[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;
    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;
	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;
bea1ef5f	265	unsigned long supported_ciphers_mask;
bea1ef5f	266	int cipher_type;
374330e2	267
374330e2	268	extern struct ssh_cipher ssh_3des;
bea1ef5f	269	extern struct ssh_cipher ssh_blowfish;
374330e2	270
	271	crBegin;
	272
	273	random_init();
	274
	275	while (!ispkt)
	276	crReturnV;
	277
	278	if (pktin.type != 2)
	279	fatalbox("Public key packet not received");
	280
	281	memcpy(cookie, pktin.body, 8);
	282
	283	MD5Init(&md5c);
	284
	285	i = makekey(pktin.body+8, &servkey, &keystr1);
	286
	287	j = makekey(pktin.body+8+i, &hostkey, &keystr2);
	288
bea1ef5f	289	supported_ciphers_mask = (pktin.body[12+i+j] << 24) \|
	290	(pktin.body[13+i+j] << 16) \|
	291	(pktin.body[14+i+j] << 8) \|
	292	(pktin.body[15+i+j]);
	293
374330e2	294	MD5Update(&md5c, keystr2, hostkey.bytes);
	295	MD5Update(&md5c, keystr1, servkey.bytes);
	296	MD5Update(&md5c, pktin.body, 8);
	297
	298	MD5Final(session_id, &md5c);
	299
	300	for (i=0; i<32; i++)
	301	session_key[i] = random_byte();
	302
	303	len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
	304
	305	rsabuf = malloc(len);
	306	if (!rsabuf)
	307	fatalbox("Out of memory");
	308
	309	verify_ssh_host_key(savedhost, &hostkey);
	310
	311	for (i=0; i<32; i++) {
	312	rsabuf[i] = session_key[i];
	313	if (i < 16)
	314	rsabuf[i] ^= session_id[i];
	315	}
	316
	317	if (hostkey.bytes > servkey.bytes) {
	318	rsaencrypt(rsabuf, 32, &servkey);
	319	rsaencrypt(rsabuf, servkey.bytes, &hostkey);
	320	} else {
	321	rsaencrypt(rsabuf, 32, &hostkey);
	322	rsaencrypt(rsabuf, hostkey.bytes, &servkey);
	323	}
	324
bea1ef5f	325	cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
	326	SSH_CIPHER_3DES;
	327	if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
	328	c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
	329	cipher_type = SSH_CIPHER_3DES;
	330	}
	331
374330e2	332	s_wrpkt_start(3, len+15);
bea1ef5f	333	pktout.body[0] = cipher_type;
374330e2	334	memcpy(pktout.body+1, cookie, 8);
	335	pktout.body[9] = (len*8) >> 8;
	336	pktout.body[10] = (len*8) & 0xFF;
	337	memcpy(pktout.body+11, rsabuf, len);
	338	pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
	339	pktout.body[len+13] = pktout.body[len+14] = 0;
	340	s_wrpkt();
	341
	342	free(rsabuf);
	343
bea1ef5f	344	cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
bea1ef5f	345	&ssh_3des;
374330e2	346	cipher->sesskey(session_key);
	347
	348	do { crReturnV; } while (!ispkt);
	349
	350	if (pktin.type != 14)
	351	fatalbox("Encryption not successfully enabled");
	352
	353	fflush(stdout);
	354	{
	355	static char username[100];
	356	static int pos = 0;
	357	static char c;
	358	if (!*cfg.username) {
	359	c_write("login as: ", 10);
	360	while (pos >= 0) {
	361	do { crReturnV; } while (ispkt);
	362	while (inlen--) switch (c = *in++) {
	363	case 10: case 13:
	364	username[pos] = 0;
	365	pos = -1;
	366	break;
	367	case 8: case 127:
	368	if (pos > 0) {
	369	c_write("\b \b", 3);
	370	pos--;
	371	}
	372	break;
	373	case 21: case 27:
	374	while (pos > 0) {
