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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" | |
1d3e026f | 15 | RCSID("$OpenBSD: sshpty.c,v 1.13 2006/02/07 01:42:00 stevesk Exp $"); |
16 | ||
17 | #include <termios.h> | |
8efc0c15 | 18 | |
884bcb37 | 19 | #ifdef HAVE_UTIL_H |
20 | # include <util.h> | |
21 | #endif /* HAVE_UTIL_H */ | |
22 | ||
1729c161 | 23 | #include "sshpty.h" |
42f11eb2 | 24 | #include "log.h" |
5ad9f968 | 25 | #include "misc.h" |
5260325f | 26 | |
6d8c4ea4 | 27 | #ifdef HAVE_PTY_H |
28 | # include <pty.h> | |
29 | #endif | |
6d8c4ea4 | 30 | |
8efc0c15 | 31 | #ifndef O_NOCTTY |
32 | #define O_NOCTTY 0 | |
33 | #endif | |
34 | ||
aa3378df | 35 | /* |
36 | * Allocates and opens a pty. Returns 0 if no pty could be allocated, or | |
37 | * nonzero if a pty was successfully allocated. On success, open file | |
38 | * descriptors for the pty and tty sides and the name of the tty side are | |
39 | * returned (the buffer must be able to hold at least 64 characters). | |
40 | */ | |
8efc0c15 | 41 | |
6ae2364d | 42 | int |
a408af76 | 43 | pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen) |
8efc0c15 | 44 | { |
5260325f | 45 | /* openpty(3) exists in OSF/1 and some other os'es */ |
b82f1310 | 46 | char *name; |
5260325f | 47 | int i; |
8efc0c15 | 48 | |
b82f1310 | 49 | i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); |
5260325f | 50 | if (i < 0) { |
51 | error("openpty: %.100s", strerror(errno)); | |
52 | return 0; | |
53 | } | |
b82f1310 | 54 | name = ttyname(*ttyfd); |
55 | if (!name) | |
56 | fatal("openpty returns device for which ttyname fails."); | |
57 | ||
58 | strlcpy(namebuf, name, namebuflen); /* possible truncation */ | |
5260325f | 59 | return 1; |
8efc0c15 | 60 | } |
61 | ||
5260325f | 62 | /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ |
8efc0c15 | 63 | |
6ae2364d | 64 | void |
ca75d7de | 65 | pty_release(const char *tty) |
8efc0c15 | 66 | { |
ca75d7de | 67 | if (chown(tty, (uid_t) 0, (gid_t) 0) < 0) |
68 | error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno)); | |
69 | if (chmod(tty, (mode_t) 0666) < 0) | |
70 | error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno)); | |
8efc0c15 | 71 | } |
72 | ||
b8e04133 | 73 | /* Makes the tty the process's controlling tty and sets it to sane modes. */ |
8efc0c15 | 74 | |
6ae2364d | 75 | void |
ca75d7de | 76 | pty_make_controlling_tty(int *ttyfd, const char *tty) |
8efc0c15 | 77 | { |
1a23ac2c | 78 | int fd; |
8140f2aa | 79 | #ifdef USE_VHANGUP |
80 | void *old; | |
81 | #endif /* USE_VHANGUP */ | |
1a23ac2c | 82 | |
ef51930f | 83 | #ifdef _UNICOS |
68187931 | 84 | if (setsid() < 0) |
85 | error("setsid: %.100s", strerror(errno)); | |
1a23ac2c | 86 | |
ca75d7de | 87 | fd = open(tty, O_RDWR|O_NOCTTY); |
68187931 | 88 | if (fd != -1) { |
f00d1f78 | 89 | signal(SIGHUP, SIG_IGN); |
68187931 | 90 | ioctl(fd, TCVHUP, (char *)NULL); |
f00d1f78 | 91 | signal(SIGHUP, SIG_DFL); |
68187931 | 92 | setpgid(0, 0); |
93 | close(fd); | |
1a23ac2c | 94 | } else { |
68187931 | 95 | error("Failed to disconnect from controlling tty."); |
1a23ac2c | 96 | } |
1a23ac2c | 97 | |
68187931 | 98 | debug("Setting controlling tty using TCSETCTTY."); |
99 | ioctl(*ttyfd, TCSETCTTY, NULL); | |
100 | fd = open("/dev/tty", O_RDWR); | |
101 | if (fd < 0) | |
ca75d7de | 102 | error("%.100s: %.100s", tty, strerror(errno)); |
1a23ac2c | 103 | close(*ttyfd); |
875ec275 | 104 | *ttyfd = fd; |
ef51930f | 105 | #else /* _UNICOS */ |
8efc0c15 | 106 | |
5260325f | 107 | /* First disconnect from the old controlling tty. */ |
8efc0c15 | 108 | #ifdef TIOCNOTTY |
5ca51e19 | 109 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 110 | if (fd >= 0) { |
111 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
112 | close(fd); | |
113 | } | |
8efc0c15 | 114 | #endif /* TIOCNOTTY */ |
5260325f | 115 | if (setsid() < 0) |
116 | error("setsid: %.100s", strerror(errno)); | |
117 | ||
aa3378df | 118 | /* |
119 | * Verify that we are successfully disconnected from the controlling | |
120 | * tty. | |
121 | */ | |
5ca51e19 | 122 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 123 | if (fd >= 0) { |
