[u/mdw/putty] / ssh.c

#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>

#include "putty.h"

#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif

#include "ssh.h"

#define SSH_MSG_DISCONNECT 1
#define SSH_SMSG_PUBLIC_KEY 2
#define SSH_CMSG_SESSION_KEY 3
#define SSH_CMSG_USER 4
#define SSH_CMSG_AUTH_PASSWORD 9
#define SSH_CMSG_REQUEST_PTY 10
#define SSH_CMSG_EXEC_SHELL 12
#define SSH_CMSG_STDIN_DATA 16
#define SSH_SMSG_STDOUT_DATA 17
#define SSH_SMSG_STDERR_DATA 18
#define SSH_SMSG_SUCCESS 14
#define SSH_SMSG_FAILURE 15
#define SSH_SMSG_EXITSTATUS 20
#define SSH_MSG_IGNORE 32
#define SSH_CMSG_EXIT_CONFIRMATION 33
#define SSH_MSG_DEBUG 36
#define SSH_CMSG_AUTH_TIS 39
#define SSH_SMSG_AUTH_TIS_CHALLENGE 40
#define SSH_CMSG_AUTH_TIS_RESPONSE 41

#define SSH_AUTH_TIS              5

/* Coroutine mechanics for the sillier bits of the code */
#define crBegin1	static int crLine = 0;
#define crBegin2	switch(crLine) { case 0:;
#define crBegin		crBegin1; crBegin2;
#define crFinish(z)	} crLine = 0; return (z)
#define crFinishV	} crLine = 0; return
#define crReturn(z)	\
	do {\
	    crLine=__LINE__; return (z); case __LINE__:;\
	} while (0)
#define crReturnV	\
	do {\
	    crLine=__LINE__; return; case __LINE__:;\
	} while (0)
#define crStop(z)	do{ crLine = 0; return (z); }while(0)
#define crStopV		do{ crLine = 0; return; }while(0)

#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif

static SOCKET s = INVALID_SOCKET;

static unsigned char session_key[32];
static struct ssh_cipher *cipher = NULL;

static char *savedhost;

static enum {
    SSH_STATE_BEFORE_SIZE,
    SSH_STATE_INTERMED,
    SSH_STATE_SESSION,
    SSH_STATE_CLOSED
} ssh_state = SSH_STATE_BEFORE_SIZE;

static int size_needed = FALSE;

static void s_write (char *buf, int len) {
    while (len > 0) {
	int i = send (s, buf, len, 0);
	if (i > 0)
	    len -= i, buf += i;
    }
}

static int s_read (char *buf, int len) {
    int ret = 0;
    while (len > 0) {
	int i = recv (s, buf, len, 0);
	if (i > 0)
	    len -= i, buf += i, ret += i;
	else
	    return i;
    }
    return ret;
}

static void c_write (char *buf, int len) {
    while (len--) {
	int new_head = (inbuf_head + 1) & INBUF_MASK;
	if (new_head != inbuf_reap) {
	    inbuf[inbuf_head] = *buf++;
	    inbuf_head = new_head;
	}
    }
}

struct Packet {
    long length;
    int type;
    unsigned long crc;
    unsigned char *data;
    unsigned char *body;
    long maxlen;
};

static struct Packet pktin = { 0, 0, 0, NULL, 0 };
static struct Packet pktout = { 0, 0, 0, NULL, 0 };

static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
static void ssh_size(void);

static void ssh_gotdata(unsigned char *data, int datalen) {
    static long len, biglen, to_read;
    static unsigned char *p;
    static int i, pad;

    crBegin;
    while (1) {
	for (i = len = 0; i < 4; i++) {
	    while (datalen == 0)
		crReturnV;
	    len = (len << 8) + *data;
	    data++, datalen--;
	}

#ifdef FWHACK
        if (len == 0x52656d6f) {       /* "Remo"te server has closed ... */
            len = 0x300;               /* big enough to carry to end */
        }
#endif

	pad = 8 - (len%8);

	biglen = len + pad;

	len -= 5;		       /* type and CRC */

	pktin.length = len;
	if (pktin.maxlen < biglen) {
	    pktin.maxlen = biglen;
	    pktin.data = (pktin.data == NULL ? malloc(biglen) :
			realloc(pktin.data, biglen));
	    if (!pktin.data)
		fatalbox("Out of memory");
	}

	p = pktin.data, to_read = biglen;
	while (to_read > 0) {
	    static int chunk;
	    chunk = to_read;
	    while (datalen == 0)
		crReturnV;
	    if (chunk > datalen)
		chunk = datalen;
	    memcpy(p, data, chunk);
	    data += chunk;
	    datalen -= chunk;
	    p += chunk;
	    to_read -= chunk;
	}

	if (cipher)
	    cipher->decrypt(pktin.data, biglen);

	pktin.type = pktin.data[pad];
	pktin.body = pktin.data+pad+1;

	if (pktin.type == SSH_MSG_DEBUG) {
	    /* FIXME: log it */
	} else if (pktin.type == SSH_MSG_IGNORE) {
	    /* do nothing */;
	} else
	    ssh_protocol(NULL, 0, 1);
    }
    crFinishV;
}

static void s_wrpkt_start(int type, int len) {
    int pad, biglen;

    len += 5;			       /* type and CRC */
    pad = 8 - (len%8);
    biglen = len + pad;

    pktout.length = len-5;
    if (pktout.maxlen < biglen) {
	pktout.maxlen = biglen;
	pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
		       realloc(pktout.data, biglen+4));
	if (!pktout.data)
	    fatalbox("Out of memory");
    }

    pktout.type = type;
    pktout.body = pktout.data+4+pad+1;
}

static void s_wrpkt(void) {
    int pad, len, biglen, i;
    unsigned long crc;

    len = pktout.length + 5;	       /* type and CRC */
    pad = 8 - (len%8);
    biglen = len + pad;

    pktout.body[-1] = pktout.type;
    for (i=0; i<pad; i++)
	pktout.data[i+4] = random_byte();
    crc = crc32(pktout.data+4, biglen-4);

    pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
    pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
    pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
    pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);

    pktout.data[0] = (len >> 24) & 0xFF;
    pktout.data[1] = (len >> 16) & 0xFF;
    pktout.data[2] = (len >> 8) & 0xFF;
    pktout.data[3] = len & 0xFF;

    if (cipher)
	cipher->encrypt(pktout.data+4, biglen);

    s_write(pktout.data, biglen+4);
}

static int ssh_versioncmp(char *a, char *b) {
    char *ae, *be;
    unsigned long av, bv;

    av = strtoul(a, &ae, 10);
    bv = strtoul(b, &be, 10);
    if (av != bv) return (av < bv ? -1 : +1);
    if (*ae == '.') ae++;
    if (*be == '.') be++;
    av = strtoul(ae, &ae, 10);
    bv = strtoul(be, &be, 10);
    if (av != bv) return (av < bv ? -1 : +1);
    return 0;
}

static int do_ssh_init(void) {
    char c;
    char version[10];
    char vstring[40];
    int i;

