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3c0ef626 | 1 | /* |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Allocating a pseudo-terminal, and making it the controlling tty. | |
6 | * | |
7 | * 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". | |
12 | */ | |
13 | ||
14 | #include "includes.h" | |
15 | RCSID("$OpenBSD: sshpty.c,v 1.3 2001/07/22 21:32:27 markus Exp $"); | |
16 | ||
17 | #ifdef HAVE_UTIL_H | |
18 | # include <util.h> | |
19 | #endif /* HAVE_UTIL_H */ | |
20 | ||
21 | #include "sshpty.h" | |
22 | #include "log.h" | |
23 | #include "misc.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(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) | |
34 | # include <sys/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) || defined(BSD4_4) | |
52 | /* openpty(3) exists in OSF/1 and some other os'es */ | |
53 | char *name; | |
54 | int i; | |
55 | ||
56 | i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); | |
57 | if (i < 0) { | |
58 | error("openpty: %.100s", strerror(errno)); | |
59 | return 0; | |
60 | } | |
61 | name = ttyname(*ttyfd); | |
62 | if (!name) | |
63 | fatal("openpty returns device for which ttyname fails."); | |
64 | ||
65 | strlcpy(namebuf, name, namebuflen); /* possible truncation */ | |
66 | return 1; | |
67 | #else /* HAVE_OPENPTY */ | |
68 | #ifdef HAVE__GETPTY | |
69 | /* | |
70 | * _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more | |
71 | * pty's automagically when needed | |
72 | */ | |
73 | char *slave; | |
74 | ||
75 | slave = _getpty(ptyfd, O_RDWR, 0622, 0); | |
76 | if (slave == NULL) { | |
77 | error("_getpty: %.100s", strerror(errno)); | |
78 | return 0; | |
79 | } | |
80 | strlcpy(namebuf, slave, namebuflen); | |
81 | /* Open the slave side. */ | |
82 | *ttyfd = open(namebuf, O_RDWR | O_NOCTTY); | |
83 | if (*ttyfd < 0) { | |
84 | error("%.200s: %.100s", namebuf, strerror(errno)); | |
85 | close(*ptyfd); | |
86 | return 0; | |
87 | } | |
88 | return 1; | |
89 | #else /* HAVE__GETPTY */ | |
90 | #if defined(HAVE_DEV_PTMX) | |
91 | /* | |
92 | * This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3 | |
93 | * also has bsd-style ptys, but they simply do not work.) | |
94 | */ | |
95 | int ptm; | |
96 | char *pts; | |
97 | mysig_t old_signal; | |
98 | ||
99 | ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY); | |
100 | if (ptm < 0) { | |
101 | error("/dev/ptmx: %.100s", strerror(errno)); | |
102 | return 0; | |
103 | } | |
104 | old_signal = mysignal(SIGCHLD, SIG_DFL); | |
105 | if (grantpt(ptm) < 0) { | |
106 | error("grantpt: %.100s", strerror(errno)); | |
107 | return 0; | |
108 | } | |
109 | mysignal(SIGCHLD, old_signal); | |
110 | if (unlockpt(ptm) < 0) { | |
111 | error("unlockpt: %.100s", strerror(errno)); | |
112 | return 0; | |
113 | } | |
114 | pts = ptsname(ptm); | |
115 | if (pts == NULL) | |
116 | error("Slave pty side name could not be obtained."); | |
117 | strlcpy(namebuf, pts, namebuflen); | |
118 | *ptyfd = ptm; | |
119 | ||
120 | /* Open the slave side. */ | |
121 | *ttyfd = open(namebuf, O_RDWR | O_NOCTTY); | |
122 | if (*ttyfd < 0) { | |
123 | error("%.100s: %.100s", namebuf, strerror(errno)); | |
