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3214563d8e
putty-source/portfwd.c
Simon Tatham 3214563d8e Convert a lot of 'int' variables to 'bool'. 
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.

PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.

I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!

To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.

In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
 - the 'multisel' field in dialog.h's list box structure, for which
   the GTK front end in particular recognises a difference between 1
   and 2 but nearly everything else treats as boolean
 - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
   something about the specific location of the urgent pointer, but
   most clients only care about 0 vs 'something nonzero'
 - the return value of wc_match, where -1 indicates a syntax error in
   the wildcard.
 - the return values from SSH-1 RSA-key loading functions, which use
   -1 for 'wrong passphrase' and 0 for all other failures (so any
   caller which already knows it's not loading an _encrypted private_
   key can treat them as boolean)
 - term->esc_query, and the 'query' parameter in toggle_mode in
   terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
   but can also hold -1 for some other intervening character that we
   don't support.

In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
 - the return value of plug_accepting uses the POSIXish convention of
   0=success and nonzero=error; I think if I made it bool then I'd
   also want to reverse its sense, and that's a job for a separate
   piece of work.
 - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
   represent the default and alternate screens. There's no obvious
   reason why one of those should be considered 'true' or 'positive'
   or 'success' - they're just indices - so I've left it as int.

ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.

In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.

Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-03 13:45:00 +00:00

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/*
* SSH port forwarding.
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "putty.h"
#include "ssh.h"
#include "sshchan.h"
/*
* Enumeration of values that live in the 'socks_state' field of
* struct PortForwarding.
*/
typedef enum {
SOCKS_NONE, /* direct connection (no SOCKS, or SOCKS already done) */
SOCKS_INITIAL, /* don't know if we're SOCKS 4 or 5 yet */
SOCKS_4, /* expect a SOCKS 4 (or 4A) connection message */
SOCKS_5_INITIAL, /* expect a SOCKS 5 preliminary message */
SOCKS_5_CONNECT /* expect a SOCKS 5 connection message */
} SocksState;
typedef struct PortForwarding {
SshChannel *c; /* channel structure held by SSH connection layer */
ConnectionLayer *cl; /* the connection layer itself */
/* Note that ssh need not be filled in if c is non-NULL */
Socket *s;
bool input_wanted;
bool ready;
SocksState socks_state;
/*
* `hostname' and `port' are the real hostname and port, once
* we know what we're connecting to.
*/
char *hostname;
int port;
/*
* `socksbuf' is the buffer we use to accumulate the initial SOCKS
* segment of the incoming data, plus anything after that that we
* receive before we're ready to send data to the SSH server.
*/
strbuf *socksbuf;
size_t socksbuf_consumed;
Plug plug;
Channel chan;
} PortForwarding;
struct PortListener {
ConnectionLayer *cl;
Socket *s;
bool is_dynamic;
/*
* `hostname' and `port' are the real hostname and port, for
* ordinary forwardings.
*/
char *hostname;
int port;
Plug plug;
};
static struct PortForwarding *new_portfwd_state(void)
{
struct PortForwarding *pf = snew(struct PortForwarding);
pf->hostname = NULL;
pf->socksbuf = NULL;
return pf;
}
static void free_portfwd_state(struct PortForwarding *pf)
{
if (!pf)
return;
sfree(pf->hostname);
if (pf->socksbuf)
strbuf_free(pf->socksbuf);
sfree(pf);
}
static struct PortListener *new_portlistener_state(void)
{
struct PortListener *pl = snew(struct PortListener);
pl->hostname = NULL;
return pl;
}
static void free_portlistener_state(struct PortListener *pl)
{
if (!pl)
return;
sfree(pl->hostname);
sfree(pl);
}
static void pfd_log(Plug *plug, int type, SockAddr *addr, int port,
const char *error_msg, int error_code)
{
/* we have to dump these since we have no interface to logging.c */
}
static void pfl_log(Plug *plug, int type, SockAddr *addr, int port,
const char *error_msg, int error_code)
{
/* we have to dump these since we have no interface to logging.c */
}
static void pfd_close(struct PortForwarding *pf);
static void pfd_closing(Plug *plug, const char *error_msg, int error_code,
bool calling_back)
{
struct PortForwarding *pf =
container_of(plug, struct PortForwarding, plug);
if (error_msg) {
/*
* Socket error. Slam the connection instantly shut.
