#define SSH1_AUTH_TIS 5 /* 0x5 */
#define SSH1_AUTH_CCARD 16 /* 0x10 */
+#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
+/* Mask for protoflags we will echo back to server if seen */
+#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
+
#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
#define SSH2_MSG_IGNORE 2 /* 0x2 */
#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
+#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
+#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
+#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
+#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
+
+static const char *const ssh2_disconnect_reasons[] = {
+ NULL,
+ "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
+ "SSH_DISCONNECT_PROTOCOL_ERROR",
+ "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
+ "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
+ "SSH_DISCONNECT_MAC_ERROR",
+ "SSH_DISCONNECT_COMPRESSION_ERROR",
+ "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
+ "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
+ "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
+ "SSH_DISCONNECT_CONNECTION_LOST",
+ "SSH_DISCONNECT_BY_APPLICATION",
+ "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
+ "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
+ "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
+ "SSH_DISCONNECT_ILLEGAL_USER_NAME",
+};
#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
+/*
+ * Various remote-bug flags.
+ */
+#define BUG_CHOKES_ON_SSH1_IGNORE 1
+#define BUG_SSH2_HMAC 2
+
#define GET_32BIT(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 24) | \
((unsigned long)(unsigned char)(cp)[1] << 16) | \
};
const static struct ssh_kex *kex_algs[] = {
-#ifdef DO_DIFFIE_HELLMAN_GEX
&ssh_diffiehellman_gex,
-#endif
&ssh_diffiehellman };
const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
unsigned char **outblock, int *outlen) {
return 0;
}
+static int ssh_comp_none_disable(void) { return 0; }
const static struct ssh_compress ssh_comp_none = {
"none",
ssh_comp_none_init, ssh_comp_none_block,
- ssh_comp_none_init, ssh_comp_none_block
+ ssh_comp_none_init, ssh_comp_none_block,
+ ssh_comp_none_disable
};
extern const struct ssh_compress ssh_zlib;
const static struct ssh_compress *compressions[] = {
static unsigned char session_key[32];
static int ssh1_compressing;
+static int ssh1_remote_protoflags;
+static int ssh1_local_protoflags;
static int ssh_agentfwd_enabled;
static int ssh_X11_fwd_enabled;
+static int ssh_remote_bugs;
static const struct ssh_cipher *cipher = NULL;
static const struct ssh2_cipher *cscipher = NULL;
static const struct ssh2_cipher *sccipher = NULL;
static const struct ssh_kex *kex = NULL;
static const struct ssh_signkey *hostkey = NULL;
static unsigned char ssh2_session_id[20];
-int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
+int (*ssh_get_line)(const char *prompt, char *str, int maxlen,
+ int is_pw) = NULL;
static char *savedhost;
static int savedport;
from_backend(1, buf, len);
}
+static void c_write_untrusted(char *buf, int len) {
+ int i;
+ for (i = 0; i < len; i++) {
+ if (buf[i] == '\n')
+ c_write("\r\n", 2);
+ else if ((buf[i] & 0x60) || (buf[i] == '\r'))
+ c_write(buf+i, 1);
+ }
+}
+
static void c_write_str (char *buf) {
c_write(buf, strlen(buf));
}
unsigned char *decompblk;
int decomplen;
#if 0
- int i;
- debug(("Packet payload pre-decompression:\n"));
