
+      false,
+      false,
+      false,
+    },
+  };
+
+  for (size_t i=0; i<ARRAYSIZE_UNSAFE(test); ++i) {
+    // Replace fingerprint with base64 encoded MD5 value.
+    ReplaceWithEncodedString(&(test[i].chrome_header));
+    // Generate fingerprint for Chrome-Proxy header.
+    std::string chrome_header_fingerprint = GetEncoded(test[i].chrome_header);
+    // Append Chrome-Proxy header to response headers.
+    test[i].raw_header += "Chrome-Proxy: " + test[i].chrome_header +
+        std::string(tamper_detection_fingerprint_names::
+        kFingerprintChromeProxy) + "=" + chrome_header_fingerprint + "\n";
+
+    std::string raw_headers(test[i].raw_header);
+    HeadersToRaw(&raw_headers);
+    scoped_refptr<net::HttpResponseHeaders> headers =
+        new net::HttpResponseHeaders(raw_headers);
+
+    // Below copying codes from CheckResponseFingerprint, with checking points
+    // added.
+    std::string chrome_proxy_fingerprint;
+    bool contain_chrome_proxy_fingerprint = GetDataReductionProxyActionValue(
+        headers,
+        tamper_detection_fingerprint_names::kFingerprintChromeProxy,
+        &chrome_proxy_fingerprint);
+
+
+    EXPECT_EQ(test[i].expected_contain_tamper_detect_fingerprints,
+              contain_chrome_proxy_fingerprint);
+    if (!contain_chrome_proxy_fingerprint)
+      return;
+    std::vector<std::string> chrome_proxy_header_values =
+        DataReductionProxyTamperDetection::
+        GetHeaderValues(headers, "Chrome-Proxy");
+
+    DataReductionProxyTamperDetection::
+        RemoveChromeProxyFingerprint(&chrome_proxy_header_values);
+
+    DataReductionProxyTamperDetection tamper_detection(
+        headers,
+        true,
+        0,
+        &chrome_proxy_header_values);
+
+    bool tampered_chrome_proxy =
+        tamper_detection.IsChromeProxyHeaderTampered(chrome_proxy_fingerprint);
+    EXPECT_EQ(test[i].expected_tampered_chrome_proxy, tampered_chrome_proxy);
+    if (tampered_chrome_proxy)
+      return;
+
+    // Checks other fingerprints.
+    const char* fingerprint_names[] = {
+      data_reduction_proxy::tamper_detection_fingerprint_names::
+          kFingerprintVia,
+      data_reduction_proxy::tamper_detection_fingerprint_names::
+          kFingerprintOtherHeaders,
+      data_reduction_proxy::tamper_detection_fingerprint_names::
+          kFingerprintContentLength
+    };
+
+    for (size_t j = 0; j < ARRAYSIZE_UNSAFE(fingerprint_names); ++j) {
+      std::string fingerprint;
+      if (!GetDataReductionProxyActionValue(
+          headers, fingerprint_names[j], &fingerprint)) {
+        continue;
+      }
+
+      bool tampered = false;
+      DataReductionProxyTamperDetection::FingerprintCode fingerprint_code =
+          tamper_detection.GetFingerprintCode(fingerprint_names[i]);
+      switch (fingerprint_code) {
+      case DataReductionProxyTamperDetection::VIA:
+        tampered = tamper_detection.IsViaHeaderTampered(fingerprint);
+        EXPECT_EQ(test[i].expected_tampered_via, tampered);
+        break;
+      case DataReductionProxyTamperDetection::OTHERHEADERS:
+        tampered = tamper_detection.AreOtherHeadersTampered(fingerprint);
+        EXPECT_EQ(test[i].expected_tampered_other_headers, tampered);
+        break;
+      case DataReductionProxyTamperDetection::CONTENTLENGTH:
+        tampered = tamper_detection.IsContentLengthHeaderTampered(fingerprint);
+        EXPECT_EQ(test[i].expected_tampered_content_length, tampered);
+        break;
+      default:
+        NOTREACHED();
+        break;
+      }
+    }
+    return;
+  }
+}
+
+} // namespace