*/
if (pf->c) {
sshfwd_initiate_close(pf->c, error_msg);
} else {
/*
* We might not have an SSH channel, if a socket error
* occurred during SOCKS negotiation. If not, we must
* clean ourself up without sshfwd_initiate_close's call
* back to pfd_close.
*/
pfd_close(pf);
}
} else {
/*
* Ordinary EOF received on socket. Send an EOF on the SSH
* channel.
*/
if (pf->c)
sshfwd_write_eof(pf->c);
}
}
static void pfl_terminate(struct PortListener *pl);
static void pfl_closing(Plug *plug, const char *error_msg, int error_code,
bool calling_back)
{
struct PortListener *pl = (struct PortListener *) plug;
pfl_terminate(pl);
}
static SshChannel *wrap_lportfwd_open(
ConnectionLayer *cl, const char *hostname, int port,
Socket *s, Channel *chan)
{
SocketPeerInfo *pi;
char *description;
SshChannel *toret;
pi = sk_peer_info(s);
if (pi && pi->log_text) {
description = dupprintf("forwarding from %s", pi->log_text);
} else {
description = dupstr("forwarding");
}
toret = ssh_lportfwd_open(cl, hostname, port, description, pi, chan);
sk_free_peer_info(pi);
sfree(description);
return toret;
}
static char *ipv4_to_string(unsigned ipv4)
{
return dupprintf("%u.%u.%u.%u",
(ipv4 >> 24) & 0xFF, (ipv4 >> 16) & 0xFF,
(ipv4 >> 8) & 0xFF, (ipv4 ) & 0xFF);
}
static char *ipv6_to_string(ptrlen ipv6)
{
const unsigned char *addr = ipv6.ptr;
assert(ipv6.len == 16);
return dupprintf("%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x",
(unsigned)GET_16BIT_MSB_FIRST(addr + 0),
(unsigned)GET_16BIT_MSB_FIRST(addr + 2),
(unsigned)GET_16BIT_MSB_FIRST(addr + 4),
(unsigned)GET_16BIT_MSB_FIRST(addr + 6),
(unsigned)GET_16BIT_MSB_FIRST(addr + 8),
(unsigned)GET_16BIT_MSB_FIRST(addr + 10),
(unsigned)GET_16BIT_MSB_FIRST(addr + 12),
(unsigned)GET_16BIT_MSB_FIRST(addr + 14));
}
static void pfd_receive(Plug *plug, int urgent, char *data, int len)
{
struct PortForwarding *pf =
container_of(plug, struct PortForwarding, plug);
if (len == 0)
return;
if (pf->socks_state != SOCKS_NONE) {
BinarySource src[1];
/*
* Store all the data we've got in socksbuf.
*/
put_data(pf->socksbuf, data, len);
/*
* Check the start of socksbuf to see if it's a valid and
* complete message in the SOCKS exchange.
*/
if (pf->socks_state == SOCKS_INITIAL) {
/* Preliminary: check the first byte of the data (which we
* _must_ have by now) to find out which SOCKS major
* version we're speaking. */
switch (pf->socksbuf->u[0]) {
case 4:
pf->socks_state = SOCKS_4;
break;
case 5:
pf->socks_state = SOCKS_5_INITIAL;
break;
default:
pfd_close(pf); /* unrecognised version */
return;
}
}
BinarySource_BARE_INIT(src, pf->socksbuf->u, pf->socksbuf->len);
get_data(src, pf->socksbuf_consumed);
while (pf->socks_state != SOCKS_NONE) {
unsigned socks_version, message_type, reserved_byte;
unsigned reply_code, port, ipv4, method;
ptrlen methods;
const char *socks4_hostname;
strbuf *output;
switch (pf->socks_state) {
case SOCKS_INITIAL:
case SOCKS_NONE:
assert(0 && "These case values cannot appear");
case SOCKS_4:
/* SOCKS 4/4A connect message */
socks_version = get_byte(src);
message_type = get_byte(src);
if (get_err(src) == BSE_OUT_OF_DATA)
return;
if (socks_version == 4 && message_type == 1) {
/* CONNECT message */
bool name_based = false;
port = get_uint16(src);
ipv4 = get_uint32(src);
if (ipv4 > 0x00000000 && ipv4 < 0x00000100) {
/*
* Addresses in this range indicate the SOCKS 4A
* extension to specify a hostname, which comes
* after the username.
