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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.21 by root, Mon Jan 23 11:53:27 2006 UTC vs.
Revision 1.34 by ayin, Fri Dec 14 09:51:32 2007 UTC

… …
32#include <cstdlib> 32#include <cstdlib>
33#include <cstring> 33#include <cstring>
34#include <csignal> 34#include <csignal>
35 35
36#include <sys/types.h> 36#include <sys/types.h>
37#include <sys/socket.h> 37#include <sys/stat.h>
38#include <unistd.h> 38#include <unistd.h>
39#include <fcntl.h> 39#include <fcntl.h>
40 40
41#ifdef HAVE_SYS_IOCTL_H 41#ifdef HAVE_SYS_IOCTL_H
42# include <sys/ioctl.h> 42# include <sys/ioctl.h>
… …
64 64
65/* ------------------------------------------------------------------------- * 65/* ------------------------------------------------------------------------- *
66 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 66 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
67 * ------------------------------------------------------------------------- */ 67 * ------------------------------------------------------------------------- */
68/* 68/*
69 * Returns pty file descriptor, or -1 on failure 69 * Returns pty file descriptor, or -1 on failure
70 * 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.
71 * 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
72 */ 72 */
73#if defined(UNIX98_PTY) 73#if defined(UNIX98_PTY)
74
74static int 75 static int
75get_pty (int *fd_tty, char **ttydev) 76 get_pty (int *fd_tty, char **ttydev)
76{ 77 {
77 int pfd; 78 int pfd;
78 79
79# if defined(HAVE_GETPT) 80# if defined(HAVE_GETPT)
80 pfd = getpt(); 81 pfd = getpt();
81# elif defined(HAVE_POSIX_OPENPT) 82# elif defined(HAVE_POSIX_OPENPT)
82 pfd = posix_openpt (O_RDWR); 83 pfd = posix_openpt (O_RDWR);
83# else 84# else
84 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 85 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0);
85# endif 86# endif
87
86 if (pfd >= 0) 88 if (pfd >= 0)
87 { 89 {
88 if (grantpt (pfd) == 0 /* change slave permissions */ 90 if (grantpt (pfd) == 0 /* change slave permissions */
89 && unlockpt (pfd) == 0) 91 && unlockpt (pfd) == 0)
92 {
90 { /* slave now unlocked */ 93 /* slave now unlocked */
91 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 94 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
92 return pfd; 95 return pfd;
93 } 96 }
94 97
95 close (pfd); 98 close (pfd);
96 } 99 }
97 100
98 return -1; 101 return -1;
99} 102 }
103
100#elif defined(HAVE_OPENPTY) 104#elif defined(HAVE_OPENPTY)
105
101static int 106 static int
102get_pty (int *fd_tty, char **ttydev) 107 get_pty (int *fd_tty, char **ttydev)
103{ 108 {
104 int pfd; 109 int pfd;
105 int res; 110 int res;
106 char tty_name[32]; 111
107
108 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 112 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
113
109 if (res != -1) 114 if (res != -1)
110 { 115 {
111 *ttydev = strdup (tty_name); 116 *ttydev = strdup (ttyname (*fd_tty));
112 return pfd; 117 return pfd;
113 } 118 }
114 119
115 return -1; 120 return -1;
116} 121 }
122
117#elif defined(HAVE__GETPTY) 123#elif defined(HAVE__GETPTY)
124
118static int 125 static int
119get_pty (int *fd_tty, char **ttydev) 126 get_pty (int *fd_tty, char **ttydev)
120{ 127 {
121 int pfd; 128 int pfd;
129 char *slave;
122 130
123 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 131 slave = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
124 if (*ttydev != NULL) 132
133 if (slave != NULL)
134 {
135 *ttydev = strdup (slave);
125 return pfd; 136 return pfd;
137 }
126 138
127 return -1; 139 return -1;
128} 140 }
141
129#elif defined(HAVE_DEV_PTC) 142#elif defined(HAVE_DEV_PTC)
143
130static int 144 static int
131get_pty (int *fd_tty, char **ttydev) 145 get_pty (int *fd_tty, char **ttydev)
132{ 146 {
133 int pfd; 147 int pfd;
134 148
135 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 149 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
