+/*
+ * SSH backend.
+ */
+
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
+#include <limits.h>
#include "putty.h"
#include "tree234.h"
void *cs_comp_ctx, *sc_comp_ctx;
const struct ssh_kex *kex;
const struct ssh_signkey *hostkey;
- unsigned char v2_session_id[32];
+ unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
int v2_session_id_len;
void *kex_ctx;
tree234 *channels; /* indexed by local id */
struct ssh_channel *mainchan; /* primary session channel */
+ int ncmode; /* is primary channel direct-tcpip? */
int exitcode;
int close_expected;
int clean_exit;
/*
* SSH-2 key creation method.
+ * (Currently assumes 2 lots of any hash are sufficient to generate
+ * keys/IVs for any cipher/MAC. SSH2_MKKEY_ITERS documents this assumption.)
*/
+#define SSH2_MKKEY_ITERS (2)
static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, char chr,
unsigned char *keyspace)
{
char *hostkeydata, *sigdata, *keystr, *fingerprint;
int hostkeylen, siglen;
void *hkey; /* actual host key */
- unsigned char exchange_hash[32];
+ unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
int n_preferred_kex;
const struct ssh_kexes *preferred_kex[KEX_MAX];
int n_preferred_ciphers;
s->preferred_kex[s->n_preferred_kex++] =
&ssh_diffiehellman_group1;
break;
- case CIPHER_WARN:
+ case KEX_WARN:
/* Flag for later. Don't bother if it's the last in
* the list. */
if (i < KEX_MAX - 1) {
ssh->kex->groupname);
}
- logevent("Doing Diffie-Hellman key exchange");
+ logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
+ ssh->kex->hash->text_name);
/*
* Now generate and send e for Diffie-Hellman.
*/
* hash from the _first_ key exchange.
*/
{
- unsigned char keyspace[40];
+ unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
+ assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh2_mkkey(ssh,s->K,s->exchange_hash,'C',keyspace);
+ assert((ssh->cscipher->keylen+7) / 8 <=
+ ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,'A',keyspace);
+ assert(ssh->cscipher->blksize <=
+ ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,'E',keyspace);
+ assert(ssh->csmac->len <=
+ ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
+ memset(keyspace, 0, sizeof(keyspace));
}
logeventf(ssh, "Initialised %.200s client->server encryption",
* hash from the _first_ key exchange.
*/
{
- unsigned char keyspace[40];
+ unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
+ assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh2_mkkey(ssh,s->K,s->exchange_hash,'D',keyspace);
+ assert((ssh->sccipher->keylen+7) / 8 <=
+ ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,'B',keyspace);
+ assert(ssh->sccipher->blksize <=
+ ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,'F',keyspace);
+ assert(ssh->scmac->len <=
+ ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
+ memset(keyspace, 0, sizeof(keyspace));
}
logeventf(ssh, "Initialised %.200s server->client encryption",
ssh->sccipher->text_name);
/*
* Create the main session channel.
*/
- if (!ssh->cfg.ssh_no_shell) {
+ if (ssh->cfg.ssh_no_shell) {
+ ssh->mainchan = NULL;
+ } else if (*ssh->cfg.ssh_nc_host) {
+ /*
+ * Just start a direct-tcpip channel and use it as the main
+ * channel.
+ */
+ ssh->mainchan = snew(struct ssh_channel);
+ ssh->mainchan->ssh = ssh;
+ ssh->mainchan->localid = alloc_channel_id(ssh);
+ s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
+ ssh2_pkt_addstring(s->pktout, "direct-tcpip");
+ ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid);
+ ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
+ ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */
+ ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT); /* our max pkt size */
+ ssh2_pkt_addstring(s->pktout, ssh->cfg.ssh_nc_host);
+ ssh2_pkt_adduint32(s->pktout, ssh->cfg.ssh_nc_port);
+ /*
+ * We make up values for the originator data; partly it's
+ * too much hassle to keep track, and partly I'm not
+ * convinced the server should be told details like that
+ * about my local network configuration.
+ * The "originator IP address" is syntactically a numeric
+ * IP address, and some servers (e.g., Tectia) get upset
+ * if it doesn't match this syntax.
+ */
+ ssh2_pkt_addstring(s->pktout, "0.0.0.0");
+ ssh2_pkt_adduint32(s->pktout, 0);
+ ssh2_pkt_send(ssh, s->pktout);
+
+ crWaitUntilV(pktin);
+ if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
+ bombout(("Server refused to open a direct-tcpip channel"));
+ crStopV;
+ /* FIXME: error data comes back in FAILURE packet */
+ }
+ if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
+ bombout(("Server's channel confirmation cited wrong channel"));
+ crStopV;
+ }
+ ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
+ ssh->mainchan->halfopen = FALSE;
+ ssh->mainchan->type = CHAN_MAINSESSION;
+ ssh->mainchan->closes = 0;
+ ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
+ ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
+ bufchain_init(&ssh->mainchan->v.v2.outbuffer);
+ add234(ssh->channels, ssh->mainchan);
+ update_specials_menu(ssh->frontend);
+ logevent("Opened direct-tcpip channel in place of session");
+ ssh->ncmode = TRUE;
+ } else {
ssh->mainchan = snew(struct ssh_channel);
ssh->mainchan->ssh = ssh;
ssh->mainchan->localid = alloc_channel_id(ssh);
add234(ssh->channels, ssh->mainchan);
update_specials_menu(ssh->frontend);
logevent("Opened channel for session");
- } else
- ssh->mainchan = NULL;
+ ssh->ncmode = FALSE;
+ }
/*
* Now we have a channel, make dispatch table entries for
/*
* Potentially enable X11 forwarding.
*/
- if (ssh->mainchan && ssh->cfg.x11_forward) {
+ if (ssh->mainchan && !ssh->ncmode && ssh->cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
/*
* Potentially enable agent forwarding.
*/
- if (ssh->mainchan && ssh->cfg.agentfwd && agent_exists()) {
+ if (ssh->mainchan && !ssh->ncmode && ssh->cfg.agentfwd && agent_exists()) {
logevent("Requesting OpenSSH-style agent forwarding");
s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
/*
* Now allocate a pty for the session.
*/
- if (ssh->mainchan && !ssh->cfg.nopty) {
+ if (ssh->mainchan && !ssh->ncmode && !ssh->cfg.nopty) {
/* Unpick the terminal-speed string. */
/* XXX perhaps we should allow no speeds to be sent. */
ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
* Simplest thing here is to send all the requests at once, and
* then wait for a whole bunch of successes or failures.
*/
- if (ssh->mainchan && *ssh->cfg.environmt) {
+ if (ssh->mainchan && !ssh->ncmode && *ssh->cfg.environmt) {
char *e = ssh->cfg.environmt;
char *var, *varend, *val;
* this twice if the config data has provided a second choice
* of command.
*/
- if (ssh->mainchan) while (1) {
+ if (ssh->mainchan && !ssh->ncmode) while (1) {
int subsys;
char *cmd;
}
}
-static Socket ssh_socket(void *handle)
+static int ssh_connected(void *handle)
{
Ssh ssh = (Ssh) handle;
- return ssh->s;
+ return ssh->s != NULL;
}
static int ssh_sendok(void *handle)
if (ssh->s != NULL)
return -1;
else
- return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
+ return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
}
/*
ssh_size,
ssh_special,
ssh_get_specials,
- ssh_socket,
+ ssh_connected,
ssh_return_exitcode,
ssh_sendok,
ssh_ldisc,
projects / u / mdw / putty / blobdiff