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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.17 by root, Mon Jan 23 11:22:52 2006 UTC vs.
Revision 1.31 by ayin, Thu Nov 15 10:49:05 2007 UTC

… …
29 29
30#include "ptytty.h" 30#include "ptytty.h"
31 31
32#include <cstdlib> 32#include <cstdlib>
33#include <cstring> 33#include <cstring>
34#include <csignal>
34 35
35#include <sys/types.h> 36#include <sys/types.h>
36#include <sys/socket.h>
37#include <unistd.h> 37#include <unistd.h>
38#include <fcntl.h> 38#include <fcntl.h>
39 39
40#ifdef HAVE_SYS_IOCTL_H 40#ifdef HAVE_SYS_IOCTL_H
41# include <sys/ioctl.h> 41# include <sys/ioctl.h>
… …
63 63
64/* ------------------------------------------------------------------------- * 64/* ------------------------------------------------------------------------- *
65 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 65 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
66 * ------------------------------------------------------------------------- */ 66 * ------------------------------------------------------------------------- */
67/* 67/*
68 * Returns pty file descriptor, or -1 on failure 68 * Returns pty file descriptor, or -1 on failure
69 * 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.
70 * 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
71 */ 71 */
72#if defined(UNIX98_PTY) 72#if defined(UNIX98_PTY)
73
73static int 74 static int
74get_pty (int *fd_tty, char **ttydev) 75 get_pty (int *fd_tty, char **ttydev)
75{ 76 {
76 int pfd; 77 int pfd;
77 78
78# if defined(HAVE_GETPT) 79# if defined(HAVE_GETPT)
79 pfd = getpt(); 80 pfd = getpt();
80# elif defined(HAVE_POSIX_OPENPT) 81# elif defined(HAVE_POSIX_OPENPT)
81 pfd = posix_openpt (O_RDWR); 82 pfd = posix_openpt (O_RDWR);
82# else 83# else
83 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 84 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0);
84# endif 85# endif
86
85 if (pfd >= 0) 87 if (pfd >= 0)
86 { 88 {
87 if (grantpt (pfd) == 0 /* change slave permissions */ 89 if (grantpt (pfd) == 0 /* change slave permissions */
88 && unlockpt (pfd) == 0) 90 && unlockpt (pfd) == 0)
89 { /* slave now unlocked */ 91 { /* slave now unlocked */
90 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 92 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
91 return pfd; 93 return pfd;
92 } 94 }
93 95
94 close (pfd); 96 close (pfd);
95 } 97 }
96 98
97 return -1; 99 return -1;
98} 100 }
101
99#elif defined(HAVE_OPENPTY) 102#elif defined(HAVE_OPENPTY)
103
100static int 104 static int
101get_pty (int *fd_tty, char **ttydev) 105 get_pty (int *fd_tty, char **ttydev)
102{ 106 {
103 int pfd; 107 int pfd;
104 int res; 108 int res;
105 char tty_name[32]; 109
106
107 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 110 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
111
108 if (res != -1) 112 if (res != -1)
109 { 113 {
114 *ttydev = strdup (ttyname (*fd_tty));
115 return pfd;
116 }
117
118 return -1;
119 }
120
121#elif defined(HAVE__GETPTY)
122
123 static int
124 get_pty (int *fd_tty, char **ttydev)
125 {
126 int pfd;
127 char *slave;
128
129 slave = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
130
131 if (slave != NULL) {
110 *ttydev = strdup (tty_name); 132 *ttydev = strdup (slave);
111 return pfd; 133 return pfd;
112 } 134 }
113 135
114 return -1; 136 return -1;
115} 137 }
116#elif defined(HAVE__GETPTY)
117static int
118get_pty (int *fd_tty, char **ttydev)
119{
120 int pfd;
121 138
122 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
123 if (*ttydev != NULL)
124 return pfd;
125
126 return -1;
127}
128#elif defined(HAVE_DEV_PTC) 139#elif defined(HAVE_DEV_PTC)
140