- for (i = -1; i < pktin.length; i++)
- debug((" %02x", (unsigned char)pktin.body[i]));
- debug(("\r\n"));
+ {
+ int i;
+ debug(("Packet payload pre-decompression:\n"));
+ for (i = -1; i < pktin.length; i++)
+ debug((" %02x", (unsigned char)pktin.body[i]));
+ debug(("\r\n"));
+ }
#endif
zlib_decompress_block(pktin.body-1, pktin.length+1,
&decompblk, &decomplen);
sfree(decompblk);
pktin.length = decomplen-1;
#if 0
- debug(("Packet payload post-decompression:\n"));
- for (i = -1; i < pktin.length; i++)
- debug((" %02x", (unsigned char)pktin.body[i]));
- debug(("\r\n"));
+ {
+ int i;
+ debug(("Packet payload post-decompression:\n"));
+ for (i = -1; i < pktin.length; i++)
+ debug((" %02x", (unsigned char)pktin.body[i]));
+ debug(("\r\n"));
+ }
#endif
}
goto next_packet;
}
+ if (pktin.type == SSH1_MSG_DISCONNECT) {
+ /* log reason code in disconnect message */
+ char buf[256];
+ int msglen = GET_32BIT(pktin.body);
+ int nowlen;
+ strcpy(buf, "Remote sent disconnect: ");
+ nowlen = strlen(buf);
+ if (msglen > sizeof(buf)-nowlen-1)
+ msglen = sizeof(buf)-nowlen-1;
+ memcpy(buf+nowlen, pktin.body+4, msglen);
+ buf[nowlen+msglen] = '\0';
+ logevent(buf);
+ }
+
crFinish(0);
}
if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
goto next_packet; /* FIXME: print DEBUG message */
+ if (pktin.type == SSH2_MSG_DISCONNECT) {
+ /* log reason code in disconnect message */
+ char buf[256];
+ int reason = GET_32BIT(pktin.data+6);
+ int msglen = GET_32BIT(pktin.data+10);
+ int nowlen;
+ if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
+ sprintf(buf, "Received disconnect message (%s)",
+ ssh2_disconnect_reasons[reason]);
+ } else {
+ sprintf(buf, "Received disconnect message (unknown type %d)", reason);
+ }
+ logevent(buf);
+ strcpy(buf, "Disconnection message text: ");
+ nowlen = strlen(buf);
+ if (msglen > sizeof(buf)-nowlen-1)
+ msglen = sizeof(buf)-nowlen-1;
+ memcpy(buf+nowlen, pktin.data+14, msglen);
+ buf[nowlen+msglen] = '\0';
+ logevent(buf);
+ }
+
crFinish(0);
}
pktout.type = type;
}
-static void s_wrpkt(void) {
+static int s_wrpkt_prepare(void) {
int pad, len, biglen, i;
unsigned long crc;
pktout.body[-1] = pktout.type;
+#if 0
+ debug(("Packet payload pre-compression:\n"));
+ for (i = -1; i < pktout.length; i++)
+ debug((" %02x", (unsigned char)pktout.body[i]));
+ debug(("\r\n"));
+#endif
+
if (ssh1_compressing) {
unsigned char *compblk;
int complen;
-#if 0
- debug(("Packet payload pre-compression:\n"));
- for (i = -1; i < pktout.length; i++)
- debug((" %02x", (unsigned char)pktout.body[i]));
- debug(("\r\n"));
-#endif
zlib_compress_block(pktout.body-1, pktout.length+1,
&compblk, &complen);
ssh1_pktout_size(complen-1);
if (cipher)
cipher->encrypt(pktout.data+4, biglen);
- sk_write(s, pktout.data, biglen+4);
+ return biglen+4;
+}
+
+static void s_wrpkt(void) {
+ int len;
+ len = s_wrpkt_prepare();
+ sk_write(s, pktout.data, len);
+}
+
+static void s_wrpkt_defer(void) {
+ int len;
+ len = s_wrpkt_prepare();
+ if (deferred_len + len > deferred_size) {
+ deferred_size = deferred_len + len + 128;
+ deferred_send_data = srealloc(deferred_send_data, deferred_size);
+ }
+ memcpy(deferred_send_data+deferred_len, pktout.data, len);
+ deferred_len += len;
}
/*
- * Construct a packet with the specified contents and
- * send it to the server.
+ * Construct a packet with the specified contents.
*/
-static void send_packet(int pkttype, ...)
