[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;
	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 == 36) {	       /* SSH_MSG_DEBUG */
	    /* FIXME: log it */
	} else if (pktin.type == 32) { /* 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 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;
    unsigned long supported_ciphers_mask;
    int cipher_type;

    extern struct ssh_cipher ssh_3des;
    extern struct ssh_cipher ssh_blowfish;

    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);

    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]);

    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 :
                  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(3, 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 :
             &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;
374330e2	79	if (new_head != inbuf_reap) {
	80	inbuf[inbuf_head] = *buf++;
	81	inbuf_head = new_head;
	82	}
	83	}
	84	}
	85
	86	struct Packet {
	87	long length;
	88	int type;
	89	unsigned long crc;
	90	unsigned char *data;
	91	unsigned char *body;
	92	long maxlen;
	93	};
	94
	95	static struct Packet pktin = { 0, 0, 0, NULL, 0 };
	96	static struct Packet pktout = { 0, 0, 0, NULL, 0 };
	97
	98	static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
	99	static void ssh_size(void);
	100
	101	static void ssh_gotdata(unsigned char *data, int datalen) {
	102	static long len, biglen, to_read;
f67b4e85	103	static unsigned char *p;
374330e2	104	static int i, pad;
374330e2	105
	106	crBegin;
	107	while (1) {
	108	for (i = len = 0; i < 4; i++) {
	109	while (datalen == 0)
	110	crReturnV;
	111	len = (len << 8) + *data;
	112	data++, datalen--;
	113	}
	114
37508af4	115	#ifdef FWHACK
	116	if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
	117	len = 0x300; /* big enough to carry to end */
	118	}
	119	#endif
	120
374330e2	121	pad = 8 - (len%8);
	122
	123	biglen = len + pad;
	124
	125	len -= 5; /* type and CRC */
	126
	127	pktin.length = len;
	128	if (pktin.maxlen < biglen) {
	129	pktin.maxlen = biglen;
	130	pktin.data = (pktin.data == NULL ? malloc(biglen) :
	131	realloc(pktin.data, biglen));
	132	if (!pktin.data)
	133	fatalbox("Out of memory");
	134	}
	135
	136	p = pktin.data, to_read = biglen;
	137	while (to_read > 0) {
	138	static int chunk;
	139	chunk = to_read;
	140	while (datalen == 0)
	141	crReturnV;
	142	if (chunk > datalen)
	143	chunk = datalen;
	144	memcpy(p, data, chunk);
	145	data += chunk;
	146	datalen -= chunk;
	147	p += chunk;
	148	to_read -= chunk;
	149	}
	150
	151	if (cipher)
	152	cipher->decrypt(pktin.data, biglen);
	153
	154	pktin.type = pktin.data[pad];
	155	pktin.body = pktin.data+pad+1;
	156
	157	if (pktin.type == 36) { /* SSH_MSG_DEBUG */
	158	/* FIXME: log it */
96b9dc0a	159	} else if (pktin.type == 32) { /* SSH_MSG_IGNORE */
96b9dc0a	160	/* do nothing */;
374330e2	161	} else
	162	ssh_protocol(NULL, 0, 1);
	163	}
	164	crFinishV;
	165	}
	166
	167	static void s_wrpkt_start(int type, int len) {
	168	int pad, biglen;
	169
	170	len += 5; /* type and CRC */
	171	pad = 8 - (len%8);
	172	biglen = len + pad;
	173
	174	pktout.length = len-5;
	175	if (pktout.maxlen < biglen) {
	176	pktout.maxlen = biglen;
c1f5f956	177	pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
c1f5f956	178	realloc(pktout.data, biglen+4));
374330e2	179	if (!pktout.data)
	180	fatalbox("Out of memory");
	181	}
	182
	183	pktout.type = type;
	184	pktout.body = pktout.data+4+pad+1;
	185	}
	186
	187	static void s_wrpkt(void) {
	188	int pad, len, biglen, i;
	189	unsigned long crc;
	190
	191	len = pktout.length + 5; /* type and CRC */
	192	pad = 8 - (len%8);
