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3214563d8e
putty-source/ssh2connection-client.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

479 lines
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/*
* Client-specific parts of the SSH-2 connection layer.
*/
#include <assert.h>
#include "putty.h"
#include "ssh.h"
#include "sshbpp.h"
#include "sshppl.h"
#include "sshchan.h"
#include "sshcr.h"
#include "ssh2connection.h"
static ChanopenResult chan_open_x11(
struct ssh2_connection_state *s, SshChannel *sc,
ptrlen peeraddr, int peerport)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
char *peeraddr_str;
Channel *ch;
ppl_logevent(("Received X11 connect request from %.*s:%d",
PTRLEN_PRINTF(peeraddr), peerport));
if (!s->X11_fwd_enabled && !s->connshare) {
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED,
("X11 forwarding is not enabled"));
}
peeraddr_str = peeraddr.ptr ? mkstr(peeraddr) : NULL;
ch = x11_new_channel(
s->x11authtree, sc, peeraddr_str, peerport, s->connshare != NULL);
sfree(peeraddr_str);
ppl_logevent(("Opened X11 forward channel"));
CHANOPEN_RETURN_SUCCESS(ch);
}
static ChanopenResult chan_open_forwarded_tcpip(
struct ssh2_connection_state *s, SshChannel *sc,
ptrlen fwdaddr, int fwdport, ptrlen peeraddr, int peerport)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
struct ssh_rportfwd pf, *realpf;
Channel *ch;
char *err;
ppl_logevent(("Received remote port %.*s:%d open request from %.*s:%d",
PTRLEN_PRINTF(fwdaddr), fwdport,
PTRLEN_PRINTF(peeraddr), peerport));
pf.shost = mkstr(fwdaddr);
pf.sport = fwdport;
realpf = find234(s->rportfwds, &pf, NULL);
sfree(pf.shost);
if (realpf == NULL) {
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED,
("Remote port is not recognised"));
}
if (realpf->share_ctx) {
/*
* This port forwarding is on behalf of a connection-sharing
* downstream.
*/
CHANOPEN_RETURN_DOWNSTREAM(realpf->share_ctx);
}
err = portfwdmgr_connect(
s->portfwdmgr, &ch, realpf->dhost, realpf->dport,
sc, realpf->addressfamily);
ppl_logevent(("Attempting to forward remote port to %s:%d",
realpf->dhost, realpf->dport));
if (err != NULL) {
ppl_logevent(("Port open failed: %s", err));
sfree(err);
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_CONNECT_FAILED,
("Port open failed"));
}
ppl_logevent(("Forwarded port opened successfully"));
CHANOPEN_RETURN_SUCCESS(ch);
}
static ChanopenResult chan_open_auth_agent(
struct ssh2_connection_state *s, SshChannel *sc)
{
if (!s->agent_fwd_enabled) {
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED,
("Agent forwarding is not enabled"));
}
CHANOPEN_RETURN_SUCCESS(agentf_new(sc));
}
ChanopenResult ssh2_connection_parse_channel_open(
struct ssh2_connection_state *s, ptrlen type,
PktIn *pktin, SshChannel *sc)
{
if (ptrlen_eq_string(type, "x11")) {
ptrlen peeraddr = get_string(pktin);
int peerport = get_uint32(pktin);
return chan_open_x11(s, sc, peeraddr, peerport);
} else if (ptrlen_eq_string(type, "forwarded-tcpip")) {
ptrlen fwdaddr = get_string(pktin);
int fwdport = toint(get_uint32(pktin));
ptrlen peeraddr = get_string(pktin);
int peerport = toint(get_uint32(pktin));
return chan_open_forwarded_tcpip(
s, sc, fwdaddr, fwdport, peeraddr, peerport);
} else if (ptrlen_eq_string(type, "auth-agent@openssh.com")) {
return chan_open_auth_agent(s, sc);
} else {
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_UNKNOWN_CHANNEL_TYPE,
("Unsupported channel type requested"));
}
}
bool ssh2_connection_parse_global_request(
struct ssh2_connection_state *s, ptrlen type, PktIn *pktin)
{
/*
* We don't know of any global requests that an SSH client needs
* to honour.
*/
return false;
}
PktOut *ssh2_portfwd_chanopen(
struct ssh2_connection_state *s, struct ssh2_channel *c,
const char *hostname, int port,
const char *description, const SocketPeerInfo *peerinfo)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
PktOut *pktout;
/*
* In client mode, this function is called by portfwdmgr in
* response to PortListeners that were set up in
* portfwdmgr_config, which means that the hostname and port
* parameters will indicate the host we want to tell the server to
* connect _to_.