136 { 150 {
137 *ttydev = strdup (ttyname (pfd)); 151 *ttydev = strdup (ttyname (pfd));
138 return pfd; 152 return pfd;
139 } 153 }
140 154
141 return -1; 155 return -1;
142} 156 }
157
143#elif defined(HAVE_DEV_CLONE) 158#elif defined(HAVE_DEV_CLONE)
159
144static int 160 static int
145get_pty (int *fd_tty, char **ttydev) 161 get_pty (int *fd_tty, char **ttydev)
146{ 162 {
147 int pfd; 163 int pfd;
148 164
149 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)
150 { 166 {
151 *ttydev = strdup (ptsname (pfd)); 167 *ttydev = strdup (ptsname (pfd));
152 return pfd; 168 return pfd;
153 } 169 }
154 170
155 return -1; 171 return -1;
156} 172 }
173
157#else 174#else
175
158/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 176 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
159static int 177 static int
160get_pty (int *fd_tty, char **ttydev) 178 get_pty (int *fd_tty, char **ttydev)
161{ 179 {
162 int pfd; 180 int pfd;
163 int i; 181 int i;
164 char pty_name[32]; 182 char pty_name[32];
165 char tty_name[32]; 183 char tty_name[32];
166 const char *majors = "pqrstuvwxyzabcde"; 184 const char *majors = "pqrstuvwxyzabcde";
167 const char *minors = "0123456789abcdef"; 185 const char *minors = "0123456789abcdef";
186
168 for (i = 0; i < 256; i++) 187 for (i = 0; i < 256; i++)
169 { 188 {
170 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]);
171 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
172 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 192 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
173 { 193 {
174 snprintf(pty_name, 32, "/dev/ptyp%d", i); 194 snprintf(pty_name, 32, "/dev/ptyp%d", i);
175 snprintf(tty_name, 32, "/dev/ttyp%d", i); 195 snprintf(tty_name, 32, "/dev/ttyp%d", i);
176 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 196 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
177 continue; 197 continue;
178 } 198 }
199
179 if (access (tty_name, R_OK | W_OK) == 0) 200 if (access (tty_name, R_OK | W_OK) == 0)
180 { 201 {
181 *ttydev = strdup (tty_name); 202 *ttydev = strdup (tty_name);
182 return pfd; 203 return pfd;
183 } 204 }
184 205
185 close (pfd); 206 close (pfd);
186 } 207 }
187} 208
209 return -1;
210 }
211
188#endif 212#endif
189 213
190/*----------------------------------------------------------------------*/ 214/*----------------------------------------------------------------------*/
191/* 215/*
192 * Returns tty file descriptor, or -1 on failure 216 * Returns tty file descriptor, or -1 on failure
193 */ 217 */
194static int 218static int
195get_tty (char *ttydev) 219get_tty (char *ttydev)
196{ 220{
197 return open (ttydev, O_RDWR | O_NOCTTY, 0); 221 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
202 * 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
203 */ 227 */
204static int 228static int
205control_tty (int fd_tty) 229control_tty (int fd_tty)
206{ 230{
231 int fd;
232
207 setsid (); 233 setsid ();
208 234
209#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 235#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
210 /* 236 /*
211 * Push STREAMS modules: 237 * Push STREAMS modules:
… …
232 ioctl (fd_tty, I_PUSH, "ldterm"); 258 ioctl (fd_tty, I_PUSH, "ldterm");
233 ioctl (fd_tty, I_PUSH, "ttcompat"); 259 ioctl (fd_tty, I_PUSH, "ttcompat");
234 } 260 }
235#endif 261#endif
236 262
263#ifdef TIOCSCTTY
237 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
238 270
239 int fd = open ("/dev/tty", O_WRONLY); 271 fd = open ("/dev/tty", O_WRONLY);
240 if (fd < 0) 272 if (fd < 0)
241 return -1; /* fatal */ 273 return -1; /* fatal */
242 274
243 close (fd); 275 close (fd);
244 276
… …
296 { 328 {
297#ifdef TTY_GID_SUPPORT 329#ifdef TTY_GID_SUPPORT
298 struct group *gr = getgrnam ("tty"); 330 struct group *gr = getgrnam ("tty");
299 331
300 if (gr) 332 if (gr)
333 {
301 { /* change group ownership of tty to "tty" */ 334 /* change group ownership of tty to "tty" */