#ifdef FWHACK
    i = 0;
    while (s_read(&c, 1) == 1) {
	if (c == 'S' && i < 2) i++;
	else if (c == 'S' && i == 2) i = 2;
	else if (c == 'H' && i == 2) break;
	else i = 0;
    }
#else
    if (s_read(&c,1) != 1 || c != 'S') return 0;
    if (s_read(&c,1) != 1 || c != 'S') return 0;
    if (s_read(&c,1) != 1 || c != 'H') return 0;
#endif
    if (s_read(&c,1) != 1 || c != '-') return 0;
    i = 0;
    while (1) {
	if (s_read(&c,1) != 1)
	    return 0;
	if (i >= 0) {
	    if (c == '-') {
		version[i] = '\0';
		i = -1;
	    } else if (i < sizeof(version)-1)
		version[i++] = c;
	}
	else if (c == '\n')
	    break;
    }

    sprintf(vstring, "SSH-%s-PuTTY\n",
	    (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
    s_write(vstring, strlen(vstring));
    return 1;
}

static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
    int i, j, len;
    unsigned char session_id[16];
    unsigned char *rsabuf, *keystr1, *keystr2;
    unsigned char cookie[8];
    struct RSAKey servkey, hostkey;
    struct MD5Context md5c;
    static unsigned long supported_ciphers_mask, supported_auths_mask;
    int cipher_type;

    extern struct ssh_cipher ssh_3des;
    extern struct ssh_cipher ssh_des;
    extern struct ssh_cipher ssh_blowfish;

    crBegin;

    random_init();

    while (!ispkt)
	crReturnV;

    if (pktin.type != SSH_SMSG_PUBLIC_KEY)
	fatalbox("Public key packet not received");

    memcpy(cookie, pktin.body, 8);

    MD5Init(&md5c);

    i = makekey(pktin.body+8, &servkey, &keystr1);

    j = makekey(pktin.body+8+i, &hostkey, &keystr2);

    supported_ciphers_mask = ((pktin.body[12+i+j] << 24) |
                              (pktin.body[13+i+j] << 16) |
                              (pktin.body[14+i+j] << 8) |
                              (pktin.body[15+i+j]));

    supported_auths_mask = ((pktin.body[16+i+j] << 24) |
                            (pktin.body[17+i+j] << 16) |
                            (pktin.body[18+i+j] << 8) |
                            (pktin.body[19+i+j]));

    MD5Update(&md5c, keystr2, hostkey.bytes);
    MD5Update(&md5c, keystr1, servkey.bytes);
    MD5Update(&md5c, pktin.body, 8);

    MD5Final(session_id, &md5c);

    for (i=0; i<32; i++)
	session_key[i] = random_byte();

    len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);

    rsabuf = malloc(len);
    if (!rsabuf)
	fatalbox("Out of memory");

    verify_ssh_host_key(savedhost, &hostkey);

    for (i=0; i<32; i++) {
	rsabuf[i] = session_key[i];
	if (i < 16)
	    rsabuf[i] ^= session_id[i];
    }

    if (hostkey.bytes > servkey.bytes) {
	rsaencrypt(rsabuf, 32, &servkey);
	rsaencrypt(rsabuf, servkey.bytes, &hostkey);
    } else {
	rsaencrypt(rsabuf, 32, &hostkey);
	rsaencrypt(rsabuf, hostkey.bytes, &servkey);
    }

    cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
                  cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES : 
                  SSH_CIPHER_3DES;
    if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
	c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
	cipher_type = SSH_CIPHER_3DES;
    }

    s_wrpkt_start(SSH_CMSG_SESSION_KEY, len+15);
    pktout.body[0] = cipher_type;
    memcpy(pktout.body+1, cookie, 8);
    pktout.body[9] = (len*8) >> 8;
    pktout.body[10] = (len*8) & 0xFF;
    memcpy(pktout.body+11, rsabuf, len);
    pktout.body[len+11] = pktout.body[len+12] = 0;   /* protocol flags */
    pktout.body[len+13] = pktout.body[len+14] = 0;
    s_wrpkt();

    free(rsabuf);

    cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
             cipher_type == SSH_CIPHER_DES ? &ssh_des :
             &ssh_3des;
    cipher->sesskey(session_key);

    do { crReturnV; } while (!ispkt);

    if (pktin.type != SSH_SMSG_SUCCESS)
	fatalbox("Encryption not successfully enabled");

    fflush(stdout);
    {
	static char username[100];
	static int pos = 0;
	static char c;
	if (!*cfg.username) {
	    c_write("login as: ", 10);
	    while (pos >= 0) {
		do { crReturnV; } while (ispkt);
		while (inlen--) switch (c = *in++) {
		  case 10: case 13:
		    username[pos] = 0;
		    pos = -1;
		    break;
		  case 8: case 127:
		    if (pos > 0) {
			c_write("\b \b", 3);
			pos--;
		    }
		    break;
		  case 21: case 27:
		    while (pos > 0) {
			c_write("\b \b", 3);
			pos--;
		    }
		    break;
		  case 3: case 4:
		    random_save_seed();
		    exit(0);
		    break;
		  default:
		    if (c >= ' ' && c <= '~' && pos < 40) {
			username[pos++] = c;
			c_write(&c, 1);
		    }
		    break;
		}
	    }
	    c_write("\r\n", 2);
	    username[strcspn(username, "\n\r")] = '\0';
	} else {
	    char stuff[200];
	    strncpy(username, cfg.username, 99);
	    username[99] = '\0';
	    sprintf(stuff, "Sent username \"%s\".\r\n", username);
	    c_write(stuff, strlen(stuff));
	}
	s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
	pktout.body[3] = strlen(username);
	memcpy(pktout.body+4, username, strlen(username));
	s_wrpkt();
    }

    do { crReturnV; } while (!ispkt);

    while (pktin.type == SSH_SMSG_FAILURE) {
	static char password[100];
	static int pos;
	static char c;
        static int pwpkt_type;

