#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include "putty.h"
#include "tree234.h"
#include "ssh.h"
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
/* uncomment this for packet level debugging */
/* #define DUMP_PACKETS */
#define logevent(s) { logevent(s); \
if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
{ fprintf(stderr, "%s\n", s); fflush(stderr); } }
#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
(s ? sk_close(s), s = NULL : 0), \
connection_fatal msg )
#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
#define SSH1_CMSG_USER 4 /* 0x4 */
#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
#define SSH1_SMSG_SUCCESS 14 /* 0xe */
#define SSH1_SMSG_FAILURE 15 /* 0xf */
#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
#define SSH1_CMSG_EOF 19 /* 0x13 */
#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
#define SSH1_MSG_IGNORE 32 /* 0x20 */
#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
#define SSH1_MSG_DEBUG 36 /* 0x24 */
#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
#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_MSG_DEBUG 4 /* 0x4 */
#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
#define SSH2_MSG_KEXINIT 20 /* 0x14 */
#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
#define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
#define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
#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_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
/*
* Various remote-bug flags.
*/
#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) | \
((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, PKT_BIGNUM };
/* 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))
#define crWaitUntilV(c) do { crReturnV; } while (!(c))
extern char *x11_init(Socket *, char *, void *);
extern void x11_close(Socket);
extern int x11_send(Socket, char *, int);
extern void x11_invent_auth(char *, int, char *, int);
extern void x11_unthrottle(Socket s);
extern void x11_override_throttle(Socket s, int enable);
extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
extern char *pfd_addforward(char *desthost, int destport, int port);
extern void pfd_close(Socket s);
extern int pfd_send(Socket s, char *data, int len);
extern void pfd_confirm(Socket s);
extern void pfd_unthrottle(Socket s);
extern void pfd_override_throttle(Socket s, int enable);
/*
* Buffer management constants. There are several of these for
* various different purposes:
*
* - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
* on a local data stream before we throttle the whole SSH
* connection (in SSH1 only). Throttling the whole connection is
* pretty drastic so we set this high in the hope it won't
* happen very often.
*
* - SSH_MAX_BACKLOG is the amount of backlog that must build up
* on the SSH connection itself before we defensively throttle
* _all_ local data streams. This is pretty drastic too (though
* thankfully unlikely in SSH2 since the window mechanism should
* ensure that the server never has any need to throttle its end
* of the connection), so we set this high as well.
*
* - OUR_V2_WINSIZE is the maximum window size we present on SSH2
* channels.
*/
#define SSH1_BUFFER_LIMIT 32768
#define SSH_MAX_BACKLOG 32768
#define OUR_V2_WINSIZE 16384
/*
* Ciphers for SSH2. We miss out single-DES because it isn't
* supported; also 3DES and Blowfish are both done differently from
* SSH1. (3DES uses outer chaining; Blowfish has the opposite
* endianness and different-sized keys.)
*/
const static struct ssh2_ciphers *ciphers[] = {
&ssh2_aes,
&ssh2_blowfish,
&ssh2_3des,
};
const static struct ssh_kex *kex_algs[] = {
&ssh_diffiehellman_gex,
&ssh_diffiehellman
};
const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
static void nullmac_key(unsigned char *key)
{
}
static void nullmac_generate(unsigned char *blk, int len,
unsigned long seq)
{
}
static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
{
return 1;
}
const static struct ssh_mac ssh_mac_none = {
nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
};
const static struct ssh_mac *macs[] = {
&ssh_sha1, &ssh_md5, &ssh_mac_none
};
const static struct ssh_mac *buggymacs[] = {
&ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
};
static void ssh_comp_none_init(void)
{
}
static int ssh_comp_none_block(unsigned char *block, int len,
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_disable
};
extern const struct ssh_compress ssh_zlib;
const static struct ssh_compress *compressions[] = {
&ssh_zlib, &ssh_comp_none
};
enum { /* channel types */
CHAN_MAINSESSION,
CHAN_X11,
CHAN_AGENT,
CHAN_SOCKDATA,
CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
};
/*
* 2-3-4 tree storing channels.
*/
struct ssh_channel {
unsigned remoteid, localid;
int type;
int closes;
union {
struct ssh1_data_channel {
int throttling;
} v1;
struct ssh2_data_channel {
bufchain outbuffer;
unsigned remwindow, remmaxpkt;
unsigned locwindow;
} v2;
} v;
union {
struct ssh_agent_channel {
unsigned char *message;
unsigned char msglen[4];
int lensofar, totallen;
} a;
struct ssh_x11_channel {
Socket s;
} x11;
struct ssh_pfd_channel {
Socket s;
} pfd;
} u;
};
/*
* 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
* 2 use this structure in different ways, reflecting SSH 2's
* altogether saner approach to port forwarding.
*
* In SSH 1, you arrange a remote forwarding by sending the server
* the remote port number, and the local destination host:port.
* When a connection comes in, the server sends you back that
* host:port pair, and you connect to it. This is a ready-made
* security hole if you're not on the ball: a malicious server
* could send you back _any_ host:port pair, so if you trustingly
* connect to the address it gives you then you've just opened the
* entire inside of your corporate network just by connecting
* through it to a dodgy SSH server. Hence, we must store a list of
* host:port pairs we _are_ trying to forward to, and reject a
* connection request from the server if it's not in the list.
*
* In SSH 2, each side of the connection minds its own business and
* doesn't send unnecessary information to the other. You arrange a
* remote forwarding by sending the server just the remote port
* number. When a connection comes in, the server tells you which
* of its ports was connected to; and _you_ have to remember what
* local host:port pair went with that port number.
*
* Hence: in SSH 1 this structure stores host:port pairs we intend
* to allow connections to, and is indexed by those host:port
* pairs. In SSH 2 it stores a mapping from source port to
* destination host:port pair, and is indexed by source port.
*/
struct ssh_rportfwd {
unsigned sport, dport;
char dhost[256];
};
struct Packet {
long length;
int type;
unsigned char *data;
unsigned char *body;
long savedpos;
long maxlen;
};
static SHA_State exhash, exhashbase;
static Socket s = NULL;
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_mac *csmac = NULL;
static const struct ssh_mac *scmac = NULL;
static const struct ssh_compress *cscomp = NULL;
static const struct ssh_compress *sccomp = 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_line) (const char *prompt, char *str, int maxlen,
int is_pw) = NULL;
static char *savedhost;
static int savedport;
static int ssh_send_ok;
static int ssh_echoing, ssh_editing;
static tree234 *ssh_channels; /* indexed by local id */
static struct ssh_channel *mainchan; /* primary session channel */
static tree234 *ssh_rportfwds;
static enum {
SSH_STATE_PREPACKET,
SSH_STATE_BEFORE_SIZE,
SSH_STATE_INTERMED,
SSH_STATE_SESSION,
SSH_STATE_CLOSED
} ssh_state = SSH_STATE_PREPACKET;
static int size_needed = FALSE, eof_needed = FALSE;
static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
static unsigned char *deferred_send_data = NULL;
static int deferred_len = 0, deferred_size = 0;
/*
* Gross hack: pscp will try to start SFTP but fall back to scp1 if
* that fails. This variable is the means by which scp.c can reach
* into the SSH code and find out which one it got.
*/
int ssh_fallback_cmd = 0;
static int ssh_version;
static int ssh1_throttle_count;
static int ssh_overall_bufsize;
static int ssh_throttled_all;
static int ssh1_stdout_throttling;
static void (*ssh_protocol) (unsigned char *in, int inlen, int ispkt);
static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
static void ssh_size(void);
static void ssh_special(Telnet_Special);
static int ssh2_try_send(struct ssh_channel *c);
static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
int len);
static void ssh_throttle_all(int enable, int bufsize);
static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
static int (*s_rdpkt) (unsigned char **data, int *datalen);
static int ssh_sendbuffer(void);
static struct rdpkt1_state_tag {
long len, pad, biglen, to_read;
unsigned long realcrc, gotcrc;
unsigned char *p;
int i;
int chunk;
} rdpkt1_state;
static struct rdpkt2_state_tag {
long len, pad, payload, packetlen, maclen;
int i;
int cipherblk;
unsigned long incoming_sequence;
} rdpkt2_state;
static int ssh_channelcmp(void *av, void *bv)
{
struct ssh_channel *a = (struct ssh_channel *) av;
struct ssh_channel *b = (struct ssh_channel *) bv;
if (a->localid < b->localid)
return -1;
if (a->localid > b->localid)
return +1;
return 0;
}
static int ssh_channelfind(void *av, void *bv)
{
unsigned *a = (unsigned *) av;
struct ssh_channel *b = (struct ssh_channel *) bv;
if (*a < b->localid)
return -1;
if (*a > b->localid)
return +1;
return 0;
}
static int ssh_rportcmp_ssh1(void *av, void *bv)
{
struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
int i;
if ( (i = strcmp(a->dhost, b->dhost)) != 0)
return i < 0 ? -1 : +1;
if (a->dport > b->dport)
return +1;
if (a->dport < b->dport)
return -1;
return 0;
}
static int ssh_rportcmp_ssh2(void *av, void *bv)
{
struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
if (a->sport > b->sport)
return +1;
if (a->sport < b->sport)
return -1;
return 0;
}
static int alloc_channel_id(void)
{
const unsigned CHANNEL_NUMBER_OFFSET = 256;
unsigned low, high, mid;
int tsize;
struct ssh_channel *c;
/*
* First-fit allocation of channel numbers: always pick the
* lowest unused one. To do this, binary-search using the
* counted B-tree to find the largest channel ID which is in a
* contiguous sequence from the beginning. (Precisely
* everything in that sequence must have ID equal to its tree
* index plus CHANNEL_NUMBER_OFFSET.)
*/
tsize = count234(ssh_channels);
low = -1;
high = tsize;
while (high - low > 1) {
mid = (high + low) / 2;
c = index234(ssh_channels, mid);
if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
low = mid; /* this one is fine */
else
high = mid; /* this one is past it */
}
/*
* Now low points to either -1, or the tree index of the
* largest ID in the initial sequence.
*/
{
unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
assert(NULL == find234(ssh_channels, &i, ssh_channelfind));
}
return low + 1 + CHANNEL_NUMBER_OFFSET;
}
static void c_write(char *buf, int len)
{
if ((flags & FLAG_STDERR)) {
int i;
for (i = 0; i < len; i++)
if (buf[i] != '\r')
fputc(buf[i], stderr);
return;
}
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));
}
/*
* Collect incoming data in the incoming packet buffer.
* Decipher and verify the packet when it is completely read.
* Drop SSH1_MSG_DEBUG and SSH1_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 ssh1_rdpkt(unsigned char **data, int *datalen)
{
struct rdpkt1_state_tag *st = &rdpkt1_state;
crBegin;
next_packet:
pktin.type = 0;
pktin.length = 0;
for (st->i = st->len = 0; st->i < 4; st->i++) {
while ((*datalen) == 0)
crReturn(4 - st->i);
st->len = (st->len << 8) + **data;
(*data)++, (*datalen)--;
}
st->pad = 8 - (st->len % 8);
st->biglen = st->len + st->pad;
pktin.length = st->len - 5;
if (pktin.maxlen < st->biglen) {
pktin.maxlen = st->biglen;
pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) :
srealloc(pktin.data, st->biglen + APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
st->to_read = st->biglen;
st->p = pktin.data;
while (st->to_read > 0) {
st->chunk = st->to_read;
while ((*datalen) == 0)
crReturn(st->to_read);
if (st->chunk > (*datalen))
st->chunk = (*datalen);
memcpy(st->p, *data, st->chunk);
*data += st->chunk;
*datalen -= st->chunk;
st->p += st->chunk;
st->to_read -= st->chunk;
}
if (cipher)
cipher->decrypt(pktin.data, st->biglen);
#ifdef DUMP_PACKETS
debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
dmemdump(pktin.data, st->biglen);
#endif
st->realcrc = crc32(pktin.data, st->biglen - 4);
st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4);
if (st->gotcrc != st->realcrc) {
bombout(("Incorrect CRC received on packet"));
crReturn(0);
}
pktin.body = pktin.data + st->pad + 1;
if (ssh1_compressing) {
unsigned char *decompblk;
int decomplen;
#ifdef DUMP_PACKETS
debug(("Packet payload pre-decompression:\n"));
dmemdump(pktin.body - 1, pktin.length + 1);
#endif
zlib_decompress_block(pktin.body - 1, pktin.length + 1,
&decompblk, &decomplen);
if (pktin.maxlen < st->pad + decomplen) {
pktin.maxlen = st->pad + decomplen;
pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA);
pktin.body = pktin.data + st->pad + 1;
if (!pktin.data)
fatalbox("Out of memory");
}
memcpy(pktin.body - 1, decompblk, decomplen);
sfree(decompblk);
pktin.length = decomplen - 1;
#ifdef DUMP_PACKETS
debug(("Packet payload post-decompression:\n"));
dmemdump(pktin.body - 1, pktin.length + 1);
#endif
}
if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
pktin.type == SSH1_SMSG_STDERR_DATA ||
pktin.type == SSH1_MSG_DEBUG ||
pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
long strlen = GET_32BIT(pktin.body);
if (strlen + 4 != pktin.length) {
bombout(("Received data packet with bogus string length"));
crReturn(0);
}
}
pktin.type = pktin.body[-1];
if (pktin.type == SSH1_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 == SSH1_MSG_IGNORE) {
/* do nothing */
goto next_packet;
}
if (pktin.type == SSH1_MSG_DISCONNECT) {
/* log reason code in disconnect message */
char buf[256];
unsigned msglen = GET_32BIT(pktin.body);
unsigned 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);
bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
crReturn(0);
}
crFinish(0);
}
static int ssh2_rdpkt(unsigned char **data, int *datalen)
{
struct rdpkt2_state_tag *st = &rdpkt2_state;
crBegin;
next_packet:
pktin.type = 0;
pktin.length = 0;
if (sccipher)
st->cipherblk = sccipher->blksize;
else
st->cipherblk = 8;
if (st->cipherblk < 8)
st->cipherblk = 8;
if (pktin.maxlen < st->cipherblk) {
pktin.maxlen = st->cipherblk;
pktin.data =
(pktin.data ==
NULL ? smalloc(st->cipherblk +
APIEXTRA) : srealloc(pktin.data,
st->cipherblk +
APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
/*
* Acquire and decrypt the first block of the packet. This will
* contain the length and padding details.
