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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.19 by root, Mon Jan 23 11:36:01 2006 UTC vs.
Revision 1.33 by ayin, Thu Dec 13 14:42:33 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>
38#include <unistd.h> 37#include <unistd.h>
39#include <fcntl.h> 38#include <fcntl.h>
40 39
41#ifdef HAVE_SYS_IOCTL_H 40#ifdef HAVE_SYS_IOCTL_H
42# include <sys/ioctl.h> 41# include <sys/ioctl.h>
… …
64 63
65/* ------------------------------------------------------------------------- * 64/* ------------------------------------------------------------------------- *
66 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 65 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
67 * ------------------------------------------------------------------------- */ 66 * ------------------------------------------------------------------------- */
68/* 67/*
69 * Returns pty file descriptor, or -1 on failure 68 * Returns pty file descriptor, or -1 on failure
70 * If successful, ttydev is set to the name of the slave device. 69 * 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 70 * fd_tty _may_ also be set to an open fd to the slave device
72 */ 71 */
73#if defined(UNIX98_PTY) 72#if defined(UNIX98_PTY)
73
74static int 74 static int
75get_pty (int *fd_tty, char **ttydev) 75 get_pty (int *fd_tty, char **ttydev)
76{ 76 {
77 int pfd; 77 int pfd;
78 78
79# if defined(HAVE_GETPT) 79# if defined(HAVE_GETPT)
80 pfd = getpt(); 80 pfd = getpt();
81# elif defined(HAVE_POSIX_OPENPT) 81# elif defined(HAVE_POSIX_OPENPT)
82 pfd = posix_openpt (O_RDWR); 82 pfd = posix_openpt (O_RDWR);
83# else 83# else
84 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 84 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0);
85# endif 85# endif
86
86 if (pfd >= 0) 87 if (pfd >= 0)
87 { 88 {
88 if (grantpt (pfd) == 0 /* change slave permissions */ 89 if (grantpt (pfd) == 0 /* change slave permissions */
89 && unlockpt (pfd) == 0) 90 && unlockpt (pfd) == 0)
91 {
90 { /* slave now unlocked */ 92 /* slave now unlocked */
91 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 93 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
92 return pfd; 94 return pfd;
93 } 95 }
94 96
95 close (pfd); 97 close (pfd);
96 } 98 }
97 99
98 return -1; 100 return -1;
99} 101 }
102
100#elif defined(HAVE_OPENPTY) 103#elif defined(HAVE_OPENPTY)
104
101static int 105 static int
102get_pty (int *fd_tty, char **ttydev) 106 get_pty (int *fd_tty, char **ttydev)
103{ 107 {
104 int pfd; 108 int pfd;
105 int res; 109 int res;
106 char tty_name[32]; 110
107
108 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 111 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
112
109 if (res != -1) 113 if (res != -1)
110 { 114 {
111 *ttydev = strdup (tty_name); 115 *ttydev = strdup (ttyname (*fd_tty));
112 return pfd; 116 return pfd;
113 } 117 }
114 118
115 return -1; 119 return -1;
116} 120 }
121
117#elif defined(HAVE__GETPTY) 122#elif defined(HAVE__GETPTY)
123
118static int 124 static int
119get_pty (int *fd_tty, char **ttydev) 125 get_pty (int *fd_tty, char **ttydev)
120{ 126 {
121 int pfd; 127 int pfd;
128 char *slave;
122 129
123 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 130 slave = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
124 if (*ttydev != NULL) 131
132 if (slave != NULL)
133 {
134 *ttydev = strdup (slave);
125 return pfd; 135 return pfd;
136 }
126 137
127 return -1; 138 return -1;
128} 139 }
140
129#elif defined(HAVE_DEV_PTC) 141#elif defined(HAVE_DEV_PTC)
142
130static int 143 static int
131get_pty (int *fd_tty, char **ttydev) 144 get_pty (int *fd_tty, char **ttydev)