        /*
         * Show password prompt, having first obtained it via a TIS
         * exchange if we're doing TIS authentication.
         */
        pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
        if (pktin.type == SSH_SMSG_FAILURE &&
            cfg.try_tis_auth &&
            (supported_auths_mask & (1<<SSH_AUTH_TIS))) {
            pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
            s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
            s_wrpkt();
            do { crReturnV; } while (!ispkt);
            if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
                c_write("TIS authentication refused.\r\n", 29);
            } else {
                int challengelen = ((pktin.body[0] << 24) |
                                    (pktin.body[1] << 16) |
                                    (pktin.body[2] << 8) |
                                    (pktin.body[3]));
                c_write(pktin.body+4, challengelen);
            }
        }
        if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
            c_write("password: ", 10);

	pos = 0;
	while (pos >= 0) {
	    do { crReturnV; } while (ispkt);
	    while (inlen--) switch (c = *in++) {
	      case 10: case 13:
		password[pos] = 0;
		pos = -1;
		break;
	      case 8: case 127:
		if (pos > 0)
		    pos--;
		break;
	      case 21: case 27:
		pos = 0;
		break;
	      case 3: case 4:
		random_save_seed();
		exit(0);
		break;
	      default:
		if (c >= ' ' && c <= '~' && pos < 40)
		    password[pos++] = c;
		break;
	    }
	}
	c_write("\r\n", 2);
	s_wrpkt_start(pwpkt_type, 4+strlen(password));
	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
	pktout.body[3] = strlen(password);
	memcpy(pktout.body+4, password, strlen(password));
	s_wrpkt();
	memset(password, 0, strlen(password));
	do { crReturnV; } while (!ispkt);
	if (pktin.type == 15) {
	    c_write("Access denied\r\n", 15);
	} else if (pktin.type != 14) {
	    fatalbox("Strange packet received, type %d", pktin.type);
	}
    }

    if (!cfg.nopty) {
        i = strlen(cfg.termtype);
        s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
        pktout.body[0] = (i >> 24) & 0xFF;
        pktout.body[1] = (i >> 16) & 0xFF;
        pktout.body[2] = (i >> 8) & 0xFF;
        pktout.body[3] = i & 0xFF;
        memcpy(pktout.body+4, cfg.termtype, i);
        i += 4;
        pktout.body[i++] = (rows >> 24) & 0xFF;
        pktout.body[i++] = (rows >> 16) & 0xFF;
        pktout.body[i++] = (rows >> 8) & 0xFF;
        pktout.body[i++] = rows & 0xFF;
        pktout.body[i++] = (cols >> 24) & 0xFF;
        pktout.body[i++] = (cols >> 16) & 0xFF;
        pktout.body[i++] = (cols >> 8) & 0xFF;
        pktout.body[i++] = cols & 0xFF;
        memset(pktout.body+i, 0, 9);       /* 0 pixwidth, 0 pixheight, 0.b endofopt */
        s_wrpkt();
        ssh_state = SSH_STATE_INTERMED;
        do { crReturnV; } while (!ispkt);
        if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
            fatalbox("Protocol confusion");
        } else if (pktin.type == SSH_SMSG_FAILURE) {
            c_write("Server refused to allocate pty\r\n", 32);
        }
    }

    s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
    s_wrpkt();

    ssh_state = SSH_STATE_SESSION;
    if (size_needed)
	ssh_size();

    while (1) {
	crReturnV;
	if (ispkt) {
	    if (pktin.type == SSH_SMSG_STDOUT_DATA ||
                pktin.type == SSH_SMSG_STDERR_DATA) {
		long len = 0;
		for (i = 0; i < 4; i++)
		    len = (len << 8) + pktin.body[i];
		c_write(pktin.body+4, len);
	    } else if (pktin.type == SSH_MSG_DISCONNECT) {
                ssh_state = SSH_STATE_CLOSED;
	    } else if (pktin.type == SSH_SMSG_SUCCESS) {
		/* may be from EXEC_SHELL on some servers */
	    } else if (pktin.type == SSH_SMSG_FAILURE) {
		/* may be from EXEC_SHELL on some servers
		 * if no pty is available or in other odd cases. Ignore */
	    } else if (pktin.type == SSH_SMSG_EXITSTATUS) {
		s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
		s_wrpkt();
	    } else {
		fatalbox("Strange packet received: type %d", pktin.type);
	    }
	} else {
	    s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
	    pktout.body[0] = (inlen >> 24) & 0xFF;
	    pktout.body[1] = (inlen >> 16) & 0xFF;
	    pktout.body[2] = (inlen >> 8) & 0xFF;
	    pktout.body[3] = inlen & 0xFF;
	    memcpy(pktout.body+4, in, inlen);
	    s_wrpkt();
	}
    }

    crFinishV;
}

/*
 * Called to set up the connection. Will arrange for WM_NETEVENT
 * messages to be passed to the specified window, whose window
 * procedure should then call telnet_msg().
 *
 * Returns an error message, or NULL on success.
 *
 * Also places the canonical host name into `realhost'.
 */
static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
    SOCKADDR_IN addr;
    struct hostent *h;
    unsigned long a;
#ifdef FWHACK
    char *FWhost;
    int FWport;
#endif

    savedhost = malloc(1+strlen(host));
    if (!savedhost)
	fatalbox("Out of memory");
    strcpy(savedhost, host);

#ifdef FWHACK
    FWhost = host;
    FWport = port;
    host = FWSTR;
    port = 23;
#endif

    /*
     * Try to find host.
     */
    if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
	if ( (h = gethostbyname(host)) == NULL)
	    switch (WSAGetLastError()) {
	      case WSAENETDOWN: return "Network is down";
	      case WSAHOST_NOT_FOUND: case WSANO_DATA:
		return "Host does not exist";
	      case WSATRY_AGAIN: return "Host not found";
	      default: return "gethostbyname: unknown error";
	    }
	memcpy (&a, h->h_addr, sizeof(a));
	*realhost = h->h_name;
    } else
	*realhost = host;
#ifdef FWHACK
    *realhost = FWhost;
#endif
    a = ntohl(a);

    if (port < 0)
	port = 22;		       /* default ssh port */

    /*
     * Open socket.
     */
    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s == INVALID_SOCKET)
	switch (WSAGetLastError()) {
	  case WSAENETDOWN: return "Network is down";
	  case WSAEAFNOSUPPORT: return "TCP/IP support not present";
	  default: return "socket(): unknown error";
	}

