--- rxvt-unicode/src/ptytty.C 2004/08/13 03:36:57 1.12 +++ rxvt-unicode/src/ptytty.C 2006/01/22 12:23:55 1.58 @@ -1,10 +1,14 @@ -/*--------------------------------*-C-*---------------------------------* +// This file is part of libptytty. Do not make local modifications. +// http://software.schmorp.de/pkg/libptytty + +/*----------------------------------------------------------------------* * File: ptytty.C *----------------------------------------------------------------------* * * All portions of code are copyright by their respective author/s. * Copyright (c) 1999-2001 Geoff Wing - * Copyright (c) 2004 Marc Lehmann + * Copyright (c) 2004-2006 Marc Lehmann + * Copyright (c) 2006 Emanuele Giaquinta * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -21,50 +25,42 @@ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *---------------------------------------------------------------------*/ -#include "../config.h" /* NECESSARY */ +#include "../config.h" -/* - * Try to be self-contained except for the above autoconfig'd defines - */ +#include "ptytty.h" -#if 0 -#ifdef HAVE_GETPT -# define _GNU_SOURCE -#endif -#endif +#include +#include + +#include +#include +#include +#include -#include -#ifdef HAVE_STDLIB_H -# include -#endif -#ifdef HAVE_SYS_TYPES_H -# include -#endif -#ifdef HAVE_UNISTD_H -# include -#endif -#if defined(HAVE_STRING_H) -# include -#endif -#ifdef HAVE_FCNTL_H -# include -#endif #ifdef HAVE_SYS_IOCTL_H # include #endif -#if defined(PTYS_ARE_PTMX) && defined(HAVE_SYS_STROPTS_H) +#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) # include /* for I_PUSH */ #endif #ifdef HAVE_ISASTREAM # include #endif - -#ifdef DEBUG_TTY -# define D_TTY(x) fprintf x ; fputc('\n', stderr) ; fflush(stderr) -#else -# define D_TTY(x) +#if defined(HAVE_PTY_H) +# include +#elif defined(HAVE_LIBUTIL_H) +# include +#elif defined(HAVE_UTIL_H) +# include +#endif +#ifdef TTY_GID_SUPPORT +#include #endif +#include + +///////////////////////////////////////////////////////////////////////////// + /* ------------------------------------------------------------------------- * * GET PSEUDO TELETYPE - MASTER AND SLAVE * * ------------------------------------------------------------------------- */ @@ -73,156 +69,129 @@ * If successful, ttydev is set to the name of the slave device. * fd_tty _may_ also be set to an open fd to the slave device */ -/* EXTPROTO */ -int -rxvt_get_pty (int *fd_tty, const char **ttydev) +#if defined(UNIX98_PTY) +static int +get_pty (int *fd_tty, char **ttydev) { int pfd; -#ifdef PTYS_ARE_OPENPTY +# if defined(HAVE_GETPT) + pfd = getpt(); +# elif defined(HAVE_POSIX_OPENPT) + pfd = posix_openpt (O_RDWR); +# else + pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); +# endif + if (pfd >= 0) + { + if (grantpt (pfd) == 0 /* change slave permissions */ + && unlockpt (pfd) == 0) + { /* slave now unlocked */ + *ttydev = strdup (ptsname (pfd)); /* get slave's name */ + return pfd; + } - char tty_name[sizeof "/dev/pts/????\0"]; + close (pfd); + } - if (openpty (&pfd, fd_tty, tty_name, NULL, NULL) != -1) + return -1; +} +#elif defined(HAVE_OPENPTY) +static int +get_pty (int *fd_tty, char **ttydev) +{ + int pfd; + int res; + char tty_name[32]; + + res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); + if (res != -1) { *ttydev = strdup (tty_name); return pfd; } -#endif -#ifdef PTYS_ARE__GETPTY + return -1; +} +#elif defined(HAVE__GETPTY) +static int +get_pty (int *fd_tty, char **ttydev) +{ + int pfd; + *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); if (*ttydev != NULL) return pfd; -#endif -#ifdef PTYS_ARE_GETPTY - - char *ptydev; - - while ((ptydev = getpty ()) != NULL) - if ((pfd = open (ptydev, O_RDWR | O_NOCTTY, 0)) >= 0) - { - *ttydev = ptydev; - return pfd; - } -#endif - -#if defined(HAVE_GRANTPT) && defined(HAVE_UNLOCKPT) -# if defined(PTYS_ARE_GETPT) || defined(PTYS_ARE_PTMX) - - { -# ifdef PTYS_ARE_GETPT - pfd = getpt (); -# else - - pfd = open ("/dev/ptmx", O_RDWR | O_NOCTTY, 0); -# endif - - if (pfd >= 0) - { - if (grantpt (pfd) == 0 /* change slave permissions */ - && unlockpt (pfd) == 0) - { /* slave now unlocked */ - *ttydev = ptsname (pfd); /* get slave's name */ - return pfd; - } - close (pfd); - } - } -# endif -#endif + return -1; +} +#elif defined(HAVE_DEV_PTC) +static int +get_pty (int *fd_tty, char **ttydev) +{ + int pfd; -#ifdef PTYS_ARE_PTC if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) { - *ttydev = ttyname (pfd); + *ttydev = strdup (ttyname (pfd)); return pfd; } -#endif -#ifdef PTYS_ARE_CLONE + return -1; +} +#elif defined(HAVE_DEV_CLONE) +static int +get_pty (int *fd_tty, char **ttydev) +{ + int pfd; + if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0) { - *ttydev = ptsname (pfd); + *ttydev = strdup (ptsname (pfd)); return pfd; } -#endif -#ifdef PTYS_ARE_NUMERIC - { - int idx; - char *c1, *c2; - char pty_name[] = "/dev/ptyp???"; - char tty_name[] = "/dev/ttyp???"; - - c1 = & (pty_name[sizeof (pty_name) - 4]); - c2 = & (tty_name[sizeof (tty_name) - 4]); - for (idx = 0; idx < 256; idx++) - { - sprintf (c1, "%d", idx); - sprintf (c2, "%d", idx); - if (access (tty_name, F_OK) < 0) - { - idx = 256; - break; - } - if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) >= 0) - { - if (access (tty_name, R_OK | W_OK) == 0) - { - *ttydev = strdup (tty_name); - return pfd; - } - close (pfd); - } - } - } -#endif -#ifdef PTYS_ARE_SEARCHED - { - const char *c1, *c2; - char pty_name[] = "/dev/pty??"; - char tty_name[] = "/dev/tty??"; - -# ifndef PTYCHAR1 -# define PTYCHAR1 "pqrstuvwxyz" -# endif -# ifndef PTYCHAR2 -# define PTYCHAR2 "0123456789abcdef" -# endif - - for (c1 = PTYCHAR1; *c1; c1++) - { - pty_name[ (sizeof (pty_name) - 3)] = - tty_name[ (sizeof (pty_name) - 3)] = *c1; - for (c2 = PTYCHAR2; *c2; c2++) - { - pty_name[ (sizeof (pty_name) - 2)] = - tty_name[ (sizeof (pty_name) - 2)] = *c2; - if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) >= 0) - { - if (access (tty_name, R_OK | W_OK) == 0) - { - *ttydev = strdup (tty_name); - return pfd; - } - close (pfd); - } - } - } - } -#endif return -1; } +#else +/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ +static int +get_pty (int *fd_tty, char **ttydev) +{ + int pfd; + int i; + char pty_name[32]; + char tty_name[32]; + const char *majors = "pqrstuvwxyzabcde"; + const char *minors = "0123456789abcdef"; + for (i = 0; i < 256; i++) + { + snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); + snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]); + if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) + { + snprintf(pty_name, 32, "/dev/ptyp%d", i); + snprintf(tty_name, 32, "/dev/ttyp%d", i); + if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) + continue; + } + if (access (tty_name, R_OK | W_OK) == 0) + { + *ttydev = strdup (tty_name); + return pfd; + } + + close (pfd); + } +} +#endif /*----------------------------------------------------------------------*/ /* * Returns tty file descriptor, or -1 on failure */ -/* EXTPROTO */ -int -rxvt_get_tty (const char *ttydev) +static int +get_tty (char *ttydev) { return open (ttydev, O_RDWR | O_NOCTTY, 0); } @@ -231,41 +200,12 @@ /* * Make our tty a controlling tty so that /dev/tty points to us */ -/* EXTPROTO */ -int -rxvt_control_tty (int fd_tty, const char *ttydev) -{ -#ifndef __QNX__ - int fd; - - D_TTY ((stderr, "rxvt_control_tty (): pid: %d, tty fd: %d, dev: %s", getpid (), fd_tty, ttydev)); - /* ---------------------------------------- */ -# ifdef HAVE_SETSID +static int +control_tty (int fd_tty) +{ setsid (); -# endif -# if defined(HAVE_SETPGID) - setpgid (0, 0); -# elif defined(HAVE_SETPGRP) - setpgrp (0, 0); -# endif - /* ---------------------------------------- */ -# ifdef TIOCNOTTY - fd = open ("/dev/tty", O_RDWR | O_NOCTTY); - D_TTY ((stderr, "rxvt_control_tty (): Voiding tty associations: previous=%s", fd < 0 ? "no" : "yes")); - if (fd >= 