[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 = 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) :
		       realloc(pktout.data, biglen));
	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));
}

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);
	}
    }

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