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Comparing rxvt-unicode/src/ptytty.C (file contents):
Revision 1.58 by root, Sun Jan 22 12:23:55 2006 UTC vs.
Revision 1.68 by ayin, Tue Dec 11 21:49:12 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)
91 {
89 { /* slave now unlocked */ 92 /* slave now unlocked */
90 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 93 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
91 return pfd; 94 return pfd;
92 } 95 }
93 96
94 close (pfd); 97 close (pfd);
95 } 98 }
96 99
97 return -1; 100 return -1;
98} 101 }
102
99#elif defined(HAVE_OPENPTY) 103#elif defined(HAVE_OPENPTY)
104
100static int 105 static int
101get_pty (int *fd_tty, char **ttydev) 106 get_pty (int *fd_tty, char **ttydev)
102{ 107 {
103 int pfd; 108 int pfd;
104 int res; 109 int res;
105 char tty_name[32]; 110
106
107 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 111 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
112
108 if (res != -1) 113 if (res != -1)
109 { 114 {
115 *ttydev = strdup (ttyname (*fd_tty));
116 return pfd;
117 }
118
119 return -1;
120 }
121
122#elif defined(HAVE__GETPTY)
123
124 static int
125 get_pty (int *fd_tty, char **ttydev)
126 {
127 int pfd;
128 char *slave;
129
130 slave = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
131
132 if (slave != NULL) {
110 *ttydev = strdup (tty_name); 133 *ttydev = strdup (slave);
111 return pfd; 134 return pfd;
112 } 135 }
113 136
114 return -1; 137 return -1;
115} 138 }
116#elif defined(HAVE__GETPTY)
117static int
118get_pty (int *fd_tty, char **ttydev)
119{
120 int pfd;
121 139
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) 140#elif defined(HAVE_DEV_PTC)
141
129static int 142 static int
130get_pty (int *fd_tty, char **ttydev) 143 get_pty (int *fd_tty, char **ttydev)
131{ 144 {
132 int pfd; 145 int pfd;
133 146
134 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 147 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
135 { 148 {
136 *ttydev = strdup (ttyname (pfd)); 149 *ttydev = strdup (ttyname (pfd));
137 return pfd; 150 return pfd;
138 } 151 }
139 152
140 return -1; 153 return -1;
141} 154 }
155
142#elif defined(HAVE_DEV_CLONE) 156#elif defined(HAVE_DEV_CLONE)
157
143static int 158 static int
144get_pty (int *fd_tty, char **ttydev) 159 get_pty (int *fd_tty, char **ttydev)
145{ 160 {
146 int pfd; 161 int pfd;
147 162
148 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0) 163 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
149 { 164 {
150 *ttydev = strdup (ptsname (pfd)); 165 *ttydev = strdup (ptsname (pfd));
151 return pfd; 166 return pfd;
152 } 167 }
153 168
154 return -1; 169 return -1;
155} 170 }
171
156#else 172#else
173
157/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 174 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
158static int 175 static int
159get_pty (int *fd_tty, char **ttydev) 176 get_pty (int *fd_tty, char **ttydev)
160{ 177 {
161 int pfd; 178 int pfd;
162 int i; 179 int i;
163 char pty_name[32]; 180 char pty_name[32];
164 char tty_name[32]; 181 char tty_name[32];
165 const char *majors = "pqrstuvwxyzabcde"; 182 const char *majors = "pqrstuvwxyzabcde";
166 const char *minors = "0123456789abcdef"; 183 const char *minors = "0123456789abcdef";
184
167 for (i = 0; i < 256; i++) 185 for (i = 0; i < 256; i++)
168 { 186 {
169 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 187 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]); 188 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
189
