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tdebase/kdesu/kdesud/kdesud.cpp

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/* vi: ts=8 sts=4 sw=4
*
* This file is part of the KDE project, module kdesu.
* Copyright (C) 1999,2000 Geert Jansen <jansen@kde.org>
*
*
* kdesud.cpp: KDE su daemon. Offers "keep password" functionality to kde su.
*
* The socket $KDEHOME/socket-$(HOSTNAME)/kdesud_$(display) is used for communication with
* client programs.
*
* The protocol: Client initiates the connection. All commands and responses
* are terminated by a newline.
*
* Client Server Description
* ------ ------ -----------
*
* PASS <pass> <timeout> OK Set password for commands in
* this session. Password is
* valid for <timeout> seconds.
*
* USER <user> OK Set the target user [required]
*
* EXEC <command> OK Execute command <command>. If
* NO <command> has been executed
* before (< timeout) no PASS
* command is needed.
*
* DEL <command> OK Delete password for command
* NO <command>.
*
* PING OK Ping the server (diagnostics).
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <string.h>
#include <stdarg.h>
#include <signal.h>
#include <pwd.h>
#include <errno.h>
#include <sys/prctl.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/resource.h>
#include <sys/wait.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h> // Needed on some systems.
#endif
#include <tqptrvector.h>
#include <tqfile.h>
#include <tqregexp.h>
#include <kinstance.h>
#include <kdebug.h>
#include <klocale.h>
#include <kcmdlineargs.h>
#include <kstandarddirs.h>
#include <kaboutdata.h>
#include <kdesu/client.h>
#include <kdesu/defaults.h>
#include <ksockaddr.h>
#include "repo.h"
#include "handler.h"
#include <X11/X.h>
#include <X11/Xlib.h>
#ifndef SUN_LEN
#define SUN_LEN(ptr) ((kde_socklen_t) (((struct sockaddr_un *) 0)->sun_path) \
+ strlen ((ptr)->sun_path))
#endif
#define ERR strerror(errno)
// Globals
Repository *repo;
const char *Version = "1.01";
TQCString sock;
Display *x11Display;
int pipeOfDeath[2];
void kdesud_cleanup()
{
unlink(sock);
}
// Borrowed from kdebase/kaudio/kaudioserver.cpp
extern "C" int xio_errhandler(Display *);
int xio_errhandler(Display *)
{
kdError(1205) << "Fatal IO error, exiting...\n";
kdesud_cleanup();
exit(1);
return 1; //silence compilers
}
int initXconnection()
{
x11Display = XOpenDisplay(NULL);
if (x11Display != 0L)
{
XSetIOErrorHandler(xio_errhandler);
XCreateSimpleWindow(x11Display, DefaultRootWindow(x11Display),
0, 0, 1, 1, 0,
BlackPixelOfScreen(DefaultScreenOfDisplay(x11Display)),
BlackPixelOfScreen(DefaultScreenOfDisplay(x11Display)));
return XConnectionNumber(x11Display);
} else
{
kdWarning(1205) << "Can't connect to the X Server.\n";
kdWarning(1205) << "Might not terminate at end of session.\n";
return -1;
}
}
extern "C" {
void signal_exit(int);
void sigchld_handler(int);
}
void signal_exit(int sig)
{
kdDebug(1205) << "Exiting on signal " << sig << "\n";
kdesud_cleanup();
exit(1);
}
void sigchld_handler(int)
{
char c = ' ';
write(pipeOfDeath[1], &c, 1);
}
/**
* Creates an AF_UNIX socket in socket resource, mode 0600.
*/
int create_socket()
{
int sockfd;
ksocklen_t addrlen;
struct stat s;
TQCString display(getenv("DISPLAY"));
if (display.isEmpty())
{
kdWarning(1205) << "$DISPLAY is not set\n";
return -1;
}
// strip the screen number from the display
display.replace(TQRegExp("\\.[0-9]+$"), "");
sock = TQFile::encodeName(locateLocal("socket", TQString("kdesud_%1").arg(display)));
int stat_err=lstat(sock, &s);
if(!stat_err && S_ISLNK(s.st_mode)) {
kdWarning(1205) << "Someone is running a symlink attack on you\n";
if(unlink(sock)) {
kdWarning(1205) << "Could not delete symlink\n";
return -1;
}
}
if (!access(sock, R_OK|W_OK))
{
KDEsuClient client;
if (client.ping() == -1)
{
kdWarning(1205) << "stale socket exists\n";
if (unlink(sock))
{
kdWarning(1205) << "Could not delete stale socket\n";
return -1;
}
} else
{
kdWarning(1205) << "kdesud is already running\n";
return -1;
}
}
sockfd = socket(PF_UNIX, SOCK_STREAM, 0);
if (sockfd < 0)
{
kdError(1205) << "socket(): " << ERR << "\n";
return -1;
}
struct sockaddr_un addr;
