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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" | |
bd7c69ea | 15 | |
16 | #include <sys/ioctl.h> | |
4095f623 | 17 | #include <sys/types.h> |
18 | #include <sys/stat.h> | |
3e9b2b1b | 19 | #include <signal.h> |
8efc0c15 | 20 | |
a75f5360 | 21 | #ifdef HAVE_PATHS_H |
6f61e0ec | 22 | # include <paths.h> |
a75f5360 | 23 | #endif |
24 | #include <termios.h> | |
884bcb37 | 25 | #ifdef HAVE_UTIL_H |
26 | # include <util.h> | |
27 | #endif /* HAVE_UTIL_H */ | |
28 | ||
1729c161 | 29 | #include "sshpty.h" |
42f11eb2 | 30 | #include "log.h" |
5ad9f968 | 31 | #include "misc.h" |
5260325f | 32 | |
6d8c4ea4 | 33 | #ifdef HAVE_PTY_H |
34 | # include <pty.h> | |
35 | #endif | |
6d8c4ea4 | 36 | |
8efc0c15 | 37 | #ifndef O_NOCTTY |
38 | #define O_NOCTTY 0 | |
39 | #endif | |
40 | ||
aa3378df | 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 | */ | |
8efc0c15 | 47 | |
6ae2364d | 48 | int |
148de80c | 49 | pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen) |
8efc0c15 | 50 | { |
5260325f | 51 | /* openpty(3) exists in OSF/1 and some other os'es */ |
b82f1310 | 52 | char *name; |
5260325f | 53 | int i; |
8efc0c15 | 54 | |
b82f1310 | 55 | i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); |
5260325f | 56 | if (i < 0) { |
57 | error("openpty: %.100s", strerror(errno)); | |
58 | return 0; | |
59 | } | |
b82f1310 | 60 | name = ttyname(*ttyfd); |
61 | if (!name) | |
62 | fatal("openpty returns device for which ttyname fails."); | |
63 | ||
64 | strlcpy(namebuf, name, namebuflen); /* possible truncation */ | |
5260325f | 65 | return 1; |
8efc0c15 | 66 | } |
67 | ||
5260325f | 68 | /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ |
8efc0c15 | 69 | |
6ae2364d | 70 | void |
ca75d7de | 71 | pty_release(const char *tty) |
8efc0c15 | 72 | { |
ca75d7de | 73 | if (chown(tty, (uid_t) 0, (gid_t) 0) < 0) |
74 | error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno)); | |
75 | if (chmod(tty, (mode_t) 0666) < 0) | |
76 | error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno)); | |
8efc0c15 | 77 | } |
78 | ||
b8e04133 | 79 | /* Makes the tty the process's controlling tty and sets it to sane modes. */ |
8efc0c15 | 80 | |
6ae2364d | 81 | void |
ca75d7de | 82 | pty_make_controlling_tty(int *ttyfd, const char *tty) |
8efc0c15 | 83 | { |
1a23ac2c | 84 | int fd; |
8140f2aa | 85 | #ifdef USE_VHANGUP |
86 | void *old; | |
87 | #endif /* USE_VHANGUP */ | |
1a23ac2c | 88 | |
ef51930f | 89 | #ifdef _UNICOS |
68187931 | 90 | if (setsid() < 0) |
91 | error("setsid: %.100s", strerror(errno)); | |
1a23ac2c | 92 | |
ca75d7de | 93 | fd = open(tty, O_RDWR|O_NOCTTY); |
68187931 | 94 | if (fd != -1) { |
f00d1f78 | 95 | signal(SIGHUP, SIG_IGN); |
68187931 | 96 | ioctl(fd, TCVHUP, (char *)NULL); |
f00d1f78 | 97 | signal(SIGHUP, SIG_DFL); |
68187931 | 98 | setpgid(0, 0); |
99 | close(fd); | |
1a23ac2c | 100 | } else { |
68187931 | 101 | error("Failed to disconnect from controlling tty."); |
1a23ac2c | 102 | } |
1a23ac2c | 103 | |
68187931 | 104 | debug("Setting controlling tty using TCSETCTTY."); |
105 | ioctl(*ttyfd, TCSETCTTY, NULL); | |
106 | fd = open("/dev/tty", O_RDWR); | |
107 | if (fd < 0) | |
ca75d7de | 108 | error("%.100s: %.100s", tty, strerror(errno)); |
1a23ac2c | 109 | close(*ttyfd); |
875ec275 | 110 | *ttyfd = fd; |
ef51930f | 111 | #else /* _UNICOS */ |
8efc0c15 | 112 | |
5260325f | 113 | /* First disconnect from the old controlling tty. */ |
8efc0c15 | 114 | #ifdef TIOCNOTTY |
5ca51e19 | 115 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 116 | if (fd >= 0) { |
117 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
118 | close(fd); | |
119 | } | |
8efc0c15 | 120 | #endif /* TIOCNOTTY */ |
5260325f | 121 | if (setsid() < 0) |
122 | error("setsid: %.100s", strerror(errno)); | |
123 | ||
aa3378df | 124 | /* |
125 | * Verify that we are successfully disconnected from the controlling | |
126 | * tty. | |
127 | */ | |
5ca51e19 | 128 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 129 | if (fd >= 0) { |
130 | error("Failed to disconnect from controlling tty."); | |
131 | close(fd); | |
