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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.12 by root, Sun Jan 22 12:22:37 2006 UTC vs.
Revision 1.34 by ayin, Fri Dec 14 09:51:32 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 <sys/stat.h>
37#include <unistd.h> 38#include <unistd.h>
38#include <fcntl.h> 39#include <fcntl.h>
39 40
40#ifdef HAVE_SYS_IOCTL_H 41#ifdef HAVE_SYS_IOCTL_H
41# include <sys/ioctl.h> 42# include <sys/ioctl.h>
… …
63 64
64/* ------------------------------------------------------------------------- * 65/* ------------------------------------------------------------------------- *
65 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 66 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
66 * ------------------------------------------------------------------------- */ 67 * ------------------------------------------------------------------------- */
67/* 68/*
68 * Returns pty file descriptor, or -1 on failure 69 * Returns pty file descriptor, or -1 on failure
69 * 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.
70 * 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
71 */ 72 */
72#if defined(UNIX98_PTY) 73#if defined(UNIX98_PTY)
74
73static int 75 static int
74get_pty (int *fd_tty, char **ttydev) 76 get_pty (int *fd_tty, char **ttydev)
75{ 77 {
76 int pfd; 78 int pfd;
77 79
78# if defined(HAVE_GETPT) 80# if defined(HAVE_GETPT)
79 pfd = getpt(); 81 pfd = getpt();
80# elif defined(HAVE_POSIX_OPENPT) 82# elif defined(HAVE_POSIX_OPENPT)
81 pfd = posix_openpt (O_RDWR); 83 pfd = posix_openpt (O_RDWR);
82# else 84# else
83 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 85 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0);
84# endif 86# endif
87
85 if (pfd >= 0) 88 if (pfd >= 0)
86 { 89 {
87 if (grantpt (pfd) == 0 /* change slave permissions */ 90 if (grantpt (pfd) == 0 /* change slave permissions */
88 && unlockpt (pfd) == 0) 91 && unlockpt (pfd) == 0)
92 {
89 { /* slave now unlocked */ 93 /* slave now unlocked */
90 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 94 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
91 return pfd; 95 return pfd;
92 } 96 }
93 97
94 close (pfd); 98 close (pfd);
95 } 99 }
96 100
97 return -1; 101 return -1;
98} 102 }
103
99#elif defined(HAVE_OPENPTY) 104#elif defined(HAVE_OPENPTY)
105
100static int 106 static int
101get_pty (int *fd_tty, char **ttydev) 107 get_pty (int *fd_tty, char **ttydev)
102{ 108 {
103 int pfd; 109 int pfd;
104 int res; 110 int res;
105 char tty_name[32]; 111
106
107 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 112 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
113
108 if (res != -1) 114 if (res != -1)
109 { 115 {
110 *ttydev = strdup (tty_name); 116 *ttydev = strdup (ttyname (*fd_tty));
111 return pfd; 117 return pfd;
112 } 118 }
113 119
114 return -1; 120 return -1;
115} 121 }
122
116#elif defined(HAVE__GETPTY) 123#elif defined(HAVE__GETPTY)
124
117static int 125 static int
118get_pty (int *fd_tty, char **ttydev) 126 get_pty (int *fd_tty, char **ttydev)
119{ 127 {
120 int pfd; 128 int pfd;
129 char *slave;
121 130
122 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 131 slave = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
123 if (*ttydev != NULL) 132
133 if (slave != NULL)
134 {
135 *ttydev = strdup (slave);
124 return pfd; 136 return pfd;
137 }
125 138
126 return -1; 139 return -1;
127} 140 }
141
128#elif defined(HAVE_DEV_PTC) 142#elif defined(HAVE_DEV_PTC)
143
129static int 144 static int
130get_pty (int *fd_tty, char **ttydev) 145 get_pty (int *fd_tty, char **ttydev)
131{ 146 {
132 int pfd; 147 int pfd;
133 148
134 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 149 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
135 { 150 {
136 *ttydev = strdup (ttyname (pfd)); 151 *ttydev = strdup (ttyname (pfd));
137 return pfd; 152 return pfd;
138 } 153 }
139 154
140 return -1; 155 return -1;
141} 156 }
157
142#elif defined(HAVE_DEV_CLONE) 158#elif defined(HAVE_DEV_CLONE)
159
143static int 160 static int
144get_pty (int *fd_tty, char **ttydev) 161 get_pty (int *fd_tty, char **ttydev)
145{ 162 {
146 int pfd; 163 int pfd;
147 164
148 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)
149 { 166 {
150 *ttydev = strdup (ptsname (pfd)); 167 *ttydev = strdup (ptsname (pfd));
151 return pfd; 168 return pfd;
152 } 169 }
153 170