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path, sock, sizeof(addr.sun_path)-1);
addr.sun_path[sizeof(addr.sun_path)-1] = '\000';
addrlen = SUN_LEN(&addr);
if (bind(sockfd, (struct sockaddr *)&addr, addrlen) < 0)
{
kdError(1205) << "bind(): " << ERR << "\n";
return -1;
}
struct linger lin;
lin.l_onoff = lin.l_linger = 0;
if (setsockopt(sockfd, SOL_SOCKET, SO_LINGER, (char *) &lin,
sizeof(linger)) < 0)
{
kdError(1205) << "setsockopt(SO_LINGER): " << ERR << "\n";
return -1;
}
int opt = 1;
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char *) &opt,
sizeof(opt)) < 0)
{
kdError(1205) << "setsockopt(SO_REUSEADDR): " << ERR << "\n";
return -1;
}
opt = 1;
if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, (char *) &opt,
sizeof(opt)) < 0)
{
kdError(1205) << "setsockopt(SO_KEEPALIVE): " << ERR << "\n";
return -1;
}
chmod(sock, 0600);
return sockfd;
}
/**
* Main program
*/
int main(int argc, char *argv[])
{
prctl(PR_SET_DUMPABLE, 0);
KAboutData aboutData("kdesud", I18N_NOOP("KDE su daemon"),
Version, I18N_NOOP("Daemon used by kdesu"),
KAboutData::License_Artistic,
"Copyright (c) 1999,2000 Geert Jansen");
aboutData.addAuthor("Geert Jansen", I18N_NOOP("Author"),
"jansen@kde.org", "http://www.stack.nl/~geertj/");
KCmdLineArgs::init(argc, argv, &aboutData);
KInstance instance(&aboutData);
// Set core dump size to 0
struct rlimit rlim;
rlim.rlim_cur = rlim.rlim_max = 0;
if (setrlimit(RLIMIT_CORE, &rlim) < 0)
{
kdError(1205) << "setrlimit(): " << ERR << "\n";
exit(1);
}
// Create the Unix socket.
int sockfd = create_socket();
if (sockfd < 0)
exit(1);
if (listen(sockfd, 1) < 0)
{
kdError(1205) << "listen(): " << ERR << "\n";
kdesud_cleanup();
exit(1);
}
int maxfd = sockfd;
// Ok, we're accepting connections. Fork to the background.
pid_t pid = fork();
if (pid == -1)
{
kdError(1205) << "fork():" << ERR << "\n";
kdesud_cleanup();
exit(1);
}
if (pid)
exit(0);
// Make sure we exit when the display gets closed.
int x11Fd = initXconnection();
maxfd = QMAX(maxfd, x11Fd);
repo = new Repository;
TQPtrVector<ConnectionHandler> handler;
handler.setAutoDelete(true);
pipe(pipeOfDeath);
maxfd = QMAX(maxfd, pipeOfDeath[0]);
// Signal handlers
struct sigaction sa;
sa.sa_handler = signal_exit;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(SIGHUP, &sa, 0L);
sigaction(SIGINT, &sa, 0L);
sigaction(SIGTERM, &sa, 0L);
sigaction(SIGQUIT, &sa, 0L);
sa.sa_handler = sigchld_handler;
sa.sa_flags = SA_NOCLDSTOP;
sigaction(SIGCHLD, &sa, 0L);
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, 0L);
// Main execution loop
ksocklen_t addrlen;
struct sockaddr_un clientname;
fd_set tmp_fds, active_fds;
FD_ZERO(&active_fds);
FD_SET(sockfd, &active_fds);
FD_SET(pipeOfDeath[0], &active_fds);
if (x11Fd != -1)
FD_SET(x11Fd, &active_fds);
while (1)
{
tmp_fds = active_fds;
if(x11Display)
XFlush(x11Display);
if (select(maxfd+1, &tmp_fds, 0L, 0L, 0L) < 0)
{
if (errno == EINTR) continue;
kdError(1205) << "select(): " << ERR << "\n";
exit(1);
}
repo->expire();
for (int i=0; i<=maxfd; i++)
{
if (!FD_ISSET(i, &tmp_fds))
continue;
if (i == pipeOfDeath[0])
{
char buf[101];
read(pipeOfDeath[0], buf, 100);
pid_t result;
do
{
int status;
result = waitpid((pid_t)-1, &status, WNOHANG);
if (result > 0)
{
for(int j=handler.size(); j--;)
{
if (handler[j] && (handler[j]->m_pid == result))
{
handler[j]->m_exitCode = WEXITSTATUS(status);
handler[j]->m_hasExitCode = true;
handler[j]->sendExitCode();
handler[j]->m_pid = 0;
break;
}
}
}
}
while(result > 0);
}
if (i == x11Fd)
{
// Discard X events
XEvent event_return;
if (x11Display)
while(XPending(x11Display))
XNextEvent(x11Display, &event_return);
continue;
}
if (i == sockfd)
{
// Accept new connection
int fd;
addrlen = 64;
fd = accept(sockfd, (struct sockaddr *) &clientname, &addrlen);
if (fd < 0)
{
kdError(1205) << "accept():" << ERR << "\n";
continue;
}
if (fd+1 > (int) handler.size())
handler.resize(fd+1);
handler.insert(fd, new ConnectionHandler(fd));
maxfd = QMAX(maxfd, fd);
FD_SET(fd, &active_fds);
continue;
}
// handle alreay established connection
if (handler[i] && handler[i]->handle() < 0)
{
handler.remove(i);
FD_CLR(i, &active_fds);
}
}
}
kdWarning(1205) << "???\n";
}