[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"

/* 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;
	int c = (unsigned char) *buf;
	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 c, *p;
    static int i, pad;
    static char padding[8];
    static unsigned char word[4];

    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 == 36) {	       /* SSH_MSG_DEBUG */
	    /* FIXME: log it */
	} 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 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-7.7.7\n",
	    (strcmp(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;

    extern struct ssh_cipher ssh_3des;

    crBegin;

    random_init();

    while (!ispkt)
	crReturnV;

    if (pktin.type != 2)
	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);

    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);
    }

    s_wrpkt_start(3, len+15);
    pktout.body[0] = 3;		       /* SSH_CIPHER_3DES */
    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 = &ssh_3des;
    cipher->sesskey(session_key);

    do { crReturnV; } while (!ispkt);

    if (pktin.type != 14)
	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(4, 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 == 15) {
	static char password[100];
	static int pos;
	static char c;
	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(9, 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(10, 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 != 14 && pktin.type != 15) {
            fatalbox("Protocol confusion");
        } else if (pktin.type == 15) {
            c_write("Server refused to allocate pty\r\n", 32);
        }
    }

    s_wrpkt_start(12, 0);
    s_wrpkt();

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

    while (1) {
	crReturnV;
	if (ispkt) {
	    if (pktin.type == 17 || pktin.type == 18) {
		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 == 1) {
		/* SSH_MSG_DISCONNECT */
                ssh_state = SSH_STATE_CLOSED;
	    } else if (pktin.type == 14) {
		/* SSH_MSG_SUCCESS: may be from EXEC_SHELL on some servers */
	    } else if (pktin.type == 15) {
		/* SSH_MSG_FAILURE: may be from EXEC_SHELL on some servers
		 * if no pty is available or in other odd cases. Ignore */
	    } else if (pktin.type == 20) {
		/* EXITSTATUS */
		s_wrpkt_start(33, 0);
		s_wrpkt();
	    } else {
		fatalbox("Strange packet received: type %d", pktin.type);
	    }
	} else {
	    s_wrpkt_start(16, 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
	16	/* Coroutine mechanics for the sillier bits of the code */
	17	#define crBegin1 static int crLine = 0;
	18	#define crBegin2 switch(crLine) { case 0:;
	19	#define crBegin crBegin1; crBegin2;
	20	#define crFinish(z) } crLine = 0; return (z)
	21	#define crFinishV } crLine = 0; return
	22	#define crReturn(z) \
	23	do {\
	24	crLine=__LINE__; return (z); case __LINE__:;\
	25	} while (0)
	26	#define crReturnV \
	27	do {\
	28	crLine=__LINE__; return; case __LINE__:;\
	29	} while (0)
	30	#define crStop(z) do{ crLine = 0; return (z); }while(0)
	31	#define crStopV do{ crLine = 0; return; }while(0)
	32
	33	#ifndef FALSE
	34	#define FALSE 0
	35	#endif
	36	#ifndef TRUE
	37	#define TRUE 1
	38	#endif
	39
	40	static SOCKET s = INVALID_SOCKET;
	41
	42	static unsigned char session_key[32];
	43	static struct ssh_cipher *cipher = NULL;
	44
	45	static char *savedhost;
	46
	47	static enum {
	48	SSH_STATE_BEFORE_SIZE,
