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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
5260325f | 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
4 | * All rights reserved | |
5260325f | 5 | * Allocating a pseudo-terminal, and making it the controlling tty. |
6ae2364d | 6 | * |
bcbf86ec | 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". | |
5260325f | 12 | */ |
8efc0c15 | 13 | |
14 | #include "includes.h" | |
a4de1163 | 15 | RCSID("$OpenBSD: sshpty.c,v 1.11 2004/01/11 21:55:06 deraadt Exp $"); |
8efc0c15 | 16 | |
884bcb37 | 17 | #ifdef HAVE_UTIL_H |
18 | # include <util.h> | |
19 | #endif /* HAVE_UTIL_H */ | |
20 | ||
1729c161 | 21 | #include "sshpty.h" |
42f11eb2 | 22 | #include "log.h" |
5ad9f968 | 23 | #include "misc.h" |
5260325f | 24 | |
6d8c4ea4 | 25 | #ifdef HAVE_PTY_H |
26 | # include <pty.h> | |
27 | #endif | |
6d8c4ea4 | 28 | |
8efc0c15 | 29 | #ifndef O_NOCTTY |
30 | #define O_NOCTTY 0 | |
31 | #endif | |
32 | ||
aa3378df | 33 | /* |
34 | * Allocates and opens a pty. Returns 0 if no pty could be allocated, or | |
35 | * nonzero if a pty was successfully allocated. On success, open file | |
36 | * descriptors for the pty and tty sides and the name of the tty side are | |
37 | * returned (the buffer must be able to hold at least 64 characters). | |
38 | */ | |
8efc0c15 | 39 | |
6ae2364d | 40 | int |
a408af76 | 41 | pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen) |
8efc0c15 | 42 | { |
5260325f | 43 | /* openpty(3) exists in OSF/1 and some other os'es */ |
b82f1310 | 44 | char *name; |
5260325f | 45 | int i; |
8efc0c15 | 46 | |
b82f1310 | 47 | i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); |
5260325f | 48 | if (i < 0) { |
49 | error("openpty: %.100s", strerror(errno)); | |
50 | return 0; | |
51 | } | |
b82f1310 | 52 | name = ttyname(*ttyfd); |
53 | if (!name) | |
54 | fatal("openpty returns device for which ttyname fails."); | |
55 | ||
56 | strlcpy(namebuf, name, namebuflen); /* possible truncation */ | |
5260325f | 57 | return 1; |
8efc0c15 | 58 | } |
59 | ||
5260325f | 60 | /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ |
8efc0c15 | 61 | |
6ae2364d | 62 | void |
5260325f | 63 | pty_release(const char *ttyname) |
8efc0c15 | 64 | { |
3276571c | 65 | if (chown(ttyname, (uid_t) 0, (gid_t) 0) < 0) |
817175bc | 66 | error("chown %.100s 0 0 failed: %.100s", ttyname, strerror(errno)); |
3276571c | 67 | if (chmod(ttyname, (mode_t) 0666) < 0) |
817175bc | 68 | error("chmod %.100s 0666 failed: %.100s", ttyname, strerror(errno)); |
8efc0c15 | 69 | } |
70 | ||
b8e04133 | 71 | /* Makes the tty the process's controlling tty and sets it to sane modes. */ |
8efc0c15 | 72 | |
6ae2364d | 73 | void |
5260325f | 74 | pty_make_controlling_tty(int *ttyfd, const char *ttyname) |
8efc0c15 | 75 | { |
1a23ac2c | 76 | int fd; |
8140f2aa | 77 | #ifdef USE_VHANGUP |
78 | void *old; | |
79 | #endif /* USE_VHANGUP */ | |
1a23ac2c | 80 | |
ef51930f | 81 | #ifdef _UNICOS |
68187931 | 82 | if (setsid() < 0) |
83 | error("setsid: %.100s", strerror(errno)); | |
1a23ac2c | 84 | |
68187931 | 85 | fd = open(ttyname, O_RDWR|O_NOCTTY); |
86 | if (fd != -1) { | |
f00d1f78 | 87 | signal(SIGHUP, SIG_IGN); |
68187931 | 88 | ioctl(fd, TCVHUP, (char *)NULL); |
f00d1f78 | 89 | signal(SIGHUP, SIG_DFL); |
68187931 | 90 | setpgid(0, 0); |
91 | close(fd); | |
1a23ac2c | 92 | } else { |
68187931 | 93 | error("Failed to disconnect from controlling tty."); |
1a23ac2c | 94 | } |
1a23ac2c | 95 | |
68187931 | 96 | debug("Setting controlling tty using TCSETCTTY."); |
97 | ioctl(*ttyfd, TCSETCTTY, NULL); | |
98 | fd = open("/dev/tty", O_RDWR); | |
99 | if (fd < 0) | |
100 | error("%.100s: %.100s", ttyname, strerror(errno)); | |
1a23ac2c | 101 | close(*ttyfd); |
875ec275 | 102 | *ttyfd = fd; |
ef51930f | 103 | #else /* _UNICOS */ |
8efc0c15 | 104 | |
5260325f | 105 | /* First disconnect from the old controlling tty. */ |
8efc0c15 | 106 | #ifdef TIOCNOTTY |
5ca51e19 | 107 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 108 | if (fd >= 0) { |
109 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
110 | close(fd); | |
111 | } | |
8efc0c15 | 112 | #endif /* TIOCNOTTY */ |
5260325f | 113 | if (setsid() < 0) |
114 | error("setsid: %.100s", strerror(errno)); | |
115 | ||
aa3378df | 116 | /* |
