[Win] Add option to reauthenticate the OS user before revealing passwords.

chrome/browser/password_manager/password_manager_util_win.cc

+// Copyright (c) 2013 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.
+
+// windows.h must be first otherwise Win8 SDK breaks.
+#include <windows.h>
+#include <ntsecapi.h>
+#include <wincred.h>
+#include <subauth.h>
+
+// SECURITY_WIN32 must be defined in order to get
+// EXTENDED_NAME_FORMAT enumeration.
+#define SECURITY_WIN32 1
+#include <security.h>
+#undef SECURITY_WIN32
+
+#include "base/strings/utf_string_conversions.h"
+#include "grit/chromium_strings.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+
+namespace password_manager_util {
+
+// http://msdn.microsoft.com/en-us/library/cc245617.aspx.
+#define SAM_USERALLINFORMATION 21
+
+// http://msdn.microsoft.com/en-us/library/cc245522.aspx.
+#define DOMAIN_READ 0x00020084
+#define DOMAIN_LOOKUP 0x00000200
+
+const unsigned kMaxPasswordRetries = 3;
+const unsigned kCredUiDefaultFlags =
+    CREDUI_FLAGS_GENERIC_CREDENTIALS |
+    CREDUI_FLAGS_EXCLUDE_CERTIFICATES |
+    CREDUI_FLAGS_KEEP_USERNAME |
+    CREDUI_FLAGS_ALWAYS_SHOW_UI |
+    CREDUI_FLAGS_DO_NOT_PERSIST;
+
+// http://msdn.microsoft.com/en-us/library/cc245753.aspx.
+typedef NTSTATUS (WINAPI *SamConnectPtr)(PUNICODE_STRING ServerName,
+                                         PSAM_HANDLE ServerHandle,
+                                         DWORD DesiredAccess,
+                                         PVOID);
+
+// http://msdn.microsoft.com/en-us/library/cc245748.aspx.
+typedef NTSTATUS (WINAPI *SamOpenDomainPtr)(SAM_HANDLE ServerHandle,
+                                            DWORD dwAccess,
+                                            PSID DomainId,
+                                            PSAM_HANDLE DomainHandle);
+
+// http://msdn.microsoft.com/en-us/library/cc245712.aspx.
+typedef NTSTATUS (WINAPI *SamLookupNamesInDomainPtr)(SAM_HANDLE DomainHandle,
+                                                     ULONG Count,
+                                                     PUNICODE_STRING Names,
+                                                     PULONG* RelativeIds,
+                                                     PULONG* Use);
+
+// http://msdn.microsoft.com/en-us/library/cc245752.aspx.
+typedef NTSTATUS (WINAPI *SamOpenUserPtr)(SAM_HANDLE DomainHandle,
+                                          DWORD dwAccess,
+                                          DWORD UserId,
+                                          PSAM_HANDLE UserHandle);
+
+// http://msdn.microsoft.com/en-us/library/cc245786.aspx.
+typedef NTSTATUS (WINAPI *SamQueryInformationUserPtr)(
+    SAM_HANDLE UserHandle,
+    DWORD UserInformationClass,
+    PVOID Buffer);
+
+// http://msdn.microsoft.com/en-us/library/cc245722.aspx.
+typedef NTSTATUS (WINAPI *SamCloseHandlePtr)(PSAM_HANDLE SamHandle);
+typedef NTSTATUS (WINAPI *SamFreeMemoryPtr)(PVOID Buffer);
+
+static bool checkBlankPassword(WCHAR* pUsername) {
+  SAM_HANDLE handleSam = INVALID_HANDLE_VALUE;
+  HMODULE samlibDll = LoadLibrary(L"samlib.dll");

[cpu_(ooo_6.6-7.5), 2013/10/25 17:04:43]

you are loading the library in the UI thread?