	49	SSH_STATE_INTERMED,
21248260	50	SSH_STATE_SESSION,
21248260	51	SSH_STATE_CLOSED
374330e2	52	} ssh_state = SSH_STATE_BEFORE_SIZE;
	53
	54	static int size_needed = FALSE;
	55
	56	static void s_write (char *buf, int len) {
	57	while (len > 0) {
	58	int i = send (s, buf, len, 0);
	59	if (i > 0)
	60	len -= i, buf += i;
	61	}
	62	}
	63
	64	static int s_read (char *buf, int len) {
	65	int ret = 0;
	66	while (len > 0) {
	67	int i = recv (s, buf, len, 0);
	68	if (i > 0)
	69	len -= i, buf += i, ret += i;
	70	else
	71	return i;
	72	}
	73	return ret;
	74	}
	75
	76	static void c_write (char *buf, int len) {
	77	while (len--) {
	78	int new_head = (inbuf_head + 1) & INBUF_MASK;
	79	int c = (unsigned char) *buf;
	80	if (new_head != inbuf_reap) {
	81	inbuf[inbuf_head] = *buf++;
	82	inbuf_head = new_head;
	83	}
	84	}
	85	}
	86
	87	struct Packet {
	88	long length;
	89	int type;
	90	unsigned long crc;
	91	unsigned char *data;
	92	unsigned char *body;
	93	long maxlen;
	94	};
	95
	96	static struct Packet pktin = { 0, 0, 0, NULL, 0 };
	97	static struct Packet pktout = { 0, 0, 0, NULL, 0 };
	98
	99	static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
	100	static void ssh_size(void);
	101
	102	static void ssh_gotdata(unsigned char *data, int datalen) {
	103	static long len, biglen, to_read;
	104	static unsigned char c, *p;
	105	static int i, pad;
	106	static char padding[8];
	107	static unsigned char word[4];
	108
	109	crBegin;
	110	while (1) {
	111	for (i = len = 0; i < 4; i++) {
	112	while (datalen == 0)
	113	crReturnV;
	114	len = (len << 8) + *data;
	115	data++, datalen--;
116	}
117
37508af4	118	#ifdef FWHACK
	119	if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
	120	len = 0x300; /* big enough to carry to end */
	121	}
	122	#endif
	123
374330e2	124	pad = 8 - (len%8);
	125
	126	biglen = len + pad;
	127
	128	len -= 5; /* type and CRC */
	129
	130	pktin.length = len;
	131	if (pktin.maxlen < biglen) {
	132	pktin.maxlen = biglen;
	133	pktin.data = (pktin.data == NULL ? malloc(biglen) :
	134	realloc(pktin.data, biglen));
	135	if (!pktin.data)
	136	fatalbox("Out of memory");
	137	}
	138
	139	p = pktin.data, to_read = biglen;
	140	while (to_read > 0) {
	141	static int chunk;
	142	chunk = to_read;
	143	while (datalen == 0)
	144	crReturnV;
	145	if (chunk > datalen)
	146	chunk = datalen;
	147	memcpy(p, data, chunk);
	148	data += chunk;
	149	datalen -= chunk;
	150	p += chunk;
	151	to_read -= chunk;
	152	}
	153
	154	if (cipher)
	155	cipher->decrypt(pktin.data, biglen);
	156
	157	pktin.type = pktin.data[pad];
	158	pktin.body = pktin.data+pad+1;
	159
	160	if (pktin.type == 36) { /* SSH_MSG_DEBUG */
	161	/* FIXME: log it */
	162	} else
	163	ssh_protocol(NULL, 0, 1);
	164	}
	165	crFinishV;
	166	}
	167
	168	static void s_wrpkt_start(int type, int len) {
	169	int pad, biglen;
	170
	171	len += 5; /* type and CRC */
	172	pad = 8 - (len%8);
	173	biglen = len + pad;
	174
	175	pktout.length = len-5;
	176	if (pktout.maxlen < biglen) {
	177	pktout.maxlen = biglen;
c1f5f956	178	pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
c1f5f956	179	realloc(pktout.data, biglen+4));
374330e2	180	if (!pktout.data)
	181	fatalbox("Out of memory");
	182	}
	183
	184	pktout.type = type;
	185	pktout.body = pktout.data+4+pad+1;
	186	}
	187
	188	static void s_wrpkt(void) {
	189	int pad, len, biglen, i;
	190	unsigned long crc;
	191
	192	len = pktout.length + 5; /* type and CRC */
	193	pad = 8 - (len%8);