*/
name_based = true;
}
get_asciz(src); /* skip username */
socks4_hostname = name_based ? get_asciz(src) : NULL;
if (get_err(src) == BSE_OUT_OF_DATA)
return;
if (get_err(src))
goto socks4_reject;
pf->port = port;
if (name_based) {
pf->hostname = dupstr(socks4_hostname);
} else {
pf->hostname = ipv4_to_string(ipv4);
}
output = strbuf_new();
put_byte(output, 0); /* reply version */
put_byte(output, 90); /* SOCKS 4 'request granted' */
put_uint16(output, 0); /* null port field */
put_uint32(output, 0); /* null address field */
sk_write(pf->s, output->u, output->len);
strbuf_free(output);
pf->socks_state = SOCKS_NONE;
pf->socksbuf_consumed = src->pos;
break;
}
socks4_reject:
output = strbuf_new();
put_byte(output, 0); /* reply version */
put_byte(output, 91); /* SOCKS 4 'request rejected' */
put_uint16(output, 0); /* null port field */
put_uint32(output, 0); /* null address field */
sk_write(pf->s, output->u, output->len);
strbuf_free(output);
pfd_close(pf);
return;
case SOCKS_5_INITIAL:
/* SOCKS 5 initial method list */
socks_version = get_byte(src);
methods = get_pstring(src);
method = 0xFF; /* means 'no usable method found' */
{
int i;
for (i = 0; i < methods.len; i++) {
if (((const unsigned char *)methods.ptr)[i] == 0 ) {
method = 0; /* no auth */
break;
}
}
}
if (get_err(src) == BSE_OUT_OF_DATA)
return;
if (get_err(src))
method = 0xFF;
output = strbuf_new();
put_byte(output, 5); /* SOCKS version */
put_byte(output, method); /* selected auth method */
sk_write(pf->s, output->u, output->len);
strbuf_free(output);
if (method == 0xFF) {
pfd_close(pf);
return;
}
pf->socks_state = SOCKS_5_CONNECT;
pf->socksbuf_consumed = src->pos;
break;
case SOCKS_5_CONNECT:
/* SOCKS 5 connect message */
socks_version = get_byte(src);
message_type = get_byte(src);
reserved_byte = get_byte(src);
if (socks_version == 5 && message_type == 1 &&
reserved_byte == 0) {
reply_code = 0; /* success */
switch (get_byte(src)) {
case 1: /* IPv4 */
pf->hostname = ipv4_to_string(get_uint32(src));
break;
case 4: /* IPv6 */
pf->hostname = ipv6_to_string(get_data(src, 16));
break;
case 3: /* unresolved domain name */
pf->hostname = mkstr(get_pstring(src));
break;
default:
pf->hostname = NULL;
reply_code = 8; /* address type not supported */
break;
}
pf->port = get_uint16(src);
} else {
reply_code = 7; /* command not supported */
}
if (get_err(src) == BSE_OUT_OF_DATA)
return;
if (get_err(src))
reply_code = 1; /* general server failure */
output = strbuf_new();
put_byte(output, 5); /* SOCKS version */
put_byte(output, reply_code);
put_byte(output, 0); /* reserved */
put_byte(output, 1); /* IPv4 address follows */
put_uint32(output, 0); /* bound IPv4 address (unused) */
put_uint16(output, 0); /* bound port number (unused) */
sk_write(pf->s, output->u, output->len);
strbuf_free(output);
if (reply_code != 0) {
pfd_close(pf);
return;
}
pf->socks_state = SOCKS_NONE;
pf->socksbuf_consumed = src->pos;
break;
}
}
/*
* We come here when we're ready to make an actual
* connection.
*/
/*
* Freeze the socket until the SSH server confirms the
* connection.
