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comparison sshpty.c @ 285:1b9e69c058d2

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propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3) to branch 'au.asn.ucc.matt.dropbear' (head fdf4a7a3b97ae5046139915de7e40399cceb2c01)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:58 +0000
parents 5c6f9d27ea1c
children 740e782679be a98a2138364a
comparison
equal deleted inserted replaced
281:997e6f7dc01e 285:1b9e69c058d2
1 /*
2 * Dropbear - a SSH2 server
3 *
4 * Copied from OpenSSH-3.5p1 source, modified by Matt Johnston 2003
5 *
6 * Author: Tatu Ylonen <[email protected]>
7 * Copyright (c) 1995 Tatu Ylonen <[email protected]>, Espoo, Finland
8 * All rights reserved
9 * Allocating a pseudo-terminal, and making it the controlling tty.
10 *
11 * As far as I am concerned, the code I have written for this software
12 * can be used freely for any purpose. Any derived versions of this
13 * software must be clearly marked as such, and if the derived work is
14 * incompatible with the protocol description in the RFC file, it must be
15 * called by a name other than "ssh" or "Secure Shell".
16 */
17
18 /*RCSID("OpenBSD: sshpty.c,v 1.7 2002/06/24 17:57:20 deraadt Exp ");*/
19
20 #include "includes.h"
21 #include "dbutil.h"
22 #include "errno.h"
23 #include "sshpty.h"
24
25 /* Pty allocated with _getpty gets broken if we do I_PUSH:es to it. */
26 #if defined(HAVE__GETPTY) || defined(HAVE_OPENPTY)
27 #undef HAVE_DEV_PTMX
28 #endif
29
30 #ifdef HAVE_PTY_H
31 # include <pty.h>
32 #endif
33 #if defined(USE_DEV_PTMX) && defined(HAVE_STROPTS_H)
34 # include <stropts.h>
35 #endif
36
37 #ifndef O_NOCTTY
38 #define O_NOCTTY 0
39 #endif
40
41 /*
42 * Allocates and opens a pty. Returns 0 if no pty could be allocated, or
43 * nonzero if a pty was successfully allocated. On success, open file
44 * descriptors for the pty and tty sides and the name of the tty side are
45 * returned (the buffer must be able to hold at least 64 characters).
46 */
47
48 int
49 pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen)
50 {
51 #if defined(HAVE_OPENPTY)
52 /* exists in recent (4.4) BSDs and OSF/1 */
53 char *name;
54 int i;
55
56 i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
57 if (i < 0) {
58 dropbear_log(LOG_WARNING,
59 "pty_allocate: openpty: %.100s", strerror(errno));
60 return 0;
61 }
62 name = ttyname(*ttyfd);
63 if (!name) {
64 dropbear_exit("ttyname fails for openpty device");
65 }
66
67 strlcpy(namebuf, name, namebuflen); /* possible truncation */
68 return 1;
69 #else /* HAVE_OPENPTY */
70 #ifdef HAVE__GETPTY
71 /*
72 * _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more
73 * pty's automagically when needed
74 */
75 char *slave;
76
77 slave = _getpty(ptyfd, O_RDWR, 0622, 0);
78 if (slave == NULL) {
79 dropbear_log(LOG_WARNING,
80 "pty_allocate: _getpty: %.100s", strerror(errno));
81 return 0;
82 }
83 strlcpy(namebuf, slave, namebuflen);
84 /* Open the slave side. */
85 *ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
86 if (*ttyfd < 0) {
87 dropbear_log(LOG_WARNING,
88 "pty_allocate error: ttyftd open error");
89 close(*ptyfd);
90 return 0;
91 }
92 return 1;
93 #else /* HAVE__GETPTY */
94 #if defined(USE_DEV_PTMX)
95 /*
96 * This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3
97 * also has bsd-style ptys, but they simply do not work.)
98 *
99 * Linux systems may have the /dev/ptmx device, but this code won't work.
100 */
101 int ptm;
102 char *pts;
103
104 ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY);
105 if (ptm < 0) {
106 dropbear_log(LOG_WARNING,
107 "pty_allocate: /dev/ptmx: %.100s", strerror(errno));
108 return 0;
109 }
110 if (grantpt(ptm) < 0) {
111 dropbear_log(LOG_WARNING,
112 "grantpt: %.100s", strerror(errno));
113 return 0;
114 }
115 if (unlockpt(ptm) < 0) {
116 dropbear_log(LOG_WARNING,
117 "unlockpt: %.100s", strerror(errno));
118 return 0;
119 }
120 pts = ptsname(ptm);
121 if (pts == NULL) {
122 dropbear_log(LOG_WARNING,
123 "Slave pty side name could not be obtained.");
124 }
125 strlcpy(namebuf, pts, namebuflen);
126 *ptyfd = ptm;
127
128 /* Open the slave side. */
129 *ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
130 if (*ttyfd < 0) {
131 dropbear_log(LOG_ERR,
132 "error opening pts %.100s: %.100s", namebuf, strerror(errno));
133 close(*ptyfd);
134 return 0;
135 }
136 #ifndef HAVE_CYGWIN
137 /*
138 * Push the appropriate streams modules, as described in Solaris pts(7).