124 | close(*ptyfd); | |
125 | return 0; | |
126 | } | |
127 | #ifndef HAVE_CYGWIN | |
128 | /* | |
129 | * Push the appropriate streams modules, as described in Solaris pts(7). | |
130 | * HP-UX pts(7) doesn't have ttcompat module. | |
131 | */ | |
132 | if (ioctl(*ttyfd, I_PUSH, "ptem") < 0) | |
133 | error("ioctl I_PUSH ptem: %.100s", strerror(errno)); | |
134 | if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0) | |
135 | error("ioctl I_PUSH ldterm: %.100s", strerror(errno)); | |
136 | #ifndef __hpux | |
137 | if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0) | |
138 | error("ioctl I_PUSH ttcompat: %.100s", strerror(errno)); | |
139 | #endif | |
140 | #endif | |
141 | return 1; | |
142 | #else /* HAVE_DEV_PTMX */ | |
143 | #ifdef HAVE_DEV_PTS_AND_PTC | |
144 | /* AIX-style pty code. */ | |
145 | const char *name; | |
146 | ||
147 | *ptyfd = open("/dev/ptc", O_RDWR | O_NOCTTY); | |
148 | if (*ptyfd < 0) { | |
149 | error("Could not open /dev/ptc: %.100s", strerror(errno)); | |
150 | return 0; | |
151 | } | |
152 | name = ttyname(*ptyfd); | |
153 | if (!name) | |
154 | fatal("Open of /dev/ptc returns device for which ttyname fails."); | |
155 | strlcpy(namebuf, name, namebuflen); | |
156 | *ttyfd = open(name, O_RDWR | O_NOCTTY); | |
157 | if (*ttyfd < 0) { | |
158 | error("Could not open pty slave side %.100s: %.100s", | |
159 | name, strerror(errno)); | |
160 | close(*ptyfd); | |
161 | return 0; | |
162 | } | |
163 | return 1; | |
164 | #else /* HAVE_DEV_PTS_AND_PTC */ | |
165 | #ifdef _CRAY | |
166 | char buf[64]; | |
167 | int i; | |
168 | int highpty; | |
169 | ||
170 | #ifdef _SC_CRAY_NPTY | |
171 | highpty = sysconf(_SC_CRAY_NPTY); | |
172 | if (highpty == -1) | |
173 | highpty = 128; | |
174 | #else | |
175 | highpty = 128; | |
176 | #endif | |
177 | ||
178 | for (i = 0; i < highpty; i++) { | |
179 | snprintf(buf, sizeof(buf), "/dev/pty/%03d", i); | |
180 | *ptyfd = open(buf, O_RDWR|O_NOCTTY); | |
181 | if (*ptyfd < 0) | |
182 | continue; | |
183 | snprintf(namebuf, namebuflen, "/dev/ttyp%03d", i); | |
184 | /* Open the slave side. */ | |
185 | *ttyfd = open(namebuf, O_RDWR|O_NOCTTY); | |
186 | if (*ttyfd < 0) { | |
187 | error("%.100s: %.100s", namebuf, strerror(errno)); | |
188 | close(*ptyfd); | |
189 | return 0; | |
190 | } | |
191 | return 1; | |
192 | } | |
193 | return 0; | |
194 | #else | |
195 | /* BSD-style pty code. */ | |
196 | char buf[64]; | |
197 | int i; | |
198 | const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ"; | |
199 | const char *ptyminors = "0123456789abcdef"; | |
200 | int num_minors = strlen(ptyminors); | |
201 | int num_ptys = strlen(ptymajors) * num_minors; | |
202 | ||
203 | for (i = 0; i < num_ptys; i++) { | |
204 | snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors], | |
205 | ptyminors[i % num_minors]); | |
206 | snprintf(namebuf, namebuflen, "/dev/tty%c%c", | |
207 | ptymajors[i / num_minors], ptyminors[i % num_minors]); | |
208 | ||
209 | *ptyfd = open(buf, O_RDWR | O_NOCTTY); | |
210 | if (*ptyfd < 0) { | |
211 | /* Try SCO style naming */ | |
212 | snprintf(buf, sizeof buf, "/dev/ptyp%d", i); | |
