| /* |
| * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| * All rights reserved |
| * Allocating a pseudo-terminal, and making it the controlling tty. |
| * |
| * As far as I am concerned, the code I have written for this software |
| * can be used freely for any purpose. Any derived versions of this |
| * software must be clearly marked as such, and if the derived work is |
| * incompatible with the protocol description in the RFC file, it must be |
| * called by a name other than "ssh" or "Secure Shell". |
| */ |
| |
| #include "includes.h" |
| RCSID("$OpenBSD: sshpty.c,v 1.13 2006/02/07 01:42:00 stevesk Exp $"); |
| |
| #include <termios.h> |
| |
| #ifdef HAVE_UTIL_H |
| # include <util.h> |
| #endif /* HAVE_UTIL_H */ |
| |
| #include "sshpty.h" |
| #include "log.h" |
| #include "misc.h" |
| |
| #ifdef HAVE_PTY_H |
| # include <pty.h> |
| #endif |
| |
| #ifndef O_NOCTTY |
| #define O_NOCTTY 0 |
| #endif |
| |
| /* |
| * Allocates and opens a pty. Returns 0 if no pty could be allocated, or |
| * nonzero if a pty was successfully allocated. On success, open file |
| * descriptors for the pty and tty sides and the name of the tty side are |
| * returned (the buffer must be able to hold at least 64 characters). |
| */ |
| |
| int |
| pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen) |
| { |
| /* openpty(3) exists in OSF/1 and some other os'es */ |
| char *name; |
| int i; |
| |
| i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); |
| if (i < 0) { |
| error("openpty: %.100s", strerror(errno)); |
| return 0; |
| } |
| name = ttyname(*ttyfd); |
| if (!name) |
| fatal("openpty returns device for which ttyname fails."); |
| |
| strlcpy(namebuf, name, namebuflen); /* possible truncation */ |
| return 1; |
| } |
| |
| /* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ |
| |
| void |
| pty_release(const char *tty) |
| { |
| if (chown(tty, (uid_t) 0, (gid_t) 0) < 0) |
| error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno)); |
| if (chmod(tty, (mode_t) 0666) < 0) |
| error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno)); |
| } |
| |
| /* Makes the tty the process's controlling tty and sets it to sane modes. */ |
| |
| void |
| pty_make_controlling_tty(int *ttyfd, const char *tty) |
| { |
| int fd; |
| #ifdef USE_VHANGUP |
| void *old; |
| #endif /* USE_VHANGUP */ |
| |
| #ifdef _UNICOS |
| if (setsid() < 0) |
| error("setsid: %.100s", strerror(errno)); |
| |
| fd = open(tty, O_RDWR|O_NOCTTY); |
| if (fd != -1) { |
| signal(SIGHUP, SIG_IGN); |
| ioctl(fd, TCVHUP, (char *)NULL); |
| signal(SIGHUP, SIG_DFL); |
| setpgid(0, 0); |
| close(fd); |
| } else { |
| error("Failed to disconnect from controlling tty."); |
| } |
| |
| debug("Setting controlling tty using TCSETCTTY."); |
| ioctl(*ttyfd, TCSETCTTY, NULL); |
| fd = open("/dev/tty", O_RDWR); |
| if (fd < 0) |
| error("%.100s: %.100s", tty, strerror(errno)); |
| close(*ttyfd); |
| *ttyfd = fd; |
| #else /* _UNICOS */ |
| |
| /* First disconnect from the old controlling tty. */ |
| #ifdef TIOCNOTTY |
| fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
| if (fd >= 0) { |
| (void) ioctl(fd, TIOCNOTTY, NULL); |
| close(fd); |