	194	biglen = len + pad;
	195
	196	pktout.body[-1] = pktout.type;
	197	for (i=0; i<pad; i++)
	198	pktout.data[i+4] = random_byte();
	199	crc = crc32(pktout.data+4, biglen-4);
	200
	201	pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
	202	pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
	203	pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
	204	pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);
	205
	206	pktout.data[0] = (len >> 24) & 0xFF;
	207	pktout.data[1] = (len >> 16) & 0xFF;
	208	pktout.data[2] = (len >> 8) & 0xFF;
	209	pktout.data[3] = len & 0xFF;
	210
	211	if (cipher)
	212	cipher->encrypt(pktout.data+4, biglen);
	213
	214	s_write(pktout.data, biglen+4);
	215	}
	216
	217	static int do_ssh_init(void) {
	218	char c;
	219	char version[10];
	220	char vstring[40];
	221	int i;
	222
	223	#ifdef FWHACK
	224	i = 0;
	225	while (s_read(&c, 1) == 1) {
	226	if (c == 'S' && i < 2) i++;
	227	else if (c == 'S' && i == 2) i = 2;
	228	else if (c == 'H' && i == 2) break;
	229	else i = 0;
	230	}
	231	#else
	232	if (s_read(&c,1) != 1 \|\| c != 'S') return 0;
	233	if (s_read(&c,1) != 1 \|\| c != 'S') return 0;
	234	if (s_read(&c,1) != 1 \|\| c != 'H') return 0;
	235	#endif
	236	if (s_read(&c,1) != 1 \|\| c != '-') return 0;
	237	i = 0;
	238	while (1) {
	239	if (s_read(&c,1) != 1)
	240	return 0;
	241	if (i >= 0) {
	242	if (c == '-') {
	243	version[i] = '\0';
244	i = -1;
245	} else if (i < sizeof(version)-1)
246	version[i++] = c;
247	}
248	else if (c == '\n')
249	break;
250	}
251
252	sprintf(vstring, "SSH-%s-7.7.7\n",
253	(strcmp(version, "1.5") <= 0 ? version : "1.5"));
254	s_write(vstring, strlen(vstring));
fef97f43	255	return 1;
374330e2	256	}
	257
	258	static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
	259	int i, j, len;
	260	unsigned char session_id[16];
	261	unsigned char rsabuf, keystr1, *keystr2;
	262	unsigned char cookie[8];
	263	struct RSAKey servkey, hostkey;
	264	struct MD5Context md5c;
	265
	266	extern struct ssh_cipher ssh_3des;
	267
	268	crBegin;
	269
	270	random_init();
	271
	272	while (!ispkt)
	273	crReturnV;
	274
	275	if (pktin.type != 2)
	276	fatalbox("Public key packet not received");
	277
	278	memcpy(cookie, pktin.body, 8);
	279
	280	MD5Init(&md5c);
	281
	282	i = makekey(pktin.body+8, &servkey, &keystr1);
	283
	284	j = makekey(pktin.body+8+i, &hostkey, &keystr2);
	285
	286	MD5Update(&md5c, keystr2, hostkey.bytes);
	287	MD5Update(&md5c, keystr1, servkey.bytes);
	288	MD5Update(&md5c, pktin.body, 8);
	289
	290	MD5Final(session_id, &md5c);
	291
	292	for (i=0; i<32; i++)
	293	session_key[i] = random_byte();
	294
	295	len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
	296
	297	rsabuf = malloc(len);
	298	if (!rsabuf)
	299	fatalbox("Out of memory");
	300
	301	verify_ssh_host_key(savedhost, &hostkey);
	302
	303	for (i=0; i<32; i++) {
	304	rsabuf[i] = session_key[i];
	305	if (i < 16)
	306	rsabuf[i] ^= session_id[i];
	307	}
	308
	309	if (hostkey.bytes > servkey.bytes) {
	310	rsaencrypt(rsabuf, 32, &servkey);
	311	rsaencrypt(rsabuf, servkey.bytes, &hostkey);
	312	} else {
	313	rsaencrypt(rsabuf, 32, &hostkey);
	314	rsaencrypt(rsabuf, hostkey.bytes, &servkey);
	315	}
	316
	317	s_wrpkt_start(3, len+15);
	318	pktout.body[0] = 3; /* SSH_CIPHER_3DES */
	319	memcpy(pktout.body+1, cookie, 8);
320	pktout.body[9] = (len*8) >> 8;
321	pktout.body[10] = (len*8) & 0xFF;
322	memcpy(pktout.body+11, rsabuf, len);
