[channels.c channels.h mux.c ssh.c]
     Pause the mux channel while waiting for reply from aynch callbacks.
     Prevents misordering of replies if new requests arrive while waiting.

     Extend channel open confirm callback to allow signalling failure
     conditions as well as success. Use this to 1) fix a memory leak, 2)
     start using the above pause mechanism and 3) delay sending a success/
     failure message on mux slave session open until we receive a reply from
     the server.

     motivated by and with feedback from markus@
This commit is contained in:
Damien Miller 2010-05-21 14:57:10 +10:00
Родитель c6afb5f2c0
Коммит d530f5f471
5 изменённых файлов: 70 добавлений и 20 удалений

Просмотреть файл

@ -11,6 +11,18 @@
[ssh-add.c]
check that the certificate matches the corresponding private key before
grafting it on
- djm@cvs.openbsd.org 2010/05/14 23:29:23
[channels.c channels.h mux.c ssh.c]
Pause the mux channel while waiting for reply from aynch callbacks.
Prevents misordering of replies if new requests arrive while waiting.
Extend channel open confirm callback to allow signalling failure
conditions as well as success. Use this to 1) fix a memory leak, 2)
start using the above pause mechanism and 3) delay sending a success/
failure message on mux slave session open until we receive a reply from
the server.
motivated by and with feedback from markus@
20100511
- (dtucker) [Makefile.in] Bug #1770: Link libopenbsd-compat twice to solve

Просмотреть файл

@ -1,4 +1,4 @@
/* $OpenBSD: channels.c,v 1.303 2010/01/30 21:12:08 djm Exp $ */
/* $OpenBSD: channels.c,v 1.304 2010/05/14 23:29:23 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -330,6 +330,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
c->ctl_chan = -1;
c->mux_rcb = NULL;
c->mux_ctx = NULL;
c->mux_pause = 0;
c->delayed = 1; /* prevent call to channel_post handler */
TAILQ_INIT(&c->status_confirms);
debug("channel %d: new [%s]", found, remote_name);
@ -703,7 +704,7 @@ channel_register_status_confirm(int id, channel_confirm_cb *cb,
}
void
channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
{
Channel *c = channel_lookup(id);
@ -991,7 +992,7 @@ channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
static void
channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
{
if (c->istate == CHAN_INPUT_OPEN &&
if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
buffer_check_alloc(&c->input, CHAN_RBUF))
FD_SET(c->rfd, readset);
if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
@ -1840,7 +1841,7 @@ channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
if (!compat20)
fatal("%s: entered with !compat20", __func__);
if (c->rfd != -1 && FD_ISSET(c->rfd, readset) &&
if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
(c->istate == CHAN_INPUT_OPEN ||
c->istate == CHAN_INPUT_WAIT_DRAIN)) {
/*
@ -2463,7 +2464,7 @@ channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
c->remote_maxpacket = packet_get_int();
if (c->open_confirm) {
debug2("callback start");
c->open_confirm(c->self, c->open_confirm_ctx);
c->open_confirm(c->self, 1, c->open_confirm_ctx);
debug2("callback done");
}
debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
@ -2514,6 +2515,11 @@ channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
xfree(msg);
if (lang != NULL)
xfree(lang);
if (c->open_confirm) {
debug2("callback start");
c->open_confirm(c->self, 0, c->open_confirm_ctx);
debug2("callback done");
}
}
packet_check_eom();
/* Schedule the channel for cleanup/deletion. */

Просмотреть файл

@ -1,4 +1,4 @@
/* $OpenBSD: channels.h,v 1.103 2010/01/26 01:28:35 djm Exp $ */
/* $OpenBSD: channels.h,v 1.104 2010/05/14 23:29:23 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -60,6 +60,7 @@
struct Channel;
typedef struct Channel Channel;
typedef void channel_open_fn(int, int, void *);
typedef void channel_callback_fn(int, void *);
typedef int channel_infilter_fn(struct Channel *, char *, int);
typedef void channel_filter_cleanup_fn(int, void *);
@ -130,7 +131,7 @@ struct Channel {
char *ctype; /* type */
/* callback */
channel_callback_fn *open_confirm;
channel_open_fn *open_confirm;
void *open_confirm_ctx;
channel_callback_fn *detach_user;
int detach_close;
@ -151,6 +152,7 @@ struct Channel {
/* multiplexing protocol hook, called for each packet received */
mux_callback_fn *mux_rcb;
void *mux_ctx;
int mux_pause;
};
#define CHAN_EXTENDED_IGNORE 0
@ -208,7 +210,7 @@ void channel_stop_listening(void);
void channel_send_open(int);
void channel_request_start(int, char *, int);
void channel_register_cleanup(int, channel_callback_fn *, int);
void channel_register_open_confirm(int, channel_callback_fn *, void *);
void channel_register_open_confirm(int, channel_open_fn *, void *);
void channel_register_filter(int, channel_infilter_fn *,
channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
void channel_register_status_confirm(int, channel_confirm_cb *,

