*/
#define BUG_CHOKES_ON_SSH1_IGNORE 1
#define BUG_SSH2_HMAC 2
+#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
+
#define GET_32BIT(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 24) | \
(*data)++, (*datalen)--;
}
-#ifdef FWHACK
- if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
- st->len = 0x300; /* big enough to carry to end */
- }
-#endif
-
st->pad = 8 - (st->len % 8);
st->biglen = st->len + st->pad;
pktin.length = st->len - 5;
memcpy(buf + nowlen, pktin.body + 4, msglen);
buf[nowlen + msglen] = '\0';
logevent(buf);
+ bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
+ crReturn(0);
}
crFinish(0);
pktin.data[st->i] = *(*data)++;
(*datalen)--;
}
-#ifdef FWHACK
- if (!memcmp(pktin.data, "Remo", 4)) { /* "Remo"te server has closed ... */
- /* FIXME */
- }
-#endif
+
if (sccipher)
sccipher->decrypt(pktin.data, st->cipherblk);
memcpy(buf + nowlen, pktin.data + 14, msglen);
buf[nowlen + msglen] = '\0';
logevent(buf);
+ bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
+ reason,
+ (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
+ ssh2_disconnect_reasons[reason] : "unknown",
+ buf+nowlen));
+ crReturn(0);
}
crFinish(0);
char *imp; /* pointer to implementation part */
imp = vstring;
imp += strcspn(imp, "-");
- if (*imp)
- imp++;
+ if (*imp) imp++;
imp += strcspn(imp, "-");
- if (*imp)
- imp++;
+ if (*imp) imp++;
ssh_remote_bugs = 0;
if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
!strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
- !strcmp(imp, "1.2.22")) {
+ !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")) {
/*
* These versions don't support SSH1_MSG_IGNORE, so we have
* to use a different defence against password length
logevent("We believe remote version has SSH1 ignore bug");
}
+ if (!strcmp(imp, "Cisco-1.25")) {
+ /*
+ * These versions need a plain password sent; they can't
+ * handle having a null and a random length of data after
+ * the password.
+ */
+ ssh_remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
+ logevent("We believe remote version needs a plain SSH1 password");
+ }
+
if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
!strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
!strncmp(imp, "2.1 ", 4)) {
crReturn(1); /* get another character */
}
- vstring = smalloc(16);
vstrsize = 16;
+ vstring = smalloc(vstrsize);
strcpy(vstring, "SSH-");
vslen = 4;
i = 0;
vstring[vslen] = 0;
vlog = smalloc(20 + vslen);
+ vstring[strcspn (vstring, "\r\n")] = '\0'; /* remove end-of-line chars */
sprintf(vlog, "Server version: %s", vstring);
- ssh_detect_bugs(vstring);
- vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
+ ssh_detect_bugs(vstring);
sfree(vlog);
/*
while (1) {
while (datalen > 0) {
if (s_rdpkt(&data, &datalen) == 0) {
+ if (ssh_state == SSH_STATE_CLOSED) {
+ return;
+ }
ssh_protocol(NULL, 0, 1);
if (ssh_state == SSH_STATE_CLOSED) {
return;
/*
* Try to find host.
*/
+ {
+ char buf[200];
+ sprintf(buf, "Looking up host \"%.170s\"", host);
+ logevent(buf);
+ }
addr = sk_namelookup(host, realhost);
if ((err = sk_addr_error(addr)))
return err;
/*
* Open socket.
*/
+ {
+ char buf[200], addrbuf[100];
+ sk_getaddr(addr, addrbuf, 100);
+ sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
+ logevent(buf);
+ }
s = sk_new(addr, port, 0, 1, &fn_table_ptr);
if ((err = sk_socket_error(s)))
return err;
struct MD5Context md5c;
static unsigned long supported_ciphers_mask, supported_auths_mask;
static int tried_publickey;
+ static int tis_auth_refused, ccard_auth_refused;
static unsigned char session_id[16];
static int cipher_type;
static char username[100];
crWaitUntil(ispkt);
tried_publickey = 0;
+ tis_auth_refused = ccard_auth_refused = 0;
while (pktin.type == SSH1_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
- * or CryptoCard exchange if we're doing TIS or CryptoCard
- * authentication.