*/
ppl_logevent(("Opening connection to %s:%d for %s",
hostname, port, description));
pktout = ssh2_chanopen_init(c, "direct-tcpip");
{
char *trimmed_host = host_strduptrim(hostname);
put_stringz(pktout, trimmed_host);
sfree(trimmed_host);
}
put_uint32(pktout, 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. The "originator IP address" is syntactically a
* numeric IP address, and some servers (e.g., Tectia) get upset
* if it doesn't match this syntax.
*/
put_stringz(pktout, "0.0.0.0");
put_uint32(pktout, 0);
return pktout;
}
static int ssh2_rportfwd_cmp(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->shost, b->shost)) != 0)
return i < 0 ? -1 : +1;
if (a->sport > b->sport)
return +1;
if (a->sport < b->sport)
return -1;
return 0;
}
static void ssh2_rportfwd_globreq_response(struct ssh2_connection_state *s,
PktIn *pktin, void *ctx)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
struct ssh_rportfwd *rpf = (struct ssh_rportfwd *)ctx;
if (pktin->type == SSH2_MSG_REQUEST_SUCCESS) {
ppl_logevent(("Remote port forwarding from %s enabled",
rpf->log_description));
} else {
ppl_logevent(("Remote port forwarding from %s refused",
rpf->log_description));
struct ssh_rportfwd *realpf = del234(s->rportfwds, rpf);
assert(realpf == rpf);
portfwdmgr_close(s->portfwdmgr, rpf->pfr);
free_rportfwd(rpf);
}
}
struct ssh_rportfwd *ssh2_rportfwd_alloc(
ConnectionLayer *cl,
const char *shost, int sport, const char *dhost, int dport,
int addressfamily, const char *log_description, PortFwdRecord *pfr,
ssh_sharing_connstate *share_ctx)
{
struct ssh2_connection_state *s =
container_of(cl, struct ssh2_connection_state, cl);
struct ssh_rportfwd *rpf = snew(struct ssh_rportfwd);
if (!s->rportfwds)
s->rportfwds = newtree234(ssh2_rportfwd_cmp);
rpf->shost = dupstr(shost);
rpf->sport = sport;
rpf->dhost = dupstr(dhost);
rpf->dport = dport;
rpf->addressfamily = addressfamily;
rpf->log_description = dupstr(log_description);
rpf->pfr = pfr;
rpf->share_ctx = share_ctx;
if (add234(s->rportfwds, rpf) != rpf) {
free_rportfwd(rpf);
return NULL;
}
if (!rpf->share_ctx) {
PktOut *pktout = ssh_bpp_new_pktout(
s->ppl.bpp, SSH2_MSG_GLOBAL_REQUEST);
put_stringz(pktout, "tcpip-forward");
put_bool(pktout, true); /* want reply */
put_stringz(pktout, rpf->shost);
put_uint32(pktout, rpf->sport);
pq_push(s->ppl.out_pq, pktout);
ssh2_queue_global_request_handler(
s, ssh2_rportfwd_globreq_response, rpf);
}
return rpf;
}
void ssh2_rportfwd_remove(ConnectionLayer *cl, struct ssh_rportfwd *rpf)
{
struct ssh2_connection_state *s =
container_of(cl, struct ssh2_connection_state, cl);
if (rpf->share_ctx) {
/*
* We don't manufacture a cancel-tcpip-forward message for
* remote port forwardings being removed on behalf of a
* downstream; we just pass through the one the downstream
* sent to us.