*/
for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
while ((*datalen) == 0)
crReturn(st->cipherblk - st->i);
pktin.data[st->i] = *(*data)++;
(*datalen)--;
}
if (sccipher)
sccipher->decrypt(pktin.data, st->cipherblk);
/*
* Now get the length and padding figures.
*/
st->len = GET_32BIT(pktin.data);
st->pad = pktin.data[4];
/*
* This enables us to deduce the payload length.
*/
st->payload = st->len - st->pad - 1;
pktin.length = st->payload + 5;
/*
* So now we can work out the total packet length.
*/
st->packetlen = st->len + 4;
st->maclen = scmac ? scmac->len : 0;
/*
* Adjust memory allocation if packet is too big.
*/
if (pktin.maxlen < st->packetlen + st->maclen) {
pktin.maxlen = st->packetlen + st->maclen;
pktin.data =
(pktin.data ==
NULL ? smalloc(pktin.maxlen + APIEXTRA) : srealloc(pktin.data,
pktin.maxlen
+
APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
/*
* Read and decrypt the remainder of the packet.
*/
for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
st->i++) {
while ((*datalen) == 0)
crReturn(st->packetlen + st->maclen - st->i);
pktin.data[st->i] = *(*data)++;
(*datalen)--;
}
/* Decrypt everything _except_ the MAC. */
if (sccipher)
sccipher->decrypt(pktin.data + st->cipherblk,
st->packetlen - st->cipherblk);
#ifdef DUMP_PACKETS
debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
dmemdump(pktin.data, st->packetlen);
#endif
/*
* Check the MAC.
*/
if (scmac
&& !scmac->verify(pktin.data, st->len + 4,
st->incoming_sequence)) {
bombout(("Incorrect MAC received on packet"));
crReturn(0);
}
st->incoming_sequence++; /* whether or not we MACed */
/*
* Decompress packet payload.
*/
{
unsigned char *newpayload;
int newlen;
if (sccomp && sccomp->decompress(pktin.data + 5, pktin.length - 5,
&newpayload, &newlen)) {
if (pktin.maxlen < newlen + 5) {
pktin.maxlen = newlen + 5;
pktin.data =
(pktin.data ==
NULL ? smalloc(pktin.maxlen +
APIEXTRA) : srealloc(pktin.data,
pktin.maxlen +
APIEXTRA));
if (!pktin.data)
fatalbox("Out of memory");
}
pktin.length = 5 + newlen;
memcpy(pktin.data + 5, newpayload, newlen);
#ifdef DUMP_PACKETS
debug(("Post-decompression payload:\n"));
dmemdump(pktin.data + 5, newlen);
#endif
sfree(newpayload);
}
}
pktin.savedpos = 6;
pktin.type = pktin.data[5];
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);
unsigned msglen = GET_32BIT(pktin.data + 10);
unsigned 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);
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);
}
static void ssh1_pktout_size(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 ? smalloc(biglen + 12) :
srealloc(pktout.data, biglen + 12));
#else
pktout.data = (pktout.data == NULL ? smalloc(biglen + 4) :
srealloc(pktout.data, biglen + 4));
#endif
if (!pktout.data)
fatalbox("Out of memory");
}
pktout.body = pktout.data + 4 + pad + 1;
}
static void s_wrpkt_start(int type, int len)
{
ssh1_pktout_size(len);
pktout.type = type;
}
static int s_wrpkt_prepare(void)
{
int pad, len, biglen, i;
unsigned long crc;
pktout.body[-1] = pktout.type;
#ifdef DUMP_PACKETS
debug(("Packet payload pre-compression:\n"));
dmemdump(pktout.body - 1, pktout.length + 1);
#endif
if (ssh1_compressing) {
unsigned char *compblk;
int complen;
zlib_compress_block(pktout.body - 1, pktout.length + 1,
&compblk, &complen);
ssh1_pktout_size(complen - 1);
memcpy(pktout.body - 1, compblk, complen);
sfree(compblk);
#ifdef DUMP_PACKETS
debug(("Packet payload post-compression:\n"));
dmemdump(pktout.body - 1, pktout.length + 1);
#endif
}
len = pktout.length + 5; /* type and CRC */
pad = 8 - (len % 8);
biglen = len + pad;
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);
#ifdef DUMP_PACKETS
debug(("Sending packet len=%d\n", biglen + 4));
dmemdump(pktout.data, biglen + 4);
#endif
if (cipher)
cipher->encrypt(pktout.data + 4, biglen);
return biglen + 4;
}
static void s_wrpkt(void)
{
int len, backlog;
len = s_wrpkt_prepare();
backlog = sk_write(s, pktout.data, len);
if (backlog > SSH_MAX_BACKLOG)
ssh_throttle_all(1, backlog);
}
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.
*/
static void construct_packet(int pkttype, va_list ap1, va_list ap2)
{
unsigned char *p, *argp, argchar;
unsigned long argint;
int pktlen, argtype, arglen;
Bignum bn;
pktlen = 0;
while ((argtype = va_arg(ap1, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
(void) va_arg(ap1, int);
pktlen += 4;
break;
case PKT_CHAR:
(void) va_arg(ap1, char);
pktlen++;
break;
case PKT_DATA:
(void) va_arg(ap1, unsigned char *);
arglen = va_arg(ap1, int);
pktlen += arglen;
break;
case PKT_STR:
argp = va_arg(ap1, unsigned char *);
arglen = strlen(argp);
pktlen += 4 + arglen;
break;
case PKT_BIGNUM:
bn = va_arg(ap1, Bignum);
pktlen += ssh1_bignum_length(bn);
break;
default:
assert(0);
}
}
s_wrpkt_start(pkttype, pktlen);
p = pktout.body;
while ((argtype = va_arg(ap2, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
argint = va_arg(ap2, int);
PUT_32BIT(p, argint);
p += 4;
break;
case PKT_CHAR:
argchar = va_arg(ap2, unsigned char);
*p = argchar;
p++;
break;
case PKT_DATA:
argp = va_arg(ap2, unsigned char *);
arglen = va_arg(ap2, int);
memcpy(p, argp, arglen);
p += arglen;
break;
case PKT_STR:
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(ap2, Bignum);
p += ssh1_write_bignum(p, bn);
break;
}
}
}
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;
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;
}
/*
* Utility routines for putting an SSH-protocol `string' and
* `uint32' into a SHA state.
*/
#include <stdio.h>
static void sha_string(SHA_State * s, void *str, int len)
{
unsigned char lenblk[4];
PUT_32BIT(lenblk, len);
SHA_Bytes(s, lenblk, 4);
SHA_Bytes(s, str, len);
}
static void sha_uint32(SHA_State * s, unsigned i)
{
unsigned char intblk[4];
PUT_32BIT(intblk, i);
SHA_Bytes(s, intblk, 4);
}
/*
* SSH2 packet construction functions.
*/
static void ssh2_pkt_ensure(int length)
{
if (pktout.maxlen < length) {
pktout.maxlen = length + 256;
pktout.data =
(pktout.data ==
NULL ? smalloc(pktout.maxlen +
APIEXTRA) : srealloc(pktout.data,
pktout.maxlen +
APIEXTRA));
if (!pktout.data)
fatalbox("Out of memory");
}
}
static void ssh2_pkt_adddata(void *data, int len)
{
pktout.length += len;
ssh2_pkt_ensure(pktout.length);
memcpy(pktout.data + pktout.length - len, data, len);
}
static void ssh2_pkt_addbyte(unsigned char byte)
{
ssh2_pkt_adddata(&byte, 1);
}
static void ssh2_pkt_init(int pkt_type)
{
pktout.length = 5;
ssh2_pkt_addbyte((unsigned char) pkt_type);
}
static void ssh2_pkt_addbool(unsigned char value)
{
ssh2_pkt_adddata(&value, 1);
}
static void ssh2_pkt_adduint32(unsigned long value)
{
unsigned char x[4];
PUT_32BIT(x, value);
ssh2_pkt_adddata(x, 4);
}
static void ssh2_pkt_addstring_start(void)
{
ssh2_pkt_adduint32(0);
pktout.savedpos = pktout.length;
}
static void ssh2_pkt_addstring_str(char *data)
{
ssh2_pkt_adddata(data, strlen(data));
PUT_32BIT(pktout.data + pktout.savedpos - 4,
pktout.length - pktout.savedpos);
}
static void ssh2_pkt_addstring_data(char *data, int len)
{
ssh2_pkt_adddata(data, len);
PUT_32BIT(pktout.data + pktout.savedpos - 4,
pktout.length - pktout.savedpos);
}
static void ssh2_pkt_addstring(char *data)
{
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_str(data);
}
static char *ssh2_mpint_fmt(Bignum b, int *len)
{
unsigned char *p;
int i, n = (bignum_bitcount(b) + 7) / 8;
p = smalloc(n + 1);
if (!p)
fatalbox("out of memory");
p[0] = 0;
for (i = 1; i <= n; i++)
p[i] = bignum_byte(b, n - i);
i = 0;
while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
i++;
memmove(p, p + i, n + 1 - i);
*len = n + 1 - i;
return p;
}
static void ssh2_pkt_addmp(Bignum b)
{
unsigned char *p;
int len;
p = ssh2_mpint_fmt(b, &len);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(p, len);
sfree(p);
}
/*
* Construct an SSH2 final-form packet: compress it, encrypt it,
* put the MAC on it. Final packet, ready to be sent, is stored in
* pktout.data. Total length is returned.
*/
static int ssh2_pkt_construct(void)
{
int cipherblk, maclen, padding, i;
static unsigned long outgoing_sequence = 0;
/*
* Compress packet payload.
*/
#ifdef DUMP_PACKETS
debug(("Pre-compression payload:\n"));
dmemdump(pktout.data + 5, pktout.length - 5);
#endif
{
unsigned char *newpayload;
int newlen;
if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5,
&newpayload, &newlen)) {
pktout.length = 5;
ssh2_pkt_adddata(newpayload, newlen);
sfree(newpayload);
}
}
/*
* Add padding. At least four bytes, and must also bring total
* length (minus MAC) up to a multiple of the block size.
*/
cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
padding = 4;
padding +=
(cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
maclen = csmac ? csmac->len : 0;
ssh2_pkt_ensure(pktout.length + padding + maclen);
pktout.data[4] = padding;
for (i = 0; i < padding; i++)
pktout.data[pktout.length + i] = random_byte();
PUT_32BIT(pktout.data, pktout.length + padding - 4);
if (csmac)
csmac->generate(pktout.data, pktout.length + padding,
outgoing_sequence);
outgoing_sequence++; /* whether or not we MACed */
#ifdef DUMP_PACKETS
debug(("Sending packet len=%d\n", pktout.length + padding));
dmemdump(pktout.data, pktout.length + padding);
#endif
if (cscipher)
cscipher->encrypt(pktout.data, pktout.length + padding);
/* Ready-to-send packet starts at pktout.data. We return length. */
return pktout.length + padding + maclen;
}
/*
* Construct and send an SSH2 packet immediately.
*/
static void ssh2_pkt_send(void)
{
int len;
int backlog;
len = ssh2_pkt_construct();
backlog = sk_write(s, pktout.data, len);
if (backlog > SSH_MAX_BACKLOG)
ssh_throttle_all(1, backlog);
}
/*
* Construct an SSH2 packet and add it to a deferred data block.
* Useful for sending multiple packets in a single sk_write() call,
* to prevent a traffic-analysing listener from being able to work
* out the length of any particular packet (such as the password
* packet).
*
* Note that because SSH2 sequence-numbers its packets, this can
* NOT be used as an m4-style `defer' allowing packets to be
* constructed in one order and sent in another.
*/
static void ssh2_pkt_defer(void)
{
int len = ssh2_pkt_construct();
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;
}
/*
* Send the whole deferred data block constructed by
* ssh2_pkt_defer() or SSH1's defer_packet().