	375	c_write("\b \b", 3);
	376	pos--;
	377	}
	378	break;
	379	case 3: case 4:
	380	random_save_seed();
	381	exit(0);
	382	break;
	383	default:
	384	if (c >= ' ' && c <= '~' && pos < 40) {
	385	username[pos++] = c;
	386	c_write(&c, 1);
	387	}
	388	break;
	389	}
	390	}
	391	c_write("\r\n", 2);
	392	username[strcspn(username, "\n\r")] = '\0';
	393	} else {
	394	char stuff[200];
	395	strncpy(username, cfg.username, 99);
	396	username[99] = '\0';
	397	sprintf(stuff, "Sent username \"%s\".\r\n", username);
	398	c_write(stuff, strlen(stuff));
	399	}
	400	s_wrpkt_start(4, 4+strlen(username));
	401	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
	402	pktout.body[3] = strlen(username);
	403	memcpy(pktout.body+4, username, strlen(username));
	404	s_wrpkt();
	405	}
	406
	407	do { crReturnV; } while (!ispkt);
	408
	409	while (pktin.type == 15) {
410	static char password[100];
411	static int pos;
412	static char c;
413	c_write("password: ", 10);
414	pos = 0;
415	while (pos >= 0) {
416	do { crReturnV; } while (ispkt);
417	while (inlen--) switch (c = *in++) {
418	case 10: case 13:
419	password[pos] = 0;
420	pos = -1;
421	break;
422	case 8: case 127:
423	if (pos > 0)
424	pos--;
425	break;
426	case 21: case 27:
427	pos = 0;
428	break;
429	case 3: case 4:
430	random_save_seed();
431	exit(0);
432	break;
433	default:
434	if (c >= ' ' && c <= '~' && pos < 40)
435	password[pos++] = c;
436	break;
437	}
438	}
439	c_write("\r\n", 2);
440	s_wrpkt_start(9, 4+strlen(password));
441	pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
442	pktout.body[3] = strlen(password);
443	memcpy(pktout.body+4, password, strlen(password));
444	s_wrpkt();
445	memset(password, 0, strlen(password));
446	do { crReturnV; } while (!ispkt);
447	if (pktin.type == 15) {
448	c_write("Access denied\r\n", 15);
449	} else if (pktin.type != 14) {
450	fatalbox("Strange packet received, type %d", pktin.type);
451	}
452	}
453
fef97f43	454	if (!cfg.nopty) {
	455	i = strlen(cfg.termtype);
	456	s_wrpkt_start(10, i+5*4+1);
	457	pktout.body[0] = (i >> 24) & 0xFF;
	458	pktout.body[1] = (i >> 16) & 0xFF;
	459	pktout.body[2] = (i >> 8) & 0xFF;
	460	pktout.body[3] = i & 0xFF;
	461	memcpy(pktout.body+4, cfg.termtype, i);
	462	i += 4;
	463	pktout.body[i++] = (rows >> 24) & 0xFF;
	464	pktout.body[i++] = (rows >> 16) & 0xFF;
	465	pktout.body[i++] = (rows >> 8) & 0xFF;
	466	pktout.body[i++] = rows & 0xFF;
	467	pktout.body[i++] = (cols >> 24) & 0xFF;
	468	pktout.body[i++] = (cols >> 16) & 0xFF;
	469	pktout.body[i++] = (cols >> 8) & 0xFF;
	470	pktout.body[i++] = cols & 0xFF;
	471	memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
	472	s_wrpkt();
	473	ssh_state = SSH_STATE_INTERMED;
	474	do { crReturnV; } while (!ispkt);
	475	if (pktin.type != 14 && pktin.type != 15) {
	476	fatalbox("Protocol confusion");
	477	} else if (pktin.type == 15) {
	478	c_write("Server refused to allocate pty\r\n", 32);
	479	}
374330e2	480	}
	481
	482	s_wrpkt_start(12, 0);
	483	s_wrpkt();
	484
	485	ssh_state = SSH_STATE_SESSION;
	486	if (size_needed)
	487	ssh_size();
	488
	489	while (1) {
	490	crReturnV;
	491	if (ispkt) {
	492	if (pktin.type == 17 \|\| pktin.type == 18) {