*/
sk_set_frozen(pf->s, 1);
pf->c = wrap_lportfwd_open(pf->cl, pf->hostname, pf->port, pf->s,
&pf->chan);
}
if (pf->ready)
sshfwd_write(pf->c, data, len);
}
static void pfd_sent(Plug *plug, int bufsize)
{
struct PortForwarding *pf =
container_of(plug, struct PortForwarding, plug);
if (pf->c)
sshfwd_unthrottle(pf->c, bufsize);
}
static const PlugVtable PortForwarding_plugvt = {
pfd_log,
pfd_closing,
pfd_receive,
pfd_sent,
NULL
};
static void pfd_chan_free(Channel *chan);
static void pfd_open_confirmation(Channel *chan);
static void pfd_open_failure(Channel *chan, const char *errtext);
static int pfd_send(Channel *chan, bool is_stderr, const void *data, int len);
static void pfd_send_eof(Channel *chan);
static void pfd_set_input_wanted(Channel *chan, bool wanted);
static char *pfd_log_close_msg(Channel *chan);
static const struct ChannelVtable PortForwarding_channelvt = {
pfd_chan_free,
pfd_open_confirmation,
pfd_open_failure,
pfd_send,
pfd_send_eof,
pfd_set_input_wanted,
pfd_log_close_msg,
chan_default_want_close,
chan_no_exit_status,
chan_no_exit_signal,
chan_no_exit_signal_numeric,
chan_no_run_shell,
chan_no_run_command,
chan_no_run_subsystem,
chan_no_enable_x11_forwarding,
chan_no_enable_agent_forwarding,
chan_no_allocate_pty,
chan_no_set_env,
chan_no_send_break,
chan_no_send_signal,
chan_no_change_window_size,
chan_no_request_response,
};
Channel *portfwd_raw_new(ConnectionLayer *cl, Plug **plug)
{
struct PortForwarding *pf;
pf = new_portfwd_state();
pf->plug.vt = &PortForwarding_plugvt;
pf->chan.initial_fixed_window_size = 0;
pf->chan.vt = &PortForwarding_channelvt;
pf->input_wanted = true;
pf->c = NULL;
pf->cl = cl;
pf->input_wanted = true;
pf->ready = false;
pf->socks_state = SOCKS_NONE;
pf->hostname = NULL;
pf->port = 0;
*plug = &pf->plug;
return &pf->chan;
}
void portfwd_raw_free(Channel *pfchan)
{
struct PortForwarding *pf;
assert(pfchan->vt == &PortForwarding_channelvt);
pf = container_of(pfchan, struct PortForwarding, chan);
free_portfwd_state(pf);
}
void portfwd_raw_setup(Channel *pfchan, Socket *s, SshChannel *sc)
{
struct PortForwarding *pf;
assert(pfchan->vt == &PortForwarding_channelvt);
pf = container_of(pfchan, struct PortForwarding, chan);
pf->s = s;
pf->c = sc;
}
/*
called when someone connects to the local port
*/
static int pfl_accepting(Plug *p, accept_fn_t constructor, accept_ctx_t ctx)
{
struct PortListener *pl = container_of(p, struct PortListener, plug);
struct PortForwarding *pf;
Channel *chan;
Plug *plug;
Socket *s;
const char *err;
chan = portfwd_raw_new(pl->cl, &plug);
s = constructor(ctx, plug);
if ((err = sk_socket_error(s)) != NULL) {
portfwd_raw_free(chan);
return 1;
}
pf = container_of(chan, struct PortForwarding, chan);
if (pl->is_dynamic) {
pf->s = s;
pf->socks_state = SOCKS_INITIAL;
pf->socksbuf = strbuf_new();
pf->socksbuf_consumed = 0;
pf->port = 0; /* "hostname" buffer is so far empty */
sk_set_frozen(s, 0); /* we want to receive SOCKS _now_! */
} else {
pf->hostname = dupstr(pl->hostname);
pf->port = pl->port;
portfwd_raw_setup(
chan, s,
wrap_lportfwd_open(pl->cl, pf->hostname, pf->port, s, &pf->chan));
}
return 0;
}
static const PlugVtable PortListener_plugvt = {
pfl_log,
pfl_closing,
NULL, /* recv */
NULL, /* send */
pfl_accepting
};
/*
* Add a new port-forwarding listener from srcaddr:port -> desthost:destport.
*
* desthost == NULL indicates dynamic SOCKS port forwarding.
*
* On success, returns NULL and fills in *pl_ret. On error, returns a
* dynamically allocated error message string.
