#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <winsock.h>
#include "putty.h"
#include "ssh.h"
#include "scp.h"
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
#define logevent(s) { logevent(s); \
if (IS_SCP && (scp_flags & SCP_VERBOSE) != 0) \
fprintf(stderr, "%s\n", s); }
#define SSH_MSG_DISCONNECT 1
#define SSH_SMSG_PUBLIC_KEY 2
#define SSH_CMSG_SESSION_KEY 3
#define SSH_CMSG_USER 4
#define SSH_CMSG_AUTH_PASSWORD 9
#define SSH_CMSG_REQUEST_PTY 10
#define SSH_CMSG_WINDOW_SIZE 11
#define SSH_CMSG_EXEC_SHELL 12
#define SSH_CMSG_EXEC_CMD 13
#define SSH_SMSG_SUCCESS 14
#define SSH_SMSG_FAILURE 15
#define SSH_CMSG_STDIN_DATA 16
#define SSH_SMSG_STDOUT_DATA 17
#define SSH_SMSG_STDERR_DATA 18
#define SSH_CMSG_EOF 19
#define SSH_SMSG_EXIT_STATUS 20
#define SSH_CMSG_EXIT_CONFIRMATION 33
#define SSH_MSG_IGNORE 32
#define SSH_MSG_DEBUG 36
#define SSH_CMSG_AUTH_TIS 39
#define SSH_SMSG_AUTH_TIS_CHALLENGE 40
#define SSH_CMSG_AUTH_TIS_RESPONSE 41
#define SSH_AUTH_TIS 5
#define GET_32BIT(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 24) | \
((unsigned long)(unsigned char)(cp)[1] << 16) | \
((unsigned long)(unsigned char)(cp)[2] << 8) | \
((unsigned long)(unsigned char)(cp)[3]))
#define PUT_32BIT(cp, value) { \
(cp)[0] = (unsigned char)((value) >> 24); \
(cp)[1] = (unsigned char)((value) >> 16); \
(cp)[2] = (unsigned char)((value) >> 8); \
(cp)[3] = (unsigned char)(value); }
enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR };
/* 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)
#define crWaitUntil(c) do { crReturn(0); } while (!(c))
static SOCKET s = INVALID_SOCKET;
static unsigned char session_key[32];
static struct ssh_cipher *cipher = NULL;
int scp_flags = 0;
int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = 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 (IS_SCP) {
noise_ultralight(i);
if (i <= 0)
fatalbox("Lost connection while sending");
}
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 (IS_SCP)
noise_ultralight(i);
if (i > 0)
len -= i, buf += i, ret += i;
else
return i;
}
return ret;
}
static void c_write (char *buf, int len) {
if (IS_SCP) {
if (len > 0 && buf[len-1] == '\n') len--;
if (len > 0 && buf[len-1] == '\r') len--;
if (len > 0) { fwrite(buf, len, 1, stderr); fputc('\n', stderr); }
return;
}
while (len--)
c_write1(*buf++);
}
struct Packet {
long length;
int type;
unsigned char *data;
unsigned char *body;
long maxlen;
};
static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
static void ssh_size(void);
/*
* Collect incoming data in the incoming packet buffer.
* Decihper and verify the packet when it is completely read.
* Drop SSH_MSG_DEBUG and SSH_MSG_IGNORE packets.
* Update the *data and *datalen variables.
* Return the additional nr of bytes needed, or 0 when
* a complete packet is available.