+  SAM_HANDLE handleDomain = NULL;
+  SAM_HANDLE handleUser = NULL;
+  UNICODE_STRING username = {wcslen(pUsername) * sizeof(WCHAR),
+                             wcslen(pUsername) * sizeof(WCHAR),
+                             pUsername};
+  bool hasBlankPassword = false;
+
+  if (samlibDll) {
+    SamConnectPtr sam_connect_func =
+        reinterpret_cast<SamConnectPtr>(
+            GetProcAddress(samlibDll,"SamConnect"));
+    SamOpenDomainPtr sam_open_domain_func =
+        reinterpret_cast<SamOpenDomainPtr>(
+            GetProcAddress(samlibDll,"SamOpenDomain"));
+    SamLookupNamesInDomainPtr sam_lookup_names_in_domain_func =
+        reinterpret_cast<SamLookupNamesInDomainPtr>(
+            GetProcAddress(samlibDll,"SamLookupNamesInDomain"));
+    SamOpenUserPtr sam_open_user_func =
+        reinterpret_cast<SamOpenUserPtr>(
+            GetProcAddress(samlibDll,"SamOpenUser"));
+    SamQueryInformationUserPtr sam_query_information_user_func =
+        reinterpret_cast<SamQueryInformationUserPtr>(
+            GetProcAddress(samlibDll,"SamQueryInformationUser"));
+    SamCloseHandlePtr sam_close_handle_func =
+        reinterpret_cast<SamCloseHandlePtr>(
+            GetProcAddress(samlibDll,"SamCloseHandle"));
+    SamFreeMemoryPtr sam_free_memory_func =
+        reinterpret_cast<SamFreeMemoryPtr>(
+            GetProcAddress(samlibDll,"SamFreeMemory"));
+
+    if ((sam_connect_func == NULL) ||
+        (sam_open_domain_func == NULL) ||
+        (sam_lookup_names_in_domain_func == NULL) ||
+        (sam_open_user_func == NULL) ||
+        (sam_query_information_user_func == NULL) ||
+        (sam_close_handle_func == NULL) ||
+        (sam_free_memory_func == NULL))
+    {
+      FreeLibrary(samlibDll);
+      return false;
+    }
+
+    LSA_OBJECT_ATTRIBUTES connectionAttrib = {};
+    LSA_HANDLE handlePolicy = NULL;
+
+    // http://msdn2.microsoft.com/en-us/library/ms721895(VS.85).aspx
+    PPOLICY_ACCOUNT_DOMAIN_INFO structInfoPolicy;
+
+    connectionAttrib.Length = sizeof(LSA_OBJECT_ATTRIBUTES);
+
+    NTSTATUS retval = LsaOpenPolicy(NULL,
+                                    &connectionAttrib,
+                                    POLICY_VIEW_LOCAL_INFORMATION,
+                                    &handlePolicy);
+
+    if (retval == STATUS_SUCCESS) {
+      // http://msdn.microsoft.com/en-us/library/aa378313(VS.85).aspx
+      retval = LsaQueryInformationPolicy(handlePolicy,
+                                         PolicyAccountDomainInformation,
+                                         reinterpret_cast<PVOID*>(
+                                             &structInfoPolicy));
+
+      if (retval == STATUS_SUCCESS) {
+        // http://msdn.microsoft.com/en-us/library/cc245753.aspx
+        retval = sam_connect_func(NULL, &handleSam, MAXIMUM_ALLOWED, NULL);
+
+        if (retval == STATUS_SUCCESS) {
+          // http://msdn.microsoft.com/en-us/library/cc245748.aspx
+          retval = sam_open_domain_func(handleSam,
+                                        DOMAIN_READ | DOMAIN_LOOKUP,
+                                        structInfoPolicy->DomainSid,
+                                        &handleDomain);
+
+          if (retval == STATUS_SUCCESS) {
+            PULONG relativeIds = NULL;
+            PULONG use = NULL;
+            // Get the RID for the given user name.
+            // http://msdn.microsoft.com/en-us/library/cc245712.aspx.
+            retval = sam_lookup_names_in_domain_func(handleDomain,
+                                                     1,
+                                                     &username,
+                                                     &relativeIds,
+                                                     &use);
+            if (retval == STATUS_SUCCESS) {
+              PUSER_ALL_INFORMATION ptrUserInfo = NULL;
+              // http://msdn.microsoft.com/en-us/library/cc245752.aspx
+              retval = sam_open_user_func(handleDomain,
+                                          GENERIC_READ,
+                                          relativeIds[0],
+                                          &handleUser);
+
+              if (retval == STATUS_SUCCESS) {
+                // http://msdn.microsoft.com/en-us/library/cc245786.aspx
+                retval = sam_query_information_user_func(handleUser,
+                                                         SAM_USERALLINFORMATION,