	193	biglen = len + pad;
	194
	195	pktout.body[-1] = pktout.type;
	196	for (i=0; i<pad; i++)
	197	pktout.data[i+4] = random_byte();
	198	crc = crc32(pktout.data+4, biglen-4);
	199
	200	pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
	201	pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
	202	pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
	203	pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);
	204
	205	pktout.data[0] = (len >> 24) & 0xFF;
	206	pktout.data[1] = (len >> 16) & 0xFF;
	207	pktout.data[2] = (len >> 8) & 0xFF;
	208	pktout.data[3] = len & 0xFF;
	209
	210	if (cipher)
	211	cipher->encrypt(pktout.data+4, biglen);
	212
	213	s_write(pktout.data, biglen+4);
	214	}
	215
	216	static int do_ssh_init(void) {
	217	char c;
	218	char version[10];
	219	char vstring[40];
	220	int i;
	221
	222	#ifdef FWHACK
	223	i = 0;
	224	while (s_read(&c, 1) == 1) {
	225	if (c == 'S' && i < 2) i++;
	226	else if (c == 'S' && i == 2) i = 2;
	227	else if (c == 'H' && i == 2) break;
	228	else i = 0;
	229	}
	230	#else
	231	if (s_read(&c,1) != 1 \|\| c != 'S') return 0;
	232	if (s_read(&c,1) != 1 \|\| c != 'S') return 0;
	233	if (s_read(&c,1) != 1 \|\| c != 'H') return 0;
	234	#endif
	235	if (s_read(&c,1) != 1 \|\| c != '-') return 0;
	236	i = 0;
	237	while (1) {
	238	if (s_read(&c,1) != 1)
	239	return 0;
	240	if (i >= 0) {
	241	if (c == '-') {
	242	version[i] = '\0';
243	i = -1;
244	} else if (i < sizeof(version)-1)
245	version[i++] = c;
246	}
247	else if (c == '\n')
248	break;
249	}
250
251	sprintf(vstring, "SSH-%s-7.7.7\n",
252	(strcmp(version, "1.5") <= 0 ? version : "1.5"));
253	s_write(vstring, strlen(vstring));
fef97f43	254	return 1;
374330e2	255	}
	256
	257	static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
	258	int i, j, len;
	259	unsigned char session_id[16];
	260	unsigned char rsabuf, keystr1, *keystr2;
	261	unsigned char cookie[8];
	262	struct RSAKey servkey, hostkey;
	263	struct MD5Context md5c;
bea1ef5f	264	unsigned long supported_ciphers_mask;
bea1ef5f	265	int cipher_type;
374330e2	266
374330e2	267	extern struct ssh_cipher ssh_3des;
bea1ef5f	268	extern struct ssh_cipher ssh_blowfish;
374330e2	269
	270	crBegin;
	271
	272	random_init();
	273
	274	while (!ispkt)
	275	crReturnV;
	276
	277	if (pktin.type != 2)
	278	fatalbox("Public key packet not received");
	279
	280	memcpy(cookie, pktin.body, 8);
	281
	282	MD5Init(&md5c);
	283
	284	i = makekey(pktin.body+8, &servkey, &keystr1);
	285
	286	j = makekey(pktin.body+8+i, &hostkey, &keystr2);
	287
bea1ef5f	288	supported_ciphers_mask = (pktin.body[12+i+j] << 24) \|
	289	(pktin.body[13+i+j] << 16) \|
	290	(pktin.body[14+i+j] << 8) \|
	291	(pktin.body[15+i+j]);
	292
374330e2	293	MD5Update(&md5c, keystr2, hostkey.bytes);
	294	MD5Update(&md5c, keystr1, servkey.bytes);
	295	MD5Update(&md5c, pktin.body, 8);
	296
	297	MD5Final(session_id, &md5c);
	298
	299	for (i=0; i<32; i++)
	300	session_key[i] = random_byte();
	301
	302	len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
	303
	304	rsabuf = malloc(len);
	305	if (!rsabuf)
	306	fatalbox("Out of memory");
	307
	308	verify_ssh_host_key(savedhost, &hostkey);
	309
	310	for (i=0; i<32; i++) {
	311	rsabuf[i] = session_key[i];
	312	if (i < 16)
	313	rsabuf[i] ^= session_id[i];
	314	}
	315
	316	if (hostkey.bytes > servkey.bytes) {
	317	rsaencrypt(rsabuf, 32, &servkey);
	318	rsaencrypt(rsabuf, servkey.bytes, &hostkey);
	319	} else {
	320	rsaencrypt(rsabuf, 32, &hostkey);
	321	rsaencrypt(rsabuf, hostkey.bytes, &servkey);
	322	}
	323
bea1ef5f	324	cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
	325	SSH_CIPHER_3DES;
