420 lines
11 KiB
C
420 lines
11 KiB
C
/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* Allocating a pseudo-terminal, and making it the controlling tty.
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*/
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#include "includes.h"
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RCSID("$OpenBSD: sshpty.c,v 1.7 2002/06/24 17:57:20 deraadt Exp $");
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RCSID("$FreeBSD$");
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#ifdef HAVE_UTIL_H
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# include <util.h>
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#endif /* HAVE_UTIL_H */
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#include "sshpty.h"
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#include "log.h"
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#include "misc.h"
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/* Pty allocated with _getpty gets broken if we do I_PUSH:es to it. */
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#if defined(HAVE__GETPTY) || defined(HAVE_OPENPTY)
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#undef HAVE_DEV_PTMX
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#endif
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#ifdef HAVE_PTY_H
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# include <pty.h>
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#endif
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#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H)
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# include <sys/stropts.h>
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#endif
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#ifndef O_NOCTTY
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#define O_NOCTTY 0
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#endif
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/*
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* Allocates and opens a pty. Returns 0 if no pty could be allocated, or
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* nonzero if a pty was successfully allocated. On success, open file
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* descriptors for the pty and tty sides and the name of the tty side are
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* returned (the buffer must be able to hold at least 64 characters).
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*/
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int
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pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen)
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{
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#if defined(HAVE_OPENPTY) || defined(BSD4_4)
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/* openpty(3) exists in OSF/1 and some other os'es */
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char *name;
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int i;
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i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
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if (i < 0) {
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error("openpty: %.100s", strerror(errno));
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return 0;
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}
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name = ttyname(*ttyfd);
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if (!name)
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fatal("openpty returns device for which ttyname fails.");
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strlcpy(namebuf, name, namebuflen); /* possible truncation */
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return 1;
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#else /* HAVE_OPENPTY */
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#ifdef HAVE__GETPTY
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/*
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* _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more
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* pty's automagically when needed
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*/
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char *slave;
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slave = _getpty(ptyfd, O_RDWR, 0622, 0);
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if (slave == NULL) {
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error("_getpty: %.100s", strerror(errno));
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return 0;
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}
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strlcpy(namebuf, slave, namebuflen);
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/* Open the slave side. */
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*ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
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if (*ttyfd < 0) {
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error("%.200s: %.100s", namebuf, strerror(errno));
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close(*ptyfd);
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return 0;
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}
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return 1;
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#else /* HAVE__GETPTY */
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#if defined(HAVE_DEV_PTMX)
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/*
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* This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3
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* also has bsd-style ptys, but they simply do not work.)
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*/
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int ptm;
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char *pts;
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mysig_t old_signal;
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ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY);
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if (ptm < 0) {
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error("/dev/ptmx: %.100s", strerror(errno));
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return 0;
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}
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old_signal = mysignal(SIGCHLD, SIG_DFL);
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if (grantpt(ptm) < 0) {
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error("grantpt: %.100s", strerror(errno));
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return 0;
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}
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mysignal(SIGCHLD, old_signal);
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if (unlockpt(ptm) < 0) {
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error("unlockpt: %.100s", strerror(errno));
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return 0;
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}
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pts = ptsname(ptm);
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if (pts == NULL)
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error("Slave pty side name could not be obtained.");
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strlcpy(namebuf, pts, namebuflen);
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*ptyfd = ptm;
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/* Open the slave side. */
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*ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
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if (*ttyfd < 0) {
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error("%.100s: %.100s", namebuf, strerror(errno));
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close(*ptyfd);
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return 0;
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}
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#ifndef HAVE_CYGWIN
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/*
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* Push the appropriate streams modules, as described in Solaris pts(7).
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* HP-UX pts(7) doesn't have ttcompat module.
