summaryrefslogtreecommitdiffstats
path: root/kdesu/kdesud/kdesud.cpp
blob: d81b6a0c9e7aef8ce6e4e0c196ee15f46e5170b0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
/* 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/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 <qptrvector.h>
#include <qfile.h>
#include <qregexp.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";
QCString 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;

    QCString display(getenv("DISPLAY"));
    if (display.isEmpty())
    {
        kdWarning(1205) << "$DISPLAY is not set\n";
        return -1;
    }

    // strip the screen number from the display
    display.replace(QRegExp("\\.[0-9]+$"), "");

    sock = QFile::encodeName(locateLocal("socket", QString("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[])
{
    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;
    QPtrVector<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";
}