*/
static int s_rdpkt(unsigned char **data, int *datalen)
{
static long len, pad, biglen, to_read;
static unsigned long realcrc, gotcrc;
static unsigned char *p;
static int i;
crBegin;
next_packet:
pktin.type = 0;
pktin.length = 0;
for (i = len = 0; i < 4; i++) {
while ((*datalen) == 0)
crReturn(4-i);
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;
pktin.length = len - 5;
if (pktin.maxlen < biglen) {
pktin.maxlen = biglen;
#ifdef MSCRYPTOAPI
/* Allocate enough buffer space for extra block
* for MS CryptEncrypt() */
pktin.data = (pktin.data == NULL ? malloc(biglen+8) :
realloc(pktin.data, biglen+8));
#else
pktin.data = (pktin.data == NULL ? malloc(biglen) :
realloc(pktin.data, biglen));
#endif
if (!pktin.data)
fatalbox("Out of memory");
}
to_read = biglen;
p = pktin.data;
while (to_read > 0) {
static int chunk;
chunk = to_read;
while ((*datalen) == 0)
crReturn(to_read);
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;
realcrc = crc32(pktin.data, biglen-4);
gotcrc = GET_32BIT(pktin.data+biglen-4);
if (gotcrc != realcrc) {
fatalbox("Incorrect CRC received on packet");
}
if (pktin.type == SSH_SMSG_STDOUT_DATA ||
pktin.type == SSH_SMSG_STDERR_DATA ||
pktin.type == SSH_MSG_DEBUG ||
pktin.type == SSH_SMSG_AUTH_TIS_CHALLENGE) {
long strlen = GET_32BIT(pktin.body);
if (strlen + 4 != pktin.length)
fatalbox("Received data packet with bogus string length");
}
if (pktin.type == SSH_MSG_DEBUG) {
/* log debug message */
char buf[80];
int strlen = GET_32BIT(pktin.body);
strcpy(buf, "Remote: ");
if (strlen > 70) strlen = 70;
memcpy(buf+8, pktin.body+4, strlen);
buf[8+strlen] = '\0';
logevent(buf);
goto next_packet;
} else if (pktin.type == SSH_MSG_IGNORE) {
/* do nothing */
goto next_packet;
}
crFinish(0);
}
static void ssh_gotdata(unsigned char *data, int datalen)
{
while (datalen > 0) {
if ( s_rdpkt(&data, &datalen) == 0 ) {
ssh_protocol(NULL, 0, 1);
if (ssh_state == SSH_STATE_CLOSED) {
return;
}
}
}
}
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;
#ifdef MSCRYPTOAPI
/* Allocate enough buffer space for extra block
* for MS CryptEncrypt() */
pktout.data = (pktout.data == NULL ? malloc(biglen+12) :
realloc(pktout.data, biglen+12));
#else
pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
realloc(pktout.data, biglen+4));
#endif
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);
PUT_32BIT(pktout.data+biglen, crc);
PUT_32BIT(pktout.data, len);
if (cipher)
cipher->encrypt(pktout.data+4, biglen);
s_write(pktout.data, biglen+4);
}
/*
* Construct a packet with the specified contents and
* send it to the server.
*/
static void send_packet(int pkttype, ...)
{
va_list args;
unsigned char *p, *argp, argchar;
unsigned long argint;
int pktlen, argtype, arglen;
pktlen = 0;
va_start(args, pkttype);
while ((argtype = va_arg(args, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
(void) va_arg(args, int);
pktlen += 4;
break;
case PKT_CHAR:
(void) va_arg(args, char);
pktlen++;
break;
case PKT_DATA:
(void) va_arg(args, unsigned char *);
arglen = va_arg(args, int);
pktlen += arglen;
break;
case PKT_STR:
argp = va_arg(args, unsigned char *);
arglen = strlen(argp);
pktlen += 4 + arglen;
break;
default:
assert(0);
}
}
va_end(args);
s_wrpkt_start(pkttype, pktlen);
p = pktout.body;
va_start(args, pkttype);
while ((argtype = va_arg(args, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
argint = va_arg(args, int);
PUT_32BIT(p, argint);
p += 4;
break;
case PKT_CHAR:
argchar = va_arg(args, unsigned char);
*p = argchar;
p++;
break;
case PKT_DATA:
argp = va_arg(args, unsigned char *);
arglen = va_arg(args, int);
memcpy(p, argp, arglen);
p += arglen;
break;
case PKT_STR:
argp = va_arg(args, unsigned char *);
arglen = strlen(argp);
PUT_32BIT(p, arglen);
memcpy(p + 4, argp, arglen);
p += 4 + arglen;
break;
}
}
va_end(args);
s_wrpkt();
}
/*
* Connect to specified host and port.
