diff options
| -rw-r--r-- | networking/telnetd.c | 42 |
1 files changed, 24 insertions, 18 deletions
diff --git a/networking/telnetd.c b/networking/telnetd.c index 0da29410e..eaaf29bce 100644 --- a/networking/telnetd.c +++ b/networking/telnetd.c @@ -169,12 +169,10 @@ safe_write_to_pty_decode_iac(struct tsession *ts) handle_iac: /* 2-byte commands (240..250 and 255): * IAC IAC (255) Literal 255. Supported. + * IAC SE (240) End of subnegotiation. Treated as NOP. * IAC NOP (241) NOP. Supported. * IAC BRK (243) Break. Like serial line break. TODO via tcsendbreak()? * IAC AYT (246) Are you there. Send back evidence that AYT was seen. TODO (send NOP back)? - * Implemented only as part of NAWS: - * IAC SB (250) Subnegotiation of an option follows. - * IAC SE (240) End of subnegotiation. * These don't look useful: * IAC DM (242) Data mark. What is this? * IAC IP (244) Suspend, interrupt or abort the process. (Ancient cousin of ^C). @@ -182,8 +180,11 @@ safe_write_to_pty_decode_iac(struct tsession *ts) * IAC EC (247) Erase character. The receiver should delete the last received char. * IAC EL (248) Erase line. The receiver should delete everything up tp last newline. * IAC GA (249) Go ahead. For half-duplex lines: "now you talk". + * Implemented only as part of NAWS: + * IAC SB (250) Subnegotiation of an option follows. */ - if (buf[1] == IAC) { /* Literal 255 (emacs M-DEL) */ + if (buf[1] == IAC) { + /* Literal 255 (emacs M-DEL) */ //bb_error_msg("255!"); rc = safe_write(ts->ptyfd, &buf[1], 1); if (rc <= 0) @@ -191,7 +192,9 @@ safe_write_to_pty_decode_iac(struct tsession *ts) rc = 2; goto update_and_return; } - if (buf[1] == NOP) { /* NOP (241). Ignore (putty keepalive, etc) */ + if (buf[1] >= 240 && buf[1] <= 249) { + /* NOP (241). Ignore (putty keepalive, etc) */ + /* All other 2-byte commands also treated as NOPs here */ rc = 2; goto update_and_return; } @@ -205,24 +208,27 @@ safe_write_to_pty_decode_iac(struct tsession *ts) goto update_and_return; } - /* TELOPT_NAWS support */ - /* IAC SB, TELOPT_NAWS, 4-byte, IAC SE */ - if (buf[1] == SB && buf[2] == TELOPT_NAWS) { - struct winsize ws; - if (wr <= 8) { + if (buf[1] == SB) { + if (buf[2] == TELOPT_NAWS) { + /* IAC SB, TELOPT_NAWS, 4-byte, IAC SE */ + struct winsize ws; + if (wr <= 6) { /* BUG: incomplete, can't process */ - rc = wr; + rc = wr; + goto update_and_return; + } + memset(&ws, 0, sizeof(ws)); /* pixel sizes are set to 0 */ + ws.ws_col = (buf[3] << 8) | buf[4]; + ws.ws_row = (buf[5] << 8) | buf[6]; + ioctl(ts->ptyfd, TIOCSWINSZ, (char *)&ws); + rc = 7; + /* trailing IAC SE will be eaten separately, as 2-byte NOP */ goto update_and_return; } - memset(&ws, 0, sizeof(ws)); - ws.ws_col = (buf[3] << 8) | buf[4]; - ws.ws_row = (buf[5] << 8) | buf[6]; - ioctl(ts->ptyfd, TIOCSWINSZ, (char *)&ws); - rc = 9; - goto update_and_return; + /* else: other subnegs not supported yet */ } - /* Skip 3-byte cmds (assume they are WILL/WONT/DO/DONT 251..254 codes) */ + /* Assume it is a 3-byte WILL/WONT/DO/DONT 251..254 command and skip it */ #if DEBUG fprintf(stderr, "Ignoring IAC %s,%s\n", TELCMD(buf[1]), TELOPT(buf[2])); |