0) - { - ioctl (fd, TIOCNOTTY, NULL); /* void tty associations */ - close (fd); - } -# endif - /* ---------------------------------------- */ - fd = open ("/dev/tty", O_RDWR | O_NOCTTY); - D_TTY ((stderr, "rxvt_control_tty (): /dev/tty has controlling tty? %s", fd < 0 ? "no (good)" : "yes (bad)")); - if (fd >= 0) - close (fd); /* ouch: still have controlling tty */ - /* ---------------------------------------- */ -#if defined(PTYS_ARE_PTMX) && defined(I_PUSH) +#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) /* * Push STREAMS modules: * ptem: pseudo-terminal hardware emulation module. @@ -287,36 +227,387 @@ if (isastream (fd_tty) == 1) # endif { - D_TTY ((stderr, "rxvt_control_tty (): Pushing STREAMS modules")); ioctl (fd_tty, I_PUSH, "ptem"); ioctl (fd_tty, I_PUSH, "ldterm"); ioctl (fd_tty, I_PUSH, "ttcompat"); } #endif - /* ---------------------------------------- */ -# if defined(TIOCSCTTY) - fd = ioctl (fd_tty, TIOCSCTTY, NULL); - D_TTY ((stderr, "rxvt_control_tty (): ioctl (..,TIOCSCTTY): %d", fd)); -# elif defined(TIOCSETCTTY) - fd = ioctl (fd_tty, TIOCSETCTTY, NULL); - D_TTY ((stderr, "rxvt_control_tty (): ioctl (..,TIOCSETCTTY): %d", fd)); -# else - fd = open (ttydev, O_RDWR); - D_TTY ((stderr, "rxvt_control_tty (): tty open%s", fd < 0 ? " failure" : "ed OK")); - if (fd >= 0) - close (fd); -# endif - /* ---------------------------------------- */ - fd = open ("/dev/tty", O_WRONLY); - D_TTY ((stderr, "rxvt_control_tty (): do we have controlling tty now: %s", fd < 0 ? "no (fatal)" : "yes (good)")); + + ioctl (fd_tty, TIOCSCTTY, NULL); + + int fd = open ("/dev/tty", O_WRONLY); if (fd < 0) - return -1; /* fatal */ + return -1; /* fatal */ + close (fd); - /* ---------------------------------------- */ - D_TTY ((stderr, "rxvt_control_tty (): tcgetpgrp (): %d getpgrp (): %d", tcgetpgrp (fd_tty), getpgrp ())); - /* ---------------------------------------- */ -#endif /* ! __QNX__ */ return 0; } -/*----------------------- end-of-file (C source) -----------------------*/ + +void +ptytty::close_tty () +{ + if (tty < 0) + return; + + close (tty); + tty = -1; +} + +bool +ptytty::make_controlling_tty () +{ + return control_tty (tty) >= 0; +} + +void +ptytty::set_utf8_mode (bool on) +{ +#ifdef IUTF8 + if (pty < 0) + return; + + struct termios tio; + + if (tcgetattr (pty, &tio) != -1) + { + tcflag_t new_cflag = tio.c_iflag; + + if (on) + new_cflag |= IUTF8; + else + new_cflag &= ~IUTF8; + + if (new_cflag != tio.c_iflag) + { + tio.c_iflag = new_cflag; + tcsetattr (pty, TCSANOW, &tio); + } + } +#endif +} + +static struct ttyconf { + gid_t gid; + mode_t mode; + + ttyconf () + { +#ifdef TTY_GID_SUPPORT + struct group *gr = getgrnam ("tty"); + + if (gr) + { /* change group ownership of tty to "tty" */ + mode = S_IRUSR | S_IWUSR | S_IWGRP; + gid = gr->gr_gid; + } + else +#endif /* TTY_GID_SUPPORT */ + { + mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; + gid = 0; + } + } +} ttyconf; + +ptytty_unix::ptytty_unix () +{ + name = 0; +#if UTMP_SUPPORT + cmd_pid = 0; +#endif +} + +ptytty_unix::~ptytty_unix () +{ +#if UTMP_SUPPORT + logout (); +#endif + put (); +} + +void +ptytty_unix::put () +{ + chmod (name, RESTORE_TTY_MODE); + chown (name, 0, ttyconf.gid); + + close_tty (); + + if (pty >= 0) + close (pty); + + free (name); + + pty = tty = -1; + name = 0; +} + +bool +ptytty_unix::get () +{ + /* get master (pty) */ + if ((pty = get_pty (&tty, &name)) < 0) + return false; + + fcntl (pty, F_SETFL, O_NONBLOCK); + + /* get slave (tty) */ + if (tty < 0) + { +#ifndef NO_SETOWNER_TTYDEV + chown (name, getuid (), ttyconf.gid); /* fail silently */ + chmod (name, ttyconf.mode); +# ifdef HAVE_REVOKE + revoke (name); +# endif +#endif + + if ((tty = get_tty (name)) < 0) + { + put (); + return false; + } + } + + return true; +} + +#if PTYTTY_HELPER + +static int sock_fd = -1; +static int helper_pid, owner_pid; + +struct command +{ + enum { get, login, destroy } type; + + ptytty *id; + + bool