129static int 141 static int
130get_pty (int *fd_tty, char **ttydev) 142 get_pty (int *fd_tty, char **ttydev)
131{ 143 {
132 int pfd; 144 int pfd;
133 145
134 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 146 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
135 { 147 {
136 *ttydev = strdup (ttyname (pfd)); 148 *ttydev = strdup (ttyname (pfd));
137 return pfd; 149 return pfd;
138 } 150 }
139 151
140 return -1; 152 return -1;
141} 153 }
154
142#elif defined(HAVE_DEV_CLONE) 155#elif defined(HAVE_DEV_CLONE)
156
143static int 157 static int
144get_pty (int *fd_tty, char **ttydev) 158 get_pty (int *fd_tty, char **ttydev)
145{ 159 {
146 int pfd; 160 int pfd;
147 161
148 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0) 162 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
149 { 163 {
150 *ttydev = strdup (ptsname (pfd)); 164 *ttydev = strdup (ptsname (pfd));
151 return pfd; 165 return pfd;
152 } 166 }
153 167
154 return -1; 168 return -1;
155} 169 }
170
156#else 171#else
172
157/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 173 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
158static int 174 static int
159get_pty (int *fd_tty, char **ttydev) 175 get_pty (int *fd_tty, char **ttydev)
160{ 176 {
161 int pfd; 177 int pfd;
162 int i; 178 int i;
163 char pty_name[32]; 179 char pty_name[32];
164 char tty_name[32]; 180 char tty_name[32];
165 const char *majors = "pqrstuvwxyzabcde"; 181 const char *majors = "pqrstuvwxyzabcde";
166 const char *minors = "0123456789abcdef"; 182 const char *minors = "0123456789abcdef";
183
167 for (i = 0; i < 256; i++) 184 for (i = 0; i < 256; i++)
168 { 185 {
169 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 186 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]);
170 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]); 187 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
188
171 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 189 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
172 { 190 {
173 snprintf(pty_name, 32, "/dev/ptyp%d", i); 191 snprintf(pty_name, 32, "/dev/ptyp%d", i);
174 snprintf(tty_name, 32, "/dev/ttyp%d", i); 192 snprintf(tty_name, 32, "/dev/ttyp%d", i);
175 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 193 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
176 continue; 194 continue;
177 } 195 }
196
178 if (access (tty_name, R_OK | W_OK) == 0) 197 if (access (tty_name, R_OK | W_OK) == 0)
179 { 198 {
180 *ttydev = strdup (tty_name); 199 *ttydev = strdup (tty_name);
181 return pfd; 200 return pfd;
182 } 201 }
183 202
184 close (pfd); 203 close (pfd);
185 } 204 }
186} 205
206 return -1;
207 }
208
187#endif 209#endif
188 210
189/*----------------------------------------------------------------------*/ 211/*----------------------------------------------------------------------*/
190/* 212/*
191 * Returns tty file descriptor, or -1 on failure 213 * Returns tty file descriptor, or -1 on failure
192 */ 214 */
193static int 215static int
194get_tty (char *ttydev) 216get_tty (char *ttydev)
195{ 217{
196 return open (ttydev, O_RDWR | O_NOCTTY, 0); 218 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
201 * Make our tty a controlling tty so that /dev/tty points to us 223 * Make our tty a controlling tty so that /dev/tty points to us
202 */ 224 */
203static int 225static int
204control_tty (int fd_tty) 226control_tty (int fd_tty)
205{ 227{
228 int fd;
229
206 setsid (); 230 setsid ();
207 231
208#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 232#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
209 /* 233 /*
210 * Push STREAMS modules: 234 * Push STREAMS modules:
… …
