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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11003 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * Allocating a pseudo-terminal, and making it the controlling tty.
Damien Miller4af51302000-04-16 11:18:38 +10006 *
Damien Millere4340be2000-09-16 13:29:08 +11007 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
Damien Miller95def091999-11-25 00:26:21 +110012 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100013
14#include "includes.h"
Ben Lindstrom6ed8c042001-03-05 03:53:02 +000015RCSID("$OpenBSD: sshpty.c,v 1.1 2001/03/04 01:46:30 djm Exp $");
Damien Miller95def091999-11-25 00:26:21 +110016
Damien Miller36b339a1999-12-14 10:54:47 +110017#ifdef HAVE_UTIL_H
18# include <util.h>
19#endif /* HAVE_UTIL_H */
20
Ben Lindstromd95c09c2001-02-18 19:13:33 +000021#include "sshpty.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000022#include "log.h"
Damien Miller356a0b01999-11-08 15:30:59 +110023
Damien Millerd4a8b7e1999-10-27 13:42:43 +100024/* Pty allocated with _getpty gets broken if we do I_PUSH:es to it. */
25#if defined(HAVE__GETPTY) || defined(HAVE_OPENPTY)
26#undef HAVE_DEV_PTMX
27#endif
28
Damien Millerfce16481999-12-08 08:53:52 +110029#ifdef HAVE_PTY_H
30# include <pty.h>
31#endif
32#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H)
33# include <sys/stropts.h>
34#endif
35
Damien Millerd4a8b7e1999-10-27 13:42:43 +100036#ifndef O_NOCTTY
37#define O_NOCTTY 0
38#endif
39
Damien Miller5428f641999-11-25 11:54:57 +110040/*
41 * Allocates and opens a pty. Returns 0 if no pty could be allocated, or
42 * nonzero if a pty was successfully allocated. On success, open file
43 * descriptors for the pty and tty sides and the name of the tty side are
44 * returned (the buffer must be able to hold at least 64 characters).
45 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100046
Damien Miller4af51302000-04-16 11:18:38 +100047int
Damien Miller037a0dc1999-12-07 15:38:31 +110048pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100049{
Damien Miller037a0dc1999-12-07 15:38:31 +110050#if defined(HAVE_OPENPTY) || defined(BSD4_4)
Damien Miller95def091999-11-25 00:26:21 +110051 /* openpty(3) exists in OSF/1 and some other os'es */
Damien Miller99e92432001-02-18 12:49:35 +110052 char *name;
Damien Miller95def091999-11-25 00:26:21 +110053 int i;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100054
Damien Miller99e92432001-02-18 12:49:35 +110055 i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
Damien Miller95def091999-11-25 00:26:21 +110056 if (i < 0) {
57 error("openpty: %.100s", strerror(errno));
58 return 0;
59 }
Damien Miller99e92432001-02-18 12:49:35 +110060 name = ttyname(*ttyfd);
61 if (!name)
62 fatal("openpty returns device for which ttyname fails.");
63
64 strlcpy(namebuf, name, namebuflen); /* possible truncation */
Damien Miller95def091999-11-25 00:26:21 +110065 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100066#else /* HAVE_OPENPTY */
67#ifdef HAVE__GETPTY
Damien Miller5428f641999-11-25 11:54:57 +110068 /*
69 * _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more
70 * pty's automagically when needed
71 */
Damien Miller95def091999-11-25 00:26:21 +110072 char *slave;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100073
Damien Miller95def091999-11-25 00:26:21 +110074 slave = _getpty(ptyfd, O_RDWR, 0622, 0);
75 if (slave == NULL) {
76 error("_getpty: %.100s", strerror(errno));
77 return 0;
78 }
Damien Miller037a0dc1999-12-07 15:38:31 +110079 strlcpy(namebuf, slave, namebuflen);
Damien Miller95def091999-11-25 00:26:21 +110080 /* Open the slave side. */
81 *ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
82 if (*ttyfd < 0) {
83 error("%.200s: %.100s", namebuf, strerror(errno));
84 close(*ptyfd);
85 return 0;
86 }
87 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100088#else /* HAVE__GETPTY */
Damien Miller76112de1999-12-21 11:18:08 +110089#if defined(HAVE_DEV_PTMX)
Damien Miller5428f641999-11-25 11:54:57 +110090 /*
91 * This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3
92 * also has bsd-style ptys, but they simply do not work.)