+static void construct_packet(int pkttype, va_list ap1, va_list ap2)
{
- va_list args;
unsigned char *p, *argp, argchar;
unsigned long argint;
int pktlen, argtype, arglen;
Bignum bn;
pktlen = 0;
- va_start(args, pkttype);
- while ((argtype = va_arg(args, int)) != PKT_END) {
+ while ((argtype = va_arg(ap1, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
- (void) va_arg(args, int);
+ (void) va_arg(ap1, int);
pktlen += 4;
break;
case PKT_CHAR:
- (void) va_arg(args, char);
+ (void) va_arg(ap1, char);
pktlen++;
break;
case PKT_DATA:
- (void) va_arg(args, unsigned char *);
- arglen = va_arg(args, int);
+ (void) va_arg(ap1, unsigned char *);
+ arglen = va_arg(ap1, int);
pktlen += arglen;
break;
case PKT_STR:
- argp = va_arg(args, unsigned char *);
+ argp = va_arg(ap1, unsigned char *);
arglen = strlen(argp);
pktlen += 4 + arglen;
break;
case PKT_BIGNUM:
- bn = va_arg(args, Bignum);
+ bn = va_arg(ap1, Bignum);
pktlen += ssh1_bignum_length(bn);
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) {
+ while ((argtype = va_arg(ap2, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
- argint = va_arg(args, int);
+ argint = va_arg(ap2, int);
PUT_32BIT(p, argint);
p += 4;
break;
case PKT_CHAR:
- argchar = va_arg(args, unsigned char);
+ argchar = va_arg(ap2, unsigned char);
*p = argchar;
p++;
break;
case PKT_DATA:
- argp = va_arg(args, unsigned char *);
- arglen = va_arg(args, int);
+ argp = va_arg(ap2, unsigned char *);
+ arglen = va_arg(ap2, int);
memcpy(p, argp, arglen);
p += arglen;
break;
case PKT_STR:
- argp = va_arg(args, unsigned char *);
+ argp = va_arg(ap2, unsigned char *);
arglen = strlen(argp);
PUT_32BIT(p, arglen);
memcpy(p + 4, argp, arglen);
p += 4 + arglen;
break;
case PKT_BIGNUM:
- bn = va_arg(args, Bignum);
+ bn = va_arg(ap2, Bignum);
p += ssh1_write_bignum(p, bn);
break;
}
}
- va_end(args);
+}
+static void send_packet(int pkttype, ...) {
+ va_list ap1, ap2;
+ va_start(ap1, pkttype);
+ va_start(ap2, pkttype);
+ construct_packet(pkttype, ap1, ap2);
s_wrpkt();
}
+static void defer_packet(int pkttype, ...) {
+ va_list ap1, ap2;
+ va_start(ap1, pkttype);
+ va_start(ap2, pkttype);
+ construct_packet(pkttype, ap1, ap2);
+ s_wrpkt_defer();
+}
+
static int ssh_versioncmp(char *a, char *b) {
char *ae, *be;
unsigned long av, bv;
}
static char *ssh2_mpint_fmt(Bignum b, int *len) {
unsigned char *p;
- int i, n = (ssh1_bignum_bitcount(b)+7)/8;
+ int i, n = (bignum_bitcount(b)+7)/8;
p = smalloc(n + 1);
if (!p)
fatalbox("out of memory");
/*
* Send the whole deferred data block constructed by
- * ssh2_pkt_defer().
+ * ssh2_pkt_defer() or SSH1's defer_packet().
*/
-static void ssh2_pkt_defersend(void) {
+static void ssh_pkt_defersend(void) {
sk_write(s, deferred_send_data, deferred_len);
deferred_len = deferred_size = 0;
sfree(deferred_send_data);
return b;
}
+/*
+ * Examine the remote side's version string and compare it against
+ * a list of known buggy implementations.