171 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 190 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
172 { 191 {
173 snprintf(pty_name, 32, "/dev/ptyp%d", i); 192 snprintf(pty_name, 32, "/dev/ptyp%d", i);
174 snprintf(tty_name, 32, "/dev/ttyp%d", i); 193 snprintf(tty_name, 32, "/dev/ttyp%d", i);
175 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 194 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
176 continue; 195 continue;
177 } 196 }
197
178 if (access (tty_name, R_OK | W_OK) == 0) 198 if (access (tty_name, R_OK | W_OK) == 0)
179 { 199 {
180 *ttydev = strdup (tty_name); 200 *ttydev = strdup (tty_name);
181 return pfd; 201 return pfd;
182 } 202 }
183 203
184 close (pfd); 204 close (pfd);
185 } 205 }
186} 206
207 return -1;
208 }
209
187#endif 210#endif
188 211
189/*----------------------------------------------------------------------*/ 212/*----------------------------------------------------------------------*/
190/* 213/*
191 * Returns tty file descriptor, or -1 on failure 214 * Returns tty file descriptor, or -1 on failure
192 */ 215 */
193static int 216static int
194get_tty (char *ttydev) 217get_tty (char *ttydev)
195{ 218{
196 return open (ttydev, O_RDWR | O_NOCTTY, 0); 219 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
201 * Make our tty a controlling tty so that /dev/tty points to us 224 * Make our tty a controlling tty so that /dev/tty points to us
202 */ 225 */
203static int 226static int
204control_tty (int fd_tty) 227control_tty (int fd_tty)
205{ 228{
229 int fd;
230
206 setsid (); 231 setsid ();
207 232
208#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 233#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
209 /* 234 /*
210 * Push STREAMS modules: 235 * Push STREAMS modules:
… …
231 ioctl (fd_tty, I_PUSH, "ldterm"); 256 ioctl (fd_tty, I_PUSH, "ldterm");
232 ioctl (fd_tty, I_PUSH, "ttcompat"); 257 ioctl (fd_tty, I_PUSH, "ttcompat");
233 } 258 }
234#endif 259#endif
235 260
261#ifdef TIOCSCTTY
236 ioctl (fd_tty, TIOCSCTTY, NULL); 262 ioctl (fd_tty, TIOCSCTTY, NULL);
263#else
264 fd = open (ttyname (fd_tty), O_RDWR);
265 if (fd >= 0)
266 close (fd);
267#endif
237 268
238 int fd = open ("/dev/tty", O_WRONLY); 269 fd = open ("/dev/tty", O_WRONLY);
239 if (fd < 0) 270 if (fd < 0)
240 return -1; /* fatal */ 271 return -1; /* fatal */
241 272
242 close (fd); 273 close (fd);
243 274
… …
295 { 326 {
296#ifdef TTY_GID_SUPPORT 327#ifdef TTY_GID_SUPPORT
297 struct group *gr = getgrnam ("tty"); 328 struct group *gr = getgrnam ("tty");
298 329
299 if (gr) 330 if (gr)
331 {
300 { /* change group ownership of tty to "tty" */ 332 /* change group ownership of tty to "tty" */
301 mode = S_IRUSR | S_IWUSR | S_IWGRP; 333 mode = S_IRUSR | S_IWUSR | S_IWGRP;
302 gid = gr->gr_gid; 334 gid = gr->gr_gid;
303 } 335 }
304 else 336 else
305#endif /* TTY_GID_SUPPORT */ 337#endif /* TTY_GID_SUPPORT */
306 { 338 {
307 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 339 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
308 gid = 0; 340 gid = 0;
309 } 341 }
310 } 342 }
… …
327} 359}
328 360
329void 361void
330ptytty_unix::put () 362ptytty_unix::put ()
331{ 363{
364 if (name)
365 {
332 chmod (name, RESTORE_TTY_MODE); 366 chmod (name, RESTORE_TTY_MODE);
333 chown (name, 0, ttyconf.gid); 367 chown (name, 0, ttyconf.gid);
368 }
334 369
335 close_tty (); 370 close_tty ();
336 371
337 if (pty >= 0) 372 if (pty >= 0)
338 close (pty); 373 close (pty);
… …
371 } 406 }
372 407
373 return true; 408 return true;
374} 409}
375 410
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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