openssh/sshpty.c

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/* $OpenBSD: sshpty.c,v 1.34 2019/07/04 16:20:10 deraadt Exp $ */
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/*
* 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.
*
- (djm) Merge OpenBSD changes: - markus@cvs.openbsd.org 2000/09/05 02:59:57 [session.c] print hostname (not hushlogin) - markus@cvs.openbsd.org 2000/09/05 13:18:48 [authfile.c ssh-add.c] enable ssh-add -d for DSA keys - markus@cvs.openbsd.org 2000/09/05 13:20:49 [sftp-server.c] cleanup - markus@cvs.openbsd.org 2000/09/06 03:46:41 [authfile.h] prototype - deraadt@cvs.openbsd.org 2000/09/07 14:27:56 [ALL] cleanup copyright notices on all files. I have attempted to be accurate with the details. everything is now under Tatu's licence (which I copied from his readme), and/or the core-sdi bsd-ish thing for deattack, or various openbsd developers under a 2-term bsd licence. We're not changing any rules, just being accurate. - markus@cvs.openbsd.org 2000/09/07 14:40:30 [channels.c channels.h clientloop.c serverloop.c ssh.c] cleanup window and packet sizes for ssh2 flow control; ok niels - markus@cvs.openbsd.org 2000/09/07 14:53:00 [scp.c] typo - markus@cvs.openbsd.org 2000/09/07 15:13:37 [auth-options.c auth-options.h auth-rh-rsa.c auth-rsa.c auth.c] [authfile.h canohost.c channels.h compat.c hostfile.h log.c match.h] [pty.c readconf.c] some more Copyright fixes - markus@cvs.openbsd.org 2000/09/08 03:02:51 [README.openssh2] bye bye - deraadt@cvs.openbsd.org 2000/09/11 18:38:33 [LICENCE cipher.c] a few more comments about it being ARC4 not RC4 - markus@cvs.openbsd.org 2000/09/12 14:53:11 [log-client.c log-server.c log.c ssh.1 ssh.c ssh.h sshd.8 sshd.c] multiple debug levels - markus@cvs.openbsd.org 2000/09/14 14:25:15 [clientloop.c] typo - deraadt@cvs.openbsd.org 2000/09/15 01:13:51 [ssh-agent.c] check return value for setenv(3) for failure, and deal appropriately
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* 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".
*/
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#include "includes.h"
#include <sys/types.h>
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
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#include <sys/ioctl.h>
#include <sys/stat.h>
#include <signal.h>
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#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#ifdef HAVE_PATHS_H
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# include <paths.h>
#endif
#include <pwd.h>
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
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#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <termios.h>
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#ifdef HAVE_UTIL_H
# include <util.h>
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
2006-08-05 02:39:39 +00:00
#endif
#include <unistd.h>
#include "sshpty.h"
Hopefully things did not get mixed around too much. It compiles under Linux and works. So that is at least a good sign. =) 20010122 - (bal) OpenBSD Resync - markus@cvs.openbsd.org 2001/01/19 12:45:26 GMT 2001 by markus [servconf.c ssh.h sshd.c] only auth-chall.c needs #ifdef SKEY - markus@cvs.openbsd.org 2001/01/19 15:55:10 GMT 2001 by markus [auth-krb4.c auth-options.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth1.c auth2.c channels.c clientloop.c dh.c dispatch.c nchan.c packet.c pathname.h readconf.c scp.c servconf.c serverloop.c session.c ssh-add.c ssh-keygen.c ssh-keyscan.c ssh.c ssh.h ssh1.h sshconnect1.c sshd.c ttymodes.c] move ssh1 definitions to ssh1.h, pathnames to pathnames.h - markus@cvs.openbsd.org 2001/01/19 16:48:14 [sshd.8] fix typo; from stevesk@ - markus@cvs.openbsd.org 2001/01/19 16:50:58 [ssh-dss.c] clear and free digest, make consistent with other code (use dlen); from stevesk@ - markus@cvs.openbsd.org 2001/01/20 15:55:20 GMT 2001 by markus [auth-options.c auth-options.h auth-rsa.c auth2.c] pass the filename to auth_parse_options() - markus@cvs.openbsd.org 2001/01/20 17:59:40 GMT 2001 [readconf.c] fix SIGSEGV from -o ""; problem noted by jehsom@togetherweb.com - stevesk@cvs.openbsd.org 2001/01/20 18:20:29 [sshconnect2.c] dh_new_group() does not return NULL. ok markus@ - markus@cvs.openbsd.org 2001/01/20 21:33:42 [ssh-add.c] do not loop forever if askpass does not exist; from andrew@pimlott.ne.mediaone.net - djm@cvs.openbsd.org 2001/01/20 23:00:56 [servconf.c] Check for NULL return from strdelim; ok markus - djm@cvs.openbsd.org 2001/01/20 23:02:07 [readconf.c] KNF; ok markus - jakob@cvs.openbsd.org 2001/01/21 9:00:33 [ssh-keygen.1] remove -R flag; ok markus@ - markus@cvs.openbsd.org 2001/01/21 19:05:40 [atomicio.c automicio.h auth-chall.c auth-krb4.c auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c auth.c auth.h auth1.c auth2-chall.c auth2.c authfd.c authfile.c bufaux.c bufaux.h buffer.c canahost.c canahost.h channels.c cipher.c cli.c clientloop.c clientloop.h compat.c compress.c deattack.c dh.c dispatch.c groupaccess.c hmac.c hostfile.c kex.c key.c key.h log-client.c log-server.c log.c log.h login.c login.h match.c misc.c misc.h nchan.c packet.c pty.c radix.h readconf.c readpass.c readpass.h rsa.c scp.c servconf.c serverloop.c serverloop.h session.c sftp-server.c ssh-add.c ssh-agent.c ssh-dss.c ssh-keygen.c ssh-keyscan.c ssh-rsa.c ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c sshd.c tildexpand.c tildexpand.h ttysmodes.c uidswap.c xmalloc.c] split ssh.h and try to cleanup the #include mess. remove unnecessary #includes. rename util.