| } |
| #endif /* TIOCNOTTY */ |
| if (setsid() < 0) |
| error("setsid: %.100s", strerror(errno)); |
| |
| /* |
| * Verify that we are successfully disconnected from the controlling |
| * tty. |
| */ |
| fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
| if (fd >= 0) { |
| error("Failed to disconnect from controlling tty."); |
| close(fd); |
| } |
| /* Make it our controlling tty. */ |
| #ifdef TIOCSCTTY |
| debug("Setting controlling tty using TIOCSCTTY."); |
| if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) |
| error("ioctl(TIOCSCTTY): %.100s", strerror(errno)); |
| #endif /* TIOCSCTTY */ |
| #ifdef NEED_SETPGRP |
| if (setpgrp(0,0) < 0) |
| error("SETPGRP %s",strerror(errno)); |
| #endif /* NEED_SETPGRP */ |
| #ifdef USE_VHANGUP |
| old = signal(SIGHUP, SIG_IGN); |
| vhangup(); |
| signal(SIGHUP, old); |
| #endif /* USE_VHANGUP */ |
| fd = open(tty, O_RDWR); |
| if (fd < 0) { |
| error("%.100s: %.100s", tty, strerror(errno)); |
| } else { |
| #ifdef USE_VHANGUP |
| close(*ttyfd); |
| *ttyfd = fd; |
| #else /* USE_VHANGUP */ |
| close(fd); |
| #endif /* USE_VHANGUP */ |
| } |
| /* Verify that we now have a controlling tty. */ |
| fd = open(_PATH_TTY, O_WRONLY); |
| if (fd < 0) |
| error("open /dev/tty failed - could not set controlling tty: %.100s", |
| strerror(errno)); |
| else |
| close(fd); |
| #endif /* _UNICOS */ |
| } |
| |
| /* Changes the window size associated with the pty. */ |
| |
| void |
| pty_change_window_size(int ptyfd, int row, int col, |
| int xpixel, int ypixel) |
| { |
| struct winsize w; |
| |
| w.ws_row = row; |
| w.ws_col = col; |
| w.ws_xpixel = xpixel; |
| w.ws_ypixel = ypixel; |
| (void) ioctl(ptyfd, TIOCSWINSZ, &w); |
| } |
| |
| void |
| pty_setowner(struct passwd *pw, const char *tty) |
| { |
| struct group *grp; |
| gid_t gid; |
| mode_t mode; |
| struct stat st; |
| |
| /* Determine the group to make the owner of the tty. */ |
| grp = getgrnam("tty"); |
| if (grp) { |
| gid = grp->gr_gid; |
| mode = S_IRUSR | S_IWUSR | S_IWGRP; |
| } else { |
| gid = pw->pw_gid; |
| mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; |
| } |
| |
| /* |
| * Change owner and mode of the tty as required. |
| * Warn but continue if filesystem is read-only and the uids match/ |
| * tty is owned by root. |
| */ |
| if (stat(tty, &st)) |
| fatal("stat(%.100s) failed: %.100s", tty, |
| strerror(errno)); |
| |
| if (st.st_uid != pw->pw_uid || st.st_gid != gid) { |
| if (chown(tty, pw->pw_uid, gid) < 0) { |
| if (errno == EROFS && |
| (st.st_uid == pw->pw_uid || st.st_uid == 0)) |
| debug("chown(%.100s, %u, %u) failed: %.100s", |
| tty, (u_int)pw->pw_uid, (u_int)gid, |
| strerror(errno)); |
| else |
| fatal("chown(%.100s, %u, %u) failed: %.100s", |
| tty, (u_int)pw->pw_uid, (u_int)gid, |
| strerror(errno)); |
| } |
| } |
| |
| if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { |
| if (chmod(tty, mode) < 0) { |
| if (errno == EROFS && |
| (st.st_mode & (S_IRGRP | S_IROTH)) == 0) |
| debug("chmod(%.100s, 0%o) failed: %.100s", |
| tty, (u_int)mode, strerror(errno)); |
| else |
| fatal("chmod(%.100s, 0%o) failed: %.100s", |
| tty, (u_int)mode, strerror(errno)); |
| } |
| } |
| } |