#define SSH1_BUFFER_LIMIT 32768
#define SSH_MAX_BACKLOG 32768
#define OUR_V2_WINSIZE 16384
+#define OUR_V2_MAXPKT 0x4000UL
const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
struct Packet {
long length;
+ long forcepad; /* Force padding to at least this length */
int type;
unsigned long sequence;
unsigned char *data;
struct logblank_t *blanks;
};
-static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen,
+static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin);
-static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen,
+static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin);
static void ssh1_protocol_setup(Ssh ssh);
static void ssh2_protocol_setup(Ssh ssh);
static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
static int ssh_sendbuffer(void *handle);
-static void ssh_do_close(Ssh ssh);
+static int ssh_do_close(Ssh ssh, int notify_exit);
static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
static int ssh2_pkt_getbool(struct Packet *pkt);
static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
static void ssh2_timer(void *ctx, long now);
-static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen,
+static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
struct Packet *pktin);
struct rdpkt1_state_tag {
tree234 *channels; /* indexed by local id */
struct ssh_channel *mainchan; /* primary session channel */
int exitcode;
+ int close_expected;
tree234 *rportfwds, *portfwds;
int overall_bufsize;
int throttled_all;
int v1_stdout_throttling;
- int v2_outgoing_sequence;
+ unsigned long v2_outgoing_sequence;
int ssh1_rdpkt_crstate;
int ssh2_rdpkt_crstate;
/* ssh1 and ssh2 use this for different things, but both use it */
int protocol_initial_phase_done;
- void (*protocol) (Ssh ssh, unsigned char *in, int inlen,
+ void (*protocol) (Ssh ssh, void *vin, int inlen,
struct Packet *pkt);
struct Packet *(*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
#define bombout(msg) \
do { \
char *text = dupprintf msg; \
- ssh_do_close(ssh); \
+ ssh_do_close(ssh, FALSE); \
logevent(text); \
connection_fatal(ssh->frontend, "%s", text); \
sfree(text); \
{
struct Packet *pkt = ssh_new_packet();
pkt->length = 5;
+ pkt->forcepad = 0;
ssh2_pkt_addbyte(pkt, (unsigned char) pkt_type);
return pkt;
}
/*
* Add padding. At least four bytes, and must also bring total
* length (minus MAC) up to a multiple of the block size.
+ * If pkt->forcepad is set, make sure the packet is at least that size
+ * after padding.
*/
cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
padding = 4;
+ if (pkt->length + padding < pkt->forcepad)
+ padding = pkt->forcepad - pkt->length;
padding +=
(cipherblk - (pkt->length + padding) % cipherblk) % cipherblk;
+ assert(padding <= 255);
maclen = ssh->csmac ? ssh->csmac->len : 0;
ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
pkt->data[4] = padding;
ssh2_pkt_send_noqueue(ssh, pkt);
}
+#if 0 /* disused */
/*
* Either queue or defer a packet, depending on whether queueing is
* set.
else
ssh2_pkt_defer_noqueue(ssh, pkt);
}
+#endif
/*
* Send the whole deferred data block constructed by
if (ssh->cfg.sshbug_rekey2 == FORCE_ON ||
(ssh->cfg.sshbug_rekey2 == AUTO &&
- wc_match("Sun_SSH_1.0", imp))) {
+ (wc_match("OpenSSH_2.[0-4]*", imp) ||
+ wc_match("OpenSSH_2.5.[0-3]*", imp) ||
+ wc_match("Sun_SSH_1.0", imp) ||
+ wc_match("Sun_SSH_1.0.1", imp)))) {
/*
- * These versions have the SSH2 ignore-rekey bug.
+ * These versions have the SSH2 rekey bug.