154 return -1; 171 return -1;
155} 172 }
173
156#else 174#else
175
157/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 176 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
158static int 177 static int
159get_pty (int *fd_tty, char **ttydev) 178 get_pty (int *fd_tty, char **ttydev)
160{ 179 {
161 int pfd; 180 int pfd;
162 int i; 181 int i;
163 char pty_name[32]; 182 char pty_name[32];
164 char tty_name[32]; 183 char tty_name[32];
165 const char *majors = "pqrstuvwxyzabcde"; 184 const char *majors = "pqrstuvwxyzabcde";
166 const char *minors = "0123456789abcdef"; 185 const char *minors = "0123456789abcdef";
186
167 for (i = 0; i < 256; i++) 187 for (i = 0; i < 256; i++)
168 { 188 {
169 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]);
170 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
171 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 192 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
172 { 193 {
173 snprintf(pty_name, 32, "/dev/ptyp%d", i); 194 snprintf(pty_name, 32, "/dev/ptyp%d", i);
174 snprintf(tty_name, 32, "/dev/ttyp%d", i); 195 snprintf(tty_name, 32, "/dev/ttyp%d", i);
175 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 196 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
176 continue; 197 continue;
177 } 198 }
199
178 if (access (tty_name, R_OK | W_OK) == 0) 200 if (access (tty_name, R_OK | W_OK) == 0)
179 { 201 {
180 *ttydev = strdup (tty_name); 202 *ttydev = strdup (tty_name);
181 return pfd; 203 return pfd;
182 } 204 }
183 205
184 close (pfd); 206 close (pfd);
185 } 207 }
186} 208
209 return -1;
210 }
211
187#endif 212#endif
188 213
189/*----------------------------------------------------------------------*/ 214/*----------------------------------------------------------------------*/
190/* 215/*
191 * Returns tty file descriptor, or -1 on failure 216 * Returns tty file descriptor, or -1 on failure
192 */ 217 */
193static int 218static int
194get_tty (char *ttydev) 219get_tty (char *ttydev)
195{ 220{
196 return open (ttydev, O_RDWR | O_NOCTTY, 0); 221 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
201 * 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
202 */ 227 */
203static int 228static int
204control_tty (int fd_tty) 229control_tty (int fd_tty)
205{ 230{
231 int fd;
232
206 setsid (); 233 setsid ();
207 234
208#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 235#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
209 /* 236 /*
210 * Push STREAMS modules: 237 * Push STREAMS modules:
… …
231 ioctl (fd_tty, I_PUSH, "ldterm"); 258 ioctl (fd_tty, I_PUSH, "ldterm");
232 ioctl (fd_tty, I_PUSH, "ttcompat"); 259 ioctl (fd_tty, I_PUSH, "ttcompat");
233 } 260 }
234#endif 261#endif
235 262
263#ifdef TIOCSCTTY
236 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
237 270
238 int fd = open ("/dev/tty", O_WRONLY); 271 fd = open ("/dev/tty", O_WRONLY);
239 if (fd < 0) 272 if (fd < 0)
240 return -1; /* fatal */ 273 return -1; /* fatal */
241 274
242 close (fd); 275 close (fd);
243 276
… …
295 { 328 {
296#ifdef TTY_GID_SUPPORT 329#ifdef TTY_GID_SUPPORT
297 struct group *gr = getgrnam ("tty"); 330 struct group *gr = getgrnam ("tty");
298 331
299 if (gr) 332 if (gr)
333 {
300 { /* change group ownership of tty to "tty" */ 334 /* change group ownership of tty to "tty" */
301 mode = S_IRUSR | S_IWUSR | S_IWGRP; 335 mode = S_IRUSR | S_IWUSR | S_IWGRP;
302 gid = gr->gr_gid; 336 gid = gr->gr_gid;
303 } 337 }
304 else 338 else
305#endif /* TTY_GID_SUPPORT */ 339#endif /* TTY_GID_SUPPORT */
306 { 340 {
307 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 341 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
308 gid = 0; 342 gid = 0;
309 } 343 }
310 } 344 }
… …
327} 361}
328 362
329void 363void
330ptytty_unix::put () 364ptytty_unix::put ()
331{ 365{
366 if (name)
367 {
332 chmod (name, RESTORE_TTY_MODE); 368 chmod (name, RESTORE_TTY_MODE);
333 chown (name, 0, ttyconf.gid); 369 chown (name, 0, ttyconf.gid);
370 }
334 371
335 close_tty (); 372 close_tty ();
336 373
337 if (pty >= 0) 374 if (pty >= 0)
338 close (pty); 375 close (pty);
… …
371 } 408 }
372 409
373 return true; 410 return true;
374} 411}
375 412
376#if PTYTTY_HELPER
377
378static int sock_fd = -1;
379static int helper_pid, owner_pid;
380
381struct command
382{
383 enum { get, login, destroy } type;
384
385 ptytty *id;
386
387 bool login_shell;
388 int cmd_pid;