93 */
Damien Miller95def091999-11-25 00:26:21 +110094 int ptm;
95 char *pts;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100096
Damien Miller95def091999-11-25 00:26:21 +110097 ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY);
98 if (ptm < 0) {
99 error("/dev/ptmx: %.100s", strerror(errno));
100 return 0;
101 }
102 if (grantpt(ptm) < 0) {
103 error("grantpt: %.100s", strerror(errno));
104 return 0;
105 }
106 if (unlockpt(ptm) < 0) {
107 error("unlockpt: %.100s", strerror(errno));
108 return 0;
109 }
110 pts = ptsname(ptm);
111 if (pts == NULL)
112 error("Slave pty side name could not be obtained.");
Damien Miller037a0dc1999-12-07 15:38:31 +1100113 strlcpy(namebuf, pts, namebuflen);
Damien Miller95def091999-11-25 00:26:21 +1100114 *ptyfd = ptm;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000115
Damien Miller95def091999-11-25 00:26:21 +1100116 /* Open the slave side. */
117 *ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
118 if (*ttyfd < 0) {
119 error("%.100s: %.100s", namebuf, strerror(errno));
120 close(*ptyfd);
121 return 0;
122 }
Damien Millerbac2d8a2000-09-05 16:13:06 +1100123#ifndef HAVE_CYGWIN
Kevin Steves85b3db62000-11-05 15:31:36 +0000124 /*
125 * Push the appropriate streams modules, as described in Solaris pts(7).
126 * HP-UX pts(7) doesn't have ttcompat module.
127 */
Damien Miller95def091999-11-25 00:26:21 +1100128 if (ioctl(*ttyfd, I_PUSH, "ptem") < 0)
129 error("ioctl I_PUSH ptem: %.100s", strerror(errno));
130 if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0)
131 error("ioctl I_PUSH ldterm: %.100s", strerror(errno));
Kevin Steves85b3db62000-11-05 15:31:36 +0000132#ifndef __hpux
Damien Miller95def091999-11-25 00:26:21 +1100133 if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0)
134 error("ioctl I_PUSH ttcompat: %.100s", strerror(errno));
Damien Millere37ac5a2000-03-17 23:58:59 +1100135#endif
Damien Millerbac2d8a2000-09-05 16:13:06 +1100136#endif
Damien Miller95def091999-11-25 00:26:21 +1100137 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000138#else /* HAVE_DEV_PTMX */
139#ifdef HAVE_DEV_PTS_AND_PTC
Damien Miller95def091999-11-25 00:26:21 +1100140 /* AIX-style pty code. */
141 const char *name;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000142
Damien Miller95def091999-11-25 00:26:21 +1100143 *ptyfd = open("/dev/ptc", O_RDWR | O_NOCTTY);
144 if (*ptyfd < 0) {
145 error("Could not open /dev/ptc: %.100s", strerror(errno));
146 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000147 }
Damien Miller95def091999-11-25 00:26:21 +1100148 name = ttyname(*ptyfd);
149 if (!name)
150 fatal("Open of /dev/ptc returns device for which ttyname fails.");
Damien Miller037a0dc1999-12-07 15:38:31 +1100151 strlcpy(namebuf, name, namebuflen);
Damien Miller95def091999-11-25 00:26:21 +1100152 *ttyfd = open(name, O_RDWR | O_NOCTTY);
153 if (*ttyfd < 0) {
154 error("Could not open pty slave side %.100s: %.100s",
155 name, strerror(errno));
156 close(*ptyfd);
157 return 0;
158 }
159 return 1;
160#else /* HAVE_DEV_PTS_AND_PTC */
161 /* BSD-style pty code. */
162 char buf[64];
163 int i;
Damien Miller5428f641999-11-25 11:54:57 +1100164 const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ";
Damien Miller95def091999-11-25 00:26:21 +1100165 const char *ptyminors = "0123456789abcdef";
166 int num_minors = strlen(ptyminors);
167 int num_ptys = strlen(ptymajors) * num_minors;
168