124 | error("Failed to disconnect from controlling tty."); | |
125 | close(fd); | |
126 | } | |
127 | /* Make it our controlling tty. */ | |
8efc0c15 | 128 | #ifdef TIOCSCTTY |
5260325f | 129 | debug("Setting controlling tty using TIOCSCTTY."); |
a3bf38d0 | 130 | if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) |
131 | error("ioctl(TIOCSCTTY): %.100s", strerror(errno)); | |
8efc0c15 | 132 | #endif /* TIOCSCTTY */ |
35fc74ed | 133 | #ifdef NEED_SETPGRP |
66d6c27e | 134 | if (setpgrp(0,0) < 0) |
135 | error("SETPGRP %s",strerror(errno)); | |
35fc74ed | 136 | #endif /* NEED_SETPGRP */ |
3c62e7eb | 137 | #ifdef USE_VHANGUP |
f00d1f78 | 138 | old = signal(SIGHUP, SIG_IGN); |
4e577b89 | 139 | vhangup(); |
f00d1f78 | 140 | signal(SIGHUP, old); |
3c62e7eb | 141 | #endif /* USE_VHANGUP */ |
ca75d7de | 142 | fd = open(tty, O_RDWR); |
4e577b89 | 143 | if (fd < 0) { |
ca75d7de | 144 | error("%.100s: %.100s", tty, strerror(errno)); |
4e577b89 | 145 | } else { |
3c62e7eb | 146 | #ifdef USE_VHANGUP |
4e577b89 | 147 | close(*ttyfd); |
148 | *ttyfd = fd; | |
3c62e7eb | 149 | #else /* USE_VHANGUP */ |
5260325f | 150 | close(fd); |
3c62e7eb | 151 | #endif /* USE_VHANGUP */ |
4e577b89 | 152 | } |
5260325f | 153 | /* Verify that we now have a controlling tty. */ |
5ca51e19 | 154 | fd = open(_PATH_TTY, O_WRONLY); |
5260325f | 155 | if (fd < 0) |
156 | error("open /dev/tty failed - could not set controlling tty: %.100s", | |
184eed6a | 157 | strerror(errno)); |
aff51935 | 158 | else |
5260325f | 159 | close(fd); |
ef51930f | 160 | #endif /* _UNICOS */ |
8efc0c15 | 161 | } |
162 | ||
163 | /* Changes the window size associated with the pty. */ | |
164 | ||
6ae2364d | 165 | void |
5260325f | 166 | pty_change_window_size(int ptyfd, int row, int col, |
184eed6a | 167 | int xpixel, int ypixel) |
8efc0c15 | 168 | { |
5260325f | 169 | struct winsize w; |
f09ce20a | 170 | |
5260325f | 171 | w.ws_row = row; |
172 | w.ws_col = col; | |
173 | w.ws_xpixel = xpixel; | |
174 | w.ws_ypixel = ypixel; | |
175 | (void) ioctl(ptyfd, TIOCSWINSZ, &w); | |
8efc0c15 | 176 | } |
817175bc | 177 | |
178 | void | |
ca75d7de | 179 | pty_setowner(struct passwd *pw, const char *tty) |
817175bc | 180 | { |
181 | struct group *grp; | |
182 | gid_t gid; | |
183 | mode_t mode; | |
227e8e86 | 184 | struct stat st; |
817175bc | 185 | |
186 | /* Determine the group to make the owner of the tty. */ | |
187 | grp = getgrnam("tty"); | |
188 | if (grp) { | |
189 | gid = grp->gr_gid; | |
190 | mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
191 | } else { | |
192 | gid = pw->pw_gid; | |
193 | mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
194 | } | |
195 | ||
227e8e86 | 196 | /* |
197 | * Change owner and mode of the tty as required. | |
4f7893dc | 198 | * Warn but continue if filesystem is read-only and the uids match/ |
199 | * tty is owned by root. | |
227e8e86 | 200 | */ |
ca75d7de | 201 | if (stat(tty, &st)) |
202 | fatal("stat(%.100s) failed: %.100s", tty, | |
227e8e86 | 203 | strerror(errno)); |
204 | ||
205 | if (st.st_uid != pw->pw_uid || st.st_gid != gid) { | |
ca75d7de | 206 | if (chown(tty, pw->pw_uid, gid) < 0) { |
184eed6a | 207 | if (errno == EROFS && |
f09ce20a | 208 | (st.st_uid == pw->pw_uid || st.st_uid == 0)) |
d6dc3576 | 209 | debug("chown(%.100s, %u, %u) failed: %.100s", |
ca75d7de | 210 | tty, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 211 | strerror(errno)); |
227e8e86 | 212 | else |
d6133f43 | 213 | fatal("chown(%.100s, %u, %u) failed: %.100s", |
ca75d7de | 214 | tty, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 215 | strerror(errno)); |
227e8e86 | 216 | } |
217 | } | |
218 | ||
219 | if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { | |
ca75d7de | 220 | if (chmod(tty, mode) < 0) { |
227e8e86 | 221 | if (errno == EROFS && |
222 | (st.st_mode & (S_IRGRP | S_IROTH)) == 0) | |
d6dc3576 | 223 | debug("chmod(%.100s, 0%o) failed: %.100s", |
ca75d7de | 224 | tty, (u_int)mode, strerror(errno)); |
227e8e86 | 225 | else |
226 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
ca75d7de | 227 | tty, (u_int)mode, strerror(errno)); |
227e8e86 | 228 | } |
229 | } | |
817175bc | 230 | } |