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1 | // This file is part of libptytty. Do not make local modifications. |
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2 | // http://software.schmorp.de/pkg/libptytty |
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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> |
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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" |
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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 | } |
… | |
… | |
368 | } |
371 | } |
369 | |
372 | |
370 | return true; |
373 | return true; |
371 | } |
374 | } |
372 | |
375 | |
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376 | ///////////////////////////////////////////////////////////////////////////// |
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377 | // helper/proxy support |
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378 | |
373 | #if PTYTTY_HELPER |
379 | #if PTYTTY_HELPER |
374 | |
380 | |
375 | static int sock_fd; |
381 | static int sock_fd = -1; |
376 | static int pid; |
382 | static int helper_pid, owner_pid; |
377 | |
383 | |
378 | struct command |
384 | struct command |
379 | { |
385 | { |
380 | enum { get, login, destroy } type; |
386 | enum { get, login, destroy } type; |
381 | |
387 | |
… | |
… | |
388 | |
394 | |
389 | struct ptytty_proxy : ptytty |
395 | struct ptytty_proxy : ptytty |
390 | { |
396 | { |
391 | ptytty *id; |
397 | ptytty *id; |
392 | |
398 | |
393 | ~ptytty_proxy () |
399 | ptytty_proxy () |
394 | : id(0) |
400 | : id(0) |
395 | { |
401 | { |
396 | } |
402 | } |
397 | |
403 | |
398 | ~ptytty_proxy (); |
404 | ~ptytty_proxy (); |
… | |
… | |
409 | cmd.type = command::get; |
415 | cmd.type = command::get; |
410 | |
416 | |
411 | write (sock_fd, &cmd, sizeof (cmd)); |
417 | write (sock_fd, &cmd, sizeof (cmd)); |
412 | |
418 | |
413 | if (read (sock_fd, &id, sizeof (id)) != sizeof (id)) |
419 | if (read (sock_fd, &id, sizeof (id)) != sizeof (id)) |
414 | fatal ("protocol error while creating pty using helper process, aborting.\n"); |
420 | ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n"); |
415 | |
421 | |
416 | if (!id) |
422 | if (!id) |
417 | return false; |
423 | return false; |
418 | |
424 | |
419 | if ((pty = ptytty_recv_fd (sock_fd)) < 0 |
425 | if ((pty = recv_fd (sock_fd)) < 0 |
420 | || (tty = ptytty_recv_fd (sock_fd)) < 0) |
426 | || (tty = recv_fd (sock_fd)) < 0) |
421 | fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n"); |
427 | ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n"); |
422 | |
428 | |
423 | return true; |
429 | return true; |
424 | } |
430 | } |
425 | |
431 | |
426 | void |
432 | void |
… | |
… | |
466 | if (cmd.id->get ()) |
472 | if (cmd.id->get ()) |
467 | { |
473 | { |
468 | write (sock_fd, &cmd.id, sizeof (cmd.id)); |
474 | write (sock_fd, &cmd.id, sizeof (cmd.id)); |
469 | ptys.push_back (cmd.id); |
475 | ptys.push_back (cmd.id); |
470 | |
476 | |
471 | ptytty_send_fd (sock_fd, cmd.id->pty); |
477 | ptytty::send_fd (sock_fd, cmd.id->pty); |
472 | ptytty_send_fd (sock_fd, cmd.id->tty); |
478 | ptytty::send_fd (sock_fd, cmd.id->tty); |
473 | } |
479 | } |
474 | else |
480 | else |
475 | { |
481 | { |
476 | delete cmd.id; |
482 | delete cmd.id; |
477 | cmd.id = 0; |
483 | cmd.id = 0; |
… | |
… | |
479 | } |
485 | } |
480 | } |
486 | } |
481 | else if (cmd.type == command::login) |
487 | else if (cmd.type == command::login) |
482 | { |
488 | { |
483 | #if UTMP_SUPPORT |
489 | #if UTMP_SUPPORT |
484 | if (find (ptys.begin (), ptys.end (), cmd.id)) |
490 | if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ()) |
485 | { |
491 | { |
486 | cmd.hostname[sizeof (cmd.hostname) - 1] = 0; |
492 | cmd.hostname[sizeof (cmd.hostname) - 1] = 0; |
487 | cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname); |
493 | cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname); |
488 | } |
494 | } |
489 | #endif |
495 | #endif |
490 | } |
496 | } |
491 | else if (cmd.type == command::destroy) |
497 | else if (cmd.type == command::destroy) |
492 | { |
498 | { |
493 | ptytty **pty = find (ptys.begin (), ptys.end (), cmd.id); |
499 | vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id); |
494 | |
500 | |
495 | if (pty) |
501 | if (pty != ptys.end ()) |
496 | { |
502 | { |
497 | delete *pty; |
503 | delete *pty; |
498 | ptys.erase (pty); |
504 | ptys.erase (pty); |
499 | } |
505 | } |
500 | } |
506 | } |
501 | else |
507 | else |
502 | break; |
508 | break; |
503 | } |
509 | } |
504 | |
510 | |
505 | // destroy all ptys |
511 | // destroy all ptys |
506 | for (ptytty **i = ptys.end (); i-- > ptys.begin (); ) |
512 | for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); ) |
507 | delete *i; |
513 | delete *i; |
508 | } |
514 | } |
509 | |
515 | |
510 | void ptytty_server () |
516 | void |
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517 | ptytty::use_helper () |
511 | { |
518 | { |
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519 | int pid = getpid (); |
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520 | |
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521 | if (sock_fd >= 0 && pid == owner_pid) |
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522 | return; |
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523 | |
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524 | owner_pid = pid; |
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525 | |
512 | int sv[2]; |
526 | int sv[2]; |
513 | |
527 | |
514 | if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv)) |
528 | if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv)) |
515 | fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n"); |
529 | ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n"); |
516 | |
530 | |
517 | pid = fork (); |
531 | helper_pid = fork (); |
518 | |
532 | |
519 | if (pid < 0) |
533 | if (helper_pid < 0) |
520 | fatal ("could not create pty/sessiondb helper process, aborting.\n"); |
534 | ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n"); |
521 | |
535 | |
522 | if (pid) |
536 | if (helper_pid) |
523 | { |
537 | { |
524 | // client, process |
538 | // client, process |
525 | sock_fd = sv[0]; |
539 | sock_fd = sv[0]; |
526 | close (sv[1]); |
540 | close (sv[1]); |
527 | fcntl (sock_fd, F_SETFD, FD_CLOEXEC); |
541 | fcntl (sock_fd, F_SETFD, FD_CLOEXEC); |
… | |
… | |
529 | else |
543 | else |
530 | { |
544 | { |
531 | // server, pty-helper |
545 | // server, pty-helper |
532 | sock_fd = sv[1]; |
546 | sock_fd = sv[1]; |
533 | |
547 | |
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548 | chdir ("/"); |
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549 | |
534 | for (int fd = 0; fd < 1023; fd++) |
550 | for (int fd = 0; fd < 1023; fd++) |
535 | if (fd != sock_fd) |
551 | if (fd != sock_fd) |
536 | close (fd); |
552 | close (fd); |
537 | |
553 | |
538 | serve (); |
554 | serve (); |
… | |
… | |
540 | } |
556 | } |
541 | } |
557 | } |
542 | |
558 | |
543 | #endif |
559 | #endif |
544 | |
560 | |
545 | // a "factory" *g* |
