Move the Nigori classes from base to sync.

BUG=none
TEST=NigoriTest

Review URL: http://codereview.chromium.org/1549012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43366 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 411 insertions, 1 deletions

diff --git a/chrome/browser/sync/util/nigori.cc b/chrome/browser/sync/util/nigori.cc
new file mode 100644
index 0000000..b954418
--- /dev/null
+++ b/chrome/browser/sync/util/nigori.cc
@@ -0,0 +1,228 @@
+// Copyright (c) 2010 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 "chrome/browser/sync/util/nigori.h"
+
+#if defined(OS_WIN)
+#include <winsock2.h>  // for htonl
+#endif
+
+#include <sstream>
+#include <vector>
+
+#include "base/base64.h"
+#include "base/crypto/encryptor.h"
+#include "base/hmac.h"
+#include "base/logging.h"
+#include "base/rand_util.h"
+#include "base/string_util.h"
+
+using base::Base64Encode;
+using base::Base64Decode;
+using base::Encryptor;
+using base::HMAC;
+using base::RandInt;
+using base::SymmetricKey;
+
+namespace browser_sync {
+
+// NigoriStream simplifies the concatenation operation of the Nigori protocol.
+class NigoriStream {
+ public:
+  // Append the big-endian representation of the length of |value| with 32 bits,
+  // followed by |value| itself to the stream.
+  NigoriStream& operator<<(const std::string& value) {
+    uint32 size = htonl(value.size());
+    stream_.write((char *) &size, sizeof(uint32));
+    stream_ << value;
+    return *this;
+  }
+
+  // Append the big-endian representation of the length of |type| with 32 bits,
+  // followed by the big-endian representation of the value of |type|, with 32
+  // bits, to the stream.
+  NigoriStream& operator<<(const Nigori::Type type) {
+    uint32 size = htonl(sizeof(uint32));
+    stream_.write((char *) &size, sizeof(uint32));
+    uint32 value = htonl(type);
+    stream_.write((char *) &value, sizeof(uint32));
+    return *this;
+  }
+
+  std::string str() {
+    return stream_.str();
+  }
+
+ private:
+  std::ostringstream stream_;
+};
+
+// static
+const char Nigori::kSaltSalt[] = "saltsalt";
+
+Nigori::Nigori(const std::string& hostname)
+    : hostname_(hostname) {
+}
+
+Nigori::~Nigori() {
+}
+
+bool Nigori::Init(const std::string& username, const std::string& password) {
+  NigoriStream salt_password;
+  salt_password << username << hostname_;
+
+  // Suser = PBKDF2(Username || Servername, "saltsalt", Nsalt, 8)
+  scoped_ptr<SymmetricKey> user_salt(SymmetricKey::DeriveKeyFromPassword(
+      SymmetricKey::HMAC_SHA1, salt_password.str(),
+      kSaltSalt,
+      kSaltIterations,
+      kSaltKeySize));
+  DCHECK(user_salt.get());
+
+  std::string raw_user_salt;
+  user_salt->GetRawKey(&raw_user_salt);
+
+  // Kuser = PBKDF2(P, Suser, Nuser, 16)
+  user_key_.reset(SymmetricKey::DeriveKeyFromPassword(SymmetricKey::AES,
+      password, raw_user_salt, kUserIterations, kDerivedKeySizeInBits));
+  DCHECK(user_key_.get());
+
+  // Kenc = PBKDF2(P, Suser, Nenc, 16)
+  encryption_key_.reset(SymmetricKey::DeriveKeyFromPassword(SymmetricKey::AES,
+      password, raw_user_salt, kEncryptionIterations, kDerivedKeySizeInBits));
+  DCHECK(encryption_key_.get());
+
+  // Kmac = PBKDF2(P, Suser, Nmac, 16)
+  mac_key_.reset(SymmetricKey::DeriveKeyFromPassword(
+      SymmetricKey::HMAC_SHA1, password, raw_user_salt, kSigningIterations,
+      kDerivedKeySizeInBits));
+  DCHECK(mac_key_.get());
+
+  return true;
+}
+
+// Permute[Kenc,Kmac](type || name)
+bool Nigori::Permute(Type type, const std::string& name,
+                     std::string* permuted) {
+  DCHECK_LT(0U, name.size());
+
+  NigoriStream plaintext;
+  plaintext << type << name;
+
+  Encryptor encryptor;
+  if (!encryptor.Init(encryption_key_.get(), Encryptor::CBC,
+                      std::string(kIvSize, 0)))
+    return false;
+
+  std::string ciphertext;
+  if (!encryptor.Encrypt(plaintext.str(), &ciphertext))
+    return false;
+
+  std::string raw_mac_key;
+  if (!mac_key_->GetRawKey(&raw_mac_key))
+    return false;
+
+  HMAC hmac(HMAC::SHA256);
+  if (!hmac.Init(raw_mac_key))
+    return false;
+
+  std::vector<unsigned char> hash(kHashSize);
+  if (!hmac.Sign(ciphertext, &hash[0], hash.size()))
+    return false;
+
+  std::string output;
+  output.assign(ciphertext);
+  output.append(hash.begin(), hash.end());
+
+  return Base64Encode(output, permuted);
+}
+
+std::string GenerateRandomString(size_t size) {
+  // TODO(albertb): Use a secure random function.