*/
static void ssh_pkt_defersend(void)
{
int backlog;
backlog = sk_write(s, deferred_send_data, deferred_len);
deferred_len = deferred_size = 0;
sfree(deferred_send_data);
deferred_send_data = NULL;
if (backlog > SSH_MAX_BACKLOG)
ssh_throttle_all(1, backlog);
}
#if 0
void bndebug(char *string, Bignum b)
{
unsigned char *p;
int i, len;
p = ssh2_mpint_fmt(b, &len);
debug(("%s", string));
for (i = 0; i < len; i++)
debug((" %02x", p[i]));
debug(("\n"));
sfree(p);
}
#endif
static void sha_mpint(SHA_State * s, Bignum b)
{
unsigned char *p;
int len;
p = ssh2_mpint_fmt(b, &len);
sha_string(s, p, len);
sfree(p);
}
/*
* SSH2 packet decode functions.
*/
static unsigned long ssh2_pkt_getuint32(void)
{
unsigned long value;
if (pktin.length - pktin.savedpos < 4)
return 0; /* arrgh, no way to decline (FIXME?) */
value = GET_32BIT(pktin.data + pktin.savedpos);
pktin.savedpos += 4;
return value;
}
static int ssh2_pkt_getbool(void)
{
unsigned long value;
if (pktin.length - pktin.savedpos < 1)
return 0; /* arrgh, no way to decline (FIXME?) */
value = pktin.data[pktin.savedpos] != 0;
pktin.savedpos++;
return value;
}
static void ssh2_pkt_getstring(char **p, int *length)
{
*p = NULL;
if (pktin.length - pktin.savedpos < 4)
return;
*length = GET_32BIT(pktin.data + pktin.savedpos);
pktin.savedpos += 4;
if (pktin.length - pktin.savedpos < *length)
return;
*p = pktin.data + pktin.savedpos;
pktin.savedpos += *length;
}
static Bignum ssh2_pkt_getmp(void)
{
char *p;
int length;
Bignum b;
ssh2_pkt_getstring(&p, &length);
if (!p)
return NULL;
if (p[0] & 0x80) {
bombout(("internal error: Can't handle negative mpints"));
return NULL;
}
b = bignum_from_bytes(p, length);
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") || !strcmp(imp, "Cisco-1.25")) {
/*
* 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 (!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)) {
/*
* 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 int vslen;
static char version[10];
static char *vstring;
static int vstrsize;
static char *vlog;
static int i;
crBegin;
/* Search for the string "SSH-" in the input. */
i = 0;
while (1) {
static const int transS[] = { 1, 2, 2, 1 };
static const int transH[] = { 0, 0, 3, 0 };
static const int transminus[] = { 0, 0, 0, -1 };
if (c == 'S')
i = transS[i];
else if (c == 'H')
i = transH[i];
else if (c == '-')
i = transminus[i];
else
i = 0;
if (i < 0)
break;
crReturn(1); /* get another character */
}
vstrsize = 16;
vstring = smalloc(vstrsize);
strcpy(vstring, "SSH-");
vslen = 4;
i = 0;
while (1) {
crReturn(1); /* get another char */
if (vslen >= vstrsize - 1) {
vstrsize += 16;
vstring = srealloc(vstring, vstrsize);
}
vstring[vslen++] = 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;
}
ssh_agentfwd_enabled = FALSE;
rdpkt2_state.incoming_sequence = 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);
logevent(vlog);
ssh_detect_bugs(vstring);
sfree(vlog);
/*
* Server version "1.99" means we can choose whether we use v1
* or v2 protocol. Choice is based on cfg.sshprot.
*/
if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
/*
* This is a v2 server. Begin v2 protocol.
*/
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(vlog, "We claim version: %s", verstring);
logevent(vlog);
strcat(verstring, "\n");
logevent("Using SSH protocol version 2");
sk_write(s, verstring, strlen(verstring));
ssh_protocol = ssh2_protocol;
ssh_version = 2;
s_rdpkt = ssh2_rdpkt;
} else {
/*
* This is a v1 server. Begin v1 protocol.
*/
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, verstring, strlen(verstring));
ssh_protocol = ssh1_protocol;
ssh_version = 1;
s_rdpkt = ssh1_rdpkt;
}
ssh_state = SSH_STATE_BEFORE_SIZE;
sfree(vstring);
crFinish(0);
}
static void ssh_gotdata(unsigned char *data, int datalen)
{
crBegin;
/*
* To begin with, feed the characters one by one to the
* protocol initialisation / selection function do_ssh_init().
* When that returns 0, we're done with the initial greeting
* exchange and can move on to packet discipline.
*/
while (1) {
int ret;
if (datalen == 0)
crReturnV; /* more data please */
ret = do_ssh_init(*data);
data++;
datalen--;
if (ret == 0)
break;
}
/*
* We emerge from that loop when the initial negotiation is
* over and we have selected an s_rdpkt function. Now pass
* everything to s_rdpkt, and then pass the resulting packets
* to the proper protocol handler.
*/
if (datalen == 0)
crReturnV;
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;
}
}
}
crReturnV;
}
crFinishV;
}
static int ssh_closing(Plug plug, char *error_msg, int error_code,
int calling_back)
{
ssh_state = SSH_STATE_CLOSED;
if (s) {
sk_close(s);
s = NULL;
}
if (error_msg) {
/* A socket error has occurred. */
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) {
sk_close(s);
s = NULL;
}
return 0;
}
return 1;
}
static void ssh_sent(Plug plug, int bufsize)
{
/*
* If the send backlog on the SSH socket itself clears, we
* should unthrottle the whole world if it was throttled.
*/
if (bufsize < SSH_MAX_BACKLOG)
ssh_throttle_all(0, bufsize);
}
/*
* Connect to specified host and port.
* Returns an error message, or NULL on success.
* Also places the canonical host name into `realhost'. It must be
* freed by the caller.
*/
static char *connect_to_host(char *host, int port, char **realhost)
{
static struct plug_function_table fn_table = {
ssh_closing,
ssh_receive,
ssh_sent,
NULL
}, *fn_table_ptr = &fn_table;
SockAddr addr;
char *err;
#ifdef FWHACK
char *FWhost;
int FWport;
#endif
savedhost = smalloc(1 + strlen(host));
if (!savedhost)
fatalbox("Out of memory");
strcpy(savedhost, host);
if (port < 0)
port = 22; /* default ssh port */
savedport = port;
#ifdef FWHACK
FWhost = host;
FWport = port;
host = FWSTR;
port = 23;
#endif
/*
* 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;
#ifdef FWHACK
*realhost = strdup(FWhost);
#endif
/*
* 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;
#ifdef FWHACK
sk_write(s, "connect ", 8);
sk_write(s, FWhost, strlen(FWhost));
{
char buf[20];
sprintf(buf, " %d\n", FWport);
sk_write(s, buf, strlen(buf));
}
#endif
return NULL;
}
/*
* Throttle or unthrottle the SSH connection.
*/
static void ssh1_throttle(int adjust)
{
int old_count = ssh1_throttle_count;
ssh1_throttle_count += adjust;
assert(ssh1_throttle_count >= 0);
if (ssh1_throttle_count && !old_count) {
sk_set_frozen(s, 1);
} else if (!ssh1_throttle_count && old_count) {
sk_set_frozen(s, 0);
}
}
/*
* Throttle or unthrottle _all_ local data streams (for when sends
* on the SSH connection itself back up).
*/
static void ssh_throttle_all(int enable, int bufsize)
{
int i;
struct ssh_channel *c;
if (enable == ssh_throttled_all)
return;
ssh_throttled_all = enable;
ssh_overall_bufsize = bufsize;
if (!ssh_channels)
return;
for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) {
switch (c->type) {
case CHAN_MAINSESSION:
/*
* This is treated separately, outside the switch.
*/
break;
case CHAN_X11:
x11_override_throttle(c->u.x11.s, enable);
break;
case CHAN_AGENT:
/* Agent channels require no buffer management. */
break;
case CHAN_SOCKDATA:
pfd_override_throttle(c->u.x11.s, enable);
break;
}
}
}
/*
* Handle the key exchange and user authentication phases.
*/
static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
{
int i, j;
static int len;
static 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;
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];
crBegin;
if (!ispkt)
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
bombout(("Public key packet not received"));
crReturn(0);
}
logevent("Received public keys");
memcpy(cookie, pktin.body, 8);
i = makekey(pktin.body + 8, &servkey, &keystr1, 0);
j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0);
/*
* Log the host key fingerprint.
*/
{
char logmsg[80];
logevent("Host key fingerprint is:");
strcpy(logmsg, " ");
hostkey.comment = NULL;
rsa_fingerprint(logmsg + strlen(logmsg),
sizeof(logmsg) - strlen(logmsg), &hostkey);
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);
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 = smalloc(len);
if (!rsabuf)
fatalbox("Out of memory");
/*
* Verify the host key.
*/
{
/*
* First format the key into a string.
*/
int len = rsastr_len(&hostkey);
char fingerprint[100];
char *keystr = smalloc(len);
if (!keystr)
fatalbox("Out of memory");
rsastr_fmt(keystr, &hostkey);
rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
verify_ssh_host_key(savedhost, savedport, "rsa", keystr,
fingerprint);
sfree(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");
{
int cipher_chosen = 0, warn = 0;
char *cipher_string = NULL;
for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
int next_cipher = cfg.ssh_cipherlist[i];
if (next_cipher == CIPHER_WARN) {
/* If/when we choose a cipher, warn about it */
warn = 1;
} else if (next_cipher == CIPHER_AES) {
/* XXX Probably don't need to mention this. */
logevent("AES not supported in SSH1, skipping");
} else {
switch (next_cipher) {
case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES;
cipher_string = "3DES"; break;
case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH;
cipher_string = "Blowfish"; break;
case CIPHER_DES: cipher_type = SSH_CIPHER_DES;
cipher_string = "single-DES"; break;
}
if (supported_ciphers_mask & (1 << cipher_type))
cipher_chosen = 1;
}
}
if (!cipher_chosen) {
if ((supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
bombout(("Server violates SSH 1 protocol by not "
"supporting 3DES encryption"));
else
/* shouldn't happen */
bombout(("No supported ciphers found"));
crReturn(0);
}
/* Warn about chosen cipher if necessary. */
if (warn)
askcipher(cipher_string, 0);
}
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(SSH1_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, ssh1_local_protoflags, PKT_END);
logevent("Trying to enable encryption...");
sfree(rsabuf);
cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des;
cipher->sesskey(session_key);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(("Encryption not successfully enabled"));
crReturn(0);
}
logevent("Successfully started encryption");
fflush(stdout);
{
static int pos = 0;
static char c;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
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 < sizeof(username)-1) {
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';
}
send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
{
char userlog[22 + sizeof(username)];
sprintf(userlog, "Sent username \"%s\"", username);
logevent(userlog);
if (flags & FLAG_INTERACTIVE &&
(!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
strcat(userlog, "\r\n");
c_write_str(userlog);
}
}
}
crWaitUntil(ispkt);
tried_publickey = 0;
tis_auth_refused = ccard_auth_refused = 0;
while (pktin.type == SSH1_SMSG_FAILURE) {
static char password[100];
static char prompt[200];
static int pos;
static char c;
static int pwpkt_type;
pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
if (agent_exists()) {
/*
* Attempt RSA authentication using Pageant.
*/
static unsigned char request[5], *response, *p;
static int responselen;
static int i, nkeys;
static int authed = FALSE;
void *r;
logevent("Pageant is running. Requesting keys.");
/* Request the keys held by the agent. */
PUT_32BIT(request, 1);
request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
agent_query(request, 5, &r, &responselen);
response = (unsigned char *) r;
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 SSH1 keys", nkeys);
logevent(buf);
}
for (i = 0; i < nkeys; i++) {
static struct RSAKey key;
static Bignum challenge;
static char *commentp;
static int commentlen;
{
char buf[64];
sprintf(buf, "Trying Pageant key #%d", i);
logevent(buf);
}
p += 4;
p += ssh1_read_bignum(p, &key.exponent);
p += ssh1_read_bignum(p, &key.modulus);
commentlen = GET_32BIT(p);
p += 4;
commentp = p;
p += commentlen;
send_packet(SSH1_CMSG_AUTH_RSA,
PKT_BIGNUM, key.modulus, PKT_END);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
logevent("Key refused");
continue;
}
logevent("Received RSA challenge");
ssh1_read_bignum(pktin.body, &challenge);
{
char *agentreq, *q, *ret;
void *vret;
int len, retlen;
len = 1 + 4; /* message type, bit count */
len += ssh1_bignum_length(key.exponent);
len += ssh1_bignum_length(key.modulus);
len += ssh1_bignum_length(challenge);
len += 16; /* session id */
len += 4; /* response format */
agentreq = smalloc(4 + len);
PUT_32BIT(agentreq, len);
q = agentreq + 4;
*q++ = SSH1_AGENTC_RSA_CHALLENGE;
PUT_32BIT(q, bignum_bitcount(key.modulus));
q += 4;
q += ssh1_write_bignum(q, key.exponent);
q += ssh1_write_bignum(q, key.modulus);
q += ssh1_write_bignum(q, challenge);
memcpy(q, session_id, 16);
q += 16;
PUT_32BIT(q, 1); /* response format */
agent_query(agentreq, len + 4, &vret, &retlen);
ret = vret;
sfree(agentreq);
if (ret) {
if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
logevent("Sending Pageant's response");
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, ret + 5, 16,
PKT_END);
sfree(ret);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_SUCCESS) {
logevent
("Pageant's response accepted");
if (flags & FLAG_VERBOSE) {
c_write_str
("Authenticated using RSA key \"");
c_write(commentp, commentlen);
c_write_str("\" from agent\r\n");
}
authed = TRUE;
} else
logevent
("Pageant's response not accepted");
} else {
logevent
("Pageant failed to answer challenge");
sfree(ret);
}
} else {
logevent("No reply received from Pageant");
}
}
freebn(key.exponent);
freebn(key.modulus);
freebn(challenge);
if (authed)
break;
}
}
if (authed)
break;
}
if (*cfg.keyfile && !tried_publickey)
pwpkt_type = SSH1_CMSG_AUTH_RSA;
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);
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
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) |
(pktin.body[2] << 8) |
(pktin.body[3]));
logevent("Received TIS challenge");
if (challengelen > sizeof(prompt) - 1)
challengelen = sizeof(prompt) - 1; /* prevent overrun */
memcpy(prompt, pktin.body + 4, challengelen);
/* Prompt heuristic comes from OpenSSH */
strncpy(prompt + challengelen,
memchr(prompt, '\n', challengelen) ?