302 mode = S_IRUSR | S_IWUSR | S_IWGRP; 335 mode = S_IRUSR | S_IWUSR | S_IWGRP;
303 gid = gr->gr_gid; 336 gid = gr->gr_gid;
304 } 337 }
305 else 338 else
306#endif /* TTY_GID_SUPPORT */ 339#endif /* TTY_GID_SUPPORT */
307 { 340 {
308 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 341 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
309 gid = 0; 342 gid = 0;
310 } 343 }
311 } 344 }
… …
328} 361}
329 362
330void 363void
331ptytty_unix::put () 364ptytty_unix::put ()
332{ 365{
366 if (name)
367 {
333 chmod (name, RESTORE_TTY_MODE); 368 chmod (name, RESTORE_TTY_MODE);
334 chown (name, 0, ttyconf.gid); 369 chown (name, 0, ttyconf.gid);
370 }
335 371
336 close_tty (); 372 close_tty ();
337 373
338 if (pty >= 0) 374 if (pty >= 0)
339 close (pty); 375 close (pty);
… …
372 } 408 }
373 409
374 return true; 410 return true;
375} 411}
376 412
377/////////////////////////////////////////////////////////////////////////////
378// helper/proxy support
379
380#if PTYTTY_HELPER
381
382static int sock_fd = -1, lock_fd = -1;
383static int helper_pid, owner_pid;
384
385struct command
386{
387 enum { get, login, destroy } type;
388
389 ptytty *id;
390
391 bool login_shell;
392 int cmd_pid;
393 char hostname[512]; // arbitrary, but should be plenty
394};
395
396struct ptytty_proxy : ptytty
397{
398 ptytty *id;
399
400 ptytty_proxy ()
401 : id(0)
402 {
403 }
404
405 ~ptytty_proxy ();
406
407 bool get ();
408 void login (int cmd_pid, bool login_shell, const char *hostname);
409};
410
411#if PTYTTY_REENTRANT
412# define NEED_TOKEN do { char ch; read (lock_fd, &ch, 1); } while (0)
413# define GIVE_TOKEN do { char ch; write (lock_fd, &ch, 1); } while (0)
414#else
415# define NEED_TOKEN (void)0
416# define GIVE_TOKEN (void)0
417#endif
418
419bool
420ptytty_proxy::get ()
421{
422 NEED_TOKEN;
423
424 command cmd;
425
426 cmd.type = command::get;
427
428 write (sock_fd, &cmd, sizeof (cmd));
429
430 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
431 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
432
433 if (!id)
434 {
435 GIVE_TOKEN;
436 return false;
437 }
438
439 if ((pty = recv_fd (sock_fd)) < 0
440 || (tty = recv_fd (sock_fd)) < 0)
441 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
442
443 GIVE_TOKEN;
444 return true;
445}
446
447void
448ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
449{
450 NEED_TOKEN;
451
452 command cmd;
453
454 cmd.type = command::login;
455 cmd.id = id;
456 cmd.cmd_pid = cmd_pid;
457 cmd.login_shell = login_shell;
458 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
459
460 write (sock_fd, &cmd, sizeof (cmd));
461
462 GIVE_TOKEN;
463}
464
465ptytty_proxy::~ptytty_proxy ()
466{
467 if (id)
468 {
469 NEED_TOKEN;
470
471 command cmd;
472
473 cmd.type = command::destroy;
474 cmd.id = id;
475
476 write (sock_fd, &cmd, sizeof (cmd));
477
478 GIVE_TOKEN;
479 }
480}
481
482static
483void serve ()
484{
485 command cmd;
486 vector<ptytty *> ptys;
487
488 for (;;)
489 {
490 GIVE_TOKEN;
491
492 if (read (sock_fd, &cmd, sizeof (command)) != sizeof (command))
493 break;
494
495 if (cmd.type == command::get)
496 {
497 // -> id ptyfd ttyfd
498 cmd.id = new ptytty_unix;
499
500 if (cmd.id->get ())
501 {
502 write (sock_fd, &cmd.id, sizeof (cmd.id));
503 ptys.push_back (cmd.id);
504
505 ptytty::send_fd (sock_fd, cmd.id->pty);
506 ptytty::send_fd (sock_fd, cmd.id->tty);
507 }
508 else
509 {
510 delete cmd.id;
511 cmd.id = 0;
512 write (sock_fd, &cmd.id, sizeof (cmd.id));
513 }
514 }
515 else if (cmd.type == command::login)
516 {
517#if UTMP_SUPPORT
518 if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ())
519 {
520 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
521 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
522 }
523#endif
524 }
525 else if (cmd.type == command::destroy)
526 {
527 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
528
529 if (pty != ptys.end ())
530 {
531 delete *pty;