* Returns an error message, or NULL on success.
* Also places the canonical host name into `realhost'.
*/
static char *connect_to_host(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);
if (port < 0)
port = 22; /* default ssh port */
#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);
/*
* 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
return NULL;
}
static int ssh_versioncmp(char *a, char *b) {
char *ae, *be;
unsigned long av, bv;
av = strtoul(a, &ae, 10);
bv = strtoul(b, &be, 10);
if (av != bv) return (av < bv ? -1 : +1);
if (*ae == '.') ae++;
if (*be == '.') be++;
av = strtoul(ae, &ae, 10);
bv = strtoul(be, &be, 10);
if (av != bv) return (av < bv ? -1 : +1);
return 0;
}
static int do_ssh_init(void) {
char c, *vsp;
char version[10];
char vstring[80];
char vlog[sizeof(vstring)+20];
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
strcpy(vstring, "SSH-");
vsp = vstring+4;
if (s_read(&c,1) != 1 || c != '-') return 0;
i = 0;
while (1) {
if (s_read(&c,1) != 1)
return 0;
if (vsp < vstring+sizeof(vstring)-1)
*vsp++ = c;
if (i >= 0) {
if (c == '-') {
version[i] = '\0';
i = -1;
} else if (i < sizeof(version)-1)
version[i++] = c;
}
else if (c == '\n')
break;
}
*vsp = 0;
sprintf(vlog, "Server version: %s", vstring);
vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
sprintf(vstring, "SSH-%s-PuTTY\n",
(ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
sprintf(vlog, "We claim version: %s", vstring);
vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
s_write(vstring, strlen(vstring));
return 1;
}
/*
* Handle the key exchange and user authentication phases.
*/
static int do_ssh_login(unsigned char *in, int inlen, int ispkt)
{
int i, j, len;
unsigned char session_id[16];
unsigned char *rsabuf, *keystr1, *keystr2;
unsigned char cookie[8];
struct RSAKey servkey, hostkey;
struct MD5Context md5c;
static unsigned long supported_ciphers_mask, supported_auths_mask;
int cipher_type;
extern struct ssh_cipher ssh_3des;
extern struct ssh_cipher ssh_des;
extern struct ssh_cipher ssh_blowfish;
crBegin;
if (!ispkt) crWaitUntil(ispkt);
if (pktin.type != SSH_SMSG_PUBLIC_KEY)
fatalbox("Public key packet not received");
logevent("Received public keys");
memcpy(cookie, pktin.body, 8);
i = makekey(pktin.body+8, &servkey, &keystr1);
j = makekey(pktin.body+8+i, &hostkey, &keystr2);
/*
* Hash the host key and print the hash in the log box. Just as
* a last resort in case the registry's host key checking is
* compromised, we'll allow the user some ability to verify
* host keys by eye.
*/
MD5Init(&md5c);
MD5Update(&md5c, keystr2, hostkey.bytes);
MD5Final(session_id, &md5c);
{
char logmsg[80];
int i;
logevent("Host key MD5 is:");
strcpy(logmsg, " ");
for (i = 0; i < 16; i++)
sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
logevent(logmsg);
}
supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
MD5Init(&md5c);
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 the host key.
*/
{
/*
* First format the key into a string.