"": "\r\nResponse: ",
(sizeof prompt) - challengelen);
prompt[(sizeof prompt) - 1] = '\0';
}
}
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);
crWaitUntil(ispkt);
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) |
(pktin.body[2] << 8) |
(pktin.body[3]));
logevent("Received CryptoCard challenge");
if (challengelen > sizeof(prompt) - 1)
challengelen = sizeof(prompt) - 1; /* prevent overrun */
memcpy(prompt, pktin.body + 4, challengelen);
strncpy(prompt + challengelen,
memchr(prompt, '\n', challengelen) ?
"" : "\r\nResponse: ",
sizeof(prompt) - challengelen);
prompt[sizeof(prompt) - 1] = '\0';
}
}
if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
sprintf(prompt, "%.90s@%.90s's password: ",
username, savedhost);
}
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
char *comment = NULL;
if (flags & FLAG_VERBOSE)
c_write_str("Trying public key authentication.\r\n");
if (!rsakey_encrypted(cfg.keyfile, &comment)) {
if (flags & FLAG_VERBOSE)
c_write_str("No passphrase required.\r\n");
goto tryauth;
}
sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
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)) {
/*
* get_line failed to get a password (for example
* because one was supplied on the command line
* which has already failed to work). Terminate.
*/
send_packet(SSH1_MSG_DISCONNECT,
PKT_STR, "No more passwords available to try",
PKT_END);
connection_fatal("Unable to authenticate");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
}
} else {
/* 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) {
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 (pos < sizeof(password)-1)
password[pos++] = c;
break;
}
}
c_write_str("\r\n");
}
tryauth:
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
/*
* Try public key authentication with the specified
* key file.
*/
static struct RSAKey pubkey;
static Bignum challenge, response;
static int i;
static unsigned char buffer[32];
tried_publickey = 1;
i = loadrsakey(cfg.keyfile, &pubkey, password);
if (i == 0) {
c_write_str("Couldn't load private key from ");
c_write_str(cfg.keyfile);
c_write_str(".\r\n");
continue; /* go and try password */
}
if (i == -1) {
c_write_str("Wrong passphrase.\r\n");
tried_publickey = 0;
continue; /* try again */
}
/*
* Send a public key attempt.
*/
send_packet(SSH1_CMSG_AUTH_RSA,
PKT_BIGNUM, pubkey.modulus, PKT_END);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
c_write_str("Server refused our public key.\r\n");
continue; /* go and try password */
}
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
bombout(("Bizarre response to offer of public key"));
crReturn(0);
}
ssh1_read_bignum(pktin.body, &challenge);
response = rsadecrypt(challenge, &pubkey);
freebn(pubkey.private_exponent); /* burn the evidence */
for (i = 0; i < 32; i++) {
buffer[i] = bignum_byte(response, 31 - i);
}
MD5Init(&md5c);
MD5Update(&md5c, buffer, 32);
MD5Update(&md5c, session_id, 16);
MD5Final(buffer, &md5c);
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, buffer, 16, PKT_END);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
c_write_str
("Failed to authenticate with our public key.\r\n");
continue; /* go and try password */
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(
("Bizarre response to RSA authentication response"));
crReturn(0);
}
break; /* we're through! */
} else {
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.
*
* 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)) {
/*
* The server can deal with SSH1_MSG_IGNORE, so
* we can use the primary defence.
*/
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);
}
}
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);
}
}
logevent("Sent password");
memset(password, 0, strlen(password));
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
c_write_str("Access denied\r\n");
logevent("Authentication refused");
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
logevent("Received disconnect request");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(("Strange packet received, type %d", pktin.type));
crReturn(0);
}
}
logevent("Authentication successful");
crFinish(1);
}
void sshfwd_close(struct ssh_channel *c)
{
if (c && !c->closes) {
if (ssh_version == 1) {
send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_send();
}
c->closes = 1;
if (c->type == CHAN_X11) {
c->u.x11.s = NULL;
logevent("Forwarded X11 connection terminated");
} else if (c->type == CHAN_SOCKDATA) {
c->u.pfd.s = NULL;
logevent("Forwarded port closed");
}
}
}
int sshfwd_write(struct ssh_channel *c, char *buf, int len)
{
if (ssh_version == 1) {
send_packet(SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKT_INT, len, PKT_DATA, buf, len, PKT_END);
/*
* In SSH1 we can return 0 here - implying that forwarded
* connections are never individually throttled - because
* the only circumstance that can cause throttling will be
* the whole SSH connection backing up, in which case
* _everything_ will be throttled as a whole.
*/
return 0;
} else {
ssh2_add_channel_data(c, buf, len);
return ssh2_try_send(c);
}
}
void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
{
if (ssh_version == 1) {
if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
c->v.v1.throttling = 0;
ssh1_throttle(-1);
}
} else {
ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
}
}
static void ssh1_protocol(unsigned char *in, int inlen, int ispkt)
{
crBegin;
random_init();
while (!do_ssh1_login(in, inlen, ispkt)) {
crReturnV;
}
if (ssh_state == SSH_STATE_CLOSED)
crReturnV;
if (cfg.agentfwd && agent_exists()) {
logevent("Requesting agent forwarding");
send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
do {
crReturnV;
} while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS
&& pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
logevent("Agent forwarding refused");
} else {
logevent("Agent forwarding enabled");
ssh_agentfwd_enabled = TRUE;
}
}
if (cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 forwarding");
x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
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"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
logevent("X11 forwarding refused");
} else {
logevent("X11 forwarding enabled");
ssh_X11_fwd_enabled = TRUE;
}
}
{
char type, *e;
int n;
int sport,dport;
char sports[256], dports[256], host[256];
char buf[1024];
ssh_rportfwds = newtree234(ssh_rportcmp_ssh1);
/* Add port forwardings. */
e = cfg.portfwd;
while (*e) {
type = *e++;
n = 0;
while (*e && *e != '\t')
sports[n++] = *e++;
sports[n] = 0;
if (*e == '\t')
e++;
n = 0;
while (*e && *e != ':')
host[n++] = *e++;
host[n] = 0;
if (*e == ':')
e++;
n = 0;
while (*e)
dports[n++] = *e++;
dports[n] = 0;
e++;
dport = atoi(dports);
sport = atoi(sports);
if (sport && dport) {
if (type == 'L') {
pfd_addforward(host, dport, sport);
sprintf(buf, "Local port %d forwarding to %s:%d",
sport, host, dport);
logevent(buf);
} else {
struct ssh_rportfwd *pf;
pf = smalloc(sizeof(*pf));
strcpy(pf->dhost, host);
pf->dport = dport;
if (add234(ssh_rportfwds, pf) != pf) {
sprintf(buf,
"Duplicate remote port forwarding to %s:%d",
host, dport);
logevent(buf);
sfree(pf);
} else {
sprintf(buf, "Requesting remote port %d forward to %s:%d",
sport, host, dport);
logevent(buf);
send_packet(SSH1_CMSG_PORT_FORWARD_REQUEST,
PKT_INT, sport,
PKT_STR, host,
PKT_INT, dport,
PKT_END);
}
}
}
}
}
if (!cfg.nopty) {
send_packet(SSH1_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 != SSH1_SMSG_SUCCESS
&& pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
c_write_str("Server refused to allocate pty\r\n");
ssh_editing = ssh_echoing = 1;
}
logevent("Allocated pty");
} else {
ssh_editing = ssh_echoing = 1;
}
if (cfg.compression) {
send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
do {
crReturnV;
} while (!ispkt);
if (pktin.type != SSH1_SMSG_SUCCESS
&& pktin.type != SSH1_SMSG_FAILURE) {
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
c_write_str("Server refused to compress\r\n");
}
logevent("Started compression");
ssh1_compressing = TRUE;
zlib_compress_init();
zlib_decompress_init();
}
/*
* Start the shell or command.
*
* Special case: if the first-choice command is an SSH2
* subsystem (hence not usable here) and the second choice
* exists, we fall straight back to that.
*/
{
char *cmd = cfg.remote_cmd_ptr;
if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
cmd = cfg.remote_cmd_ptr2;
ssh_fallback_cmd = TRUE;
}
if (*cmd)
send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
else
send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
logevent("Started session");
}
ssh_state = SSH_STATE_SESSION;
if (size_needed)
ssh_size();
if (eof_needed)
ssh_special(TS_EOF);
ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */
ssh_send_ok = 1;
ssh_channels = newtree234(ssh_channelcmp);
while (1) {
crReturnV;
if (ispkt) {
if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
pktin.type == SSH1_SMSG_STDERR_DATA) {
long len = GET_32BIT(pktin.body);
int bufsize =
from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
pktin.body + 4, len);
if (!ssh1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
ssh1_stdout_throttling = 1;
ssh1_throttle(+1);
}
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
ssh_state = SSH_STATE_CLOSED;
logevent("Received disconnect request");
crReturnV;
} else if (pktin.type == SSH1_SMSG_X11_OPEN) {
/* Remote side is trying to open a channel to talk to our
* X-Server. Give them back a local channel number. */
struct ssh_channel *c;
logevent("Received X11 connect request");
/* Refuse if X11 forwarding is disabled. */
if (!ssh_X11_fwd_enabled) {
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body), PKT_END);
logevent("Rejected X11 connect request");
} else {
c = smalloc(sizeof(struct ssh_channel));
if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) {
logevent("opening X11 forward connection failed");
sfree(c);
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body),
PKT_END);
} else {
logevent
("opening X11 forward connection succeeded");
c->remoteid = GET_32BIT(pktin.body);
c->localid = alloc_channel_id();
c->closes = 0;
c->v.v1.throttling = 0;
c->type = CHAN_X11; /* identify channel type */
add234(ssh_channels, c);
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT,
c->localid, PKT_END);
logevent("Opened X11 forward channel");
}
}
} else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
/* Remote side is trying to open a channel to talk to our
* agent. Give them back a local channel number. */
struct ssh_channel *c;
/* Refuse if agent forwarding is disabled. */
if (!ssh_agentfwd_enabled) {
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body), PKT_END);
} else {
c = smalloc(sizeof(struct ssh_channel));
c->remoteid = GET_32BIT(pktin.body);
c->localid = alloc_channel_id();
c->closes = 0;
c->v.v1.throttling = 0;
c->type = CHAN_AGENT; /* identify channel type */
c->u.a.lensofar = 0;
add234(ssh_channels, c);
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT, c->localid,
PKT_END);
}
} else if (pktin.type == SSH1_MSG_PORT_OPEN) {
/* Remote side is trying to open a channel to talk to a
* forwarded port. Give them back a local channel number. */
struct ssh_channel *c;
struct ssh_rportfwd pf;
int hostsize, port;
char host[256], buf[1024];
char *p, *h, *e;
c = smalloc(sizeof(struct ssh_channel));
hostsize = GET_32BIT(pktin.body+4);
for(h = host, p = pktin.body+8; hostsize != 0; hostsize--) {
if (h+1 < host+sizeof(host))
*h++ = *p;
p++;
}
*h = 0;
port = GET_32BIT(p);
strcpy(pf.dhost, host);
pf.dport = port;
if (find234(ssh_rportfwds, &pf, NULL) == NULL) {
sprintf(buf, "Rejected remote port open request for %s:%d",
host, port);
logevent(buf);
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body), PKT_END);
} else {
sprintf(buf, "Received remote port open request for %s:%d",
host, port);
logevent(buf);
e = pfd_newconnect(&c->u.pfd.s, host, port, c);
if (e != NULL) {
char buf[256];
sprintf(buf, "Port open failed: %s", e);
logevent(buf);
sfree(c);
send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
PKT_INT, GET_32BIT(pktin.body),
PKT_END);
} else {
c->remoteid = GET_32BIT(pktin.body);
c->localid = alloc_channel_id();
c->closes = 0;
c->v.v1.throttling = 0;
c->type = CHAN_SOCKDATA; /* identify channel type */
add234(ssh_channels, c);
send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
PKT_INT, c->remoteid, PKT_INT,
c->localid, PKT_END);
logevent("Forwarded port opened successfully");
}
}
} else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
