plugins/LightDM/liblightdm/GreeterPrivate.cpp · unity8

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unity8/plugins/LightDM/liblightdm/GreeterPrivate.cpp

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1/*

3 *

4 * This program is free software; you can redistribute it and/or modify

5 * it under the terms of the GNU General Public License as published by

6 * the Free Software Foundation; version 3.

7 *

8 * This program is distributed in the hope that it will be useful,

9 * but WITHOUT ANY WARRANTY; without even the implied warranty of

10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

11 * GNU General Public License for more details.

12 *

13 * You should have received a copy of the GNU General Public License

14 * along with this program. If not, see <http://www.gnu.org/licenses/>.

15 *

16 * Author: Michael Terry <michael.terry@canonical.com>

17 */

19#include "Greeter.h"

20#include "GreeterPrivate.h"

21#include <QFuture>

22#include <QFutureInterface>

23#include <QFutureWatcher>

24#include <QQueue>

25#include <QtConcurrent>

26#include <QVector>

27#include <security/pam_appl.h>

29namespace QLightDM

30{

32class GreeterImpl : public QObject

33{

34 Q_OBJECT

36 struct AppData

37 {

38 GreeterImpl *impl;

39 pam_handle *handle;

40 };

42 typedef QFutureInterface<QString> ResponseFuture;

44public:

45 explicit GreeterImpl(Greeter *parent, GreeterPrivate *greeterPrivate)

46 : QObject(parent),

47 greeter(parent),

48 greeterPrivate(greeterPrivate),

49 pamHandle(nullptr)

50 {

51 qRegisterMetaType<QLightDM::GreeterImpl::ResponseFuture>("QLightDM::GreeterImpl::ResponseFuture");

53 connect(&futureWatcher, SIGNAL(finished()),

54 this, SLOT(finishPam()));

55 connect(this, SIGNAL(showMessage(pam_handle *, QString, QLightDM::Greeter::MessageType)),

56 this, SLOT(handleMessage(pam_handle *, QString, QLightDM::Greeter::MessageType)));

57 // This next connect is how we pass ResponseFutures between threads

58 connect(this, SIGNAL(showPrompt(pam_handle *, QString, QLightDM::Greeter::PromptType, QLightDM::GreeterImpl::ResponseFuture)),

59 this, SLOT(handlePrompt(pam_handle *, QString, QLightDM::Greeter::PromptType, QLightDM::GreeterImpl::ResponseFuture)),

60 Qt::BlockingQueuedConnection);

61 }

63 ~GreeterImpl()

64 {

65 cancelPam();

66 }

68 void start(QString username)

69 {

70 // Clear out any existing PAM interactions first

71 cancelPam();

73 AppData *appData = new AppData();

74 appData->impl = this;

76 // Now actually start a new conversation with PAM

77 pam_conv conversation;

78 conversation.conv = converseWithPam;

79 conversation.appdata_ptr = static_cast<void*>(appData);

81 if (pam_start("lightdm", username.toUtf8(), &conversation, &pamHandle) == PAM_SUCCESS) {

82 appData->handle = pamHandle;

83 futureWatcher.setFuture(QtConcurrent::mapped(QList<pam_handle*>() << pamHandle, authenticateWithPam));

84 } else {

85 delete appData;

86 greeterPrivate->authenticated = false;

87 Q_EMIT greeter->showMessage("Internal error: could not start PAM authentication", QLightDM::Greeter::MessageTypeError);

88 Q_EMIT greeter->authenticationComplete();

89 }

90 }

92 static int authenticateWithPam(pam_handle* const& pamHandle)

93 {

94 int pamStatus = pam_authenticate(pamHandle, 0);

95 if (pamStatus == PAM_SUCCESS) {

96 pamStatus = pam_acct_mgmt(pamHandle, 0);

97 }

98 if (pamStatus == PAM_NEW_AUTHTOK_REQD) {

99 pamStatus = pam_chauthtok(pamHandle, PAM_CHANGE_EXPIRED_AUTHTOK);

100 }

101 if (pamStatus == PAM_SUCCESS) {

102 pam_setcred(pamHandle, PAM_REINITIALIZE_CRED);

103 }

104 return pamStatus;

105 }

106

107 static int converseWithPam(int num_msg, const pam_message** msg,

108 pam_response** resp, void* appdata_ptr)

109 {

110 if (num_msg <= 0)

111 return PAM_CONV_ERR;

112

113 auto* tmp_response = static_cast<pam_response*>(calloc(num_msg, sizeof(pam_response)));

114 if (!tmp_response)

115 return PAM_CONV_ERR;

116

117 AppData *appData = static_cast<AppData*>(appdata_ptr);

118 GreeterImpl *impl = appData->impl;

119 pam_handle *handle = appData->handle;

120

121 int count;