*/
ssh->remote_bugs |= BUG_SSH2_REKEY;
- logevent("We believe remote version has SSH2 ignore-rekey bug");
+ logevent("We believe remote version has SSH2 rekey bug");
}
}
crFinishV;
}
-static void ssh_do_close(Ssh ssh)
+static int ssh_do_close(Ssh ssh, int notify_exit)
{
- int i;
+ int i, ret = 0;
struct ssh_channel *c;
ssh->state = SSH_STATE_CLOSED;
if (ssh->s) {
sk_close(ssh->s);
ssh->s = NULL;
- notify_remote_exit(ssh->frontend);
+ if (notify_exit)
+ notify_remote_exit(ssh->frontend);
+ else
+ ret = 1;
}
/*
* Now we must shut down any port and X forwardings going
sfree(c);
}
}
+
+ return ret;
+}
+
+static void ssh_log(Plug plug, int type, SockAddr addr, int port,
+ const char *error_msg, int error_code)
+{
+ Ssh ssh = (Ssh) plug;
+ char addrbuf[256], *msg;
+
+ sk_getaddr(addr, addrbuf, lenof(addrbuf));
+
+ if (type == 0)
+ msg = dupprintf("Connecting to %s port %d", addrbuf, port);
+ else
+ msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
+
+ logevent(msg);
}
static int ssh_closing(Plug plug, const char *error_msg, int error_code,
int calling_back)
{
Ssh ssh = (Ssh) plug;
- ssh_do_close(ssh);
+ int need_notify = ssh_do_close(ssh, FALSE);
+
+ if (!error_msg && !ssh->close_expected) {
+ error_msg = "Server unexpectedly closed network connection";
+ }
+
if (error_msg) {
/* A socket error has occurred. */
logevent(error_msg);
connection_fatal(ssh->frontend, "%s", error_msg);
} else {
- /* Otherwise, the remote side closed the connection normally. */
+ logevent("Server closed network connection");
}
+ if (need_notify)
+ notify_remote_exit(ssh->frontend);
return 0;
}
Ssh ssh = (Ssh) plug;
ssh_gotdata(ssh, (unsigned char *)data, len);
if (ssh->state == SSH_STATE_CLOSED) {
- ssh_do_close(ssh);
+ ssh_do_close(ssh, TRUE);
return 0;
}
return 1;
char **realhost, int nodelay, int keepalive)
{
static const struct plug_function_table fn_table = {
+ ssh_log,
ssh_closing,
ssh_receive,
ssh_sent,
/*
* Open socket.
*/
- {
- char addrbuf[100];
- sk_getaddr(addr, addrbuf, 100);
- logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
- }
ssh->fn = &fn_table;
ssh->s = new_connection(addr, *realhost, port,
0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
* Terminate.
*/
logevent("No username provided. Abandoning session.");
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStop(1);
}
PKT_END);
logevent("Unable to authenticate");
connection_fatal(ssh->frontend, "Unable to authenticate");
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStop(1);
}
/* Data sent down one of our channels. */
int i = ssh_pkt_getuint32(pktin);
char *p;
- unsigned int len;
+ int len;
struct ssh_channel *c;
ssh_pkt_getstring(pktin, &p, &len);
* encrypted packet, we close the session once
* we've sent EXIT_CONFIRMATION.
*/
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
}
ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
}
-static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen,
+static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin)
{
+ unsigned char *in=(unsigned char*)vin;
if (ssh->state == SSH_STATE_CLOSED)
return;
/*
* Handle the SSH2 transport layer.
*/
-static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen,
+static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
struct Packet *pktin)
{
+ unsigned char *in = (unsigned char *)vin;
struct do_ssh2_transport_state {
int nbits, pbits, warn;
Bignum p, g, e, f, K;
goto wait_for_rekey; /* this is utterly horrid */
} else {
logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
- logevent((char *)in);
}
}
goto begin_key_exchange;
if (c->closes != 0)
return;
- if (newwin > c->v.v2.locwindow) {
+ /*
+ * Only send a WINDOW_ADJUST if there's significantly more window
+ * available than the other end thinks there is. This saves us
+ * sending a WINDOW_ADJUST for every character in a shell session.
+ *
+ * "Significant" is arbitrarily defined as half the window size.
+ */
+ if (newwin > c->v.v2.locwindow * 2) {
struct Packet *pktout;
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
{
char *data;
- unsigned int length;
+ int length;
unsigned i = ssh_pkt_getuint32(pktin);
struct ssh_channel *c;
c = find234(ssh->channels, &i, ssh_channelfind);
ssh2_pkt_addstring(s->pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, s->pktout);
#endif
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
}
}
ssh2_pkt_addstring(pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, pktout);
connection_fatal(ssh->frontend, "%s", buf);
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
return;
}
if (q >= 0 && q+4 <= len) { \
q = q + 4 + GET_32BIT(p+q); \
if (q >= 0 && q+4 <= len && \
- (q = q + 4 + GET_32BIT(p+q)) && q == len) \
+ ((q = q + 4 + GET_32BIT(p+q))!= 0) && q == len) \
result = TRUE; \
} \
} while(0)
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_adduint32(pktout, c->localid);
ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
- ssh2_pkt_adduint32(pktout, 0x4000UL); /* our max pkt size */
+ ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
ssh2_pkt_send(ssh, pktout);
}
}
* Terminate.
