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2+ * Copyright (C) 2013 Canonical, Ltd.
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.
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.
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/>.
16+ * Author: Michael Terry <michael.terry@canonical.com>
20+#include "GreeterPrivate.h"
22+#include <QFutureInterface>
23+#include <QFutureWatcher>
25+#include <QtConcurrent>
27+#include <security/pam_appl.h>
32+class GreeterImpl : public QObject
42+ typedef QFutureInterface<QString> ResponseFuture;
45+ explicit GreeterImpl(Greeter *parent, GreeterPrivate *greeterPrivate)
48+ greeterPrivate(greeterPrivate),
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);
68+ void start(QString username)
70+ // Clear out any existing PAM interactions first
72+ if (pamHandle != nullptr) {
73+ // While we were cancelling pam above, we processed Qt events.
74+ // Which may have allowed someone to call start() on us again.
75+ // In which case, we'll bail on our current start() call.
76+ // This isn't racy because it's all in the same thread.
80+ AppData *appData = new AppData();
81+ appData->impl = this;
83+ // Now actually start a new conversation with PAM
84+ pam_conv conversation;
85+ conversation.conv = converseWithPam;
86+ conversation.appdata_ptr = static_cast<void*>(appData);
88+ if (pam_start("lightdm", username.toUtf8(), &conversation, &pamHandle) == PAM_SUCCESS) {
89+ appData->handle = pamHandle;
90+ futureWatcher.setFuture(QtConcurrent::mapped(QList<pam_handle*>() << pamHandle, authenticateWithPam));
93+ greeterPrivate->authenticated = false;
94+ Q_EMIT greeter->showMessage("Internal error: could not start PAM authentication", QLightDM::Greeter::MessageTypeError);
95+ Q_EMIT greeter->authenticationComplete();
99+ static int authenticateWithPam(pam_handle* const& pamHandle)
101+ int pamStatus = pam_authenticate(pamHandle, 0);
102+ if (pamStatus == PAM_SUCCESS) {
103+ pamStatus = pam_acct_mgmt(pamHandle, 0);
105+ if (pamStatus == PAM_NEW_AUTHTOK_REQD) {
106+ pamStatus = pam_chauthtok(pamHandle, PAM_CHANGE_EXPIRED_AUTHTOK);
108+ if (pamStatus == PAM_SUCCESS) {
109+ pam_setcred(pamHandle, PAM_REINITIALIZE_CRED);
114+ static int converseWithPam(int num_msg, const pam_message** msg,
115+ pam_response** resp, void* appdata_ptr)
118+ return PAM_CONV_ERR;
120+ auto* tmp_response = static_cast<pam_response*>(calloc(num_msg, sizeof(pam_response)));
122+ return PAM_CONV_ERR;
124+ AppData *appData = static_cast<AppData*>(appdata_ptr);
125+ GreeterImpl *impl = appData->impl;
126+ pam_handle *handle = appData->handle;
129+ QVector<ResponseFuture> responses;
131+ for (count = 0; count < num_msg; ++count)
133+ switch (msg[count]->msg_style)
135+ case PAM_PROMPT_ECHO_ON:
137+ QString message(msg[count]->msg);
138+ responses.append(ResponseFuture());
139+ responses.last().reportStarted();
140+ Q_EMIT impl->showPrompt(handle, message, Greeter::PromptTypeQuestion, responses.last());
143+ case PAM_PROMPT_ECHO_OFF:
145+ QString message(msg[count]->msg);
146+ responses.append(ResponseFuture());
147+ responses.last().reportStarted();
148+ Q_EMIT impl->showPrompt(handle, message, Greeter::PromptTypeSecret, responses.last());
153+ QString message(msg[count]->msg);
154+ Q_EMIT impl->showMessage(handle, message, Greeter::MessageTypeInfo);
159+ QString message(msg[count]->msg);
160+ Q_EMIT impl->showMessage(handle, message, Greeter::MessageTypeError);
167+ bool raise_error = false;
169+ for (auto &response : responses)
171+ pam_response* resp_item = &tmp_response[i++];
172+ resp_item->resp_retcode = 0;
173+ resp_item->resp = strdup(response.future().result().toUtf8());
175+ if (!resp_item->resp)
186+ for (int i = 0; i < count; ++i)
187+ free(tmp_response[i].resp);
190+ return PAM_CONV_ERR;
194+ *resp = tmp_response;
200+ bool respond(QString response)
202+ if (!futures.isEmpty()) {
203+ futures.dequeue().reportFinished(&response);
211+ void showMessage(pam_handle *handle, QString text, QLightDM::Greeter::MessageType type);
212+ void showPrompt(pam_handle *handle, QString text, QLightDM::Greeter::PromptType type, QLightDM::GreeterImpl::ResponseFuture response);
217+ if (pamHandle == nullptr) {
221+ int pamStatus = futureWatcher.result();
223+ pam_end(pamHandle, pamStatus);
224+ pamHandle = nullptr;
226+ greeterPrivate->authenticated = (pamStatus == PAM_SUCCESS);
227+ Q_EMIT greeter->authenticationComplete();
230+ void handleMessage(pam_handle *handle, QString text, QLightDM::Greeter::MessageType type)
232+ if (handle != pamHandle)
235+ Q_EMIT greeter->showMessage(text, type);
238+ void handlePrompt(pam_handle *handle, QString text, QLightDM::Greeter::PromptType type, QLightDM::GreeterImpl::ResponseFuture future)
240+ if (handle != pamHandle) {
241+ future.reportResult(QString());
242+ future.reportFinished();
246+ futures.enqueue(future);
247+ Q_EMIT greeter->showPrompt(text, type);
253+ if (pamHandle != nullptr) {
254+ QFuture<int> pamFuture = futureWatcher.future();
255+ pam_handle *handle = pamHandle;
256+ pamHandle = nullptr; // to disable normal finishPam() handling
259+ // Note the empty loop, we just want to clear the futures queue.
260+ // Any further prompts from the pam thread will be immediately
261+ // responded to/dismissed in handlePrompt().
262+ while (respond(QString()));
264+ // Now let signal/slot handling happen so the thread can finish
265+ while (!pamFuture.isFinished()) {
266+ QCoreApplication::processEvents();
269+ pam_end(handle, PAM_CONV_ERR);
274+ GreeterPrivate *greeterPrivate;
275+ pam_handle* pamHandle;
276+ QFutureWatcher<int> futureWatcher;
277+ QQueue<ResponseFuture> futures;
280+GreeterPrivate::GreeterPrivate(Greeter* parent)
281+ : authenticated(false),
282+ authenticationUser(),
283+ m_impl(new GreeterImpl(parent, this)),
288+GreeterPrivate::~GreeterPrivate()
293+void GreeterPrivate::handleAuthenticate()
295+ m_impl->start(authenticationUser);
298+void GreeterPrivate::handleRespond(const QString &response)
300+ m_impl->respond(response);
305+#include "GreeterPrivate.moc"