132{ 145 {
133 int pfd; 146 int pfd;
134 147
135 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 148 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
136 { 149 {
137 *ttydev = strdup (ttyname (pfd)); 150 *ttydev = strdup (ttyname (pfd));
138 return pfd; 151 return pfd;
139 } 152 }
140 153
141 return -1; 154 return -1;
142} 155 }
156
143#elif defined(HAVE_DEV_CLONE) 157#elif defined(HAVE_DEV_CLONE)
158
144static int 159 static int
145get_pty (int *fd_tty, char **ttydev) 160 get_pty (int *fd_tty, char **ttydev)
146{ 161 {
147 int pfd; 162 int pfd;
148 163
149 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0) 164 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
150 { 165 {
151 *ttydev = strdup (ptsname (pfd)); 166 *ttydev = strdup (ptsname (pfd));
152 return pfd; 167 return pfd;
153 } 168 }
154 169
155 return -1; 170 return -1;
156} 171 }
172
157#else 173#else
174
158/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 175 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
159static int 176 static int
160get_pty (int *fd_tty, char **ttydev) 177 get_pty (int *fd_tty, char **ttydev)
161{ 178 {
162 int pfd; 179 int pfd;
163 int i; 180 int i;
164 char pty_name[32]; 181 char pty_name[32];
165 char tty_name[32]; 182 char tty_name[32];
166 const char *majors = "pqrstuvwxyzabcde"; 183 const char *majors = "pqrstuvwxyzabcde";
167 const char *minors = "0123456789abcdef"; 184 const char *minors = "0123456789abcdef";
185
168 for (i = 0; i < 256; i++) 186 for (i = 0; i < 256; i++)
169 { 187 {
170 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 188 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]); 189 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
190
172 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 191 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
173 { 192 {
174 snprintf(pty_name, 32, "/dev/ptyp%d", i); 193 snprintf(pty_name, 32, "/dev/ptyp%d", i);
175 snprintf(tty_name, 32, "/dev/ttyp%d", i); 194 snprintf(tty_name, 32, "/dev/ttyp%d", i);
176 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 195 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
177 continue; 196 continue;
178 } 197 }
198
179 if (access (tty_name, R_OK | W_OK) == 0) 199 if (access (tty_name, R_OK | W_OK) == 0)
180 { 200 {
181 *ttydev = strdup (tty_name); 201 *ttydev = strdup (tty_name);
182 return pfd; 202 return pfd;
183 } 203 }
184 204
185 close (pfd); 205 close (pfd);
186 } 206 }
187} 207
208 return -1;
209 }
210
188#endif 211#endif
189 212
190/*----------------------------------------------------------------------*/ 213/*----------------------------------------------------------------------*/
191/* 214/*
192 * Returns tty file descriptor, or -1 on failure 215 * Returns tty file descriptor, or -1 on failure
193 */ 216 */
194static int 217static int
195get_tty (char *ttydev) 218get_tty (char *ttydev)
196{ 219{
197 return open (ttydev, O_RDWR | O_NOCTTY, 0); 220 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
202 * Make our tty a controlling tty so that /dev/tty points to us 225 * Make our tty a controlling tty so that /dev/tty points to us
203 */ 226 */
204static int 227static int
205control_tty (int fd_tty) 228control_tty (int fd_tty)
206{ 229{
230 int fd;
231
207 setsid (); 232 setsid ();
208 233
209#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 234#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
210 /* 235 /*
211 * Push STREAMS modules: 236 * Push STREAMS modules:
… …
232 ioctl (fd_tty, I_PUSH, "ldterm"); 257 ioctl (fd_tty, I_PUSH, "ldterm");
233 ioctl (fd_tty, I_PUSH, "ttcompat"); 258 ioctl (fd_tty, I_PUSH, "ttcompat");