	493	long len = 0;
	494	for (i = 0; i < 4; i++)
	495	len = (len << 8) + pktin.body[i];
	496	c_write(pktin.body+4, len);
	497	} else if (pktin.type == 1) {
21248260	498	/* SSH_MSG_DISCONNECT */
21248260	499	ssh_state = SSH_STATE_CLOSED;
374330e2	500	} else if (pktin.type == 14) {
	501	/* SSH_MSG_SUCCESS: may be from EXEC_SHELL on some servers */
	502	} else if (pktin.type == 15) {
	503	/* SSH_MSG_FAILURE: may be from EXEC_SHELL on some servers
	504	* if no pty is available or in other odd cases. Ignore */
	505	} else if (pktin.type == 20) {
	506	/* EXITSTATUS */
	507	s_wrpkt_start(33, 0);
	508	s_wrpkt();
	509	} else {
	510	fatalbox("Strange packet received: type %d", pktin.type);
	511	}
	512	} else {
	513	s_wrpkt_start(16, 4+inlen);
	514	pktout.body[0] = (inlen >> 24) & 0xFF;
	515	pktout.body[1] = (inlen >> 16) & 0xFF;
	516	pktout.body[2] = (inlen >> 8) & 0xFF;
	517	pktout.body[3] = inlen & 0xFF;
	518	memcpy(pktout.body+4, in, inlen);
	519	s_wrpkt();
	520	}
	521	}
	522
	523	crFinishV;
	524	}
	525
	526	/*
	527	* Called to set up the connection. Will arrange for WM_NETEVENT
	528	* messages to be passed to the specified window, whose window
	529	* procedure should then call telnet_msg().
	530	*
	531	* Returns an error message, or NULL on success.
	532	*
	533	* Also places the canonical host name into `realhost'.
	534	*/
	535	static char ssh_init (HWND hwnd, char host, int port, char **realhost) {
	536	SOCKADDR_IN addr;
	537	struct hostent *h;
	538	unsigned long a;
	539	#ifdef FWHACK
	540	char *FWhost;
	541	int FWport;
	542	#endif
	543
	544	savedhost = malloc(1+strlen(host));
	545	if (!savedhost)
	546	fatalbox("Out of memory");
	547	strcpy(savedhost, host);
	548
	549	#ifdef FWHACK
	550	FWhost = host;
	551	FWport = port;
	552	host = FWSTR;
	553	port = 23;
	554	#endif
	555
	556	/*
	557	* Try to find host.
	558	*/
	559	if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
	560	if ( (h = gethostbyname(host)) == NULL)
	561	switch (WSAGetLastError()) {
	562	case WSAENETDOWN: return "Network is down";
	563	case WSAHOST_NOT_FOUND: case WSANO_DATA:
564	return "Host does not exist";
565	case WSATRY_AGAIN: return "Host not found";
566	default: return "gethostbyname: unknown error";
567	}
568	memcpy (&a, h->h_addr, sizeof(a));
569	*realhost = h->h_name;
570	} else
571	*realhost = host;
572	#ifdef FWHACK
573	*realhost = FWhost;
574	#endif
575	a = ntohl(a);
576
577	if (port < 0)
578	port = 22; /* default ssh port */
579
580	/*
581	* Open socket.
582	*/
583	s = socket(AF_INET, SOCK_STREAM, 0);
584	if (s == INVALID_SOCKET)
585	switch (WSAGetLastError()) {
586	case WSAENETDOWN: return "Network is down";
587	case WSAEAFNOSUPPORT: return "TCP/IP support not present";
588	default: return "socket(): unknown error";
589	}
590
591	/*
592	* Bind to local address.
593	*/
594	addr.sin_family = AF_INET;
595	addr.sin_addr.s_addr = htonl(INADDR_ANY);
596	addr.sin_port = htons(0);
597	if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
598	switch (WSAGetLastError()) {
599	case WSAENETDOWN: return "Network is down";
600	default: return "bind(): unknown error";
601	}
602
603	/*
604	* Connect to remote address.
