]>
Commit | Line | Data |
---|---|---|
028094f4 | 1 | /* $OpenBSD: sshpty.c,v 1.23 2006/07/11 20:07:25 stevesk Exp $ */ |
8efc0c15 | 2 | /* |
5260325f | 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
5260325f | 4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
5 | * All rights reserved | |
5260325f | 6 | * Allocating a pseudo-terminal, and making it the controlling tty. |
6ae2364d | 7 | * |
bcbf86ec | 8 | * As far as I am concerned, the code I have written for this software |
9 | * can be used freely for any purpose. Any derived versions of this | |
10 | * software must be clearly marked as such, and if the derived work is | |
11 | * incompatible with the protocol description in the RFC file, it must be | |
12 | * called by a name other than "ssh" or "Secure Shell". | |
5260325f | 13 | */ |
8efc0c15 | 14 | |
15 | #include "includes.h" | |
bd7c69ea | 16 | |
17 | #include <sys/ioctl.h> | |
4095f623 | 18 | #include <sys/types.h> |
19 | #include <sys/stat.h> | |
3e9b2b1b | 20 | #include <signal.h> |
8efc0c15 | 21 | |
028094f4 | 22 | #include <errno.h> |
d3221cca | 23 | #include <fcntl.h> |
16fbe330 | 24 | #include <grp.h> |
a75f5360 | 25 | #ifdef HAVE_PATHS_H |
6f61e0ec | 26 | # include <paths.h> |
a75f5360 | 27 | #endif |
b1842393 | 28 | #include <pwd.h> |
a75f5360 | 29 | #include <termios.h> |
884bcb37 | 30 | #ifdef HAVE_UTIL_H |
31 | # include <util.h> | |
32 | #endif /* HAVE_UTIL_H */ | |
33 | ||
1729c161 | 34 | #include "sshpty.h" |
42f11eb2 | 35 | #include "log.h" |
5ad9f968 | 36 | #include "misc.h" |
5260325f | 37 | |
6d8c4ea4 | 38 | #ifdef HAVE_PTY_H |
39 | # include <pty.h> | |
40 | #endif | |
6d8c4ea4 | 41 | |
8efc0c15 | 42 | #ifndef O_NOCTTY |
43 | #define O_NOCTTY 0 | |
44 | #endif | |
45 | ||
aa3378df | 46 | /* |
47 | * Allocates and opens a pty. Returns 0 if no pty could be allocated, or | |
48 | * nonzero if a pty was successfully allocated. On success, open file | |
49 | * descriptors for the pty and tty sides and the name of the tty side are | |
50 | * returned (the buffer must be able to hold at least 64 characters). | |
51 | */ | |
8efc0c15 | 52 | |
6ae2364d | 53 | int |
148de80c | 54 | pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen) |
8efc0c15 | 55 | { |
5260325f | 56 | /* openpty(3) exists in OSF/1 and some other os'es */ |
b82f1310 | 57 | char *name; |
5260325f | 58 | int i; |
8efc0c15 | 59 | |
b82f1310 | 60 | i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); |
5260325f | 61 | if (i < 0) { |
62 | error("openpty: %.100s", strerror(errno)); | |
63 | return 0; | |
64 | } | |
b82f1310 | 65 | name = ttyname(*ttyfd); |
66 | if (!name) | |
67 | fatal("openpty returns device for which ttyname fails."); | |
68 | ||
69 | strlcpy(namebuf, name, namebuflen); /* possible truncation */ | |
5260325f | 70 | return 1; |
8efc0c15 | 71 | } |
72 | ||
5260325f | 73 | /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ |
8efc0c15 | 74 | |
6ae2364d | 75 | void |
ca75d7de | 76 | pty_release(const char *tty) |
8efc0c15 | 77 | { |
ca75d7de | 78 | if (chown(tty, (uid_t) 0, (gid_t) 0) < 0) |
79 | error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno)); | |
80 | if (chmod(tty, (mode_t) 0666) < 0) | |
