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036dbb9d9

Denys Vlasenko

2010-10-29

FAILED Duration: 277s

Subject

telnet: convert CR NUL -> CR on input. Closes bug 2569

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

networking/telnet.c +63 -69

networking/telnet.c+63 -69

@@ -42,11 +42,13 @@ enum {
	UF_ECHO = 0x01,
	UF_SGA = 0x02,

-	TS_0 = 1,
+	TS_NORMAL = 0,
+	TS_COPY = 1,
	TS_IAC = 2,
	TS_OPT = 3,
	TS_SUB1 = 4,
	TS_SUB2 = 5,
+	TS_CR = 6,
	};

	typedef unsigned char byte;
@@ -83,13 +85,13 @@ struct globals {
	}; \
	} while (0)

-	/* Function prototypes */
+
	static void rawmode(void);
	static void cookmode(void);
	static void do_linemode(void);
	static void will_charmode(void);
	static void telopt(byte c);
-	static int subneg(byte c);
+	static void subneg(byte c);

	static void iac_flush(void)
	{
@@ -170,24 +172,24 @@ static void handle_net_output(int len)
	* So I implemented it. It's really useful for me. I hope that
	* other people will find it interesting too.
	*/
-
-	int i, j;
+	byte outbuf[2 * DATABUFSIZE];
	byte p = (byte)G.buf;
-	byte outbuf[4*DATABUFSIZE];
+	int j = 0;

-	for (i = len, j = 0; i > 0; i--, p++) {
-	if (*p == 0x1d) {
+	for (; len > 0; len--, p++) {
+	byte c = *p;
+	if (c == 0x1d) {
	con_escape();
	return;
	}
-	outbuf[j++] = *p;
-	if (*p == 0xff)
-	outbuf[j++] = 0xff;
-	else if (*p == 0x0d)
-	outbuf[j++] = 0x00;
+	outbuf[j++] = c;
+	if (c == IAC)
+	outbuf[j++] = c; /* IAC -> IAC IAC */
+	else if (c == '\r')
+	outbuf[j++] = '\0'; /* CR -> CR NUL */
	}
	if (j > 0)
-	write(netfd, outbuf, j);
+	full_write(netfd, outbuf, j);
	}

	static void handle_net_input(int len)
@@ -198,25 +200,44 @@ static void handle_net_input(int len)
	for (i = 0; i < len; i++) {
	byte c = G.buf[i];

-	if (G.telstate == 0) { /* most of the time state == 0 */
+	if (G.telstate == TS_NORMAL) { /* most typical state */
	if (c == IAC) {
	cstart = i;
	G.telstate = TS_IAC;
	}
+	else if (c == '\r') {
+	cstart = i + 1;
+	G.telstate = TS_CR;
+	}
+	/* No IACs were seen so far, no need to copy
+	* bytes within G.buf: */
	continue;
	}
+
	switch (G.telstate) {
-	case TS_0:
+	case TS_CR:
+	/* Prev char was CR. If cur one is NUL, ignore it.
+	* See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
+	*/
+	G.telstate = TS_COPY;
+	if (c == '\0')
+	break;
+	/* else: fall through - need to handle CR IAC ... properly */
+
+	case TS_COPY: /* Prev char was ordinary */
+	/* Similar to NORMAL, but in TS_COPY we need to copy bytes */
	if (c == IAC)
	G.telstate = TS_IAC;
	else
	G.buf[cstart++] = c;
+	if (c == '\r')
+	G.telstate = TS_CR;
	break;