- */
pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
+
if (agent_exists()) {
/*
* Attempt RSA authentication using Pageant.
if (*cfg.keyfile && !tried_publickey)
pwpkt_type = SSH1_CMSG_AUTH_RSA;
- if (pktin.type == SSH1_SMSG_FAILURE &&
- cfg.try_tis_auth &&
- (supported_auths_mask & (1 << SSH1_AUTH_TIS))) {
+ if (cfg.try_tis_auth &&
+ (supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
+ !tis_auth_refused) {
pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
logevent("Requested TIS authentication");
send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
logevent("TIS authentication declined");
if (flags & FLAG_INTERACTIVE)
c_write_str("TIS authentication refused.\r\n");
+ tis_auth_refused = 1;
+ continue;
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
if (challengelen > sizeof(prompt) - 1)
challengelen = sizeof(prompt) - 1; /* prevent overrun */
memcpy(prompt, pktin.body + 4, challengelen);
- prompt[challengelen] = '\0';
+ /* Prompt heuristic comes from OpenSSH */
+ strncpy(prompt + challengelen,
+ memchr(prompt, '\n', challengelen) ?
+ "": "\r\nResponse: ",
+ (sizeof prompt) - challengelen);
+ prompt[(sizeof prompt) - 1] = '\0';
}
}
- if (pktin.type == SSH1_SMSG_FAILURE &&
- cfg.try_tis_auth &&
- (supported_auths_mask & (1 << SSH1_AUTH_CCARD))) {
+ if (cfg.try_tis_auth &&
+ (supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
+ !ccard_auth_refused) {
pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
logevent("Requested CryptoCard authentication");
send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
logevent("CryptoCard authentication declined");
c_write_str("CryptoCard authentication refused.\r\n");
+ ccard_auth_refused = 1;
+ continue;
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
if (challengelen > sizeof(prompt) - 1)
challengelen = sizeof(prompt) - 1; /* prevent overrun */
memcpy(prompt, pktin.body + 4, challengelen);
- strncpy(prompt + challengelen, "\r\nResponse : ",
+ strncpy(prompt + challengelen,
+ memchr(prompt, '\n', challengelen) ?
+ "" : "\r\nResponse: ",
sizeof(prompt) - challengelen);
prompt[sizeof(prompt) - 1] = '\0';
}
sfree(comment);
}
+ /*
+ * Show password prompt, having first obtained it via a TIS
+ * or CryptoCard exchange if we're doing TIS or CryptoCard
+ * authentication.
+ */
if (ssh_get_line) {
if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
/*
crReturn(1);
}
} else {
- c_write_str(prompt);
+ /* Prompt may have come from server. We've munged it a bit, so
+ * we know it to be zero-terminated at least once. */
+ c_write_untrusted(prompt, strlen(prompt));
pos = 0;
ssh_send_ok = 1;
while (pos >= 0) {
tried_publickey = 1;
i = loadrsakey(cfg.keyfile, &pubkey, password);
if (i == 0) {
- c_write_str("Couldn't load public key from ");
+ c_write_str("Couldn't load private key from ");
c_write_str(cfg.keyfile);
c_write_str(".\r\n");
continue; /* go and try password */
* use of the fact that the password is interpreted
* as a C string: so we can append a NUL, then some
* random data.
+ *
+ * One server (a Cisco one) can deal with neither
+ * SSH1_MSG_IGNORE _nor_ a padded password string.
+ * For this server we are left with no defences
+ * against password length sniffing.