122 QVector<ResponseFuture> responses;

123

124 for (count = 0; count < num_msg; ++count)

125 {

126 switch (msg[count]->msg_style)

127 {

128 case PAM_PROMPT_ECHO_ON:

129 {

130 QString message(msg[count]->msg);

131 responses.append(ResponseFuture());

132 responses.last().reportStarted();

133 Q_EMIT impl->showPrompt(handle, message, Greeter::PromptTypeQuestion, responses.last());

134 break;

135 }

136 case PAM_PROMPT_ECHO_OFF:

137 {

138 QString message(msg[count]->msg);

139 responses.append(ResponseFuture());

140 responses.last().reportStarted();

141 Q_EMIT impl->showPrompt(handle, message, Greeter::PromptTypeSecret, responses.last());

142 break;

143 }

144 case PAM_TEXT_INFO:

145 {

146 QString message(msg[count]->msg);

147 Q_EMIT impl->showMessage(handle, message, Greeter::MessageTypeInfo);

148 break;

149 }

150 default:

151 {

152 QString message(msg[count]->msg);

153 Q_EMIT impl->showMessage(handle, message, Greeter::MessageTypeError);

154 break;

155 }

156 }

157 }

158

159 int i = 0;

160 bool raise_error = false;

161

162 for (auto &response : responses)

163 {

164 pam_response* resp_item = &tmp_response[i++];

165 resp_item->resp_retcode = 0;

166 resp_item->resp = strdup(response.future().result().toUtf8());

167

168 if (!resp_item->resp)

169 {

170 raise_error = true;

171 break;

172 }

173 }

174

175 delete appData;

176

177 if (raise_error)

178 {

179 for (int i = 0; i < count; ++i)

180 free(tmp_response[i].resp);

181

182 free(tmp_response);

183 return PAM_CONV_ERR;

184 }

185 else

186 {

187 *resp = tmp_response;

188 return PAM_SUCCESS;

189 }

190 }

191

192public Q_SLOTS:

193 bool respond(QString response)

194 {

195 if (!futures.isEmpty()) {

196 futures.dequeue().reportFinished(&response);

197 return true;

198 } else {

199 return false;

200 }

201 }

202

203Q_SIGNALS:

204 void showMessage(pam_handle *handle, QString text, QLightDM::Greeter::MessageType type);

205 void showPrompt(pam_handle *handle, QString text, QLightDM::Greeter::PromptType type, QLightDM::GreeterImpl::ResponseFuture response);

206

207private Q_SLOTS:

208 void finishPam()

209 {

210 if (pamHandle == nullptr) {

211 return;

212 }

213

214 int pamStatus = futureWatcher.result();

215

216 pam_end(pamHandle, pamStatus);

217 pamHandle = nullptr;

218

219 greeterPrivate->authenticated = (pamStatus == PAM_SUCCESS);

220 Q_EMIT greeter->authenticationComplete();

221 }

222

223 void handleMessage(pam_handle *handle, QString text, QLightDM::Greeter::MessageType type)

224 {

225 if (handle != pamHandle)

226 return;

227

228 Q_EMIT greeter->showMessage(text, type);

229 }

230

231 void handlePrompt(pam_handle *handle, QString text, QLightDM::Greeter::PromptType type, QLightDM::GreeterImpl::ResponseFuture future)

232 {

233 if (handle != pamHandle) {

234 future.reportResult(QString());

235 future.reportFinished();

236 return;

237 }

238

239 futures.enqueue(future);

240 Q_EMIT greeter->showPrompt(text, type);

241 }

242

243private:

244 void cancelPam()

245 {

246 if (pamHandle != nullptr) {

247 pam_handle *handle = pamHandle;

248 pamHandle = nullptr; // to disable normal finishPam() handling

249 futureWatcher.future().cancel();

250 while (!futureWatcher.future().isFinished()) {

251 QCoreApplication::processEvents(); // let signal/slot handling happen

252 respond(QString());

253 }

254 pam_end(handle, PAM_CONV_ERR);

255 }

256 }

257

258 Greeter *greeter;

259 GreeterPrivate *greeterPrivate;

260 pam_handle* pamHandle;

261 QFutureWatcher<int> futureWatcher;

262 QQueue<ResponseFuture> futures;

263};

264

265GreeterPrivate::GreeterPrivate(Greeter* parent)

266 : authenticated(false),

267 authenticationUser(),

268 m_impl(new GreeterImpl(parent, this)),

269 q_ptr(parent)

270{

271}

272

273GreeterPrivate::~GreeterPrivate()

274{

275 delete m_impl;

276}

277

278void GreeterPrivate::handleAuthenticate()

279{

280 m_impl->start(authenticationUser);

281}

282

283void GreeterPrivate::handleRespond(const QString &response)

284{

285 m_impl->respond(response);

286}

287

288}

289

290#include "GreeterPrivate.moc"