*/
static char *pfl_listen(const char *desthost, int destport,
const char *srcaddr, int port,
ConnectionLayer *cl, Conf *conf,
struct PortListener **pl_ret, int address_family)
{
const char *err;
struct PortListener *pl;
/*
* Open socket.
*/
pl = *pl_ret = new_portlistener_state();
pl->plug.vt = &PortListener_plugvt;
if (desthost) {
pl->hostname = dupstr(desthost);
pl->port = destport;
pl->is_dynamic = false;
} else
pl->is_dynamic = true;
pl->cl = cl;
pl->s = new_listener(srcaddr, port, &pl->plug,
!conf_get_bool(conf, CONF_lport_acceptall),
conf, address_family);
if ((err = sk_socket_error(pl->s)) != NULL) {
char *err_ret = dupstr(err);
sk_close(pl->s);
free_portlistener_state(pl);
*pl_ret = NULL;
return err_ret;
}
return NULL;
}
static char *pfd_log_close_msg(Channel *chan)
{
return dupstr("Forwarded port closed");
}
static void pfd_close(struct PortForwarding *pf)
{
if (!pf)
return;
sk_close(pf->s);
free_portfwd_state(pf);
}
/*
* Terminate a listener.
*/
static void pfl_terminate(struct PortListener *pl)
{
if (!pl)
return;
sk_close(pl->s);
free_portlistener_state(pl);
}
static void pfd_set_input_wanted(Channel *chan, bool wanted)
{
assert(chan->vt == &PortForwarding_channelvt);
PortForwarding *pf = container_of(chan, PortForwarding, chan);
pf->input_wanted = wanted;
sk_set_frozen(pf->s, !pf->input_wanted);
}
static void pfd_chan_free(Channel *chan)
{
assert(chan->vt == &PortForwarding_channelvt);
PortForwarding *pf = container_of(chan, PortForwarding, chan);
pfd_close(pf);
}
/*
* Called to send data down the raw connection.
*/
static int pfd_send(Channel *chan, bool is_stderr, const void *data, int len)
{
assert(chan->vt == &PortForwarding_channelvt);
PortForwarding *pf = container_of(chan, PortForwarding, chan);
return sk_write(pf->s, data, len);
}
static void pfd_send_eof(Channel *chan)
{
assert(chan->vt == &PortForwarding_channelvt);
PortForwarding *pf = container_of(chan, PortForwarding, chan);
sk_write_eof(pf->s);
}
static void pfd_open_confirmation(Channel *chan)
{
assert(chan->vt == &PortForwarding_channelvt);
PortForwarding *pf = container_of(chan, PortForwarding, chan);
pf->ready = true;
sk_set_frozen(pf->s, 0);
sk_write(pf->s, NULL, 0);
if (pf->socksbuf) {
sshfwd_write(pf->c, pf->socksbuf->u + pf->socksbuf_consumed,
pf->socksbuf->len - pf->socksbuf_consumed);
strbuf_free(pf->socksbuf);
pf->socksbuf = NULL;
}
}
static void pfd_open_failure(Channel *chan, const char *errtext)
{
assert(chan->vt == &PortForwarding_channelvt);
PortForwarding *pf = container_of(chan, PortForwarding, chan);
logeventf(pf->cl->logctx,
"Forwarded connection refused by remote%s%s",
errtext ? ": " : "", errtext ? errtext : "");
}
/* ----------------------------------------------------------------------
* Code to manage the complete set of currently active port
* forwardings, and update it from Conf.