323	pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
324	pktout.body[len+13] = pktout.body[len+14] = 0;
325	s_wrpkt();
326
327	free(rsabuf);
328
329	cipher = &ssh_3des;
330	cipher->sesskey(session_key);
331
332	do { crReturnV; } while (!ispkt);
333
334	if (pktin.type != 14)
335	fatalbox("Encryption not successfully enabled");
336
337	fflush(stdout);
338	{
339	static char username[100];
340	static int pos = 0;
341	static char c;
342	if (!*cfg.username) {
343	c_write("login as: ", 10);
344	while (pos >= 0) {
345	do { crReturnV; } while (ispkt);
346	while (inlen--) switch (c = *in++) {
347	case 10: case 13:
348	username[pos] = 0;
349	pos = -1;
350	break;
351	case 8: case 127:
352	if (pos > 0) {
353	c_write("\b \b", 3);
354	pos--;
355	}
356	break;
357	case 21: case 27:
358	while (pos > 0) {
359	c_write("\b \b", 3);
360	pos--;
361	}
362	break;
363	case 3: case 4:
364	random_save_seed();
365	exit(0);
366	break;
367	default:
368	if (c >= ' ' && c <= '~' && pos < 40) {
369	username[pos++] = c;
370	c_write(&c, 1);
371	}
372	break;
373	}
374	}
375	c_write("\r\n", 2);
376	username[strcspn(username, "\n\r")] = '\0';
377	} else {
378	char stuff[200];
379	strncpy(username, cfg.username, 99);
380	username[99] = '\0';
381	sprintf(stuff, "Sent username \"%s\".\r\n", username);
382	c_write(stuff, strlen(stuff));
383	}
384	s_wrpkt_start(4, 4+strlen(username));
385	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
386	pktout.body[3] = strlen(username);
387	memcpy(pktout.body+4, username, strlen(username));
388	s_wrpkt();
389	}
390
391	do { crReturnV; } while (!ispkt);
392
393	while (pktin.type == 15) {
394	static char password[100];
395	static int pos;
396	static char c;
397	c_write("password: ", 10);
398	pos = 0;
399	while (pos >= 0) {
400	do { crReturnV; } while (ispkt);
401	while (inlen--) switch (c = *in++) {
402	case 10: case 13:
403	password[pos] = 0;
404	pos = -1;
405	break;
406	case 8: case 127:
407	if (pos > 0)
408	pos--;
409	break;
410	case 21: case 27:
411	pos = 0;
412	break;
413	case 3: case 4:
414	random_save_seed();
415	exit(0);
416	break;
417	default:
418	if (c >= ' ' && c <= '~' && pos < 40)
419	password[pos++] = c;
420	break;
421	}
422	}
423	c_write("\r\n", 2);
424	s_wrpkt_start(9, 4+strlen(password));
425	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
426	pktout.body[3] = strlen(password);
427	memcpy(pktout.body+4, password, strlen(password));
428	s_wrpkt();
429	memset(password, 0, strlen(password));
430	do { crReturnV; } while (!ispkt);
431	if (pktin.type == 15) {
432	c_write("Access denied\r\n", 15);
433	} else if (pktin.type != 14) {
434	fatalbox("Strange packet received, type %d", pktin.type);
435	}
436	}
437
fef97f43	438	if (!cfg.nopty) {
	439	i = strlen(cfg.termtype);
	440	s_wrpkt_start(10, i+5*4+1);
	441	pktout.body[0] = (i >> 24) & 0xFF;
	442	pktout.body[1] = (i >> 16) & 0xFF;
	443	pktout.body[2] = (i >> 8) & 0xFF;
	444	pktout.body[3] = i & 0xFF;
	445	memcpy(pktout.body+4, cfg.termtype, i);
	446	i += 4;
	447	pktout.body[i++] = (rows >> 24) & 0xFF;
	448	pktout.body[i++] = (rows >> 16) & 0xFF;
	449	pktout.body[i++] = (rows >> 8) & 0xFF;
	450	pktout.body[i++] = rows & 0xFF;
	451	pktout.body[i++] = (cols >> 24) & 0xFF;
	452	pktout.body[i++] = (cols >> 16) & 0xFF;
	453	pktout.body[i++] = (cols >> 8) & 0xFF;
	454	pktout.body[i++] = cols & 0xFF;
	455	memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
	456	s_wrpkt();
	457	ssh_state = SSH_STATE_INTERMED;