532 ptys.erase (pty);
533 }
534 }
535 else
536 break;
537
538 NEED_TOKEN;
539 }
540
541 // destroy all ptys
542 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
543 delete *i;
544}
545
546void
547ptytty::use_helper ()
548{
549#ifndef PTYTTY_NO_PID_CHECK
550 int pid = getpid ();
551#endif
552
553 if (sock_fd >= 0
554#ifndef PTYTTY_NO_PID_CHECK
555 && pid == owner_pid
556#endif
557 )
558 return;
559
560#ifndef PTYTTY_NO_PID_CHECK
561 owner_pid = pid;
562#endif
563
564 int sv[2];
565
566 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
567 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
568
569#ifdef PTYTTY_REENTRANT
570 int lv[2];
571
572 if (socketpair (AF_UNIX, SOCK_STREAM, 0, lv))
573 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
574#endif
575
576 helper_pid = fork ();
577
578 if (helper_pid < 0)
579 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
580
581 if (helper_pid)
582 {
583 // client, process
584 sock_fd = sv[0];
585 close (sv[1]);
586 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
587#ifdef PTYTTY_REENTRANT
588 lock_fd = lv[0];
589 close (lv[1]);
590 fcntl (lock_fd, F_SETFD, FD_CLOEXEC);
591#endif
592 }
593 else
594 {
595 // server, pty-helper
596 sock_fd = sv[1];
597#ifdef PTYTTY_REENTRANT
598 lock_fd = lv[1];
599#endif
600
601 chdir ("/");
602
603 signal (SIGHUP, SIG_IGN);
604 signal (SIGTERM, SIG_IGN);
605 signal (SIGINT, SIG_IGN);
606 signal (SIGPIPE, SIG_IGN);
607
608 for (int fd = 0; fd < 1023; fd++)
609 if (fd != sock_fd && fd != lock_fd)
610 close (fd);
611
612 serve ();
613 _exit (EXIT_SUCCESS);
614 }
615}
616
617#endif
618
619ptytty *
620ptytty::create ()
621{
622#if PTYTTY_HELPER
623 if (helper_pid
624# ifndef PTYTTY_NO_PID_CHECK
625 && getpid () == owner_pid
626# endif
627 )
628 // use helper process
629 return new ptytty_proxy;
630 else
631#endif
632 return new ptytty_unix;
633}
634
635void
636ptytty::init ()
637{
638 uid_t uid = getuid ();
639 gid_t gid = getgid ();
640
641 // before doing anything else, check for setuid/setgid operation,
642 // start the helper process and drop privileges
643 if (uid != geteuid ()
644 || gid != getegid ())
645 {
646#if PTYTTY_HELPER
647 use_helper ();
648#else
649 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
650#endif
651
652 drop_privileges ();
653 }
654}
655
656void
657ptytty::drop_privileges ()
658{
659 uid_t uid = getuid ();
660 gid_t gid = getgid ();
661
662 // drop privileges
663#if HAVE_SETRESUID
664 setresgid (gid, gid, gid);
665 setresuid (uid, uid, uid);
666#elif HAVE_SETREUID
667 setregid (gid, gid);
668 setreuid (uid, uid);
669#elif HAVE_SETUID
670 setgid (gid);
671 setuid (uid);
672#endif
673
674 if (uid != geteuid ()
675 || gid != getegid ())
676 ptytty_fatal ("unable to drop privileges, aborting.\n");
677}
678
679/////////////////////////////////////////////////////////////////////////////
680// C API
681
682#ifndef PTYTTY_NO_C_API
683
684#define DEFINE_METHOD(retval, name, args1, args2) \
685extern "C" retval ptytty_ ## name args1 \
686{ return ((struct ptytty *)ptytty)->name args2; }
687
688DEFINE_METHOD(int,pty,(void *ptytty),)
689DEFINE_METHOD(int,tty,(void *ptytty),)
690DEFINE_METHOD(int,get,(void *ptytty),())
691DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
692
693DEFINE_METHOD(void,close_tty,(void *ptytty),())
694DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),())
695DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on))
696
697#define DEFINE_STATIC(retval, name, args) \
698extern "C" retval ptytty_ ## name args \
699{ return ptytty::name args; }
700
701DEFINE_STATIC(void,drop_privileges,())
702DEFINE_STATIC(void,use_helper,())
703DEFINE_STATIC(void,init,())
704
705DEFINE_STATIC(void *,create,())
706
707void ptytty_delete (void *ptytty)
708{
709 delete (struct ptytty *)ptytty;
710}
711
712// send_fd, recv_fd not exposed
713
714#endif

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