*/
struct PortFwdRecord {
enum { DESTROY, KEEP, CREATE } status;
int type;
unsigned sport, dport;
char *saddr, *daddr;
char *sserv, *dserv;
struct ssh_rportfwd *remote;
int addressfamily;
struct PortListener *local;
};
static int pfr_cmp(void *av, void *bv)
{
PortFwdRecord *a = (PortFwdRecord *) av;
PortFwdRecord *b = (PortFwdRecord *) bv;
int i;
if (a->type > b->type)
return +1;
if (a->type < b->type)
return -1;
if (a->addressfamily > b->addressfamily)
return +1;
if (a->addressfamily < b->addressfamily)
return -1;
if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
return i < 0 ? -1 : +1;
if (a->sport > b->sport)
return +1;
if (a->sport < b->sport)
return -1;
if (a->type != 'D') {
if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
return i < 0 ? -1 : +1;
if (a->dport > b->dport)
return +1;
if (a->dport < b->dport)
return -1;
}
return 0;
}
void pfr_free(PortFwdRecord *pfr)
{
/* Dispose of any listening socket. */
if (pfr->local)
pfl_terminate(pfr->local);
sfree(pfr->saddr);
sfree(pfr->daddr);
sfree(pfr->sserv);
sfree(pfr->dserv);
sfree(pfr);
}
struct PortFwdManager {
ConnectionLayer *cl;
Conf *conf;
tree234 *forwardings;
};
PortFwdManager *portfwdmgr_new(ConnectionLayer *cl)
{
PortFwdManager *mgr = snew(PortFwdManager);
mgr->cl = cl;
mgr->conf = NULL;
mgr->forwardings = newtree234(pfr_cmp);
return mgr;
}
void portfwdmgr_close(PortFwdManager *mgr, PortFwdRecord *pfr)
{
PortFwdRecord *realpfr = del234(mgr->forwardings, pfr);
if (realpfr == pfr)
pfr_free(pfr);
}
void portfwdmgr_close_all(PortFwdManager *mgr)
{
PortFwdRecord *pfr;
while ((pfr = delpos234(mgr->forwardings, 0)) != NULL)
pfr_free(pfr);
}
void portfwdmgr_free(PortFwdManager *mgr)
{
portfwdmgr_close_all(mgr);
freetree234(mgr->forwardings);
if (mgr->conf)
conf_free(mgr->conf);
sfree(mgr);
}
void portfwdmgr_config(PortFwdManager *mgr, Conf *conf)
{
PortFwdRecord *pfr;
int i;
char *key, *val;
if (mgr->conf)
conf_free(mgr->conf);
mgr->conf = conf_copy(conf);
/*
* Go through the existing port forwardings and tag them
* with status==DESTROY. Any that we want to keep will be
* re-enabled (status==KEEP) as we go through the
* configuration and find out which bits are the same as
* they were before.
*/
for (i = 0; (pfr = index234(mgr->forwardings, i)) != NULL; i++)
pfr->status = DESTROY;
for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
val != NULL;
val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
char *kp, *kp2, *vp, *vp2;
char address_family, type;
int sport, dport, sserv, dserv;
char *sports, *dports, *saddr, *host;
kp = key;
address_family = 'A';
type = 'L';
if (*kp == 'A' || *kp == '4' || *kp == '6')
address_family = *kp++;
if (*kp == 'L' || *kp == 'R')
type = *kp++;
if ((kp2 = host_strchr(kp, ':')) != NULL) {
/*
* There's a colon in the middle of the source port
* string, which means that the part before it is
* actually a source address.
*/
char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
saddr = host_strduptrim(saddr_tmp);
sfree(saddr_tmp);
sports = kp2+1;
} else {
saddr = NULL;
sports = kp;
}
sport = atoi(sports);
sserv = 0;
if (sport == 0) {
sserv = 1;
sport = net_service_lookup(sports);
if (!sport) {
logeventf(mgr->cl->logctx, "Service lookup failed for source"
" port \"%s\"", sports);
}
}
if (type == 'L' && !strcmp(val, "D")) {
/* dynamic forwarding */
host = NULL;
dports = NULL;
dport = -1;
dserv = 0;
type = 'D';
} else {
/* ordinary forwarding */
vp = val;
vp2 = vp + host_strcspn(vp, ":");
host = dupprintf("%.*s", (int)(vp2 - vp), vp);
if (*vp2)
vp2++;
dports = vp2;
dport = atoi(dports);
dserv = 0;
if (dport == 0) {
dserv = 1;
dport = net_service_lookup(dports);
if (!dport) {
logeventf(mgr->cl->logctx,
"Service lookup failed for destination"
" port \"%s\"", dports);
}
}
}
if (sport && dport) {
/* Set up a description of the source port. */
pfr = snew(PortFwdRecord);
pfr->type = type;
pfr->saddr = saddr;
pfr->sserv = sserv ? dupstr(sports) : NULL;
pfr->sport = sport;
pfr->daddr = host;
pfr->dserv = dserv ? dupstr(dports) : NULL;
pfr->dport = dport;
pfr->local = NULL;
pfr->remote = NULL;
pfr->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
address_family == '6' ? ADDRTYPE_IPV6 :
ADDRTYPE_UNSPEC);
PortFwdRecord *existing = add234(mgr->forwardings, pfr);
if (existing != pfr) {
if (existing->status == DESTROY) {
/*
* We already have a port forwarding up and running
* with precisely these parameters. Hence, no need
* to do anything; simply re-tag the existing one
* as KEEP.