605	*/
606	addr.sin_addr.s_addr = htonl(a);
607	addr.sin_port = htons((short)port);
608	if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
609	switch (WSAGetLastError()) {
610	case WSAENETDOWN: return "Network is down";
611	case WSAECONNREFUSED: return "Connection refused";
612	case WSAENETUNREACH: return "Network is unreachable";
613	case WSAEHOSTUNREACH: return "No route to host";
614	default: return "connect(): unknown error";
615	}
616
617	#ifdef FWHACK
618	send(s, "connect ", 8, 0);
619	send(s, FWhost, strlen(FWhost), 0);
620	{
621	char buf[20];
622	sprintf(buf, " %d\n", FWport);
623	send (s, buf, strlen(buf), 0);
624	}
625	#endif
626
627	if (!do_ssh_init())
628	return "Protocol initialisation error";
629
630	if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ \| FD_CLOSE) == SOCKET_ERROR)
631	switch (WSAGetLastError()) {
632	case WSAENETDOWN: return "Network is down";
633	default: return "WSAAsyncSelect(): unknown error";
634	}
635
636	return NULL;
637	}
638
639	/*
640	* Process a WM_NETEVENT message. Will return 0 if the connection
641	* has closed, or <0 for a socket error.
642	*/
643	static int ssh_msg (WPARAM wParam, LPARAM lParam) {
644	int ret;
645	char buf[256];
646
647	if (s == INVALID_SOCKET) /* how the hell did we get here?! */
648	return -5000;
649
650	if (WSAGETSELECTERROR(lParam) != 0)
651	return -WSAGETSELECTERROR(lParam);
652
653	switch (WSAGETSELECTEVENT(lParam)) {
654	case FD_READ:
655	ret = recv(s, buf, sizeof(buf), 0);
656	if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
657	return 1;
658	if (ret < 0) /* any _other_ error */
659	return -10000-WSAGetLastError();
660	if (ret == 0) {
661	s = INVALID_SOCKET;
662	return 0; /* can't happen, in theory */
663	}
664	ssh_gotdata (buf, ret);
665	return 1;
666	case FD_CLOSE:
667	s = INVALID_SOCKET;
21248260	668	ssh_state = SSH_STATE_CLOSED;
374330e2	669	return 0;
	670	}
	671	return 1; /* shouldn't happen, but WTF */
	672	}
	673
	674	/*
	675	* Called to send data down the Telnet connection.
	676	*/
	677	static void ssh_send (char *buf, int len) {
	678	if (s == INVALID_SOCKET)
	679	return;
	680
	681	ssh_protocol(buf, len, 0);
	682	}
	683
	684	/*
	685	* Called to set the size of the window from Telnet's POV.
	686	*/
	687	static void ssh_size(void) {
	688	switch (ssh_state) {
	689	case SSH_STATE_BEFORE_SIZE:
21248260	690	case SSH_STATE_CLOSED:
374330e2	691	break; /* do nothing */
	692	case SSH_STATE_INTERMED:
	693	size_needed = TRUE; /* buffer for later */
	694	break;
	695	case SSH_STATE_SESSION:
fef97f43	696	if (!cfg.nopty) {
	697	s_wrpkt_start(11, 16);
	698	pktout.body[0] = (rows >> 24) & 0xFF;
	699	pktout.body[1] = (rows >> 16) & 0xFF;
	700	pktout.body[2] = (rows >> 8) & 0xFF;
	701	pktout.body[3] = rows & 0xFF;
	702	pktout.body[4] = (cols >> 24) & 0xFF;
	703	pktout.body[5] = (cols >> 16) & 0xFF;
	704	pktout.body[6] = (cols >> 8) & 0xFF;
	705	pktout.body[7] = cols & 0xFF;
	706	memset(pktout.body+8, 0, 8);
	707	s_wrpkt();
	708	}
374330e2	709	}
	710	}
	711
	712	/*
	713	* (Send Telnet special codes)
	714	*/
	715	static void ssh_special (Telnet_Special code) {
	716	/* do nothing */
	717	}
	718
	719	Backend ssh_backend = {
	720	ssh_init,
	721	ssh_msg,
	722	ssh_send,
	723	ssh_size,
	724	ssh_special
	725	};