+  std::string random(size, 0);
+  for (size_t i = 0; i < size; ++i)
+    random[i] = RandInt(0, 0xff);
+  return random;
+}
+
+// Enc[Kenc,Kmac](value)
+bool Nigori::Encrypt(const std::string& value, std::string* encrypted) {
+  DCHECK_LT(0U, value.size());
+
+  std::string iv = GenerateRandomString(kIvSize);
+
+  Encryptor encryptor;
+  if (!encryptor.Init(encryption_key_.get(), Encryptor::CBC, iv))
+    return false;
+
+  std::string ciphertext;
+  if (!encryptor.Encrypt(value, &ciphertext))
+    return false;
+
+  std::string raw_mac_key;
+  if (!mac_key_->GetRawKey(&raw_mac_key))
+    return false;
+
+  HMAC hmac(HMAC::SHA256);
+  if (!hmac.Init(raw_mac_key))
+    return false;
+
+  std::vector<unsigned char> hash(kHashSize);
+  if (!hmac.Sign(ciphertext, &hash[0], hash.size()))
+    return false;
+
+  std::string output;
+  output.assign(iv);
+  output.append(ciphertext);
+  output.append(hash.begin(), hash.end());
+
+  return Base64Encode(output, encrypted);
+}
+
+bool Nigori::Decrypt(const std::string& encrypted, std::string* value) {
+  std::string input;
+  if (!Base64Decode(encrypted, &input))
+    return false;
+
+  if (input.size() < kIvSize * 2 + kHashSize)
+    return false;
+
+  // The input is:
+  // * iv (16 bytes)
+  // * ciphertext (multiple of 16 bytes)
+  // * hash (32 bytes)
+  std::string iv(input.substr(0, kIvSize));
+  std::string ciphertext(input.substr(kIvSize,
+                                      input.size() - (kIvSize + kHashSize)));
+  std::string hash(input.substr(input.size() - kHashSize, kHashSize));
+
+  std::string raw_mac_key;
+  if (!mac_key_->GetRawKey(&raw_mac_key))
+    return false;
+
+  HMAC hmac(HMAC::SHA256);
+  if (!hmac.Init(raw_mac_key))
+    return false;
+
+  std::vector<unsigned char> expected(kHashSize);
+  if (!hmac.Sign(ciphertext, &expected[0], expected.size()))
+    return false;
+
+  if (hash.compare(0, hash.size(),
+                   reinterpret_cast<char *>(&expected[0]),
+                   expected.size()))
+    return false;
+
+  Encryptor encryptor;
+  if (!encryptor.Init(encryption_key_.get(), Encryptor::CBC, iv))
+    return false;
+
+  std::string plaintext;
+  if (!encryptor.Decrypt(ciphertext, value))
+    return false;
+
+  return true;
+}
+
+}  // namespace browser_sync
diff --git a/chrome/browser/sync/util/nigori.h b/chrome/browser/sync/util/nigori.h
new file mode 100644
index 0000000..67dc758
--- /dev/null
+++ b/chrome/browser/sync/util/nigori.h
@@ -0,0 +1,72 @@
+// Copyright (c) 2010 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.
