From 5bc745fcba8fbfa1b0cda45f28173b8e7bec1d45 Mon Sep 17 00:00:00 2001
From: "antrim@chromium.org"
 <antrim@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Wed, 26 Mar 2014 00:37:42 +0000
Subject: [PATCH] Impelent signature generation for supervised user passwords.

TBR=stevenjb@chromium.org
for chromeos/chromeos.gyp

BUG=244472

Review URL: https://codereview.chromium.org/209433007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@259419 0039d316-1c4b-4281-b951-d872f2087c98
---
 .../managed/supervised_user_authentication.cc      | 30 +++++++++++++++++++---
 chrome/chrome_browser_chromeos.gypi                |  2 ++
 chromeos/chromeos.gyp                              | 14 ++++++++++
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/chrome/browser/chromeos/login/managed/supervised_user_authentication.cc b/chrome/browser/chromeos/login/managed/supervised_user_authentication.cc
index 0e3307c35f7f..a9b92cbd1a4e 100644
--- a/chrome/browser/chromeos/login/managed/supervised_user_authentication.cc
+++ b/chrome/browser/chromeos/login/managed/supervised_user_authentication.cc
@@ -17,7 +17,9 @@
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chromeos/chromeos_switches.h"
+#include "chromeos/cryptohome/signed_secret.pb.h"
 #include "content/public/browser/browser_thread.h"
+#include "crypto/hmac.h"
 #include "crypto/random.h"
 #include "crypto/symmetric_key.h"
 
@@ -28,11 +30,15 @@ namespace {
 // Byte size of hash salt.
 const unsigned kSaltSize = 32;
 
-// Parameters of cryptographic hashing.
+// Parameters of cryptographic hashing for new user schema.
 const unsigned kNumIterations = 1234;
 const unsigned kKeySizeInBits = 256;
 
+// Size of key signature.
 const unsigned kHMACKeySizeInBits = 256;
+const int kSignatureLength = 32;
+
+// Size of master key (in bytes).
 const int kMasterKeySize = 32;
 
 std::string CreateSalt() {
@@ -69,8 +75,26 @@ std::string BuildRawHMACKey() {
 std::string BuildPasswordSignature(const std::string& password,
                                    int revision,
                                    const std::string& base64_signature_key) {
-  std::string raw_result, result;
-  // TODO(antrim) : implement signature as soon as wad@ lands sample code.
+  ac::chrome::managedaccounts::account::Secret secret;
+  secret.set_revision(revision);
+  secret.set_secret(password);
+  std::string buffer;
+  if (!secret.SerializeToString(&buffer))
+    LOG(FATAL) << "Protobuf::SerializeToString failed";
+  std::string signature_key;
+  base::Base64Decode(base64_signature_key, &signature_key);
+
+  crypto::HMAC hmac(crypto::HMAC::SHA256);
+  if (!hmac.Init(signature_key))
+    LOG(FATAL) << "HMAC::Init failed";
+
+  unsigned char out_bytes[kSignatureLength];
+  if (!hmac.Sign(buffer, out_bytes, sizeof(out_bytes)))
+    LOG(FATAL) << "HMAC::Sign failed";
+
+  std::string raw_result(out_bytes, out_bytes + sizeof(out_bytes));
+
+  std::string result;
   base::Base64Encode(raw_result, &result);
   return result;
 }
diff --git a/chrome/chrome_browser_chromeos.gypi b/chrome/chrome_browser_chromeos.gypi
index 063dbe3b673e..9e52737a194f 100644
--- a/chrome/chrome_browser_chromeos.gypi
+++ b/chrome/chrome_browser_chromeos.gypi
@@ -46,6 +46,8 @@
         '../build/linux/system.gyp:dbus',
         '../chromeos/chromeos.gyp:chromeos',
         '../chromeos/chromeos.gyp:chromeos_memory',
+        # browser_chromeos #includes signed_secret.pb.h directly.
+        '../chromeos/chromeos.gyp:cryptohome_signkey_proto',
         # browser_chromeos #includes power_supply_properties.pb.h directly.
         '../chromeos/chromeos.gyp:power_manager_proto',
         '../chromeos/ime/input_method.gyp:gencode',
diff --git a/chromeos/chromeos.gyp b/chromeos/chromeos.gyp
index f54da868b05a..311501466b39 100644
--- a/chromeos/chromeos.gyp
+++ b/chromeos/chromeos.gyp
@@ -559,5 +559,19 @@
       },
       'includes': ['../build/protoc.gypi'],
     },
+    {
+      # Protobuf compiler/generator for cryptohome key signing protocol buffer.
+      'target_name': 'cryptohome_signkey_proto',
+      'type': 'static_library',
+      'sources': [
+        '../third_party/cros_system_api/dbus/cryptohome/signed_secret.proto',
+      ],
+      'variables': {
+        'proto_in_dir': '../third_party/cros_system_api/dbus/cryptohome',
+        'proto_out_dir': 'chromeos/cryptohome',
+      },
+      'includes': ['../build/protoc.gypi'],
+    },
+
   ],
 }
-- 
2.11.4.GIT