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| 1 | +// Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 | +// Use of this source code is governed by a BSD-style license that can be |
| 3 | +// found in the LICENSE file. |
| 4 | + |
| 5 | +#include "chrome/browser/chromeos/system/drm_settings.h" |
| 6 | + |
| 7 | +#include "base/bind.h" |
| 8 | +#include "base/chromeos/chromeos_version.h" |
| 9 | +#include "base/command_line.h" |
| 10 | +#include "base/file_path.h" |
| 11 | +#include "base/file_util.h" |
| 12 | +#include "base/path_service.h" |
| 13 | +#include "base/string_number_conversions.h" |
| 14 | +#include "base/string_util.h" |
| 15 | +#include "chrome/browser/chromeos/cros/cros_library.h" |
| 16 | +#include "chrome/browser/chromeos/cros/cryptohome_library.h" |
| 17 | +#include "chrome/browser/chromeos/login/user_manager.h" |
| 18 | +#include "chrome/common/chrome_paths.h" |
| 19 | +#include "chrome/common/chrome_switches.h" |
| 20 | +#include "content/public/browser/browser_thread.h" |
| 21 | +#include "crypto/encryptor.h" |
| 22 | +#include "crypto/sha2.h" |
| 23 | + |
| 24 | +using content::BrowserThread; |
| 25 | + |
| 26 | +namespace { |
| 27 | + |
| 28 | +// This constant is mirrored in |
| 29 | +// content/browser/renderer_host/pepper_message_filter.cc |
| 30 | +// for OnGetDeviceID. |
| 31 | +// |
| 32 | +// This ID file is solely for use via the private pepper API. |
| 33 | +// |
| 34 | +// NOTE! Changing this value will also change the generated value |
| 35 | +// do not do so without accounting for the change. |
| 36 | +const char kDRMIdentifierFile[] = "Pepper DRM ID.0"; |
| 37 | + |
| 38 | +void ManageDrmIdentifierOnFileThread(bool enable, const std::string& email) { |
| 39 | + DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); |
| 40 | + |
| 41 | + // Drop the file under <data>/<profile>/<drm id file>. |
| 42 | + // TODO(wad) get the profile directory in a more succinct fashion. |
| 43 | + FilePath drm_id_file; |
| 44 | + PathService::Get(chrome::DIR_USER_DATA, &drm_id_file); |
| 45 | + const CommandLine& cmd_line = *CommandLine::ForCurrentProcess(); |
| 46 | + FilePath profile = cmd_line.GetSwitchValuePath(switches::kLoginProfile); |
| 47 | + if (profile.empty()) { |
| 48 | + LOG(ERROR) << "called with no login-profile!"; |
| 49 | + return; |
| 50 | + } |
| 51 | + drm_id_file = drm_id_file.AppendASCII(profile.value()); |
| 52 | + drm_id_file = drm_id_file.AppendASCII(kDRMIdentifierFile); |
| 53 | + |
| 54 | + // The file will be regenerated or deleted at toggle-time. |
| 55 | + file_util::Delete(drm_id_file, false); |
| 56 | + |
| 57 | + // If DRM support is disabled, then do nothing else. |
| 58 | + if (!enable) |
| 59 | + return; |
| 60 | + |
| 61 | + // Build the identifier as follows: |
| 62 | + // SHA256(system-salt||service||SHA256(system-salt||service||email)) |
| 63 | + chromeos::CryptohomeLibrary* c_home = |
| 64 | + chromeos::CrosLibrary::Get()->GetCryptohomeLibrary(); |
| 65 | + std::string salt = c_home->GetSystemSalt(); |
| 66 | + char id_buf[256 / 8]; // 256-bits for SHA256 |
| 67 | + std::string input = salt; |
| 68 | + input.append(kDRMIdentifierFile); |
| 69 | + input.append(email); |
| 70 | + crypto::SHA256HashString(input, &id_buf, sizeof(id_buf)); |
| 71 | + std::string id = StringToLowerASCII(base::HexEncode( |
| 72 | + reinterpret_cast<const void*>(id_buf), |
| 73 | + sizeof(id_buf))); |
| 74 | + input = salt; |
| 75 | + input.append(kDRMIdentifierFile); |
| 76 | + input.append(id); |
| 77 | + crypto::SHA256HashString(input, &id_buf, sizeof(id_buf)); |
| 78 | + id = StringToLowerASCII(base::HexEncode( |
| 79 | + reinterpret_cast<const void*>(id_buf), |
| 80 | + sizeof(id_buf))); |
| 81 | + |
| 82 | + if (file_util::WriteFile(drm_id_file, id.c_str(), id.length()) != |
| 83 | + static_cast<int>(id.length())) { |
| 84 | + LOG(ERROR) << "Failed to write " << drm_id_file.value(); |
| 85 | + return; |
| 86 | + } |
| 87 | +} |
| 88 | + |
| 89 | +} // namespace |
| 90 | + |
| 91 | +namespace chromeos { |
| 92 | +namespace system { |
| 93 | + |
| 94 | +void ToggleDrm(bool enable) { |
| 95 | + DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI)); |
| 96 | + |
| 97 | + // Never generate the file in Guest mode. |
| 98 | + if (UserManager::Get()->IsLoggedInAsGuest() || |
| 99 | + UserManager::Get()->IsLoggedInAsDemoUser()) |
| 100 | + return; |
| 101 | + |
| 102 | + // The user email address is included in the hash to keep the identifier |
| 103 | + // from being the same across users. |
| 104 | + std::string email = UserManager::Get()->GetLoggedInUser().email(); |
| 105 | + DCHECK(email.length() == 0); |
| 106 | + |
| 107 | + // Generate a DRM identifier on the FILE thread. |
| 108 | + // The DRM identifier is a per-user, per-OS-install identifier that is used |
| 109 | + // by privileged pepper plugins specifically for deriving |
| 110 | + // per-content-provider identifiers. The user must be able to clear it, |
| 111 | + // reset it, and deny its use. |
| 112 | + BrowserThread::PostTask( |
| 113 | + BrowserThread::FILE, FROM_HERE, |
| 114 | + base::Bind(&ManageDrmIdentifierOnFileThread, enable, email)); |
| 115 | +} |
| 116 | + |
| 117 | +} // namespace system |
| 118 | +} // namespace chromeos |
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