234 } 259 }
235#endif 260#endif
236 261
262#ifdef TIOCSCTTY
237 ioctl (fd_tty, TIOCSCTTY, NULL); 263 ioctl (fd_tty, TIOCSCTTY, NULL);
264#else
265 fd = open (ttyname (fd_tty), O_RDWR);
266 if (fd >= 0)
267 close (fd);
268#endif
238 269
239 int fd = open ("/dev/tty", O_WRONLY); 270 fd = open ("/dev/tty", O_WRONLY);
240 if (fd < 0) 271 if (fd < 0)
241 return -1; /* fatal */ 272 return -1; /* fatal */
242 273
243 close (fd); 274 close (fd);
244 275
… …
296 { 327 {
297#ifdef TTY_GID_SUPPORT 328#ifdef TTY_GID_SUPPORT
298 struct group *gr = getgrnam ("tty"); 329 struct group *gr = getgrnam ("tty");
299 330
300 if (gr) 331 if (gr)
332 {
301 { /* change group ownership of tty to "tty" */ 333 /* change group ownership of tty to "tty" */
302 mode = S_IRUSR | S_IWUSR | S_IWGRP; 334 mode = S_IRUSR | S_IWUSR | S_IWGRP;
303 gid = gr->gr_gid; 335 gid = gr->gr_gid;
304 } 336 }
305 else 337 else
306#endif /* TTY_GID_SUPPORT */ 338#endif /* TTY_GID_SUPPORT */
307 { 339 {
308 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 340 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
309 gid = 0; 341 gid = 0;
310 } 342 }
311 } 343 }
… …
328} 360}
329 361
330void 362void
331ptytty_unix::put () 363ptytty_unix::put ()
332{ 364{
365 if (name)
366 {
333 chmod (name, RESTORE_TTY_MODE); 367 chmod (name, RESTORE_TTY_MODE);
334 chown (name, 0, ttyconf.gid); 368 chown (name, 0, ttyconf.gid);
369 }
335 370
336 close_tty (); 371 close_tty ();
337 372
338 if (pty >= 0) 373 if (pty >= 0)
339 close (pty); 374 close (pty);
… …
372 } 407 }
373 408
374 return true; 409 return true;
375} 410}
376 411
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
411bool
412ptytty_proxy::get ()
413{
414 command cmd;
415
416 cmd.type = command::get;
417
418 write (sock_fd, &cmd, sizeof (cmd));
419
420 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
421 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
422
423 if (!id)
424 return false;
425
426 if ((pty = recv_fd (sock_fd)) < 0
427 || (tty = recv_fd (sock_fd)) < 0)
428 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
429
430 return true;
431}
432
433void
434ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
435{
436 command cmd;
437
438 cmd.type = command::login;
439 cmd.id = id;
440 cmd.cmd_pid = cmd_pid;
441 cmd.login_shell = login_shell;
442 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
443
444 write (sock_fd, &cmd, sizeof (cmd));
445}
446
447ptytty_proxy::~ptytty_proxy ()
448{
449 if (id)
450 {
451 command cmd;
452
453 cmd.type = command::destroy;
454 cmd.id = id;
455
456 write (sock_fd, &cmd, sizeof (cmd));
457 }
458}
459
460static
461void serve ()
462{
463 command cmd;
464 vector<ptytty *> ptys;
465
466 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
467 {
468 if (cmd.type == command::get)
469 {
470 // -> id ptyfd ttyfd
471 cmd.id = new ptytty_unix;
472
473 if (cmd.id->get ())
474 {
475 write (sock_fd, &cmd.id, sizeof (cmd.id));
476 ptys.push_back (cmd.id);
477
478 ptytty::send_fd (sock_fd, cmd.id->pty);
479 ptytty::send_fd (sock_fd, cmd.id->tty);
480 }
481 else
482 {
483 delete cmd.id;
484 cmd.id = 0;
485 write (sock_fd, &cmd.id, sizeof (cmd.id));
486 }
487 }
488 else if (cmd.type == command::login)
489 {
490#if UTMP_SUPPORT
491 if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ())
492 {
493 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
494 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
495 }
496#endif
497 }
498 else if (cmd.type == command::destroy)
499 {
500 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
501
502 if (pty != ptys.end ())
503 {
504 delete *pty;
505 ptys.erase (pty);
506 }
507 }
508 else
509 break;