+ */
+static void ssh_detect_bugs(char *vstring) {
+ char *imp; /* pointer to implementation part */
+ imp = vstring;
+ imp += strcspn(imp, "-");
+ if (*imp) imp++;
+ imp += strcspn(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")) {
+ /*
+ * These versions don't support SSH1_MSG_IGNORE, so we have
+ * to use a different defence against password length
+ * sniffing.
+ */
+ ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
+ logevent("We believe remote version has SSH1 ignore bug");
+ }
+
+ 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)) {
+ /*
+ * These versions have the HMAC bug.
+ */
+ ssh_remote_bugs |= BUG_SSH2_HMAC;
+ logevent("We believe remote version has SSH2 HMAC bug");
+ }
+}
+
static int do_ssh_init(unsigned char c) {
- static char *vsp;
+ static char vslen;
static char version[10];
- static char vstring[80];
- static char vlog[sizeof(vstring)+20];
+ static char *vstring;
+ static int vstrsize;
+ static char *vlog;
static int i;
crBegin;
crReturn(1); /* get another character */
}
+ vstring = smalloc(16);
+ vstrsize = 16;
strcpy(vstring, "SSH-");
- vsp = vstring+4;
+ vslen = 4;
i = 0;
while (1) {
crReturn(1); /* get another char */
- if (vsp < vstring+sizeof(vstring)-1)
- *vsp++ = c;
+ if (vslen >= vstrsize-1) {
+ vstrsize += 16;
+ vstring = srealloc(vstring, vstrsize);
+ }
+ vstring[vslen++] = c;
if (i >= 0) {
if (c == '-') {
version[i] = '\0';
ssh_agentfwd_enabled = FALSE;
rdpkt2_state.incoming_sequence = 0;
- *vsp = 0;
+ vstring[vslen] = 0;
+ vlog = smalloc(20 + vslen);
sprintf(vlog, "Server version: %s", vstring);
+ ssh_detect_bugs(vstring);
vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
+ sfree(vlog);
/*
* Server version "1.99" means we can choose whether we use v1
/*
* This is a v2 server. Begin v2 protocol.
*/
- char *verstring = "SSH-2.0-PuTTY";
+ char verstring[80], vlog[100];
+ sprintf(verstring, "SSH-2.0-%s", sshver);
SHA_Init(&exhashbase);
/*
* Hash our version string and their version string.
*/
sha_string(&exhashbase, verstring, strlen(verstring));
sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
- sprintf(vstring, "%s\n", verstring);
sprintf(vlog, "We claim version: %s", verstring);
logevent(vlog);
+ strcat(verstring, "\n");
logevent("Using SSH protocol version 2");
- sk_write(s, vstring, strlen(vstring));
+ sk_write(s, verstring, strlen(verstring));
ssh_protocol = ssh2_protocol;
ssh_version = 2;
s_rdpkt = ssh2_rdpkt;
/*
* This is a v1 server. Begin v1 protocol.
*/
- 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';
+ char verstring[80], vlog[100];
+ sprintf(verstring, "SSH-%s-%s",
+ (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
+ sshver);
+ sprintf(vlog, "We claim version: %s", verstring);
logevent(vlog);
+ strcat(verstring, "\n");
logevent("Using SSH protocol version 1");
- sk_write(s, vstring, strlen(vstring));
+ sk_write(s, verstring, strlen(verstring));
ssh_protocol = ssh1_protocol;
ssh_version = 1;
s_rdpkt = ssh1_rdpkt;
}
ssh_state = SSH_STATE_BEFORE_SIZE;
+ sfree(vstring);
+
crFinish(0);
}
crFinishV;
}
-static int ssh_receive(Socket skt, int urgent, char *data, int len) {
- if (urgent==3) {
+static int ssh_closing (Plug plug, char *error_msg, int error_code, int calling_back) {
+ ssh_state = SSH_STATE_CLOSED;
+ sk_close(s);
+ s = NULL;
+ if (error_msg) {
/* A socket error has occurred. */
- ssh_state = SSH_STATE_CLOSED;
- sk_close(s);
- s = NULL;
- connection_fatal(data);
- return 0;
- } else if (!len) {
- /* Connection has closed. */
- ssh_state = SSH_STATE_CLOSED;
- sk_close(s);
- s = NULL;
- return 0;
+ connection_fatal (error_msg);
+ } else {
+ /* Otherwise, the remote side closed the connection normally. */
}
+ return 0;
+}
+
+static int ssh_receive(Plug plug, int urgent, char *data, int len) {
ssh_gotdata (data, len);
if (ssh_state == SSH_STATE_CLOSED) {
if (s) {
*/
static char *connect_to_host(char *host, int port, char **realhost)
{
+ static struct plug_function_table fn_table = {
+ ssh_closing,
+ ssh_receive
+ }, *fn_table_ptr = &fn_table;
+
SockAddr addr;
char *err;
#ifdef FWHACK
/*
* Open socket.
