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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.10 by root, Sun Jan 22 04:05:19 2006 UTC vs.
Revision 1.34 by ayin, Fri Dec 14 09:51:32 2007 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> 37#include <sys/stat.h>
36#include <unistd.h> 38#include <unistd.h>
37#include <fcntl.h> 39#include <fcntl.h>
38 40
39#ifdef HAVE_SYS_IOCTL_H 41#ifdef HAVE_SYS_IOCTL_H
40# include <sys/ioctl.h> 42# include <sys/ioctl.h>
… …
62 64
63/* ------------------------------------------------------------------------- * 65/* ------------------------------------------------------------------------- *
64 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 66 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
65 * ------------------------------------------------------------------------- */ 67 * ------------------------------------------------------------------------- */
66/* 68/*
67 * Returns pty file descriptor, or -1 on failure 69 * Returns pty file descriptor, or -1 on failure
68 * If successful, ttydev is set to the name of the slave device. 70 * If successful, ttydev is set to the name of the slave device.
69 * fd_tty _may_ also be set to an open fd to the slave device 71 * fd_tty _may_ also be set to an open fd to the slave device
70 */ 72 */
71#if defined(UNIX98_PTY) 73#if defined(UNIX98_PTY)
74
72static int 75 static int
73get_pty (int *fd_tty, char **ttydev) 76 get_pty (int *fd_tty, char **ttydev)
74{ 77 {
75 int pfd; 78 int pfd;
76 79
77# if defined(HAVE_GETPT) 80# if defined(HAVE_GETPT)
78 pfd = getpt(); 81 pfd = getpt();
79# elif defined(HAVE_POSIX_OPENPT) 82# elif defined(HAVE_POSIX_OPENPT)
80 pfd = posix_openpt (O_RDWR); 83 pfd = posix_openpt (O_RDWR);
81# else 84# else
82 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 85 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0);
83# endif 86# endif
87
84 if (pfd >= 0) 88 if (pfd >= 0)
85 { 89 {
86 if (grantpt (pfd) == 0 /* change slave permissions */ 90 if (grantpt (pfd) == 0 /* change slave permissions */
87 && unlockpt (pfd) == 0) 91 && unlockpt (pfd) == 0)
92 {
88 { /* slave now unlocked */ 93 /* slave now unlocked */
89 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 94 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
90 return pfd; 95 return pfd;
91 } 96 }
92 97
93 close (pfd); 98 close (pfd);
94 } 99 }
95 100
96 return -1; 101 return -1;
97} 102 }
103
98#elif defined(HAVE_OPENPTY) 104#elif defined(HAVE_OPENPTY)
105
99static int 106 static int
100get_pty (int *fd_tty, char **ttydev) 107 get_pty (int *fd_tty, char **ttydev)
101{ 108 {
102 int pfd; 109 int pfd;
103 int res; 110 int res;
104 char tty_name[32]; 111
105
106 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 112 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
113
107 if (res != -1) 114 if (res != -1)
108 { 115 {
109 *ttydev = strdup (tty_name); 116 *ttydev = strdup (ttyname (*fd_tty));
110 return pfd; 117 return pfd;
111 } 118 }
112 119
113 return -1; 120 return -1;
114} 121 }
122
115#elif defined(HAVE__GETPTY) 123#elif defined(HAVE__GETPTY)
124
116static int 125 static int
117get_pty (int *fd_tty, char **ttydev) 126 get_pty (int *fd_tty, char **ttydev)
118{ 127 {
119 int pfd; 128 int pfd;
129 char *slave;
120 130
121 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 131 slave = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
122 if (*ttydev != NULL) 132
133 if (slave != NULL)
134 {
135 *ttydev = strdup (slave);
123 return pfd; 136 return pfd;
137 }
124 138
125 return -1; 139 return -1;
126} 140 }
141
127#elif defined(HAVE_DEV_PTC) 142#elif defined(HAVE_DEV_PTC)
143
128static int 144 static int
129get_pty (int *fd_tty, char **ttydev) 145 get_pty (int *fd_tty, char **ttydev)
130{ 146 {
131 int pfd; 147 int pfd;
132 148
133 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 149 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
134 { 150 {
135 *ttydev = strdup (ttyname (pfd)); 151 *ttydev = strdup (ttyname (pfd));
136 return pfd; 152 return pfd;
137 } 153 }
138 154
139 return -1; 155 return -1;
140} 156 }
157
141#elif defined(HAVE_DEV_CLONE) 158#elif defined(HAVE_DEV_CLONE)
159
142static int 160 static int
143get_pty (int *fd_tty, char **ttydev) 161 get_pty (int *fd_tty, char **ttydev)
144{ 162 {
145 int pfd; 163 int pfd;
146 164
147 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0) 165 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
148 { 166 {
149 *ttydev = strdup (ptsname (pfd)); 167 *ttydev = strdup (ptsname (pfd));
150 return pfd; 168 return pfd;
151 } 169 }