unsigned int remoteid = GET_32BIT(pktin.body);
unsigned int localid = GET_32BIT(pktin.body+4);
struct ssh_channel *c;
c = find234(ssh_channels, &remoteid, ssh_channelfind);
if (c && c->type == CHAN_SOCKDATA_DORMANT) {
c->remoteid = localid;
c->type = CHAN_SOCKDATA;
pfd_confirm(c->u.pfd.s);
}
} else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
unsigned int remoteid = GET_32BIT(pktin.body);
unsigned int localid = GET_32BIT(pktin.body+4);
struct ssh_channel *c;
c = find234(ssh_channels, &remoteid, ssh_channelfind);
if (c && c->type == CHAN_SOCKDATA_DORMANT) {
logevent("Forwarded connection refused by server");
pfd_close(c->u.pfd.s);
del234(ssh_channels, c);
sfree(c);
}
} else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
/* Remote side closes a channel. */
unsigned i = GET_32BIT(pktin.body);
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (c) {
int closetype;
closetype =
(pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
if (!(c->closes & closetype))
send_packet(pktin.type, PKT_INT, c->remoteid,
PKT_END);
if ((c->closes == 0) && (c->type == CHAN_X11)) {
logevent("Forwarded X11 connection terminated");
assert(c->u.x11.s != NULL);
x11_close(c->u.x11.s);
c->u.x11.s = NULL;
}
if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
logevent("Forwarded port closed");
assert(c->u.pfd.s != NULL);
pfd_close(c->u.pfd.s);
c->u.pfd.s = NULL;
}
c->closes |= closetype;
if (c->closes == 3) {
del234(ssh_channels, c);
sfree(c);
}
}
} else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
/* Data sent down one of our channels. */
int i = GET_32BIT(pktin.body);
int len = GET_32BIT(pktin.body + 4);
unsigned char *p = pktin.body + 8;
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (c) {
int bufsize;
switch (c->type) {
case CHAN_X11:
bufsize = x11_send(c->u.x11.s, p, len);
break;
case CHAN_SOCKDATA:
bufsize = pfd_send(c->u.pfd.s, p, len);
break;
case CHAN_AGENT:
/* Data for an agent message. Buffer it. */
while (len > 0) {
if (c->u.a.lensofar < 4) {
int l = min(4 - c->u.a.lensofar, len);
memcpy(c->u.a.msglen + c->u.a.lensofar, p,
l);
p += l;
len -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == 4) {
c->u.a.totallen =
4 + GET_32BIT(c->u.a.msglen);
c->u.a.message = smalloc(c->u.a.totallen);
memcpy(c->u.a.message, c->u.a.msglen, 4);
}
if (c->u.a.lensofar >= 4 && len > 0) {
int l =
min(c->u.a.totallen - c->u.a.lensofar,
len);
memcpy(c->u.a.message + c->u.a.lensofar, p,
l);
p += l;
len -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == c->u.a.totallen) {
void *reply, *sentreply;
int replylen;
agent_query(c->u.a.message,
c->u.a.totallen, &reply,
&replylen);
if (reply)
sentreply = reply;
else {
/* Fake SSH_AGENT_FAILURE. */
sentreply = "\0\0\0\1\5";
replylen = 5;
}
send_packet(SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKT_INT, replylen,
PKT_DATA, sentreply, replylen,
PKT_END);
if (reply)
sfree(reply);
sfree(c->u.a.message);
c->u.a.lensofar = 0;
}
}
bufsize = 0; /* agent channels never back up */
break;
}
if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
c->v.v1.throttling = 1;
ssh1_throttle(+1);
}
}
} else if (pktin.type == SSH1_SMSG_SUCCESS) {
/* may be from EXEC_SHELL on some servers */
} else if (pktin.type == SSH1_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 == 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;
}
} else {
while (inlen > 0) {
int len = min(inlen, 512);
send_packet(SSH1_CMSG_STDIN_DATA,
PKT_INT, len, PKT_DATA, in, len, PKT_END);
in += len;
inlen -= len;
}
}
}
crFinishV;
}
/*
* Utility routine for decoding comma-separated strings in KEXINIT.
*/
static int in_commasep_string(char *needle, char *haystack, int haylen)
{
int needlen = strlen(needle);
while (1) {
/*
* Is it at the start of the string?
*/
if (haylen >= needlen && /* haystack is long enough */
!memcmp(needle, haystack, needlen) && /* initial match */
(haylen == needlen || haystack[needlen] == ',')
/* either , or EOS follows */
)
return 1;
/*
* If not, search for the next comma and resume after that.
* If no comma found, terminate.
*/
while (haylen > 0 && *haystack != ',')
haylen--, haystack++;
if (haylen == 0)
return 0;
haylen--, haystack++; /* skip over comma itself */
}
}
/*
* SSH2 key creation method.
*/
static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr,
char *keyspace)
{
SHA_State s;
/* First 20 bytes. */
SHA_Init(&s);
sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, &chr, 1);
SHA_Bytes(&s, sessid, 20);
SHA_Final(&s, keyspace);
/* Next 20 bytes. */
SHA_Init(&s);
sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, keyspace, 20);
SHA_Final(&s, keyspace + 20);
}
/*
* Handle the SSH2 transport layer.
*/
static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
{
static int i, j, len, nbits, pbits, warn;
static char *str;
static Bignum p, g, e, f, K;
static int kex_init_value, kex_reply_value;
static const struct ssh_mac **maclist;
static int nmacs;
static const struct ssh2_cipher *cscipher_tobe = NULL;
static const struct ssh2_cipher *sccipher_tobe = NULL;
static const struct ssh_mac *csmac_tobe = NULL;
static const struct ssh_mac *scmac_tobe = NULL;
static const struct ssh_compress *cscomp_tobe = NULL;
static const struct ssh_compress *sccomp_tobe = NULL;
static char *hostkeydata, *sigdata, *keystr, *fingerprint;
static int hostkeylen, siglen;
static void *hkey; /* actual host key */
static unsigned char exchange_hash[20];
static unsigned char keyspace[40];
static int n_preferred_ciphers;
static const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
static const struct ssh_compress *preferred_comp;
static int first_kex;
crBegin;
random_init();
first_kex = 1;
/*
* Set up the preferred ciphers. (NULL => warn below here)
*/
n_preferred_ciphers = 0;
for (i = 0; i < CIPHER_MAX; i++) {
switch (cfg.ssh_cipherlist[i]) {
case CIPHER_BLOWFISH:
preferred_ciphers[n_preferred_ciphers] = &ssh2_blowfish;
n_preferred_ciphers++;
break;
case CIPHER_DES:
/* Not supported in SSH2; silently drop */
break;
case CIPHER_3DES:
preferred_ciphers[n_preferred_ciphers] = &ssh2_3des;
n_preferred_ciphers++;
break;
case CIPHER_AES:
preferred_ciphers[n_preferred_ciphers] = &ssh2_aes;
n_preferred_ciphers++;
break;
case CIPHER_WARN:
/* Flag for later. Don't bother if it's the last in
* the list. */
if (i < CIPHER_MAX - 1) {
preferred_ciphers[n_preferred_ciphers] = NULL;
n_preferred_ciphers++;
}
break;
}
}
/*
* Set up preferred compression.
*/
if (cfg.compression)
preferred_comp = &ssh_zlib;
else
preferred_comp = &ssh_comp_none;
/*
* Be prepared to work around the buggy MAC problem.
*/
if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
maclist = buggymacs, nmacs = lenof(buggymacs);
else
maclist = macs, nmacs = lenof(macs);
begin_key_exchange:
/*
* Construct and send our key exchange packet.
*/
ssh2_pkt_init(SSH2_MSG_KEXINIT);
for (i = 0; i < 16; i++)
ssh2_pkt_addbyte((unsigned char) random_byte());
/* List key exchange algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(kex_algs); i++) {
ssh2_pkt_addstring_str(kex_algs[i]->name);
if (i < lenof(kex_algs) - 1)
ssh2_pkt_addstring_str(",");
}
/* List server host key algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(hostkey_algs); i++) {
ssh2_pkt_addstring_str(hostkey_algs[i]->name);
if (i < lenof(hostkey_algs) - 1)
ssh2_pkt_addstring_str(",");
}
/* List client->server encryption algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = preferred_ciphers[i];
if (!c) continue; /* warning flag */
for (j = 0; j < c->nciphers; j++) {
ssh2_pkt_addstring_str(c->list[j]->name);
if (i < n_preferred_ciphers || j < c->nciphers - 1)
ssh2_pkt_addstring_str(",");
}
}
/* List server->client encryption algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = preferred_ciphers[i];
if (!c) continue; /* warning flag */
for (j = 0; j < c->nciphers; j++) {
ssh2_pkt_addstring_str(c->list[j]->name);
if (i < n_preferred_ciphers || j < c->nciphers - 1)
ssh2_pkt_addstring_str(",");
}
}
/* List client->server MAC algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < nmacs; i++) {
ssh2_pkt_addstring_str(maclist[i]->name);
if (i < nmacs - 1)
ssh2_pkt_addstring_str(",");
}
/* List server->client MAC algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < nmacs; i++) {
ssh2_pkt_addstring_str(maclist[i]->name);
if (i < nmacs - 1)
ssh2_pkt_addstring_str(",");
}
/* List client->server compression algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(compressions) + 1; i++) {
const struct ssh_compress *c =
i == 0 ? preferred_comp : compressions[i - 1];
ssh2_pkt_addstring_str(c->name);
if (i < lenof(compressions))
ssh2_pkt_addstring_str(",");
}
/* List server->client compression algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(compressions) + 1; i++) {
const struct ssh_compress *c =
i == 0 ? preferred_comp : compressions[i - 1];
ssh2_pkt_addstring_str(c->name);
if (i < lenof(compressions))
ssh2_pkt_addstring_str(",");
}
/* List client->server languages. Empty list. */
ssh2_pkt_addstring_start();
/* List server->client languages. Empty list. */
ssh2_pkt_addstring_start();
/* First KEX packet does _not_ follow, because we're not that brave. */
ssh2_pkt_addbool(FALSE);
/* Reserved. */
ssh2_pkt_adduint32(0);
exhash = exhashbase;
sha_string(&exhash, pktout.data + 5, pktout.length - 5);
ssh2_pkt_send();
if (!ispkt)
crWaitUntil(ispkt);
sha_string(&exhash, pktin.data + 5, pktin.length - 5);
/*
* Now examine the other side's KEXINIT to see what we're up
* to.
*/
if (pktin.type != SSH2_MSG_KEXINIT) {
bombout(("expected key exchange packet from server"));
crReturn(0);
}
kex = NULL;
hostkey = NULL;
cscipher_tobe = NULL;
sccipher_tobe = NULL;
csmac_tobe = NULL;
scmac_tobe = NULL;
cscomp_tobe = NULL;
sccomp_tobe = NULL;
pktin.savedpos += 16; /* skip garbage cookie */
ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
for (i = 0; i < lenof(kex_algs); i++) {
if (in_commasep_string(kex_algs[i]->name, str, len)) {
kex = kex_algs[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* host key algorithms */
for (i = 0; i < lenof(hostkey_algs); i++) {
if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
hostkey = hostkey_algs[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* client->server cipher */
warn = 0;
for (i = 0; i < n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = preferred_ciphers[i];
if (!c) {
warn = 1;
} else {
for (j = 0; j < c->nciphers; j++) {
if (in_commasep_string(c->list[j]->name, str, len)) {
cscipher_tobe = c->list[j];
break;
}
}
}
if (cscipher_tobe) {
if (warn)
askcipher(cscipher_tobe->name, 1);
break;
}
}
ssh2_pkt_getstring(&str, &len); /* server->client cipher */
warn = 0;
for (i = 0; i < n_preferred_ciphers; i++) {
const struct ssh2_ciphers *c = preferred_ciphers[i];
if (!c) {
warn = 1;
} else {
for (j = 0; j < c->nciphers; j++) {
if (in_commasep_string(c->list[j]->name, str, len)) {
sccipher_tobe = c->list[j];
break;
}
}
}
if (sccipher_tobe) {
if (warn)
askcipher(sccipher_tobe->name, 2);
break;
}
}
ssh2_pkt_getstring(&str, &len); /* client->server mac */
for (i = 0; i < nmacs; i++) {
if (in_commasep_string(maclist[i]->name, str, len)) {
csmac_tobe = maclist[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* server->client mac */
for (i = 0; i < nmacs; i++) {
if (in_commasep_string(maclist[i]->name, str, len)) {
scmac_tobe = maclist[i];
break;
}
}
ssh2_pkt_getstring(&str, &len); /* client->server compression */
for (i = 0; i < lenof(compressions) + 1; i++) {
const struct ssh_compress *c =
i == 0 ? preferred_comp : compressions[i - 1];
if (in_commasep_string(c->name, str, len)) {
cscomp_tobe = c;
break;
}
}
ssh2_pkt_getstring(&str, &len); /* server->client compression */
for (i = 0; i < lenof(compressions) + 1; i++) {
const struct ssh_compress *c =
i == 0 ? preferred_comp : compressions[i - 1];
if (in_commasep_string(c->name, str, len)) {
sccomp_tobe = c;
break;
}
}
/*
* 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) {
logevent("Doing Diffie-Hellman group exchange");
/*
* 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(pbits);
ssh2_pkt_send();
crWaitUntil(ispkt);
if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
bombout(("expected key exchange group packet from server"));
crReturn(0);
}
p = ssh2_pkt_getmp();
g = ssh2_pkt_getmp();
dh_setup_group(p, g);
kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
} else {
dh_setup_group1();
kex_init_value = SSH2_MSG_KEXDH_INIT;
kex_reply_value = SSH2_MSG_KEXDH_REPLY;
}
logevent("Doing Diffie-Hellman key exchange");
/*
* Now generate and send e for Diffie-Hellman.