*/
int len = rsastr_len(&hostkey);
char *keystr = malloc(len);
if (!keystr)
fatalbox("Out of memory");
rsastr_fmt(keystr, &hostkey);
verify_ssh_host_key(savedhost, keystr);
free(keystr);
}
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);
}
logevent("Encrypted session key");
cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
SSH_CIPHER_3DES;
if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
cipher_type = SSH_CIPHER_3DES;
}
switch (cipher_type) {
case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
}
send_packet(SSH_CMSG_SESSION_KEY,
PKT_CHAR, cipher_type,
PKT_DATA, cookie, 8,
PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
PKT_DATA, rsabuf, len,
PKT_INT, 0,
PKT_END);
logevent("Trying to enable encryption...");
free(rsabuf);
cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
cipher_type == SSH_CIPHER_DES ? &ssh_des :
&ssh_3des;
cipher->sesskey(session_key);
crWaitUntil(ispkt);
if (pktin.type != SSH_SMSG_SUCCESS)
fatalbox("Encryption not successfully enabled");
logevent("Successfully started encryption");
fflush(stdout);
{
static char username[100];
static int pos = 0;
static char c;
if (!IS_SCP && !*cfg.username) {
c_write("login as: ", 10);
while (pos >= 0) {
crWaitUntil(!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 <= '~') ||
((unsigned char)c >= 160)) && 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';
if (!IS_SCP) {
sprintf(stuff, "Sent username \"%s\".\r\n", username);
c_write(stuff, strlen(stuff));
}
}
send_packet(SSH_CMSG_USER, PKT_STR, username, PKT_END);
{
char userlog[20+sizeof(username)];
sprintf(userlog, "Sent username \"%s\"", username);
logevent(userlog);
}
}
crWaitUntil(ispkt);
while (pktin.type == SSH_SMSG_FAILURE) {
static char password[100];
static int pos;
static char c;
static int pwpkt_type;
/*
* Show password prompt, having first obtained it via a TIS
* exchange if we're doing TIS authentication.
*/
pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
if (IS_SCP) {
char prompt[200];
sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost);
if (!ssh_get_password(prompt, password, sizeof(password))) {
/*
* get_password failed to get a password (for
* example because one was supplied on the command
* line which has already failed to work).
* Terminate.
*/
logevent("No more passwords to try");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
}
} else {
if (pktin.type == SSH_SMSG_FAILURE &&
cfg.try_tis_auth &&
(supported_auths_mask & (1<<SSH_AUTH_TIS))) {
pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
logevent("Requested TIS authentication");
send_packet(SSH_CMSG_AUTH_TIS, PKT_END);
crWaitUntil(ispkt);
if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
logevent("TIS authentication declined");
c_write("TIS authentication refused.\r\n", 29);
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
(pktin.body[2] << 8) |
(pktin.body[3]));
logevent("Received TIS challenge");
c_write(pktin.body+4, challengelen);
}
}
if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
c_write("password: ", 10);
pos = 0;
while (pos >= 0) {
crWaitUntil(!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 <= '~') ||
((unsigned char)c >= 160)) && pos < 40)
password[pos++] = c;
break;
}
}
c_write("\r\n", 2);
}
send_packet(pwpkt_type, PKT_STR, password, PKT_END);
logevent("Sent password");
memset(password, 0, strlen(password));
crWaitUntil(ispkt);
if (pktin.type == SSH_SMSG_FAILURE) {
c_write("Access denied\r\n", 15);
logevent("Authentication refused");
} else if (pktin.type == SSH_MSG_DISCONNECT) {
logevent("Received disconnect request");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
