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// Copyright 2007-2021 The Mumble Developers. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file at the root of the
// Mumble source tree or at <https://www.mumble.info/LICENSE>.
#include "UnixMurmur.h"
#include "EnvUtils.h"
#include "Meta.h"
#include <QtCore/QAbstractEventDispatcher>
#include <QtCore/QCoreApplication>
#include <QtCore/QMutex>
#include <QtCore/QSocketNotifier>
#include <QtCore/QWaitCondition>
#include <grp.h>
#include <signal.h>
#ifdef Q_OS_LINUX
# include <sys/capability.h>
# include <sys/prctl.h>
# include <sys/resource.h>
#endif
#include <sys/socket.h>
#include <sys/stat.h>
#include <unistd.h>
#include <limits>
QMutex *LimitTest::qm;
QWaitCondition *LimitTest::qw;
QWaitCondition *LimitTest::qstartw;
LimitTest::LimitTest() : QThread(), tid(-1) {
}
void LimitTest::run() {
qm->lock();
qstartw->wakeAll();
qw->wait(qm);
qm->unlock();
}
void LimitTest::testLimits(QCoreApplication &a) {
QAbstractEventDispatcher *ed = QAbstractEventDispatcher::instance();
if (QLatin1String(ed->metaObject()->className()) != QLatin1String("QEventDispatcherGlib"))
qWarning(
"Not running with glib. While you may be able to open more descriptors, sockets above %d will not work",
FD_SETSIZE);
qWarning("Running descriptor test.");
int count;
QList< QFile * > ql;
for (count = 0; count < 524288; ++count) {
QFile *qf = new QFile(a.applicationFilePath());
if (qf->open(QIODevice::ReadOnly))
ql.prepend(qf);
else
break;
if ((count & 1023) == 0)
qWarning("%d descriptors...", count);
}
foreach (QFile *qf, ql)
delete qf;
ql.clear();
qCritical("Managed to open %d descriptors", count);
qm = new QMutex();
qw = new QWaitCondition();
qstartw = new QWaitCondition();
int fdcount = count / 8;
if (sizeof(void *) < 8)
if (fdcount > 1024)
fdcount = 1024;
QList< LimitTest * > qtl;
for (count = 0; count < fdcount; ++count) {
LimitTest *t = new LimitTest();
t->tid = count;
qtl << t;
qm->lock();
t->start();
qstartw->wait(qm);
qm->unlock();
if (!t->isRunning())
break;
if ((count & 511) == 0)
qWarning("%d threads...", count);
}
qm->lock();
qw->wakeAll();
qm->unlock();
foreach (LimitTest *qt, qtl) {
if (!qt->wait(1000)) {
qWarning("Thread %d failed to terminate...", qt->tid);
qt->terminate();
}
}
qFatal("Managed to spawn %d threads", count);
}
extern QFile *qfLog;
int UnixMurmur::iHupFd[2];
int UnixMurmur::iTermFd[2];
int UnixMurmur::iUsr1Fd[2];
UnixMurmur::UnixMurmur() {
bRoot = true;
logToSyslog = false;
if (geteuid() != 0 && getuid() != 0) {
bRoot = false;
}
if (::socketpair(AF_UNIX, SOCK_STREAM, 0, iHupFd))
qFatal("Couldn't create HUP socketpair");
if (::socketpair(AF_UNIX, SOCK_STREAM, 0, iTermFd))
qFatal("Couldn't create TERM socketpair");
if (::socketpair(AF_UNIX, SOCK_STREAM, 0, iUsr1Fd))
qFatal("Couldn't create USR1 socketpair");
qsnHup = new QSocketNotifier(iHupFd[1], QSocketNotifier::Read, this);
qsnTerm = new QSocketNotifier(iTermFd[1], QSocketNotifier::Read, this);
qsnUsr1 = new QSocketNotifier(iUsr1Fd[1], QSocketNotifier::Read, this);
connect(qsnHup, SIGNAL(activated(int)), this, SLOT(handleSigHup()));
connect(qsnTerm, SIGNAL(activated(int)), this, SLOT(handleSigTerm()));
connect(qsnUsr1, SIGNAL(activated(int)), this, SLOT(handleSigUsr1()));
struct sigaction hup, term, usr1;
hup.sa_handler = hupSignalHandler;