login_shell; + int cmd_pid; + char hostname[512]; // arbitrary, but should be plenty +}; + +struct ptytty_proxy : ptytty +{ + ptytty *id; + + ptytty_proxy () + : id(0) + { + } + + ~ptytty_proxy (); + + bool get (); + void login (int cmd_pid, bool login_shell, const char *hostname); +}; + +bool +ptytty_proxy::get () +{ + command cmd; + + cmd.type = command::get; + + write (sock_fd, &cmd, sizeof (cmd)); + + if (read (sock_fd, &id, sizeof (id)) != sizeof (id)) + ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n"); + + if (!id) + return false; + + if ((pty = recv_fd (sock_fd)) < 0 + || (tty = recv_fd (sock_fd)) < 0) + ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n"); + + return true; +} + +void +ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname) +{ + command cmd; + + cmd.type = command::login; + cmd.id = id; + cmd.cmd_pid = cmd_pid; + cmd.login_shell = login_shell; + strncpy (cmd.hostname, hostname, sizeof (cmd.hostname)); + + write (sock_fd, &cmd, sizeof (cmd)); +} + +ptytty_proxy::~ptytty_proxy () +{ + if (id) + { + command cmd; + + cmd.type = command::destroy; + cmd.id = id; + + write (sock_fd, &cmd, sizeof (cmd)); + } +} + +static +void serve () +{ + command cmd; + vector ptys; + + while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command)) + { + if (cmd.type == command::get) + { + // -> id ptyfd ttyfd + cmd.id = new ptytty_unix; + + if (cmd.id->get ()) + { + write (sock_fd, &cmd.id, sizeof (cmd.id)); + ptys.push_back (cmd.id); + + ptytty::send_fd (sock_fd, cmd.id->pty); + ptytty::send_fd (sock_fd, cmd.id->tty); + } + else + { + delete cmd.id; + cmd.id = 0; + write (sock_fd, &cmd.id, sizeof (cmd.id)); + } + } + else if (cmd.type == command::login) + { +#if UTMP_SUPPORT + if (find (ptys.begin (), ptys.end (), cmd.id)) + { + cmd.hostname[sizeof (cmd.hostname) - 1] = 0; + cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname); + } +#endif + } + else if (cmd.type == command::destroy) + { + vector::iterator pty = find (ptys.begin (), ptys.end (), cmd.id); + + if (pty != ptys.end ()) + { + delete *pty; + ptys.erase (pty); + } + } + else + break; + } + + // destroy all ptys + for (vector::iterator i = ptys.end (); i-- > ptys.begin (); ) + delete *i; +} + +void +ptytty::use_helper () +{ + int pid = getpid (); + + if (sock_fd >= 0 && pid == owner_pid) + return; + + owner_pid = pid; + + int sv[2]; + + if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv)) + ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n"); + + helper_pid = fork (); + + if (helper_pid < 0) + ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n"); + + if (helper_pid) + { + // client, process + sock_fd = sv[0]; + close (sv[1]); + fcntl (sock_fd, F_SETFD, FD_CLOEXEC); + } + else + { + // server, pty-helper + sock_fd = sv[1]; + + chdir ("/"); + + for (int fd = 0; fd < 1023; fd++) + if (fd != sock_fd) + close (fd); + + serve (); + _exit (EXIT_SUCCESS); + } +} + +#endif + +ptytty * +ptytty::create () +{ +#if PTYTTY_HELPER + if (helper_pid && getpid () == owner_pid) + // use helper process + return new ptytty_proxy; + else +#endif + return new ptytty_unix; +} + +void +ptytty::init () +{ + uid_t uid = getuid (); + gid_t gid = getgid (); + + // before doing anything else, check for setuid/setgid operation, + // start the helper process and drop privileges + if (uid != geteuid () + || gid != getegid ()) + { +#if PTYTTY_HELPER + use_helper (); +#else + ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n"); +#endif + + drop_privileges (); + } +} + +void +ptytty::drop_privileges () +{ + uid_t uid = getuid (); + gid_t gid = getgid (); + + // drop privileges +#if HAVE_SETRESUID + setresgid (gid, gid, gid); + setresuid (uid, uid, uid); +#elif HAVE_SETREUID + setregid (gid, gid); + setreuid (uid, uid); +#elif HAVE_SETUID + setgid (gid); + setuid (uid); +#endif + + if (uid != geteuid () + || gid != getegid ()) + ptytty_fatal ("unable to drop privileges, aborting.\n"); +} +