- djm@cvs.openbsd.org 2008/05/08 12:02:23

[auth-options.c auth1.c channels.c channels.h clientloop.c gss-serv.c] [monitor.c monitor_wrap.c nchan.c servconf.c serverloop.c session.c] [ssh.c sshd.c] Implement a channel success/failure status confirmation callback mechanism. Each channel maintains a queue of callbacks, which will be drained in order (RFC4253 guarantees confirm messages are not reordered within an channel). Also includes a abandonment callback to clean up if a channel is closed without sending confirmation messages. This probably shouldn't happen in compliant implementations, but it could be abused to leak memory. ok markus@ (as part of a larger diff)
2008-05-19 15:05:07 +10:00 · 2008-05-19 15:05:07 +10:00 · b84886ba3e
parent db255cad05
commit b84886ba3e
15 changed files with 132 additions and 31 deletions
--- a/15
+++ b/15
@ -62,6 +62,19 @@
     [bufaux.c buffer.h channels.c packet.c packet.h]
     avoid extra malloc/copy/free when receiving data over the net;
     ~10% speedup for localhost-scp; ok djm@
+   - djm@cvs.openbsd.org 2008/05/08 12:02:23
+     [auth-options.c auth1.c channels.c channels.h clientloop.c gss-serv.c]
+     [monitor.c monitor_wrap.c nchan.c servconf.c serverloop.c session.c]
+     [ssh.c sshd.c]
+     Implement a channel success/failure status confirmation callback
+     mechanism. Each channel maintains a queue of callbacks, which will
+     be drained in order (RFC4253 guarantees confirm messages are not
+     reordered within an channel).
+     Also includes a abandonment callback to clean up if a channel is
+     closed without sending confirmation messages. This probably
+     shouldn't happen in compliant implementations, but it could be
+     abused to leak memory.
+     ok markus@ (as part of a larger diff)

 20080403
 - (djm) [openbsd-compat/bsd-poll.c] Include stdlib.h to avoid compile-
@ -3922,4 +3935,4 @@
   OpenServer 6 and add osr5bigcrypt support so when someone migrates
   passwords between UnixWare and OpenServer they will still work. OK dtucker@

-$Id: ChangeLog,v 1.4919 2008/05/19 04:59:37 djm Exp $
+$Id: ChangeLog,v 1.4920 2008/05/19 05:05:07 djm Exp $
--- a/auth-options.c
+++ b/auth-options.c
@ -1,4 +1,4 @@
-/* $OpenBSD: auth-options.c,v 1.41 2008/03/26 21:28:14 djm Exp $ */
+/* $OpenBSD: auth-options.c,v 1.42 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -20,6 +20,7 @@
 #include <stdio.h>
 #include <stdarg.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "match.h"
 #include "log.h"
--- a/auth1.c
+++ b/auth1.c
@ -1,4 +1,4 @@
-/* $OpenBSD: auth1.c,v 1.71 2007/09/21 08:15:29 djm Exp $ */
+/* $OpenBSD: auth1.c,v 1.72 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
@ -20,6 +20,7 @@
 #include <unistd.h>
 #include <pwd.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "rsa.h"
 #include "ssh1.h"
--- a/channels.c
+++ b/channels.c
@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.274 2008/05/08 06:59:01 markus Exp $ */
+/* $OpenBSD: channels.c,v 1.275 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -61,6 +61,7 @@
 #include <unistd.h>
 #include <stdarg.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "ssh1.h"
@ -319,10 +320,11 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 	c->single_connection = 0;
 	c->detach_user = NULL;
 	c->detach_close = 0;
-	c->confirm = NULL;
-	c->confirm_ctx = NULL;
+	c->open_confirm = NULL;
+	c->open_confirm_ctx = NULL;
 	c->input_filter = NULL;
 	c->output_filter = NULL;
+	TAILQ_INIT(&c->status_confirms);
 	debug("channel %d: new [%s]", found, remote_name);
 	return c;
 }
@ -379,6 +381,7 @@ channel_free(Channel *c)
 {
 	char *s;
 	u_int i, n;
+	struct channel_confirm *cc;

 	for (n = 0, i = 0; i < channels_alloc; i++)
 		if (channels[i])
@ -402,6 +405,13 @@ channel_free(Channel *c)
 		xfree(c->remote_name);
 		c->remote_name = NULL;
 	}
+	while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
+		if (cc->abandon_cb != NULL)
+			cc->abandon_cb(c, cc->ctx);
+		TAILQ_REMOVE(&c->status_confirms, cc, entry);
+		bzero(cc, sizeof(*cc));
+		xfree(cc);
+	}
 	channels[c->self] = NULL;
 	xfree(c);
 }
@ -660,16 +670,33 @@ channel_request_start(int id, char *service, int wantconfirm)
 }

 void
-channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
+channel_register_status_confirm(int id, channel_confirm_cb *cb,
+    channel_confirm_abandon_cb *abandon_cb, void *ctx)
+{
+	struct channel_confirm *cc;
+	Channel *c;
+
+	if ((c = channel_lookup(id)) == NULL)
+		fatal("channel_register_expect: %d: bad id", id);
+
+	cc = xmalloc(sizeof(*cc));
+	cc->cb = cb;
+	cc->abandon_cb = abandon_cb;
+	cc->ctx = ctx;
+	TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
+}
+
+void
+channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
 {
 	Channel *c = channel_lookup(id);