[ch] -> misc.[ch] - (bal) renamed 'PIDDIR' to '_PATH_SSH_PIDDIR' to match OpenBSD tree - (bal) Moved #ifdef KRB4 in auth-krb4.c above the #include to resolve conflict when compiling for non-kerb install - (bal) removed the #ifdef SKEY in auth1.c to match Markus' changes on 1/19.
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#include "log.h"
#include "misc.h"
#ifdef HAVE_PTY_H
# include <pty.h>
#endif
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#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif
#ifdef __APPLE__
# include <AvailabilityMacros.h>
# if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5)
# define __APPLE_PRIVPTY__
# endif
#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).
*/
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int
pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
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{
/* openpty(3) exists in OSF/1 and some other os'es */
char *name;
int i;
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i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
if (i == -1) {
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;
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}
/* Releases the tty. Its ownership is returned to root, and permissions to 0666. */
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void
pty_release(const char *tty)
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{
#if !defined(__APPLE_PRIVPTY__) && !defined(HAVE_OPENPTY)
if (chown(tty, (uid_t) 0, (gid_t) 0) == -1)
error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno));
if (chmod(tty, (mode_t) 0666) == -1)
error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno));
#endif /* !__APPLE_PRIVPTY__ && !HAVE_OPENPTY */
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}
/* Makes the tty the process's controlling tty and sets it to sane modes. */
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void
pty_make_controlling_tty(int *ttyfd, const char *tty)
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{
int fd;
/* First disconnect from the old controlling tty. */
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#ifdef TIOCNOTTY
fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
if (fd >= 0) {
(void) ioctl(fd, TIOCNOTTY, NULL);
close(fd);
}
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#endif /* TIOCNOTTY */
if (setsid() == -1)
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. */
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#ifdef TIOCSCTTY
debug("Setting controlling tty using TIOCSCTTY.");
if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
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#endif /* TIOCSCTTY */
#ifdef NEED_SETPGRP
if (setpgrp(0,0) < 0)
error("SETPGRP %s",strerror(errno));
#endif /* NEED_SETPGRP */
fd = open(tty, O_RDWR);
if (fd == -1)
error("%.100s: %.100s", tty, strerror(errno));
else
close(fd);
/* Verify that we now have a controlling tty. */
fd = open(_PATH_TTY, O_WRONLY);
if (fd == -1)
error("open /dev/tty failed - could not set controlling tty: %.100s",
strerror(errno));
else
close(fd);
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}
/* Changes the window size associated with the pty. */
void
pty_change_window_size(int ptyfd, u_int row, u_int col,
u_int xpixel, u_int ypixel)
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{
struct winsize w;
/* may truncate u_int -> u_short */
w.ws_row = row;
w.ws_col = col;
w.ws_xpixel = xpixel;
w.ws_ypixel = ypixel;
(void) ioctl(ptyfd, TIOCSWINSZ, &w);
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}
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 == NULL)
debug("%s: no tty group", __func__);
gid = (grp != NULL) ? grp->gr_gid : pw->pw_gid;
mode = (grp != NULL) ? 0620 : 0600;
/*
* 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) == -1)
fatal("stat(%.100s) failed: %.100s", tty,
strerror(errno));
#ifdef WITH_SELINUX
ssh_selinux_setup_pty(pw->pw_name, tty);
#endif
if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
if (chown(tty, pw->pw_uid, gid) == -1) {
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) == -1) {
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));
}
}
}
/* Disconnect from the controlling tty. */
void
disconnect_controlling_tty(void)
{
#ifdef TIOCNOTTY
int fd;
if ((fd = open(_PATH_TTY, O_RDWR | O_NOCTTY)) >= 0) {
(void) ioctl(fd, TIOCNOTTY, NULL);
close(fd);
}
#endif /* TIOCNOTTY */
}