81 | error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno)); | |
8efc0c15 | 82 | } |
83 | ||
b8e04133 | 84 | /* Makes the tty the process's controlling tty and sets it to sane modes. */ |
8efc0c15 | 85 | |
6ae2364d | 86 | void |
ca75d7de | 87 | pty_make_controlling_tty(int *ttyfd, const char *tty) |
8efc0c15 | 88 | { |
1a23ac2c | 89 | int fd; |
8140f2aa | 90 | #ifdef USE_VHANGUP |
91 | void *old; | |
92 | #endif /* USE_VHANGUP */ | |
1a23ac2c | 93 | |
ef51930f | 94 | #ifdef _UNICOS |
68187931 | 95 | if (setsid() < 0) |
96 | error("setsid: %.100s", strerror(errno)); | |
1a23ac2c | 97 | |
ca75d7de | 98 | fd = open(tty, O_RDWR|O_NOCTTY); |
68187931 | 99 | if (fd != -1) { |
f00d1f78 | 100 | signal(SIGHUP, SIG_IGN); |
68187931 | 101 | ioctl(fd, TCVHUP, (char *)NULL); |
f00d1f78 | 102 | signal(SIGHUP, SIG_DFL); |
68187931 | 103 | setpgid(0, 0); |
104 | close(fd); | |
1a23ac2c | 105 | } else { |
68187931 | 106 | error("Failed to disconnect from controlling tty."); |
1a23ac2c | 107 | } |
1a23ac2c | 108 | |
68187931 | 109 | debug("Setting controlling tty using TCSETCTTY."); |
110 | ioctl(*ttyfd, TCSETCTTY, NULL); | |
111 | fd = open("/dev/tty", O_RDWR); | |
112 | if (fd < 0) | |
ca75d7de | 113 | error("%.100s: %.100s", tty, strerror(errno)); |
1a23ac2c | 114 | close(*ttyfd); |
875ec275 | 115 | *ttyfd = fd; |
ef51930f | 116 | #else /* _UNICOS */ |
8efc0c15 | 117 | |
5260325f | 118 | /* First disconnect from the old controlling tty. */ |
8efc0c15 | 119 | #ifdef TIOCNOTTY |
5ca51e19 | 120 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 121 | if (fd >= 0) { |
122 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
123 | close(fd); | |
124 | } | |
8efc0c15 | 125 | #endif /* TIOCNOTTY */ |
5260325f | 126 | if (setsid() < 0) |
127 | error("setsid: %.100s", strerror(errno)); | |
128 | ||
aa3378df | 129 | /* |
130 | * Verify that we are successfully disconnected from the controlling | |
131 | * tty. | |
132 | */ | |
5ca51e19 | 133 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 134 | if (fd >= 0) { |
135 | error("Failed to disconnect from controlling tty."); | |
136 | close(fd); | |
137 | } | |
138 | /* Make it our controlling tty. */ | |
8efc0c15 | 139 | #ifdef TIOCSCTTY |
5260325f | 140 | debug("Setting controlling tty using TIOCSCTTY."); |
a3bf38d0 | 141 | if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) |
142 | error("ioctl(TIOCSCTTY): %.100s", strerror(errno)); | |
8efc0c15 | 143 | #endif /* TIOCSCTTY */ |
35fc74ed | 144 | #ifdef NEED_SETPGRP |
66d6c27e | 145 | if (setpgrp(0,0) < 0) |
146 | error("SETPGRP %s",strerror(errno)); | |
35fc74ed | 147 | #endif /* NEED_SETPGRP */ |
3c62e7eb | 148 | #ifdef USE_VHANGUP |
f00d1f78 | 149 | old = signal(SIGHUP, SIG_IGN); |
4e577b89 | 150 | vhangup(); |
f00d1f78 | 151 | signal(SIGHUP, old); |
3c62e7eb | 152 | #endif /* USE_VHANGUP */ |
ca75d7de | 153 | fd = open(tty, O_RDWR); |
4e577b89 | 154 | if (fd < 0) { |
ca75d7de | 155 | error("%.100s: %.100s", tty, strerror(errno)); |
4e577b89 | 156 | } else { |
3c62e7eb | 157 | #ifdef USE_VHANGUP |
4e577b89 | 158 | close(*ttyfd); |
159 | *ttyfd = fd; | |
3c62e7eb | 160 | #else /* USE_VHANGUP */ |
5260325f | 161 | close(fd); |