139 * HP-UX pts(7) doesn't have ttcompat module.
140 */
141 if (ioctl(*ttyfd, I_PUSH, "ptem") < 0) {
142 dropbear_log(LOG_WARNING,
143 "ioctl I_PUSH ptem: %.100s", strerror(errno));
144 }
145 if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0) {
146 dropbear_log(LOG_WARNING,
147 "ioctl I_PUSH ldterm: %.100s", strerror(errno));
148 }
149 #ifndef __hpux
150 if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0) {
151 dropbear_log(LOG_WARNING,
152 "ioctl I_PUSH ttcompat: %.100s", strerror(errno));
153 }
154 #endif
155 #endif
156 return 1;
157 #else /* USE_DEV_PTMX */
158 #ifdef HAVE_DEV_PTS_AND_PTC
159 /* AIX-style pty code. */
160 const char *name;
161
162 *ptyfd = open("/dev/ptc", O_RDWR | O_NOCTTY);
163 if (*ptyfd < 0) {
164 dropbear_log(LOG_ERR,
165 "Could not open /dev/ptc: %.100s", strerror(errno));
166 return 0;
167 }
168 name = ttyname(*ptyfd);
169 if (!name) {
170 dropbear_exit("ttyname fails for /dev/ptc device");
171 }
172 strlcpy(namebuf, name, namebuflen);
173 *ttyfd = open(name, O_RDWR | O_NOCTTY);
174 if (*ttyfd < 0) {
175 dropbear_log(LOG_ERR,
176 "Could not open pty slave side %.100s: %.100s",
177 name, strerror(errno));
178 close(*ptyfd);
179 return 0;
180 }
181 return 1;
182 #else /* HAVE_DEV_PTS_AND_PTC */
183
184 /* BSD-style pty code. */
185 char buf[64];
186 int i;
187 const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ";
188 const char *ptyminors = "0123456789abcdef";
189 int num_minors = strlen(ptyminors);
190 int num_ptys = strlen(ptymajors) * num_minors;
191 struct termios tio;
192
193 for (i = 0; i < num_ptys; i++) {
194 snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors],
195 ptyminors[i % num_minors]);
196 snprintf(namebuf, namebuflen, "/dev/tty%c%c",
197 ptymajors[i / num_minors], ptyminors[i % num_minors]);
198
199 *ptyfd = open(buf, O_RDWR | O_NOCTTY);
200 if (*ptyfd < 0) {
201 /* Try SCO style naming */
202 snprintf(buf, sizeof buf, "/dev/ptyp%d", i);
203 snprintf(namebuf, namebuflen, "/dev/ttyp%d", i);
204 *ptyfd = open(buf, O_RDWR | O_NOCTTY);
205 if (*ptyfd < 0) {
206 continue;
207 }
208 }
209
210 /* Open the slave side. */
211 *ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
212 if (*ttyfd < 0) {
213 dropbear_log(LOG_ERR,
214 "pty_allocate: %.100s: %.100s", namebuf, strerror(errno));
215 close(*ptyfd);
216 return 0;
217 }
218 /* set tty modes to a sane state for broken clients */
219 if (tcgetattr(*ptyfd, &tio) < 0) {
220 dropbear_log(LOG_WARNING,
221 "ptyallocate: tty modes failed: %.100s", strerror(errno));
222 } else {
223 tio.c_lflag |= (ECHO | ISIG | ICANON);
224 tio.c_oflag |= (OPOST | ONLCR);
225 tio.c_iflag |= ICRNL;
226
227 /* Set the new modes for the terminal. */
228 if (tcsetattr(*ptyfd, TCSANOW, &tio) < 0) {
229 dropbear_log(LOG_WARNING,
230 "Setting tty modes for pty failed: %.100s",
231 strerror(errno));
232 }
233 }
234
235 return 1;
236 }
237 dropbear_log(LOG_WARNING, "failed to open any /dev/pty?? devices");
238 return 0;
239 #endif /* HAVE_DEV_PTS_AND_PTC */
240 #endif /* USE_DEV_PTMX */
241 #endif /* HAVE__GETPTY */
242 #endif /* HAVE_OPENPTY */
243 }
244
245 /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */
246
247 void
248 pty_release(const char *tty_name)
249 {
250 if (chown(tty_name, (uid_t) 0, (gid_t) 0) < 0
251 && (errno != ENOENT)) {
252 dropbear_log(LOG_ERR,
253 "chown %.100s 0 0 failed: %.100s", tty_name, strerror(errno));
254 }
255 if (chmod(tty_name, (mode_t) 0666) < 0
256 && (errno != ENOENT)) {
257 dropbear_log(LOG_ERR,
258 "chmod %.100s 0666 failed: %.100s", tty_name, strerror(errno));
259 }
260 }
261
262 /* Makes the tty the processes controlling tty and sets it to sane modes. */
263
264 void
265 pty_make_controlling_tty(int *ttyfd, const char *tty_name)
266 {
267 int fd;
268 #ifdef USE_VHANGUP
269 void *old;
270 #endif /* USE_VHANGUP */
271
272 /* Solaris has a problem with TIOCNOTTY for a bg process, so
273 * we disable the signal which would STOP the process - matt */
274 signal(SIGTTOU, SIG_IGN);
275
276 /* First disconnect from the old controlling tty. */
277 #ifdef TIOCNOTTY
278 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
279 if (fd >= 0) {
280 (void) ioctl(fd, TIOCNOTTY, NULL);
281 close(fd);
282 }
283 #endif /* TIOCNOTTY */
284 if (setsid() < 0) {
285 dropbear_log(LOG_ERR,
286 "setsid: %.100s", strerror(errno));
287 }
288
289 /*
290 * Verify that we are successfully disconnected from the controlling
291 * tty.