*/
- s = sk_new(addr, port, 0, 1, ssh_receive);
+ s = sk_new(addr, port, 0, 1, &fn_table_ptr);
if ( (err = sk_socket_error(s)) )
return err;
logevent(logmsg);
}
+ ssh1_remote_protoflags = GET_32BIT(pktin.body+8+i+j);
supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
+ ssh1_local_protoflags = ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
+ ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
+
MD5Init(&md5c);
MD5Update(&md5c, keystr2, hostkey.bytes);
MD5Update(&md5c, keystr1, servkey.bytes);
if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
c_write_str("Selected cipher not supported, falling back to 3DES\r\n");
cipher_type = SSH_CIPHER_3DES;
+ if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
+ bombout(("Server violates SSH 1 protocol by "
+ "not supporting 3DES encryption"));
+ crReturn(0);
+ }
}
switch (cipher_type) {
case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
PKT_DATA, cookie, 8,
PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
PKT_DATA, rsabuf, len,
- PKT_INT, 0,
+ PKT_INT, ssh1_local_protoflags,
PKT_END);
logevent("Trying to enable encryption...");
static int pos = 0;
static char c;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
- c_write_str("login as: ");
- ssh_send_ok = 1;
- 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_str("\b \b");
- pos--;
- }
- break;
- case 21: case 27:
- while (pos > 0) {
- c_write_str("\b \b");
- 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_str("\r\n");
- username[strcspn(username, "\n\r")] = '\0';
- } else {
+ if (ssh_get_line) {
+ if (!ssh_get_line("login as: ",
+ username, sizeof(username), FALSE)) {
+ /*
+ * get_line failed to get a username.
+ * Terminate.
+ */
+ logevent("No username provided. Abandoning session.");
+ ssh_state = SSH_STATE_CLOSED;
+ crReturn(1);
+ }
+ } else {
+ c_write_str("login as: ");
+ ssh_send_ok = 1;
+ 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_str("\b \b");
+ pos--;
+ }
+ break;
+ case 21: case 27:
+ while (pos > 0) {
+ c_write_str("\b \b");
+ 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_str("\r\n");
+ username[strcspn(username, "\n\r")] = '\0';
+ }
+ } else {
strncpy(username, cfg.username, 99);
username[99] = '\0';
}
request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
agent_query(request, 5, &r, &responselen);
response = (unsigned char *)r;
- if (response) {
+ if (response && responselen >= 5 &&
+ response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
p = response + 5;
nkeys = GET_32BIT(p); p += 4;
- { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
+ { char buf[64]; sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
logevent(buf); }
for (i = 0; i < nkeys; i++) {
static struct RSAKey key;
PUT_32BIT(agentreq, len);
q = agentreq + 4;
*q++ = SSH1_AGENTC_RSA_CHALLENGE;
- PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
+ PUT_32BIT(q, bignum_bitcount(key.modulus));
q += 4;
q += ssh1_write_bignum(q, key.exponent);
q += ssh1_write_bignum(q, key.modulus);
sfree(comment);
}
- if (ssh_get_password) {
- if (!ssh_get_password(prompt, password, sizeof(password))) {
+ if (ssh_get_line) {
+ if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
/*
- * get_password failed to get a password (for
- * example because one was supplied on the command
- * line which has already failed to work).