 	if (c == NULL) {
-		logit("channel_register_comfirm: %d: bad id", id);
+		logit("channel_register_open_comfirm: %d: bad id", id);
 		return;
 	}
-	c->confirm = fn;
-	c->confirm_ctx = ctx;
+	c->open_confirm = fn;
+	c->open_confirm_ctx = ctx;
 }

 void
@ -2209,9 +2236,9 @@ channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
 	if (compat20) {
 		c->remote_window = packet_get_int();
 		c->remote_maxpacket = packet_get_int();
-		if (c->confirm) {
+		if (c->open_confirm) {
 			debug2("callback start");
-			c->confirm(c->self, c->confirm_ctx);
+			c->open_confirm(c->self, c->open_confirm_ctx);
 			debug2("callback done");
 		}
 		debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
@ -2328,6 +2355,34 @@ channel_input_port_open(int type, u_int32_t seq, void *ctxt)
 	xfree(host);
 }

+/* ARGSUSED */
+void
+channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
+{
+	Channel *c;
+	struct channel_confirm *cc;
+	int remote_id;
+
+	/* Reset keepalive timeout */
+	keep_alive_timeouts = 0;
+
+	remote_id = packet_get_int();
+	packet_check_eom();
+
+	debug2("channel_input_confirm: type %d id %d", type, remote_id);
+
+	if ((c = channel_lookup(remote_id)) == NULL) {
+		logit("channel_input_success_failure: %d: unknown", remote_id);
+		return;
+	}	
+	;
+	if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
+		return;
+	cc->cb(type, c, cc->ctx);
+	TAILQ_REMOVE(&c->status_confirms, cc, entry);
+	bzero(cc, sizeof(*cc));
+	xfree(cc);
+}

 /* -- tcp forwarding */

--- a/channels.h
+++ b/channels.h
@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.89 2007/06/11 09:14:00 markus Exp $ */
+/* $OpenBSD: channels.h,v 1.90 2008/05/08 12:02:23 djm Exp $ */

 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -64,6 +64,17 @@ typedef void channel_callback_fn(int, void *);
 typedef int channel_infilter_fn(struct Channel *, char *, int);
 typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);

+/* Channel success/failure callbacks */
+typedef void channel_confirm_cb(int, struct Channel *, void *);
+typedef void channel_confirm_abandon_cb(struct Channel *, void *);
+struct channel_confirm {
+	TAILQ_ENTRY(channel_confirm) entry;
+	channel_confirm_cb *cb;
+	channel_confirm_abandon_cb *abandon_cb;
+	void *ctx;
+};
+TAILQ_HEAD(channel_confirms, channel_confirm);
+
 struct Channel {
 	int     type;		/* channel type/state */
 	int     self;		/* my own channel identifier */
@ -104,10 +115,11 @@ struct Channel {
 	char   *ctype;		/* type */

 	/* callback */
-	channel_callback_fn	*confirm;
-	void			*confirm_ctx;
+	channel_callback_fn	*open_confirm;
+	void			*open_confirm_ctx;
 	channel_callback_fn	*detach_user;
 	int			detach_close;
+	struct channel_confirms	status_confirms;

 	/* filter */
 	channel_infilter_fn	*input_filter;
@ -170,8 +182,11 @@ 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_confirm(int, channel_callback_fn *, void *);
-void	 channel_register_filter(int, channel_infilter_fn *, channel_outfilter_fn *);
+void	 channel_register_open_confirm(int, channel_callback_fn *, void *);
+void	 channel_register_filter(int, channel_infilter_fn *,
+    channel_outfilter_fn *);
+void	 channel_register_status_confirm(int, channel_confirm_cb *,
+    channel_confirm_abandon_cb *, void *);
 void	 channel_cancel_cleanup(int);
 int	 channel_close_fd(int *);
 void	 channel_send_window_changes(void);
@ -188,6 +203,7 @@ void	 channel_input_open_confirmation(int, u_int32_t, void *);
 void	 channel_input_open_failure(int, u_int32_t, void *);
 void	 channel_input_port_open(int, u_int32_t, void *);
 void	 channel_input_window_adjust(int, u_int32_t, void *);
+void	 channel_input_status_confirm(int, u_int32_t, void *);

 /* file descriptor handling (read/write) */

--- a/clientloop.c
+++ b/clientloop.c
@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.188 2008/02/22 20:44:02 dtucker Exp $ */
+/* $OpenBSD: clientloop.c,v 1.189 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -86,6 +86,7 @@
 #include <pwd.h>
 #include <unistd.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "ssh1.h"
@ -700,7 +701,7 @@ client_extra_session2_setup(int id, void *arg)
 	    cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
 	    client_subsystem_reply);