231 ioctl (fd_tty, I_PUSH, "ldterm"); 255 ioctl (fd_tty, I_PUSH, "ldterm");
232 ioctl (fd_tty, I_PUSH, "ttcompat"); 256 ioctl (fd_tty, I_PUSH, "ttcompat");
233 } 257 }
234#endif 258#endif
235 259
260#ifdef TIOCSCTTY
236 ioctl (fd_tty, TIOCSCTTY, NULL); 261 ioctl (fd_tty, TIOCSCTTY, NULL);
262#else
263 fd = open (ttyname (fd_tty), O_RDWR);
264 if (fd >= 0)
265 close (fd);
266#endif
237 267
238 int fd = open ("/dev/tty", O_WRONLY); 268 fd = open ("/dev/tty", O_WRONLY);
239 if (fd < 0) 269 if (fd < 0)
240 return -1; /* fatal */ 270 return -1; /* fatal */
241 271
242 close (fd); 272 close (fd);
243 273
… …
300 { /* change group ownership of tty to "tty" */ 330 { /* change group ownership of tty to "tty" */
301 mode = S_IRUSR | S_IWUSR | S_IWGRP; 331 mode = S_IRUSR | S_IWUSR | S_IWGRP;
302 gid = gr->gr_gid; 332 gid = gr->gr_gid;
303 } 333 }
304 else 334 else
305#endif /* TTY_GID_SUPPORT */ 335#endif /* TTY_GID_SUPPORT */
306 { 336 {
307 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 337 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
308 gid = 0; 338 gid = 0;
309 } 339 }
310 } 340 }
… …
327} 357}
328 358
329void 359void
330ptytty_unix::put () 360ptytty_unix::put ()
331{ 361{
362 if (name)
363 {
332 chmod (name, RESTORE_TTY_MODE); 364 chmod (name, RESTORE_TTY_MODE);
333 chown (name, 0, ttyconf.gid); 365 chown (name, 0, ttyconf.gid);
366 }
334 367
335 close_tty (); 368 close_tty ();
336 369
337 if (pty >= 0) 370 if (pty >= 0)
338 close (pty); 371 close (pty);
… …
371 } 404 }
372 405
373 return true; 406 return true;
374} 407}
375 408
376/////////////////////////////////////////////////////////////////////////////
377// helper/proxy support
378
379#if PTYTTY_HELPER
380
381static int sock_fd = -1;
382static int helper_pid, owner_pid;
383
384struct command
385{
386 enum { get, login, destroy } type;
387
388 ptytty *id;
389
390 bool login_shell;
391 int cmd_pid;
392 char hostname[512]; // arbitrary, but should be plenty
393};
394
395struct ptytty_proxy : ptytty
396{
397 ptytty *id;
398
399 ptytty_proxy ()
400 : id(0)
401 {
402 }
403
404 ~ptytty_proxy ();
405
406 bool get ();
407 void login (int cmd_pid, bool login_shell, const char *hostname);
408};
409
410bool
411ptytty_proxy::get ()
412{
413 command cmd;
414
415 cmd.type = command::get;
416
417 write (sock_fd, &cmd, sizeof (cmd));
418
419 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
420 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
421
422 if (!id)
423 return false;
424
425 if ((pty = recv_fd (sock_fd)) < 0
426 || (tty = recv_fd (sock_fd)) < 0)
427 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
428
429 return true;
430}
431
432void
433ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
434{
435 command cmd;
436
437 cmd.type = command::login;
438 cmd.id = id;
439 cmd.cmd_pid = cmd_pid;
440 cmd.login_shell = login_shell;
441 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
442
443 write (sock_fd, &cmd, sizeof (cmd));
444}
445
446ptytty_proxy::~ptytty_proxy ()
447{
448 if (id)
449 {
450 command cmd;
451
452 cmd.type = command::destroy;
453 cmd.id = id;
454
455 write (sock_fd, &cmd, sizeof (cmd));
456 }
457}
458
459static
460void serve ()
461{
462 command cmd;
463 vector<ptytty *> ptys;
464
465 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
466 {
467 if (cmd.type == command::get)
468 {
469 // -> id ptyfd ttyfd
470 cmd.id = new ptytty_unix;
471
472 if (cmd.id->get ())
473 {
474 write (sock_fd, &cmd.id, sizeof (cmd.id));
475 ptys.push_back (cmd.id);
476
477 ptytty::send_fd (sock_fd, cmd.id->pty);
478 ptytty::send_fd (sock_fd, cmd.id->tty);
479 }
480 else
481 {
482 delete cmd.id;
483 cmd.id = 0;
484 write (sock_fd, &cmd.id, sizeof (cmd.id));