	326	if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
	327	c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
	328	cipher_type = SSH_CIPHER_3DES;
	329	}
	330
374330e2	331	s_wrpkt_start(3, len+15);
bea1ef5f	332	pktout.body[0] = cipher_type;
374330e2	333	memcpy(pktout.body+1, cookie, 8);
	334	pktout.body[9] = (len*8) >> 8;
	335	pktout.body[10] = (len*8) & 0xFF;
	336	memcpy(pktout.body+11, rsabuf, len);
	337	pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
	338	pktout.body[len+13] = pktout.body[len+14] = 0;
	339	s_wrpkt();
	340
	341	free(rsabuf);
	342
bea1ef5f	343	cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
bea1ef5f	344	&ssh_3des;
374330e2	345	cipher->sesskey(session_key);
	346
	347	do { crReturnV; } while (!ispkt);
	348
	349	if (pktin.type != 14)
	350	fatalbox("Encryption not successfully enabled");
	351
	352	fflush(stdout);
	353	{
	354	static char username[100];
	355	static int pos = 0;
	356	static char c;
	357	if (!*cfg.username) {
	358	c_write("login as: ", 10);
	359	while (pos >= 0) {
	360	do { crReturnV; } while (ispkt);
	361	while (inlen--) switch (c = *in++) {
	362	case 10: case 13:
	363	username[pos] = 0;
	364	pos = -1;
	365	break;
	366	case 8: case 127:
	367	if (pos > 0) {
	368	c_write("\b \b", 3);
	369	pos--;
	370	}
	371	break;
	372	case 21: case 27:
	373	while (pos > 0) {
	374	c_write("\b \b", 3);
	375	pos--;
	376	}
	377	break;
	378	case 3: case 4:
	379	random_save_seed();
	380	exit(0);
	381	break;
	382	default:
	383	if (c >= ' ' && c <= '~' && pos < 40) {
	384	username[pos++] = c;
	385	c_write(&c, 1);
	386	}
	387	break;
	388	}
	389	}
	390	c_write("\r\n", 2);
	391	username[strcspn(username, "\n\r")] = '\0';
	392	} else {
	393	char stuff[200];
	394	strncpy(username, cfg.username, 99);
	395	username[99] = '\0';
	396	sprintf(stuff, "Sent username \"%s\".\r\n", username);
	397	c_write(stuff, strlen(stuff));
	398	}
	399	s_wrpkt_start(4, 4+strlen(username));
	400	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
	401	pktout.body[3] = strlen(username);
	402	memcpy(pktout.body+4, username, strlen(username));
	403	s_wrpkt();
	404	}
	405
	406	do { crReturnV; } while (!ispkt);
	407
	408	while (pktin.type == 15) {
409	static char password[100];
410	static int pos;
411	static char c;
412	c_write("password: ", 10);
413	pos = 0;
414	while (pos >= 0) {
415	do { crReturnV; } while (ispkt);
416	while (inlen--) switch (c = *in++) {
417	case 10: case 13:
418	password[pos] = 0;
419	pos = -1;
420	break;
421	case 8: case 127:
422	if (pos > 0)
423	pos--;
424	break;
425	case 21: case 27:
426	pos = 0;
427	break;
428	case 3: case 4:
429	random_save_seed();
430	exit(0);
431	break;
432	default:
433	if (c >= ' ' && c <= '~' && pos < 40)
434	password[pos++] = c;
435	break;
436	}
437	}
438	c_write("\r\n", 2);
439	s_wrpkt_start(9, 4+strlen(password));
440	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
441	pktout.body[3] = strlen(password);
442	memcpy(pktout.body+4, password, strlen(password));
443	s_wrpkt();
444	memset(password, 0, strlen(password));
445	do { crReturnV; } while (!ispkt);
446	if (pktin.type == 15) {
447	c_write("Access denied\r\n", 15);
448	} else if (pktin.type != 14) {
449	fatalbox("Strange packet received, type %d", pktin.type);
450	}
451	}
452
fef97f43	453	if (!cfg.nopty) {
	454	i = strlen(cfg.termtype);
	455	s_wrpkt_start(10, i+5*4+1);
	456	pktout.body[0] = (i >> 24) & 0xFF;
	457	pktout.body[1] = (i >> 16) & 0xFF;
	458	pktout.body[2] = (i >> 8) & 0xFF;
	459	pktout.body[3] = i & 0xFF;
	460	memcpy(pktout.body+4, cfg.termtype, i);
	461	i += 4;
	462	pktout.body[i++] = (rows >> 24) & 0xFF;
	463	pktout.body[i++] = (rows >> 16) & 0xFF;