-	case TS_IAC:
-	if (c == IAC) { /* IAC IAC -> 0xFF */
+	case TS_IAC: /* Prev char was IAC */
+	if (c == IAC) { /* IAC IAC -> one IAC */
	G.buf[cstart++] = c;
-	G.telstate = TS_0;
+	G.telstate = TS_COPY;
	break;
	}
	/* else */
@@ -228,34 +249,38 @@ static void handle_net_input(int len)
	case DONT:
	case WILL:
	case WONT:
-	G.telwish = c;
+	G.telwish = c;
	G.telstate = TS_OPT;
	break;
+	/* DATA MARK must be added later */
	default:
-	G.telstate = TS_0; /* DATA MARK must be added later */
+	G.telstate = TS_COPY;
	}
	break;
-	case TS_OPT: /* WILL, WONT, DO, DONT */
+
+	case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
	telopt(c);
-	G.telstate = TS_0;
+	G.telstate = TS_COPY;
	break;
+
	case TS_SUB1: /* Subnegotiation */
	case TS_SUB2: /* Subnegotiation */
-	if (subneg(c))
-	G.telstate = TS_0;
+	subneg(c); /* can change G.telstate */
	break;
	}
	}
-	if (G.telstate) {
+
+	if (G.telstate != TS_NORMAL) {
+	/* We had some IACs, or CR */
	if (G.iaclen)
	iac_flush();
-	if (G.telstate == TS_0)
-	G.telstate = 0;
+	if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
+	G.telstate = TS_NORMAL;
	len = cstart;
	}

	if (len)
-	write(STDOUT_FILENO, G.buf, len);
+	full_write(STDOUT_FILENO, G.buf, len);
	}

	static void put_iac(int c)
@@ -495,7 +520,7 @@ static void telopt(byte c)
	}

	/* subnegotiation -- ignore all (except TTYPE,NAWS) */
-	static int subneg(byte c)
+	static void subneg(byte c)
	{
	switch (G.telstate) {
	case TS_SUB1:
@@ -513,12 +538,13 @@ static int subneg(byte c)
	#endif
	break;
	case TS_SUB2:
-	if (c == SE)
-	return TRUE;
+	if (c == SE) {
+	G.telstate = TS_COPY;
+	return;
+	}
	G.telstate = TS_SUB1;
-	/* break; */
+	break;
	}
-	return FALSE;
	}

	static void rawmode(void)
@@ -533,21 +559,13 @@ static void cookmode(void)
	tcsetattr(0, TCSADRAIN, &G.termios_def);
	}

-	/* poll gives smaller (-70 bytes) code */
-	#define USE_POLL 1
-
	int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int telnet_main(int argc UNUSED_PARAM, char **argv)
	{
	char *host;
	int port;
	int len;
-	#ifdef USE_POLL
	struct pollfd ufds[2];
-	#else
-	fd_set readfds;
-	int maxfd;
-	#endif

	INIT_G();

@@ -585,25 +603,11 @@ int telnet_main(int argc UNUSED_PARAM, char **argv)

	signal(SIGINT, record_signo);

-	#ifdef USE_POLL
	ufds[0].fd = 0; ufds[1].fd = netfd;
	ufds[0].events = ufds[1].events = POLLIN;
-	#else
-	FD_ZERO(&readfds);
-	FD_SET(STDIN_FILENO, &readfds);
-	FD_SET(netfd, &readfds);
-	maxfd = netfd + 1;
-	#endif

	while (1) {
-	#ifndef USE_POLL
-	fd_set rfds = readfds;
-
-	switch (select(maxfd, &rfds, NULL, NULL, NULL))
-	#else
-	switch (poll(ufds, 2, -1))
-	#endif
-	{
+	switch (poll(ufds, 2, -1)) {
	case 0:
	/* timeout */
	case -1:
@@ -615,12 +619,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv)
	break;
	default:

-	#ifdef USE_POLL
-	if (ufds[0].revents)
-	#else
-	if (FD_ISSET(STDIN_FILENO, &rfds))
-	#endif
-	{
+	if (ufds[0].revents) {
	len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
	if (len <= 0)
	doexit(EXIT_SUCCESS);
@@ -628,12 +627,7 @@ int telnet_main(int argc UNUSED_PARAM, char **argv)
	handle_net_output(len);
	}

-	#ifdef USE_POLL
-	if (ufds[1].revents)
-	#else
-	if (FD_ISSET(netfd, &rfds))
-	#endif
-	{
+	if (ufds[1].revents) {
	len = safe_read(netfd, G.buf, DATABUFSIZE);
	if (len <= 0) {
	full_write1_str("Connection closed by foreign host\r\n");