    /*
     * Bind to local address.
     */
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    addr.sin_port = htons(0);
    if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
	switch (WSAGetLastError()) {
	  case WSAENETDOWN: return "Network is down";
	  default: return "bind(): unknown error";
	}

    /*
     * Connect to remote address.
     */
    addr.sin_addr.s_addr = htonl(a);
    addr.sin_port = htons((short)port);
    if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
	switch (WSAGetLastError()) {
	  case WSAENETDOWN: return "Network is down";
	  case WSAECONNREFUSED: return "Connection refused";
	  case WSAENETUNREACH: return "Network is unreachable";
	  case WSAEHOSTUNREACH: return "No route to host";
	  default: return "connect(): unknown error";
	}

#ifdef FWHACK
    send(s, "connect ", 8, 0);
    send(s, FWhost, strlen(FWhost), 0);
    {
	char buf[20];
	sprintf(buf, " %d\n", FWport);
	send (s, buf, strlen(buf), 0);
    }
#endif

    if (!do_ssh_init())
	return "Protocol initialisation error";

    if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
	switch (WSAGetLastError()) {
	  case WSAENETDOWN: return "Network is down";
	  default: return "WSAAsyncSelect(): unknown error";
	}

    return NULL;
}

/*
 * Process a WM_NETEVENT message. Will return 0 if the connection
 * has closed, or <0 for a socket error.
 */
static int ssh_msg (WPARAM wParam, LPARAM lParam) {
    int ret;
    char buf[256];

    if (s == INVALID_SOCKET)	       /* how the hell did we get here?! */
	return -5000;

    if (WSAGETSELECTERROR(lParam) != 0)
	return -WSAGETSELECTERROR(lParam);

    switch (WSAGETSELECTEVENT(lParam)) {
      case FD_READ:
	ret = recv(s, buf, sizeof(buf), 0);
	if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
	    return 1;
	if (ret < 0)		       /* any _other_ error */
	    return -10000-WSAGetLastError();
	if (ret == 0) {
	    s = INVALID_SOCKET;
	    return 0;		       /* can't happen, in theory */
	}
	ssh_gotdata (buf, ret);
	return 1;
      case FD_CLOSE:
	s = INVALID_SOCKET;
        ssh_state = SSH_STATE_CLOSED;
	return 0;
    }
    return 1;			       /* shouldn't happen, but WTF */
}

/*
 * Called to send data down the Telnet connection.
 */
static void ssh_send (char *buf, int len) {
    if (s == INVALID_SOCKET)
	return;

    ssh_protocol(buf, len, 0);
}

/*
 * Called to set the size of the window from Telnet's POV.
 */
static void ssh_size(void) {
    switch (ssh_state) {
      case SSH_STATE_BEFORE_SIZE:
      case SSH_STATE_CLOSED:
	break;			       /* do nothing */
      case SSH_STATE_INTERMED:
	size_needed = TRUE;	       /* buffer for later */
	break;
      case SSH_STATE_SESSION:
        if (!cfg.nopty) {
            s_wrpkt_start(11, 16);
            pktout.body[0] = (rows >> 24) & 0xFF;
            pktout.body[1] = (rows >> 16) & 0xFF;
            pktout.body[2] = (rows >> 8) & 0xFF;
            pktout.body[3] = rows & 0xFF;
            pktout.body[4] = (cols >> 24) & 0xFF;
            pktout.body[5] = (cols >> 16) & 0xFF;
            pktout.body[6] = (cols >> 8) & 0xFF;
            pktout.body[7] = cols & 0xFF;
            memset(pktout.body+8, 0, 8);
            s_wrpkt();
        }
    }
}

/*
 * (Send Telnet special codes)
 */
static void ssh_special (Telnet_Special code) {
    /* do nothing */
}