- * Terminate.
+ * get_line 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;
break; /* we're through! */
} else {
- send_packet(pwpkt_type, PKT_STR, password, PKT_END);
+ if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
+ /*
+ * Defence against traffic analysis: we send a
+ * whole bunch of packets containing strings of
+ * different lengths. One of these strings is the
+ * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
+ * The others are all random data in
+ * SSH1_MSG_IGNORE packets. This way a passive
+ * listener can't tell which is the password, and
+ * hence can't deduce the password length.
+ *
+ * Anybody with a password length greater than 16
+ * bytes is going to have enough entropy in their
+ * password that a listener won't find it _that_
+ * much help to know how long it is. So what we'll
+ * do is:
+ *
+ * - if password length < 16, we send 15 packets
+ * containing string lengths 1 through 15
+ *
+ * - otherwise, we let N be the nearest multiple
+ * of 8 below the password length, and send 8
+ * packets containing string lengths N through
+ * N+7. This won't obscure the order of
+ * magnitude of the password length, but it will
+ * introduce a bit of extra uncertainty.
+ *
+ * A few servers (the old 1.2.18 through 1.2.22)
+ * can't deal with SSH1_MSG_IGNORE. For these
+ * servers, we need an alternative defence. We make
+ * use of the fact that the password is interpreted
+ * as a C string: so we can append a NUL, then some
+ * random data.
+ */
+ 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 {
+ int bottom, top, pwlen, i;
+ char *randomstr;
+
+ pwlen = strlen(password);
+ if (pwlen < 16) {
+ bottom = 0; /* zero length passwords are OK! :-) */
+ top = 15;
+ } else {
+ bottom = pwlen &~ 7;
+ top = bottom + 7;
+ }
+
+ assert(pwlen >= bottom && pwlen <= top);
+
+ randomstr = smalloc(top+1);
+
+ for (i = bottom; i <= top; i++) {
+ if (i == pwlen)
+ defer_packet(pwpkt_type, PKT_STR, password, PKT_END);
+ else {
+ for (j = 0; j < i; j++) {
+ do {
+ randomstr[j] = random_byte();
+ } while (randomstr[j] == '\0');
+ }
+ randomstr[i] = '\0';
+ defer_packet(SSH1_MSG_IGNORE,
+ PKT_STR, randomstr, PKT_END);
+ }
+ }
+ ssh_pkt_defersend();
+ }
+ } else {
+ send_packet(pwpkt_type, PKT_STR, password, PKT_END);
+ }
}
logevent("Sent password");
memset(password, 0, strlen(password));
}
void sshfwd_close(struct ssh_channel *c) {
- if (c) {
+ if (c && !c->closes) {
if (ssh_version == 1) {
send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END);
} else {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
- send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
- PKT_STR, proto, PKT_STR, data,
- PKT_INT, 0,
- PKT_END);
+ if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
+ send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
+ PKT_STR, proto, PKT_STR, data,
+ PKT_INT, 0,
+ PKT_END);
+ } else {
+ send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
+ PKT_STR, proto, PKT_STR, data,
+ PKT_END);
+ }
do { crReturnV; } while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
zlib_decompress_init();
}
- if (*cfg.remote_cmd)
- send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
+ if (*cfg.remote_cmd_ptr)
+ send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr, PKT_END);
else
send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
logevent("Started session");
if (c) {
int closetype;
closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
- send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
+ if (!(c->closes & closetype))
+ send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
if ((c->closes == 0) && (c->type == CHAN_X11)) {
logevent("X11 connection closed");
assert(c->u.x11.s != NULL);
*/
static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
{
- static int i, j, len, nbits;
+ static int i, j, len, nbits, pbits;
static char *str;
static Bignum p, g, e, f, K;
static int kex_init_value, kex_reply_value;
/*
* Be prepared to work around the buggy MAC problem.