292 */
293 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
294 if (fd >= 0) {
295 dropbear_log(LOG_ERR,
296 "Failed to disconnect from controlling tty.\n");
297 close(fd);
298 }
299 /* Make it our controlling tty. */
300 #ifdef TIOCSCTTY
301 if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) {
302 dropbear_log(LOG_ERR,
303 "ioctl(TIOCSCTTY): %.100s", strerror(errno));
304 }
305 #endif /* TIOCSCTTY */
306 #ifdef HAVE_NEWS4
307 if (setpgrp(0,0) < 0) {
308 dropbear_log(LOG_ERR,
309 error("SETPGRP %s",strerror(errno)));
310 }
311 #endif /* HAVE_NEWS4 */
312 #ifdef USE_VHANGUP
313 old = mysignal(SIGHUP, SIG_IGN);
314 vhangup();
315 mysignal(SIGHUP, old);
316 #endif /* USE_VHANGUP */
317 fd = open(tty_name, O_RDWR);
318 if (fd < 0) {
319 dropbear_log(LOG_ERR,
320 "%.100s: %.100s", tty_name, strerror(errno));
321 } else {
322 #ifdef USE_VHANGUP
323 close(*ttyfd);
324 *ttyfd = fd;
325 #else /* USE_VHANGUP */
326 close(fd);
327 #endif /* USE_VHANGUP */
328 }
329 /* Verify that we now have a controlling tty. */
330 fd = open(_PATH_TTY, O_WRONLY);
331 if (fd < 0) {
332 dropbear_log(LOG_ERR,
333 "open /dev/tty failed - could not set controlling tty: %.100s",
334 strerror(errno));
335 } else {
336 close(fd);
337 }
338 }
339
340 /* Changes the window size associated with the pty. */
341
342 void
343 pty_change_window_size(int ptyfd, int row, int col,
344 int xpixel, int ypixel)
345 {
346 struct winsize w;
347
348 w.ws_row = row;
349 w.ws_col = col;
350 w.ws_xpixel = xpixel;
351 w.ws_ypixel = ypixel;
352 (void) ioctl(ptyfd, TIOCSWINSZ, &w);
353 }
354
355 void
356 pty_setowner(struct passwd *pw, const char *tty_name)
357 {
358 struct group *grp;
359 gid_t gid;
360 mode_t mode;
361 struct stat st;
362
363 /* Determine the group to make the owner of the tty. */
364 grp = getgrnam("tty");
365 if (grp) {
366 gid = grp->gr_gid;
367 mode = S_IRUSR | S_IWUSR | S_IWGRP;
368 } else {
369 gid = pw->pw_gid;
370 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
371 }
372
373 /*
374 * Change owner and mode of the tty as required.
375 * Warn but continue if filesystem is read-only and the uids match/
376 * tty is owned by root.
377 */
378 if (stat(tty_name, &st)) {
379 dropbear_exit("pty_setowner: stat(%.101s) failed: %.100s",
380 tty_name, strerror(errno));
381 }
382
383 if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
384 if (chown(tty_name, pw->pw_uid, gid) < 0) {
385 if (errno == EROFS &&
386 (st.st_uid == pw->pw_uid || st.st_uid == 0)) {
387 dropbear_log(LOG_ERR,
388 "chown(%.100s, %u, %u) failed: %.100s",
389 tty_name, (unsigned int)pw->pw_uid, (unsigned int)gid,
390 strerror(errno));
391 } else {
392 dropbear_exit("chown(%.100s, %u, %u) failed: %.100s",
393 tty_name, (unsigned int)pw->pw_uid, (unsigned int)gid,
394 strerror(errno));
395 }
396 }
397 }
398
399 if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
400 if (chmod(tty_name, mode) < 0) {
401 if (errno == EROFS &&
402 (st.st_mode & (S_IRGRP | S_IROTH)) == 0) {
403 dropbear_log(LOG_ERR,
404 "chmod(%.100s, 0%o) failed: %.100s",
405 tty_name, mode, strerror(errno));
406 } else {
407 dropbear_exit("chmod(%.100s, 0%o) failed: %.100s",
408 tty_name, mode, strerror(errno));
409 }
410 }
411 }
412 }