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Comparing rxvt-unicode/src/ptytty.C (file contents):
Revision 1.56 by root, Sun Jan 22 04:01:52 2006 UTC vs.
Revision 1.61 by root, Wed Jan 25 10:51:26 2006 UTC

… …
6 *----------------------------------------------------------------------* 6 *----------------------------------------------------------------------*
7 * 7 *
8 * All portions of code are copyright by their respective author/s. 8 * All portions of code are copyright by their respective author/s.
9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com> 9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com>
10 * Copyright (c) 2004-2006 Marc Lehmann <pcg@goof.com> 10 * Copyright (c) 2004-2006 Marc Lehmann <pcg@goof.com>
11 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it>
11 * 12 *
12 * This program is free software; you can redistribute it and/or modify 13 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by 14 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or 15 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version. 16 * (at your option) any later version.
… …
28 29
29#include "ptytty.h" 30#include "ptytty.h"
30 31
31#include <cstdlib> 32#include <cstdlib>
32#include <cstring> 33#include <cstring>
34#include <csignal>
33 35
34#include <sys/types.h> 36#include <sys/types.h>
35#include <sys/socket.h>
36#include <unistd.h> 37#include <unistd.h>
37#include <fcntl.h> 38#include <fcntl.h>
38 39
39#ifdef HAVE_SYS_IOCTL_H 40#ifdef HAVE_SYS_IOCTL_H
40# include <sys/ioctl.h> 41# include <sys/ioctl.h>
… …
370 } 371 }
371 372
372 return true; 373 return true;
373} 374}
374 375
375#if PTYTTY_HELPER
376
377static int sock_fd = -1;
378static int helper_pid, owner_pid;
379
380struct command
381{
382 enum { get, login, destroy } type;
383
384 ptytty *id;
385
386 bool login_shell;
387 int cmd_pid;
388 char hostname[512]; // arbitrary, but should be plenty
389};
390
391struct ptytty_proxy : ptytty
392{
393 ptytty *id;
394
395 ptytty_proxy ()
396 : id(0)
397 {
398 }
399
400 ~ptytty_proxy ();
401
402 bool get ();
403 void login (int cmd_pid, bool login_shell, const char *hostname);
404};
405
406bool
407ptytty_proxy::get ()
408{
409 command cmd;
410
411 cmd.type = command::get;
412
413 write (sock_fd, &cmd, sizeof (cmd));
414
415 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
416 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
417
418 if (!id)
419 return false;
420
421 if ((pty = recv_fd (sock_fd)) < 0
422 || (tty = recv_fd (sock_fd)) < 0)
423 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
424
425 return true;
426}
427
428void
429ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
430{
431 command cmd;
432
433 cmd.type = command::login;
434 cmd.id = id;
435 cmd.cmd_pid = cmd_pid;
436 cmd.login_shell = login_shell;
437 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
438
439 write (sock_fd, &cmd, sizeof (cmd));
440}
441
442ptytty_proxy::~ptytty_proxy ()
443{
444 if (id)
445 {
446 command cmd;
447
448 cmd.type = command::destroy;
449 cmd.id = id;
450
451 write (sock_fd, &cmd, sizeof (cmd));
452 }
453}
454
455static
456void serve ()
457{
458 command cmd;
459 vector<ptytty *> ptys;
460
461 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
462 {
463 if (cmd.type == command::get)
464 {
465 // -> id ptyfd ttyfd
466 cmd.id = new ptytty_unix;
467
468 if (cmd.id->get ())
469 {
470 write (sock_fd, &cmd.id, sizeof (cmd.id));
471 ptys.push_back (cmd.id);
472
473 ptytty::send_fd (sock_fd, cmd.id->pty);
474 ptytty::send_fd (sock_fd, cmd.id->tty);
475 }
476 else
477 {
478 delete cmd.id;
479 cmd.id = 0;
480 write (sock_fd, &cmd.id, sizeof (cmd.id));
481 }
482 }
483 else if (cmd.type == command::login)
484 {
485#if UTMP_SUPPORT
486 if (find (ptys.begin (), ptys.end (), cmd.id))
487 {
488 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
489 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
490 }
491#endif
492 }
493 else if (cmd.type == command::destroy)
494 {
495 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
496
497 if (pty != ptys.end ())
498 {
499 delete *pty;
500 ptys.erase (pty);
501 }
502 }
503 else
504 break;
505 }
506
507 // destroy all ptys
508 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
509 delete *i;
510}
511
512void
513ptytty::use_helper ()
514{
515 int pid = getpid ();
516
517 if (sock_fd >= 0 && pid == owner_pid)
518 return;
519
520 owner_pid = pid;
521
522 int sv[2];
523
524 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
525 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
526
527 helper_pid = fork ();
528
529 if (helper_pid < 0)
530 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
531
532 if (helper_pid)
533 {
534 // client, process
535 sock_fd = sv[0];
536 close (sv[1]);
537 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
538 }
539 else
540 {
541 // server, pty-helper
542 sock_fd = sv[1];
543
544 chdir ("/");
545
546 for (int fd = 0; fd < 1023; fd++)
547 if (fd != sock_fd)
548 close (fd);
549
550 serve ();
551 _exit (EXIT_SUCCESS);
552 }
553}
554
555#endif
556
557ptytty *
558ptytty::create ()
559{
560#if PTYTTY_HELPER
561 if (helper_pid && getpid () == owner_pid)
562 // use helper process
563 return new ptytty_proxy;
564 else
565#endif
566 return new ptytty_unix;
567}
568
569void
570ptytty::init ()
571{
572 uid_t uid = getuid ();
573 gid_t gid = getgid ();
574
575 // before doing anything else, check for setuid/setgid operation,
576 // start the helper process and drop privileges
577 if (uid != geteuid ()
578 || gid != getegid ())
579 {
580#if PTYTTY_HELPER
581 use_helper ();
582#else
583 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
584#endif
585
586 drop_privileges ();
587 }
588}
589
590void
591ptytty::drop_privileges ()
592{
593 uid_t uid = getuid ();
594 gid_t gid = getgid ();
595
596 // drop privileges
597#if HAVE_SETRESUID
598 setresgid (gid, gid, gid);
599 setresuid (uid, uid, uid);
600#elif HAVE_SETREUID
601 setregid (gid, gid);
602 setreuid (uid, uid);
603#elif HAVE_SETUID
604 setgid (gid);
605 setuid (uid);
606#endif
607
608 if (uid != geteuid ()
609 || gid != getegid ())
610 ptytty_fatal ("unable to drop privileges, aborting.\n");
611}
612

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