213 | snprintf(namebuf, namebuflen, "/dev/ttyp%d", i); | |
214 | *ptyfd = open(buf, O_RDWR | O_NOCTTY); | |
215 | if (*ptyfd < 0) | |
216 | continue; | |
217 | } | |
218 | ||
219 | /* Open the slave side. */ | |
220 | *ttyfd = open(namebuf, O_RDWR | O_NOCTTY); | |
221 | if (*ttyfd < 0) { | |
222 | error("%.100s: %.100s", namebuf, strerror(errno)); | |
223 | close(*ptyfd); | |
224 | return 0; | |
225 | } | |
226 | return 1; | |
227 | } | |
228 | return 0; | |
229 | #endif /* CRAY */ | |
230 | #endif /* HAVE_DEV_PTS_AND_PTC */ | |
231 | #endif /* HAVE_DEV_PTMX */ | |
232 | #endif /* HAVE__GETPTY */ | |
233 | #endif /* HAVE_OPENPTY */ | |
234 | } | |
235 | ||
236 | /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ | |
237 | ||
238 | void | |
239 | pty_release(const char *ttyname) | |
240 | { | |
241 | if (chown(ttyname, (uid_t) 0, (gid_t) 0) < 0) | |
242 | error("chown %.100s 0 0 failed: %.100s", ttyname, strerror(errno)); | |
243 | if (chmod(ttyname, (mode_t) 0666) < 0) | |
244 | error("chmod %.100s 0666 failed: %.100s", ttyname, strerror(errno)); | |
245 | } | |
246 | ||
247 | /* Makes the tty the processes controlling tty and sets it to sane modes. */ | |
248 | ||
249 | void | |
250 | pty_make_controlling_tty(int *ttyfd, const char *ttyname) | |
251 | { | |
252 | int fd; | |
253 | #ifdef USE_VHANGUP | |
254 | void *old; | |
255 | #endif /* USE_VHANGUP */ | |
256 | ||
257 | #ifdef _CRAY | |
258 | if (setsid() < 0) | |
259 | error("setsid: %.100s", strerror(errno)); | |
260 | ||
261 | fd = open(ttyname, O_RDWR|O_NOCTTY); | |
262 | if (fd != -1) { | |
263 | mysignal(SIGHUP, SIG_IGN); | |
264 | ioctl(fd, TCVHUP, (char *)NULL); | |
265 | mysignal(SIGHUP, SIG_DFL); | |
266 | setpgid(0, 0); | |
267 | close(fd); | |
268 | } else { | |
269 | error("Failed to disconnect from controlling tty."); | |
270 | } | |
271 | ||
272 | debug("Setting controlling tty using TCSETCTTY."); | |
273 | ioctl(*ttyfd, TCSETCTTY, NULL); | |
274 | fd = open("/dev/tty", O_RDWR); | |
275 | if (fd < 0) | |
276 | error("%.100s: %.100s", ttyname, strerror(errno)); | |
277 | close(*ttyfd); | |
278 | *ttyfd = fd; | |
279 | #else /* _CRAY */ | |
280 | ||
281 | /* First disconnect from the old controlling tty. */ | |
282 | #ifdef TIOCNOTTY | |
283 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
284 | if (fd >= 0) { | |
285 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
286 | close(fd); | |
287 | } | |
288 | #endif /* TIOCNOTTY */ | |
289 | if (setsid() < 0) | |
290 | error("setsid: %.100s", strerror(errno)); | |
291 | ||
292 | /* | |
293 | * Verify that we are successfully disconnected from the controlling | |
294 | * tty. | |
295 | */ | |
296 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
297 | if (fd >= 0) { | |
298 | error("Failed to disconnect from controlling tty."); | |
299 | close(fd); | |
300 | } | |
301 | /* Make it our controlling tty. */ | |
302 | #ifdef TIOCSCTTY | |
303 | debug("Setting controlling tty using TIOCSCTTY."); | |
304 | if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) | |
305 | error("ioctl(TIOCSCTTY): %.100s", strerror(errno)); | |
306 | #endif /* TIOCSCTTY */ | |