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546 | ptytty * |
561 | ptytty * |
547 | new_ptytty () |
562 | ptytty::create () |
548 | { |
563 | { |
549 | #if PTYTTY_HELPER |
564 | #if PTYTTY_HELPER |
550 | if (pid > 0) |
565 | if (helper_pid && getpid () == owner_pid) |
551 | // use helper process |
566 | // use helper process |
552 | return new ptytty_proxy; |
567 | return new ptytty_proxy; |
553 | else |
568 | else |
554 | #endif |
569 | #endif |
555 | return new ptytty_unix; |
570 | return new ptytty_unix; |
556 | } |
571 | } |
557 | |
572 | |
558 | /*----------------------- end-of-file (C source) -----------------------*/ |
573 | void |
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574 | ptytty::init () |
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575 | { |
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576 | uid_t uid = getuid (); |
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577 | gid_t gid = getgid (); |
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578 | |
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579 | // before doing anything else, check for setuid/setgid operation, |
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580 | // start the helper process and drop privileges |
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581 | if (uid != geteuid () |
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582 | || gid != getegid ()) |
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583 | { |
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584 | #if PTYTTY_HELPER |
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585 | use_helper (); |
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586 | #else |
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587 | ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n"); |
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588 | #endif |
559 | |
589 | |
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590 | drop_privileges (); |
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591 | } |
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592 | } |
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593 | |
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594 | void |
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595 | ptytty::drop_privileges () |
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596 | { |
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597 | uid_t uid = getuid (); |
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598 | gid_t gid = getgid (); |
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599 | |
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600 | // drop privileges |
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601 | #if HAVE_SETRESUID |
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602 | setresgid (gid, gid, gid); |
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603 | setresuid (uid, uid, uid); |
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604 | #elif HAVE_SETREUID |
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605 | setregid (gid, gid); |
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606 | setreuid (uid, uid); |
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607 | #elif HAVE_SETUID |
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608 | setgid (gid); |
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609 | setuid (uid); |
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610 | #endif |
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611 | |
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612 | if (uid != geteuid () |
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613 | || gid != getegid ()) |
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614 | ptytty_fatal ("unable to drop privileges, aborting.\n"); |
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615 | } |
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616 | |
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617 | ///////////////////////////////////////////////////////////////////////////// |
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618 | // C API |
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619 | |
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620 | #ifndef NO_C_API |
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621 | |
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622 | #define DEFINE_METHOD(retval, name, args1, args2) \ |
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623 | extern "C" retval ptytty_ ## name args1 \ |
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624 | { return ((struct ptytty *)ptytty)->name args2; } |
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625 | |
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626 | DEFINE_METHOD(int,pty,(void *ptytty),) |
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627 | DEFINE_METHOD(int,tty,(void *ptytty),) |
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628 | DEFINE_METHOD(int,get,(void *ptytty),()) |
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629 | DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname)) |
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630 | |
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631 | DEFINE_METHOD(void,close_tty,(void *ptytty),()) |
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632 | DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),()) |
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633 | DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on)) |
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634 | |
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635 | #define DEFINE_STATIC(retval, name, args) \ |
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636 | extern "C" retval ptytty_ ## name args \ |
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637 | { return ptytty::name args; } |
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638 | |
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639 | DEFINE_STATIC(void,drop_privileges,()) |
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640 | DEFINE_STATIC(void,use_helper,()) |
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641 | |
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642 | DEFINE_STATIC(void,init,()) |
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643 | DEFINE_STATIC(void *,create,()) |
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644 | |
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645 | void ptytty_delete (void *ptytty) |
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646 | { |
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647 | delete (struct ptytty *)ptytty; |
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648 | } |
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649 | |
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650 | // send_fd, recv_fd not exposed |
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651 | |
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652 | #endif |