+
+#ifndef CHROME_BROWSER_SYNC_UTIL_NIGORI_H_
+#define CHROME_BROWSER_SYNC_UTIL_NIGORI_H_
+
+#include <string>
+
+#include "base/crypto/symmetric_key.h"
+#include "base/scoped_ptr.h"
+
+namespace browser_sync {
+
+// A (partial) implementation of Nigori, a protocol to securely store secrets in
+// the cloud. This implementation does not support server authentication or
+// assisted key derivation.
+//
+// To store secrets securely, use the |Permute| method to derive a lookup name
+// for your secret (basically a map key), and |Encrypt| and |Decrypt| to store
+// and retrieve the secret.
+//
+// TODO: Link to doc.
+class Nigori {
+ public:
+  enum Type {
+    Password = 1,
+  };
+
+  // Creates a Nigori client for communicating with |hostname|. Note that
+  // |hostname| is used to derive the keys used to encrypt and decrypt data.
+  explicit Nigori(const std::string& hostname);
+  virtual ~Nigori();
+
+  // Initialize the client with the supplied |username| and |password|.
+  bool Init(const std::string& username, const std::string& password);
+
+  // Derives a secure lookup name from |type| and |name|. If |hostname|,
+  // |username| and |password| are kept constant, a given |type| and |name| pair
+  // always yields the same |permuted| value. Note that |permuted| will be
+  // Base64 encoded.
+  bool Permute(Type type, const std::string& name, std::string* permuted);
+
+  // Encrypts |value|. Note that on success, |encrypted| will be Base64
+  // encoded.
+  bool Encrypt(const std::string& value, std::string* encrypted);
+
+  // Decrypts |value| into |decrypted|. It is assumed that |value| is Base64
+  // encoded.
+  bool Decrypt(const std::string& value, std::string* decrypted);
+
+  static const char kSaltSalt[];  // The salt used to derive the user salt.
+  static const size_t kSaltKeySize = 8;
+  static const size_t kDerivedKeySizeInBits = 128;
+  static const size_t kIvSize = 16;
+  static const size_t kHashSize = 32;
+
+  static const size_t kSaltIterations = 1001;
+  static const size_t kUserIterations = 1002;
+  static const size_t kEncryptionIterations = 1003;
+  static const size_t kSigningIterations = 1004;
+
+ private:
+  const std::string hostname_;
+  scoped_ptr<base::SymmetricKey> user_key_;
+  scoped_ptr<base::SymmetricKey> encryption_key_;
+  scoped_ptr<base::SymmetricKey> mac_key_;
+};
+
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_UTIL_NIGORI_H_
diff --git a/chrome/browser/sync/util/nigori_unittest.cc b/chrome/browser/sync/util/nigori_unittest.cc
new file mode 100644
index 0000000..f01d015
--- /dev/null
+++ b/chrome/browser/sync/util/nigori_unittest.cc
@@ -0,0 +1,105 @@
+// Copyright (c) 2010 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 "chrome/browser/sync/util/nigori.h"
+
+#include <string>
+
+#include "base/scoped_ptr.h"
+#include "base/string_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+#if defined(USE_NSS)
+#define MAYBE(name) name
+#else
+#define MAYBE(name) DISABLED_ ## name
+#endif
+
+TEST(NigoriTest, MAYBE(PermuteIsConstant)) {
+  browser_sync::Nigori nigori1("example.com");
+  EXPECT_TRUE(nigori1.Init("username", "password"));
+
+  std::string permuted1;
+  EXPECT_TRUE(nigori1.Permute(browser_sync::Nigori::Password,
+                              "name",
+                              &permuted1));
+
+  browser_sync::Nigori nigori2("example.com");
+  EXPECT_TRUE(nigori2.Init("username", "password"));
+
+  std::string permuted2;
+  EXPECT_TRUE(nigori2.Permute(browser_sync::Nigori::Password,
+                              "name",
