diff options
Diffstat (limited to 'sshpty.c')
| -rw-r--r-- | sshpty.c | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/sshpty.c b/sshpty.c new file mode 100644 index 0000000..3526ff0 --- /dev/null +++ b/sshpty.c @@ -0,0 +1,412 @@ +/* + * Dropbear - a SSH2 server + * + * Copied from OpenSSH-3.5p1 source, modified by Matt Johnston 2003 + * + * 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". + */ + +/*RCSID("OpenBSD: sshpty.c,v 1.7 2002/06/24 17:57:20 deraadt Exp ");*/ + +#include "includes.h" +#include "dbutil.h" +#include "errno.h" +#include "sshpty.h" + +/* Pty allocated with _getpty gets broken if we do I_PUSH:es to it. */ +#if defined(HAVE__GETPTY) || defined(HAVE_OPENPTY) +#undef HAVE_DEV_PTMX +#endif + +#ifdef HAVE_PTY_H +# include <pty.h> +#endif +#if defined(USE_DEV_PTMX) && defined(HAVE_STROPTS_H) +# include <stropts.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) +{ +#if defined(HAVE_OPENPTY) + /* exists in recent (4.4) BSDs and OSF/1 */ + char *name; + int i; + + i = openpty(ptyfd, ttyfd, NULL, NULL, NULL); + if (i < 0) { + dropbear_log(LOG_WARNING, + "pty_allocate: openpty: %.100s", strerror(errno)); + return 0; + } + name = ttyname(*ttyfd); + if (!name) { + dropbear_exit("ttyname fails for openpty device"); + } + + strlcpy(namebuf, name, namebuflen); /* possible truncation */ + return 1; +#else /* HAVE_OPENPTY */ +#ifdef HAVE__GETPTY + /* + * _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more + * pty's automagically when needed + */ + char *slave; + + slave = _getpty(ptyfd, O_RDWR, 0622, 0); + if (slave == NULL) { + dropbear_log(LOG_WARNING, + "pty_allocate: _getpty: %.100s", strerror(errno)); + return 0; + } + strlcpy(namebuf, slave, namebuflen); + /* Open the slave side. */ + *ttyfd = open(namebuf, O_RDWR | O_NOCTTY); + if (*ttyfd < 0) { + dropbear_log(LOG_WARNING, + "pty_allocate error: ttyftd open error"); + close(*ptyfd); + return 0; + } + return 1; +#else /* HAVE__GETPTY */ +#if defined(USE_DEV_PTMX) + /* + * This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3 + * also has bsd-style ptys, but they simply do not work.) + * + * Linux systems may have the /dev/ptmx device, but this code won't work. + */ + int ptm; + char *pts; + + ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY); + if (ptm < 0) { + dropbear_log(LOG_WARNING, + "pty_allocate: /dev/ptmx: %.100s", strerror(errno)); + return 0; + } + if (grantpt(ptm) < 0) { + dropbear_log(LOG_WARNING, + "grantpt: %.100s", strerror(errno)); + return 0; + } + if (unlockpt(ptm) < 0) { + dropbear_log(LOG_WARNING, + "unlockpt: %.100s", strerror(errno)); + return 0; + } + pts = ptsname(ptm); + if (pts == NULL) { + dropbear_log(LOG_WARNING, + "Slave pty side name could not be obtained."); + } + strlcpy(namebuf, pts, namebuflen); + *ptyfd = ptm; + + /* Open the slave side. */ + *ttyfd = open(namebuf, O_RDWR | O_NOCTTY); + if (*ttyfd < 0) { + dropbear_log(LOG_ERR, + "error opening pts %.100s: %.100s", namebuf, strerror(errno)); + close(*ptyfd); + return 0; + } +#ifndef HAVE_CYGWIN + /* + * Push the appropriate streams modules, as described in Solaris pts(7). + * HP-UX pts(7) doesn't have ttcompat module. + */ + if (ioctl(*ttyfd, I_PUSH, "ptem") < 0) { + dropbear_log(LOG_WARNING, + "ioctl I_PUSH ptem: %.100s", strerror(errno)); + } + if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0) { + dropbear_log(LOG_WARNING, + "ioctl I_PUSH ldterm: %.100s", strerror(errno)); + } +#ifndef __hpux + if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0) { + dropbear_log(LOG_WARNING, + "ioctl I_PUSH ttcompat: %.100s", strerror(errno)); + } +#endif +#endif + return 1; +#else /* USE_DEV_PTMX */ +#ifdef HAVE_DEV_PTS_AND_PTC + /* AIX-style pty code. */ + const char *name; + + *ptyfd = open("/dev/ptc", O_RDWR | O_NOCTTY); + if (*ptyfd < 0) { + dropbear_log(LOG_ERR, + "Could not open /dev/ptc: %.100s", strerror(errno)); + return 0; + } + name = ttyname(*ptyfd); + if (!name) { + dropbear_exit("ttyname fails for /dev/ptc device"); + } + strlcpy(namebuf, name, namebuflen); + *ttyfd = open(name, O_RDWR | O_NOCTTY); + if (*ttyfd < 0) { + dropbear_log(LOG_ERR, + "Could not open pty slave side %.100s: %.100s", + name, strerror(errno)); + close(*ptyfd); + return 0; + } + return 1; +#else /* HAVE_DEV_PTS_AND_PTC */ + + /* BSD-style pty code. */ + char buf[64]; + int i; + const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ"; + const char *ptyminors = "0123456789abcdef"; + int num_minors = strlen(ptyminors); + int num_ptys = strlen(ptymajors) * num_minors; + struct termios tio; + + for (i = 0; i < num_ptys; i++) { + snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors], + ptyminors[i % num_minors]); + snprintf(namebuf, namebuflen, "/dev/tty%c%c", + ptymajors[i / num_minors], ptyminors[i % num_minors]); + + *ptyfd = open(buf, O_RDWR | O_NOCTTY); + if (*ptyfd < 0) { + /* Try SCO style naming */ + snprintf(buf, sizeof buf, "/dev/ptyp%d", i); + snprintf(namebuf, namebuflen, "/dev/ttyp%d", i); + *ptyfd = open(buf, O_RDWR | O_NOCTTY); + if (*ptyfd < 0) { + continue; + } + } + + /* Open the slave side. */ + *ttyfd = open(namebuf, O_RDWR | O_NOCTTY); + if (*ttyfd < 0) { + dropbear_log(LOG_ERR, + "pty_allocate: %.100s: %.100s", namebuf, strerror(errno)); + close(*ptyfd); + return 0; + } + /* set tty modes to a sane state for broken clients */ + if (tcgetattr(*ptyfd, &tio) < 0) { + dropbear_log(LOG_WARNING, + "ptyallocate: tty modes failed: %.100s", strerror(errno)); + } else { + tio.c_lflag |= (ECHO | ISIG | ICANON); + tio.c_oflag |= (OPOST | ONLCR); + tio.c_iflag |= ICRNL; + + /* Set the new modes for the terminal. */ + if (tcsetattr(*ptyfd, TCSANOW, &tio) < 0) { + dropbear_log(LOG_WARNING, + "Setting tty modes for pty failed: %.100s", + strerror(errno)); + } + } + + return 1; + } + dropbear_log(LOG_WARNING, "failed to open any /dev/pty?? devices"); + return 0; +#endif /* HAVE_DEV_PTS_AND_PTC */ +#endif /* USE_DEV_PTMX */ +#endif /* HAVE__GETPTY */ +#endif /* HAVE_OPENPTY */ +} + +/* Releases the tty. Its ownership is returned to root, and permissions to 0666. */ + +void +pty_release(const char *tty_name) +{ + if (chown(tty_name, (uid_t) 0, (gid_t) 0) < 0 + && (errno != ENOENT)) { + dropbear_log(LOG_ERR, + "chown %.100s 0 0 failed: %.100s", tty_name, strerror(errno)); + } + if (chmod(tty_name, (mode_t) 0666) < 0 + && (errno != ENOENT)) { + dropbear_log(LOG_ERR, + "chmod %.100s 0666 failed: %.100s", tty_name, strerror(errno)); + } +} + +/* Makes the tty the processes controlling tty and sets it to sane modes. */ + +void +pty_make_controlling_tty(int *ttyfd, const char *tty_name) +{ + int fd; +#ifdef USE_VHANGUP + void *old; +#endif /* USE_VHANGUP */ + + /* Solaris has a problem with TIOCNOTTY for a bg process, so + * we disable the signal which would STOP the process - matt */ + signal(SIGTTOU, SIG_IGN); + + /* 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) { + dropbear_log(LOG_ERR, + "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) { + dropbear_log(LOG_ERR, + "Failed to disconnect from controlling tty.\n"); + close(fd); + } + /* Make it our controlling tty. */ +#ifdef TIOCSCTTY + if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0) { + dropbear_log(LOG_ERR, + "ioctl(TIOCSCTTY): %.100s", strerror(errno)); + } +#endif /* TIOCSCTTY */ +#ifdef HAVE_NEWS4 + if (setpgrp(0,0) < 0) { + dropbear_log(LOG_ERR, + error("SETPGRP %s",strerror(errno))); + } +#endif /* HAVE_NEWS4 */ +#ifdef USE_VHANGUP + old = mysignal(SIGHUP, SIG_IGN); + vhangup(); + mysignal(SIGHUP, old); +#endif /* USE_VHANGUP */ + fd = open(tty_name, O_RDWR); + if (fd < 0) { + dropbear_log(LOG_ERR, + "%.100s: %.100s", tty_name, 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) { + dropbear_log(LOG_ERR, + "open /dev/tty failed - could not set controlling tty: %.100s", + strerror(errno)); + } else { + close(fd); + } +} + +/* 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_name) +{ + 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_name, &st)) { + dropbear_exit("pty_setowner: stat(%.101s) failed: %.100s", + tty_name, strerror(errno)); + } + + if (st.st_uid != pw->pw_uid || st.st_gid != gid) { + if (chown(tty_name, pw->pw_uid, gid) < 0) { + if (errno == EROFS && + (st.st_uid == pw->pw_uid || st.st_uid == 0)) { + dropbear_log(LOG_ERR, + "chown(%.100s, %u, %u) failed: %.100s", + tty_name, (unsigned int)pw->pw_uid, (unsigned int)gid, + strerror(errno)); + } else { + dropbear_exit("chown(%.100s, %u, %u) failed: %.100s", + tty_name, (unsigned int)pw->pw_uid, (unsigned int)gid, + strerror(errno)); + } + } + } + + if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) { + if (chmod(tty_name, mode) < 0) { + if (errno == EROFS && + (st.st_mode & (S_IRGRP | S_IROTH)) == 0) { + dropbear_log(LOG_ERR, + "chmod(%.100s, 0%o) failed: %.100s", + tty_name, mode, strerror(errno)); + } else { + dropbear_exit("chmod(%.100s, 0%o) failed: %.100s", + tty_name, mode, strerror(errno)); + } + } + } +} |