	458	do { crReturnV; } while (!ispkt);
	459	if (pktin.type != 14 && pktin.type != 15) {
	460	fatalbox("Protocol confusion");
	461	} else if (pktin.type == 15) {
	462	c_write("Server refused to allocate pty\r\n", 32);
	463	}
374330e2	464	}
	465
	466	s_wrpkt_start(12, 0);
	467	s_wrpkt();
	468
	469	ssh_state = SSH_STATE_SESSION;
	470	if (size_needed)
	471	ssh_size();
	472
	473	while (1) {
	474	crReturnV;
	475	if (ispkt) {
	476	if (pktin.type == 17 \|\| pktin.type == 18) {
	477	long len = 0;
	478	for (i = 0; i < 4; i++)
	479	len = (len << 8) + pktin.body[i];
	480	c_write(pktin.body+4, len);
	481	} else if (pktin.type == 1) {
21248260	482	/* SSH_MSG_DISCONNECT */
21248260	483	ssh_state = SSH_STATE_CLOSED;
374330e2	484	} else if (pktin.type == 14) {
	485	/* SSH_MSG_SUCCESS: may be from EXEC_SHELL on some servers */
	486	} else if (pktin.type == 15) {
	487	/* SSH_MSG_FAILURE: may be from EXEC_SHELL on some servers
	488	* if no pty is available or in other odd cases. Ignore */
	489	} else if (pktin.type == 20) {
	490	/* EXITSTATUS */
	491	s_wrpkt_start(33, 0);
	492	s_wrpkt();
	493	} else {
	494	fatalbox("Strange packet received: type %d", pktin.type);
	495	}
	496	} else {
	497	s_wrpkt_start(16, 4+inlen);
	498	pktout.body[0] = (inlen >> 24) & 0xFF;
	499	pktout.body[1] = (inlen >> 16) & 0xFF;
	500	pktout.body[2] = (inlen >> 8) & 0xFF;
	501	pktout.body[3] = inlen & 0xFF;
	502	memcpy(pktout.body+4, in, inlen);
	503	s_wrpkt();
	504	}
	505	}
	506
	507	crFinishV;
	508	}
	509
	510	/*
	511	* Called to set up the connection. Will arrange for WM_NETEVENT
	512	* messages to be passed to the specified window, whose window
	513	* procedure should then call telnet_msg().
	514	*
	515	* Returns an error message, or NULL on success.
	516	*
	517	* Also places the canonical host name into `realhost'.
	518	*/
	519	static char ssh_init (HWND hwnd, char host, int port, char **realhost) {
	520	SOCKADDR_IN addr;
	521	struct hostent *h;
	522	unsigned long a;
	523	#ifdef FWHACK
	524	char *FWhost;
	525	int FWport;
	526	#endif
	527
	528	savedhost = malloc(1+strlen(host));
	529	if (!savedhost)
	530	fatalbox("Out of memory");
	531	strcpy(savedhost, host);
	532
	533	#ifdef FWHACK
	534	FWhost = host;
	535	FWport = port;
	536	host = FWSTR;
	537	port = 23;
	538	#endif
	539
	540	/*
	541	* Try to find host.
	542	*/
	543	if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
	544	if ( (h = gethostbyname(host)) == NULL)
	545	switch (WSAGetLastError()) {
	546	case WSAENETDOWN: return "Network is down";
	547	case WSAHOST_NOT_FOUND: case WSANO_DATA:
548	return "Host does not exist";
549	case WSATRY_AGAIN: return "Host not found";
550	default: return "gethostbyname: unknown error";
551	}
552	memcpy (&a, h->h_addr, sizeof(a));
553	*realhost = h->h_name;
554	} else
555	*realhost = host;
556	#ifdef FWHACK
557	*realhost = FWhost;
558	#endif
559	a = ntohl(a);
560
561	if (port < 0)
562	port = 22; /* default ssh port */
563
564	/*
565	* Open socket.
566	*/
567	s = socket(AF_INET, SOCK_STREAM, 0);
568	if (s == INVALID_SOCKET)
569	switch (WSAGetLastError()) {
570	case WSAENETDOWN: return "Network is down";
571	case WSAEAFNOSUPPORT: return "TCP/IP support not present";
572	default: return "socket(): unknown error";
573	}
574
575	/*
576	* Bind to local address.
577	*/
578	addr.sin_family = AF_INET;
579	addr.sin_addr.s_addr = htonl(INADDR_ANY);
580	addr.sin_port = htons(0);
581	if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