sigemptyset(&hup.sa_mask);
hup.sa_flags = SA_RESTART;
if (sigaction(SIGHUP, &hup, nullptr))
qFatal("Failed to install SIGHUP handler");
term.sa_handler = termSignalHandler;
sigemptyset(&term.sa_mask);
term.sa_flags = SA_RESTART;
if (sigaction(SIGTERM, &term, nullptr))
qFatal("Failed to install SIGTERM handler");
usr1.sa_handler = usr1SignalHandler;
sigemptyset(&usr1.sa_mask);
usr1.sa_flags = SA_RESTART;
if (sigaction(SIGUSR1, &usr1, nullptr))
qFatal("Failed to install SIGUSR1 handler");
umask(S_IRWXO);
}
UnixMurmur::~UnixMurmur() {
delete qsnHup;
delete qsnTerm;
delete qsnUsr1;
qsnHup = nullptr;
qsnTerm = nullptr;
qsnUsr1 = nullptr;
close(iHupFd[0]);
close(iHupFd[1]);
close(iTermFd[0]);
close(iTermFd[1]);
close(iUsr1Fd[0]);
close(iUsr1Fd[1]);
}
void UnixMurmur::hupSignalHandler(int) {
char a = 1;
ssize_t len = ::write(iHupFd[0], &a, sizeof(a));
Q_UNUSED(len);
}
void UnixMurmur::termSignalHandler(int) {
char a = 1;
ssize_t len = ::write(iTermFd[0], &a, sizeof(a));
Q_UNUSED(len);
}
void UnixMurmur::usr1SignalHandler(int) {
char a = 1;
ssize_t len = ::write(iUsr1Fd[0], &a, sizeof(a));
Q_UNUSED(len);
}
// Keep these two synchronized with matching actions in DBus.cpp
void UnixMurmur::handleSigHup() {
qsnHup->setEnabled(false);
char tmp;
ssize_t len = ::read(iHupFd[1], &tmp, sizeof(tmp));
Q_UNUSED(len);
if (logToSyslog) {
qWarning("Caught SIGHUP, but logging to syslog");
} else if (!qfLog) {
qWarning("Caught SIGHUP, but logfile not in use");
} else if (!qfLog->isOpen()) {
qWarning("Caught SIGHUP, but logfile not in use -- interpreting as hint to quit");
QCoreApplication::instance()->quit();
} else {
qWarning("Caught SIGHUP, will reopen %s", qPrintable(Meta::mp.qsLogfile));
QFile *newlog = new QFile(Meta::mp.qsLogfile);
bool result = newlog->open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text);
if (!result) {
delete newlog;
qCritical("Failed to reopen logfile for writing, keeping old log");
} else {
QFile *oldlog = qfLog;
newlog->setTextModeEnabled(true);
qfLog = newlog;
oldlog->close();
delete oldlog;
qWarning("Log rotated successfully");
}
}
qsnHup->setEnabled(true);
}
void UnixMurmur::handleSigTerm() {
qsnTerm->setEnabled(false);
char tmp;
ssize_t len = ::read(iTermFd[1], &tmp, sizeof(tmp));
Q_UNUSED(len);
qCritical("Caught SIGTERM, exiting");
QCoreApplication::instance()->quit();
qsnTerm->setEnabled(true);
}
void UnixMurmur::handleSigUsr1() {
qsnUsr1->setEnabled(false);
char tmp;
ssize_t len = ::read(iUsr1Fd[1], &tmp, sizeof(tmp));
Q_UNUSED(len);
if (meta) {
qWarning("UnixMurmur: Trying to reload SSL settings...");
bool ok = meta->reloadSSLSettings();
if (ok) {
qWarning("UnixMurmur: Done reloading SSL settings.");
} else {
qWarning("UnixMurmur: Failed to reload SSL settings. Server state is intact and fully operational. No "
"configuration changes were made.");
}
}
qsnUsr1->setEnabled(true);
}
void UnixMurmur::setuid() {
if (Meta::mp.uiUid != 0) {
#ifdef Q_OS_DARWIN
qCritical("WARNING: You are launching murmurd as root on Mac OS X or Darwin. Murmur does not need "
"special privileges to set itself up on these systems, so this behavior is highly discouraged.");
if (::setgid(Meta::mp.uiGid) != 0)
qFatal("Failed to switch to gid %d", Meta::mp.uiGid);
if (::setuid(Meta::mp.uiUid) != 0)
qFatal("Failed to switch to uid %d", Meta::mp.uiUid);