485 }
486 }
487 else if (cmd.type == command::login)
488 {
489#if UTMP_SUPPORT
490 if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ())
491 {
492 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
493 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
494 }
495#endif
496 }
497 else if (cmd.type == command::destroy)
498 {
499 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
500
501 if (pty != ptys.end ())
502 {
503 delete *pty;
504 ptys.erase (pty);
505 }
506 }
507 else
508 break;
509 }
510
511 // destroy all ptys
512 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
513 delete *i;
514}
515
516void
517ptytty::use_helper ()
518{
519 int pid = getpid ();
520
521 if (sock_fd >= 0 && pid == owner_pid)
522 return;
523
524 owner_pid = pid;
525
526 int sv[2];
527
528 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
529 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
530
531 helper_pid = fork ();
532
533 if (helper_pid < 0)
534 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
535
536 if (helper_pid)
537 {
538 // client, process
539 sock_fd = sv[0];
540 close (sv[1]);
541 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
542 }
543 else
544 {
545 // server, pty-helper
546 sock_fd = sv[1];
547
548 chdir ("/");
549
550 for (int fd = 0; fd < 1023; fd++)
551 if (fd != sock_fd)
552 close (fd);
553
554 serve ();
555 _exit (EXIT_SUCCESS);
556 }
557}
558
559#endif
560
561ptytty *
562ptytty::create ()
563{
564#if PTYTTY_HELPER
565 if (helper_pid && getpid () == owner_pid)
566 // use helper process
567 return new ptytty_proxy;
568 else
569#endif
570 return new ptytty_unix;
571}
572
573void
574ptytty::init ()
575{
576 uid_t uid = getuid ();
577 gid_t gid = getgid ();
578
579 // before doing anything else, check for setuid/setgid operation,
580 // start the helper process and drop privileges
581 if (uid != geteuid ()
582 || gid != getegid ())
583 {
584#if PTYTTY_HELPER
585 use_helper ();
586#else
587 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
588#endif
589
590 drop_privileges ();
591 }
592}
593
594void
595ptytty::drop_privileges ()
596{
597 uid_t uid = getuid ();
598 gid_t gid = getgid ();
599
600 // drop privileges
601#if HAVE_SETRESUID
602 setresgid (gid, gid, gid);
603 setresuid (uid, uid, uid);
604#elif HAVE_SETREUID
605 setregid (gid, gid);
606 setreuid (uid, uid);
607#elif HAVE_SETUID
608 setgid (gid);
609 setuid (uid);
610#endif
611
612 if (uid != geteuid ()
613 || gid != getegid ())
614 ptytty_fatal ("unable to drop privileges, aborting.\n");
615}
616
617/////////////////////////////////////////////////////////////////////////////
618// C API
619
620#ifndef NO_C_API
621
622#define DEFINE_METHOD(retval, name, args1, args2) \
623extern "C" retval ptytty_ ## name args1 \
624{ return ((struct ptytty *)ptytty)->name args2; }
625
626DEFINE_METHOD(int,pty,(void *ptytty),)
627DEFINE_METHOD(int,tty,(void *ptytty),)
628DEFINE_METHOD(int,get,(void *ptytty),())
629DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
630
631DEFINE_METHOD(void,close_tty,(void *ptytty),())
632DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),())
633DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on))
634
635#define DEFINE_STATIC(retval, name, args) \
636 retval ptytty_ ## name args \
637{ return ptytty::name args; }
638
639DEFINE_STATIC(void,drop_privileges,())
640DEFINE_STATIC(void,use_helper,())
641DEFINE_STATIC(void,init,())
642
643DEFINE_STATIC(void *,create,())
644
645void ptytty_delete (void *ptytty)
646{
647 delete (struct ptytty *)ptytty;
648}
649
650// send_fd, recv_fd not exposed
651
652#endif

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