*/
e = dh_create_e(nbits * 2);
ssh2_pkt_init(kex_init_value);
ssh2_pkt_addmp(e);
ssh2_pkt_send();
crWaitUntil(ispkt);
if (pktin.type != kex_reply_value) {
bombout(("expected key exchange reply packet from server"));
crReturn(0);
}
ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
f = ssh2_pkt_getmp();
ssh2_pkt_getstring(&sigdata, &siglen);
K = dh_find_K(f);
sha_string(&exhash, hostkeydata, hostkeylen);
if (kex == &ssh_diffiehellman_gex) {
sha_uint32(&exhash, pbits);
sha_mpint(&exhash, p);
sha_mpint(&exhash, g);
}
sha_mpint(&exhash, e);
sha_mpint(&exhash, f);
sha_mpint(&exhash, K);
SHA_Final(&exhash, exchange_hash);
dh_cleanup();
#if 0
debug(("Exchange hash is:\n"));
dmemdump(exchange_hash, 20);
#endif
hkey = hostkey->newkey(hostkeydata, hostkeylen);
if (!hkey ||
!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
bombout(("Server's host key did not match the signature supplied"));
crReturn(0);
}
/*
* Expect SSH2_MSG_NEWKEYS from server.
*/
crWaitUntil(ispkt);
if (pktin.type != SSH2_MSG_NEWKEYS) {
bombout(("expected new-keys packet from server"));
crReturn(0);
}
/*
* Authenticate remote host: verify host key. (We've already
* checked the signature of the exchange hash.)
*/
keystr = hostkey->fmtkey(hkey);
fingerprint = hostkey->fingerprint(hkey);
verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
keystr, fingerprint);
if (first_kex) { /* don't bother logging this in rekeys */
logevent("Host key fingerprint is:");
logevent(fingerprint);
}
sfree(fingerprint);
sfree(keystr);
hostkey->freekey(hkey);
/*
* Send SSH2_MSG_NEWKEYS.
*/
ssh2_pkt_init(SSH2_MSG_NEWKEYS);
ssh2_pkt_send();
/*
* Create and initialise session keys.
*/
cscipher = cscipher_tobe;
sccipher = sccipher_tobe;
csmac = csmac_tobe;
scmac = scmac_tobe;
cscomp = cscomp_tobe;
sccomp = sccomp_tobe;
cscomp->compress_init();
sccomp->decompress_init();
/*
* Set IVs after keys. Here we use the exchange hash from the
* _first_ key exchange.
*/
if (first_kex)
memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
cscipher->setcskey(keyspace);
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
sccipher->setsckey(keyspace);
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
cscipher->setcsiv(keyspace);
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
sccipher->setsciv(keyspace);
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
csmac->setcskey(keyspace);
ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
scmac->setsckey(keyspace);
/*
* If this is the first key exchange phase, we must pass the
* SSH2_MSG_NEWKEYS packet to the next layer, not because it
* wants to see it but because it will need time to initialise
* itself before it sees an actual packet. In subsequent key
* exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
* it would only confuse the layer above.
*/
if (!first_kex) {
crReturn(0);
}
first_kex = 0;
/*
* Now we're encrypting. Begin returning 1 to the protocol main
* function so that other things can run on top of the
* transport. If we ever see a KEXINIT, we must go back to the
* start.
*/
while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
crReturn(1);
}
logevent("Server initiated key re-exchange");
goto begin_key_exchange;
crFinish(1);
}
/*
* Add data to an SSH2 channel output buffer.
*/
static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
int len)
{
bufchain_add(&c->v.v2.outbuffer, buf, len);
}
/*
* Attempt to send data on an SSH2 channel.
*/
static int ssh2_try_send(struct ssh_channel *c)
{
while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
int len;
void *data;
bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
if ((unsigned)len > c->v.v2.remwindow)
len = c->v.v2.remwindow;
if ((unsigned)len > c->v.v2.remmaxpkt)
len = c->v.v2.remmaxpkt;
ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(data, len);
ssh2_pkt_send();
bufchain_consume(&c->v.v2.outbuffer, len);
c->v.v2.remwindow -= len;
}
/*
* After having sent as much data as we can, return the amount
* still buffered.
*/
return bufchain_size(&c->v.v2.outbuffer);
}
/*
* Potentially enlarge the window on an SSH2 channel.
*/
static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
{
if (newwin > c->v.v2.locwindow) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_adduint32(newwin - c->v.v2.locwindow);
ssh2_pkt_send();
c->v.v2.locwindow = newwin;
}
}
/*
* Handle the SSH2 userauth and connection layers.
*/
static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
{
static enum {
AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
AUTH_PASSWORD,
AUTH_KEYBOARD_INTERACTIVE
} method;
static enum {
AUTH_TYPE_NONE,
AUTH_TYPE_PUBLICKEY,
AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
AUTH_TYPE_PASSWORD,
AUTH_TYPE_KEYBOARD_INTERACTIVE,
AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
} type;
static int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
static int tried_pubkey_config, tried_agent, tried_keyb_inter;
static int kbd_inter_running;
static int we_are_in;
static int num_prompts, echo;
static char username[100];
static char pwprompt[200];
static char password[100];
crBegin;
/*
* Request userauth protocol, and await a response to it.
*/
ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
ssh2_pkt_addstring("ssh-userauth");
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
bombout(("Server refused user authentication protocol"));
crReturnV;
}
/*
* We repeat this whole loop, including the username prompt,
* until we manage a successful authentication. If the user
* types the wrong _password_, they are sent back to the
* beginning to try another username. (If they specify a
* username in the config, they are never asked, even if they
* do give a wrong password.)
*
* I think this best serves the needs of
*
* - the people who have no configuration, no keys, and just
* want to try repeated (username,password) pairs until they
* type both correctly
*
* - people who have keys and configuration but occasionally
* need to fall back to passwords
*
* - people with a key held in Pageant, who might not have
* logged in to a particular machine before; so they want to
* type a username, and then _either_ their key will be
* accepted, _or_ they will type a password. If they mistype
* the username they will want to be able to get back and
* retype it!
*/
do {
static int pos;
static char c;
/*
* Get a username.
*/
pos = 0;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
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 < sizeof(username)-1) {
username[pos++] = c;
c_write(&c, 1);
}
break;
}
}
}
c_write_str("\r\n");
username[strcspn(username, "\n\r")] = '\0';
} else {
char stuff[200];
strncpy(username, cfg.username, 99);
username[99] = '\0';
if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
sprintf(stuff, "Using username \"%s\".\r\n", username);
c_write_str(stuff);
}
}
/*
* Send an authentication request using method "none": (a)
* just in case it succeeds, and (b) so that we know what
* authentication methods we can usefully try next.
*/
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("none"); /* method */
ssh2_pkt_send();
type = AUTH_TYPE_NONE;
gotit = FALSE;
we_are_in = FALSE;
tried_pubkey_config = FALSE;
tried_agent = FALSE;
tried_keyb_inter = FALSE;
kbd_inter_running = FALSE;
while (1) {
/*
* Wait for the result of the last authentication request.
*/
if (!gotit)
crWaitUntilV(ispkt);
while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
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) {
logevent("Access granted");
we_are_in = TRUE;
break;
}
if (kbd_inter_running &&
pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
/*
* This is a further prompt in keyboard-interactive
* authentication. Do nothing.
*/
} else if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
bombout(("Strange packet received during authentication: type %d",
pktin.type));
crReturnV;
}
gotit = FALSE;
/*
* OK, we're now sitting on a USERAUTH_FAILURE message, so
* we can look at the string in it and know what we can
* helpfully try next.
*/
if (pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
char *methods;
int methlen;
ssh2_pkt_getstring(&methods, &methlen);
kbd_inter_running = FALSE;
if (!ssh2_pkt_getbool()) {
/*
* We have received an unequivocal Access
* Denied. This can translate to a variety of
* messages:
*
* - if we'd just tried "none" authentication,
* it's not worth printing anything at all
*
* - if we'd just tried a public key _offer_,
* the message should be "Server refused our
* key" (or no message at all if the key
* came from Pageant)
*
* - if we'd just tried anything else, the
* message really should be "Access denied".
*
* Additionally, if we'd just tried password
* authentication, we should break out of this
* whole loop so as to go back to the username
* prompt.
*/
if (type == AUTH_TYPE_NONE) {
/* do nothing */
} else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
c_write_str("Server refused our key\r\n");
logevent("Server refused public key");
} else if (type == AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
/* server declined keyboard-interactive; ignore */
} else {
c_write_str("Access denied\r\n");
logevent("Access denied");
if (type == AUTH_TYPE_PASSWORD) {
we_are_in = FALSE;
break;
}
}
} else {
c_write_str("Further authentication required\r\n");
logevent("Further authentication required");
}
can_pubkey =
in_commasep_string("publickey", methods, methlen);
can_passwd =
in_commasep_string("password", methods, methlen);
can_keyb_inter =
in_commasep_string("keyboard-interactive", methods, methlen);
}
method = 0;
if (!method && can_pubkey && agent_exists() && !tried_agent) {
/*
* Attempt public-key authentication using Pageant.
*/
static unsigned char request[5], *response, *p;
static int responselen;
static int i, nkeys;
static int authed = FALSE;
void *r;
tried_agent = TRUE;
logevent("Pageant is running. Requesting keys.");
/* Request the keys held by the agent. */
PUT_32BIT(request, 1);
request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
agent_query(request, 5, &r, &responselen);
response = (unsigned char *) r;
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 SSH2 keys", nkeys);
logevent(buf);
}
for (i = 0; i < nkeys; i++) {
static char *pkblob, *alg, *commentp;
static int pklen, alglen, commentlen;
static int siglen, retlen, len;
static char *q, *agentreq, *ret;
void *vret;
{
char buf[64];
sprintf(buf, "Trying Pageant key #%d", i);
logevent(buf);
}
pklen = GET_32BIT(p);
p += 4;
pkblob = p;
p += pklen;
alglen = GET_32BIT(pkblob);
alg = pkblob + 4;
commentlen = GET_32BIT(p);
p += 4;
commentp = p;
p += commentlen;
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("publickey"); /* method */
ssh2_pkt_addbool(FALSE); /* no signature included */
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(alg, alglen);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(pkblob, pklen);
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
logevent("Key refused");
continue;
}
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.
* Construct a SIGN_REQUEST.
*/
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("publickey"); /* method */
ssh2_pkt_addbool(TRUE);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(alg, alglen);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(pkblob, pklen);
siglen = pktout.length - 5 + 4 + 20;
len = 1; /* message type */
len += 4 + pklen; /* key blob */
len += 4 + siglen; /* data to sign */
len += 4; /* flags */
agentreq = smalloc(4 + len);
PUT_32BIT(agentreq, len);
q = agentreq + 4;
*q++ = SSH2_AGENTC_SIGN_REQUEST;
PUT_32BIT(q, pklen);
q += 4;
memcpy(q, pkblob, pklen);
q += pklen;
PUT_32BIT(q, siglen);
q += 4;
/* Now the data to be signed... */
PUT_32BIT(q, 20);
q += 4;
memcpy(q, ssh2_session_id, 20);
q += 20;
memcpy(q, pktout.data + 5, pktout.length - 5);
q += pktout.length - 5;
/* And finally the (zero) flags word. */
PUT_32BIT(q, 0);
agent_query(agentreq, len + 4, &vret, &retlen);
ret = vret;
sfree(agentreq);
if (ret) {
if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
logevent("Sending Pageant's response");
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(ret + 9,
GET_32BIT(ret +
5));
ssh2_pkt_send();
authed = TRUE;
break;
} else {
logevent
("Pageant failed to answer challenge");
sfree(ret);
}
}
}
if (authed)
continue;
}
}
if (!method && can_pubkey && *cfg.keyfile
&& !tried_pubkey_config) {
unsigned char *pub_blob;
char *algorithm, *comment;
int pub_blob_len;
tried_pubkey_config = TRUE;
/*
* Try the public key supplied in the configuration.
*
* First, offer the public blob to see if the server is
* willing to accept it.
*/
pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
&pub_blob_len);
if (pub_blob) {
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("publickey"); /* method */
ssh2_pkt_addbool(FALSE); /* no signature included */
ssh2_pkt_addstring(algorithm);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
ssh2_pkt_send();
logevent("Offered public key"); /* FIXME */
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
gotit = TRUE;
type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
continue; /* key refused; give up on it */
}
logevent("Offer of public key accepted");
/*
* Actually attempt a serious authentication using
* the key.