582	switch (WSAGetLastError()) {
583	case WSAENETDOWN: return "Network is down";
584	default: return "bind(): unknown error";
585	}
586
587	/*
588	* Connect to remote address.
589	*/
590	addr.sin_addr.s_addr = htonl(a);
591	addr.sin_port = htons((short)port);
592	if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
593	switch (WSAGetLastError()) {
594	case WSAENETDOWN: return "Network is down";
595	case WSAECONNREFUSED: return "Connection refused";
596	case WSAENETUNREACH: return "Network is unreachable";
597	case WSAEHOSTUNREACH: return "No route to host";
598	default: return "connect(): unknown error";
599	}
600
601	#ifdef FWHACK
602	send(s, "connect ", 8, 0);
603	send(s, FWhost, strlen(FWhost), 0);
604	{
605	char buf[20];
606	sprintf(buf, " %d\n", FWport);
607	send (s, buf, strlen(buf), 0);
608	}
609	#endif
610
611	if (!do_ssh_init())
612	return "Protocol initialisation error";
613
614	if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ \| FD_CLOSE) == SOCKET_ERROR)
615	switch (WSAGetLastError()) {
616	case WSAENETDOWN: return "Network is down";
617	default: return "WSAAsyncSelect(): unknown error";
618	}
619
620	return NULL;
621	}
622
623	/*
624	* Process a WM_NETEVENT message. Will return 0 if the connection
625	* has closed, or <0 for a socket error.
626	*/
627	static int ssh_msg (WPARAM wParam, LPARAM lParam) {
628	int ret;
629	char buf[256];
630
631	if (s == INVALID_SOCKET) /* how the hell did we get here?! */
632	return -5000;
633
634	if (WSAGETSELECTERROR(lParam) != 0)
635	return -WSAGETSELECTERROR(lParam);
636
637	switch (WSAGETSELECTEVENT(lParam)) {
638	case FD_READ:
639	ret = recv(s, buf, sizeof(buf), 0);
640	if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
641	return 1;
642	if (ret < 0) /* any _other_ error */
643	return -10000-WSAGetLastError();
644	if (ret == 0) {
645	s = INVALID_SOCKET;
646	return 0; /* can't happen, in theory */
647	}
648	ssh_gotdata (buf, ret);
649	return 1;
650	case FD_CLOSE:
651	s = INVALID_SOCKET;
21248260	652	ssh_state = SSH_STATE_CLOSED;
374330e2	653	return 0;
	654	}
	655	return 1; /* shouldn't happen, but WTF */
	656	}
	657
	658	/*
	659	* Called to send data down the Telnet connection.
	660	*/
	661	static void ssh_send (char *buf, int len) {
	662	if (s == INVALID_SOCKET)
	663	return;
	664
	665	ssh_protocol(buf, len, 0);
	666	}
	667
	668	/*
	669	* Called to set the size of the window from Telnet's POV.
	670	*/
	671	static void ssh_size(void) {
	672	switch (ssh_state) {
	673	case SSH_STATE_BEFORE_SIZE:
21248260	674	case SSH_STATE_CLOSED:
374330e2	675	break; /* do nothing */
	676	case SSH_STATE_INTERMED:
	677	size_needed = TRUE; /* buffer for later */
	678	break;
	679	case SSH_STATE_SESSION:
fef97f43	680	if (!cfg.nopty) {
	681	s_wrpkt_start(11, 16);
	682	pktout.body[0] = (rows >> 24) & 0xFF;
	683	pktout.body[1] = (rows >> 16) & 0xFF;
	684	pktout.body[2] = (rows >> 8) & 0xFF;
	685	pktout.body[3] = rows & 0xFF;
	686	pktout.body[4] = (cols >> 24) & 0xFF;
	687	pktout.body[5] = (cols >> 16) & 0xFF;
	688	pktout.body[6] = (cols >> 8) & 0xFF;
	689	pktout.body[7] = cols & 0xFF;
	690	memset(pktout.body+8, 0, 8);
	691	s_wrpkt();
	692	}
374330e2	693	}
	694	}
	695
	696	/*
	697	* (Send Telnet special codes)
	698	*/
	699	static void ssh_special (Telnet_Special code) {
	700	/* do nothing */
	701	}
	702
	703	Backend ssh_backend = {
	704	ssh_init,
	705	ssh_msg,
	706	ssh_send,
	707	ssh_size,
	708	ssh_special
	709	};