*/
- if (cfg.buggymac)
+ if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
maclist = buggymacs, nmacs = lenof(buggymacs);
else
maclist = macs, nmacs = lenof(macs);
}
/*
+ * Work out the number of bits of key we will need from the key
+ * exchange. We start with the maximum key length of either
+ * cipher...
+ */
+ {
+ int csbits, scbits;
+
+ csbits = cscipher_tobe->keylen;
+ scbits = sccipher_tobe->keylen;
+ nbits = (csbits > scbits ? csbits : scbits);
+ }
+ /* The keys only have 160-bit entropy, since they're based on
+ * a SHA-1 hash. So cap the key size at 160 bits. */
+ if (nbits > 160) nbits = 160;
+
+ /*
* If we're doing Diffie-Hellman group exchange, start by
* requesting a group.
*/
if (kex == &ssh_diffiehellman_gex) {
- int csbits, scbits;
-
logevent("Doing Diffie-Hellman group exchange");
/*
- * Work out number of bits. We start with the maximum key
- * length of either cipher...
- */
- csbits = cscipher_tobe->keylen;
- scbits = sccipher_tobe->keylen;
- nbits = (csbits > scbits ? csbits : scbits);
- /* The keys only have 160-bit entropy, since they're based on
- * a SHA-1 hash. So cap the key size at 160 bits. */
- if (nbits > 160) nbits = 160;
- /*
- * ... and then work out how big a DH group we will need to
- * allow that much data.
- */
- nbits = 512 << ((nbits-1) / 64);
+ * Work out how big a DH group we will need to allow that
+ * much data.
+ */
+ pbits = 512 << ((nbits-1) / 64);
ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
- ssh2_pkt_adduint32(nbits);
+ ssh2_pkt_adduint32(pbits);
ssh2_pkt_send();
crWaitUntil(ispkt);
/*
* Now generate and send e for Diffie-Hellman.
*/
- e = dh_create_e();
+ e = dh_create_e(nbits*2);
ssh2_pkt_init(kex_init_value);
ssh2_pkt_addmp(e);
ssh2_pkt_send();
sha_string(&exhash, hostkeydata, hostkeylen);
if (kex == &ssh_diffiehellman_gex) {
- sha_uint32(&exhash, nbits);
+ sha_uint32(&exhash, pbits);
sha_mpint(&exhash, p);
sha_mpint(&exhash, g);
}
*/
pos = 0;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
- c_write_str("login as: ");
- ssh_send_ok = 1;
- while (pos >= 0) {
- crWaitUntilV(!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_str("\b \b");
- pos--;
- }
- break;
- case 21: case 27:
- while (pos > 0) {
- c_write_str("\b \b");
- 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;
- }
- }
+ if (ssh_get_line) {
+ if (!ssh_get_line("login as: ",
+ username, sizeof(username), FALSE)) {
+ /*
+ * get_line failed to get a username.
+ * Terminate.
+ */
+ logevent("No username provided. Abandoning session.");
+ ssh_state = SSH_STATE_CLOSED;
+ crReturnV;
+ }
+ } else {
+ c_write_str("login as: ");
+ ssh_send_ok = 1;
+ while (pos >= 0) {
+ crWaitUntilV(!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_str("\b \b");
+ pos--;
+ }
+ break;
+ case 21: case 27:
+ while (pos > 0) {
+ c_write_str("\b \b");
+ 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_str("\r\n");
username[strcspn(username, "\n\r")] = '\0';
} else {
if (!gotit)
crWaitUntilV(ispkt);
while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
- /* FIXME: should support this */
+ char *banner;
+ int size;
+ /*
+ * Don't show the banner if we're operating in
+ * non-verbose non-interactive mode. (It's probably
+ * a script, which means nobody will read the
+ * banner _anyway_, and moreover the printing of
+ * the banner will screw up processing on the
+ * output of (say) plink.)