3c62e7eb | 162 | #endif /* USE_VHANGUP */ |
4e577b89 | 163 | } |
5260325f | 164 | /* Verify that we now have a controlling tty. */ |
5ca51e19 | 165 | fd = open(_PATH_TTY, O_WRONLY); |
5260325f | 166 | if (fd < 0) |
167 | error("open /dev/tty failed - could not set controlling tty: %.100s", | |
184eed6a | 168 | strerror(errno)); |
aff51935 | 169 | else |
5260325f | 170 | close(fd); |
ef51930f | 171 | #endif /* _UNICOS */ |
8efc0c15 | 172 | } |
173 | ||
174 | /* Changes the window size associated with the pty. */ | |
175 | ||
6ae2364d | 176 | void |
148de80c | 177 | pty_change_window_size(int ptyfd, u_int row, u_int col, |
178 | u_int xpixel, u_int ypixel) | |
8efc0c15 | 179 | { |
5260325f | 180 | struct winsize w; |
f09ce20a | 181 | |
148de80c | 182 | /* may truncate u_int -> u_short */ |
5260325f | 183 | w.ws_row = row; |
184 | w.ws_col = col; | |
185 | w.ws_xpixel = xpixel; | |
186 | w.ws_ypixel = ypixel; | |
187 | (void) ioctl(ptyfd, TIOCSWINSZ, &w); | |
8efc0c15 | 188 | } |
817175bc | 189 | |
190 | void | |
ca75d7de | 191 | pty_setowner(struct passwd *pw, const char *tty) |
817175bc | 192 | { |
193 | struct group *grp; | |
194 | gid_t gid; | |
195 | mode_t mode; | |
227e8e86 | 196 | struct stat st; |
817175bc | 197 | |
198 | /* Determine the group to make the owner of the tty. */ | |
199 | grp = getgrnam("tty"); | |
200 | if (grp) { | |
201 | gid = grp->gr_gid; | |
202 | mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
203 | } else { | |
204 | gid = pw->pw_gid; | |
205 | mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
206 | } | |
207 | ||
227e8e86 | 208 | /* |
209 | * Change owner and mode of the tty as required. | |
4f7893dc | 210 | * Warn but continue if filesystem is read-only and the uids match/ |
211 | * tty is owned by root. | |
227e8e86 | 212 | */ |
ca75d7de | 213 | if (stat(tty, &st)) |
214 | fatal("stat(%.100s) failed: %.100s", tty, | |
227e8e86 | 215 | strerror(errno)); |
216 | ||
ef4d1846 | 217 | #ifdef WITH_SELINUX |
218 | ssh_selinux_setup_pty(pw->pw_name, tty); | |
219 | #endif | |
220 | ||
227e8e86 | 221 | if (st.st_uid != pw->pw_uid || st.st_gid != gid) { |
ca75d7de | 222 | if (chown(tty, pw->pw_uid, gid) < 0) { |
184eed6a | 223 | if (errno == EROFS && |
f09ce20a | 224 | (st.st_uid == pw->pw_uid || st.st_uid == 0)) |
d6dc3576 | 225 | debug("chown(%.100s, %u, %u) failed: %.100s", |
ca75d7de | 226 | tty, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 227 | strerror(errno)); |
227e8e86 | 228 | else |
d6133f43 | 229 | fatal("chown(%.100s, %u, %u) failed: %.100s", |
ca75d7de | 230 | tty, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 231 | strerror(errno)); |
227e8e86 | 232 | } |
233 | } | |
234 | ||
235 | if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { | |
ca75d7de | 236 | if (chmod(tty, mode) < 0) { |
227e8e86 | 237 | if (errno == EROFS && |
238 | (st.st_mode & (S_IRGRP | S_IROTH)) == 0) | |
d6dc3576 | 239 | debug("chmod(%.100s, 0%o) failed: %.100s", |
ca75d7de | 240 | tty, (u_int)mode, strerror(errno)); |
227e8e86 | 241 | else |
242 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
ca75d7de | 243 | tty, (u_int)mode, strerror(errno)); |
227e8e86 | 244 | } |
245 | } | |
817175bc | 246 | } |