169 for (i = 0; i < num_ptys; i++) {
170 snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors],
171 ptyminors[i % num_minors]);
Damien Millera34a28b1999-12-14 10:47:15 +1100172 snprintf(namebuf, namebuflen, "/dev/tty%c%c",
Damien Miller037a0dc1999-12-07 15:38:31 +1100173 ptymajors[i / num_minors], ptyminors[i % num_minors]);
Damien Miller95def091999-11-25 00:26:21 +1100174
Damien Miller6d8c11f2000-08-29 11:52:38 +1100175 *ptyfd = open(buf, O_RDWR | O_NOCTTY);
176 if (*ptyfd < 0) {
177 /* Try SCO style naming */
178 snprintf(buf, sizeof buf, "/dev/ptyp%d", i);
179 snprintf(namebuf, namebuflen, "/dev/ttyp%d", i);
180 *ptyfd = open(buf, O_RDWR | O_NOCTTY);
181 if (*ptyfd < 0)
182 continue;
Kevin Stevesef4eea92001-02-05 12:42:17 +0000183 }
184
Damien Miller95def091999-11-25 00:26:21 +1100185 /* Open the slave side. */
186 *ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
187 if (*ttyfd < 0) {
188 error("%.100s: %.100s", namebuf, strerror(errno));
189 close(*ptyfd);
190 return 0;
191 }
192 return 1;
193 }
194 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000195#endif /* HAVE_DEV_PTS_AND_PTC */
196#endif /* HAVE_DEV_PTMX */
197#endif /* HAVE__GETPTY */
198#endif /* HAVE_OPENPTY */
199}
200
Damien Miller95def091999-11-25 00:26:21 +1100201/* Releases the tty. Its ownership is returned to root, and permissions to 0666. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000202
Damien Miller4af51302000-04-16 11:18:38 +1000203void
Damien Miller95def091999-11-25 00:26:21 +1100204pty_release(const char *ttyname)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000205{
Damien Miller204ad072000-03-02 23:56:12 +1100206 if (chown(ttyname, (uid_t) 0, (gid_t) 0) < 0)
Damien Millerc7d8dbb2000-03-02 23:30:53 +1100207 error("chown %.100s 0 0 failed: %.100s", ttyname, strerror(errno));
Damien Miller204ad072000-03-02 23:56:12 +1100208 if (chmod(ttyname, (mode_t) 0666) < 0)
Damien Millerc7d8dbb2000-03-02 23:30:53 +1100209 error("chmod %.100s 0666 failed: %.100s", ttyname, strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000210}
211
212/* Makes the tty the processes controlling tty and sets it to sane modes. */
213
Damien Miller4af51302000-04-16 11:18:38 +1000214void
Damien Miller95def091999-11-25 00:26:21 +1100215pty_make_controlling_tty(int *ttyfd, const char *ttyname)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000216{
Damien Miller95def091999-11-25 00:26:21 +1100217 int fd;
Damien Millerbac2d8a2000-09-05 16:13:06 +1100218#ifdef USE_VHANGUP
Damien Millerd0cff3e2000-04-20 23:12:58 +1000219 void *old;
Damien Millerbac2d8a2000-09-05 16:13:06 +1100220#endif /* USE_VHANGUP */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000221
Damien Miller95def091999-11-25 00:26:21 +1100222 /* First disconnect from the old controlling tty. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000223#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000224 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +1100225 if (fd >= 0) {
226 (void) ioctl(fd, TIOCNOTTY, NULL);
227 close(fd);
228 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000229#endif /* TIOCNOTTY */
Damien Miller95def091999-11-25 00:26:21 +1100230 if (setsid() < 0)
231 error("setsid: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000232
Damien Miller5428f641999-11-25 11:54:57 +1100233 /*
234 * Verify that we are successfully disconnected from the controlling
235 * tty.
