Merge pull request #1449 from aleixpol/fix_priv_drop

Address privilege dropping

src/auth/Auth.cpp

@@ -69,7 +69,6 @@ namespace SDDM {
         bool autologin { false };
         bool greeter { false };
         QProcessEnvironment environment { };
-        qint64 sessionPid { -1 };
         qint64 id { 0 };
         static qint64 lastId;
     };
@@ -194,10 +193,8 @@ namespace SDDM {
             }
             case SESSION_STATUS: {
                 bool status;
-                qint64 pid; //not pid_t as we need to define the wire type
-                str >> status >> pid;
-                sessionPid = pid;
-                Q_EMIT auth->sessionStarted(status, pid);
+                str >> status;
+                Q_EMIT auth->sessionStarted(status);
                 str.reset();
                 str << SESSION_STATUS;
                 str.send();
@@ -301,10 +298,6 @@ namespace SDDM {
         return d->request;
     }
 
-    qint64 Auth::sessionPid() const {
-        return d->sessionPid;
-    }
-
     bool Auth::isActive() const {
         return d->child->state() != QProcess::NotRunning;
     }

src/auth/Auth.h

@@ -96,8 +96,6 @@ namespace SDDM {
         const QString &cookie() const;
         const QString &user() const;
         const QString &session() const;
-        qint64 sessionPid() const;
-
         AuthRequest *request();
         /**
          * True if an authentication or session is in progress
@@ -199,7 +197,7 @@ namespace SDDM {
         *
         * @param success true if succeeded
         */
-        void sessionStarted(bool success, qint64 pid);
+        void sessionStarted(bool success);
 
         /**
          * Emitted when the display server is ready.

src/common/VirtualTerminal.cpp

@@ -30,6 +30,7 @@
 #include <linux/vt.h>
 #include <linux/kd.h>
 #include <sys/ioctl.h>
+#include <qscopeguard.h>
 
 #define RELEASE_DISPLAY_SIGNAL (SIGRTMAX)
 #define ACQUIRE_DISPLAY_SIGNAL (SIGRTMAX - 1)
@@ -115,32 +116,57 @@ namespace SDDM {
                 qDebug() << "VT mode didn't need to be fixed";
         }
 
-        int setUpNewVt() {
+        int fetchAvailableVt() {
             // open VT master
             int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
             if (fd < 0) {
                 qCritical() << "Failed to open VT master:" << strerror(errno);
                 return -1;
             }
+            auto closeFd = qScopeGuard([fd] {
+                close(fd);
+            });
 
             vt_stat vtState = { 0 };
             if (ioctl(fd, VT_GETSTATE, &vtState) < 0) {
                 qCritical() << "Failed to get current VT:" << strerror(errno);
-                close(fd);
+
+                int vt = 0;
+                // If there's no current tty, request the next to open
+                if (ioctl(fd, VT_OPENQRY, &vt) < 0) {
+                    qCritical() << "Failed to open new VT:" << strerror(errno);
+                    return -1;
+                }
+                return vt;
+            }
+            return vtState.v_active;
+        }
+
+        int setUpNewVt() {
+            // open VT master
+            int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+            if (fd < 0) {
+                qCritical() << "Failed to open VT master:" << strerror(errno);
                 return -1;
             }
+            auto closeFd = qScopeGuard([fd] {
+                close(fd);
+            });
 
             int vt = 0;
             if (ioctl(fd, VT_OPENQRY, &vt) < 0) {
                 qCritical() << "Failed to open new VT:" << strerror(errno);
-                close(fd);
                 return -1;
             }
 
-            close(fd);
-
             // fallback to active VT
             if (vt <= 0) {
+                vt_stat vtState = { 0 };
+                if (ioctl(fd, VT_GETSTATE, &vtState) < 0) {
+                    qCritical() << "Failed to get current VT:" << strerror(errno);
+                    return -1;
+                }
+
                 qWarning() << "New VT" << vt << "is not valid, fall back to" << vtState.v_active;
                 return vtState.v_active;
             }

src/common/VirtualTerminal.h

@@ -22,6 +22,7 @@
 
 namespace SDDM {
     namespace VirtualTerminal {
+        int fetchAvailableVt();
         int setUpNewVt();
         void jumpToVt(int vt, bool vt_auto);
     }

src/daemon/Display.cpp

@@ -35,7 +35,6 @@
 #include <QFile>
 #include <QTimer>
 #include <QLocalSocket>
-#include <QByteArray>
 
 #include <pwd.h>
 #include <unistd.h>
@@ -49,10 +48,6 @@
 #include "VirtualTerminal.h"
 #include "WaylandDisplayServer.h"
 
-#if defined(Q_OS_LINUX)
-#include <utmp.h>
-#endif
-#include <utmpx.h>
 
 namespace SDDM {
     Display::Display(Seat *parent) : QObject(parent),
@@ -139,10 +134,6 @@ namespace SDDM {
         return m_displayServer;
     }
 