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*/
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if (ioctl(*ttyfd, I_PUSH, "ptem") < 0)
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error("ioctl I_PUSH ptem: %.100s", strerror(errno));
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if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0)
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error("ioctl I_PUSH ldterm: %.100s", strerror(errno));
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#ifndef __hpux
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if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0)
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error("ioctl I_PUSH ttcompat: %.100s", strerror(errno));
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#endif
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#endif
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return 1;
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#else /* HAVE_DEV_PTMX */
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#ifdef HAVE_DEV_PTS_AND_PTC
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/* AIX-style pty code. */
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const char *name;
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*ptyfd = open("/dev/ptc", O_RDWR | O_NOCTTY);
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if (*ptyfd < 0) {
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error("Could not open /dev/ptc: %.100s", strerror(errno));
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return 0;
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}
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name = ttyname(*ptyfd);
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if (!name)
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fatal("Open of /dev/ptc returns device for which ttyname fails.");
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strlcpy(namebuf, name, namebuflen);
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*ttyfd = open(name, O_RDWR | O_NOCTTY);
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if (*ttyfd < 0) {
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error("Could not open pty slave side %.100s: %.100s",
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name, strerror(errno));
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close(*ptyfd);
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return 0;
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}
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return 1;
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#else /* HAVE_DEV_PTS_AND_PTC */
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#ifdef _CRAY
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char buf[64];
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int i;
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int highpty;
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#ifdef _SC_CRAY_NPTY
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highpty = sysconf(_SC_CRAY_NPTY);
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if (highpty == -1)
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highpty = 128;
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#else
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highpty = 128;
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#endif
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for (i = 0; i < highpty; i++) {
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snprintf(buf, sizeof(buf), "/dev/pty/%03d", i);
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*ptyfd = open(buf, O_RDWR|O_NOCTTY);
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if (*ptyfd < 0)
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continue;
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snprintf(namebuf, namebuflen, "/dev/ttyp%03d", i);
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/* Open the slave side. */
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*ttyfd = open(namebuf, O_RDWR|O_NOCTTY);
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if (*ttyfd < 0) {
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error("%.100s: %.100s", namebuf, strerror(errno));
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close(*ptyfd);
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return 0;
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}
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return 1;
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}
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return 0;
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#else
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/* BSD-style pty code. */
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char buf[64];
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int i;
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const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ";
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const char *ptyminors = "0123456789abcdef";
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int num_minors = strlen(ptyminors);
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int num_ptys = strlen(ptymajors) * num_minors;
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struct termios tio;
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for (i = 0; i < num_ptys; i++) {
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snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors],
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ptyminors[i % num_minors]);
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snprintf(namebuf, namebuflen, "/dev/tty%c%c",
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ptymajors[i / num_minors], ptyminors[i % num_minors]);
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*ptyfd = open(buf, O_RDWR | O_NOCTTY);
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if (*ptyfd < 0) {
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/* Try SCO style naming */
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snprintf(buf, sizeof buf, "/dev/ptyp%d", i);
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snprintf(namebuf, namebuflen, "/dev/ttyp%d", i);
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*ptyfd = open(buf, O_RDWR | O_NOCTTY);
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if (*ptyfd < 0)
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continue;
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}
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/* Open the slave side. */
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*ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
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if (*ttyfd < 0) {
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error("%.100s: %.100s", namebuf, strerror(errno));
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close(*ptyfd);
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return 0;
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}
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/* set tty modes to a sane state for broken clients */
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if (tcgetattr(*ptyfd, &tio) < 0)
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log("Getting tty modes for pty failed: %.100s", strerror(errno));
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else {
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tio.c_lflag |= (ECHO | ISIG | ICANON);
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tio.c_oflag |= (OPOST | ONLCR);
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tio.c_iflag |= ICRNL;
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/* Set the new modes for the terminal. */
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if (tcsetattr(*ptyfd, TCSANOW, &tio) < 0)
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log("Setting tty modes for pty failed: %.100s", strerror(errno));
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}
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return 1;
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}
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return 0;
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#endif /* CRAY */
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#endif /* HAVE_DEV_PTS_AND_PTC */
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#endif /* HAVE_DEV_PTMX */
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#endif /* HAVE__GETPTY */
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#endif /* HAVE_OPENPTY */
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}
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/* Releases the tty. Its ownership is returned to root, and permissions to 0666. */
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void
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pty_release(const char *ttyname)
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{
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if (chown(ttyname, (uid_t) 0, (gid_t) 0) < 0)
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error("chown %.100s 0 0 failed: %.100s", ttyname, strerror(errno));
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if (chmod(ttyname, (mode_t) 0666) < 0)
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error("chmod %.100s 0666 failed: %.100s", ttyname, strerror(errno));
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}
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/* Makes the tty the processes controlling tty and sets it to sane modes. */
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void
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pty_make_controlling_tty(int *ttyfd, const char *ttyname)
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{
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int fd;
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#ifdef USE_VHANGUP
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void *old;
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#endif /* USE_VHANGUP */
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#ifdef _CRAY
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if (setsid() < 0)
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error("setsid: %.100s", strerror(errno));
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fd = open(ttyname, O_RDWR|O_NOCTTY);
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if (fd != -1) {
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mysignal(SIGHUP, SIG_IGN);
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ioctl(fd, TCVHUP, (char *)NULL);
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mysignal(SIGHUP, SIG_DFL);
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setpgid(0, 0);
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close(fd);
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} else {
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error("Failed to disconnect from controlling tty.");
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}
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debug("Setting controlling tty using TCSETCTTY.");
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ioctl(*ttyfd, TCSETCTTY, NULL);
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fd = open("/dev/tty", O_RDWR);
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if (fd < 0)
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error("%.100s: %.100s", ttyname, strerror(errno));
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close(*ttyfd);
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*ttyfd = fd;
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#else /* _CRAY */
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/* First disconnect from the old controlling tty. */
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#ifdef TIOCNOTTY
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fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
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if (fd >= 0) {
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(void) ioctl(fd, TIOCNOTTY, NULL);
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close(fd);
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}
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#endif /* TIOCNOTTY */
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if (setsid() < 0)
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error("setsid: %.100s", strerror(errno));
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/*
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* Verify that we are successfully disconnected from the controlling
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* tty.