152 170
153 return -1; 171 return -1;
154} 172 }
173
155#else 174#else
175
156/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 176 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
157static int 177 static int
158get_pty (int *fd_tty, char **ttydev) 178 get_pty (int *fd_tty, char **ttydev)
159{ 179 {
160 int pfd; 180 int pfd;
161 int i; 181 int i;
162 char pty_name[32]; 182 char pty_name[32];
163 char tty_name[32]; 183 char tty_name[32];
164 const char *majors = "pqrstuvwxyzabcde"; 184 const char *majors = "pqrstuvwxyzabcde";
165 const char *minors = "0123456789abcdef"; 185 const char *minors = "0123456789abcdef";
186
166 for (i = 0; i < 256; i++) 187 for (i = 0; i < 256; i++)
167 { 188 {
168 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 189 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]);
169 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]); 190 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
191
170 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 192 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
171 { 193 {
172 snprintf(pty_name, 32, "/dev/ptyp%d", i); 194 snprintf(pty_name, 32, "/dev/ptyp%d", i);
173 snprintf(tty_name, 32, "/dev/ttyp%d", i); 195 snprintf(tty_name, 32, "/dev/ttyp%d", i);
174 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 196 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
175 continue; 197 continue;
176 } 198 }
199
177 if (access (tty_name, R_OK | W_OK) == 0) 200 if (access (tty_name, R_OK | W_OK) == 0)
178 { 201 {
179 *ttydev = strdup (tty_name); 202 *ttydev = strdup (tty_name);
180 return pfd; 203 return pfd;
181 } 204 }
182 205
183 close (pfd); 206 close (pfd);
184 } 207 }
185} 208
209 return -1;
210 }
211
186#endif 212#endif
187 213
188/*----------------------------------------------------------------------*/ 214/*----------------------------------------------------------------------*/
189/* 215/*
190 * Returns tty file descriptor, or -1 on failure 216 * Returns tty file descriptor, or -1 on failure
191 */ 217 */
192static int 218static int
193get_tty (char *ttydev) 219get_tty (char *ttydev)
194{ 220{
195 return open (ttydev, O_RDWR | O_NOCTTY, 0); 221 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
200 * Make our tty a controlling tty so that /dev/tty points to us 226 * Make our tty a controlling tty so that /dev/tty points to us
201 */ 227 */
202static int 228static int
203control_tty (int fd_tty) 229control_tty (int fd_tty)
204{ 230{
231 int fd;
232
205 setsid (); 233 setsid ();
206 234
207#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 235#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
208 /* 236 /*
209 * Push STREAMS modules: 237 * Push STREAMS modules:
… …
230 ioctl (fd_tty, I_PUSH, "ldterm"); 258 ioctl (fd_tty, I_PUSH, "ldterm");
231 ioctl (fd_tty, I_PUSH, "ttcompat"); 259 ioctl (fd_tty, I_PUSH, "ttcompat");
232 } 260 }
233#endif 261#endif
234 262
263#ifdef TIOCSCTTY
235 ioctl (fd_tty, TIOCSCTTY, NULL); 264 ioctl (fd_tty, TIOCSCTTY, NULL);
265#else
266 fd = open (ttyname (fd_tty), O_RDWR);
267 if (fd >= 0)
268 close (fd);
269#endif
236 270
237 int fd = open ("/dev/tty", O_WRONLY); 271 fd = open ("/dev/tty", O_WRONLY);
238 if (fd < 0) 272 if (fd < 0)
239 return -1; /* fatal */ 273 return -1; /* fatal */
240 274
241 close (fd); 275 close (fd);
242 276
… …
294 { 328 {
295#ifdef TTY_GID_SUPPORT 329#ifdef TTY_GID_SUPPORT
296 struct group *gr = getgrnam ("tty"); 330 struct group *gr = getgrnam ("tty");
297 331
298 if (gr) 332 if (gr)
333 {
299 { /* change group ownership of tty to "tty" */ 334 /* change group ownership of tty to "tty" */
300 mode = S_IRUSR | S_IWUSR | S_IWGRP; 335 mode = S_IRUSR | S_IWUSR | S_IWGRP;
301 gid = gr->gr_gid; 336 gid = gr->gr_gid;
302 } 337 }
303 else 338 else
304#endif /* TTY_GID_SUPPORT */ 339#endif /* TTY_GID_SUPPORT */
305 { 340 {
306 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 341 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
307 gid = 0; 342 gid = 0;
308 } 343 }
309 } 344 }
… …
326} 361}
327 362
328void 363void
329ptytty_unix::put () 364ptytty_unix::put ()
330{ 365{
366 if (name)
367 {
331 chmod (name, RESTORE_TTY_MODE); 368 chmod (name, RESTORE_TTY_MODE);
332 chown (name, 0, ttyconf.gid); 369 chown (name, 0, ttyconf.gid);
370 }
333 371
334 close_tty (); 372 close_tty ();
335 373
336 if (pty >= 0) 374 if (pty >= 0)
337 close (pty); 375 close (pty);
… …
370 } 408 }
371 409
372 return true; 410 return true;
373} 411}
374 412
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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