Backend ssh_backend = {
    ssh_init,
    ssh_msg,
    ssh_send,
    ssh_size,
    ssh_special
};
Commit	Line	Data
374330e2	1	#include <stdio.h>
	2	#include <stdlib.h>
	3	#include <winsock.h>
	4
	5	#include "putty.h"
	6
	7	#ifndef FALSE
	8	#define FALSE 0
	9	#endif
	10	#ifndef TRUE
	11	#define TRUE 1
	12	#endif
	13
	14	#include "ssh.h"
	15
972a41c8	16	#define SSH_MSG_DISCONNECT 1
	17	#define SSH_SMSG_PUBLIC_KEY 2
	18	#define SSH_CMSG_SESSION_KEY 3
	19	#define SSH_CMSG_USER 4
	20	#define SSH_CMSG_AUTH_PASSWORD 9
	21	#define SSH_CMSG_REQUEST_PTY 10
	22	#define SSH_CMSG_EXEC_SHELL 12
	23	#define SSH_CMSG_STDIN_DATA 16
	24	#define SSH_SMSG_STDOUT_DATA 17
	25	#define SSH_SMSG_STDERR_DATA 18
	26	#define SSH_SMSG_SUCCESS 14
	27	#define SSH_SMSG_FAILURE 15
	28	#define SSH_SMSG_EXITSTATUS 20
	29	#define SSH_MSG_IGNORE 32
	30	#define SSH_CMSG_EXIT_CONFIRMATION 33
	31	#define SSH_MSG_DEBUG 36
ccbfb941	32	#define SSH_CMSG_AUTH_TIS 39
	33	#define SSH_SMSG_AUTH_TIS_CHALLENGE 40
	34	#define SSH_CMSG_AUTH_TIS_RESPONSE 41
	35
	36	#define SSH_AUTH_TIS 5
972a41c8	37
374330e2	38	/* Coroutine mechanics for the sillier bits of the code */
	39	#define crBegin1 static int crLine = 0;
	40	#define crBegin2 switch(crLine) { case 0:;
	41	#define crBegin crBegin1; crBegin2;
	42	#define crFinish(z) } crLine = 0; return (z)
	43	#define crFinishV } crLine = 0; return
	44	#define crReturn(z) \
	45	do {\
	46	crLine=__LINE__; return (z); case __LINE__:;\
	47	} while (0)
	48	#define crReturnV \
	49	do {\
	50	crLine=__LINE__; return; case __LINE__:;\
	51	} while (0)
	52	#define crStop(z) do{ crLine = 0; return (z); }while(0)
	53	#define crStopV do{ crLine = 0; return; }while(0)
	54
	55	#ifndef FALSE
	56	#define FALSE 0
	57	#endif
	58	#ifndef TRUE
	59	#define TRUE 1
	60	#endif
	61
	62	static SOCKET s = INVALID_SOCKET;
	63
	64	static unsigned char session_key[32];
	65	static struct ssh_cipher *cipher = NULL;
	66
	67	static char *savedhost;
	68
	69	static enum {
	70	SSH_STATE_BEFORE_SIZE,
	71	SSH_STATE_INTERMED,
21248260	72	SSH_STATE_SESSION,
21248260	73	SSH_STATE_CLOSED
374330e2	74	} ssh_state = SSH_STATE_BEFORE_SIZE;
	75
	76	static int size_needed = FALSE;
	77
	78	static void s_write (char *buf, int len) {
	79	while (len > 0) {
	80	int i = send (s, buf, len, 0);
	81	if (i > 0)
	82	len -= i, buf += i;
	83	}
	84	}
	85
	86	static int s_read (char *buf, int len) {
	87	int ret = 0;
	88	while (len > 0) {
	89	int i = recv (s, buf, len, 0);
	90	if (i > 0)
	91	len -= i, buf += i, ret += i;
	92	else
	93	return i;
	94	}
	95	return ret;
	96	}
	97
	98	static void c_write (char *buf, int len) {
	99	while (len--) {
	100	int new_head = (inbuf_head + 1) & INBUF_MASK;
374330e2	101	if (new_head != inbuf_reap) {
	102	inbuf[inbuf_head] = *buf++;
	103	inbuf_head = new_head;
	104	}
	105	}
	106	}
	107
	108	struct Packet {
	109	long length;
	110	int type;
	111	unsigned long crc;
	112	unsigned char *data;
	113	unsigned char *body;
	114	long maxlen;
	115	};
	116
	117	static struct Packet pktin = { 0, 0, 0, NULL, 0 };
	118	static struct Packet pktout = { 0, 0, 0, NULL, 0 };
	119
	120	static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
	121	static void ssh_size(void);
	122
	123	static void ssh_gotdata(unsigned char *data, int datalen) {
	124	static long len, biglen, to_read;
f67b4e85	125	static unsigned char *p;
374330e2	126	static int i, pad;
374330e2	127
	128	crBegin;
	129	while (1) {
	130	for (i = len = 0; i < 4; i++) {
	131	while (datalen == 0)
	132	crReturnV;
	133	len = (len << 8) + *data;
	134	data++, datalen--;
	135	}
	136
37508af4	137	#ifdef FWHACK
	138	if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
	139	len = 0x300; /* big enough to carry to end */
	140	}
	141	#endif
	142
374330e2	143	pad = 8 - (len%8);
	144
	145	biglen = len + pad;
	146
	147	len -= 5; /* type and CRC */
	148
	149	pktin.length = len;
	150	if (pktin.maxlen < biglen) {
	151	pktin.maxlen = biglen;
	152	pktin.data = (pktin.data == NULL ? malloc(biglen) :
	153	realloc(pktin.data, biglen));
	154	if (!pktin.data)
	155	fatalbox("Out of memory");
	156	}
	157
	158	p = pktin.data, to_read = biglen;
	159	while (to_read > 0) {
	160	static int chunk;
	161	chunk = to_read;
	162	while (datalen == 0)
	163	crReturnV;
	164	if (chunk > datalen)
	165	chunk = datalen;
	166	memcpy(p, data, chunk);
	167	data += chunk;
	168	datalen -= chunk;
	169	p += chunk;
	170	to_read -= chunk;
	171	}
	172
	173	if (cipher)
	174	cipher->decrypt(pktin.data, biglen);
	175
	176	pktin.type = pktin.data[pad];
	177	pktin.body = pktin.data+pad+1;
	178
972a41c8	179	if (pktin.type == SSH_MSG_DEBUG) {
374330e2	180	/* FIXME: log it */
972a41c8	181	} else if (pktin.type == SSH_MSG_IGNORE) {
96b9dc0a	182	/* do nothing */;
374330e2	183	} else
	184	ssh_protocol(NULL, 0, 1);
	185	}
	186	crFinishV;
	187	}
	188
	189	static void s_wrpkt_start(int type, int len) {
	190	int pad, biglen;
	191
	192	len += 5; /* type and CRC */
	193	pad = 8 - (len%8);
	194	biglen = len + pad;
	195
	196	pktout.length = len-5;
	197	if (pktout.maxlen < biglen) {
	198	pktout.maxlen = biglen;
c1f5f956	199	pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
c1f5f956	200	realloc(pktout.data, biglen+4));
374330e2	201	if (!pktout.data)
	202	fatalbox("Out of memory");
	203	}
	204
	205	pktout.type = type;
	206	pktout.body = pktout.data+4+pad+1;
	207	}
	208
	209	static void s_wrpkt(void) {
	210	int pad, len, biglen, i;
	211	unsigned long crc;
	212
	213	len = pktout.length + 5; /* type and CRC */
	214	pad = 8 - (len%8);
	215	biglen = len + pad;
	216
	217	pktout.body[-1] = pktout.type;
	218	for (i=0; i<pad; i++)
