diff options
Diffstat (limited to 'ttymodes.c')
| -rw-r--r-- | ttymodes.c | 450 |
1 files changed, 450 insertions, 0 deletions
diff --git a/ttymodes.c b/ttymodes.c new file mode 100644 index 0000000..1d20ce8 --- /dev/null +++ b/ttymodes.c @@ -0,0 +1,450 @@ +/* $OpenBSD: ttymodes.c,v 1.36 2021/01/27 09:26:54 djm Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * + * 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". + */ + +/* + * SSH2 tty modes support by Kevin Steves. + * Copyright (c) 2001 Kevin Steves. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/* + * Encoding and decoding of terminal modes in a portable way. + * Much of the format is defined in ttymodes.h; it is included multiple times + * into this file with the appropriate macro definitions to generate the + * suitable code. + */ + +#include "includes.h" + +#include <sys/types.h> + +#include <errno.h> +#include <string.h> +#include <termios.h> +#include <stdarg.h> + +#include "packet.h" +#include "log.h" +#include "compat.h" +#include "sshbuf.h" +#include "ssherr.h" + +#define TTY_OP_END 0 +/* + * uint32 (u_int) follows speed. + */ +#define TTY_OP_ISPEED 128 +#define TTY_OP_OSPEED 129 + +/* + * Converts POSIX speed_t to a baud rate. The values of the + * constants for speed_t are not themselves portable. + */ +static int +speed_to_baud(speed_t speed) +{ + switch (speed) { + case B0: + return 0; + case B50: + return 50; + case B75: + return 75; + case B110: + return 110; + case B134: + return 134; + case B150: + return 150; + case B200: + return 200; + case B300: + return 300; + case B600: + return 600; + case B1200: + return 1200; + case B1800: + return 1800; + case B2400: + return 2400; + case B4800: + return 4800; + case B9600: + return 9600; + +#ifdef B19200 + case B19200: + return 19200; +#else /* B19200 */ +#ifdef EXTA + case EXTA: + return 19200; +#endif /* EXTA */ +#endif /* B19200 */ + +#ifdef B38400 + case B38400: + return 38400; +#else /* B38400 */ +#ifdef EXTB + case EXTB: + return 38400; +#endif /* EXTB */ +#endif /* B38400 */ + +#ifdef B7200 + case B7200: + return 7200; +#endif /* B7200 */ +#ifdef B14400 + case B14400: + return 14400; +#endif /* B14400 */ +#ifdef B28800 + case B28800: + return 28800; +#endif /* B28800 */ +#ifdef B57600 + case B57600: + return 57600; +#endif /* B57600 */ +#ifdef B76800 + case B76800: + return 76800; +#endif /* B76800 */ +#ifdef B115200 + case B115200: + return 115200; +#endif /* B115200 */ +#ifdef B230400 + case B230400: + return 230400; +#endif /* B230400 */ + default: + return 9600; + } +} + +/* + * Converts a numeric baud rate to a POSIX speed_t. + */ +static speed_t +baud_to_speed(int baud) +{ + switch (baud) { + case 0: + return B0; + case 50: + return B50; + case 75: + return B75; + case 110: + return B110; + case 134: + return B134; + case 150: + return B150; + case 200: + return B200; + case 300: + return B300; + case 600: + return B600; + case 1200: + return B1200; + case 1800: + return B1800; + case 2400: + return B2400; + case 4800: + return B4800; + case 9600: + return B9600; + +#ifdef B19200 + case 19200: + return B19200; +#else /* B19200 */ +#ifdef EXTA + case 19200: + return EXTA; +#endif /* EXTA */ +#endif /* B19200 */ + +#ifdef B38400 + case 38400: + return B38400; +#else /* B38400 */ +#ifdef EXTB + case 38400: + return EXTB; +#endif /* EXTB */ +#endif /* B38400 */ + +#ifdef B7200 + case 7200: + return B7200; +#endif /* B7200 */ +#ifdef B14400 + case 14400: + return B14400; +#endif /* B14400 */ +#ifdef B28800 + case 28800: + return B28800; +#endif /* B28800 */ +#ifdef B57600 + case 57600: + return B57600; +#endif /* B57600 */ +#ifdef B76800 + case 76800: + return B76800; +#endif /* B76800 */ +#ifdef B115200 + case 115200: + return B115200; +#endif /* B115200 */ +#ifdef B230400 + case 230400: + return B230400; +#endif /* B230400 */ + default: + return B9600; + } +} + +/* + * Encode a special character into SSH line format. + */ +static u_int +special_char_encode(cc_t c) +{ +#ifdef _POSIX_VDISABLE + if (c == _POSIX_VDISABLE) + return 255; +#endif /* _POSIX_VDISABLE */ + return c; +} + +/* + * Decode a special character from SSH line format. + */ +static cc_t +special_char_decode(u_int c) +{ +#ifdef _POSIX_VDISABLE + if (c == 255) + return _POSIX_VDISABLE; +#endif /* _POSIX_VDISABLE */ + return c; +} + +/* + * Encodes terminal modes for the terminal referenced by fd + * or tiop in a portable manner, and appends the modes to a packet + * being constructed. + */ +void +ssh_tty_make_modes(struct ssh *ssh, int fd, struct termios *tiop) +{ + struct termios tio; + struct sshbuf *buf; + int r, ibaud, obaud; + + if ((buf = sshbuf_new()) == NULL) + fatal_f("sshbuf_new failed"); + + if (tiop == NULL) { + if (fd == -1) { + debug_f("no fd or tio"); + goto end; + } + if (tcgetattr(fd, &tio) == -1) { + logit("tcgetattr: %.100s", strerror(errno)); + goto end; + } + } else + tio = *tiop; + + /* Store input and output baud rates. */ + obaud = speed_to_baud(cfgetospeed(&tio)); + ibaud = speed_to_baud(cfgetispeed(&tio)); + if ((r = sshbuf_put_u8(buf, TTY_OP_OSPEED)) != 0 || + (r = sshbuf_put_u32(buf, obaud)) != 0 || + (r = sshbuf_put_u8(buf, TTY_OP_ISPEED)) != 0 || + (r = sshbuf_put_u32(buf, ibaud)) != 0) + fatal_fr(r, "compose"); + + /* Store values of mode flags. */ +#define TTYCHAR(NAME, OP) \ + if ((r = sshbuf_put_u8(buf, OP)) != 0 || \ + (r = sshbuf_put_u32(buf, \ + special_char_encode(tio.c_cc[NAME]))) != 0) \ + fatal_fr(r, "compose %s", #NAME); + +#define SSH_TTYMODE_IUTF8 42 /* for SSH_BUG_UTF8TTYMODE */ + +#define TTYMODE(NAME, FIELD, OP) \ + if (OP == SSH_TTYMODE_IUTF8 && (ssh->compat & SSH_BUG_UTF8TTYMODE)) { \ + debug3_f("SSH_BUG_UTF8TTYMODE"); \ + } else if ((r = sshbuf_put_u8(buf, OP)) != 0 || \ + (r = sshbuf_put_u32(buf, ((tio.FIELD & NAME) != 0))) != 0) \ + fatal_fr(r, "compose %s", #NAME); + +#include "ttymodes.h" + +#undef TTYCHAR +#undef TTYMODE + +end: + /* Mark end of mode data. */ + if ((r = sshbuf_put_u8(buf, TTY_OP_END)) != 0 || + (r = sshpkt_put_stringb(ssh, buf)) != 0) + fatal_fr(r, "compose end"); + sshbuf_free(buf); +} + +/* + * Decodes terminal modes for the terminal referenced by fd in a portable + * manner from a packet being read. + */ +void +ssh_tty_parse_modes(struct ssh *ssh, int fd) +{ + struct termios tio; + struct sshbuf *buf; + const u_char *data; + u_char opcode; + u_int baud, u; + int r, failure = 0; + size_t len; + + if ((r = sshpkt_get_string_direct(ssh, &data, &len)) != 0) + fatal_fr(r, "parse"); + if (len == 0) + return; + if ((buf = sshbuf_from(data, len)) == NULL) { + error_f("sshbuf_from failed"); + return; + } + + /* + * Get old attributes for the terminal. We will modify these + * flags. I am hoping that if there are any machine-specific + * modes, they will initially have reasonable values. + */ + if (tcgetattr(fd, &tio) == -1) { + logit("tcgetattr: %.100s", strerror(errno)); + failure = -1; + } + + while (sshbuf_len(buf) > 0) { + if ((r = sshbuf_get_u8(buf, &opcode)) != 0) + fatal_fr(r, "parse opcode"); + switch (opcode) { + case TTY_OP_END: + goto set; + + case TTY_OP_ISPEED: + if ((r = sshbuf_get_u32(buf, &baud)) != 0) + fatal_fr(r, "parse ispeed"); + if (failure != -1 && + cfsetispeed(&tio, baud_to_speed(baud)) == -1) + error("cfsetispeed failed for %d", baud); + break; + + case TTY_OP_OSPEED: + if ((r = sshbuf_get_u32(buf, &baud)) != 0) + fatal_fr(r, "parse ospeed"); + if (failure != -1 && + cfsetospeed(&tio, baud_to_speed(baud)) == -1) + error("cfsetospeed failed for %d", baud); + break; + +#define TTYCHAR(NAME, OP) \ + case OP: \ + if ((r = sshbuf_get_u32(buf, &u)) != 0) \ + fatal_fr(r, "parse %s", #NAME); \ + tio.c_cc[NAME] = special_char_decode(u); \ + break; +#define TTYMODE(NAME, FIELD, OP) \ + case OP: \ + if ((r = sshbuf_get_u32(buf, &u)) != 0) \ + fatal_fr(r, "parse %s", #NAME); \ + if (u) \ + tio.FIELD |= NAME; \ + else \ + tio.FIELD &= ~NAME; \ + break; + +#include "ttymodes.h" + +#undef TTYCHAR +#undef TTYMODE + + default: + debug("Ignoring unsupported tty mode opcode %d (0x%x)", + opcode, opcode); + /* + * SSH2: + * Opcodes 1 to 159 are defined to have a uint32 + * argument. + * Opcodes 160 to 255 are undefined and cause parsing + * to stop. + */ + if (opcode > 0 && opcode < 160) { + if ((r = sshbuf_get_u32(buf, NULL)) != 0) + fatal_fr(r, "parse arg"); + break; + } else { + logit_f("unknown opcode %d", opcode); + goto set; + } + } + } + +set: + len = sshbuf_len(buf); + sshbuf_free(buf); + if (len > 0) { + logit_f("%zu bytes left", len); + return; /* Don't process bytes passed */ + } + if (failure == -1) + return; /* Packet parsed ok but tcgetattr() failed */ + + /* Set the new modes for the terminal. */ + if (tcsetattr(fd, TCSANOW, &tio) == -1) + logit("Setting tty modes failed: %.100s", strerror(errno)); +} |