47
mux.c
Просмотреть файл

@ -1,4 +1,4 @@
/* $OpenBSD: mux.c,v 1.16 2010/04/23 22:27:38 djm Exp $ */
/* $OpenBSD: mux.c,v 1.17 2010/05/14 23:29:23 djm Exp $ */
/*
* Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
*
@ -106,6 +106,7 @@ struct mux_session_confirm_ctx {
char *term;
struct termios tio;
char **env;
u_int rid;
};
/* fd to control socket */
@ -149,7 +150,7 @@ struct mux_master_state {
#define MUX_FWD_REMOTE 2
#define MUX_FWD_DYNAMIC 3
static void mux_session_confirm(int, void *);
static void mux_session_confirm(int, int, void *);
static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *);
static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *);
@ -301,6 +302,7 @@ process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
/* Reply for SSHMUX_COMMAND_OPEN */
cctx = xcalloc(1, sizeof(*cctx));
cctx->term = NULL;
cctx->rid = rid;
cmd = reserved = NULL;
if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
buffer_get_int_ret(&cctx->want_tty, m) != 0 ||
@ -454,14 +456,10 @@ process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
channel_send_open(nc->self);
channel_register_open_confirm(nc->self, mux_session_confirm, cctx);
c->mux_pause = 1; /* stop handling messages until open_confirm done */
channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
/* prepare reply */
/* XXX defer until mux_session_confirm() fires */
buffer_put_int(r, MUX_S_SESSION_OPENED);
buffer_put_int(r, rid);
buffer_put_int(r, nc->self);
/* reply is deferred, sent by mux_session_confirm */
return 0;
}
@ -1000,17 +998,31 @@ muxserver_listen(void)
/* Callback on open confirmation in mux master for a mux client session. */
static void
mux_session_confirm(int id, void *arg)
mux_session_confirm(int id, int success, void *arg)
{
struct mux_session_confirm_ctx *cctx = arg;
const char *display;
Channel *c;
Channel *c, *cc;
int i;
Buffer reply;
if (cctx == NULL)
fatal("%s: cctx == NULL", __func__);
if ((c = channel_by_id(id)) == NULL)
fatal("%s: no channel for id %d", __func__, id);
if ((cc = channel_by_id(c->ctl_chan)) == NULL)
fatal("%s: channel %d lacks control channel %d", __func__,
id, c->ctl_chan);
if (!success) {
debug3("%s: sending failure reply", __func__);
/* prepare reply */
buffer_init(&reply);
buffer_put_int(&reply, MUX_S_FAILURE);
buffer_put_int(&reply, cctx->rid);
buffer_put_cstring(&reply, "Session open refused by peer");
goto done;
}
display = getenv("DISPLAY");
if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
@ -1033,6 +1045,21 @@ mux_session_confirm(int id, void *arg)
client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
debug3("%s: sending success reply", __func__);
/* prepare reply */
buffer_init(&reply);
buffer_put_int(&reply, MUX_S_SESSION_OPENED);
buffer_put_int(&reply, cctx->rid);
buffer_put_int(&reply, c->self);
done:
/* Send reply */
buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
buffer_free(&reply);
if (cc->mux_pause <= 0)
fatal("%s: mux_pause %d", __func__, cc->mux_pause);
cc->mux_pause = 0; /* start processing messages again */
c->open_confirm_ctx = NULL;
buffer_free(&cctx->cmd);
xfree(cctx->term);

7
ssh.c
Просмотреть файл

@ -1,4 +1,4 @@
/* $OpenBSD: ssh.c,v 1.336 2010/04/10 00:00:16 djm Exp $ */
/* $OpenBSD: ssh.c,v 1.337 2010/05/14 23:29:23 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -1175,12 +1175,15 @@ ssh_session(void)
/* request pty/x11/agent/tcpfwd/shell for channel */
static void
ssh_session2_setup(int id, void *arg)
ssh_session2_setup(int id, int success, void *arg)
{
extern char **environ;
const char *display;
int interactive = tty_flag;
if (!success)
return; /* No need for error message, channels code sens one */
display = getenv("DISPLAY");
if (options.forward_x11 && display != NULL) {
char *proto, *data;