	464	pktout.body[i++] = (rows >> 8) & 0xFF;
	465	pktout.body[i++] = rows & 0xFF;
	466	pktout.body[i++] = (cols >> 24) & 0xFF;
	467	pktout.body[i++] = (cols >> 16) & 0xFF;
	468	pktout.body[i++] = (cols >> 8) & 0xFF;
	469	pktout.body[i++] = cols & 0xFF;
	470	memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
	471	s_wrpkt();
	472	ssh_state = SSH_STATE_INTERMED;
	473	do { crReturnV; } while (!ispkt);
	474	if (pktin.type != 14 && pktin.type != 15) {
	475	fatalbox("Protocol confusion");
	476	} else if (pktin.type == 15) {
	477	c_write("Server refused to allocate pty\r\n", 32);
	478	}
374330e2	479	}
	480
	481	s_wrpkt_start(12, 0);
	482	s_wrpkt();
	483
	484	ssh_state = SSH_STATE_SESSION;
	485	if (size_needed)
	486	ssh_size();
	487
	488	while (1) {
	489	crReturnV;
	490	if (ispkt) {
	491	if (pktin.type == 17 \|\| pktin.type == 18) {
	492	long len = 0;
	493	for (i = 0; i < 4; i++)
	494	len = (len << 8) + pktin.body[i];
	495	c_write(pktin.body+4, len);
	496	} else if (pktin.type == 1) {
21248260	497	/* SSH_MSG_DISCONNECT */
21248260	498	ssh_state = SSH_STATE_CLOSED;
374330e2	499	} else if (pktin.type == 14) {
	500	/* SSH_MSG_SUCCESS: may be from EXEC_SHELL on some servers */
	501	} else if (pktin.type == 15) {
	502	/* SSH_MSG_FAILURE: may be from EXEC_SHELL on some servers
	503	* if no pty is available or in other odd cases. Ignore */
	504	} else if (pktin.type == 20) {
	505	/* EXITSTATUS */
	506	s_wrpkt_start(33, 0);
	507	s_wrpkt();
	508	} else {
	509	fatalbox("Strange packet received: type %d", pktin.type);
	510	}
	511	} else {
	512	s_wrpkt_start(16, 4+inlen);
	513	pktout.body[0] = (inlen >> 24) & 0xFF;
	514	pktout.body[1] = (inlen >> 16) & 0xFF;
	515	pktout.body[2] = (inlen >> 8) & 0xFF;
	516	pktout.body[3] = inlen & 0xFF;
	517	memcpy(pktout.body+4, in, inlen);
	518	s_wrpkt();
	519	}
	520	}
	521
	522	crFinishV;
	523	}
	524
	525	/*
	526	* Called to set up the connection. Will arrange for WM_NETEVENT
	527	* messages to be passed to the specified window, whose window
	528	* procedure should then call telnet_msg().
	529	*
	530	* Returns an error message, or NULL on success.
	531	*
	532	* Also places the canonical host name into `realhost'.
	533	*/
	534	static char ssh_init (HWND hwnd, char host, int port, char **realhost) {
	535	SOCKADDR_IN addr;
	536	struct hostent *h;
	537	unsigned long a;
	538	#ifdef FWHACK
	539	char *FWhost;
	540	int FWport;
	541	#endif
	542
	543	savedhost = malloc(1+strlen(host));
	544	if (!savedhost)
	545	fatalbox("Out of memory");
	546	strcpy(savedhost, host);
	547
	548	#ifdef FWHACK
	549	FWhost = host;
	550	FWport = port;
	551	host = FWSTR;
	552	port = 23;
	553	#endif
	554
	555	/*
	556	* Try to find host.
	557	*/
	558	if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
	559	if ( (h = gethostbyname(host)) == NULL)
	560	switch (WSAGetLastError()) {
	561	case WSAENETDOWN: return "Network is down";
	562	case WSAHOST_NOT_FOUND: case WSANO_DATA:
563	return "Host does not exist";
564	case WSATRY_AGAIN: return "Host not found";
565	default: return "gethostbyname: unknown error";
566	}
567	memcpy (&a, h->h_addr, sizeof(a));
568	*realhost = h->h_name;
569	} else
570	*realhost = host;
571	#ifdef FWHACK
572	*realhost = FWhost;
573	#endif
574	a = ntohl(a);
575
576	if (port < 0)
577	port = 22; /* default ssh port */
578
579	/*
580	* Open socket.
581	*/
582	s = socket(AF_INET, SOCK_STREAM, 0);
583	if (s == INVALID_SOCKET)
584	switch (WSAGetLastError()) {
585	case WSAENETDOWN: return "Network is down";
586	case WSAEAFNOSUPPORT: return "TCP/IP support not present";
587	default: return "socket(): unknown error";
588	}
589
590	/*
591	* Bind to local address.