+                                                         &ptrUserInfo);
+                if (retval == STATUS_SUCCESS) {
+                  // If either the dBCSPwd attribute or the unicodePwd
+                  // attribute does not have a value, or if either of these is
+                  // equal to the respective hash of a zero-length string,
+                  // PasswordCanChange MUST be 0.
+                  // http://msdn.microsoft.com/en-us/library/cc245738.aspx
+                  if (ptrUserInfo->PasswordCanChange.HighPart == 0 &&
+                      ptrUserInfo->PasswordCanChange.LowPart == 0 ) {
+                    hasBlankPassword = true;
+                  }
+                  sam_free_memory_func(ptrUserInfo);
+                }
+                // http://msdn.microsoft.com/en-us/library/cc245722.aspx
+                sam_close_handle_func(&handleUser);
+              }
+            }
+          }
+        }
+        LsaFreeMemory(structInfoPolicy);
+      }
+      LsaClose(handlePolicy);
+    }
+    FreeLibrary(samlibDll);
+  }
+  return hasBlankPassword;
+}
+
+
+bool AuthenticateUser() {
+  bool retval = false;
+  CREDUI_INFO cui = {};
+  WCHAR username[CREDUI_MAX_USERNAME_LENGTH+1] = {};
+  WCHAR displayname[CREDUI_MAX_USERNAME_LENGTH+1] = {};
+  WCHAR password[CREDUI_MAX_PASSWORD_LENGTH+1] = {};
+  DWORD username_length = CREDUI_MAX_USERNAME_LENGTH;
+  std::wstring product_name =
+      UTF16ToWide(l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
+  std::wstring password_prompt =
+      UTF16ToWide(l10n_util::GetStringUTF16(
+                  IDS_PASSWORDS_PAGE_AUTHENTICATION_PROMPT));
+  HANDLE handle = INVALID_HANDLE_VALUE;
+  int tries = 0;
+  bool use_displayname = false;
+  bool use_principalname = false;
+  DWORD logon_result = 0;
+
+  // On a domain, we obtain the User Principal Name
+  // for domain authentication.
+  if (GetUserNameEx(NameUserPrincipal, username, &username_length)) {
+    use_principalname = true;
+  } else {
+    username_length = CREDUI_MAX_USERNAME_LENGTH;
+    // Otherwise, we're a workstation, use the plain local username.
+    if (!GetUserName(username, &username_length)) {
+      DLOG(ERROR) << "Unable to obtain username " << GetLastError();
+      return false;
+    } else {
+      // As we are on a workstation, it's possible the user
+      // has no password, so check here.
+      if (checkBlankPassword(username)) {
+        return true;
+      }
+    }
+  }
+
+  // Try and obtain a friendly display name.
+  username_length = CREDUI_MAX_USERNAME_LENGTH;
+  if (GetUserNameEx(NameDisplay, displayname, &username_length)) {
+    use_displayname = true;
+  }
+
+  cui.cbSize = sizeof(CREDUI_INFO);
+  cui.hwndParent = NULL;
+  cui.pszMessageText = password_prompt.c_str();
+  cui.pszCaptionText = product_name.c_str();
+
+  cui.hbmBanner = NULL;
+  BOOL save_password = FALSE;
+  DWORD credErr = NO_ERROR;
+
+  do {
+    tries++;
+
+    // TODO(wfh) Make sure we support smart cards here.
+    credErr = CredUIPromptForCredentials(
+                  &cui,
+                  product_name.c_str(),
+                  NULL,
+                  0,
+                  use_displayname ? displayname : username,
+                  CREDUI_MAX_USERNAME_LENGTH+1,
+                  password,
+                  CREDUI_MAX_PASSWORD_LENGTH+1,
+                  &save_password,
+                  kCredUiDefaultFlags |
+                  (tries > 1 ? CREDUI_FLAGS_INCORRECT_PASSWORD : 0));
+
+    if (credErr == NO_ERROR) {
+      logon_result = LogonUser(username,
+                               use_principalname ? NULL : L".",
+                               password,
+                               LOGON32_LOGON_NETWORK,
+                               LOGON32_PROVIDER_DEFAULT,
+                               &handle);
+      if (logon_result) {
+        retval = true;
+        CloseHandle(handle);
+      } else {
+        if (GetLastError() == ERROR_ACCOUNT_RESTRICTION &&
+            wcslen(password) == 0) {
+          // Password is blank, so permit.
+          retval = true;
+        } else {
+          DLOG(WARNING) << "Unable to authenticate " << GetLastError();
+        }
+      }
+      SecureZeroMemory(password, sizeof(password));
+    }
+  } while (credErr == NO_ERROR &&
+           (retval == false && tries < kMaxPasswordRetries));
+  return retval;
+}
+
+}  // namespace password_manager_util