132 | } | |
133 | /* Make it our controlling tty. */ | |
8efc0c15 | 134 | #ifdef TIOCSCTTY |
5260325f | 135 | debug("Setting controlling tty using TIOCSCTTY."); |
a3bf38d0 | 136 | if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) |
137 | error("ioctl(TIOCSCTTY): %.100s", strerror(errno)); | |
8efc0c15 | 138 | #endif /* TIOCSCTTY */ |
35fc74ed | 139 | #ifdef NEED_SETPGRP |
66d6c27e | 140 | if (setpgrp(0,0) < 0) |
141 | error("SETPGRP %s",strerror(errno)); | |
35fc74ed | 142 | #endif /* NEED_SETPGRP */ |
3c62e7eb | 143 | #ifdef USE_VHANGUP |
f00d1f78 | 144 | old = signal(SIGHUP, SIG_IGN); |
4e577b89 | 145 | vhangup(); |
f00d1f78 | 146 | signal(SIGHUP, old); |
3c62e7eb | 147 | #endif /* USE_VHANGUP */ |
ca75d7de | 148 | fd = open(tty, O_RDWR); |
4e577b89 | 149 | if (fd < 0) { |
ca75d7de | 150 | error("%.100s: %.100s", tty, strerror(errno)); |
4e577b89 | 151 | } else { |
3c62e7eb | 152 | #ifdef USE_VHANGUP |
4e577b89 | 153 | close(*ttyfd); |
154 | *ttyfd = fd; | |
3c62e7eb | 155 | #else /* USE_VHANGUP */ |
5260325f | 156 | close(fd); |
3c62e7eb | 157 | #endif /* USE_VHANGUP */ |
4e577b89 | 158 | } |
5260325f | 159 | /* Verify that we now have a controlling tty. */ |
5ca51e19 | 160 | fd = open(_PATH_TTY, O_WRONLY); |
5260325f | 161 | if (fd < 0) |
162 | error("open /dev/tty failed - could not set controlling tty: %.100s", | |
184eed6a | 163 | strerror(errno)); |
aff51935 | 164 | else |
5260325f | 165 | close(fd); |
ef51930f | 166 | #endif /* _UNICOS */ |
8efc0c15 | 167 | } |
168 | ||
169 | /* Changes the window size associated with the pty. */ | |
170 | ||
6ae2364d | 171 | void |
148de80c | 172 | pty_change_window_size(int ptyfd, u_int row, u_int col, |
173 | u_int xpixel, u_int ypixel) | |
8efc0c15 | 174 | { |
5260325f | 175 | struct winsize w; |
f09ce20a | 176 | |
148de80c | 177 | /* may truncate u_int -> u_short */ |
5260325f | 178 | w.ws_row = row; |
179 | w.ws_col = col; | |
180 | w.ws_xpixel = xpixel; | |
181 | w.ws_ypixel = ypixel; | |
182 | (void) ioctl(ptyfd, TIOCSWINSZ, &w); | |
8efc0c15 | 183 | } |
817175bc | 184 | |
185 | void | |
ca75d7de | 186 | pty_setowner(struct passwd *pw, const char *tty) |
817175bc | 187 | { |
188 | struct group *grp; | |
189 | gid_t gid; | |
190 | mode_t mode; | |
227e8e86 | 191 | struct stat st; |
817175bc | 192 | |
193 | /* Determine the group to make the owner of the tty. */ | |
194 | grp = getgrnam("tty"); | |
195 | if (grp) { | |
196 | gid = grp->gr_gid; | |
197 | mode = S_IRUSR | S_IWUSR | S_IWGRP; | |
198 | } else { | |
199 | gid = pw->pw_gid; | |
200 | mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; | |
201 | } | |
202 | ||
227e8e86 | 203 | /* |
204 | * Change owner and mode of the tty as required. | |
4f7893dc | 205 | * Warn but continue if filesystem is read-only and the uids match/ |
206 | * tty is owned by root. | |
227e8e86 | 207 | */ |
ca75d7de | 208 | if (stat(tty, &st)) |
209 | fatal("stat(%.100s) failed: %.100s", tty, | |
227e8e86 | 210 | strerror(errno)); |
211 | ||
212 | if (st.st_uid != pw->pw_uid || st.st_gid != gid) { | |
ca75d7de | 213 | if (chown(tty, pw->pw_uid, gid) < 0) { |
184eed6a | 214 | if (errno == EROFS && |
f09ce20a | 215 | (st.st_uid == pw->pw_uid || st.st_uid == 0)) |
d6dc3576 | 216 | debug("chown(%.100s, %u, %u) failed: %.100s", |
ca75d7de | 217 | tty, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 218 | strerror(errno)); |
227e8e86 | 219 | else |
d6133f43 | 220 | fatal("chown(%.100s, %u, %u) failed: %.100s", |
ca75d7de | 221 | tty, (u_int)pw->pw_uid, (u_int)gid, |
184eed6a | 222 | strerror(errno)); |
227e8e86 | 223 | } |
224 | } | |
225 | ||
226 | if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { | |
ca75d7de | 227 | if (chmod(tty, mode) < 0) { |
227e8e86 | 228 | if (errno == EROFS && |
229 | (st.st_mode & (S_IRGRP | S_IROTH)) == 0) | |
d6dc3576 | 230 | debug("chmod(%.100s, 0%o) failed: %.100s", |
ca75d7de | 231 | tty, (u_int)mode, strerror(errno)); |
227e8e86 | 232 | else |
233 | fatal("chmod(%.100s, 0%o) failed: %.100s", | |
ca75d7de | 234 | tty, (u_int)mode, strerror(errno)); |
227e8e86 | 235 | } |
236 | } | |
817175bc | 237 | } |