592	*/
593	addr.sin_family = AF_INET;
594	addr.sin_addr.s_addr = htonl(INADDR_ANY);
595	addr.sin_port = htons(0);
596	if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
597	switch (WSAGetLastError()) {
598	case WSAENETDOWN: return "Network is down";
599	default: return "bind(): unknown error";
600	}
601
602	/*
603	* Connect to remote address.
604	*/
605	addr.sin_addr.s_addr = htonl(a);
606	addr.sin_port = htons((short)port);
607	if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
608	switch (WSAGetLastError()) {
609	case WSAENETDOWN: return "Network is down";
610	case WSAECONNREFUSED: return "Connection refused";
611	case WSAENETUNREACH: return "Network is unreachable";
612	case WSAEHOSTUNREACH: return "No route to host";
613	default: return "connect(): unknown error";
614	}
615
616	#ifdef FWHACK
617	send(s, "connect ", 8, 0);
618	send(s, FWhost, strlen(FWhost), 0);
619	{
620	char buf[20];
621	sprintf(buf, " %d\n", FWport);
622	send (s, buf, strlen(buf), 0);
623	}
624	#endif
625
626	if (!do_ssh_init())
627	return "Protocol initialisation error";
628
629	if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ \| FD_CLOSE) == SOCKET_ERROR)
630	switch (WSAGetLastError()) {
631	case WSAENETDOWN: return "Network is down";
632	default: return "WSAAsyncSelect(): unknown error";
633	}
634
635	return NULL;
636	}
637
638	/*
639	* Process a WM_NETEVENT message. Will return 0 if the connection
640	* has closed, or <0 for a socket error.
641	*/
642	static int ssh_msg (WPARAM wParam, LPARAM lParam) {
643	int ret;
644	char buf[256];
645
646	if (s == INVALID_SOCKET) /* how the hell did we get here?! */
647	return -5000;
648
649	if (WSAGETSELECTERROR(lParam) != 0)
650	return -WSAGETSELECTERROR(lParam);
651
652	switch (WSAGETSELECTEVENT(lParam)) {
653	case FD_READ:
654	ret = recv(s, buf, sizeof(buf), 0);
655	if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
656	return 1;
657	if (ret < 0) /* any _other_ error */
658	return -10000-WSAGetLastError();
659	if (ret == 0) {
660	s = INVALID_SOCKET;
661	return 0; /* can't happen, in theory */
662	}
663	ssh_gotdata (buf, ret);
664	return 1;
665	case FD_CLOSE:
666	s = INVALID_SOCKET;
21248260	667	ssh_state = SSH_STATE_CLOSED;
374330e2	668	return 0;
	669	}
	670	return 1; /* shouldn't happen, but WTF */
	671	}
	672
	673	/*
	674	* Called to send data down the Telnet connection.
	675	*/
	676	static void ssh_send (char *buf, int len) {
	677	if (s == INVALID_SOCKET)
	678	return;
	679
	680	ssh_protocol(buf, len, 0);
	681	}
	682
	683	/*
	684	* Called to set the size of the window from Telnet's POV.
	685	*/
	686	static void ssh_size(void) {
	687	switch (ssh_state) {
	688	case SSH_STATE_BEFORE_SIZE:
21248260	689	case SSH_STATE_CLOSED:
374330e2	690	break; /* do nothing */
	691	case SSH_STATE_INTERMED:
	692	size_needed = TRUE; /* buffer for later */
	693	break;
	694	case SSH_STATE_SESSION:
fef97f43	695	if (!cfg.nopty) {
	696	s_wrpkt_start(11, 16);
	697	pktout.body[0] = (rows >> 24) & 0xFF;
	698	pktout.body[1] = (rows >> 16) & 0xFF;
	699	pktout.body[2] = (rows >> 8) & 0xFF;
	700	pktout.body[3] = rows & 0xFF;
	701	pktout.body[4] = (cols >> 24) & 0xFF;
	702	pktout.body[5] = (cols >> 16) & 0xFF;
	703	pktout.body[6] = (cols >> 8) & 0xFF;
	704	pktout.body[7] = cols & 0xFF;
	705	memset(pktout.body+8, 0, 8);
	706	s_wrpkt();
	707	}
374330e2	708	}
	709	}
	710
	711	/*
	712	* (Send Telnet special codes)
	713	*/
	714	static void ssh_special (Telnet_Special code) {
	715	/* do nothing */
	716	}
	717
	718	Backend ssh_backend = {
	719	ssh_init,
	720	ssh_msg,
	721	ssh_send,
	722	ssh_size,
	723	ssh_special
	724	};