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Comparing rxvt-unicode/src/ptytty.C (file contents):
Revision 1.54 by root, Sun Jan 22 00:48:13 2006 UTC vs.
Revision 1.56 by root, Sun Jan 22 04:01:52 2006 UTC

1// This file is part of libptytty. Do not make local modifications.
2// http://software.schmorp.de/pkg/libptytty
3
1/*--------------------------------*-C-*---------------------------------* 4/*----------------------------------------------------------------------*
2 * File: ptytty.C 5 * File: ptytty.C
3 *----------------------------------------------------------------------* 6 *----------------------------------------------------------------------*
4 * 7 *
5 * All portions of code are copyright by their respective author/s. 8 * All portions of code are copyright by their respective author/s.
6 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com> 9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com>
… …
19 * You should have received a copy of the GNU General Public License 22 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software 23 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 *---------------------------------------------------------------------*/ 25 *---------------------------------------------------------------------*/
23 26
24#include "../config.h" /* NECESSARY */ 27#include "../config.h"
25 28
26#include "fdpass.h"
27#include "ptytty.h" 29#include "ptytty.h"
28 30
29#include <cstdlib> 31#include <cstdlib>
30#include <cstring> 32#include <cstring>
31 33
… …
232 234
233 ioctl (fd_tty, TIOCSCTTY, NULL); 235 ioctl (fd_tty, TIOCSCTTY, NULL);
234 236
235 int fd = open ("/dev/tty", O_WRONLY); 237 int fd = open ("/dev/tty", O_WRONLY);
236 if (fd < 0) 238 if (fd < 0)
237 return -1; /* fatal */ 239 return -1; /* fatal */
238 240
239 close (fd); 241 close (fd);
240 242
241 return 0; 243 return 0;
242} 244}
… …
370 return true; 372 return true;
371} 373}
372 374
373#if PTYTTY_HELPER 375#if PTYTTY_HELPER
374 376
375static int sock_fd; 377static int sock_fd = -1;
376static int pid; 378static int helper_pid, owner_pid;
377 379
378struct command 380struct command
379{ 381{
380 enum { get, login, destroy } type; 382 enum { get, login, destroy } type;
381 383
… …
409 cmd.type = command::get; 411 cmd.type = command::get;
410 412
411 write (sock_fd, &cmd, sizeof (cmd)); 413 write (sock_fd, &cmd, sizeof (cmd));
412 414
413 if (read (sock_fd, &id, sizeof (id)) != sizeof (id)) 415 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
414 fatal ("protocol error while creating pty using helper process, aborting.\n"); 416 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
415 417
416 if (!id) 418 if (!id)
417 return false; 419 return false;
418 420
419 if ((pty = ptytty_recv_fd (sock_fd)) < 0 421 if ((pty = recv_fd (sock_fd)) < 0
420 || (tty = ptytty_recv_fd (sock_fd)) < 0) 422 || (tty = recv_fd (sock_fd)) < 0)
421 fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n"); 423 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
422 424
423 return true; 425 return true;
424} 426}
425 427
426void 428void
… …
466 if (cmd.id->get ()) 468 if (cmd.id->get ())
467 { 469 {
468 write (sock_fd, &cmd.id, sizeof (cmd.id)); 470 write (sock_fd, &cmd.id, sizeof (cmd.id));
469 ptys.push_back (cmd.id); 471 ptys.push_back (cmd.id);
470 472
471 ptytty_send_fd (sock_fd, cmd.id->pty); 473 ptytty::send_fd (sock_fd, cmd.id->pty);
472 ptytty_send_fd (sock_fd, cmd.id->tty); 474 ptytty::send_fd (sock_fd, cmd.id->tty);
473 } 475 }
474 else 476 else
475 { 477 {
476 delete cmd.id; 478 delete cmd.id;
477 cmd.id = 0; 479 cmd.id = 0;
… …
488 } 490 }
489#endif 491#endif
490 } 492 }
491 else if (cmd.type == command::destroy) 493 else if (cmd.type == command::destroy)
492 { 494 {
493 ptytty **pty = find (ptys.begin (), ptys.end (), cmd.id); 495 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
494 496
495 if (pty) 497 if (pty != ptys.end ())
496 { 498 {
497 delete *pty; 499 delete *pty;
498 ptys.erase (pty); 500 ptys.erase (pty);
499 } 501 }
500 } 502 }
501 else 503 else
502 break; 504 break;
503 } 505 }
504 506
505 // destroy all ptys 507 // destroy all ptys
506 for (ptytty **i = ptys.end (); i-- > ptys.begin (); ) 508 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
507 delete *i; 509 delete *i;
508} 510}
509 511
510void ptytty_server () 512void
513ptytty::use_helper ()
511{ 514{
515 int pid = getpid ();
516
517 if (sock_fd >= 0 && pid == owner_pid)
518 return;
519
520 owner_pid = pid;
521
512 int sv[2]; 522 int sv[2];
513 523
514 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv)) 524 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
515 fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n"); 525 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
516 526
517 pid = fork (); 527 helper_pid = fork ();
518 528
519 if (pid < 0) 529 if (helper_pid < 0)
520 fatal ("could not create pty/sessiondb helper process, aborting.\n"); 530 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
521 531
522 if (pid) 532 if (helper_pid)
523 { 533 {
524 // client, process 534 // client, process
525 sock_fd = sv[0]; 535 sock_fd = sv[0];
526 close (sv[1]); 536 close (sv[1]);
527 fcntl (sock_fd, F_SETFD, FD_CLOEXEC); 537 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
… …
529 else 539 else
530 { 540 {
531 // server, pty-helper 541 // server, pty-helper
532 sock_fd = sv[1]; 542 sock_fd = sv[1];
533 543
544 chdir ("/");
545
534 for (int fd = 0; fd < 1023; fd++) 546 for (int fd = 0; fd < 1023; fd++)
535 if (fd != sock_fd) 547 if (fd != sock_fd)
536 close (fd); 548 close (fd);
537 549
538 serve (); 550 serve ();
… …
540 } 552 }
541} 553}
542 554
543#endif 555#endif
544 556
545// a "factory" *g*
546ptytty * 557ptytty *
547new_ptytty () 558ptytty::create ()
548{ 559{
549#if PTYTTY_HELPER 560#if PTYTTY_HELPER
550 if (pid > 0) 561 if (helper_pid && getpid () == owner_pid)
551 // use helper process 562 // use helper process
552 return new ptytty_proxy; 563 return new ptytty_proxy;
553 else 564 else
554#endif 565#endif
555 return new ptytty_unix; 566 return new ptytty_unix;
556} 567}
557 568
558/*----------------------- end-of-file (C source) -----------------------*/ 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
559 585
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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