uid_t uid = getuid(), euid = geteuid();
gid_t gid = getgid(), egid = getegid();
if (uid == Meta::mp.uiUid && euid == Meta::mp.uiUid && gid == Meta::mp.uiGid && egid == Meta::mp.uiGid) {
qCritical("Successfully switched to uid %d", Meta::mp.uiUid);
} else
qFatal("Couldn't switch uid/gid.");
#else
if (::initgroups(qPrintable(Meta::mp.qsName), Meta::mp.uiGid) != 0)
qCritical("Can't initialize supplementary groups");
if (::setgid(Meta::mp.uiGid) != 0)
qCritical("Failed to switch to gid %d", Meta::mp.uiGid);
if (::setuid(Meta::mp.uiUid) != 0) {
qFatal("Failed to become uid %d", Meta::mp.uiUid);
} else {
qCritical("Successfully switched to uid %d", Meta::mp.uiUid);
initialcap();
}
if (!Meta::mp.qsHome.isEmpty()) {
// QDir::homePath is broken. It only looks at $HOME
// instead of getpwuid() so we have to set our home
// ourselves
EnvUtils::setenv(QLatin1String("HOME"), Meta::mp.qsHome);
}
#endif
} else if (bRoot) {
qCritical("WARNING: You are running murmurd as root, without setting a uname in the ini file. This might be a "
"security risk.");
}
}
void UnixMurmur::initialcap() {
#ifdef Q_OS_LINUX
cap_value_t caps[] = { CAP_NET_ADMIN, CAP_SETUID, CAP_SETGID, CAP_CHOWN, CAP_SYS_RESOURCE, CAP_DAC_OVERRIDE };
if (!bRoot)
return;
int ncap = sizeof(caps) / sizeof(cap_value_t);
if (geteuid() != 0)
ncap--;
cap_t c = cap_init();
cap_clear(c);
cap_set_flag(c, CAP_EFFECTIVE, ncap, caps, CAP_SET);
cap_set_flag(c, CAP_INHERITABLE, ncap, caps, CAP_SET);
cap_set_flag(c, CAP_PERMITTED, ncap, caps, CAP_SET);
if (cap_set_proc(c) != 0) {
qCritical("Failed to set initial capabilities");
} else {
prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0);
}
cap_free(c);
#endif
}
void UnixMurmur::finalcap() {
#ifdef Q_OS_LINUX
cap_value_t caps[] = { CAP_SYS_RESOURCE };
struct rlimit r;
if (!bRoot)
return;
if (getrlimit(RLIMIT_RTPRIO, &r) != 0) {
qCritical("Failed to get priority limits.");
} else {
using ulong_t = unsigned long long int;
static_assert(std::numeric_limits< ulong_t >::max() >= std::numeric_limits< rlim_t >::max(), "rlim_t is unexpectedly large");
ulong_t current = r.rlim_cur;
ulong_t max = r.rlim_max;
qWarning("Resource limits were %llu %llu", current, max);
r.rlim_cur = r.rlim_max = 1;
if (setrlimit(RLIMIT_RTPRIO, &r) != 0) {
qCritical("Failed to set priority limits.");
}
}
int ncap = sizeof(caps) / sizeof(cap_value_t);
cap_t c = cap_init();
cap_clear(c);
cap_set_flag(c, CAP_EFFECTIVE, ncap, caps, CAP_SET);
cap_set_flag(c, CAP_PERMITTED, ncap, caps, CAP_SET);
if (cap_set_proc(c) != 0) {
qCritical("Failed to set final capabilities");
} else {
qWarning("Successfully dropped capabilities");
}
cap_free(c);
#endif
}
const QString UnixMurmur::trySystemIniFiles(const QString &fname) {
QString file = fname;
if (!file.isEmpty())
return file;
#if defined(Q_OS_LINUX)
if (!bRoot)
return file;
QStringList inipaths;
inipaths << QLatin1String("/usr/local/etc/mumble-server.ini");
inipaths << QLatin1String("/usr/local/etc/murmur.ini");
inipaths << QLatin1String("/etc/mumble-server.ini");
inipaths << QLatin1String("/etc/murmur.ini");
foreach (const QString &f, inipaths) {
QFileInfo fi(f);
if (fi.exists() && fi.isReadable()) {
file = fi.absoluteFilePath();
break;
}
}
#endif
return file;
}
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