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/cvs/rxvt-unicode/src/ptytty.C
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Comparing rxvt-unicode/src/ptytty.C (file contents):
Revision 1.55 by root, Sun Jan 22 01:00:46 2006 UTC vs.
Revision 1.57 by root, Sun Jan 22 12:21:47 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.
… …
24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 *---------------------------------------------------------------------*/ 26 *---------------------------------------------------------------------*/
26 27
27#include "../config.h" 28#include "../config.h"
28 29
29#include "fdpass.h"
30#include "ptytty.h" 30#include "ptytty.h"
31 31
32#include <cstdlib> 32#include <cstdlib>
33#include <cstring> 33#include <cstring>
34 34
… …
235 235
236 ioctl (fd_tty, TIOCSCTTY, NULL); 236 ioctl (fd_tty, TIOCSCTTY, NULL);
237 237
238 int fd = open ("/dev/tty", O_WRONLY); 238 int fd = open ("/dev/tty", O_WRONLY);
239 if (fd < 0) 239 if (fd < 0)
240 return -1; /* fatal */ 240 return -1; /* fatal */
241 241
242 close (fd); 242 close (fd);
243 243
244 return 0; 244 return 0;
245} 245}
… …
373 return true; 373 return true;
374} 374}
375 375
376#if PTYTTY_HELPER 376#if PTYTTY_HELPER
377 377
378static int sock_fd; 378static int sock_fd = -1;
379static int pid; 379static int helper_pid, owner_pid;
380 380
381struct command 381struct command
382{ 382{
383 enum { get, login, destroy } type; 383 enum { get, login, destroy } type;
384 384
… …
412 cmd.type = command::get; 412 cmd.type = command::get;
413 413
414 write (sock_fd, &cmd, sizeof (cmd)); 414 write (sock_fd, &cmd, sizeof (cmd));
415 415
416 if (read (sock_fd, &id, sizeof (id)) != sizeof (id)) 416 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
417 fatal ("protocol error while creating pty using helper process, aborting.\n"); 417 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
418 418
419 if (!id) 419 if (!id)
420 return false; 420 return false;
421 421
422 if ((pty = ptytty_recv_fd (sock_fd)) < 0 422 if ((pty = recv_fd (sock_fd)) < 0
423 || (tty = ptytty_recv_fd (sock_fd)) < 0) 423 || (tty = recv_fd (sock_fd)) < 0)
424 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");
425 425
426 return true; 426 return true;
427} 427}
428 428
429void 429void
… …
469 if (cmd.id->get ()) 469 if (cmd.id->get ())
470 { 470 {
471 write (sock_fd, &cmd.id, sizeof (cmd.id)); 471 write (sock_fd, &cmd.id, sizeof (cmd.id));
472 ptys.push_back (cmd.id); 472 ptys.push_back (cmd.id);
473 473
474 ptytty_send_fd (sock_fd, cmd.id->pty); 474 ptytty::send_fd (sock_fd, cmd.id->pty);
475 ptytty_send_fd (sock_fd, cmd.id->tty); 475 ptytty::send_fd (sock_fd, cmd.id->tty);
476 } 476 }
477 else 477 else
478 { 478 {
479 delete cmd.id; 479 delete cmd.id;
480 cmd.id = 0; 480 cmd.id = 0;
… …
491 } 491 }
492#endif 492#endif
493 } 493 }
494 else if (cmd.type == command::destroy) 494 else if (cmd.type == command::destroy)
495 { 495 {
496 ptytty **pty = find (ptys.begin (), ptys.end (), cmd.id); 496 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
497 497
498 if (pty) 498 if (pty != ptys.end ())
499 { 499 {
500 delete *pty; 500 delete *pty;
501 ptys.erase (pty); 501 ptys.erase (pty);
502 } 502 }
503 } 503 }
504 else 504 else
505 break; 505 break;
506 } 506 }
507 507
508 // destroy all ptys 508 // destroy all ptys
509 for (ptytty **i = ptys.end (); i-- > ptys.begin (); ) 509 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
510 delete *i; 510 delete *i;
511} 511}
512 512
513void ptytty_server () 513void
514ptytty::use_helper ()
514{ 515{
516 int pid = getpid ();
517
518 if (sock_fd >= 0 && pid == owner_pid)
519 return;
520
521 owner_pid = pid;
522
515 int sv[2]; 523 int sv[2];
516 524
517 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv)) 525 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
518 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");
519 527
520 pid = fork (); 528 helper_pid = fork ();
521 529
522 if (pid < 0) 530 if (helper_pid < 0)
523 fatal ("could not create pty/sessiondb helper process, aborting.\n"); 531 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
524 532
525 if (pid) 533 if (helper_pid)
526 { 534 {
527 // client, process 535 // client, process
528 sock_fd = sv[0]; 536 sock_fd = sv[0];
529 close (sv[1]); 537 close (sv[1]);
530 fcntl (sock_fd, F_SETFD, FD_CLOEXEC); 538 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
… …
532 else 540 else
533 { 541 {
534 // server, pty-helper 542 // server, pty-helper
535 sock_fd = sv[1]; 543 sock_fd = sv[1];
536 544
545 chdir ("/");
546
537 for (int fd = 0; fd < 1023; fd++) 547 for (int fd = 0; fd < 1023; fd++)
538 if (fd != sock_fd) 548 if (fd != sock_fd)
539 close (fd); 549 close (fd);
540 550
541 serve (); 551 serve ();
… …
543 } 553 }
544} 554}
545 555
546#endif 556#endif
547 557
548// a "factory" *g*
549ptytty * 558ptytty *
550new_ptytty () 559ptytty::create ()
551{ 560{
552#if PTYTTY_HELPER 561#if PTYTTY_HELPER
553 if (pid > 0) 562 if (helper_pid && getpid () == owner_pid)
554 // use helper process 563 // use helper process
555 return new ptytty_proxy; 564 return new ptytty_proxy;
556 else 565 else
557#endif 566#endif
558 return new ptytty_unix; 567 return new ptytty_unix;
559} 568}
560 569
561/*----------------------- 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
562 586
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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