389 char hostname[512]; // arbitrary, but should be plenty
390};
391
392struct ptytty_proxy : ptytty
393{
394 ptytty *id;
395
396 ptytty_proxy ()
397 : id(0)
398 {
399 }
400
401 ~ptytty_proxy ();
402
403 bool get ();
404 void login (int cmd_pid, bool login_shell, const char *hostname);
405};
406
407bool
408ptytty_proxy::get ()
409{
410 command cmd;
411
412 cmd.type = command::get;
413
414 write (sock_fd, &cmd, sizeof (cmd));
415
416 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
417 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
418
419 if (!id)
420 return false;
421
422 if ((pty = recv_fd (sock_fd)) < 0
423 || (tty = recv_fd (sock_fd)) < 0)
424 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
425
426 return true;
427}
428
429void
430ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
431{
432 command cmd;
433
434 cmd.type = command::login;
435 cmd.id = id;
436 cmd.cmd_pid = cmd_pid;
437 cmd.login_shell = login_shell;
438 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
439
440 write (sock_fd, &cmd, sizeof (cmd));
441}
442
443ptytty_proxy::~ptytty_proxy ()
444{
445 if (id)
446 {
447 command cmd;
448
449 cmd.type = command::destroy;
450 cmd.id = id;
451
452 write (sock_fd, &cmd, sizeof (cmd));
453 }
454}
455
456static
457void serve ()
458{
459 command cmd;
460 vector<ptytty *> ptys;
461
462 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
463 {
464 if (cmd.type == command::get)
465 {
466 // -> id ptyfd ttyfd
467 cmd.id = new ptytty_unix;
468
469 if (cmd.id->get ())
470 {
471 write (sock_fd, &cmd.id, sizeof (cmd.id));
472 ptys.push_back (cmd.id);
473
474 ptytty::send_fd (sock_fd, cmd.id->pty);
475 ptytty::send_fd (sock_fd, cmd.id->tty);
476 }
477 else
478 {
479 delete cmd.id;
480 cmd.id = 0;
481 write (sock_fd, &cmd.id, sizeof (cmd.id));
482 }
483 }
484 else if (cmd.type == command::login)
485 {
486#if UTMP_SUPPORT
487 if (find (ptys.begin (), ptys.end (), cmd.id))
488 {
489 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
490 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
491 }
492#endif
493 }
494 else if (cmd.type == command::destroy)
495 {
496 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
497
498 if (pty != ptys.end ())
499 {
500 delete *pty;
501 ptys.erase (pty);
502 }
503 }
504 else
505 break;
506 }
507
508 // destroy all ptys
509 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
510 delete *i;
511}
512
513void
514ptytty::use_helper ()
515{
516 int pid = getpid ();
517
518 if (sock_fd >= 0 && pid == owner_pid)
519 return;
520
521 owner_pid = pid;
522
523 int sv[2];
524
525 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
526 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
527
528 helper_pid = fork ();
529
530 if (helper_pid < 0)
531 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
532
533 if (helper_pid)
534 {
535 // client, process
536 sock_fd = sv[0];
537 close (sv[1]);
538 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
539 }
540 else
541 {
542 // server, pty-helper
543 sock_fd = sv[1];
544
545 chdir ("/");
546
547 for (int fd = 0; fd < 1023; fd++)
548 if (fd != sock_fd)
549 close (fd);
550
551 serve ();
552 _exit (EXIT_SUCCESS);
553 }
554}
555
556#endif
557
558ptytty *
559ptytty::create ()
560{
561#if PTYTTY_HELPER
562 if (helper_pid && getpid () == owner_pid)
563 // use helper process
564 return new ptytty_proxy;
565 else
566#endif
567 return new ptytty_unix;
568}
569
570void
571ptytty::init ()
572{
573 uid_t uid = getuid ();
574 gid_t gid = getgid ();
575
576 // before doing anything else, check for setuid/setgid operation,
577 // start the helper process and drop privileges
578 if (uid != geteuid ()
579 || gid != getegid ())
580 {
581#if PTYTTY_HELPER
582 use_helper ();
583#else
584 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
585#endif
586
587 drop_privileges ();
588 }
589}
590
591void
592ptytty::drop_privileges ()
593{
594 uid_t uid = getuid ();
595 gid_t gid = getgid ();
596
597 // drop privileges
598#if HAVE_SETRESUID
599 setresgid (gid, gid, gid);
600 setresuid (uid, uid, uid);
601#elif HAVE_SETREUID
602 setregid (gid, gid);
603 setreuid (uid, uid);
604#elif HAVE_SETUID
605 setgid (gid);
606 setuid (uid);
607#endif
608
609 if (uid != geteuid ()
610 || gid != getegid ())
611 ptytty_fatal ("unable to drop privileges, aborting.\n");
612}
613

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