*/
existing->status = KEEP;
}
/*
* Anything else indicates that there was a duplicate
* in our input, which we'll silently ignore.
*/
pfr_free(pfr);
} else {
pfr->status = CREATE;
}
} else {
sfree(saddr);
sfree(host);
}
}
/*
* Now go through and destroy any port forwardings which were
* not re-enabled.
*/
for (i = 0; (pfr = index234(mgr->forwardings, i)) != NULL; i++) {
if (pfr->status == DESTROY) {
char *message;
message = dupprintf("%s port forwarding from %s%s%d",
pfr->type == 'L' ? "local" :
pfr->type == 'R' ? "remote" : "dynamic",
pfr->saddr ? pfr->saddr : "",
pfr->saddr ? ":" : "",
pfr->sport);
if (pfr->type != 'D') {
char *msg2 = dupprintf("%s to %s:%d", message,
pfr->daddr, pfr->dport);
sfree(message);
message = msg2;
}
logeventf(mgr->cl->logctx, "Cancelling %s", message);
sfree(message);
/* pfr->remote or pfr->local may be NULL if setting up a
* forwarding failed. */
if (pfr->remote) {
/*
* Cancel the port forwarding at the server
* end.
*
* Actually closing the listening port on the server
* side may fail - because in SSH-1 there's no message
* in the protocol to request it!
*
* Instead, we simply remove the record of the
* forwarding from our local end, so that any
* connections the server tries to make on it are
* rejected.
*/
ssh_rportfwd_remove(mgr->cl, pfr->remote);
} else if (pfr->local) {
pfl_terminate(pfr->local);
}
delpos234(mgr->forwardings, i);
pfr_free(pfr);
i--; /* so we don't skip one in the list */
}
}
/*
* And finally, set up any new port forwardings (status==CREATE).
*/
for (i = 0; (pfr = index234(mgr->forwardings, i)) != NULL; i++) {
if (pfr->status == CREATE) {
char *sportdesc, *dportdesc;
sportdesc = dupprintf("%s%s%s%s%d%s",
pfr->saddr ? pfr->saddr : "",
pfr->saddr ? ":" : "",
pfr->sserv ? pfr->sserv : "",
pfr->sserv ? "(" : "",
pfr->sport,
pfr->sserv ? ")" : "");
if (pfr->type == 'D') {
dportdesc = NULL;
} else {
dportdesc = dupprintf("%s:%s%s%d%s",
pfr->daddr,
pfr->dserv ? pfr->dserv : "",
pfr->dserv ? "(" : "",
pfr->dport,
pfr->dserv ? ")" : "");
}
if (pfr->type == 'L') {
char *err = pfl_listen(pfr->daddr, pfr->dport,
pfr->saddr, pfr->sport,
mgr->cl, conf, &pfr->local,
pfr->addressfamily);
logeventf(mgr->cl->logctx,
"Local %sport %s forwarding to %s%s%s",
pfr->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
pfr->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
sportdesc, dportdesc,
err ? " failed: " : "", err ? err : "");
if (err)
sfree(err);
} else if (pfr->type == 'D') {
char *err = pfl_listen(NULL, -1, pfr->saddr, pfr->sport,
mgr->cl, conf, &pfr->local,
pfr->addressfamily);
logeventf(mgr->cl->logctx,
"Local %sport %s SOCKS dynamic forwarding%s%s",
pfr->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
pfr->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
sportdesc,
err ? " failed: " : "", err ? err : "");
if (err)
sfree(err);
} else {
const char *shost;
if (pfr->saddr) {
shost = pfr->saddr;
} else if (conf_get_bool(conf, CONF_rport_acceptall)) {
shost = "";
} else {
shost = "localhost";
}
pfr->remote = ssh_rportfwd_alloc(
mgr->cl, shost, pfr->sport, pfr->daddr, pfr->dport,
pfr->addressfamily, sportdesc, pfr, NULL);
if (!pfr->remote) {