*/
logevent("No username provided. Abandoning session.");
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStopV;
}
logevent("Unable to authenticate");
connection_fatal(ssh->frontend,
"Unable to authenticate");
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStopV;
}
}
} else if (s->method == AUTH_PASSWORD) {
/*
- * We send the password packet lumped tightly together with
- * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
- * string long enough to make the total length of the two
- * packets constant. This should ensure that a passive
- * listener doing traffic analyis can't work out the length
- * of the password.
+ * We pad out the password packet to 256 bytes to make
+ * it harder for an attacker to find the length of the
+ * user's password.
*
- * For this to work, we need an assumption about the
- * maximum length of the password packet. I think 256 is
- * pretty conservative. Anyone using a password longer than
- * that probably doesn't have much to worry about from
+ * Anyone using a password longer than 256 bytes
+ * probably doesn't have much to worry about from
* people who find out how long their password is!
*/
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ s->pktout->forcepad = 256;
ssh2_pkt_addstring(s->pktout, s->username);
ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(s->pktout, "password");
ssh2_pkt_addstring(s->pktout, s->password);
memset(s->password, 0, sizeof(s->password));
end_log_omission(ssh, s->pktout);
- ssh2_pkt_defer(ssh, s->pktout);
- /*
- * We'll include a string that's an exact multiple of the
- * cipher block size. If the cipher is NULL for some
- * reason, we don't do this trick at all because we gain
- * nothing by it.
- */
- if (ssh->cscipher) {
- int stringlen, i;
-
- stringlen = (256 - ssh->deferred_len);
- stringlen += ssh->cscipher->blksize - 1;
- stringlen -= (stringlen % ssh->cscipher->blksize);
- if (ssh->cscomp) {
- /*
- * Temporarily disable actual compression,
- * so we can guarantee to get this string
- * exactly the length we want it. The
- * compression-disabling routine should
- * return an integer indicating how many
- * bytes we should adjust our string length
- * by.
- */
- stringlen -=
- ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
- }
- s->pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
- ssh2_pkt_addstring_start(s->pktout);
- for (i = 0; i < stringlen; i++) {
- char c = (char) random_byte();
- ssh2_pkt_addstring_data(s->pktout, &c, 1);
- }
- ssh2_pkt_defer(ssh, s->pktout);
- }
- ssh_pkt_defersend(ssh);
+ ssh2_pkt_send(ssh, s->pktout);
logevent("Sent password");
s->type = AUTH_TYPE_PASSWORD;
} else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
if (s->curr_prompt == 0) {
s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
+ s->pktout->forcepad = 256;
ssh2_pkt_adduint32(s->pktout, s->num_prompts);
}
if (s->need_pw) { /* only add pw if we just got one! */
" methods available");
ssh2_pkt_addstring(s->pktout, "en"); /* language tag */
ssh2_pkt_send_noqueue(ssh, s->pktout);
+ ssh->close_expected = TRUE;
ssh_closing((Plug)ssh, NULL, 0, 0);
crStopV;
}
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, 0x4000UL); /* our max pkt size */
+ ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT); /* our max pkt size */
ssh2_pkt_send(ssh, s->pktout);
crWaitUntilV(pktin);
if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
}
}
-static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen,
+static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
struct Packet *pktin)
{
+ unsigned char *in = (unsigned char *)vin;
if (ssh->state == SSH_STATE_CLOSED)
return;
ssh->kex_ctx = NULL;
ssh->hostkey = NULL;
ssh->exitcode = -1;
+ ssh->close_expected = FALSE;
ssh->state = SSH_STATE_PREPACKET;
ssh->size_needed = FALSE;
ssh->eof_needed = FALSE;
ssh->crcda_ctx = NULL;
}
if (ssh->s)
- ssh_do_close(ssh);
+ ssh_do_close(ssh, TRUE);
expire_timer_context(ssh);
if (ssh->pinger)
pinger_free(ssh->pinger);
ssh2_pkt_adduint32(pktout, c->localid);
c->v.v2.locwindow = OUR_V2_WINSIZE;
ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
- ssh2_pkt_adduint32(pktout, 0x4000UL); /* our max pkt size */
+ ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
ssh2_pkt_addstring(pktout, hostname);
ssh2_pkt_adduint32(pktout, port);
/*
projects / u / mdw / putty / blobdiff