} else if (pktin.type != SSH_SMSG_SUCCESS) {
fatalbox("Strange packet received, type %d", pktin.type);
}
}
logevent("Authentication successful");
crFinish(1);
}
static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
crBegin;
random_init();
while (!do_ssh_login(in, inlen, ispkt)) {
crReturnV;
}
if (ssh_state == SSH_STATE_CLOSED)
crReturnV;
if (!cfg.nopty) {
send_packet(SSH_CMSG_REQUEST_PTY,
PKT_STR, cfg.termtype,
PKT_INT, rows, PKT_INT, cols,
PKT_INT, 0, PKT_INT, 0,
PKT_CHAR, 0,
PKT_END);
ssh_state = SSH_STATE_INTERMED;
do { crReturnV; } while (!ispkt);
if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
fatalbox("Protocol confusion");
} else if (pktin.type == SSH_SMSG_FAILURE) {
c_write("Server refused to allocate pty\r\n", 32);
}
logevent("Allocated pty");
}
send_packet(SSH_CMSG_EXEC_SHELL, PKT_END);
logevent("Started session");
ssh_state = SSH_STATE_SESSION;
if (size_needed)
ssh_size();
while (1) {
crReturnV;
if (ispkt) {
if (pktin.type == SSH_SMSG_STDOUT_DATA ||
pktin.type == SSH_SMSG_STDERR_DATA) {
long len = GET_32BIT(pktin.body);
c_write(pktin.body+4, len);
} else if (pktin.type == SSH_MSG_DISCONNECT) {
ssh_state = SSH_STATE_CLOSED;
logevent("Received disconnect request");
} else if (pktin.type == SSH_SMSG_SUCCESS) {
/* may be from EXEC_SHELL on some servers */
} else if (pktin.type == SSH_SMSG_FAILURE) {
/* may be from EXEC_SHELL on some servers
* if no pty is available or in other odd cases. Ignore */
} else if (pktin.type == SSH_SMSG_EXIT_STATUS) {
send_packet(SSH_CMSG_EXIT_CONFIRMATION, PKT_END);
} else {
fatalbox("Strange packet received: type %d", pktin.type);
}
} else {
send_packet(SSH_CMSG_STDIN_DATA,
PKT_INT, inlen, PKT_DATA, in, inlen, PKT_END);
}
}
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.
*/
static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
char *p;
#ifdef MSCRYPTOAPI
if(crypto_startup() == 0)
return "Microsoft high encryption pack not installed!";
#endif
p = connect_to_host(host, port, realhost);
if (p != NULL)
return p;
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];
/*
* Because reading less than the whole of the available pending
* data can generate an FD_READ event, we need to allow for the
* possibility that FD_READ may arrive with FD_CLOSE already in
* the queue; so it's possible that we can get here even with s
* invalid. If so, we return 1 and don't worry about it.
*/
if (s == INVALID_SOCKET)
return 1;
if (WSAGETSELECTERROR(lParam) != 0)
return -WSAGETSELECTERROR(lParam);
switch (WSAGETSELECTEVENT(lParam)) {
case FD_READ:
case FD_CLOSE:
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;
}
ssh_gotdata (buf, ret);
if (ssh_state == SSH_STATE_CLOSED) {
closesocket(s);
s = INVALID_SOCKET;
return 0;
}
return 1;
}
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) {
send_packet(SSH_CMSG_WINDOW_SIZE,
PKT_INT, rows, PKT_INT, cols,
PKT_INT, 0, PKT_INT, 0, PKT_END);
}
}
}
/*
* (Send Telnet special codes)
*/
static void ssh_special (Telnet_Special code) {
/* do nothing */
}
/*
* Read and decrypt one incoming SSH packet.
* (only used by pSCP)
*/
static void get_packet(void)
{
unsigned char buf[4096], *p;
long to_read;
int len;
assert(IS_SCP);
p = NULL;
len = 0;
while ((to_read = s_rdpkt(&p, &len)) > 0) {
if (to_read > sizeof(buf)) to_read = sizeof(buf);
len = s_read(buf, to_read);
if (len != to_read) {
closesocket(s);
s = INVALID_SOCKET;
return;
}
p = buf;
}
assert(len == 0);
}
/*
* Receive a block of data over the SSH link. Block until
* all data is available. Return nr of bytes read (0 if lost connection).