logeventf(mgr->cl->logctx,
"Duplicate remote port forwarding to %s:%d",
pfr->daddr, pfr->dport);
pfr_free(pfr);
} else {
logeventf(mgr->cl->logctx, "Requesting remote port %s"
" forward to %s", sportdesc, dportdesc);
}
}
sfree(sportdesc);
sfree(dportdesc);
}
}
}
bool portfwdmgr_listen(PortFwdManager *mgr, const char *host, int port,
const char *keyhost, int keyport, Conf *conf)
{
PortFwdRecord *pfr;
pfr = snew(PortFwdRecord);
pfr->type = 'L';
pfr->saddr = host ? dupstr(host) : NULL;
pfr->daddr = keyhost ? dupstr(keyhost) : NULL;
pfr->sserv = pfr->dserv = NULL;
pfr->sport = port;
pfr->dport = keyport;
pfr->local = NULL;
pfr->remote = NULL;
pfr->addressfamily = ADDRTYPE_UNSPEC;
PortFwdRecord *existing = add234(mgr->forwardings, pfr);
if (existing != pfr) {
/*
* We had this record already. Return failure.
*/
pfr_free(pfr);
return false;
}
char *err = pfl_listen(keyhost, keyport, host, port,
mgr->cl, conf, &pfr->local, pfr->addressfamily);
logeventf(mgr->cl->logctx,
"%s on port %s:%d to forward to client%s%s",
err ? "Failed to listen" : "Listening", host, port,
err ? ": " : "", err ? err : "");
if (err) {
sfree(err);
del234(mgr->forwardings, pfr);
pfr_free(pfr);
return false;
}
return true;
}
bool portfwdmgr_unlisten(PortFwdManager *mgr, const char *host, int port)
{
PortFwdRecord pfr_key;
pfr_key.type = 'L';
/* Safe to cast the const away here, because it will only be used
* by pfr_cmp, which won't write to the string */
pfr_key.saddr = pfr_key.daddr = (char *)host;
pfr_key.sserv = pfr_key.dserv = NULL;
pfr_key.sport = pfr_key.dport = port;
pfr_key.local = NULL;
pfr_key.remote = NULL;
pfr_key.addressfamily = ADDRTYPE_UNSPEC;
PortFwdRecord *pfr = del234(mgr->forwardings, &pfr_key);
if (!pfr)
return false;
logeventf(mgr->cl->logctx, "Closing listening port %s:%d", host, port);
pfr_free(pfr);
return true;
}
/*
* Called when receiving a PORT OPEN from the server to make a
* connection to a destination host.
*
* On success, returns NULL and fills in *pf_ret. On error, returns a
* dynamically allocated error message string.
*/
char *portfwdmgr_connect(PortFwdManager *mgr, Channel **chan_ret,
char *hostname, int port, SshChannel *c,
int addressfamily)
{
SockAddr *addr;
const char *err;
char *dummy_realhost = NULL;
struct PortForwarding *pf;
/*
* Try to find host.
*/
addr = name_lookup(hostname, port, &dummy_realhost, mgr->conf,
addressfamily, NULL, NULL);
if ((err = sk_addr_error(addr)) != NULL) {
char *err_ret = dupstr(err);
sk_addr_free(addr);
sfree(dummy_realhost);
return err_ret;
}
/*
* Open socket.
*/
pf = new_portfwd_state();
*chan_ret = &pf->chan;
pf->plug.vt = &PortForwarding_plugvt;
pf->chan.initial_fixed_window_size = 0;
pf->chan.vt = &PortForwarding_channelvt;
pf->input_wanted = true;
pf->ready = true;
pf->c = c;
pf->cl = mgr->cl;
pf->socks_state = SOCKS_NONE;
pf->s = new_connection(addr, dummy_realhost, port,
false, true, false, false, &pf->plug, mgr->conf);
sfree(dummy_realhost);
if ((err = sk_socket_error(pf->s)) != NULL) {
char *err_ret = dupstr(err);
sk_close(pf->s);
free_portfwd_state(pf);
*chan_ret = NULL;
return err_ret;
}
return NULL;
}
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