-    QString Display::displayId() const {
-        return m_displayServer->display();
-    }
-
     const int Display::terminalId() const {
         return m_terminalId;
     }
@@ -373,11 +364,14 @@ namespace SDDM {
 
         // New VT
         if (session.xdgSessionType() != QLatin1String("x11") || m_displayServerType != X11DisplayServerType) {
-            m_lastSession.setVt(VirtualTerminal::setUpNewVt());
+            if (m_displayServerType == X11DisplayServerType)
+                m_lastSession.setVt(VirtualTerminal::setUpNewVt());
+            else
+                m_lastSession.setVt(VirtualTerminal::fetchAvailableVt());
         }
 
         // some information
-        qDebug() << "Session" << m_sessionName << "selected, command:" << session.exec();
+        qDebug() << "Session" << m_sessionName << "selected, command:" << session.exec() << "for VT" << m_lastSession.vt();
 
         QProcessEnvironment env;
         env.insert(session.additionalEnv());
@@ -437,7 +431,6 @@ namespace SDDM {
             if (m_socket)
                 emit loginSucceeded(m_socket);
         } else if (m_socket) {
-            utmpLogin(QString::number(terminalId()),  name(), user, 0, false);
             qDebug() << "Authentication failure";
             emit loginFailed(m_socket);
         }
@@ -462,10 +455,6 @@ namespace SDDM {
     }
 
     void Display::slotHelperFinished(Auth::HelperExitStatus status) {
-        if (m_auth->sessionPid() > 0) {
-            utmpLogout(QString::number(terminalId()), name(), m_auth->sessionPid());
-        }
-
         // Don't restart greeter and display server unless sddm-helper exited
         // with an internal error or the user session finished successfully,
         // we want to avoid greeter from restarting when an authentication
@@ -490,104 +479,7 @@ namespace SDDM {
         }
     }
 
-    void Display::slotSessionStarted(bool success, qint64 pid) {
-        if (success) {
-            utmpLogin(QString::number(terminalId()), name(), m_auth->user(), pid, true);
-        }
+    void Display::slotSessionStarted(bool success) {
+        qDebug() << "Session started";
     }
-
-    void Display::utmpLogin(const QString &vt, const QString &displayName, const QString &user, qint64 pid, bool authSuccessful) {
-        struct utmpx entry;
-        struct timeval tv;
-
-        entry = { 0 };
-        entry.ut_type = USER_PROCESS;
-        entry.ut_pid = pid;
-
-        // ut_line: vt
-        if (!vt.isEmpty()) {
-            QString tty = QStringLiteral("tty");
-            tty.append(vt);
-            QByteArray ttyBa = tty.toLocal8Bit();
-            const char* ttyChar = ttyBa.constData();
-            strncpy(entry.ut_line, ttyChar, sizeof(entry.ut_line) - 1);
-        }
-
-        // ut_host: displayName
-        QByteArray displayBa = displayName.toLocal8Bit();
-        const char* displayChar = displayBa.constData();
-        strncpy(entry.ut_host, displayChar, sizeof(entry.ut_host) - 1);
-
-        // ut_user: user
-        QByteArray userBa = user.toLocal8Bit();
-        const char* userChar = userBa.constData();
-        strncpy(entry.ut_user, userChar, sizeof(entry.ut_user) -1);
-
-        gettimeofday(&tv, NULL);
-        entry.ut_tv.tv_sec = tv.tv_sec;
-        entry.ut_tv.tv_usec = tv.tv_usec;
-
-        // write to utmp
-        setutxent();
-        if (!pututxline (&entry))
-            qWarning() << "Failed to write utmpx: " << strerror(errno);
-        endutxent();
-
-#if !defined(Q_OS_FREEBSD)
-        // append to failed login database btmp
-        if (!authSuccessful) {
-#if defined(Q_OS_LINUX)
-            updwtmpx("/var/log/btmp", &entry);
-#endif
-        }
-
-        // append to wtmp
-        else {
-#if defined(Q_OS_LINUX)
-            updwtmpx("/var/log/wtmp", &entry);
-#endif
-        }
-#endif
-    }
-
-    void Display::utmpLogout(const QString &vt, const QString &displayName, qint64 pid) {
-        struct utmpx entry;
-        struct timeval tv;
-
-        entry = { 0 };
-        entry.ut_type = DEAD_PROCESS;
-        entry.ut_pid = pid;
-
-        // ut_line: vt
-        if (!vt.isEmpty()) {
-            QString tty = QStringLiteral("tty");
-            tty.append(vt);
-            QByteArray ttyBa = tty.toLocal8Bit();
-            const char* ttyChar = ttyBa.constData();
-            strncpy(entry.ut_line, ttyChar, sizeof(entry.ut_line) - 1);
-        }
-
-        // ut_host: displayName
-        QByteArray displayBa = displayName.toLocal8Bit();
-        const char* displayChar = displayBa.constData();
-        strncpy(entry.ut_host, displayChar, sizeof(entry.ut_host) - 1);
-
-        gettimeofday(&tv, NULL);
-        entry.ut_tv.tv_sec = tv.tv_sec;
-        entry.ut_tv.tv_usec = tv.tv_usec;
-
-        // write to utmp
-        setutxent();
-        if (!pututxline (&entry))
-            qWarning() << "Failed to write utmpx: " << strerror(errno);
-        endutxent();
-
-#if defined(Q_OS_LINUX)
-        // append to wtmp
-        updwtmpx("/var/log/wtmp", &entry);
-#elif defined(Q_OS_FREEBSD)
-        pututxline(&entry);
-#endif
-    }
-
 }