+ */
+ if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
+ ssh2_pkt_getstring(&banner, &size);
+ if (banner)
+ c_write_untrusted(banner, size);
+ }
crWaitUntilV(ispkt);
}
if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
bombout(("Strange packet received during authentication: type %d",
pktin.type));
+ crReturnV;
}
gotit = FALSE;
request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
agent_query(request, 5, &r, &responselen);
response = (unsigned char *)r;
- if (response) {
+ if (response && responselen >= 5 &&
+ response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
p = response + 5;
nkeys = GET_32BIT(p); p += 4;
- { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
+ { char buf[64]; sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
logevent(buf); }
for (i = 0; i < nkeys; i++) {
static char *pkblob, *alg, *commentp;
continue;
}
- c_write_str("Authenticating with public key \"");
- c_write(commentp, commentlen);
- c_write_str("\" from agent\r\n");
+ if (flags & FLAG_VERBOSE) {
+ c_write_str("Authenticating with public key \"");
+ c_write(commentp, commentlen);
+ c_write_str("\" from agent\r\n");
+ }
/*
* Server is willing to accept the key.
}
if (need_pw) {
- if (ssh_get_password) {
- if (!ssh_get_password(pwprompt, password, sizeof(password))) {
+ if (ssh_get_line) {
+ if (!ssh_get_line(pwprompt, password,
+ sizeof(password), TRUE)) {
/*
- * get_password failed to get a password (for
- * example because one was supplied on the command
- * line which has already failed to work).
- * Terminate.
+ * get_line 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;
* reason, we don't do this trick at all because we gain
* nothing by it.
*/
- if (cscipher) {
- int i, j;
+ if (cscipher) {
+ int stringlen, i;
+
+ stringlen = (256 - deferred_len);
+ stringlen += cscipher->blksize - 1;
+ stringlen -= (stringlen % cscipher->blksize);
+ if (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 -= cscomp->disable_compression();
+ }
ssh2_pkt_init(SSH2_MSG_IGNORE);
ssh2_pkt_addstring_start();
- for (i = deferred_len; i <= 256; i += cscipher->blksize) {
- for (j = 0; j < cscipher->blksize; j++) {
- char c = (char)random_byte();
- ssh2_pkt_addstring_data(&c, 1);
- }
+ for (i = 0; i < stringlen; i++) {
+ char c = (char)random_byte();
+ ssh2_pkt_addstring_data(&c, 1);
}
ssh2_pkt_defer();
}
- ssh2_pkt_defersend();
+ ssh_pkt_defersend();
logevent("Sent password");
type = AUTH_TYPE_PASSWORD;
} else {
* Potentially enable agent forwarding.
*/
if (cfg.agentfwd && agent_exists()) {
- char proto[20], data[64];
logevent("Requesting OpenSSH-style agent forwarding");
- x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_addstring("auth-agent-req@openssh.com");
if (cfg.ssh_subsys) {
ssh2_pkt_addstring("subsystem");
ssh2_pkt_addbool(1); /* want reply */
- ssh2_pkt_addstring(cfg.remote_cmd);
- } else if (*cfg.remote_cmd) {
+ ssh2_pkt_addstring(cfg.remote_cmd_ptr);
+ } else if (*cfg.remote_cmd_ptr) {
ssh2_pkt_addstring("exec");
ssh2_pkt_addbool(1); /* want reply */
- ssh2_pkt_addstring(cfg.remote_cmd);
+ ssh2_pkt_addstring(cfg.remote_cmd_ptr);
} else {
ssh2_pkt_addstring("shell");
ssh2_pkt_addbool(1); /* want reply */
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
- mainchan->v2.remwindow += ssh2_pkt_getuint32();
+ c->v2.remwindow += ssh2_pkt_getuint32();
try_send = TRUE;
} else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
char *type;
projects / u / mdw / putty / blobdiff