*/
} else {
PktOut *pktout = ssh_bpp_new_pktout(
s->ppl.bpp, SSH2_MSG_GLOBAL_REQUEST);
put_stringz(pktout, "cancel-tcpip-forward");
put_bool(pktout, false); /* _don't_ want reply */
put_stringz(pktout, rpf->shost);
put_uint32(pktout, rpf->sport);
pq_push(s->ppl.out_pq, pktout);
}
assert(s->rportfwds);
struct ssh_rportfwd *realpf = del234(s->rportfwds, rpf);
assert(realpf == rpf);
free_rportfwd(rpf);
}
SshChannel *ssh2_session_open(ConnectionLayer *cl, Channel *chan)
{
struct ssh2_connection_state *s =
container_of(cl, struct ssh2_connection_state, cl);
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
struct ssh2_channel *c = snew(struct ssh2_channel);
PktOut *pktout;
c->connlayer = s;
ssh2_channel_init(c);
c->halfopen = true;
c->chan = chan;
ppl_logevent(("Opening main session channel"));
pktout = ssh2_chanopen_init(c, "session");
pq_push(s->ppl.out_pq, pktout);
return &c->sc;
}
SshChannel *ssh2_serverside_x11_open(
ConnectionLayer *cl, Channel *chan, const SocketPeerInfo *pi)
{
assert(false && "Should never be called in the client");
return 0; /* placate optimiser */
}
SshChannel *ssh2_serverside_agent_open(ConnectionLayer *cl, Channel *chan)
{
assert(false && "Should never be called in the client");
return 0; /* placate optimiser */
}
static void ssh2_channel_response(
struct ssh2_channel *c, PktIn *pkt, void *ctx)
{
chan_request_response(c->chan, pkt->type == SSH2_MSG_CHANNEL_SUCCESS);
}
void ssh2channel_start_shell(SshChannel *sc, bool want_reply)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "shell", want_reply ? ssh2_channel_response : NULL, NULL);
pq_push(s->ppl.out_pq, pktout);
}
void ssh2channel_start_command(
SshChannel *sc, bool want_reply, const char *command)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "exec", want_reply ? ssh2_channel_response : NULL, NULL);
put_stringz(pktout, command);
pq_push(s->ppl.out_pq, pktout);
}
bool ssh2channel_start_subsystem(
SshChannel *sc, bool want_reply, const char *subsystem)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "subsystem", want_reply ? ssh2_channel_response : NULL, NULL);
put_stringz(pktout, subsystem);
pq_push(s->ppl.out_pq, pktout);
return true;
}
void ssh2channel_send_exit_status(SshChannel *sc, int status)
{
assert(false && "Should never be called in the client");
}
void ssh2channel_send_exit_signal(
SshChannel *sc, ptrlen signame, bool core_dumped, ptrlen msg)
{
assert(false && "Should never be called in the client");
}
void ssh2channel_send_exit_signal_numeric(
SshChannel *sc, int signum, bool core_dumped, ptrlen msg)
{
assert(false && "Should never be called in the client");
}
void ssh2channel_request_x11_forwarding(
SshChannel *sc, bool want_reply, const char *authproto,
const char *authdata, int screen_number, bool oneshot)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "x11-req", want_reply ? ssh2_channel_response : NULL, NULL);
put_bool(pktout, oneshot);
put_stringz(pktout, authproto);
put_stringz(pktout, authdata);
put_uint32(pktout, screen_number);
pq_push(s->ppl.out_pq, pktout);
}
void ssh2channel_request_agent_forwarding(SshChannel *sc, bool want_reply)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "auth-agent-req@openssh.com",
want_reply ? ssh2_channel_response : NULL, NULL);
pq_push(s->ppl.out_pq, pktout);
}
void ssh2channel_request_pty(
SshChannel *sc, bool want_reply, Conf *conf, int w, int h)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
strbuf *modebuf;
PktOut *pktout = ssh2_chanreq_init(
c, "pty-req", want_reply ? ssh2_channel_response : NULL, NULL);
put_stringz(pktout, conf_get_str(conf, CONF_termtype));
put_uint32(pktout, w);
put_uint32(pktout, h);
put_uint32(pktout, 0); /* pixel width */
put_uint32(pktout, 0); /* pixel height */
modebuf = strbuf_new();
write_ttymodes_to_packet(
BinarySink_UPCAST(modebuf), 2,
get_ttymodes_from_conf(s->ppl.seat, conf));
put_stringsb(pktout, modebuf);
pq_push(s->ppl.out_pq, pktout);
}
bool ssh2channel_send_env_var(
SshChannel *sc, bool want_reply, const char *var, const char *value)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "env", want_reply ? ssh2_channel_response : NULL, NULL);
put_stringz(pktout, var);
put_stringz(pktout, value);
pq_push(s->ppl.out_pq, pktout);
return true;
}
bool ssh2channel_send_serial_break(SshChannel *sc, bool want_reply, int length)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "break", want_reply ? ssh2_channel_response : NULL, NULL);
put_uint32(pktout, length);
pq_push(s->ppl.out_pq, pktout);
return true;
}
bool ssh2channel_send_signal(
SshChannel *sc, bool want_reply, const char *signame)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(
c, "signal", want_reply ? ssh2_channel_response : NULL, NULL);
put_stringz(pktout, signame);
pq_push(s->ppl.out_pq, pktout);
return true;
}
void ssh2channel_send_terminal_size_change(SshChannel *sc, int w, int h)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(c, "window-change", NULL, NULL);
put_uint32(pktout, w);
put_uint32(pktout, h);
put_uint32(pktout, 0); /* pixel width */
put_uint32(pktout, 0); /* pixel height */
pq_push(s->ppl.out_pq, pktout);
}
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