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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 1.58 by root, Sun Jan 22 12:23:55 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>
7 * 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>
8 * 12 *
9 * 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
10 * 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
11 * the Free Software Foundation; either version 2 of the License, or 15 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version. 16 * (at your option) any later version.
… …
19 * You should have received a copy of the GNU General Public License 23 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software 24 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 *---------------------------------------------------------------------*/ 26 *---------------------------------------------------------------------*/
23 27
24#include "../config.h" /* NECESSARY */ 28#include "../config.h"
25 29
26#include "fdpass.h"
27#include "ptytty.h" 30#include "ptytty.h"
28 31
29#include <cstdlib> 32#include <cstdlib>
30#include <cstring> 33#include <cstring>
31 34
… …
232 235
233 ioctl (fd_tty, TIOCSCTTY, NULL); 236 ioctl (fd_tty, TIOCSCTTY, NULL);
234 237
235 int fd = open ("/dev/tty", O_WRONLY); 238 int fd = open ("/dev/tty", O_WRONLY);
236 if (fd < 0) 239 if (fd < 0)
237 return -1; /* fatal */ 240 return -1; /* fatal */
238 241
239 close (fd); 242 close (fd);
240 243
241 return 0; 244 return 0;
242} 245}
… …
370 return true; 373 return true;
371} 374}
372 375
373#if PTYTTY_HELPER 376#if PTYTTY_HELPER
374 377
375static int sock_fd; 378static int sock_fd = -1;
376static int pid; 379static int helper_pid, owner_pid;
377 380
378struct command 381struct command
379{ 382{
380 enum { get, login, destroy } type; 383 enum { get, login, destroy } type;
381 384
… …
409 cmd.type = command::get; 412 cmd.type = command::get;
410 413
411 write (sock_fd, &cmd, sizeof (cmd)); 414 write (sock_fd, &cmd, sizeof (cmd));
412 415
413 if (read (sock_fd, &id, sizeof (id)) != sizeof (id)) 416 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
414 fatal ("protocol error while creating pty using helper process, aborting.\n"); 417 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
415 418
416 if (!id) 419 if (!id)
417 return false; 420 return false;
418 421
419 if ((pty = ptytty_recv_fd (sock_fd)) < 0 422 if ((pty = recv_fd (sock_fd)) < 0
420 || (tty = ptytty_recv_fd (sock_fd)) < 0) 423 || (tty = recv_fd (sock_fd)) < 0)
421 fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n"); 424 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
422 425
423 return true; 426 return true;
424} 427}
425 428
426void 429void
… …
466 if (cmd.id->get ()) 469 if (cmd.id->get ())
467 { 470 {
468 write (sock_fd, &cmd.id, sizeof (cmd.id)); 471 write (sock_fd, &cmd.id, sizeof (cmd.id));
469 ptys.push_back (cmd.id); 472 ptys.push_back (cmd.id);
470 473
471 ptytty_send_fd (sock_fd, cmd.id->pty); 474 ptytty::send_fd (sock_fd, cmd.id->pty);
472 ptytty_send_fd (sock_fd, cmd.id->tty); 475 ptytty::send_fd (sock_fd, cmd.id->tty);
473 } 476 }
474 else 477 else
475 { 478 {
476 delete cmd.id; 479 delete cmd.id;
477 cmd.id = 0; 480 cmd.id = 0;
… …
488 } 491 }
489#endif 492#endif
490 } 493 }
491 else if (cmd.type == command::destroy) 494 else if (cmd.type == command::destroy)
492 { 495 {
493 ptytty **pty = find (ptys.begin (), ptys.end (), cmd.id); 496 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
494 497
495 if (pty) 498 if (pty != ptys.end ())
496 { 499 {
497 delete *pty; 500 delete *pty;
498 ptys.erase (pty); 501 ptys.erase (pty);
499 } 502 }
500 } 503 }
501 else 504 else
502 break; 505 break;
503 } 506 }
504 507
505 // destroy all ptys 508 // destroy all ptys
506 for (ptytty **i = ptys.end (); i-- > ptys.begin (); ) 509 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
507 delete *i; 510 delete *i;
508} 511}
509 512
510void ptytty_server () 513void
514ptytty::use_helper ()
511{ 515{
516 int pid = getpid ();
517
518 if (sock_fd >= 0 && pid == owner_pid)
519 return;
520
521 owner_pid = pid;
522
512 int sv[2]; 523 int sv[2];
513 524
514 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv)) 525 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
515 fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n"); 526 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
516 527
517 pid = fork (); 528 helper_pid = fork ();
518 529
519 if (pid < 0) 530 if (helper_pid < 0)
520 fatal ("could not create pty/sessiondb helper process, aborting.\n"); 531 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
521 532
522 if (pid) 533 if (helper_pid)
523 { 534 {
524 // client, process 535 // client, process
525 sock_fd = sv[0]; 536 sock_fd = sv[0];
526 close (sv[1]); 537 close (sv[1]);
527 fcntl (sock_fd, F_SETFD, FD_CLOEXEC); 538 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
… …
529 else 540 else
530 { 541 {
531 // server, pty-helper 542 // server, pty-helper
532 sock_fd = sv[1]; 543 sock_fd = sv[1];
533 544
545 chdir ("/");
546
534 for (int fd = 0; fd < 1023; fd++) 547 for (int fd = 0; fd < 1023; fd++)
535 if (fd != sock_fd) 548 if (fd != sock_fd)
536 close (fd); 549 close (fd);
537 550
538 serve (); 551 serve ();
… …
540 } 553 }
541} 554}
542 555
543#endif 556#endif
544 557
545// a "factory" *g*
546ptytty * 558ptytty *
547new_ptytty () 559ptytty::create ()
548{ 560{
549#if PTYTTY_HELPER 561#if PTYTTY_HELPER
550 if (pid > 0) 562 if (helper_pid && getpid () == owner_pid)
551 // use helper process 563 // use helper process
552 return new ptytty_proxy; 564 return new ptytty_proxy;
553 else 565 else
554#endif 566#endif
555 return new ptytty_unix; 567 return new ptytty_unix;
556} 568}
557 569
558/*----------------------- end-of-file (C source) -----------------------*/ 570void
571ptytty::init ()
572{
573 uid_t uid = getuid ();
574 gid_t gid = getgid ();
575
576 // before doing anything else, check for setuid/setgid operation,
577 // start the helper process and drop privileges
578 if (uid != geteuid ()
579 || gid != getegid ())
580 {
581#if PTYTTY_HELPER
582 use_helper ();
583#else
584 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
585#endif
559 586
587 drop_privileges ();
588 }
589}
590
591void
592ptytty::drop_privileges ()
593{
594 uid_t uid = getuid ();
595 gid_t gid = getgid ();
596
597 // drop privileges
598#if HAVE_SETRESUID
599 setresgid (gid, gid, gid);
600 setresuid (uid, uid, uid);
601#elif HAVE_SETREUID
602 setregid (gid, gid);
603 setreuid (uid, uid);
604#elif HAVE_SETUID
605 setgid (gid);
606 setuid (uid);
607#endif
608
609 if (uid != geteuid ()
610 || gid != getegid ())
611 ptytty_fatal ("unable to drop privileges, aborting.\n");
612}
613

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