117 | * Verify that we are successfully disconnected from the controlling | |
118 | * tty. | |
119 | */ | |
5ca51e19 | 120 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 121 | if (fd >= 0) { |
122 | error("Failed to disconnect from controlling tty."); | |
123 | close(fd); | |
124 | } | |
125 | /* Make it our controlling tty. */ | |
8efc0c15 | 126 | #ifdef TIOCSCTTY |
5260325f | 127 | debug("Setting controlling tty using TIOCSCTTY."); |
a3bf38d0 | 128 | if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) |
129 | error("ioctl(TIOCSCTTY): %.100s", strerror(errno)); | |
8efc0c15 | 130 | #endif /* TIOCSCTTY */ |
66d6c27e | 131 | #ifdef HAVE_NEWS4 |
132 | if (setpgrp(0,0) < 0) | |
133 | error("SETPGRP %s",strerror(errno)); | |
134 | #endif /* HAVE_NEWS4 */ | |
3c62e7eb | 135 | #ifdef USE_VHANGUP |
f00d1f78 | 136 | old = signal(SIGHUP, SIG_IGN); |
4e577b89 | 137 | vhangup(); |
f00d1f78 | 138 | signal(SIGHUP, old); |
3c62e7eb | 139 | #endif /* USE_VHANGUP */ |
5260325f | 140 | fd = open(ttyname, O_RDWR); |
4e577b89 | 141 | if (fd < 0) { |
5260325f | 142 | error("%.100s: %.100s", ttyname, strerror(errno)); |
4e577b89 | 143 | } else { |
3c62e7eb | 144 | #ifdef USE_VHANGUP |
4e577b89 | 145 | close(*ttyfd); |
146 | *ttyfd = fd; | |
3c62e7eb | 147 | #else /* USE_VHANGUP */ |
5260325f | 148 | close(fd); |
3c62e7eb | 149 | #endif /* USE_VHANGUP */ |
4e577b89 | 150 | } |
5260325f | 151 | /* Verify that we now have a controlling tty. */ |
5ca51e19 | 152 | fd = open(_PATH_TTY, O_WRONLY); |
5260325f | 153 | if (fd < 0) |
154 | error("open /dev/tty failed - could not set controlling tty: %.100s", | |
184eed6a | 155 | strerror(errno)); |
aff51935 | 156 | else |
5260325f | 157 | close(fd); |
ef51930f | 158 | #endif /* _UNICOS */ |
8efc0c15 | 159 | } |
160 | ||
161 | /* Changes the window size associated with the pty. */ | |
162 | ||
6ae2364d | 163 | void |
5260325f | 164 | pty_change_window_size(int ptyfd, int row, int col, |
184eed6a | 165 | int xpixel, int ypixel) |
8efc0c15 | 166 | { |
5260325f | 167 | struct winsize w; |
f09ce20a | 168 | |
5260325f | 169 | w.ws_row = row; |
170 | w.ws_col = col; | |
171 | w.ws_xpixel = xpixel; | |
172 | w.ws_ypixel = ypixel; | |
173 | (void) ioctl(ptyfd, TIOCSWINSZ, &w); | |
8efc0c15 | 174 | } |
817175bc | 175 | |
176 | void | |
177 | pty_setowner(struct passwd *pw, const char *ttyname) | |
178 | { | |
179 | struct group *grp; | |
180 | gid_t gid; | |
181 | mode_t mode; | |
227e8e86 | 182 | struct stat st; |
817175bc | 183 | |
184 | /* Determine the group to make the owner of the tty. */ | |
185 | grp = getgrnam("tty"); | |
186 | if (grp) { | |
187 | gid = grp->gr_gid; | |
188 | mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
189 | } else { | |
190 | gid = pw->pw_gid; | |
191 | mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
192 | } | |
193 | ||
227e8e86 | 194 | /* |
195 | * Change owner and mode of the tty as required. | |
4f7893dc | 196 | * Warn but continue if filesystem is read-only and the uids match/ |
197 | * tty is owned by root. | |
227e8e86 | 198 | */ |
199 | if (stat(ttyname, &st)) | |
200 | fatal("stat(%.100s) failed: %.100s", ttyname, | |
201 | strerror(errno)); | |
202 | ||
203 | if (st.st_uid != pw->pw_uid || st.st_gid != gid) { | |
204 | if (chown(ttyname, pw->pw_uid, gid) < 0) { | |
184eed6a | 205 | if (errno == EROFS && |
f09ce20a | 206 | (st.st_uid == pw->pw_uid || st.st_uid == 0)) |
d6dc3576 | 207 | debug("chown(%.100s, %u, %u) failed: %.100s", |
d0a1c5d1 | 208 | ttyname, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 209 | strerror(errno)); |
227e8e86 | 210 | else |
d6133f43 | 211 | fatal("chown(%.100s, %u, %u) failed: %.100s", |
d0a1c5d1 | 212 | ttyname, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 213 | strerror(errno)); |
227e8e86 | 214 | } |
215 | } | |
216 | ||
217 | if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { | |
218 | if (chmod(ttyname, mode) < 0) { | |
219 | if (errno == EROFS && | |
220 | (st.st_mode & (S_IRGRP | S_IROTH)) == 0) | |
d6dc3576 | 221 | debug("chmod(%.100s, 0%o) failed: %.100s", |
b9ed513a | 222 | ttyname, (u_int)mode, strerror(errno)); |
227e8e86 | 223 | else |
224 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
b9ed513a | 225 | ttyname, (u_int)mode, strerror(errno)); |
227e8e86 | 226 | } |
227 | } | |
817175bc | 228 | } |