+                              &permuted2));
+
+  EXPECT_LT(0U, permuted1.size());
+  EXPECT_EQ(permuted1, permuted2);
+}
+
+TEST(NigoriTest, MAYBE(EncryptDifferentIv)) {
+  browser_sync::Nigori nigori("example.com");
+  EXPECT_TRUE(nigori.Init("username", "password"));
+
+  std::string plaintext("value");
+
+  std::string encrypted1;
+  EXPECT_TRUE(nigori.Encrypt(plaintext, &encrypted1));
+
+  std::string encrypted2;
+  EXPECT_TRUE(nigori.Encrypt(plaintext, &encrypted2));
+
+  EXPECT_NE(encrypted1, encrypted2);
+}
+
+TEST(NigoriTest, MAYBE(EncryptDecrypt)) {
+  browser_sync::Nigori nigori("example.com");
+  EXPECT_TRUE(nigori.Init("username", "password"));
+
+  std::string plaintext("value");
+
+  std::string encrypted;
+  EXPECT_TRUE(nigori.Encrypt(plaintext, &encrypted));
+
+  std::string decrypted;
+  EXPECT_TRUE(nigori.Decrypt(encrypted, &decrypted));
+
+  EXPECT_EQ(plaintext, decrypted);
+}
+
+TEST(NigoriTest, MAYBE(CorruptedIv)) {
+  browser_sync::Nigori nigori("example.com");
+  EXPECT_TRUE(nigori.Init("username", "password"));
+
+  std::string plaintext("test");
+
+  std::string encrypted;
+  EXPECT_TRUE(nigori.Encrypt(plaintext, &encrypted));
+
+  // Corrupt the IV by changing one of its byte.
+  encrypted[0] = (encrypted[0] == 'a' ? 'b' : 'a');
+
+  std::string decrypted;
+  EXPECT_TRUE(nigori.Decrypt(encrypted, &decrypted));
+
+  EXPECT_NE(plaintext, decrypted);
+}
+
+TEST(NigoriTest, MAYBE(CorruptedCiphertext)) {
+  browser_sync::Nigori nigori("example.com");
+  EXPECT_TRUE(nigori.Init("username", "password"));
+
+  std::string plaintext("test");
+
+  std::string encrypted;
+  EXPECT_TRUE(nigori.Encrypt(plaintext, &encrypted));
+
+  // Corrput the ciphertext by changing one of its bytes.
+  encrypted[browser_sync::Nigori::kIvSize + 10] =
+      (encrypted[browser_sync::Nigori::kIvSize + 10] == 'a' ? 'b' : 'a');
+
+  std::string decrypted;
+  EXPECT_FALSE(nigori.Decrypt(encrypted, &decrypted));
+
+  EXPECT_NE(plaintext, decrypted);
+}
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index e775c50..3c2b6b9 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -961,6 +961,8 @@
         'browser/sync/util/extensions_activity_monitor.cc',
         'browser/sync/util/extensions_activity_monitor.h',
         'browser/sync/util/fast_dump.h',
+        'browser/sync/util/nigori.cc',
+        'browser/sync/util/nigori.h',
         'browser/sync/util/row_iterator.h',
         'browser/sync/util/signin.h',
         'browser/sync/util/sync_types.h',
@@ -992,7 +994,8 @@
         }],
         ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"', {
           'dependencies': [
-            '../build/linux/system.gyp:gtk'
+            '../build/linux/system.gyp:gtk',
+            '../build/linux/system.gyp:nss'
           ],
           'link_settings': {
             'libraries': [
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 07a8207..c5ac745 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1638,6 +1638,7 @@
         'browser/sync/util/crypto_helpers_unittest.cc',
         'browser/sync/util/event_sys_unittest.cc',
         'browser/sync/util/extensions_activity_monitor_unittest.cc',
+        'browser/sync/util/nigori_unittest.cc',
         'browser/sync/util/user_settings_unittest.cc',
         'test/file_test_utils.cc',
         'test/sync/engine/mock_gaia_authenticator.cc',
@@ -1704,6 +1705,7 @@
         ['OS=="linux"', {
           'dependencies': [
             '../build/linux/system.gyp:gtk',
+            '../build/linux/system.gyp:nss',
             'packed_resources'
           ],
         }],