*/
if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
sprintf(pwprompt,
"Passphrase for key \"%.100s\": ",
comment);
need_pw = TRUE;
} else {
need_pw = FALSE;
}
c_write_str("Authenticating with public key \"");
c_write_str(comment);
c_write_str("\"\r\n");
method = AUTH_PUBLICKEY_FILE;
}
}
if (!method && can_keyb_inter && !tried_keyb_inter) {
method = AUTH_KEYBOARD_INTERACTIVE;
type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
tried_keyb_inter = TRUE;
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("keyboard-interactive"); /* method */
ssh2_pkt_addstring(""); /* lang */
ssh2_pkt_addstring("");
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
if (pktin.type == SSH2_MSG_USERAUTH_FAILURE)
gotit = TRUE;
logevent("Keyboard-interactive authentication refused");
type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
continue;
}
kbd_inter_running = TRUE;
}
if (kbd_inter_running) {
method = AUTH_KEYBOARD_INTERACTIVE;
type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
tried_keyb_inter = TRUE;
/* We've got packet with that "interactive" info
dump banners, and set its prompt as ours */
{
char *name, *inst, *lang, *prompt;
int name_len, inst_len, lang_len, prompt_len;
ssh2_pkt_getstring(&name, &name_len);
ssh2_pkt_getstring(&inst, &inst_len);
ssh2_pkt_getstring(&lang, &lang_len);
if (name_len > 0)
c_write_untrusted(name, name_len);
if (inst_len > 0)
c_write_untrusted(inst, inst_len);
num_prompts = ssh2_pkt_getuint32();
ssh2_pkt_getstring(&prompt, &prompt_len);
strncpy(pwprompt, prompt, sizeof(pwprompt));
need_pw = TRUE;
echo = ssh2_pkt_getbool();
}
}
if (!method && can_passwd) {
method = AUTH_PASSWORD;
sprintf(pwprompt, "%.90s@%.90s's password: ", username,
savedhost);
need_pw = TRUE;
}
if (need_pw) {
if (ssh_get_line) {
if (!ssh_get_line(pwprompt, password,
sizeof(password), TRUE)) {
/*
* get_line failed to get a password (for
* example because one was supplied on the
* command line which has already failed to
* work). Terminate.
*/
ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring
("No more passwords available to try");
ssh2_pkt_addstring("en"); /* language tag */
ssh2_pkt_send();
connection_fatal("Unable to authenticate");
ssh_state = SSH_STATE_CLOSED;
crReturnV;
}
} else {
static int pos = 0;
static char c;
c_write_untrusted(pwprompt, strlen(pwprompt));
ssh_send_ok = 1;
pos = 0;
while (pos >= 0) {
crWaitUntilV(!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 (pos < sizeof(password)-1)
password[pos++] = c;
break;
}
}
c_write_str("\r\n");
}
}
if (method == AUTH_PUBLICKEY_FILE) {
/*
* We have our passphrase. Now try the actual authentication.
*/
struct ssh2_userkey *key;
key = ssh2_load_userkey(cfg.keyfile, password);
if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
if (key == SSH2_WRONG_PASSPHRASE) {
c_write_str("Wrong passphrase\r\n");
tried_pubkey_config = FALSE;
} else {
c_write_str("Unable to load private key\r\n");
tried_pubkey_config = TRUE;
}
/* Send a spurious AUTH_NONE to return to the top. */
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("none"); /* method */
ssh2_pkt_send();
type = AUTH_TYPE_NONE;
} else {
unsigned char *blob, *sigdata;
int blob_len, sigdata_len;
/*
* We have loaded the private key and the server
* has announced that it's willing to accept it.
* Hallelujah. Generate a signature and send it.
*/
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("publickey"); /* method */
ssh2_pkt_addbool(TRUE);
ssh2_pkt_addstring(key->alg->name);
blob = key->alg->public_blob(key->data, &blob_len);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(blob, blob_len);
sfree(blob);
/*
* The data to be signed is:
*
* string session-id
*
* followed by everything so far placed in the
* outgoing packet.
*/
sigdata_len = pktout.length - 5 + 4 + 20;
sigdata = smalloc(sigdata_len);
PUT_32BIT(sigdata, 20);
memcpy(sigdata + 4, ssh2_session_id, 20);
memcpy(sigdata + 24, pktout.data + 5,
pktout.length - 5);
blob =
key->alg->sign(key->data, sigdata, sigdata_len,
&blob_len);
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data(blob, blob_len);
sfree(blob);
sfree(sigdata);
ssh2_pkt_send();
type = AUTH_TYPE_PUBLICKEY;
}
} else if (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.
*
* 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
* people who find out how long their password is!
*/
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
ssh2_pkt_addstring(username);
ssh2_pkt_addstring("ssh-connection"); /* service requested */
ssh2_pkt_addstring("password");
ssh2_pkt_addbool(FALSE);
ssh2_pkt_addstring(password);
ssh2_pkt_defer();
/*
* 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 (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 = 0; i < stringlen; i++) {
char c = (char) random_byte();
ssh2_pkt_addstring_data(&c, 1);
}
ssh2_pkt_defer();
}
ssh_pkt_defersend();
logevent("Sent password");
type = AUTH_TYPE_PASSWORD;
} else if (method == AUTH_KEYBOARD_INTERACTIVE) {
ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
ssh2_pkt_adduint32(num_prompts);
ssh2_pkt_addstring(password);
memset(password, 0, sizeof(password));
ssh2_pkt_send();
type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
} else {
c_write_str
("No supported authentication methods left to try!\r\n");
logevent
("No supported authentications offered. Disconnecting");
ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring
("No supported authentication methods available");
ssh2_pkt_addstring("en"); /* language tag */
ssh2_pkt_send();
ssh_state = SSH_STATE_CLOSED;
crReturnV;
}
}
} while (!we_are_in);
/*
* Now we're authenticated for the connection protocol. The
* connection protocol will automatically have started at this
* point; there's no need to send SERVICE_REQUEST.
*/
/*
* So now create a channel with a session in it.
*/
ssh_channels = newtree234(ssh_channelcmp);
mainchan = smalloc(sizeof(struct ssh_channel));
mainchan->localid = alloc_channel_id();
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
ssh2_pkt_addstring("session");
ssh2_pkt_adduint32(mainchan->localid);
mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
ssh2_pkt_adduint32(mainchan->v.v2.locwindow); /* our window size */
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
ssh2_pkt_send();
crWaitUntilV(ispkt);
if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
bombout(("Server refused to open a session"));
crReturnV;
/* FIXME: error data comes back in FAILURE packet */
}
if (ssh2_pkt_getuint32() != mainchan->localid) {
bombout(("Server's channel confirmation cited wrong channel"));
crReturnV;
}
mainchan->remoteid = ssh2_pkt_getuint32();
mainchan->type = CHAN_MAINSESSION;
mainchan->closes = 0;
mainchan->v.v2.remwindow = ssh2_pkt_getuint32();
mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32();
bufchain_init(&mainchan->v.v2.outbuffer);
add234(ssh_channels, mainchan);
logevent("Opened channel for session");
/*
* Potentially enable X11 forwarding.
*/
if (cfg.x11_forward) {
char proto[20], data[64];
logevent("Requesting X11 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("x11-req");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addbool(0); /* many connections */
ssh2_pkt_addstring(proto);
ssh2_pkt_addstring(data);
ssh2_pkt_adduint32(0); /* screen number */
ssh2_pkt_send();
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v.v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to X11 forwarding request:"
" packet type %d", pktin.type));
crReturnV;
}
logevent("X11 forwarding refused");
} else {
logevent("X11 forwarding enabled");
ssh_X11_fwd_enabled = TRUE;
}
}
/*
* Enable port forwardings.
*/
{
static char *e; /* preserve across crReturn */
char type;
int n;
int sport,dport;
char sports[256], dports[256], host[256];
char buf[1024];
ssh_rportfwds = newtree234(ssh_rportcmp_ssh2);
/* Add port forwardings. */
e = cfg.portfwd;
while (*e) {
type = *e++;
n = 0;
while (*e && *e != '\t')
sports[n++] = *e++;
sports[n] = 0;
if (*e == '\t')
e++;
n = 0;
while (*e && *e != ':')
host[n++] = *e++;
host[n] = 0;
if (*e == ':')
e++;
n = 0;
while (*e)
dports[n++] = *e++;
dports[n] = 0;
e++;
dport = atoi(dports);
sport = atoi(sports);
if (sport && dport) {
if (type == 'L') {
pfd_addforward(host, dport, sport);
sprintf(buf, "Local port %d forwarding to %s:%d",
sport, host, dport);
logevent(buf);
} else {
struct ssh_rportfwd *pf;
pf = smalloc(sizeof(*pf));
strcpy(pf->dhost, host);
pf->dport = dport;
pf->sport = sport;
if (add234(ssh_rportfwds, pf) != pf) {
sprintf(buf,
"Duplicate remote port forwarding to %s:%d",
host, dport);
logevent(buf);
sfree(pf);
} else {
sprintf(buf, "Requesting remote port %d (forwarded to %s:%d)",
sport, host, dport);
logevent(buf);
ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
ssh2_pkt_addstring("tcpip-forward");
ssh2_pkt_addbool(1);/* want reply */
ssh2_pkt_addstring("127.0.0.1");
ssh2_pkt_adduint32(sport);
ssh2_pkt_send();
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue;/* nonexistent channel */
c->v.v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
if (pktin.type != SSH2_MSG_REQUEST_FAILURE) {
bombout(("Unexpected response to port "
"forwarding request: packet type %d",
pktin.type));
crReturnV;
}
logevent("Server refused this port forwarding");
} else {
logevent("Remote port forwarding enabled");
}
}
}
}
}
}
/*
* Potentially enable agent forwarding.
*/
if (cfg.agentfwd && agent_exists()) {
logevent("Requesting OpenSSH-style agent forwarding");
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_addstring("auth-agent-req@openssh.com");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_send();
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v.v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to agent forwarding request:"
" packet type %d", pktin.type));
crReturnV;
}
logevent("Agent forwarding refused");
} else {
logevent("Agent forwarding enabled");
ssh_agentfwd_enabled = TRUE;
}
}
/*
* Now allocate a pty for the session.
*/
if (!cfg.nopty) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
ssh2_pkt_addstring("pty-req");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addstring(cfg.termtype);
ssh2_pkt_adduint32(cols);
ssh2_pkt_adduint32(rows);
ssh2_pkt_adduint32(0); /* pixel width */
ssh2_pkt_adduint32(0); /* pixel height */
ssh2_pkt_addstring_start();
ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
ssh2_pkt_send();
ssh_state = SSH_STATE_INTERMED;
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v.v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to pty request:"
" packet type %d", pktin.type));
crReturnV;
}
c_write_str("Server refused to allocate pty\r\n");
ssh_editing = ssh_echoing = 1;
} else {
logevent("Allocated pty");
}
} else {
ssh_editing = ssh_echoing = 1;
}
/*
* Start a shell or a remote command. We may have to attempt
* this twice if the config data has provided a second choice
* of command.
*/
while (1) {
int subsys;
char *cmd;
if (ssh_fallback_cmd) {
subsys = cfg.ssh_subsys2;
cmd = cfg.remote_cmd_ptr2;
} else {
subsys = cfg.ssh_subsys;
cmd = cfg.remote_cmd_ptr;
}
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
if (subsys) {
ssh2_pkt_addstring("subsystem");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addstring(cmd);
} else if (*cmd) {
ssh2_pkt_addstring("exec");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addstring(cmd);
} else {
ssh2_pkt_addstring("shell");
ssh2_pkt_addbool(1); /* want reply */
}
ssh2_pkt_send();
do {
crWaitUntilV(ispkt);
if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v.v2.remwindow += ssh2_pkt_getuint32();
}
} while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
bombout(("Unexpected response to shell/command request:"
" packet type %d", pktin.type));
crReturnV;
}
/*
* We failed to start the command. If this is the
* fallback command, we really are finished; if it's
* not, and if the fallback command exists, try falling
* back to it before complaining.
*/
if (!ssh_fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
logevent("Primary command failed; attempting fallback");
ssh_fallback_cmd = TRUE;
continue;
}
bombout(("Server refused to start a shell/command"));
crReturnV;
} else {
logevent("Started a shell/command");
}
break;
}
ssh_state = SSH_STATE_SESSION;
if (size_needed)
ssh_size();
if (eof_needed)
ssh_special(TS_EOF);
/*
* Transfer data!