	219	pktout.data[i+4] = random_byte();
	220	crc = crc32(pktout.data+4, biglen-4);
	221
	222	pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
	223	pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
	224	pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
	225	pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);
	226
	227	pktout.data[0] = (len >> 24) & 0xFF;
	228	pktout.data[1] = (len >> 16) & 0xFF;
	229	pktout.data[2] = (len >> 8) & 0xFF;
	230	pktout.data[3] = len & 0xFF;
	231
	232	if (cipher)
	233	cipher->encrypt(pktout.data+4, biglen);
	234
	235	s_write(pktout.data, biglen+4);
	236	}
	237
9697bfd2	238	static int ssh_versioncmp(char a, char b) {
	239	char ae, be;
	240	unsigned long av, bv;
	241
43aa02a7	242	av = strtoul(a, &ae, 10);
43aa02a7	243	bv = strtoul(b, &be, 10);
9697bfd2	244	if (av != bv) return (av < bv ? -1 : +1);
	245	if (*ae == '.') ae++;
	246	if (*be == '.') be++;
43aa02a7	247	av = strtoul(ae, &ae, 10);
43aa02a7	248	bv = strtoul(be, &be, 10);
9697bfd2	249	if (av != bv) return (av < bv ? -1 : +1);
	250	return 0;
	251	}
	252
374330e2	253	static int do_ssh_init(void) {
	254	char c;
	255	char version[10];
	256	char vstring[40];
	257	int i;
	258
	259	#ifdef FWHACK
	260	i = 0;
	261	while (s_read(&c, 1) == 1) {
	262	if (c == 'S' && i < 2) i++;
	263	else if (c == 'S' && i == 2) i = 2;
	264	else if (c == 'H' && i == 2) break;
	265	else i = 0;
	266	}
	267	#else
	268	if (s_read(&c,1) != 1 \|\| c != 'S') return 0;
	269	if (s_read(&c,1) != 1 \|\| c != 'S') return 0;
	270	if (s_read(&c,1) != 1 \|\| c != 'H') return 0;
	271	#endif
	272	if (s_read(&c,1) != 1 \|\| c != '-') return 0;
	273	i = 0;
	274	while (1) {
	275	if (s_read(&c,1) != 1)
	276	return 0;
	277	if (i >= 0) {
	278	if (c == '-') {
	279	version[i] = '\0';
	280	i = -1;
	281	} else if (i < sizeof(version)-1)
	282	version[i++] = c;
	283	}
	284	else if (c == '\n')
	285	break;
	286	}
	287
9697bfd2	288	sprintf(vstring, "SSH-%s-PuTTY\n",
9697bfd2	289	(ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
374330e2	290	s_write(vstring, strlen(vstring));
fef97f43	291	return 1;
374330e2	292	}
	293
	294	static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
	295	int i, j, len;
	296	unsigned char session_id[16];
	297	unsigned char rsabuf, keystr1, *keystr2;
	298	unsigned char cookie[8];
	299	struct RSAKey servkey, hostkey;
	300	struct MD5Context md5c;
ccbfb941	301	static unsigned long supported_ciphers_mask, supported_auths_mask;
bea1ef5f	302	int cipher_type;
374330e2	303
374330e2	304	extern struct ssh_cipher ssh_3des;
9697bfd2	305	extern struct ssh_cipher ssh_des;
bea1ef5f	306	extern struct ssh_cipher ssh_blowfish;
374330e2	307
	308	crBegin;
	309
	310	random_init();
	311
	312	while (!ispkt)
	313	crReturnV;
	314
972a41c8	315	if (pktin.type != SSH_SMSG_PUBLIC_KEY)
374330e2	316	fatalbox("Public key packet not received");
	317
	318	memcpy(cookie, pktin.body, 8);
	319
	320	MD5Init(&md5c);
	321
	322	i = makekey(pktin.body+8, &servkey, &keystr1);
	323
	324	j = makekey(pktin.body+8+i, &hostkey, &keystr2);
	325
ccbfb941	326	supported_ciphers_mask = ((pktin.body[12+i+j] << 24) \|
	327	(pktin.body[13+i+j] << 16) \|
	328	(pktin.body[14+i+j] << 8) \|
	329	(pktin.body[15+i+j]));
	330
	331	supported_auths_mask = ((pktin.body[16+i+j] << 24) \|
	332	(pktin.body[17+i+j] << 16) \|
	333	(pktin.body[18+i+j] << 8) \|
	334	(pktin.body[19+i+j]));
bea1ef5f	335
374330e2	336	MD5Update(&md5c, keystr2, hostkey.bytes);
	337	MD5Update(&md5c, keystr1, servkey.bytes);
	338	MD5Update(&md5c, pktin.body, 8);
	339
	340	MD5Final(session_id, &md5c);
	341
	342	for (i=0; i<32; i++)
	343	session_key[i] = random_byte();
	344
	345	len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
	346
	347	rsabuf = malloc(len);
	348	if (!rsabuf)
	349	fatalbox("Out of memory");
	350
	351	verify_ssh_host_key(savedhost, &hostkey);
	352
	353	for (i=0; i<32; i++) {
	354	rsabuf[i] = session_key[i];
	355	if (i < 16)
	356	rsabuf[i] ^= session_id[i];
	357	}
	358
	359	if (hostkey.bytes > servkey.bytes) {
	360	rsaencrypt(rsabuf, 32, &servkey);
	361	rsaencrypt(rsabuf, servkey.bytes, &hostkey);
	362	} else {
	363	rsaencrypt(rsabuf, 32, &hostkey);
	364	rsaencrypt(rsabuf, hostkey.bytes, &servkey);
	365	}
	366
bea1ef5f	367	cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
9697bfd2	368	cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
bea1ef5f	369	SSH_CIPHER_3DES;
	370	if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
	371	c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
	372	cipher_type = SSH_CIPHER_3DES;
	373	}
	374
972a41c8	375	s_wrpkt_start(SSH_CMSG_SESSION_KEY, len+15);
bea1ef5f	376	pktout.body[0] = cipher_type;
374330e2	377	memcpy(pktout.body+1, cookie, 8);
	378	pktout.body[9] = (len*8) >> 8;
	379	pktout.body[10] = (len*8) & 0xFF;
	380	memcpy(pktout.body+11, rsabuf, len);
	381	pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
	382	pktout.body[len+13] = pktout.body[len+14] = 0;
	383	s_wrpkt();
	384
	385	free(rsabuf);
	386
bea1ef5f	387	cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
9697bfd2	388	cipher_type == SSH_CIPHER_DES ? &ssh_des :
bea1ef5f	389	&ssh_3des;
374330e2	390	cipher->sesskey(session_key);
	391
	392	do { crReturnV; } while (!ispkt);
	393
972a41c8	394	if (pktin.type != SSH_SMSG_SUCCESS)
374330e2	395	fatalbox("Encryption not successfully enabled");
	396
	397	fflush(stdout);
	398	{
	399	static char username[100];
	400	static int pos = 0;
	401	static char c;
	402	if (!*cfg.username) {
	403	c_write("login as: ", 10);
	404	while (pos >= 0) {
	405	do { crReturnV; } while (ispkt);
	406	while (inlen--) switch (c = *in++) {