510 }
511
512 // destroy all ptys
513 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
514 delete *i;
515}
516
517void
518ptytty::use_helper ()
519{
520 int pid = getpid ();
521
522 if (sock_fd >= 0 && pid == owner_pid)
523 return;
524
525 owner_pid = pid;
526
527 int sv[2];
528
529 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
530 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
531
532#ifdef PTYTTY_REENTRANT
533 int lv[2];
534
535 if (socketpair (AF_UNIX, SOCK_STREAM, 0, lv))
536 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
537#endif
538
539 helper_pid = fork ();
540
541 if (helper_pid < 0)
542 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
543
544 if (helper_pid)
545 {
546 // client, process
547 sock_fd = sv[0];
548 close (sv[1]);
549 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
550#ifdef PTYTTY_REENTRANT
551 lock_fd = lv[0];
552 close (lv[1]);
553 fcntl (lock_fd, F_SETFD, FD_CLOEXEC);
554#endif
555 }
556 else
557 {
558 // server, pty-helper
559 sock_fd = sv[1];
560#ifdef PTYTTY_REENTRANT
561 lock_fd = lv[1];
562#endif
563
564 chdir ("/");
565
566 signal (SIGHUP, SIG_IGN);
567 signal (SIGTERM, SIG_IGN);
568 signal (SIGINT, SIG_IGN);
569 signal (SIGPIPE, SIG_IGN);
570
571 for (int fd = 0; fd < 1023; fd++)
572 if (fd != sock_fd && fd != lock_fd)
573 close (fd);
574
575 serve ();
576 _exit (EXIT_SUCCESS);
577 }
578}
579
580#endif
581
582ptytty *
583ptytty::create ()
584{
585#if PTYTTY_HELPER
586 if (helper_pid && getpid () == owner_pid)
587 // use helper process
588 return new ptytty_proxy;
589 else
590#endif
591 return new ptytty_unix;
592}
593
594void
595ptytty::init ()
596{
597 uid_t uid = getuid ();
598 gid_t gid = getgid ();
599
600 // before doing anything else, check for setuid/setgid operation,
601 // start the helper process and drop privileges
602 if (uid != geteuid ()
603 || gid != getegid ())
604 {
605#if PTYTTY_HELPER
606 use_helper ();
607#else
608 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
609#endif
610
611 drop_privileges ();
612 }
613}
614
615void
616ptytty::drop_privileges ()
617{
618 uid_t uid = getuid ();
619 gid_t gid = getgid ();
620
621 // drop privileges
622#if HAVE_SETRESUID
623 setresgid (gid, gid, gid);
624 setresuid (uid, uid, uid);
625#elif HAVE_SETREUID
626 setregid (gid, gid);
627 setreuid (uid, uid);
628#elif HAVE_SETUID
629 setgid (gid);
630 setuid (uid);
631#endif
632
633 if (uid != geteuid ()
634 || gid != getegid ())
635 ptytty_fatal ("unable to drop privileges, aborting.\n");
636}
637
638/////////////////////////////////////////////////////////////////////////////
639// C API
640
641#ifndef NO_C_API
642
643#define DEFINE_METHOD(retval, name, args1, args2) \
644extern "C" retval ptytty_ ## name args1 \
645{ return ((struct ptytty *)ptytty)->name args2; }
646
647DEFINE_METHOD(int,pty,(void *ptytty),)
648DEFINE_METHOD(int,tty,(void *ptytty),)
649DEFINE_METHOD(int,get,(void *ptytty),())
650DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
651
652DEFINE_METHOD(void,close_tty,(void *ptytty),())
653DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),())
654DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on))
655
656#define DEFINE_STATIC(retval, name, args) \
657extern "C" retval ptytty_ ## name args \
658{ return ptytty::name args; }
659
660DEFINE_STATIC(void,drop_privileges,())
661DEFINE_STATIC(void,use_helper,())
662DEFINE_STATIC(void,init,())
663
664DEFINE_STATIC(void *,create,())
665
666void ptytty_delete (void *ptytty)
667{
668 delete (struct ptytty *)ptytty;
669}
670
671// send_fd, recv_fd not exposed
672
673#endif

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