*/
ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */
ssh_send_ok = 1;
while (1) {
static int try_send;
crReturnV;
try_send = FALSE;
if (ispkt) {
if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
char *data;
int length;
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
continue; /* extended but not stderr */
ssh2_pkt_getstring(&data, &length);
if (data) {
int bufsize;
c->v.v2.locwindow -= length;
switch (c->type) {
case CHAN_MAINSESSION:
bufsize =
from_backend(pktin.type ==
SSH2_MSG_CHANNEL_EXTENDED_DATA,
data, length);
break;
case CHAN_X11:
bufsize = x11_send(c->u.x11.s, data, length);
break;
case CHAN_SOCKDATA:
bufsize = pfd_send(c->u.pfd.s, data, length);
break;
case CHAN_AGENT:
while (length > 0) {
if (c->u.a.lensofar < 4) {
int l = min(4 - c->u.a.lensofar, length);
memcpy(c->u.a.msglen + c->u.a.lensofar,
data, l);
data += l;
length -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == 4) {
c->u.a.totallen =
4 + GET_32BIT(c->u.a.msglen);
c->u.a.message = smalloc(c->u.a.totallen);
memcpy(c->u.a.message, c->u.a.msglen, 4);
}
if (c->u.a.lensofar >= 4 && length > 0) {
int l =
min(c->u.a.totallen - c->u.a.lensofar,
length);
memcpy(c->u.a.message + c->u.a.lensofar,
data, l);
data += l;
length -= l;
c->u.a.lensofar += l;
}
if (c->u.a.lensofar == c->u.a.totallen) {
void *reply, *sentreply;
int replylen;
agent_query(c->u.a.message,
c->u.a.totallen, &reply,
&replylen);
if (reply)
sentreply = reply;
else {
/* Fake SSH_AGENT_FAILURE. */
sentreply = "\0\0\0\1\5";
replylen = 5;
}
ssh2_add_channel_data(c, sentreply,
replylen);
try_send = TRUE;
if (reply)
sfree(reply);
sfree(c->u.a.message);
c->u.a.lensofar = 0;
}
}
bufsize = 0;
break;
}
/*
* If we are not buffering too much data,
* enlarge the window again at the remote side.
*/
if (bufsize < OUR_V2_WINSIZE)
ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
}
} else if (pktin.type == SSH2_MSG_DISCONNECT) {
ssh_state = SSH_STATE_CLOSED;
logevent("Received disconnect message");
crReturnV;
} else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
continue; /* exit status et al; ignore (FIXME?) */
} else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
if (c->type == CHAN_X11) {
/*
* Remote EOF on an X11 channel means we should
* wrap up and close the channel ourselves.
*/
x11_close(c->u.x11.s);
sshfwd_close(c);
} else if (c->type == CHAN_AGENT) {
sshfwd_close(c);
} else if (c->type == CHAN_SOCKDATA) {
pfd_close(c->u.pfd.s);
sshfwd_close(c);
}
} else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
/* Do pre-close processing on the channel. */
switch (c->type) {
case CHAN_MAINSESSION:
break; /* nothing to see here, move along */
case CHAN_X11:
if (c->u.x11.s != NULL)
x11_close(c->u.x11.s);
sshfwd_close(c);
break;
case CHAN_AGENT:
sshfwd_close(c);
break;
case CHAN_SOCKDATA:
if (c->u.pfd.s != NULL)
pfd_close(c->u.pfd.s);
sshfwd_close(c);
break;
}
if (c->closes == 0) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_send();
}
del234(ssh_channels, c);
bufchain_clear(&c->v.v2.outbuffer);
sfree(c);
/*
* See if that was the last channel left open.
*/
if (count234(ssh_channels) == 0) {
logevent("All channels closed. Disconnecting");
ssh2_pkt_init(SSH2_MSG_DISCONNECT);
ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
ssh2_pkt_addstring("All open channels closed");
ssh2_pkt_addstring("en"); /* language tag */
ssh2_pkt_send();
ssh_state = SSH_STATE_CLOSED;
crReturnV;
}
continue; /* remote sends close; ignore (FIXME) */
} else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
c->v.v2.remwindow += ssh2_pkt_getuint32();
try_send = TRUE;
} else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
if (c->type != CHAN_SOCKDATA_DORMANT)
continue; /* dunno why they're confirming this */
c->remoteid = ssh2_pkt_getuint32();
c->type = CHAN_SOCKDATA;
c->closes = 0;
c->v.v2.remwindow = ssh2_pkt_getuint32();
c->v.v2.remmaxpkt = ssh2_pkt_getuint32();
bufchain_init(&c->v.v2.outbuffer);
pfd_confirm(c->u.pfd.s);
} else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
c = find234(ssh_channels, &i, ssh_channelfind);
if (!c)
continue; /* nonexistent channel */
if (c->type != CHAN_SOCKDATA_DORMANT)
continue; /* dunno why they're failing this */
logevent("Forwarded connection refused by server");
pfd_close(c->u.pfd.s);
del234(ssh_channels, c);
sfree(c);
} else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
char *type;
int typelen;
char *error = NULL;
struct ssh_channel *c;
unsigned remid, winsize, pktsize;
ssh2_pkt_getstring(&type, &typelen);
c = smalloc(sizeof(struct ssh_channel));
remid = ssh2_pkt_getuint32();
winsize = ssh2_pkt_getuint32();
pktsize = ssh2_pkt_getuint32();
if (typelen == 3 && !memcmp(type, "x11", 3)) {
if (!ssh_X11_fwd_enabled)
error = "X11 forwarding is not enabled";
else if (x11_init(&c->u.x11.s, cfg.x11_display, c) !=
NULL) {
error = "Unable to open an X11 connection";
} else {
c->type = CHAN_X11;
}
} else if (typelen == 15 &&
!memcmp(type, "forwarded-tcpip", 15)) {
struct ssh_rportfwd pf, *realpf;
char *dummy;
int dummylen;
ssh2_pkt_getstring(&dummy, &dummylen);/* skip address */
pf.sport = ssh2_pkt_getuint32();
realpf = find234(ssh_rportfwds, &pf, NULL);
if (realpf == NULL) {
error = "Remote port is not recognised";
} else {
char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
realpf->dport, c);
char buf[1024];
sprintf(buf, "Received remote port open request for %s:%d",
realpf->dhost, realpf->dport);
logevent(buf);
if (e != NULL) {
sprintf(buf, "Port open failed: %s", e);
logevent(buf);
error = "Port open failed";
} else {
logevent("Forwarded port opened successfully");
c->type = CHAN_SOCKDATA;
}
}
} else if (typelen == 22 &&
!memcmp(type, "auth-agent@openssh.com", 3)) {
if (!ssh_agentfwd_enabled)
error = "Agent forwarding is not enabled";
else {
c->type = CHAN_AGENT; /* identify channel type */
c->u.a.lensofar = 0;
}
} else {
error = "Unsupported channel type requested";
}
c->remoteid = remid;
if (error) {
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
ssh2_pkt_addstring(error);
ssh2_pkt_addstring("en"); /* language tag */
ssh2_pkt_send();
sfree(c);
} else {
c->localid = alloc_channel_id();
c->closes = 0;
c->v.v2.locwindow = OUR_V2_WINSIZE;
c->v.v2.remwindow = winsize;
c->v.v2.remmaxpkt = pktsize;
bufchain_init(&c->v.v2.outbuffer);
add234(ssh_channels, c);
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
ssh2_pkt_adduint32(c->remoteid);
ssh2_pkt_adduint32(c->localid);
ssh2_pkt_adduint32(c->v.v2.locwindow);
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
ssh2_pkt_send();
}
} else {
bombout(("Strange packet received: type %d", pktin.type));
crReturnV;
}
} else {
/*
* We have spare data. Add it to the channel buffer.
*/
ssh2_add_channel_data(mainchan, in, inlen);
try_send = TRUE;
}
if (try_send) {
int i;
struct ssh_channel *c;
/*
* Try to send data on all channels if we can.
*/
for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) {
int bufsize = ssh2_try_send(c);
if (bufsize == 0) {
switch (c->type) {
case CHAN_MAINSESSION:
/* stdin need not receive an unthrottle
* notification since it will be polled */
break;
case CHAN_X11:
x11_unthrottle(c->u.x11.s);
break;
case CHAN_AGENT:
/* agent sockets are request/response and need no
* buffer management */
break;
case CHAN_SOCKDATA:
pfd_unthrottle(c->u.pfd.s);
break;
}
}
}
}
}
crFinishV;
}
/*
* Handle the top-level SSH2 protocol.
*/
static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
{
if (do_ssh2_transport(in, inlen, ispkt) == 0)
return;
do_ssh2_authconn(in, inlen, ispkt);
}
/*
* Called to set up the connection.
*
* Returns an error message, or NULL on success.
*/
static char *ssh_init(char *host, int port, char **realhost)
{
char *p;
#ifdef MSCRYPTOAPI
if (crypto_startup() == 0)
return "Microsoft high encryption pack not installed!";
#endif
ssh_send_ok = 0;
ssh_editing = 0;
ssh_echoing = 0;
ssh1_throttle_count = 0;
ssh_overall_bufsize = 0;
ssh_fallback_cmd = 0;
p = connect_to_host(host, port, realhost);
if (p != NULL)
return p;
return NULL;
}
/*
* Called to send data down the Telnet connection.
*/
static int ssh_send(char *buf, int len)
{
if (s == NULL || ssh_protocol == NULL)
return 0;
ssh_protocol(buf, len, 0);
return ssh_sendbuffer();
}
/*
* Called to query the current amount of buffered stdin data.
*/
static int ssh_sendbuffer(void)
{
int override_value;
if (s == NULL || ssh_protocol == NULL)
return 0;
/*
* If the SSH socket itself has backed up, add the total backup
* size on that to any individual buffer on the stdin channel.
*/
override_value = 0;
if (ssh_throttled_all)
override_value = ssh_overall_bufsize;
if (ssh_version == 1) {
return override_value;
} else if (ssh_version == 2) {
if (!mainchan || mainchan->closes > 0)
return override_value;
else
return override_value + bufchain_size(&mainchan->v.v2.outbuffer);
}
return 0;
}
/*
* Called to set the size of the window from SSH's POV.
*/
static void ssh_size(void)
{
switch (ssh_state) {
case SSH_STATE_BEFORE_SIZE:
case SSH_STATE_PREPACKET:
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) {
if (ssh_version == 1) {
send_packet(SSH1_CMSG_WINDOW_SIZE,
PKT_INT, rows, PKT_INT, cols,
PKT_INT, 0, PKT_INT, 0, PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_addstring("window-change");
ssh2_pkt_addbool(0);
ssh2_pkt_adduint32(cols);
ssh2_pkt_adduint32(rows);
ssh2_pkt_adduint32(0);
ssh2_pkt_adduint32(0);
ssh2_pkt_send();
}
}
break;
}
}
/*
* Send Telnet special codes. TS_EOF is useful for `plink', so you
* can send an EOF and collect resulting output (e.g. `plink
* hostname sort').
*/
static void ssh_special(Telnet_Special code)
{
if (code == TS_EOF) {
if (ssh_state != SSH_STATE_SESSION) {
/*
* Buffer the EOF in case we are pre-SESSION, so we can
* send it as soon as we reach SESSION.
*/
if (code == TS_EOF)
eof_needed = TRUE;
return;
}
if (ssh_version == 1) {
send_packet(SSH1_CMSG_EOF, PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
ssh2_pkt_adduint32(mainchan->remoteid);
ssh2_pkt_send();
}
logevent("Sent EOF message");
} else if (code == TS_PING) {
if (ssh_state == SSH_STATE_CLOSED
|| ssh_state == SSH_STATE_PREPACKET) return;
if (ssh_version == 1) {
send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_IGNORE);
ssh2_pkt_addstring_start();
ssh2_pkt_send();
}
} else {
/* do nothing */
}
}
void *new_sock_channel(Socket s)
{
struct ssh_channel *c;
c = smalloc(sizeof(struct ssh_channel));
if (c) {
c->remoteid = -1; /* to be set when open confirmed */
c->localid = alloc_channel_id();
c->closes = 0;
c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
c->u.pfd.s = s;
add234(ssh_channels, c);
}
return c;
}
/*
* This is called when stdout/stderr (the entity to which
* from_backend sends data) manages to clear some backlog.
*/
void ssh_unthrottle(int bufsize)
{
if (ssh_version == 1) {
if (ssh1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
ssh1_stdout_throttling = 0;
ssh1_throttle(-1);
}
} else {
if (mainchan && mainchan->closes == 0)
ssh2_set_window(mainchan, OUR_V2_WINSIZE - bufsize);
}
}
void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
{
struct ssh_channel *c = (struct ssh_channel *)channel;
char buf[1024];
sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port);
logevent(buf);
if (ssh_version == 1) {
send_packet(SSH1_MSG_PORT_OPEN,
PKT_INT, c->localid,
PKT_STR, hostname,
PKT_INT, port,
//PKT_STR, <org:orgport>,
PKT_END);
} else {
ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
ssh2_pkt_addstring("direct-tcpip");
ssh2_pkt_adduint32(c->localid);
c->v.v2.locwindow = OUR_V2_WINSIZE;
ssh2_pkt_adduint32(c->v.v2.locwindow);/* our window size */
ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
ssh2_pkt_addstring(hostname);
ssh2_pkt_adduint32(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.
*/
ssh2_pkt_addstring("client-side-connection");
ssh2_pkt_adduint32(0);
ssh2_pkt_send();
}
}
static Socket ssh_socket(void)
{
return s;
}
static int ssh_sendok(void)
{
return ssh_send_ok;
}
static int ssh_ldisc(int option)
{
if (option == LD_ECHO)
return ssh_echoing;
if (option == LD_EDIT)
return ssh_editing;
return FALSE;
}
Backend ssh_backend = {
ssh_init,
ssh_send,
ssh_sendbuffer,
ssh_size,
ssh_special,
ssh_socket,
ssh_sendok,
ssh_ldisc,
ssh_unthrottle,
22
};