-	c->confirm_ctx = NULL;
+	c->open_confirm_ctx = NULL;
 	buffer_free(&cctx->cmd);
 	xfree(cctx->term);
 	if (cctx->env != NULL) {
@ -940,7 +941,8 @@ client_process_control(fd_set *readset)
 	debug3("%s: channel_new: %d", __func__, c->self);

 	channel_send_open(c->self);
-	channel_register_confirm(c->self, client_extra_session2_setup, cctx);
+	channel_register_open_confirm(c->self,
+	    client_extra_session2_setup, cctx);
 }

 static void
@ -2068,6 +2070,8 @@ client_init_dispatch_20(void)
 	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
 	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
 	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
+	dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
+	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
 	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);

 	/* rekeying */
--- a/gss-serv.c
+++ b/gss-serv.c
@ -1,4 +1,4 @@
-/* $OpenBSD: gss-serv.c,v 1.21 2007/06/12 08:20:00 djm Exp $ */
+/* $OpenBSD: gss-serv.c,v 1.22 2008/05/08 12:02:23 djm Exp $ */

 /*
 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
@ -35,6 +35,7 @@
 #include <string.h>
 #include <unistd.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "buffer.h"
 #include "key.h"
--- a/monitor.c
+++ b/monitor.c
@ -1,4 +1,4 @@
-/* $OpenBSD: monitor.c,v 1.94 2007/10/29 04:08:08 dtucker Exp $ */
+/* $OpenBSD: monitor.c,v 1.95 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Copyright 2002 Niels Provos <provos@citi.umich.edu>
 * Copyright 2002 Markus Friedl <markus@openbsd.org>
@ -51,6 +51,7 @@

 #include <openssl/dh.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "key.h"
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@ -1,4 +1,4 @@
-/* $OpenBSD: monitor_wrap.c,v 1.60 2007/10/29 04:08:08 dtucker Exp $ */
+/* $OpenBSD: monitor_wrap.c,v 1.61 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Copyright 2002 Niels Provos <provos@citi.umich.edu>
 * Copyright 2002 Markus Friedl <markus@openbsd.org>
@ -41,6 +41,7 @@
 #include <openssl/bn.h>
 #include <openssl/dh.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "dh.h"
--- a/nchan.c
+++ b/nchan.c
@ -1,4 +1,4 @@
-/* $OpenBSD: nchan.c,v 1.57 2006/08/03 03:34:42 deraadt Exp $ */
+/* $OpenBSD: nchan.c,v 1.58 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
 *
@ -32,6 +32,7 @@
 #include <string.h>
 #include <stdarg.h>

+#include "openbsd-compat/sys-queue.h"
 #include "ssh1.h"
 #include "ssh2.h"
 #include "buffer.h"
--- a/servconf.c
+++ b/servconf.c
@ -1,4 +1,4 @@
-/* $OpenBSD: servconf.c,v 1.178 2008/05/07 05:49:37 pyr Exp $ */
+/* $OpenBSD: servconf.c,v 1.179 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
@ -24,6 +24,7 @@
 #include <unistd.h>
 #include <stdarg.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "log.h"
--- a/serverloop.c
+++ b/serverloop.c
@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.148 2008/02/22 20:44:02 dtucker Exp $ */
+/* $OpenBSD: serverloop.c,v 1.149 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -56,6 +56,7 @@
 #include <unistd.h>
 #include <stdarg.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "packet.h"
 #include "buffer.h"
@ -1188,8 +1189,9 @@ server_init_dispatch_20(void)
 	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
 	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
 	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
+	dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
+	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
 	/* client_alive */
-	dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
 	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
 	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
 	/* rekeying */
--- a/session.c
+++ b/session.c
@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.235 2008/05/07 05:49:37 pyr Exp $ */
+/* $OpenBSD: session.c,v 1.236 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
@ -59,6 +59,7 @@
 #include <string.h>
 #include <unistd.h>

+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "ssh1.h"
--- a/ssh.c
+++ b/ssh.c
@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.309 2008/01/19 20:51:26 djm Exp $ */
+/* $OpenBSD: ssh.c,v 1.310 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -73,6 +73,7 @@
 #include <openssl/evp.h>
 #include <openssl/err.h>
 #include "openbsd-compat/openssl-compat.h"
+#include "openbsd-compat/sys-queue.h"

 #include "xmalloc.h"
 #include "ssh.h"
@ -1195,7 +1196,8 @@ ssh_session2_open(void)

 	channel_send_open(c->self);
 	if (!no_shell_flag)
-		channel_register_confirm(c->self, ssh_session2_setup, NULL);
+		channel_register_open_confirm(c->self,
+		    ssh_session2_setup, NULL);

 	return c->self;
 }
--- a/sshd.c
+++ b/sshd.c
@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.356 2008/04/13 00:22:17 djm Exp $ */
+/* $OpenBSD: sshd.c,v 1.357 2008/05/08 12:02:23 djm Exp $ */
 /*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -54,6 +54,7 @@
 # include <sys/time.h>
 #endif
 #include "openbsd-compat/sys-tree.h"
+#include "openbsd-compat/sys-queue.h"
 #include <sys/wait.h>

 #include <errno.h>