	407	case 10: case 13:
	408	username[pos] = 0;
	409	pos = -1;
	410	break;
	411	case 8: case 127:
	412	if (pos > 0) {
	413	c_write("\b \b", 3);
	414	pos--;
	415	}
	416	break;
	417	case 21: case 27:
	418	while (pos > 0) {
	419	c_write("\b \b", 3);
	420	pos--;
	421	}
	422	break;
	423	case 3: case 4:
	424	random_save_seed();
	425	exit(0);
	426	break;
	427	default:
	428	if (c >= ' ' && c <= '~' && pos < 40) {
	429	username[pos++] = c;
	430	c_write(&c, 1);
	431	}
	432	break;
	433	}
	434	}
	435	c_write("\r\n", 2);
	436	username[strcspn(username, "\n\r")] = '\0';
	437	} else {
	438	char stuff[200];
	439	strncpy(username, cfg.username, 99);
	440	username[99] = '\0';
	441	sprintf(stuff, "Sent username \"%s\".\r\n", username);
	442	c_write(stuff, strlen(stuff));
	443	}
972a41c8	444	s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
374330e2	445	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
	446	pktout.body[3] = strlen(username);
	447	memcpy(pktout.body+4, username, strlen(username));
	448	s_wrpkt();
	449	}
	450
	451	do { crReturnV; } while (!ispkt);
	452
972a41c8	453	while (pktin.type == SSH_SMSG_FAILURE) {
374330e2	454	static char password[100];
	455	static int pos;
	456	static char c;
ccbfb941	457	static int pwpkt_type;
	458
	459	/*
	460	* Show password prompt, having first obtained it via a TIS
	461	* exchange if we're doing TIS authentication.
	462	*/
	463	pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
	464	if (pktin.type == SSH_SMSG_FAILURE &&
	465	cfg.try_tis_auth &&
	466	(supported_auths_mask & (1<<SSH_AUTH_TIS))) {
	467	pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
	468	s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
	469	s_wrpkt();
	470	do { crReturnV; } while (!ispkt);
	471	if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
	472	c_write("TIS authentication refused.\r\n", 29);
	473	} else {
	474	int challengelen = ((pktin.body[0] << 24) \|
	475	(pktin.body[1] << 16) \|
	476	(pktin.body[2] << 8) \|
	477	(pktin.body[3]));
	478	c_write(pktin.body+4, challengelen);
	479	}
	480	}
	481	if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
	482	c_write("password: ", 10);
	483
374330e2	484	pos = 0;
	485	while (pos >= 0) {
	486	do { crReturnV; } while (ispkt);
	487	while (inlen--) switch (c = *in++) {
	488	case 10: case 13:
	489	password[pos] = 0;
	490	pos = -1;
	491	break;
	492	case 8: case 127:
	493	if (pos > 0)
	494	pos--;
	495	break;
	496	case 21: case 27:
	497	pos = 0;
	498	break;
	499	case 3: case 4:
	500	random_save_seed();
	501	exit(0);
	502	break;
	503	default:
	504	if (c >= ' ' && c <= '~' && pos < 40)
	505	password[pos++] = c;
	506	break;
	507	}
	508	}
	509	c_write("\r\n", 2);
ccbfb941	510	s_wrpkt_start(pwpkt_type, 4+strlen(password));
374330e2	511	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
	512	pktout.body[3] = strlen(password);
	513	memcpy(pktout.body+4, password, strlen(password));
	514	s_wrpkt();
	515	memset(password, 0, strlen(password));
	516	do { crReturnV; } while (!ispkt);
	517	if (pktin.type == 15) {
	518	c_write("Access denied\r\n", 15);
	519	} else if (pktin.type != 14) {
	520	fatalbox("Strange packet received, type %d", pktin.type);
	521	}
	522	}
	523
fef97f43	524	if (!cfg.nopty) {
fef97f43	525	i = strlen(cfg.termtype);
972a41c8	526	s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
fef97f43	527	pktout.body[0] = (i >> 24) & 0xFF;
	528	pktout.body[1] = (i >> 16) & 0xFF;
	529	pktout.body[2] = (i >> 8) & 0xFF;
	530	pktout.body[3] = i & 0xFF;
	531	memcpy(pktout.body+4, cfg.termtype, i);
	532	i += 4;
	533	pktout.body[i++] = (rows >> 24) & 0xFF;
	534	pktout.body[i++] = (rows >> 16) & 0xFF;
	535	pktout.body[i++] = (rows >> 8) & 0xFF;
	536	pktout.body[i++] = rows & 0xFF;
	537	pktout.body[i++] = (cols >> 24) & 0xFF;
	538	pktout.body[i++] = (cols >> 16) & 0xFF;
	539	pktout.body[i++] = (cols >> 8) & 0xFF;
	540	pktout.body[i++] = cols & 0xFF;
	541	memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
	542	s_wrpkt();
	543	ssh_state = SSH_STATE_INTERMED;
	544	do { crReturnV; } while (!ispkt);
ccbfb941	545	if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
fef97f43	546	fatalbox("Protocol confusion");
ccbfb941	547	} else if (pktin.type == SSH_SMSG_FAILURE) {
fef97f43	548	c_write("Server refused to allocate pty\r\n", 32);
fef97f43	549	}
374330e2	550	}
374330e2	551
972a41c8	552	s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
374330e2	553	s_wrpkt();
	554
	555	ssh_state = SSH_STATE_SESSION;
	556	if (size_needed)
	557	ssh_size();
	558
	559	while (1) {
	560	crReturnV;
	561	if (ispkt) {
972a41c8	562	if (pktin.type == SSH_SMSG_STDOUT_DATA \|\|
972a41c8	563	pktin.type == SSH_SMSG_STDERR_DATA) {
374330e2	564	long len = 0;
	565	for (i = 0; i < 4; i++)
	566	len = (len << 8) + pktin.body[i];
	567	c_write(pktin.body+4, len);
972a41c8	568	} else if (pktin.type == SSH_MSG_DISCONNECT) {
21248260	569	ssh_state = SSH_STATE_CLOSED;
ccbfb941	570	} else if (pktin.type == SSH_SMSG_SUCCESS) {
972a41c8	571	/* may be from EXEC_SHELL on some servers */
ccbfb941	572	} else if (pktin.type == SSH_SMSG_FAILURE) {
972a41c8	573	/* may be from EXEC_SHELL on some servers
374330e2	574	* if no pty is available or in other odd cases. Ignore */
972a41c8	575	} else if (pktin.type == SSH_SMSG_EXITSTATUS) {
972a41c8	576	s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
374330e2	577	s_wrpkt();
	578	} else {
	579	fatalbox("Strange packet received: type %d", pktin.type);
	580	}
	581	} else {
972a41c8	582	s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
374330e2	583	pktout.body[0] = (inlen >> 24) & 0xFF;
	584	pktout.body[1] = (inlen >> 16) & 0xFF;