*/
- if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
- char string[64];
- char *s;
- int len;
-
- len = strlen(password);
- if (len < sizeof(string)) {
- s = string;
- strcpy(string, password);
- len++; /* cover the zero byte */
- while (len < sizeof(string)) {
- string[len++] = (char) random_byte();
- }
- } else {
- s = password;
- }
- send_packet(pwpkt_type, PKT_INT, len,
- PKT_DATA, s, len, PKT_END);
- } else {
+ if (!(ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
+ /*
+ * The server can deal with SSH1_MSG_IGNORE, so
+ * we can use the primary defence.
+ */
int bottom, top, pwlen, i;
char *randomstr;
PKT_STR, randomstr, PKT_END);
}
}
+ logevent("Sending password with camouflage packets");
ssh_pkt_defersend();
+ }
+ else if (!(ssh_remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
+ /*
+ * The server can't deal with SSH1_MSG_IGNORE
+ * but can deal with padded passwords, so we
+ * can use the secondary defence.
+ */
+ char string[64];
+ char *s;
+ int len;
+
+ len = strlen(password);
+ if (len < sizeof(string)) {
+ s = string;
+ strcpy(string, password);
+ len++; /* cover the zero byte */
+ while (len < sizeof(string)) {
+ string[len++] = (char) random_byte();
+ }
+ } else {
+ s = password;
+ }
+ logevent("Sending length-padded password");
+ send_packet(pwpkt_type, PKT_INT, len,
+ PKT_DATA, s, len, PKT_END);
+ } else {
+ /*
+ * The server has _both_
+ * BUG_CHOKES_ON_SSH1_IGNORE and
+ * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
+ * therefore nothing we can do.
+ */
+ int len;
+ len = strlen(password);
+ logevent("Sending unpadded password");
+ send_packet(pwpkt_type, PKT_INT, len,
+ PKT_DATA, password, len, PKT_END);
}
} else {
send_packet(pwpkt_type, PKT_STR, password, PKT_END);
if (eof_needed)
ssh_special(TS_EOF);
- ldisc_send(NULL, 0); /* cause ldisc to notice changes */
+ ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */
ssh_send_ok = 1;
ssh_channels = newtree234(ssh_channelcmp);
while (1) {
* if no pty is available or in other odd cases. Ignore */
} else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
+ /*
+ * In case `helpful' firewalls or proxies tack
+ * extra human-readable text on the end of the
+ * session which we might mistake for another
+ * encrypted packet, we close the session once
+ * we've sent EXIT_CONFIRMATION.
+ */
+ ssh_state = SSH_STATE_CLOSED;
+ crReturnV;
} else {
bombout(("Strange packet received: type %d", pktin.type));
crReturnV;
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
- bombout(("Server got confused by X11 forwarding request"));
+ bombout(("Unexpected response to X11 forwarding request:"
+ " packet type %d", pktin.type));
crReturnV;
}
logevent("X11 forwarding refused");
if (pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
if (pktin.type != SSH2_MSG_REQUEST_FAILURE) {
- bombout(("Server got confused by port forwarding request"));
+ bombout(("Unexpected response to port "
+ "forwarding request: packet type %d",
+ pktin.type));
crReturnV;
}
logevent("Server refused this port forwarding");
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
- bombout(
- ("Server got confused by agent forwarding request"));
+ bombout(("Unexpected response to agent forwarding request:"
+ " packet type %d", pktin.type));
crReturnV;
}
logevent("Agent forwarding refused");
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
- bombout(("Server got confused by pty request"));
+ bombout(("Unexpected response to pty request:"
+ " packet type %d", pktin.type));
crReturnV;
}
c_write_str("Server refused to allocate pty\r\n");
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
- bombout(("Server got confused by shell/command request"));
+ bombout(("Unexpected response to shell/command request:"
+ " packet type %d", pktin.type));
crReturnV;
}
/*
/*
* Transfer data!
*/
- ldisc_send(NULL, 0); /* cause ldisc to notice changes */
+ ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */
ssh_send_ok = 1;
while (1) {
static int try_send;