* (only used by pSCP)
*/
int ssh_scp_recv(unsigned char *buf, int len)
{
static int pending_input_len = 0;
static unsigned char *pending_input_ptr;
int to_read = len;
assert(IS_SCP);
if (pending_input_len >= to_read) {
memcpy(buf, pending_input_ptr, to_read);
pending_input_ptr += to_read;
pending_input_len -= to_read;
return len;
}
if (pending_input_len > 0) {
memcpy(buf, pending_input_ptr, pending_input_len);
buf += pending_input_len;
to_read -= pending_input_len;
pending_input_len = 0;
}
if (s == INVALID_SOCKET)
return 0;
while (to_read > 0) {
get_packet();
if (s == INVALID_SOCKET)
return 0;
if (pktin.type == SSH_SMSG_STDOUT_DATA) {
int plen = GET_32BIT(pktin.body);
if (plen <= to_read) {
memcpy(buf, pktin.body + 4, plen);
buf += plen;
to_read -= plen;
} else {
memcpy(buf, pktin.body + 4, to_read);
pending_input_len = plen - to_read;
pending_input_ptr = pktin.body + 4 + to_read;
to_read = 0;
}
} else if (pktin.type == SSH_SMSG_STDERR_DATA) {
int plen = GET_32BIT(pktin.body);
fwrite(pktin.body + 4, plen, 1, stderr);
} else if (pktin.type == SSH_MSG_DISCONNECT) {
logevent("Received disconnect request");
} else if (pktin.type == SSH_SMSG_SUCCESS ||
pktin.type == SSH_SMSG_FAILURE) {
/* ignore */
} else if (pktin.type == SSH_SMSG_EXIT_STATUS) {
char logbuf[100];
sprintf(logbuf, "Remote exit status: %d", GET_32BIT(pktin.body));
logevent(logbuf);
send_packet(SSH_CMSG_EXIT_CONFIRMATION, PKT_END);
logevent("Closing connection");
closesocket(s);
s = INVALID_SOCKET;
} else {
fatalbox("Strange packet received: type %d", pktin.type);
}
}
return len;
}
/*
* Send a block of data over the SSH link.
* Block until all data is sent.
* (only used by pSCP)
*/
void ssh_scp_send(unsigned char *buf, int len)
{
assert(IS_SCP);
if (s == INVALID_SOCKET)
return;
send_packet(SSH_CMSG_STDIN_DATA,
PKT_INT, len, PKT_DATA, buf, len, PKT_END);
}
/*
* Send an EOF notification to the server.
* (only used by pSCP)
*/
void ssh_scp_send_eof(void)
{
assert(IS_SCP);
if (s == INVALID_SOCKET)
return;
send_packet(SSH_CMSG_EOF, PKT_END);
}
/*
* Set up the connection, login on the remote host and
* start execution of a command.
* Returns an error message, or NULL on success.
* (only used by pSCP)
*/
char *ssh_scp_init(char *host, int port, char *cmd, char **realhost)
{
char buf[160], *p;
assert(IS_SCP);
#ifdef MSCRYPTOAPI
if (crypto_startup() == 0)
return "Microsoft high encryption pack not installed!";
#endif
p = connect_to_host(host, port, realhost);
if (p != NULL)
return p;
random_init();
if (!do_ssh_init())
return "Protocol initialisation error";
/* Exchange keys and login */
do {
get_packet();
if (s == INVALID_SOCKET)
return "Connection closed by remote host";
} while (!do_ssh_login(NULL, 0, 1));
if (ssh_state == SSH_STATE_CLOSED) {
closesocket(s);
s = INVALID_SOCKET;
return "Session initialisation error";
}
/* Execute command */
sprintf(buf, "Sending command: %.100s", cmd);
logevent(buf);
send_packet(SSH_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
return NULL;
}
Backend ssh_backend = {
ssh_init,
ssh_msg,
ssh_send,
ssh_size,
ssh_special
};