236 */
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000237 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +1100238 if (fd >= 0) {
239 error("Failed to disconnect from controlling tty.");
240 close(fd);
241 }
242 /* Make it our controlling tty. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000243#ifdef TIOCSCTTY
Damien Miller95def091999-11-25 00:26:21 +1100244 debug("Setting controlling tty using TIOCSCTTY.");
Kevin Steves6c0d6272000-11-12 09:22:29 +0000245 if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
246 error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000247#endif /* TIOCSCTTY */
Ben Lindstromb5628642000-10-18 00:02:25 +0000248#ifdef HAVE_NEWS4
249 if (setpgrp(0,0) < 0)
250 error("SETPGRP %s",strerror(errno));
251#endif /* HAVE_NEWS4 */
Damien Millerbac2d8a2000-09-05 16:13:06 +1100252#ifdef USE_VHANGUP
Damien Millerd0cff3e2000-04-20 23:12:58 +1000253 old = signal(SIGHUP, SIG_IGN);
254 vhangup();
255 signal(SIGHUP, old);
Damien Millerbac2d8a2000-09-05 16:13:06 +1100256#endif /* USE_VHANGUP */
Damien Miller95def091999-11-25 00:26:21 +1100257 fd = open(ttyname, O_RDWR);
Damien Millerd0cff3e2000-04-20 23:12:58 +1000258 if (fd < 0) {
Damien Miller95def091999-11-25 00:26:21 +1100259 error("%.100s: %.100s", ttyname, strerror(errno));
Damien Millerd0cff3e2000-04-20 23:12:58 +1000260 } else {
Damien Millerbac2d8a2000-09-05 16:13:06 +1100261#ifdef USE_VHANGUP
Damien Millerd0cff3e2000-04-20 23:12:58 +1000262 close(*ttyfd);
263 *ttyfd = fd;
Damien Millerbac2d8a2000-09-05 16:13:06 +1100264#else /* USE_VHANGUP */
Damien Miller95def091999-11-25 00:26:21 +1100265 close(fd);
Damien Millerbac2d8a2000-09-05 16:13:06 +1100266#endif /* USE_VHANGUP */
Damien Millerd0cff3e2000-04-20 23:12:58 +1000267 }
Damien Miller95def091999-11-25 00:26:21 +1100268 /* Verify that we now have a controlling tty. */
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000269 fd = open(_PATH_TTY, O_WRONLY);
Damien Miller95def091999-11-25 00:26:21 +1100270 if (fd < 0)
271 error("open /dev/tty failed - could not set controlling tty: %.100s",
272 strerror(errno));
273 else {
274 close(fd);
275 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000276}
277
278/* Changes the window size associated with the pty. */
279
Damien Miller4af51302000-04-16 11:18:38 +1000280void
Damien Miller95def091999-11-25 00:26:21 +1100281pty_change_window_size(int ptyfd, int row, int col,
282 int xpixel, int ypixel)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000283{
Damien Miller95def091999-11-25 00:26:21 +1100284 struct winsize w;
285 w.ws_row = row;
286 w.ws_col = col;
287 w.ws_xpixel = xpixel;
288 w.ws_ypixel = ypixel;
289 (void) ioctl(ptyfd, TIOCSWINSZ, &w);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000290}
Damien Millerc7d8dbb2000-03-02 23:30:53 +1100291
292void
293pty_setowner(struct passwd *pw, const char *ttyname)
294{
295 struct group *grp;
296 gid_t gid;
297 mode_t mode;
Kevin Stevesfa72dda2000-12-15 18:39:12 +0000298 struct stat st;
Damien Millerc7d8dbb2000-03-02 23:30:53 +1100299
300 /* Determine the group to make the owner of the tty. */
301 grp = getgrnam("tty");
302 if (grp) {
303 gid = grp->gr_gid;
304 mode = S_IRUSR | S_IWUSR | S_IWGRP;
305 } else {
306 gid = pw->pw_gid;
307 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
308 }
309
Kevin Stevesfa72dda2000-12-15 18:39:12 +0000310 /*
311 * Change owner and mode of the tty as required.
312 * Warn but continue if filesystem is read-only and the uids match.
313 */
314 if (stat(ttyname, &st))
315 fatal("stat(%.100s) failed: %.100s", ttyname,
316 strerror(errno));
317
318 if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
319 if (chown(ttyname, pw->pw_uid, gid) < 0) {
320 if (errno == EROFS && st.st_uid == pw->pw_uid)
321 error("chown(%.100s, %d, %d) failed: %.100s",
Kevin Stevesef4eea92001-02-05 12:42:17 +0000322 ttyname, pw->pw_uid, gid,
Kevin Stevesfa72dda2000-12-15 18:39:12 +0000323 strerror(errno));
324 else
325 fatal("chown(%.100s, %d, %d) failed: %.100s",
Kevin Stevesef4eea92001-02-05 12:42:17 +0000326 ttyname, pw->pw_uid, gid,
Kevin Stevesfa72dda2000-12-15 18:39:12 +0000327 strerror(errno));
328 }
329 }
330
331 if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
332 if (chmod(ttyname, mode) < 0) {
333 if (errno == EROFS &&
334 (st.st_mode & (S_IRGRP | S_IROTH)) == 0)
335 error("chmod(%.100s, 0%o) failed: %.100s",
336 ttyname, mode, strerror(errno));
337 else
338 fatal("chmod(%.100s, 0%o) failed: %.100s",
339 ttyname, mode, strerror(errno));
340 }
341 }
Damien Millerc7d8dbb2000-03-02 23:30:53 +1100342}