	585	pktout.body[2] = (inlen >> 8) & 0xFF;
	586	pktout.body[3] = inlen & 0xFF;
	587	memcpy(pktout.body+4, in, inlen);
	588	s_wrpkt();
	589	}
	590	}
	591
	592	crFinishV;
	593	}
	594
	595	/*
	596	* Called to set up the connection. Will arrange for WM_NETEVENT
	597	* messages to be passed to the specified window, whose window
	598	* procedure should then call telnet_msg().
	599	*
	600	* Returns an error message, or NULL on success.
	601	*
	602	* Also places the canonical host name into `realhost'.
	603	*/
	604	static char ssh_init (HWND hwnd, char host, int port, char **realhost) {
	605	SOCKADDR_IN addr;
	606	struct hostent *h;
	607	unsigned long a;
	608	#ifdef FWHACK
	609	char *FWhost;
	610	int FWport;
	611	#endif
	612
	613	savedhost = malloc(1+strlen(host));
	614	if (!savedhost)
	615	fatalbox("Out of memory");
	616	strcpy(savedhost, host);
	617
	618	#ifdef FWHACK
	619	FWhost = host;
	620	FWport = port;
	621	host = FWSTR;
	622	port = 23;
	623	#endif
	624
	625	/*
	626	* Try to find host.
	627	*/
	628	if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
	629	if ( (h = gethostbyname(host)) == NULL)
	630	switch (WSAGetLastError()) {
	631	case WSAENETDOWN: return "Network is down";
	632	case WSAHOST_NOT_FOUND: case WSANO_DATA:
	633	return "Host does not exist";
	634	case WSATRY_AGAIN: return "Host not found";
	635	default: return "gethostbyname: unknown error";
	636	}
	637	memcpy (&a, h->h_addr, sizeof(a));
	638	*realhost = h->h_name;
	639	} else
	640	*realhost = host;
	641	#ifdef FWHACK
	642	*realhost = FWhost;
	643	#endif
	644	a = ntohl(a);
	645
	646	if (port < 0)
647	port = 22; /* default ssh port */
648
649	/*
650	* Open socket.
651	*/
652	s = socket(AF_INET, SOCK_STREAM, 0);
653	if (s == INVALID_SOCKET)
654	switch (WSAGetLastError()) {
655	case WSAENETDOWN: return "Network is down";
656	case WSAEAFNOSUPPORT: return "TCP/IP support not present";
657	default: return "socket(): unknown error";
658	}
659
660	/*
661	* Bind to local address.
662	*/
663	addr.sin_family = AF_INET;
664	addr.sin_addr.s_addr = htonl(INADDR_ANY);
665	addr.sin_port = htons(0);
666	if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
667	switch (WSAGetLastError()) {
668	case WSAENETDOWN: return "Network is down";
669	default: return "bind(): unknown error";
670	}
671
672	/*
673	* Connect to remote address.
674	*/
675	addr.sin_addr.s_addr = htonl(a);
676	addr.sin_port = htons((short)port);
677	if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
678	switch (WSAGetLastError()) {
679	case WSAENETDOWN: return "Network is down";
680	case WSAECONNREFUSED: return "Connection refused";
681	case WSAENETUNREACH: return "Network is unreachable";
682	case WSAEHOSTUNREACH: return "No route to host";
683	default: return "connect(): unknown error";
684	}
685
686	#ifdef FWHACK
687	send(s, "connect ", 8, 0);
688	send(s, FWhost, strlen(FWhost), 0);
689	{
690	char buf[20];
691	sprintf(buf, " %d\n", FWport);
692	send (s, buf, strlen(buf), 0);
693	}
694	#endif
695
696	if (!do_ssh_init())
697	return "Protocol initialisation error";
698
699	if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ \| FD_CLOSE) == SOCKET_ERROR)
700	switch (WSAGetLastError()) {
701	case WSAENETDOWN: return "Network is down";
702	default: return "WSAAsyncSelect(): unknown error";
703	}
704
705	return NULL;
706	}
707
708	/*
709	* Process a WM_NETEVENT message. Will return 0 if the connection
710	* has closed, or <0 for a socket error.
711	*/
712	static int ssh_msg (WPARAM wParam, LPARAM lParam) {
713	int ret;
714	char buf[256];
715
716	if (s == INVALID_SOCKET) /* how the hell did we get here?! */
717	return -5000;
718
719	if (WSAGETSELECTERROR(lParam) != 0)
720	return -WSAGETSELECTERROR(lParam);
721
722	switch (WSAGETSELECTEVENT(lParam)) {
723	case FD_READ:
724	ret = recv(s, buf, sizeof(buf), 0);
725	if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
726	return 1;
727	if (ret < 0) /* any _other_ error */
728	return -10000-WSAGetLastError();
729	if (ret == 0) {
730	s = INVALID_SOCKET;
731	return 0; /* can't happen, in theory */
732	}
733	ssh_gotdata (buf, ret);
734	return 1;
735	case FD_CLOSE:
736	s = INVALID_SOCKET;
21248260	737	ssh_state = SSH_STATE_CLOSED;
374330e2	738	return 0;
	739	}
	740	return 1; /* shouldn't happen, but WTF */
	741	}
	742
	743	/*
	744	* Called to send data down the Telnet connection.
	745	*/
	746	static void ssh_send (char *buf, int len) {
	747	if (s == INVALID_SOCKET)
	748	return;
	749
	750	ssh_protocol(buf, len, 0);
	751	}
	752
	753	/*
	754	* Called to set the size of the window from Telnet's POV.
	755	*/
	756	static void ssh_size(void) {
	757	switch (ssh_state) {
	758	case SSH_STATE_BEFORE_SIZE:
21248260	759	case SSH_STATE_CLOSED:
374330e2	760	break; /* do nothing */
	761	case SSH_STATE_INTERMED:
	762	size_needed = TRUE; /* buffer for later */
	763	break;
	764	case SSH_STATE_SESSION:
fef97f43	765	if (!cfg.nopty) {
	766	s_wrpkt_start(11, 16);
	767	pktout.body[0] = (rows >> 24) & 0xFF;
	768	pktout.body[1] = (rows >> 16) & 0xFF;
	769	pktout.body[2] = (rows >> 8) & 0xFF;
	770	pktout.body[3] = rows & 0xFF;
	771	pktout.body[4] = (cols >> 24) & 0xFF;
	772	pktout.body[5] = (cols >> 16) & 0xFF;
	773	pktout.body[6] = (cols >> 8) & 0xFF;
	774	pktout.body[7] = cols & 0xFF;
	775	memset(pktout.body+8, 0, 8);
	776	s_wrpkt();
	777	}
374330e2	778	}
	779	}
	780
	781	/*
	782	* (Send Telnet special codes)
	783	*/
	784	static void ssh_special (Telnet_Special code) {
	785	/* do nothing */
	786	}
	787
	788	Backend ssh_backend = {
	789	ssh_init,
	790	ssh_msg,
	791	ssh_send,
	792	ssh_size,
	793	ssh_special
	794	};