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*/
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fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
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if (fd >= 0) {
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error("Failed to disconnect from controlling tty.");
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close(fd);
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}
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/* Make it our controlling tty. */
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#ifdef TIOCSCTTY
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debug("Setting controlling tty using TIOCSCTTY.");
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if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
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error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
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#endif /* TIOCSCTTY */
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#ifdef HAVE_NEWS4
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if (setpgrp(0,0) < 0)
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error("SETPGRP %s",strerror(errno));
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#endif /* HAVE_NEWS4 */
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#ifdef USE_VHANGUP
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old = mysignal(SIGHUP, SIG_IGN);
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vhangup();
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mysignal(SIGHUP, old);
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#endif /* USE_VHANGUP */
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fd = open(ttyname, O_RDWR);
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if (fd < 0) {
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error("%.100s: %.100s", ttyname, strerror(errno));
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} else {
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#ifdef USE_VHANGUP
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close(*ttyfd);
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*ttyfd = fd;
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#else /* USE_VHANGUP */
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close(fd);
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#endif /* USE_VHANGUP */
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}
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/* Verify that we now have a controlling tty. */
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fd = open(_PATH_TTY, O_WRONLY);
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if (fd < 0)
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error("open /dev/tty failed - could not set controlling tty: %.100s",
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strerror(errno));
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else
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close(fd);
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#endif /* _CRAY */
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}
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/* Changes the window size associated with the pty. */
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void
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pty_change_window_size(int ptyfd, int row, int col,
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int xpixel, int ypixel)
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{
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struct winsize w;
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w.ws_row = row;
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w.ws_col = col;
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w.ws_xpixel = xpixel;
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w.ws_ypixel = ypixel;
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(void) ioctl(ptyfd, TIOCSWINSZ, &w);
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}
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void
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pty_setowner(struct passwd *pw, const char *ttyname)
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{
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struct group *grp;
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gid_t gid;
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mode_t mode;
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struct stat st;
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/* Determine the group to make the owner of the tty. */
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grp = getgrnam("tty");
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if (grp) {
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gid = grp->gr_gid;
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mode = S_IRUSR | S_IWUSR | S_IWGRP;
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} else {
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gid = pw->pw_gid;
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mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
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}
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/*
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* Change owner and mode of the tty as required.
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* Warn but continue if filesystem is read-only and the uids match/
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* tty is owned by root.
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*/
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if (stat(ttyname, &st))
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fatal("stat(%.100s) failed: %.100s", ttyname,
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strerror(errno));
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if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
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if (chown(ttyname, pw->pw_uid, gid) < 0) {
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if (errno == EROFS &&
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(st.st_uid == pw->pw_uid || st.st_uid == 0))
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error("chown(%.100s, %u, %u) failed: %.100s",
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ttyname, (u_int)pw->pw_uid, (u_int)gid,
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strerror(errno));
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else
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fatal("chown(%.100s, %u, %u) failed: %.100s",
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ttyname, (u_int)pw->pw_uid, (u_int)gid,
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strerror(errno));
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}
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}
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if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
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if (chmod(ttyname, mode) < 0) {
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if (errno == EROFS &&
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(st.st_mode & (S_IRGRP | S_IROTH)) == 0)
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error("chmod(%.100s, 0%o) failed: %.100s",
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ttyname, mode, strerror(errno));
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else
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fatal("chmod(%.100s, 0%o) failed: %.100s",
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ttyname, mode, strerror(errno));
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}
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}
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}
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