src/daemon/Display.h

@@ -54,7 +54,6 @@ namespace SDDM {
         DisplayServerType displayServerType() const;
         DisplayServer *displayServer() const;
 
-        QString displayId() const;
         const int terminalId() const;
 
         const QString &name() const;
@@ -106,28 +105,10 @@ namespace SDDM {
         QLocalSocket *m_socket { nullptr };
         Greeter *m_greeter { nullptr };
 
-        /*!
-         \brief Write utmp/wtmp/btmp records when a user logs in
-         \param vt  Virtual terminal (tty7, tty8,...)
-         \param displayName  Display (:0, :1,...)
-         \param user  User logging in
-         \param pid  User process ID (e.g. PID of startkde)
-         \param authSuccessful  Was authentication successful
-        */
-        void utmpLogin(const QString &vt, const QString &displayName, const QString &user, qint64 pid, bool authSuccessful);
-
-        /*!
-         \brief Write utmp/wtmp records when a user logs out
-         \param vt  Virtual terminal (tty7, tty8,...)
-         \param displayName  Display (:0, :1,...)
-         \param pid  User process ID (e.g. PID of startkde)
-        */
-        void utmpLogout(const QString &vt, const QString &displayName, qint64 pid);
-
     private slots:
         void slotRequestChanged();
         void slotAuthenticationFinished(const QString &user, bool success);
-        void slotSessionStarted(bool success, qint64 pid);
+        void slotSessionStarted(bool success);
         void slotHelperFinished(Auth::HelperExitStatus status);
         void slotAuthInfo(const QString &message, Auth::Info info);
         void slotAuthError(const QString &message, Auth::Error error);

src/daemon/Seat.cpp

@@ -77,7 +77,7 @@ namespace SDDM {
     }
 
     void Seat::removeDisplay(Display* display) {
-        qDebug() << "Removing display" << display->displayId() << "...";
+        qDebug() << "Removing display" << display << "...";
 
 
         // remove display from list

src/helper/CMakeLists.txt

@@ -15,10 +15,6 @@ set(HELPER_SOURCES
     Backend.cpp
     HelperApp.cpp
     UserSession.cpp
-    xorguserhelper.cpp
-    xorguserhelper.h
-    waylandhelper.cpp
-    waylandsocketwatcher.cpp
 )
 
 # Different implementations of the VT switching code
@@ -66,8 +62,22 @@ else()
     target_link_libraries(sddm-helper crypt)
 endif()
 
+install(TARGETS sddm-helper RUNTIME DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}")
+
+add_executable(sddm-helper-start-wayland HelperStartWayland.cpp waylandsocketwatcher.cpp waylandhelper.cpp)
+target_link_libraries(sddm-helper-start-wayland Qt5::Core)
+install(TARGETS sddm-helper-start-wayland RUNTIME DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}")
+
+add_executable(sddm-helper-start-x11user HelperStartX11User.cpp xorguserhelper.cpp
+                                                ${CMAKE_SOURCE_DIR}/src/common/ConfigReader.cpp
+                                                ${CMAKE_SOURCE_DIR}/src/common/Configuration.cpp
+                                                ${CMAKE_SOURCE_DIR}/src/common/XAuth.cpp
+                                                )
+target_link_libraries(sddm-helper-start-x11user Qt5::Core)
+install(TARGETS sddm-helper-start-x11user RUNTIME DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}")
+
 if(JOURNALD_FOUND)
     target_link_libraries(sddm-helper ${JOURNALD_LIBRARIES})
+    target_link_libraries(sddm-helper-start-x11user ${JOURNALD_LIBRARIES})
+    target_link_libraries(sddm-helper-start-wayland ${JOURNALD_LIBRARIES})
 endif()
-
-install(TARGETS sddm-helper RUNTIME DESTINATION "${CMAKE_INSTALL_LIBEXECDIR}")