307 | #ifdef HAVE_NEWS4 | |
308 | if (setpgrp(0,0) < 0) | |
309 | error("SETPGRP %s",strerror(errno)); | |
310 | #endif /* HAVE_NEWS4 */ | |
311 | #ifdef USE_VHANGUP | |
312 | old = mysignal(SIGHUP, SIG_IGN); | |
313 | vhangup(); | |
314 | mysignal(SIGHUP, old); | |
315 | #endif /* USE_VHANGUP */ | |
316 | fd = open(ttyname, O_RDWR); | |
317 | if (fd < 0) { | |
318 | error("%.100s: %.100s", ttyname, strerror(errno)); | |
319 | } else { | |
320 | #ifdef USE_VHANGUP | |
321 | close(*ttyfd); | |
322 | *ttyfd = fd; | |
323 | #else /* USE_VHANGUP */ | |
324 | close(fd); | |
325 | #endif /* USE_VHANGUP */ | |
326 | } | |
327 | /* Verify that we now have a controlling tty. */ | |
328 | fd = open(_PATH_TTY, O_WRONLY); | |
329 | if (fd < 0) | |
330 | error("open /dev/tty failed - could not set controlling tty: %.100s", | |
331 | strerror(errno)); | |
332 | else { | |
333 | close(fd); | |
334 | } | |
335 | #endif /* _CRAY */ | |
336 | } | |
337 | ||
338 | /* Changes the window size associated with the pty. */ | |
339 | ||
340 | void | |
341 | pty_change_window_size(int ptyfd, int row, int col, | |
342 | int xpixel, int ypixel) | |
343 | { | |
344 | struct winsize w; | |
345 | w.ws_row = row; | |
346 | w.ws_col = col; | |
347 | w.ws_xpixel = xpixel; | |
348 | w.ws_ypixel = ypixel; | |
349 | (void) ioctl(ptyfd, TIOCSWINSZ, &w); | |
350 | } | |
351 | ||
352 | void | |
353 | pty_setowner(struct passwd *pw, const char *ttyname) | |
354 | { | |
355 | struct group *grp; | |
356 | gid_t gid; | |
357 | mode_t mode; | |
358 | struct stat st; | |
359 | ||
360 | /* Determine the group to make the owner of the tty. */ | |
361 | grp = getgrnam("tty"); | |
362 | if (grp) { | |
363 | gid = grp->gr_gid; | |
364 | mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
365 | } else { | |
366 | gid = pw->pw_gid; | |
367 | mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
368 | } | |
369 | ||
370 | /* | |
371 | * Change owner and mode of the tty as required. | |
372 | * Warn but continue if filesystem is read-only and the uids match/ | |
373 | * tty is owned by root. | |
374 | */ | |
375 | if (stat(ttyname, &st)) | |
376 | fatal("stat(%.100s) failed: %.100s", ttyname, | |
377 | strerror(errno)); | |
378 | ||
379 | if (st.st_uid != pw->pw_uid || st.st_gid != gid) { | |
380 | if (chown(ttyname, pw->pw_uid, gid) < 0) { | |
381 | if (errno == EROFS && | |
382 | (st.st_uid == pw->pw_uid || st.st_uid == 0)) | |
383 | error("chown(%.100s, %d, %d) failed: %.100s", | |
384 | ttyname, pw->pw_uid, gid, | |
385 | strerror(errno)); | |
386 | else | |
387 | fatal("chown(%.100s, %d, %d) failed: %.100s", | |
388 | ttyname, pw->pw_uid, gid, | |
389 | strerror(errno)); | |
390 | } | |
391 | } | |
392 | ||
393 | if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { | |
394 | if (chmod(ttyname, mode) < 0) { | |
395 | if (errno == EROFS && | |
396 | (st.st_mode & (S_IRGRP | S_IROTH)) == 0) | |
397 | error("chmod(%.100s, 0%o) failed: %.100s", | |
398 | ttyname, mode, strerror(errno)); | |
399 | else | |
400 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
401 | ttyname, mode, strerror(errno)); | |
402 | } | |
403 | } | |
404 | } |